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FHE NAUTILUS

				Volume 107, Number 1 March 24, 1993 ISSN 0028-1344
	A quarterly devoted to malacology.
			APR	1 19S3
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EDITOR-IN-CHIEF Dr. M. G. Harasewych Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560

ASSOCIATE EDITOR Dr. R. Tucker Abbott American Malacologists, Inc. P.O. Box 2255 Melbourne, FL 32902

CONSULTING EDITORS Dr. Riidiger Bieler Department of Invertebrates Field Museum of Natural History Chicago, IL 60605

Dr. Robert T. Dillon, Jr. Department of Biology College of Charleston Charleston, SC 29424

Dr. William K. Emerson

Department of Living Invertebrates

The American Museum of Natural

History

New York, NY 10024

Dr. Robert Hershler Division of Mollusks National Museum of Natural History Smithsonian Institution Washington. DC 20560

Dr. Richard S. Houbrick Division of Mollusks National Museum of Natural History Smithsonian Institution Washington, DC 20560

Mr. Richard I. Johnson Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138

Dr. Aurele La Rocque Department of Geology The Ohio State University Columbus, OH 43210

Dr. James H. McLean

Department of Malacology Los Angeles County Museum ol Natural History 900 E.xposition Boulevard Los Angeles, CA 90007

Dr. Arthur S. Merrill % Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138

Ms. Paula M. Mikkelsen Harbor Branch Oceanographic Institution, Inc. Ft. Pierce, FL 33450

Dr. Donald R. Moore

Division of Marine Geology

and Geophysics

Rosenstiel School of Marine and

Atmospheric Science

University of Miami

4600 Rickenbacker Causeway

Miami, FL 33149

Dr. Gustav Paula\ Marine Laborator\- University of Guam Mangilao', (^.uarn 96923

Mr. Richard L. IVtit

P.O. Bo.\ 30

North Myrtle Beach, SC 29582

Dr. Edward J. Petuch Department of Geology Florida ,\tlantic University Boca Raton, FL 33431

Dr. David H. Stansbery Museum of Zoology The Ohio State University Columbus, OH 43210

Dr. Ruth D. Turner Department of Mollusks Museum of Comparative Zoology Harvard University Cambridge, MA 02138

Dr. Geerat J. Vermeij Department of Geology University of California at Davis Davis, CA 95616

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TH Et^NAUTI LUS

CONTENTS

Volume 107, Number 1 March 24, 1993 ISSN 0028-1344

I IPD/\pv '

Limacosphaera, an I'nusual Mesogastropod (Lamellariidae)

Larva of the Weddell Sea (Antarctica) , 1

)_ Hole, Mass. j

The Reproductive Anatomy of Philomycus sellatits

Hubricht, 1972 and Philomycus virginiciis Hubricht, 1953

(Gastropoda: Philomycidae) 9

Two Confusing Indo-Pacific Cerithiids 14

Rediscovery of Tiirbinella thersites Reeve, 1847, with

Notes on its Taxonomic Position (Gastropoda:

Fasciolariidae) 24

The Rediscovery, Morphology, and Identity of Conus

emersoni Hanna, 1963 29

The Benthic Mollusk Faunas of Two Contrasting Reef

Paleosubenvironments: Falmouth Formation (late

Pleistocene, Last Interglacial), Jamaica 33

Klaus Bandel Stefan Hain Frank Riedel Henry Tieniann

H. Lee Fairbanks

Richard S. Houbrick

R. N. Kilburn

John K. Tucker James H. McLean

Stephen K. Donovan D. T. J. Litllewood

THE NAUTILUS 107(l):l-8, 1993

Page 1

Limacosphaera, an Unusual Mesogastropod (Lamellariidae) Larva of the Weddell Sea (Antarctica)

Klaus Bandel

Gediogiseli-Puliiontiilogisclies

Institut und Museum Universit) of Hamburg BundesstraBe 55 2000 Hamburg 13 GERMANY

Slefan Main

A If red- Wegener- Institut fiir

Polar- und Meeresforschung CoiumbusstraBe 2850 Bremerhaven GERMANY

Frank Riedel

Geologiseh-PalaoiUulogisches

Institut und Museum University of Hamburg BundesstraBe 55 2000 Hamburg 13 GERMANY

Henry Tiemann

Zooiogisches Institut und Museum University of Hamburg Martin-Lutlier-King-Piatz 3 2000 Hamburg 13 GERMANY

ABSTRACT

Marsciiiopsis conica Smith. 1915 and M mollis (Smith. 1902) have pianktotrophic larvae that are unique among gastropods. They cover the larval shell with a lacunous muscular mantle that can change its volume by interaction of body fluid and muscle activity This limacosphaera larva is found in Antarctic waters and represents the most complex larval strategy within the "echinospira-group' . Notes on the biology and anatomy, including histology, of this larva are presented.

Ketj ivords: Lamellariidae, Marseniopsis. larvae, Antarctica.

introduc;tion

The majority of benthic invertebrates of high-Antarctic seas brood their young or provide postspawning parental care rather than produce free-Uving larvae (Mileikovsky, 197L Picken, 1980). True pianktotrophic pelagic larvae are extremely rare in the 200 to 600 m deep high-Ant- arctic shelf areas.

Plankton samples taken by the R/V polarstern in the eastern Weddell Sea during several late winter to late summer cruises yielded only two meropelagic larvae of benthic gastropods (Piatowski, 1987; Boysen-Ennen, 1987). Both of these larval types were regularly found. One of these is Capulus subcompressus Pelseneer, 1903, which had first been observed by Pelseneer (1903) and is described in detail by Bandel and Hain (in prepara- tion). The second lueropelagic larvae was first observed by Simroth (1914) in material from the Davis Sea. Sim- roth noted anatomical similarity to a planktonic gastro- pod from the deep sea areas of the Indian Ocean, which

he described earlier as Limacosphaera macdonaldi (Sim- roth, 1908).

This animal is a spherical, transparent, voluminous gastropod with two openings: one to allow head and foot to come out of the shell and the other situated on the opposite side of the sphere (Simroth, 1908, 1914). Simroth called the muscular inantle covering the larval shell the deutoconcha of the limacosphaera. The posterior pore, which he (1908) called the shell tunnel (Schalengang), connects the sea water with a cavity surrounding much of the thin organic shell. Simroth (1914) also suggested the presence of glandular cells and muscle fibers in the voluminous deutoconcha that surrounds the shell. He noticed that the Antarctic forms represented larvae rath- er than adult gastropods as he had originally assumed when describing Limacosphaera as a new genus of pe- lagic gastropods (Pteropoda). Simroth (1914) correctly placed these larvae into the ontogeny of members of the "echinospira-group" in the genus Marseniopsis. The term limacosphaera was retained, now to describe a very pe- culiar and characteristic larva.

Simroth (1908, 1914) considered that the limaco- sphaera swam with the aid of their large velum. Another mode of sw imming, mainly by hydrostatic effects, was considered the likely mode of propulsion in the water column by Jevdonin and Minichev (1975).

These authors observed developing spawn of Marsen- iopsis conica and foimd that the mantle of the embryo envelops the shell prior to hatching from an egg mass found in excavations of tunicate surfaces. Jevdonin and Minichev (1975) also noted that the mantle did not fuse completely but left an open shell pore. They seem not

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THE NAUTILUS, Vol. 107, No. 1

Figures 1, 2. Adult animals ol I. Marseniopsis conica Smith, 1915, and 2. M. mollis (Smith, 1902). Dorsal views on left, showing mantles that are fused ahove the shell and cannot be retracted. Neutral \ lews on right, show foot, parts of the head \\\ illustrations drawn irom fi.\ed animals. Scale bar = 5 mm for figure I, 10 mm for figure 2.

to have been aware of the earlier cie.scriptions of these larvae by Simroth (1908, 1914). Jevcloiiin aiul Miiiichev (1975) suggested that larvae with a size of about 20 mm in diameter were nearly ready to metamorpho.se. Their descriptions suggest that their observations had been car- ried out on preserved material and they most probably did not .see living larvae or embryos.

We provide a new description of the histology of these

larvae integrated with observations on the li\iiig forms and their metamorphosis.

MATERIALS AND METHODS

During the cruises polarsirkel 80/81, polarstern ant I, ANT III/3, ANT V/S and ant \'II/4 larvae of the li- macosphaera type were caught at about 100 stations in

K. Bandel et al., 1993

Page 3

— grounding linie

Icnntinenlal boundary)

W •" E

Figure 3. Map indicating location of the Wedell Sea and the area where the larvae of Marseniopsis were caught.

neritic \\ aters above continental shelf areas of the eastern Weddell Sea (figure 3). Samples were taken with various plankton gears (mesh sizes of 0.335-4.5 mm) in upper water layers (300-0 m) and preserved in buffered for- malin.

Six larvae were kept alive for six weeks during the expedition PS ant V/3. During this period they were fed two times with a diatom suspension. Only one of the larvae survived and metamorphosed four weeks after capture (November 1986). It was fixed in 70% ethanol.

During the expedition PS ant VII/4 (January to March 1989) 42 living limacosphaera from RMT samples were photographed for size measurements and transfered in- dividually to small plastic aquaria (running water system, temperature adjusted to 0 °C). The larvae were fed once a week with a suspension of Antarctic diatoms. After 8 and 13 months the photographic measurements of larvae or juveniles were repeated.

The larval shell, the thick, whitish to semitransparent tissue covering it (deutoconcha), and the juvenile shell were studied on 10 critical-point dried specimens using a SEM.

In May 1989, six living larvae were fixed for histolog- ical studies in 4% seawater-formalin or 2.5% seawater- glutaraldehyde. One limacosphaera fixed in formalin was dehydrated using isopropanol. It was then treated with benzylbenzoate, embedded in paraplast, serially sec- tioned (7 ytm) and stained with Helioechtrubin BBL/ Acidgreen 5/Acidorange 10 after Halmi (Adam & Czi- hak, 1964).

To detect lipids whole larvae without the deutoconcha as well as parts of the deutoconcha were treated using the oil-red-niethod (Romeis, 1968). These samples were embedded in glycerin and examined with a light mi- croscope.

Another limacosphaera fixed in glutaraldehyde was osmicated in 1% osmium tetroxide, dehydrated in ace-

Figure 4. Larva of Marseniopsis cf. mollis. Schematic drawing from several photr)graphs of living specimens. One quarter of the shell-covering tissue (deutoconcha) is removed, d, deuto- concha; e, eye; ed, epidermis; f, foot; s, shell; si, siphon; st, apical tube; t, tentacle; v, velum.

tone and embedded in Spurr's fluid. Sections were cut at ca. 80 nm to 1 ^m using an ultramicrotome (Reichert). The 80 nm sections were stained with uranyl acetate and lead citrate, then examined and photographed using a TEM (Zeiss). The 1 ^m sections were stained with To- luidine Blue and Pyronin and examined with a light microscope.

Voucher material is deposited at the Zoological Insti- tute and Museum (L'niversity of Hamburg) (cat. no. M 885).

RESULTS

The Living Larva

Description: The shape of the limacosphaera (figures 4-6) is globular with an overall diameter ranging from 1.8 to 20 mm. The actual larval shell is covered by the deutoconcha. Some of the larvae have granular deposits in the outer layer of the deutoconcha. On the ventral side of the larva (figure 6) there is a slit-like opening for the foot and the four large velar lobes. This opening is extended anteriorly by a siphon-like, semicircular groove. A second, small, tunnel-like excavation extends from the apical region of the shell to the surface of the deutocon- cha. Observations on living larvae sorted from plankton samples show that both openings can be closed and that the deutoconcha produces much hyaline mucus.

During metamorphosis the shell is still barely calcified (figure 7), becoming solidly calcified right after meta- morphosis (figure 8). The larval shell reaches 2.3 whorls with fine spiral threads on the first 1.5 whorls. Earliest growth lines are visible after 0.8 whorls (figure 9 arrow). In well fed larvae, the greenish visceral mass can be seen through the shell and the deutoconcha.

All studied larvae had a well developed foot. The eyes are at the base of the tentacles. In contrast to Simroth's original description of Limacosphaera macdonaldi from

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THE NAUTILUS, Vol. 107, No. 1

Figures 5, 6. Living larvae ul A/(j),Miii(>/;.si.v cj. mollis. 5. Dorsal view. 6. Ventral view, with foot, velum, tentacles and eyes visible. Scale bars = 5 mm for liolh pliotograjihs

the tropics, the operculum is absent in the Antarctic specimens.

Biology

Deposition of egg capsules in the tests of compound as- cidians is known for temperate lamellarian species (Fret- ter & Graham, 1962). Antarctic species have the same spawning habit (Jevdonin & Minichev, 1975; P. Dayton, personal communication). One compound ascidian with appro.xiinately 20 egg capsules was obtained in February 1989. Although maintained in an aquarium, the eggs failed to develop.

Figures 7-9. Shell of Marseniopsis cj. mollis. 7. During meta- morphosis, the shell is barely calcified and therefore, flexible. 8. .Alter metamorphosis, shell solidly calcified and lias reached 2 4 whorls. 9. Same specimen as in fig, 8. P'irst growth lines (arrow) are visible at 0 7 whorls of the shell The sjjiral threads end at 1.4 whorls. Scale bars = 1 mm in all photographs.

Larval size, as well as the time and location of sam- pling, indicates that hatching of larvae occurs from late winter to austral summer in the shelf areas of the eastern Weddell Sea.

The smallest larvae found have a diameter of 1.8 mm. We suggest that this size is reached shortK after the larvae have hatched and risen from the l)ottoni. Aquar- ium observations indicate that the larvae rise by buoy- ancy. The large velar lobes are not used or have only secondary function. The buoyancy control mechanism is uiikuow n.

In the northern shell areas of the Weddell Sea the amount of food (0.07 ixg chlorophyll -a/liter) is more

K. Bandel et al., 1993

Page 5

Figure 10. ScluMiuitir draw iiig ot the ajMciil lulx' (shell tuiiiu-lj of Marseniopsis cf. mollis, c, cilia; cc, collagenous cell; cf, collagen fibers; gc, gland cell; mf, muscular fibers; mv, micro- villi; n, nuclei; s, shell; st, apical tube

limited even during phytoplankton blooms. In open wa- ters or polynyas (ice free areas), the phytoplankton con- centration barely reaches 1.5 ng chi a/liter. It is sus- pected that growth of larvae in these areas takes a much longer time.

The total Hpid content of larvae caught in February (end of austral summer) is low (3.5% dry weight) in comparison to other planktonic organisms. Seventy per- cent of these lipids are triacylglycerols (Hagen, 1988).

Although fed only twice, one limacosphaera caught in October 1986 metamorphosed four weeks later. During PS Ant VII/4 small larvae with a diameter of 3.9 mm began to metamorphose in the aquaria after 10 to 24 hours, while specimens of 10 mm diameter remained in the larval stage for up to 8 weeks. One specimen caught in the end of February 1989 was still in the larval stage when it died in August 1990.

Predatory pressure on the larvae seems to be very low. The shell-covering tissue of juveniles and adults is known to produce acidic secretions.

HISTOLOGY

Observations with Light Microscope

The deutoconcha of the limacosphaera consists of tissue that is composed of an outer epidermis, a central, cav- ernous connective tissue, and an inner epidermis cov- ering the shell.

The outer epidermis is composed of a single layer of cells with flattened nuclei and immersed, large, light, glandular cells with a single nucleus. Below it is a vo- luminous, spacious connective tissue, consisting of col- lagenous and muscular fibers with few cells suspended in it. The inner epidermis is a single layer of cells sup- ported by connective tissue and muscle fibers. These cells are stretched in length, and their nuclei are even more flattened than those of the outer epidermis.

The deutoconcha of the limacosphaera is connected

to the inner mantle of the apertural region of the shell by an especially strong muscular bridge of tissue. The outer mantle rests on the shell near the aperture and forms the connection to the inner mantle covering the visceral mass and the pallial cavity. Outer and inner mantle are "divided" from each other by the periostraca! gland zone characterized by the presence of many nuclei.

On the apical side of the deutoconcha the e.xternal mantle is pierced by a tube-like canal (figure 10, st) connecting sea water and shell surface. This canal is lined with a rugged, ciliated epithelium (figure 10, c) that continues along the inner mantle for about 0.4 mm, to form a small cavity between shell and mantle (figure 10). The tissue below the ciliated epithelium of the canal contains an agglomeration of large light epithelial glan- dular cells.

The iimer side of the deutoconcha connects to the organic shell that is composed of a double-layered peri- ostracum. This shell in its apical portion is filled with the visceral mass containing the large digestive gland. Its diverticula consist of large endodermal cells with basal nuclei and small cavities. The apical portion of the di- gestive gland is glandular and contains three different types of stored substances. The most basal portion con- tains proteins, somewhat above lie a large number of spherical bodies. Scale-like storage material that is weak- ly aeidophilous is suspended between these.

The spherical bodies (6-19 ^m in diameter) are lipids (analysed by oil-red method). The spheres of lipids were arranged like strings of pearls of different length throughout the entire digestive gland of a larva caught in February 1989 during the phytoplankton bloom.

The outer surface of the deutoconcha was also tested for the presence of lipids, but was found to lack them. This test was repeated on another larva that had been caught prior to the beginning of the phytoplankton bloom (mid-November 1986). It lacked lipids in either the man- tle or the digestive gland.

Of the other organs of the larva, the nerve ring proved to be quite large. The eyes were well-developed, with lens-like light collectors. The foot is intensely ciliated, almost to the same degree as the large velum. The radula is well developed and functional.

Observations with Electron Microscope

The epidermis of the deutoconcha (figure 11) is covered by a 2 ^m high rim of microvilli. These microvilli are differentiated into a narrow basal portion with many filaments and a light, partly bubble-like expanded upper portion.

These "bubbles" are secretory vesicles, usually linearly arranged and attaining 2-4 times the width of the mi- crovilli. They are produced by glandular cells at the base of the rim of microvilli and are secreted at the outside of the rim. "Bubbles" open up at the outside of the rim as could be seen in some sections.

The surface of the rim of microvilli is covered with fine fibrillar material containing small dark granules.

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THE NAUTILUS, Vol. 107, No. 1

Between microvilli, larger vesicles with a small internal membrane are often present. Some larger vesicles are as high as the microvilli and are connected to the glandular vesicles of the epidermis.

The epithelium of the deutoconcha consists of a single layer of flattened cells resting on a distinct basal mem- brane. The cells are up to 10 ^m in size, and are con- nected to each other by apical contact zones. Cell bound- aries are strongly folded and intercalated.

Some nuclei are strongly heterochromatic, others are large, less densely packed and of irregular shape. All cells hold large, light vesicles often containing membranous extensions. These vesicles form a loosely connected sys- tem that is in contact with the vesicles extruded into the rim of microvilli. Newly extruded vesicles hold dense granules.

A voluminous connective tissue is present below the epidermis and fills the space between inner and outer layer of the deutoconcha. Within a homogeneous basal substance, individual, transversally striped fibers of col- lagen connect the basal membrane of cells within the tissue to the epidermis.

Large cavities lie within the connective tissue near the epidermis. These cavities are lined with a thin, conspic- uously foamy cellular layer resting on a basal membrane. The nuclei are flattened and elongated.

Nerves, consisting of several axones within a glial cell, and smooth muscular fibers with connections to the col- lagen fibers are distributed within the connective tissue.

The intermediate layer between outer and inner ep- ithelia (gelatinous layer, Simroth, 1908) is shown to con- tain a network of collagenous fibers connected to muscle and epithelial cells. This layer functions together with interconnected blood lacunae as a hydroskeleton that can change the outline, shape and width of the limacos- phaera.

The apical tube (figures 4, 10, st) of the deutoconcha is ciliated, in contrast to the remaining surface of the mantle. This ciliation continues into the small cavity at the proximal end of tube above the shell. This cavity is less extensive than assumed by Simroth (1908) and does not surround the entire shell surface.

Simroth (1908) noted a folded surface of the shell, which is an artifact of preservation.

A rim of microvilli on a unilayered epithelium sur- rounding a structured connective tissue represents a large surface for resorption as well as for secretion by many glandular cells that come together in canals opening into pores. The type of secretion produced by these glands is unknown. The secretion expelled between the microvilli probably represent neutral mucus material.

DISCUSSION

The larvae metamorphosed into juveniles that had either a smooth surface or a tuberculated body surface. Both juvenile forms were analysed by gel-elect rophoresis (ID- UISK-SI)S-PA(;E) at the Alfred-Wegener-in.stitut (Dr. T. Stadler). The results were compared to gel-electro-

Bum

cb

Figure 11. Transmission Electron Micrograph of the deuto- concha epidernii.s of Marscniopsis cf. mollis, bm, ba.sal mem- brane; ci), cell boundary; ct, connective tissue; mv, microvilli; n, nucleus.

phoresis (same method) analyses of adult Marseniopsis conica and Marseniopsis mollis. Differences in the data indicate that the predominantly smooth juveniles re- present M. mollis and the tuberculated ones M. conica. I'hus it can be concluded that both species have very similar larvae. It was not possible to section and electro- phoretically analyse the same individual.

The course of a limacosphaera's development depends on a variety of factors, including currents in the upper water layers, melting of sea ice, and patchyness of phy- toplankton production. Larval survival in captivity for 1.5 years indicates that a limacosphaera could remain in the plankton for over a year if conditions were not fa- vorable for metamorphosis.

Analyses of lipid content suggest that larvae either use most food-energy for growth or they store energy in form of other biochemical metabolites {e.g., proteins). The vertical distribution and the stomach contents of larvae caught during mid-October at 72°S indicate that they feed under the sea ice where the phytoplankton concen- tration (0.07 ng chl- a/liter) was seven times larger than in deeper water (Scharek, personal communication). Due to the southwcsterK water currents near the surface, the majority of larvae will be transported to southern parts of the study area, where very high phytoplankton con- centrations (50-150 ^g chla/liter) were measured di- rectly under the sea ice in October 1989. By utilization of this enormous food resource, larvae living in that area could grow very rapidly. Due to the fact that the macro- zoobenthos community of the southern Weddell Sea is totally different from that of the eastern Weddell Sea (Voss, 1988) and therefore not suitable for survival of beiithic stages of Marseniopsis, there nuist be a way of

K. Bandel et al., 1993

Page 7

returning pelagic stages (metamorphosing larvae, juve- niles or adults) back to the hatching grounds. This may be accomplished by counter-currents nuining near the bottom.

Piatkowski (1987) and Boysen-Ennen (1987) reported the absence of larvae in the oceanic domain between the tip of tlie Antarctic peninsula and the north-eastern part of the Weddell Sea. Marseniopsis populations of the peninsula are likely zoogeographically separated from populations in the eastern Weddell Sea. Nevertheless some of the larvae could be transported by eastward wind drift ot surface water layers near the ice edge from eastern-Antarctica to the Weddell Sea. Between Feb- ruary and March 1983, the mean abundance of larvae in the eastern Weddell Sea was 24 specimens per 1,000 m' (Boysen-Ennen, 1987), with maximum densities of 65 larvae per 1,000 m' in the southern part of the study area (Piatkowski, 1987). Most larvae were found in water layers of 200 to 50 m (63%) and 50 to 0 m (35%), only 2% were reported from 300 to 200 m depth (Boysen- Ennen, 1987). The major function of the deutoconcha is that of a buoyancy organ. Altering the volume of the outer mantle may vary the speed of sinking of the li- macosphaera. According to Stokes formula (Tiemann & Betz, 1979) this speed depends on the specific weight, which again is a function of the diameter of the lima- cosphaera. Histological analyses of the limacosphaera showed that the deutoconcha contains very little organic material and is thus very close to the density of sea water. The deutoconcha can enlarge the diameter and thus the volume of the larva without decreasing its weight in the water. A general calculation indicated that the volumi- nous outer mantle of the limacosphaera decreases the speed of its sinking to about one half of what it would be without such a cover around the shell

The ability to float was observed in aquaria for all developmental stages. Even large adult specimens could float near the bottom after disturbance (diving obser- vations at the Antarctic peninsula, W. Wagele, personal communication).

The function of the deutoconcha's apical tube and cavity is still unknown. It is evident that water can be pumped into the cavity and expelled out by ciliary cur- rents as well as by muscular movements of the deuto- concha. It is also evident that glands can secrete sub- stances into the lumen of tube and cavity.

Histological examination of the limacosphaera for the most part confirms the observations of Simroth (1908, 1914). His assumption that muscular cells are present within the deutoconcha is substantiated.

The prolific mucus secretion of the entire deutoconcha, as well as its large size may serve as defensive mechanisms against carnivorous planktonic groups like copepods or krill.

The shell size of hatching larvae can only be inter- preted from the embryonic and the larval shell (figure 8). There are two possibilities. The normal case would be that the embryo hatches shortly after the Ijeginning of growth lines (the mantle becomes free from the shell)

(figure 9, arrow). This happens after 0.8 whorls and a diameter of the shell of 0.65 mm.

The second possibility is that the embryo does not hatch before reaching 1.4 whorls (with spiral threads). The shell then has a diameter of 1.5 mm. To reach this size the embryo v\ould have to feed on extra yolk.

It is proposed that the embryo hatches when the shell has reached 1.4 whorls. At this time tlie spiral threads disappear. This is probably the consequence of the man- tle fusing above the shell. There is no difference in sculp- ture between the subsequent part of the larval shell and the teleoconch of the investigated species of Marseniop- sis.

ACKNOWLEDGEMENTS

Tliis study was carried out with financial support of the Deutsche Forschungsgemeinschaft (DFG) in the frame of the Antarctis-research grant and science grant Ba 675/ 6-1 We have been greatly aided by our colleagues of the Alfred-Wegener-Institut (Brenierhaven), Zoological and Geological-Paleontological departments of the Uni- versity of Hamburg. We are grateful to Dr. T. Stadler who carried out the gel-electrophoresis analysis. Dr. M. G. Harasewych greatly improved st\le and grammar of the manuscript.

To all persons and institutions involved, we express our sincere thanks.

LITERATURE CITED

Adam, H. and G, C^lzihak 1964 Arbeilsniethoden der mak- roskopischen Anatomie. Ein Laboratoriumshandbuch fiir Biologen, Mediziner und technische Hilfskrafte. Gustav Fischer Verlag, Stuttgart, 583 p.

Boysen-Ennen, E 1987 Zur Verbreitung des Meso- und Mak- rozooplankton.s im Oberflachenwasser der Weddell See (Anlarktis) Berichte zur Polarforschung 35:1-126

Fretter, V. and A, Graham. 1962. British prosobranch mol- luscs. Ray Society, London. 7.55 p.

Hagen, W. 1988. Zur Bedeutungder Lipide im antarktischen Zooplanktnn. Berichte zur Polarforschung 49:1-129

Jevdonin, L. A. and J. S. Minichev. 1975. Adaptations of pelagic gastropods. Malacological Review 11:75

Mileikovsky, S. A. 1971. Types of larval development in ma- rine bottom invertebrates, their distribution and ecological significance: a re-evahiation. Marine Biology 10:193-213.

Pelseneer, P 1903 Resultats du vo\age du S Y. "Belgica" 1897-1899. Rapports Sci. Zoologie, Mollusques (Amphi- neures, Gasteropodes et Lamellibranches) Anvers, 85 p.

I'lalkovvski, L'. 1987. Zoogeographische Untersuchungen und Gemeinschaftsanalysen an antarktischem Makroplankton. Berichte zur Polarforschung 34:1-138.

Picken, (; B 1980. Reproductive adaptations of Antarctic benthic invertebrates. Biological Journal of the Linnean Society 1467-75.

Ronieis. B. 1968. Mikroskopische Technik. Oldenbourg Ver- lag, Mijnchen, 16. .\uOage, 7.57 p.

Simroth, H. 1908. Gastropodenlaiche \ind Gastropodenlarven der Deutschen Tiefsee-Expedition In: C Chun (ed). Wis- senschaftl Ergebnisse der Deutschen Tiefsee-Expedition

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auf dem Dampfer -Valdivia' 1898-1899, Band IX:365- Tiemann, H and K -H Bctz 1979 Elutriation: theoretical

,,Q considerations and methodological improvements Marine

Simroth H 1914. Pelagische Gastropodenlarven der deut- ecology. Progress Series 1277-281.

schen Siidsee-Expedition 1901-1903. /;i: Drygalski, E.v Voss, J. 1988 Zoogeographie and Gemeinschaftsanalyse des

(Hrsg.). Deutsche Sudpolar-Expedition, Zoologie Band VII Makrozoobenthos des Weddellmeeres (Antarktisj. Berich-

15143-160. ''' ^"'' Polarforschung 45:1-14.5.

THE NAUTILUS 107 1 9-13. 1993

Page 9

The Reproclucti\ e Anatom\ of Philomijcus sellatus Hubricht. 1972 and Philomijcus virginicus Hubricht. 1953 (Gastropoda: Philom\cidae)

H. Lee Fairbanks

Penns\l\ ania State Universits- Monaca. PA 15061 USA

ABSTRACT

Specimens of Philomycus sellatus and P virginicus were col- lected at or near their t> pe localities. Their reproducti\ e anat- om\ is described and compared with that of other species of Philomycus. The penial anatom\ of P sellatus is unique in ha\ing two constrictions in the penial wall; P virginicus is distinguished by a circular pustulose ridge that separates the distal penis from its atrial opening.

Key Words: SloUusca; Gastrojxxla; landsnail: slug; Philomy- cldap: Philornvcj'- reproductive anatomy

LVTRODUCTION

.\1] species of the terrestrial slug family Philomycidae ha\e a mantle that co\ers the entire bod> of the slug. Three genera of this family. Philomycus. Pallifera. and Megapallifera. occur in the United States, with most species being limited to the eastern and south-central areas of the country . Few original descriptions pro\ide anatomical data. Neither the description of Philomycus virginicus Hubricht. 195.3 nor of P. sellatus Hubricht, 1972 discusses or figures an> part of the reproductive anatomy. Based up>on the mande pattern. Hubricht 19721 compared Philomycus sellatus to P ccirolinianus Bosc. 1S02!. but made no comparisons between P. virginicus and other species of Philomycus. References to the re- producti\e anatomy of P. virginicus are limited to two articles by Branson il96S. 1969; that compared P. vir- ginicus with P. bisdosus Branson. 196S. Neither contain figures or measurements. The reproductive anatomy of P. sellatus has not pre\iousl\- been studied.

The goals of the present study were to describe the anatomy of the reproductive systems of Philomycus vir- ginicus and P. sellatus. and to compare them with those of other sp>ecies of Philomycus.

METHODS AND MATERI.ALS

Sf)ecimens of Philomycus virginicus were collected on 19 May 19S9 near nulepost 47 north of Skyline Drive. Shenandoah National Park, Madison County , \irginia.

under the loose bark of logs and dead trees, eleiation appro.ximately 1110 meters. This station was approxi- mately O.S kilometers east of the tvpe locafity for this species. Specimens of P. sellatus were collected on 17 May 19S9 from its t>p)e locahty (2.7 kilometers northeast of Princeton, along Highwa> 65. Jackson County . .Ala- bama; in beede galleries in rotten logs, elevation ap>- pro.ximateK 215 meters. For comjjarative purposes, the following sp>ecie5 were also e.xamined: P. carolinianus collected in Berkele> Cotmty . South Carolina approxi- mateK 2-5 kilometers from Charleston, the designated t>pe iocaht) ,Pilsbry, 1945:754; on 22 June 19SS; P. bisdosus collected from Breaks Interstate Park. Dick- enson Coimty. Virginia the type locahty on 22 May 1987: P. flexuolaris collected from Breaks Interstate Park, Dickenson County. Virginia on 22 Ma> 1987: and P. togatus collected near Riceville. PittsyKania County, Virginia on 20 May 1987.

External characteristics of the specimens were com- pared with the original sp)ecies descriptions to ensure correct identification. All specimens were drowned in distdled water and dissected immediately. The repro- ducti\ e sy stems were removed and the atrium and penis opened to examine their internal anatom\ . Subsequendy all material was preserved in 70"^ ethanol. DrowTiings and dissections were conducted during the month of Jvme in each > ear to reduce any differences that may be at- tributable to the stage of the life c>cle. The sjjecimens were maintained in terraria for approximately two weeks prior to dissection.

E^ch complete reproductive system was spread out in a f)etri dish and then projected- \ia an overhead projector, and traced. The p>enial figures are tracings of photo- graphic shdes of the opened organs. Voucher sp>ecimens have been deposited in the Academ\- of Natural Sciences, Philadelphia ANSP .Al>326 for Philomycus bisdosus, .ANSP A1S327 for P virginicus. ANSP A13328 for P. sellatus, and .ANSP Al-3329 for P. carolinianus}.

RESULTS

Four adult specimens each of Philomycus sellatus and of P. virginicus were collected and used in the studv.

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/

Figures 1-4. Mantle patterns of living slugs. 1, 2. Philomtjcus virginicus 3, 4. Philomtjcus sellatiis. Scale bar = 20 mm.

External characteristics of all four specimens of each species (figures 1-4) agreed with their type descriptions. The gross reproductive anatomy was similar for all spec- imens of a species. Measurements of selected reproduc- tive organs are shown in Table 1.

Genitalia of Phibmycus sellatus Hubricht, 1972 (figures 6, 8)

Atrium glandular on distal half of outer surface, length approximately 60'/o penial length. Vagina length ap- pro.ximately 10% of penis. Spermathecal duct approxi- mately same diameter as free oviduct, length nearly twice that of free oviduct, slight taper toward spermatheca. Spermatheca round. Dart sac (with dart) larger than spermatheca. Penis diameter at proximal end nearly equal to atrial diameter, gradual taper to diameter of vas de- ferens at distal end; penial sheath covers approximateK

Figures 5, 6. Genitalia, 5. Philornycus virginicus. 6. Philo- mtjcus sellatus. Scale bar = 10 mm. A: atrium, AG; albumen gland, AR: accessory retractor, DS: dart sac, FO: free oviduct, G: gonad, GP: genital pore, HD; hermaphroditic duct, P: penis, PR: penial retractor, S: spermatheca, \': vagina, \'D: vas de- ferens.

90% of penis. InternalK , distal third of penis with several thin low folds, separated from remainder of penis by constriction in penial wall; middle third with 3-4 large pustulose ridges; proximal third with several thin non- pustulose folds, separated from middle third b\ constric- tion in penial wall. Vas deferens enters distal end of penis, length approximately four times that of penis; diameter of middle third half that of ends. Penial retractor muscle maximum width 2-3 times diameter of distal end of penis, length 40% of penis. Accessory retractor muscle present, located on outer wall of atrium near its junction with penis.

Genitalia of Philornijcus virginicm Hubricht, 1953 (figures 5, 7)

Atrium length approximately equal to that of penis, ex- ternal surface of distal half glandular. Base of penis bulg- es into atrium. N'agina short, approximateK 15% of penial length. Spermathecal duct diameter greater than that of free oviduct, slight taper toward spermatheca. Sperma- theca round. Dart sac (with dart) smaller than sperma- theca. Penis straight, basal diameter one third of length, slight taper to junction with vas deferens; penial sheath reaches to junction of penis with vas deferens. Internally,

H. L. Fairbanks, 1993

Page 11

Figures 7, 8. Internal penial anatomy. 7. Philomycus virgin- iciis. 8. Philomycus setlatus. Scale bar = 10 mm. Cut surfaces indicated by oblique lines in all drawings. A; atrium, DS: dart sac, P: penis, PR: penial retractor, PS; penial sheath, VD: vas deferens.

penis with 4-6 pustulose ridges, a basal pustulose circular ridge sets off distal parts of the penis from its opening into the atrium. Vas deferens encircles distal end of penis, entering penis terminally. Vas deferens length approxi-

Figures 9, 10. Genitalia 9. Philomycus bisdosus. Scale bar = 10 mm. 10. Philomycus carolinianus. Scale bar = 5 mm. A: atrium, AG: albumen gland, .\R accessory retractor, DS: dart sac, FO: free oviduct, G: gonad, GP: genital pore, HD: her- maphroditic duct, P: penis, PR: penial retractor, S: spermathe- ca, V: vagina, YD: vas deferens.

mate!) 3.3 times that of penis, approximately same di- ameter throughout its length. Penial retractor muscle maximum width one third that of diameter of distal end of penis but broader at its distal end, length approxi- mately one third that of penis. Accessory retractor muscle absent or not distinguishable from typical connective tissues.

Table I. Measurements (mm) of selected reproductive organs of species of Philomycus. Means with std. deviation and ranges are

	P. sella t us (4)*	P. virginicus (4)*	carolinianus (5)*	P. bisdosus (2)*	flexuolaris (2)*	P. togatus (2)*
Length of penis	13.1(1.82) 11.0-14.2	5.8 (0.66) 5.4-6.8	6.0(0.61) 5.4-7.0	7,1 (0,00) 7.1	7.3 (0.35) 7.0-7.5	12.9 (2.33) 11.2-14.5
Diameter of penis (atrial end) Length of vagina	4.4(0.49) 4.1-5.0	3.7(1.07) 2.7-5.0	2.2(0.29) 1.9-2.7	3.0 (0.07) 2.9-3.0	2.8(0.64) 2.3-3.2	3.3 (0.42) 3.0-3.6
1.2(0.15) 1.0-1.3	0,8 (0.29) 0.5-10	1,5(0,41) 1.1-2.2	1.1 (0.49) 0.7-1.4	1.6(0.35) 1.3-1.8	3.1(1.70) 1.9-4.3
Length of free oviduct	8.8(1.50) 7.8-10.5	10.2(1.87) 8.9-12.9	7.7(1.44) 6.2-10.0	7.6(0.62) 6.9-8.1	7.6 (0.64) 7,1-8.0	7.2(0.28) 7.0-7.4
Length of \as tleferens	57.5(4.77) 52.0-60.5	21.1 (2.11) 1 8 8-23 0	38.1 (4.96) 33,8-45,1	19.1 (1.02) 17.9-19.8	24.2 (3.04) 22 0-26 3	34.0(0.71) 335-345

* Number ot specimens measured.

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THE NAUTILUS, Vol. 107, No. 1

Figures 1 1, 12. Internal penial anatomy. 1 1. Philomyctis bis- dosus. Scale bar = 10 mm. 12. Philomycus caroliniantis. Scale bar = 5 mm. A: atrium, DS: dart sac, P: penis, PR: penial retractor, PS: penial sheath, VD: vas deferens.

DISCUSSION

When Hubricht (1972) described Philomycus sellatus, he noted that, based upon the posterior half of the mantle, it ". . .is most closely related to P. carolinianus (Bosc).", with which "It sometimes occurs. . .". However, the black transverse band near the anterior end of the mantle of F. sellatus (figures 3, 4), which is not present on P. carolinianus (Pilsbry, 1948 p. 748), easily separates the two species in the field. Their reproductive systems (fig- ures 6, 10) are also distinct. The shape of the penes and their internal anatomies (figures 8, 12) are clearly dif- ferent, Philomycus carolinianus lacks the two internal constrictions in the penial wall that are found in P. sel- latus, and the internal penial pilasters are smaller and more numerous in P. carolinianus than in P. sellatus. Additionally, the penis and vas deferens of P. sellatus are nearly twice as long as those of P. carolinianus (Table 1). Indeed, the black anterior transverse band on the mantle and the two constrictions in the penial wall are characteristics unique to P. sellatus.

Hubricht (1953) noted that Philomycus virginicus was found associated with P. flexuolaris (Rafinesque, 1820) and P. togatus (Gould, 1841) (as P. carolinianus collinus

in Hubricht's 1953 article). Among these ta.\a, only P. virginicus has the transverse chevron pattern on the man- tle (figures 1, 2) and is thus easily separated from the others in the field. In addition, measurements of the reproductive systems of P. flexuolaris and P. togatus demonstrated several differences from that of P. virgin- icus (Table 1). The penis and vagina of P. virginicus are shorter than those of P. flexuolaris; the free oviduct of P. virginicus is much longer than that of P. flexuolaris. Philomycus togatus has a much longer penis, vagina, and vas deferens than P. virginicus; the free oviduct of P. virginicus is longer than that of P. togatus (Table 1). Branson (1968), in reference to P. virginicus and P. bisdosus (figures 5, 9), stated that "The genitalia of the two species also differ.", but no figures nor measurements were included. Branson (1969) listed some differences between the reproductive anatomies of these latter two species, but again without figures or measurements. Fig- ures 7 and 11 show clearly the differences in the shape of the penis and the internal penial anatomy of these two species, and the free oviduct of P. virginicus is nearly 1.5 times the length of the P. bisdosus oviduct (Table 1 ). In addition, P. bisdosus lacks the anterior to posterior transverse chevrons on the mantle. Comparisons with previous studies of reproductive anatomv in species of Philomycus (Fairbanks, 1986, 1989; Pilsbry, 1948) con- firmed that the internal surface of the penis of P. vir- ginicus is unique in having a basal circular pustulose ridge at the atrial end.

ACKNOWLEDGMENTS

Financial support for the field trips associated \\ ith this study was provided by grants from the Research De- velopment Grant Fund of The Pennsylvania State Uni- versity. My thanks go to three anonymous reviewers who provided valuable suggestions for improving this article.

LITERATURE CITED

Bosc, L. A. G. 1802. Histoire naturelle des coquilles. Conten- ant leur description, et leurs moeurs. \'ol. I. Paris, 343 p., Ipl.

Branson. B. A. 1968. Two new slugs (Pulmonata: Philomy- cidae: Philomycus) from Kentuck\ and X'irginia. The Nautilus 81(4):127-133.

Branson, B. A 1969. Genital differences in Philomycus vir- ginicus Hubricht and P bisdosus Branson. The Nautilus 82:74,

Fairbanks, H. L. 1986. The taxonomic status of Philomycus togatus (Pulmonata: Philomycidae): a morphological and electrophoretic comparison with Philomycus carolini- anus. Malacologia 27(2):271-280,

Fairbanks, H, L. 1989, The reproducti\e anatoms and tax- onomic status of Philomycus vcniislus Hubricht, 1953 and Philomycus bisdosus Branson, 1968 (Pulmonata: Philo- mycidae), The Nautilus 103(I):20-23,

Gould, A, A, 1841. Report on the invertebrates of Massachu- setts, comprising the MoUusca, Crustacea, Annelida and Radiata, vol. 3.

H. L. Fairbanks, 1993

Page 13

Hubricht, L. 1953^ Three new species of Philomycidae^ The Nautilus 66(3):78-80.

Hubricht, L. 1972, Two new North American Puimonata: Paravitrea seradens and Philomycus sellatus^ The Nau- tilus 86(1):16-17.

Pilsbry, H. A. 1948. Land MoUusca of North America (North

of Mexico). The Academy of Natural Sciences of Phila- delphia Monograph Number 3, Vol, II Part 2:759. Rafinesque, C. S. 1820. .Annals of Nature or annual synopsis of new genera and species of animals and plants discovered in North America, p. 10.

THE NAUTILUS 107(l):14-23, 1993

Page 14

Two Confusing Indo-Pacific Cerithiids

Richard S. Houbrick

Department of linertebrate Zoology National Museum of Natural History Smithsonian Institution Washington, DC. 20560

ABSTRACT

Cerithium zebrum Kiener, 1841 and Cerithium boeticum Pease, 1860. although originally described as CerUhiiim species, had been allocated to Bittium Gray, 1847, in the recent literature Anatomical investigation has shown that these two species do not have the characters of Bitlium species, but are are more like Cerithium taxa, e.xcept for their small size. Cerithium zebrum is distinguished from Cerithium boeticum. based on morphological characters derived from the shell, radula and soft anatomy. Synonymies, descriptions and a discussion of the differences between the species are presented.

Key Words: Cerithium, Bittium, morphology, anatomy, tax- onomy.

INTRODUCTION

Small-shelled cerithiids are difficult to identify to the species-level, particularly poorly-known taxa from the Indo-Pacific region. Generic and sometimes familial de- terminations of these small snails are likewise difficult and controversal, and in most museum collections many small-sized cerithiids are grouped together and loosely attributed to the genus Bittium Gray, 1847.

During a recent generic review of the Bittium-gToup the anatomy of a number of "Bittium" species were examined. One of the taxa studied is "Bittium" zebrum (Kiener, 1841), a common species throughout the Indo- Pacific region that is extremely variably in sculpture and color pattern. As expected in a common, widely-distrib- uted species comprising many sculptural phenotypes and color morphs," Bittium ' zebrum has been zealously ov- ernamed by authors, as a perusal of its synonymy will testify.

When living "Bittium" zebrum specimens from Guam, Enewetak, and Hawaii were examined it was discovered that none of these snails had an epipodial skirt, charac- teristic of members of Bittiinae. Moreover, there was no spermatophore bursa present in the lateral lamina of the pallial oviduct, a feature distinctive of the Bittium-group. These animals are thus transferred from Bittitim to Cer- ithium Briiguiere.

Further comparison of the Hawaiian specimens of

"Bittium" zebrum with those from other Indo-Pacific regions revealed that there are considerable morpholog- ical differences between the populations: the shells, rad- ula and anatomy of the Hawaiian specimens are quite distinct from those of zebrum specimens from elsewhere. Subsequent careful examination of many museum lots of Cerithium zebrum revealed that most lots of Hawaiian specimens comprised mixtures of two species: the first having a typical zebrum phenotype, and the second, more common, species having a different shell physi- ognomy. It became apparent that the second species is Cerithium boeticum Pease, 1860, named from the Ha- waiian Islands and subsequently considered to be con- specific with "Bittium" zebrum by Kay (1979).

This paper addresses the differences between the two species, describes and presents a s\ nonymx of each, and delineates the characters separating and distinguishing them. Cerithium boeticum is recognized as a valid spe- cies, different from Cerithium zebrum, and is shown to be endemic to the Hawaiian Islands.

MATERIALS AND METHODS

Living specimens of Cerithium zebrum were studied at Enewetak Atoll, Marshall Islands, and at the L^niversity of Guam Marine Laboratory at Pago Bay, Guam. Cer- ithium boeticum was collected from shallow, subtidal coral rubble in Kewalo Basin, Honolulu, placed in aquar- ia and observed at the Kewalo Laboratorx of the Ha- waiian Biomedical Research Laboratory, University of Hawaii, Honolulu, Hawaii. Both species were observed and dissected under water in wax-filled petri dishes using a Wild M-5 dissecting microscope. Methylene blue was used to enhance anatomical features during dissection. Protoconchs, shells, opercula and radulae were studied with an Hitachi S-570 scanning electron microscope. The types of both species and their synonymous nomina were examined and are discussed below. Man\- museum lots were examined in order to establish the range of phe- notypic variation in the shells of each species. Measure- ments and meristic data of shells were taken using ran- domly selected specimens from locations throughout the geographic range of each species.

R. S. Houbrick, 1993

Page 15

Material examined: Cerithiitm hocticum. HAWAIIAN ISLANDS: (USNM 343522); Oaliu (USNM 12916, types); Honolulu, Oahu (USNM 335496, 335499, 335497, 335498, 767506); Waikiki Marine Lab, Honolulu, Oahu (USNM 633002); Kewalo Basin, Honolulu, Oahu (USNM 857099); Honolulu Reef, Oahu (USNM 335289); Quarantine Is- land, Honolulu, Oahu (USNM 339349, 339342); Waikiki, Oahu (USNM 343514, 343515, 343519); off Waikiki, Ho- nolulu, Oahu (USNM 339118); Kewalo Basin, Honolulu, Oahu, Hawaii (USNM 857099); Diamond Head, Hono- lulu, Oahu (USNM 339339, 343510); Mokapu Beach, Oahu (USMN 484570); Maunalua Beach, Oahu (USNM 428173, 428174, 428207, 343520, 343511); Mokoloe Is- land, Oahu (USNM 339343, 343512); Kaneohe Bay, Oahu (USNM 472057, 472058, 343513); Coconut Island, Ka- neohe Bay, Oahu (USNM 771362, 771556); Hospital Point, Pearl Harbor, Oahu (I'SNM 497938); Pearl Harbor, Oahu (USNM 484455, 428234, 341308); Pupukea Beach, Oahu (USNM 484689); Kahana Bav, Oahu (USNM 777967); Kahala, Oahu (USNM 33951, 339928); Kahala Beach, Koko Head, Oahu (USNM 343546); Keoke River, Hawaii (USNM 252339, 252338, 252336); Keokea, Hawaii (USNM 337592); Keokea, Hilo, Hawaii (USNM 339340, 339340); Hilo. Hawaii (USNM 612281); Kuhio B., Hilo, Hawaii (USNM 339125); Honaunau, Hawaii (USNM 343517); 5 mi SW Kapoho, Hawaii (USNM 409081, 409095); Lanai (USNM 612425); Mauele, Lanai (USNM 339341); Han- alei, Kauai (USNM 340692); Midway Island (USNM 790897, 790898); Frigate Point, Sand Island (USNM 678064).

Cerithiumzebriim. MAURITIUS: (USNM 91247, 91069, 91070); Flicq-en-Flacq, Arsenal Bay (USNM 716523). SEYCHELLES: Aldabra Atoll, lie Picard (USNM 837490). COCOS (KEELING) ISLANDS: Alor Pinvu, NW side of West Island (USNM 656435). AUSTRALIA: Heron Is- land, Queensland (USNM 8540174); Watson's Bav, Liz- ard Island, Queensland (USNM 783381). RYUKYU IS- LANDS: Osima, Osumi (USNM 343873); Odomaria, Okinawa, Shima (USNM 488199); Yenoshima (USNM 228222); Chichyima, Ogasawara (USNM 175587). BO- NIN ISLANDS: '(USNM 36950, 343874). PHILIPPINES: Jamelo Bav, Luzon (USNM 935351). MARIANAS: Saipan (USNM 486824, 486823, 486795); Guam (USNM 851 104, 851104); Pago Bay, Guam (USNM 774778); Apra Bay, Guam (USNM 240110); Orote Point, Orote Cliffs, Guam (USNM 854036). CAROLINES: Moen Island, Truk La- goon (USNM 842615); Reef at Mutunlik, Kusaie Island (USNM 609487). LOYALTY ISLANDS: (USNM 253564); Lifu (USNM 423278, 423260, 423210, 423282, 423281, 423261, 423325, 423283). FIJI: Rat Tail Passage, Suva Reef (USNM 824808); SAMOA: Pago Pago (USNM 361535, 361536); Ofu, Manu'a Group (USNM 380968, 380965, 380967, 380969, 380962, 380963, 380960, 380966). MARSHALL ISLANDS: Enewetak (USNM 432415, 770725, 542726); Rennit Island, Enewetak (USNM 542809); Fred, Enewetak (USNM 770687); Aa- raanbiru Island, Enewetak (USNM 582227, 582265); Tei- teiripucoki Island, Enewetak (USNM 581543); Girunien Island, Enewetak (USNM 581534); Engebi Island, Enew-

etak (USNM 743869); Rijoru Island, Enewetak (USNM 581555); E. Rigili Island, Enewetak (USNM 581923); between Rigili and E. Rigili Islands (USNM 581576, 581575); Ailuk Island, Ailuk Atoll (USNM 615133); Lae Island, Lae Atoll (USNM 614896); Bock Island, Rongerik (USNM 594660); Enwertok, Rongerik (USNM 583519); 4 mi. W Bikini Islands (USNM 586086); Bikini (USNM 583949, 585185); Bokororvuru, Bikini (USNM 583883, 583884); Namu Island, Bikini (USNM 580542); Enyu Island, Bikini (USNM 580945); Eninman Island, Bikini (USNM 586897); Pigenivarayro, Rongelap (USNM 585588, 585327); Kabelle Island, Rongelap (USNM 582405, 582388, 582125, Burok, Rongelap (USNM 583989); NIUE: Opaahi, S. of Alofi (USNM 854054); Alofi (USNM 854046); Tuapa (USNM 858164); Tuapa, Avaiki Cave (USNM 854055). COOK ISLANDS: Mauke Island (USNM 598174). SOCIETY ISLANDS: Reao Id (USNM 5573, holotype); Makatea, Tuamotu Archipelago, N Ti- mae Harbor (USNM 819895); Arue, Papeete, Tahiti (USNM 775927); Mahina, Tahiti (USNM 797267, 791372); Tahiti (USNM 91068). WALLIS & FUTUNA ISLANDS: outer reef E of Nukuhifala (USNM 676427); Henderson Id (G. Pauley coll.). NIUE: off warf, Alofi (USNM 854046); Avaiki Cave, Tuapa (USNM 854055); Tuapa (USNM 858167); Opaahi, S Alofi (USNM 854054). HAWAII: French Frigate Shoals (ANSP 195368, 195384); Midway (USNM 790897); Honaunau, Hawaii (USNM 343509); Keokea, Hilo, Hawaii (USNM 339353).

Abbreviations: BMNH = British Museum (Natural His- tory); MNHNP = Museum National d'Histoire Naturelle, Paris; NMW = National Museum, Wales; SEM = scan- ning electron microscope; USNM = United States Na- tional Museum, Smithsonian Institution, Washington, DC.

RESULTS

Descriptions (Tables 1 & 2, Figs. 1-28), synonymies, and discussions of both species are presented below, followed by a table identifying the characters separating the two species (Table 3).

Cerithium zebrum Kiener, 1841

Cerithium zebrum Kiener, 1841:71, pi. 25, fig. 4 (holo- tvpe, MNHNP; type locality, Indian Ocean, Mauritius). Sowerbv, 1855:875-876, pi. 183, figs. 207-209; 1865, pi. 19, fig. 136; Tryon, 1887: 138, pi. 26, figs. 78-82; Kobelt, 1898:210-211, pi. 39, figs. 7-10; Hedley, 1899:434; Vignal, 1903:21-22, pi. 2, fig. 1; Schepman, 1909:162; Dautzen- berg & Bouge, 1933:313.

Cerithium janlhinum Gould, 1849:121 (holotype, USNM 5573, 8.5 X 3.9 mm; type loclaity. Clermont Tonnere [Reao Id, Tuamotusj; 1852:152, pi. 10, fig. 173a-b; 1862:63; Johnson, 1964:95.

Cerithium zebrum var. dilectum C.B. Adams in Sowerby, 1855: 896, pi. 33, fig. 207' (15 syntypes, BMNH 1969349; type locality, Galapagos [in error]); Vignal, 1903:22-23, pi. 2, fig. 5. ■

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R S. Houbrick, 1993

Page 17

Figs. 16-17. Scanning electron micrographs of radula of Cerithium zebrtim Kiener, Pago Bay, Guam (USNM 774778); 16. view of mid-section of radula, bar = 36 ^m; 17. half row showing details of rachidian, lateral and marginal teeth, bar = 29 ^m.

Cerithium delectum (sic) A. Adams. Sowerbv, 1865, pi 16, fig 112 a-c; Vignal, 1903:23.

Cerithium unilincatum Pease, 1860:432 (lectot>pe, BMNH 19622798, 5.5 x 3 mm, 2 paralectotypes BMNH 1962799; t\ pe locality. Sandwich Ids [Hawaiian Ids]). Sowerbv, 1866, pi. 15, fig.99; Trvon, 1887:138, pi. 26, fig. 86; Kobelt, 1898: 224, pl.29, fig. 18.

Cerithium stigmosum Gould, 1861:386 (holotype, ?; type lo- cahty, Bonin Ids) 1862:141; Johnson, 1964:152.

Cerithium aspersum Deshayes, 1863:97-98, pi. 11, figs. 16-18 (lectotype, here selected, MNHNP, 8.8 mm, 4 paralecto- types, MNHNP; type locality. Reunion).

Cerithium Crossii Deshayes, 1863:96, pi. 11, figs. 12-14 (lec- totype, here selected, MNHNP, 8.4 mm, 3 paralectotypes, MNHNP; type locality. Reunion; not Cerithium cros- seanum Tiberi, 1863 [= Cerithioipsis sulwylindricum (Brusina)], nor Cerithium maillardi Crosse, 1863 [unnec- essary replacement name for Cerithium crosseanum Ti- ber!].

Cerithium dichroum Melvill is. Standen, 1895: 115, fig. (6 syn- types NMW 55158200; type locality, Lifu, Lo\aity Idsi

Cerithium zebrum var. pulchra Vignal, 1903:22, pi. 2, fig. 2 (t>pe, MNHNP; type localit> , Isle of Pines, New Cale- donia); Dautzenberg & Bouge, 1933:315.

Cerithium zebrum var. trijasciata N'ignai, 1903:22, pi. 2, fig.

3 (type, MNHNP; type locality. Isle of Pines, New Cale- donia).

Cerithium zebrum var. attenuata Vignal, 1903:22, pi. 2, fig.

4 (type, MNHNP; type locality. Isle of Pines, New Cale- donia); Dautzenberg & Bouge, 1933:313.

Cerithium zebrum var undulata Dautzenberg ic Bouge, 1933: 316 (Type, MNHNP; type locality, Tuamotus).

Cerithium zebrum var. rosea Vignal, 1903:24, pi. 2, fig. 6 (type, MNHNP; t\pe locality. Isle of Pines, New Caledonia); Dautzenberg & Bouge, 1933:315.

Cerithium zebrum var. cinerea Vignal, 1903:24, pi. 2, fig. 7 (type, MNHNP; type locality. Isle of Pines, New Cale- donia); Dautzenberg & Bouge, 1933:314.

Cerithium zebrum var. nivea Vignal, 1903:24, pi. 2, fig. 8 (type, MNHNP; type locality. Isle of Pines, New Caledonia); Dautzenberg & Bouge, 1933:315.

Cerithium zebrum var. biUneata Vignal, 1903:25, pi. 2, fig. 10

Figs. 1-15. Cerithium zebrum Kiener, showing shell variation and types of synonymous nominal ta.xa. 1-2. Orote Point, Guam, 7.9 mm length; 3. operculum, 1.3 mm length (ISNM 854036); 4. Orote Point, Guam, 7.5 mm length (USNM 854036); 5. Pago Bay, Guam, 7.8 mm length (USNM 774778); 6. Enewetak Atoll, Marshall Islands, 7.9 mm length (USNM 770725); 7. lectotype of Cerithium crossii Deshayes, Reunion (MNHNP), ; 8. Holotype of Cerithium janthinum Gould, Reao, Tuamotus (USNM 5573); 9. SEM of protoconch, bar = 70 ^m; 10. lectotype of Cerithium aspersum Deshayes, Reunion, 8 2 mm (MNHNP); 11-12. Pago Bay, Guam, apertural and right lateral views under SEM, showing sculptural details, 5 8 tnm length (I'SNM 774778); 13. sculpture of early whorls, SEM, bar = 0.9 mm; 14—15. Pago Bav, Guam, dorsal and right lateral views under SEM, 5.8 mm length (USNM 774778).

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THE NAUTILUS, Vol. 107, No. 1

Figs. 18-26. Cerithium boeticum Pease, from Kewalo Basin, Honolulu, Oahu, Hawaii, showing shell variabilit) (USNM 857099). 18-19. Strongly banded morph, 5.8 mm length; 20-21. white morph, 5.7 mm length; 22-23. 5.7 mm length; 24. scanning electron micrograph showing sculptural details and aperture, 4.9 mm length; 25. operculum. 2 mm length; 26. SEM of protoconch and early whorl sculpture, bar = 88 fzm

(type, MNHNP; type locality. Isle of Pines, New Cale- donia); Dautzenberg & Bouge, 1933:314.

Cerithium zelyrum var. triliyieata Vignal, 1903:25, pi. 2, fig. 11 (type, MNHNP; type locality. Isle of Pines, New Cal- edonia); Dautzenberg & Bouge, 1933315.

Cerithium zebrum var. ornata Vignal, 1903:26, pi. 2, fig. 13 (type, MNHNP; type locality. Isle of Pines, New Cale- donia).

Cerithium zebrum var. sticta Vignal, 1903:26, pi. 2, fig. 14 (type, MNHNP; type locality, Isle of Pines, New Cale- donia); Dautzenberg & Bouge, 1933:315.

Cerithium zebrum var mutimaculata Vignal, 1903:26, pi. 2, fig. 15 (type, MNHNP; type locality. Isle of Pines, New Caledonia); Dautzenberg & Bouge, 1933:315.

Cerithium zebrum var. maculata Vignal, 1903:26, pi. 2, fig.

16 (type, MNHNP; type locality. Isle of Pines, New Cal- edonia); Dautzenberg & Bouge, 1933:314.

Cerithium zebrum var. unimacuhita N'ignal, 1903:27, pi. 2 fig.

17 (tspe, MNHNP; type localit\', isle of Pines, New Cal- edonia).

Cerithium zebrum var. aspersa Deshayes. Dautzenberg & Bouge, 1933:314.

Bittium zebrum (Kiener) Cernohorsky, 1972:69-70, pi 14. fig. 10; Salvat & Rives, 1975:272, fig. 74.

Bittium zebrum (Kiener) Kay, 1979:120, figs. 45b-c (not Bit- tium zebrum (Kiener), is Cerithium boeticum Pease 1860).

Description: Shell (Figs. 1-15; Table 1): tiirreted, elon- gate, attaining 10.4 mm length, 3.2 mm width, and com- prising about 9 weakly inflated to flat-sided whorls. Pro-

R. S. Houbrick, 1993

Page 19

Figs. 27-28. Scanning electron micrographs of radula of Cerithium boeticum Pease, Kewalo Basin, Honolulu, Oahu, Hawaii (I'SNM 857099). 27. general view of mid-radular ribbon, bar = 25 ^m; 28. detail of rachidian tooth, bar = 9 nm

toconch (Fig 9) comprising 3 whorls; protoconch 1 nearly smooth, sculptured with suprasutural spiral cord; pro- toconch 2 sculptured with series of subsutural plaits fol- lowed by two strong spiral cords, criss-crossed by minute lirae up to anterior suture. Early whorls (Fig. 13) sculp- tured with 3 beaded spiral cords. Adult whorls sculptured with 4 beaded, major spiral cords each separated from one another by one fine spiral lira. Penultimate whorl with 5 beaded spiral cords, having about 26 spiral beads; beads frequently aligned to form weak a.xial riblets. Body whorl with 11-12 beaded spiral cords and fine spiral lirae. Suture weakly defined. Strong white varices randomly placed on whorls; largest varix on right dorsal side of body whorl. Aperture circular-ovate, a little over one- fourth the shell length. Outer lip thick, relatixely smooth, weakly crenulate at inner edge; columella concave with weak callus. Anterior canal short, but pronounced, ori- ented at 45 degree angle to shell a.xis. Weak siphonal constriction. Anal canal small, defined bv small parietal

plait Shell color white with pink early whorls and adult w horls w ith brown, tan, rose blotches and spiral stripes, bands, or dots. Aperture white. Periostracum thin, light tan.

Animal: Headfoot white, flecked with opaque white, rose or tan. Snout, mantle edge and siphon \ellow . Mantle edge with short yellow papillae. Snout long, extensible, having bilobed tip (lips). Operculum (Fig. 3) tan, cor- neous, ovate, paucispiral with eccentric nucleus. Lateral epipodial skirt and operculiferous lobe absent. Osphra- dium bipectinate, with weakly-defined pectins. Radula (Figs. 16-17) short, about one-ninth the shell length. Rachidian tooth (Fig 17) height equals length, having hourglass-shaped basal plate with spade-shaped basal projection and two small basal lateral butresses; cutting edge with large, pointed central cusp flanked by two small pointed denticles on each side. Lateral tooth with rectangular basal plate having long lateral projection and

Table 1. Shell statistics for Cerithium zcbrum (measurements in mm)

Table 2. Shell statistics for Cerithium boeticum (measure- ments in mm).

Statistic (n = 17)	X	sd	Range	Statistic (n = 17)	X	sd	Range
Length	7.3	1.5	4.2-10.35	Length	6.1	1.8	2.4-10.5
Width	2.4	0.4	1.8-3.2	W^idth	2.3	0.8	1.2-4.6
Aperture length	1.3	0.3	0.8-1.8	Aperture length	1,7	0,7	0.8-2.4
Number of whorls	9.2	1.6	7-13	Number of whorls	8,0	0,9	6-9
Number spiral beads	26,3	6	19-44	Xvunber axial beads	174	1 7	14-20

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THE NAUTILUS, Vol. 107, No. 1

thick central buttress; cutting edge with one weak inner denticle, large spoon-shaped cusp, and three outer den- ticles. Marginal teeth spatulate, curved at tips; inner mar- ginal tooth with three pointed inner denticles, large cen- tral cusp and two outer denticles; outer marginal tooth same but without outer denticles. Esophageal gland pres- ent; stomach large; style sac and crystalline style long, about one-third stomach length.

Synonymic remarks: This species has been the recipient of 23 names, all of which have been based on concho- logical characters and/or differences in shell pigmenta- tion. It is obvious that the authors of these nomina did not employ a modern species concept and failed to rec- ognize the full range of intraspecific variation when pro- posing these ta.xa. Examination of the types of the syn- on\mous nomina re\ealed no significant differences in shell sculpture from that of Cerithium zebrum (Kiener); indeed, the nomina proposed by Vignal (1903) as vari- eties of Cerithium zebrum Kiener were based on mere intraspecific color variation, as Vignal (1903) clearly stat- ed. The holotype of Cerithium janthinum Gould (see Fig. 8) is merely a worn, very wide morph of Cerithium zebrum. Sowerby (1855) introduced the name dilectum in the Thesaurus as a variety of Cerithium zebrum Kie- ner, but the new taxon was indicated only by the itali- cized name in his "Alphabetical list of species", on p. 896. The name dilectum was initially listed on p. 117 as a synonym of Cerithium zebrum, and the legend for the figures of Cerithium zebrum (figs. 107-109) does not include the name dilectum, although one of the figures has an asterix (fig. 207-), which presumably is meant to indicate the varietal taxon, dilectum. Cerithium asper- sum Deshayes is a highly sculptured morph of C. zebrum, as illustrated by the lectotype (Fig. 10). Cerithium crossi Deshayes, 1863, which as shown by the lectotype (Fig. 7), is conspecific with Cerithium zebrum, was incorrectly considered by Crosse (1863) as a homonym of Cerithium crosseanum Tiberi, 1863, a Cerithiopsis species, and was given an unnecessary replacement name, Cerithium maillardi Crosse, 1863. Cerithium boeticum Pease er- roneously has been considered conspecific with Ceri- thium zebrum Kiener by Kay (1979). For a discussion of this issue, see the discussion under Cerithium boeti- cum.

Discussion: Cerithium zebrum is a very common spe- cies, frequently found in the upper intertidal zone among rubble and algae on benches and platforms associated with fringing coral reefs of atolls and islands throughout the Indo-Pacific. In the Hawaiian Islands is also occurs in deeper waters (Kay, pers. com.). It is characterized by an elongate, tapering shell, sculptured with many fine beaded spiral cords and with numerous broad, white, randomly-placed varices. Cerithium zebrum is a colorful species, having a rose-colored apex capped with a dark brown protoconch (see Figs. 1-2,4,6). The adult whorls are frequently white or light pink with tan blotches or with brown and tan bands. While the species varies great- ly in color pattern, shell sculpture is relatively stable

throughout its range. Banded varieties of Cerithium ze- brum may be confused with banded morphs of Ceri- thium boeticum, but the latter species has a more coarse- ly sculptured shell with stronger axial ribs, a more deeply incised suture, and a thick outer apertural lip (see Figs. 18-26). The animal (headfoot), in contrast to the brightly pigmented shell, is a uniform white overlain by opaque white spots, although some shells may also be white.

In contrast to the lecithotrophic development seen in Cerithium boeticum, Cerithium zebrum undergoes a lengthy planktotrophic larval phase and has an elabo- rately sculptured protoconch (Fig. 9) with a deep sinu- sigeral notch indicative of this de\elopmental mode. The operculum of Cerithium zebrum is slightK- more ovate, thicker and opaque, and has fewer spirals than that of Cerithium boeticum.

Cerithium zebrum occurs from Henderson Id., in the Pitcairn Group, throughout French Polynesia and the Hawaiian Islands, and westward throughout the tropical Pacific from Queensland, Australia, north to the Ryu- kyus. It is found throughout the archipelagos of southeast Asia and in suitable localities in the Indian Ocean. In- deed, specimens from Tamarin Bay, Mauritius (AXSP 273492) look very much like those found in Tahiti (Fig. 6) and Guam (Figs. 1-2, 4-5). While Cerithium zebrum has occasionally been collected in assemblages from depths greater than 10 m around the main, volcanic Hawaiian Islands (Kay, in lit.), it is more common on the shallow reefs of the Northwestern Hawaiian Islands at French Frigate Shoals (ANSP 195368, 195384) and Midway (USNM 790897).

To my knowledge, Cerithium zebrum has not been recorded as a fossil.

Cerithium boeticum Pease, 1860

Cerithium pusillum Gould, 1851: 120-121 (holotype, USNM 5572, 4 paratypes, MCZ 216606; type locality, Sandwich Ids [Hawaiian Ids); nol Cerithium pusillum Pfeiffer, 1840, nor Dunker,1859); Gould, 1852:150, pi 10, fig. 172a-b; Gould, 1862:62; Dunker, 1882:108.

Cerithium boeticum Pease, I860: 433 (lectotype [Kay, 1965], BMNH 1962802, 6 x 2.5 mm, 5 paralectotypes, BMNH 1962803; type locality. Sandwich Ids [Hawaiian Ids]); Sow- erby, 1866 "haeticum", pi. 12, fig. 327; 1866b, pi. 16, fig. 114; Trvon, 1887:143, pi. 27, fig. 26; Kobelt, 1898:236, pi. 41, fig. 14; Kay, 1965:48-49, pi. 10, fig. 8.

Biitium pusillum (Gould) Johnson, 1964: 136; Kay, 1979:120 (not Biitium pusillum [Dunker, 1859]).

Bitlium zebrum (Kiener) Kay. 1979: 120. fig. 45b-c (not ze- brum Kiener, 1841, is Bittium pusillum [Gould, 1849]).

Bittium boeticum unilineatum Pse. (sic). Mant, 1923: 121.

Bittium boeticum Pils. & Va. (sic). Mant, 1923: 121.

Description: Shell (Figs. 18-24, 26; Table 2): Shell solid, turreted, reaching 10.5 mm length and 4,6 mm width, comprising about 8 con\ex whorls. Protoconch (Fig. 26) one whorl, smooth with straight lip. Early whorls sculp- tured with two spiral cords and weak axial ribs. Penul- timate whorl sculptured \\ ith 4 major beaded, spiral cords

R. S. Houbrick, 1993

Page 21

each separated from the other with weak spiral Hrae, and each bearing about 17 beads aHned to form 17 strong axial ribs. Bod\ whorl large, sculptured with 9 spiral beaded cords and weak spiral lirae. Several varices ran- domly distributed on shell, strongest opposite outer lip of aperture. Suture deeply impressed. Aperture oval- elongate, a little over one-third the shell length. Anterior canal short, well-defined, oriented at 45 degree angle to shell axis; outer lip thick, strongly denticulate along inner edge; columella concave with moderate callus. Anal ca- nal weak, defined b\ parietal plait.

Animal: Headfoot without lateral epipodial skirt; weak- ly scalloped operculiferous lobe present. Operculum (Fig. 25) corneous, very thin, transparent and paucispiral with slightly eccentric nucleus. Osphradium very large, about one-half w idth of ctenidium, strongK bipectinate with large pectins. H> pobranchial gland well-developed. Me- dial lamina of pallial oviduct with spermatophore bursa and large seminal receptacle. Radula (Figs. 27-28) very short, about one-twelfth the shell length. Rachidian tooth (Fig. 28) wider than tall, hourglass-shaped, with basal plate having short basal projection and two small lateral buttresses; cutting edge with spade-shaped central cusp flanked on each side with three, sometimes two, small pointed denticles. Lateral tooth w ith rectangular basal plate having long lateral projection and short basal but- tress; cutting edge with small inner denticle, long spoon- shaped major cusp, and two, sometimes three, outer pointed denticles. Marginal teeth elongate, spatulate with curved tips; inner marginal tooth w ith two inner denticles long, major central cusp and one outer denticle; outer marginal tooth same but without outer denticle.

Synonymic remarks: Cerithium boeticum has been confused with several other taxa assigned to Cerithium or Bittiiim by authors. The earliest name for the species is Cerithium pusillum Gould, 1851, but as this name is preoccupied, the next available valid name is Cerithium boeticum Pease, 1860. Although the figures subsequently presented by Gould (1852, pi. 10, figs. 172a-b) for Cer- ithium pusillum are not very good, the holotype (USNM 5572) clearK shows that this taxon is different from Cer- ithium zebrum Kiener, with which it has been confused (e.g., Kay, 1979; 120). Cerithium pusillum Dunker, 1859, and Cerithium pusillum Gould, 1851, are different spe- cies, but as both taxa have been referred to Bittium by authors, some confusion has developed about their iden- tity.

Cerithium boeticum Pease is a name seldom men- tioned in the literature and has not been a well-under- stood species. Kay (1965) designated a lectotype and five paralectotypes from the original type lot of six beach- worn specimens, but her illustration of the lectotype (1965, pi. 10, fig. 8) is poor and is not helpful in clarifying the concept of the species. Kay (1979) subsequently placed this taxon into the synonymy of Cerithium zebrum, a species with a wide Indo-Pacific distribution. Further confusion has developed because another Pease (1860) name, Cerithium unilineatum, a valid svnonvm of Cer-

ithium zebrum Kiener, was combined with Cerithium boeticum Pease to form a trinomial In some museum collections the manuscript name, Cerithium gouldianum Pilsbry & Vanatta, is found associated with lots of Cer- ithium boeticum. but the name has no validity.

Discussion: As mentioned above, Cerithium boeticum had been condsidered to be synonymous with the com- mon Indo-Pacific species, Cerithium zebrum Kiener, but the former species has a thicker, less elongate shell with coarser sculpture, few weak varices, a stronger anterior canal, and a different kind of protoconch than Cerithium zebrum (see Figs. 18-26); moreover, Cerithium boeti- cum appears to be restricted to the Hawaiian Islands, whereas Cerithium zebrum is distributed throughout the Indo-Pacific. Shells of the two species frequently share similar color patterns, especially among the banded, striped morphs, but when closely compared, they are seen to be realK' quite different. Radular differences be- tween the tw o species although slight, are consistent and serve to distinguish each of them (see Table 3). The very thin, nearly transparent operculum of Cerithium boe- ticum (Fig. 25) differs from the thicker one of Cerithium zebru m .

Gould (1851) mentioned that Cerithium boeticum (cited as Cerithium pusillum) was "like C. ferrugineum Sa\-, but much smaller". Cerithium ferrugineum is a s\nonym of Cerithium lutosum Menke, a small species from the western Atlantic, and indeed Cerithium boe- ticum does bear some resemblance to small morphs of Cerithium lutosum in overall shell morphology (see Houbrick, 1974, pi. 41).

An unusual anatomical feature of Cerithium boeticum is the large, well-developed bipectinate osphradium. Al- though Cerithium zebrum also has a bipectinate os- phradium, the pectins are poorly defined. A bipectinate osphradium is common to all members of Cerithium Bruguiere and Chjpeomorus Jousseaume (see Houbrick, 1974, 1985), but not as common among Bittium species (pers. obsr). Although Cerithium boeticum has a weakly scalloped operculiferous lobe, the lateral epipodial skirt, indicative of Bittium species, is absent. The absence of a spermatophore bursa in the lateral lamina of the pallial oviduct, which is the hallmark of Bittium species, is one of the chief anatomical reasons for reassignment of this species to Cerithium. However, the specimens studied herein may not have attained complete reproductive ma- turity, and this needs reconfirmation.

Cerithium boeticum lives in shallow water on subtidal rubble where it is frequently found on marine algae. This species has lecithotrophic development, which is reflected in its relatively unsculptured protoconch, com- prising only one whorl with a nearlv straight apertural Up (Fig. 26).

Cerithium boeticum appears to be endemic to the Hawaiian Islands. It is geographically sympatric with Cerithium zebrum, especially in the northern part of the Hawaiian chain. This species has been recorded from the Pleistocene of Molokai (Ostergaard, 1939, as Ceri- thium boeticum).

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THE NAUTILUS, Vol. 107, No. 1

Table 3. Characters defining Ceritbiurn zclmim and Ceri- thiitrn hoeticum.

Cerithium zebruni

Cerilhium hoeticum

Sculpture

1. Weak axial riblets Strong axial ribs

2. Many weak spiral beads Fewer strong spiral beads

3. Weakly impressed suture Strongly impressed suture

4. Many broad white varices Few weak varices

5. Protoconch highly sculji- Protoconch unsculptured tared

6. Thin outer apertural lip Thick outer apertural lip

7. Aperture '74 shell length Aperture 'i shell length

Radula

1. Radula short Radula very short

2. Rachidian height equal to Rachidian wider than tall width

3. Rachidian cusp flanked Rachidian cusp flanked with 2 denticles on each with 3 denticles on each side side

4. Inner marginal with 3 in- Inner marginal with 2 inner ner and 2 outer denticles and one outer denticle

Osphradium

1. Weakly bipectinate Large, strongly bipectinate

Development 1. Plantotrophic Lecithotrophic

A sumniar) ol the dittereiices between these two spe- cies is presented below, in Table 3.

CONCLUSIONS

Evidence is presented above to show that the Hawaiian species, Cerithium hoeticum, is morphologically distinct from Cerithium zebrum. Although both species had pre- viously been assigned to Bittium. anatomical evidence shows that this is incorrect. As both taxa were thought to be Bittium species, they were omitted from my Indo- Pacific Cerithium monograph (Houbrick, 1992). Ceri- thium hoeticum is restricted to the Hawaiian Islands while Cerithium zebrum has a very wide Indo-Pacific distribution, including the Hawaiian Islands.

ACKNOWLEDGEMENTS

I thank Michael Hadfield, of the Univeristy of Hawaii, Honolulu, Hawaii, for the use of laboratory space and for assistance during field studies in Hawaii. I am grateful to Alison Kay for valuable discussions about the geo- graphic distribution of both species throughout the Ha- waiian Islands. Lou Eldredge, University of Guam, kind- ly provided me with lab space and logistic support at the Pago Ray lab of the University of Guam. The work at the marine laboratory at Enewetak Atoll was made pos- sible by a grant from the Atomic Energy Commission. Bernadette Holthuis, University of Guam, kindly ob- served living Bittium zebrum specimens in the field aiul passed on her observations to me. I am grateful for the use the Smithsonian Secretary's Research Opportunity

Fund, w hich covered the costs of transporation and lodg- ing in both Guam and Hawaii during this study. Susanne Braden of the Smithsonian Scanning Electron Micro- scope Lab provided assistance with the SEM micrographs and V'ictor Krantz, Smithsonian Photographic Services, helped with photography.

LITERATURE CITED

Cernohorsky, W. O., 1972. Marine shells of the Pacific, Vol.

2, 411 pp., 68 pis. Pacific Publications, Ltd., Sydney. Crosse, M.H., 1863. Description d'especes nouvelles d'Aus-

tralie. Journal de Conchyliologie 11:84-90, pi. 1. Dautzenberg, P. & J.L. Bouge, 1933. Les mollusques testaces

marins des etablissements Fran9aise de I'oceanie. Journal

de Conchyliologie 27(2);145-469. Deshayes, G.P., 1863. Catalogue des mollusques de I'lle de

la Reunion (Bourbon). 144 pp., pis. Paris, Dentu. Dunker, G. 1859-1860. Neue japanische Mollusken. Mala-

kozoologische Blatter 6:221-240. Dunker, G. 1882. Index Molluscorum Maris Japonica. Nov-

itates Conchologiae, Supplement to Volume 7. Cassell. Gould, A. 1851. Descriptions of new species, brought home

by the US, Exploring Expedition Proceedings of the Bos- ton Society of Natural History 3:118-121. Gould, A. 1852. Mollusca and shells, X'olume 12, 510 pages,

atlas in US. Exploring Expedition during the vears 1838,

1839, 1840, 1841, 1842 under the command of Charles

Wilkes, U. S.N.Boston: Gould & Lincoln. Gould, A. A. 1861. Descriptions of shells collected in the North

Pacific Exploring Expedition under Captains Ringgold and

Rodgers. Proceedings of the Boston Societv of Natural

History 7: 385-389. Gould, A..\. 1862. Otia Conchologica: Descriptions of shells

and mollusks, from 1839 to 1862, 256 pp, Boston, Gould

& Lincoln, Gray, J, E. 1847. A list of the genera of Recent Mollusca,

their synonyma and types. Proceedings of the Zoological

Society of London (for 1847) 15(I78):129-219 (November

1847). Hedley, C. 1899. The Mollusca of Funafuti, Part 1, -Gaster- opoda. Australian Museum, Svdnev, Memoir 3, pp, 397-

488. Houbrick, R.S, 1974, The genus Cerithium in the western

Atlantic. Johnsonia 5(10):33-84, 48 pis. Houbrick, R.S. 1985. Genus Clypeomorus Jousseaume (Cer-

ithiidae: Prosobranchia). Smithsonian Contributions to Zo- ology No,403: iv + 131 pp,, 62 figs, Houbrick, R.S. 1992. Monograph of the genus Cerithium

Bruguiere in the Indo-Pacific (Cerithiidae: Prosobranchia).

Smithsonian Contributions to Zoology No. 510: 208 pp.,

145 figs. Johnson, R. 1964, The Recent Mollusca of .Augustus .\ddison

Gould. Bulletin of the United States National Museum 239:

v -I- 182 pp., 45 pis. Kay, E. A. 1965. Marine mollusks in the Cuming collection,

British Museum (Natural Histor\ ) described by William

Harper Pease. Bulletin of the British Museum (Natural

Histor\ ), ZoologN , Supplement 1, London 96 pp., 14 pis. Kay, E,A, 1979. Hawaiian Marine Shells Bishop Museum

Press, Special Publication 64(4), Honolulu, Hawaii, 653

PP Kiener, L.C. 1841. Species genera! et iconograpliie des co-

R. S. Houbrick, 1993

Page 23

quilles vivantes. Genre Cerite Paris vol 5: 10-4 pp , 32

pis. Kobelt, W. 1888-1898. Die Gattung Ccrithium. in F. H. W.

Martini, & J. H. Chemnitz, Neues systematisches Conchy-

iien-Cabinet ... 1 (pp. 297 pages). Nurnberg: Bauer &

Raspe. Melvill, J.C. & R. Standen. 1895. Notes on a collection of

shells from Lifu and Uvea, Loyalty Islands, formed b\ the

Rev James and Mrs. Hadfield, with a list of species. Journal

of Conchology 8: 84-132, pis. 2-3. Mant, C. F. 1923. Mollusca from the dredging operations at

Kewalo Harbor, Honolulu, 1921. The Nautilus 36(4):120-

123. Ostergaard, J.M. 1939. Reports on fossil Mollusca of Molokai

and Maui. Occasional Papers of Bernice P. Bishop Museum

Honolulu Hawaii 15(6): 67-77. Pease, W. H. 1861, Descriptions of Forty-seven New Species

of Shells, from the Sandwich Islands, in the Collection of

Hugh Cuming, Esq. Proceedings of the Zoological Society

of London 431-438. Pfeiffer, L 1840. Ubersichtder im Januar, Februar und Marz,

1839 auf Cuba gesammelten Mollusken. Archiv Natur- geschite6(l);250-261.

Salvat, B., & C. Rives. 1975. Coquillages de Polynesie. 392 pp, illustrated Papeete, Tahiti.

Schepman, MM. 1909. The Prosobranchia of the Siboga Ex- pedition. Part 2. Taenioglossa and Ptenoglossa. Leyden, Brill, 7 pis.

Sowerby, G.B. 1855 Monograph of the genus Cerithium. .'\danson. In Thesaurus Conch) liorum, or monographs of genera of shells. London, 2(16);847-899, pis. 176-186.

Sowerby, G.B. 1865-66. Monograph of the genus Cerithium Adanson in: Reeve, Conchologia Iconica: or illustrations of molluscous animals. London. 15 (atlas), 20 pis. + index.

Tiberi, N. 1863. Description d'especes nouvelles de la mer Mediterranee. Journal de Conchyliologie 11: 158-160.

Tryon, G.W. 1887. Manual of Conchology; structural and systematic with illustrations of the species (Cerithiidae), First series. Philadelphia, 9: 112-228, 19-39 pis.

Vignal, L. 1903. Sur les varietes du Cerithium zebrum Kiener. Journal de Conchyliologie 51(l):21-27, pi, 2.

THE NAUTILUS 107(1 ):24-28. 1993

Page 24

Rediscovery of TurhineUa thersites Reeve, 1847, with Notes on its Taxonomic Position (Gastropoda: Fasciolariidae)

R. N. Kilburn

Natal Museum

P/Bag 9070

Pietermaritzburg 3200, South Africa

ABSTRACT

The holot\pe of Turbinella thersites Reeve, 1847, was believed to have been collected in China; no further specimens have subsequently been reported. Comparison with recently trawled material indicates that it was actually dredged on the Agulhas Bank. Turbinella thersites is here transferred from the family Turbinellidae to the genus Fasciolaria, within the family Fas- ciolariidae.

Key words: Fasciolariidae; Turbinellidae; South African; ne- ritic; Fasciolaria. Turbinella

INTRODUCTION

Turbinella thersites Reeve, 1847, was based on a single specimen (Fig. 3) originally in the collection of Captain Sir Edward Belcher, and supposedK- from China. Noting that it appeared to be immature, Ree\e obser\ed that "it rather partakes of the character of Fasciolaria", a view echoed b\- Melvill (1891), who speculated that it might belong to either Fasciolaria Lamarck, 1801 (fam- ily Fasciolariidae) or Tudicla Roding, 1798 i^Turbinel- lidae). Kobelt (1874) cited it as Turbinella (Plicatella) thersites, and Tryon (1881) similarly included it within the genus Latirus Montfort, 1810 (= Plicatella S\\ ainson. 1840). FinalK', Yen (1942), in a paper on C^hinese gas- tropods in the Natural Histor\ Museum, London, pub- lished a photograph of the holot\pe, under the name Tudicla thersites, and quoted the type locality without comment. No specimens additional to the holot\pe are on record, and no further reference to the species has been traced, notwithstanding the considerable bod\' of literature that has been published in recent decades on the mollusks of the Sino-japanese region.

,\mong the larger mollusks that are brought up in the nets of commercial trawlers operating on the .Vgulhas Bank, the continental shelf south of South Africa, are several species of Fasciolaria. Most commonly trawled are F. scholvieni Strebel, 1912, bathymorphs of F. lu- gubris lugtdnis Ree\e. 1847, and its eastern sulxspecies F. lugubris heynemanni Dunker, 1871, and the bathyal F. rutila (Watson, 1882); less commonly seen is F. uat- tersac Kilburn. 1974. On rare occasions a fifth species.

distinguishable by its sculpture of auriculate ribs, is trawled. Such ribs similarK' characterize the "lost" Tur- binella thersites, and comparison of juvenile specimens of this "fifth species" with the equally juvenile holotype of T. thersites confirms their identity .

.At the time of description of Turbinella thersites, the only .\gulhas Bank mollusks known had been dredged during the cruises of the H.M.S. Sulphur USo6-1842) and H.M.S. Samarang (1843-1846'. both captained by Belcher. Confusion of localities in Belcher material from these voyages is not infrequent, and using the line of reasoning ad\anced b\ Tomlin (1925: 310). with regard to the origins of the holotvpe of Turrit ella ferruginea Ree\e. 1849, one can speculate that the holotv pe of Tur- binella thersites was originalK amongst the mollusks dredged by Belcher on the .\gulhas Bank during the vo\age of H.M.S. Samarang i^this expedition was spe- cificalK mentioned b\ Ree\e under the description of Turbinella [= Latirus] belcheri Ree\e. 18471 Indeed the case of Turrit ella declivis .\dams & Reeve. 1S50. is directly comparable: although originalK said to have been dredged b\ the Samarang in the "China Sea", this species was subsequentK shown i,Tomlin. 1925: 313) to be characteristic of the Agulhas Bank biota. Although at present little precise data is a\ ailable for Fasciolaria ther- sites. indications are that, like Turritclla dcclivis. it is a continental shelf species endemic to the .\gulhas Bank.

The second known example (Fig. 5) of Fasciolaria thersites was actually collected in 1962. but its identity w ent unrecognized, until it w as .sent to me for comment in 19S(i b\ J. H. McLean of the Los .\ngeles Count) Mviseum. CuriousK . a.ssociated with it w as a similar error in localization. Originating from the collection of the late I'ranz Steiner. the label states: "This shell w as found in dredged santl. Nacala, Mozambique, on the 19 June, 19ti2, b\ nic . BiogeographicalK , it would be unprece- dented for such a temperate-w ater .\gulhas Bank species to live also on the tropical coral coast of northern Mo- zambique, and its origin is sureK ad\ entitious. It is not impossible that this specimen w as jettisoned from a ship docking in Nacala harbor, but although worn, it lacks the porcellaneous appearance normally seen in shells that ha\e lain on coral sand for a length) period. It is thus

R. N. Kilburn. 1993

Pa2e25

Figures 1-2. Protoconch of Fasciolaria thersites Reeve. 18471 Scale lines = 1 mm.

more probable that Steiner accidentalK separated it from a sample of trawled Cape moUusks. and mLxed it with his Mozambican finds. Indeed, in 1962 or 196-3 I was personalK told b\ Steiner then a radio-operator in the merchant navy) that while on the Xacala route he reg- ularK received trawled shelb from a source in Cape Town, who accumulated them in barrels of preserv ative on his behalf.

This species and its temperate-water South .\frican congeners agree in teleoconch characters with the genus Fasciolaria Lamarck. 1799. in its broadest sense. Radula characters, known for all species v Kilbum. 1974. Barnard. 1958). except F. thersites. also agree, .\lthough species with shoulder nodules are generally referred to subgenus ^sometimes even genus) Pleuroploca P. Fischer. 1SS4. such a classification does not address the problem of ta.xa such as Fasciolaria filamentosa \R6ding. 1798) and F. lugubris Reeve. 1S47. in which nodules are present or absent according to individual or population. The fi\e species endemic to South .\frican waters share a close morphological similarity but differ from all other species of Fasciolaria in their extremely large and bulbous pro- toconch (Figs 1-2'. which has a basal diameter of 3.0- 5.0 mm. according to species and individual. Such a protoconch cannot be dismissed as merely an adaptive correlation with mode of development, because this is similarly non-planktotrophic in four of the five other species of Fasciolaria (= Pleuroploca'' in which devel- opment is known [see D'.\saro. 1970a. 1970b. Gohar & Eisawy . 1967. Shepherd & Thomas. 1989). and is there associated with a much smaller protoconch. .\ second character of possible significance is egg-capsule shape: in the sole Cape species in which these are known {F. lugubris\ capsules differ from those reported for other species of Fasciolaria in being dorsally rounded without a demarcated escape hatch ^see Kilburn & Rippey. 1982: text fig 62 i. Egg capsules have been described for three species from North .\merica. and one each from the

tropical Indo-Pacific, Mediterranean and southern -\us- traha ; references given above, also BaccL 1947). In all of thec-e. the capsule is flat-topped, with a structural es- cape hatch dorsally. It is possible that recognition of the South -\f rican species-complex at the subgenxis level may ultimately prove warranted on grounds of protoconch size and perhaps capsxile form.

Fasciolaria thersites Figures 1-7

Reeve. 1S47 , n. comb.

Turbinella thersites Reeve. 1S47: pi. 4. sp 21: MeKiU. 1S91: 409. Type localit> : China [here emended to .\gulfaas Bank].

Turbinella , Flicatella '• thersites: Kobelt in Kster & KobelL 1574: 71. 157. pL 18. fig. 1 ^afte^ Reeve': Kobelt 1S76: 21.

Lc-'":' -rf-rfites: Tryon. 1851: 91. pL 6S. fig. 137 .after Reeve).

7 '-'^tes: Yen. 1942; 237, pL 25. fig. 17S iholot>-pei.

r ^>--- .i^'-.i^ icattersae ynon Kjlbum. 1974 : Richards. 1981: 63, pi. :35. fig. .300.

Description: Shell fusiform, with bluntly papiUiform apes, slphonal canal equal in length to aperture, curved slighdv to right: suture moderately shallow, whorls strongly convex, except immediately below suture where they are shaUowly concave. Inner fip with a thin callus glaze, smooth except for a thin spiral ridge just above mid-parietal region and three obhque basal pleats; of these the strongest pleat is situated at entrance to siphonal canal and the weaker posterior two decrease in strength and are scarcely visible from without the aperture. Te- leoconch sculptvtred by strongly prosochne. rather turn id axial ribs, which project at shoulder in a roundedly au- riculate manner: in most examples, asials become weak on later whorls, except sometimes for an occasional strong rib, but they may remain strong throughout: fine spiral threads, crossed by microscopic coUabral threads, present overall. First teleoconch whorl with 8 straight prosocline asials. the first few low and relatively close, thereafter in transverse section thick, strongly rounded, slightly

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THE NAUTILUS, Vol. 107, No. 1

R. N. Kilburn, 1993

Page 27

compressed, more or less equal to intervals, which are flattened; Second whorl with 6-7 axials, third generally with 5, fourth with 4. Spiral lirae unequal in width, groups of fine threads being often separated by groups of coarser ones, those on siphonal rostrum rather uniform in strength. Collabral threads ma\ be pliculate in places, generally rendering intervals between spiral lirae punc- ticulate and the spirals themselves somewhat scabrous. Off white, with a thin yellowish-brown periostracum. Protoconch bulbous, of about IV2 whorls, first whorl strongl) tilted, smooth, last half whorl with uneven, pro- socline axial riblets; maximum breadth 3.0-4.8 mm, height 3.1-4.4 mm (ratio breadth/height 0.87-1.13). Maximum dimensions 102.0 x 39.6 mm (R. Le Maitre collection). Holotype (juvenile) 49.0 x 22.1 mm. Oper- culum oblanceolate with rather obtuse apex, moderately thick with coarse growth lines; color amber-brown, with darker outer edge.

Distribution: Agulhas Bank,

Type material: Holotype in the Natural History Muse- um, London, accession number 1879.2.26.116, from Lombe-Taylor collection.

Other material examined: Agulhas Bank [Natal Museum (NM) D3482: R. Le Maitre, also several specimens in colln Le Maitre]; off Cape St. Blaize area, ex pisce (NM B1087; R. Le Maitre, juvenile); off Storms River mouth, 69 fathoms [= 126 m], in mud, a juvenile shell (NM S4953: C. Marais); same data, 64 fathoms [= 117 m], a broken juvenile (NM S5646; C. Marais); "Nacala harbor, dredged sand", empty shell (NM K1526: F. Steiner, don. J. H. McLean).

Remarks: I have seen no adults of this species with an undamaged lip, and only two specimens (both dead ju- veniles of about 3 teleoconch whorls) bear a precise lo- cality. Its exact distribution on the Agulhas Bank, both geographic and bathymetric, consequently remains to be established.

Fasciolaria thersites shows much variation in size of protoconch and extent of axial ribbing on the teleoconch; too little material is available to judge whether this re- flects geographic, individual or bathymetric variation. The smallest protoconchs measured occur in the holotype and in the specimen purportedK' from Nacala (although it is more or less worn in both examples); in the latter individual the axial ribs are unusually strong on later whorls. Similar variability in protoconch size was re- ported for F. schotvieni Strebel, 1912, by Kilburn (1974). In appearance F. thersites is most similar to F. wattersae Kilburn, 1974, an uncommon species which inhabits the Mossel Bay-Algoa Bay area at depths of about 100-120

m. In F. wattersae (Fig. 7) the axial ribs are never au- riculate, the spiral sculpture is markedly coarser, and pliculate axial striae are totally absent. Although appar- ently inhabiting similar depths, F. thersites is a much thinner-shelled species. Among the species of Fasciolaria endemic to South Africa, the operculum in F. thersites is unique in its amber-brown color, this being dark brown in the other species.

ACKNOWLEDGMENTS

I wish to thank Ms. Kathie Way of the Natural History Museum, London, for the loan of the holotype of Tiir- binella thersites. Messrs. R. Le Maitre and C. Marais for providing material from the Agulhas Bank, and Dr. J. H. McLean for donating the Steiner specimen to the Natal Museum. Drs. D. G. Herbert and B. R. Stuckenberg read the manuscript, and Mrs. Linda Davis prepared the line drawing.

LITERATURE CITED

Bacci, G. 1947. Le capsule ovigere di Cohimbella rustica (L.) e di Fasciolaria lignaria (L.). Bolletino Zoologico 14; 75- 81.

Barnard, K. H. 1958. Contribution to the knowledge of South African marine Mollusca. Part I. Gastropoda: Prosobran- chiata: Toxoglossa. ,'\nnals of the South African Museum 44(4):73-163, figs. 1-30, pi. 1.

D'Asaro, C. N. 1970a. Egg capsules of some prosobranchs from the Pacific coast of Panama. Veliger 13:37-43,

D'Asaro, C. N, 1970b, Egg capsules of prosobranch mollusks from South Florida and the Bahamas and notes on spawn- ing in the laboratory. Bulletin of Marine Science. 20:414- 440.

Gohar, H. A. F. & A. M Eisawy. 1967. The egg masses and development of five rachiglossan prosobranchs from the Bed Sea Publications of the Marine Biological Station of Ghardaqa. 14:215-268.

Kilburn, R. N. 1974, Taxonomic notes on South African ma- rine Mollusca (3): Gastropoda, Prosobranchia, with de- scriptions of new taxa of Naticidae, Fasciolariidae, Ma- gilidae, \'olutomitridae and Turridae, Annals of the Natal Museum 22(1): 187-220,

Kilburn, R.N. & E. Rippey, 1982. Sea Shells of Southern Africa. Johannesburg: Macmillan.

Kobelt, W. 1844-1876. Turbinella und Fasciolaria. In Kster, H. C. & Kobelt, W., Systematisches Conchylien-Cabinet von Martini und Chemnitz, 2nd Edition, 3(3a):l-164, pis, 1-32,

Melvill, J, C, 1891. An historical account of the genus La^irus (Montfort) and its dependencies, with descriptions of elev- en new species, and a catalogue of Latirus and Peristernia. Memoirs and Proceedings of the Manchester Literar\ and Philosophic Society [4] 4:365-411.

Figures 3-7. Fasciolaria thersites (Reeve, 1847) and F. wattersae Kilburn, 1974 Fasciolaria thersites: 3. Juvenile holotype of Turbinella thersites Reeve, 1847, Natural History Museum, London, 1879 2.26.116, 49.0 x 22 1 mm. 4. Immature example from Agulhas Bank, 78.9 x33,6 mm, in R, Le Maitre colln, 5, Specimen supposedly from Nacala Bay, NM K1526, length 76,2 mm. 6. Adult example, Agulhas Bank, depth unknown, NM D3482, length 100,2 mm, outer lip damaged. 7. Fasciolaria wattersae Kilburn, 1974, S. E. of Mossel Bay, 119 m, NM E5898, 98.7 x32.3 mm.

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Reeve, L. A. 1847. Monograph of the genus Turbinella. Con- chologia Iconica -1. London: Reeve

Richards, D. 1981. South African Shells. A collector's guide. Cape Town: Struik,

Shepherd, S. A. & I. M. Thomas. 1989. Marine Invertebrates of southern Australia. Part II. .Adelaide: S. Australian Gov- ernment Printing Division.

Tomlin, J. R Le B. 1925. Reports on the marine Mollusca in

the collections of the South African Museum. I. Turritel- lidae. .Annals of the South .\frican Museum 25:309-316.

Tryon, G. W. 1881. Tritonidae, Fusidae, Buccinidae. In: Manual of Conchology 3. Philadelphia, privately pub- lished.

Yen, T. C. 1942. A review of Chinese gastropods in the British Museum. Proceedings of the Malacological Society of Lon- don. 24:170-289, pis. 11-28.

THE NAUTILUS 107(1 ):29-32. 1993

Page 29

The Rediscovery, Morphology, and Identity of Conus emersoni Hanna, 1963

John K. Tucker

llliiKiis Natural Histur\ Survey

LTRMP

P.O. Bo.\ 36S

West Alton, MO 63386, USA

James H. McLean

Natural History of

Los Angeles County 900 E.xposition Boulevard Los Angeles, CA 90007, USA

ABSTRACT

Conus emersoni is reported from 310 ni off Isla Sanla Maria (Floreana), Galapagos Islands, the first record subsequent to its original description. The species is redescribed from eight ad- ditional specimens; its operculum, raduia, and periostracum are described for the first time. Affinity of the species to C. teramachii Kuroda, 1956, is discussed.

Key words: Conidae, Contis emersoni. Galapagos Islands, rad- uia.

INTRODUCTION

Subsequent to its description 29 years ago (Hanna, 1963) from two dead, faded and poorly preserved specimens, Conus emersoni has remained an enigmatic member of an otherwise extensively studied genus in the Eastern Pacific region. Even as he proposed the species, Hanna (1963) suggested that it might be conspecific with the Indo-West Pacific species C. australis Holten, 1802, whereas Walls (1979) placed it as a possible synonym of another Indo-West Pacific species, C. orbigniji Audouin, 1831. Keen (1971) treated the species as valid but made no comments on its relationships. Finally. Coomans et al. (1986) considered it to be a tentatively valid species but noted that it could be based on fossil material.

Here we report upon eight recently collected speci- mens from moderately deep water at the Galapagos Is- lands, two of which are in the collections of the Natural History Museum of Los Angeles County and six in the American Museum of Natural History. All were provided by Andre and Jacqueline DeRoy, residents of the Ga- lapagos Islands. These specimens extend the distribution from Cabo San Lucas, Baja California Sur, to the Ga- lapagos Islands, Ecuador, and allow a redescription of the species with the first report on the morphology of the radular tooth, the operculum, and the periostracum.

Abbreviations of museums mentioned in the text: AMNH, American Museum of Natural History, New York; CAS, California Academy of Sciences, San Fran- cisco; LACM, Natural History Museum of Los Angeles County.

SYSTEMATICS

Conus emersoni Hanna, 1963 (figures 1-13)

Contis emersoni Hanna, 1963;25, pi. 1, fig. 2; Walls, 1979:776 [with unnumbered figure of CAS paratypej; Coomans, Moolenbeek & Wils, 1986:11-4, fig. 718 [holotype, 2 views].

Conus (Asprella) emersoni. Keen, 1971:663. fig. 1497 [holo- type].

Diagnosis: Spire scalariform throughout its length, shoulder angle retaining square nodules; sculpture on final whorl of numerous, closely spaced, shallow sulci; posterior notch shallow; whorl tops sculptured by one to two cords that fade in whorl three to be replaced by numerous fine striae.

Description: Shell elongate-conical, whorl sides flat to very slightly convex; shoulder angular. Anterior end not deflected dorsally. Sculpture of numerous (30-50) closely spaced, shallow sulci, most pronounced at anterior end and fading in intensity towards shoulder. Color pattern variable, consisting of three irregularly developed bands, at shoulder, in area just posterior to midbody area, and in area just anterior to midbody. Bands variously inter- rupted and scalloped, producing reticulate or blotched pattern; bands separated by areas with rows of spiral dashes or longitudinal reticulations. Dashes and reticu- lations may be quite pronounced (holotype) or lacking (Galapagan specimens). Anterior end marked by spirally elongated blotches or lines. Color markings in fresh spec- imens medium brown, fading to light brown in dead specimens.

Spire very slightly convex in profile, scalariform throughout and moderately elevated, carinate, carina interrupted by numerous square nodules, 30-40 per whorl; nodules fading in whorl six although carina may remain pronounced. Protoconch unknown (not intact in any of the specimens). One or two spiral cords on first two or three teleoconch whorls, replaced on later whorls by numerous, exceedingly fine striae. Whorl tops colored by variably developed markings, matching those of body whorl, between nodules or crossing entire width of whorl

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THE NAUTILUS, Vol, 107, No. 1

Figure§ 1-7. Conus emcrsurii Hanna, 1963 Figures 1-3. Type material dredged off Los Fraiies, Baja California, depth 549 111 L Holotype, AMNH 1052n, length 43 0 mm, faded, dead-collected specimen, lacking periostracum. 2, 3. Paratype, CAS 12405, length 49.0 mm, subfossil specimen (surface gray), showing naticid bore hole. Figures 4-7. Newly reported specimens dredged off Isla Santa Maria (Floreana), Galapagos Islands, Ecuador, depth 310 m. 4. AMNH 248261, length 46.2 mm, dead- collected specimen. 5. LACM 146906a, length 33.3 mm, live-collected specimen with periostracum intact. This specimen was used for opercular and radular illustration. 6. 7. LAC;M 146906b, length 34 0 mm, dead-collected specimen with periostracum removed to show color pattern.

top. Whorl tops slightly but distinctly concave in cross section. Posterior notch shallow and C-shaped.

Aperture narrow, white inside e.xcept where exterior coloration shows through near lip. Interior constrictions and aperturai flanges absent or at least not developed in available specimens.

Periostracum thick, dark brown, markedly pilose both on body and spire. Extremely Bne hairlike extensions of periostracum not organized into any obvious pattern. These projections are apparently easily worn off, as they are pronounced on the dorsal side of one live-collected specimen (figure 5) but are not obvious on the ventral side of the same specimen.

Dimensions (.see table I): The known specimens range in length from 23.0 mm to the 49.0 mm length of the paratype (figures 2, 3). The ratio of width to length ranges from 0.43 to 0.50 (table 1 ). The largest Galapagan spec- imen (figure 4) is 46.2 mm in length. All specimens have the protoconch eroded, the spire tips filled by secondary shell deposition.

Operculuni illustrated in figure 8 is 27% of aperturai length, weakly serrate on outer edge.

Kadular tooth (figures 9-13) small, 285 jum in lengtli; massive base with pronounced basal spur; waist located on anterior half of tooth, with small spine on posterior

border in same plane as basal spur. Tooth opening rather long, extending about one-cjuarter the length. Tip w ith small barb opposite short blade.

Distribution: The holotype and one paratype were col- lected oft Los Fraiies, Cape San Lucas, Baja California in 550 m (given originally as 300 fathoms by Hanna, 1963). The eight newly discovered specimens were dredged in 310 m (170 fathoms) off Isla Santa Maria (Floreana), Galapagos Islands, 7 May 1979 by Andre and Jacqueline DeRoy (table 1).

DISCUSSION

The rediscovery of Conus emersoni in the CJalapagos Islands should put to rest speculation that this species is a synonym of either Conus australis (suggested by Han- na, 1963) or C. orbignyi (suggested by Walls, 1979). Each of these Indo-Pacific species is unlike C. emersoni in having persistent sulci on the body whorl along with persistent cords on the spire \\ horl tops. C'onus emersoni differs in having the sulci strong only anteriorly and in having fine spiral striae on the whorl tops. Radular dif- ferences are that the radular tooth of C. orbignyi has three anterior barbs (Kilburii, 1973: fig 6), whereas that

J. K. Tucker and J. H. McLean, 1993

Page 31

.-H*

W^

»

m0

10

11

Figures 8-13. Conus emcrsoni Hanna, 1963 8. Operculum, same specimen as figure 5, length 7 3 mm, nucleus lost. Figures 9-13. SEM views of single radular toolli, length 285 m'". from same specimen as in figure .5. SEM photos by H. Chaney 9. Oblique anterior view showing apical surface, with pronounced basal spur and small spine on posterior border of waist. 10. Enlarged view of apical surface, with small barb and enrolled blade. 11-13. Three lateral views, showing differing axial rotation of tooth

of C. emersoni has but two. The radular tooth of C. australis has a serrate shaft along with an enlarged cusp at the posterior end of the row of serrations (A. J. Kohn, radular slide collection); neither feature is present on the radular tooth of C. emersoni.

The scalariform spire and color markings of Conus emersoni have a superficial resemblance to that of the Panamic species C. emarginatus Reeve, 1844 (a species often misidentified as C. recurvus Broderip, 1833). Dif- ferences are that C. emarginatus has a deep posterior notch (rather than shallow notch) and a smooth (rather than pilose) periostracum. The radula of C. emarginatus (Nybakken, 1970; fig. 5, as Conus recurvus) has three barbs anteriorly, like that of C. orbignyi, rather than C. emersoni, in which there are two barbs.

The scarcity of C. emersoni may be due to the great depth at which it occurs and the paucity of sampling at depths below 300 m.

It is possible that the specimens from the Galapagos Islands are specifically or subspecifically distinct. They differ in color pattern (that of the holotype being more intricate) and in spire profile (that of the holotype ap- pearing to be more acute). However, such intraspecific differences in color pattern are not uncommon in Conus. In fact, the faintly indicated color pattern of the paratype that shows on the better preserved dorsal surface (figure 3) is more similar to that of the Galapagan specimens (figures 5-7) than to that of the holotype (figure 1). The ground color of the paratype has a gray cast that is suggestive of fossil or subfossil condition. The holotype is in fresher condition, although it retains no periostra-

cum; it shows evidence of growth damage to the shoulder at a stage two whorls above the termination of the lip, which appears to have altered the profile of the final two whorls, resulting in a greater downward slope to the spire and the loss of the nodules in the final two whorls.

The question as to whether the two widely disjunct records represent the same species can only be answered after additional specimens from the vicinity of the type locality become known. It is our opinion, based on the specimens examined, that there is no clear evidence to suggest that the Galapagan specimens are not conspecific with the Mexican specimens.

Conus emersoni is not closely similar to any other eastern Pacific conid. Shell morphology, including the

Table 1 . Shell dimensions and proportions of the known spec- imens of Conus emersoni Hanna, 1963.

				Width/
Specimen	C:ondition	Length	Width	length
AMNH 92200 (holotvpe	dead	43.0	18.5	0.43
CAS 1240.5 (paratype)	subfossil	49.0	22.5	0.46
LACM l-)6906a	live	33.9	17.0	0.50
LAC:M 146906b	dead	340	15.5	0.46
AMNH 248262	live	35.0	15.7	0.45
AMNH 248263	live	31.5	14.3	0 45
AMNH 248261	dead	46.2	22.3	0.48
AMNH 248169a	live	23.0	10.8	0.47
AMNH 248169b	dead	30.0	149	0.50
AMNH 248169c	live	26 8	12 8	0.48

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THE NAUTILUS, Vol. 107, No. 1

14

15

Figures 14, 15. Conus teramachii Kuroda, 1956 14. Speci- men with growth scar producing lowered shoulder angle of final whorl, periostracum removed. Off NE coast Taiwan, trawled, depth unknown. LACM 68994, length 79 8 mm. 15. Operculum with strongly serrate edge, nucleus lost, trawled off Taiwan. Specimen in H. Chaney collection, length 19.1 mm.

shoulder carina with square nodules, is similar to that of C. teramachii Kuroda, 1956 (figure 14), a species re- ported from similar depths off Japan and Taiwan (Ku- roda, 1956; Walls, 1979). Our illustrations of the radular tooth of C. emersoni (figures 9-13) are comparable to those of Azuma (1961: fig. 11) for C. teramachii (as C. petricosus Azuma, 1961). In addition, C. teramachii also has a strongly serrate operculum (figure 15), much more pronounced than that of C. emersoni (figure 8). The character state of the serrate operculum was stressed in the original diagnosis of the subgenus Profundiconus Kuroda, 1956 — type species Chehjconus {Profundico- nus) profundorum Kuroda, 1956 [= Conus smirna Bartsch and Rehder, 1943]. The type species of Profun- diconus also has square nodules on the shoulder carina, but these are apparent only in young stages.

We refrain, however, from further treatment of the subgeneric allocation of the species under discussion be-

cause comparison to other available generic level taxa is beyond the scope of this paper. We recognize that a generic level classification of Conidae needs to be based on all the recognized species, including fossils, at a min- imum treating characters that include adult and juvenile shell morphology, and, for the living species, the oper- culum, and radula.

ACKNOWLEDGMENTS

We thank Alan J. Kohn of the L'niversity of Washington for allowing one of us (JKT) to study his radular slide of C. australis. William K. Emerson and Walter E. Sage of the American Museum of Natural History made the ho- lotype and other specimens of C. emersoni available for study. Terrence M. Gosliner of the California Academy of Sciences arranged for loan of the paratype specimen. We thank Henry W. Chaney of the Santa Barbara Mu- seum of Natural History for the SEM photos of the rad- ular tooth of C. emersoni and the photograph of the operculum of C. teramachii. We are grateful to Henry W, Chaney, William K. Emerson, Alan J. Kohn and Walter E. Sage and two anonymous referees for reading the manuscript and offering helpful suggestions. Finally, and most importantly, we thank Jacqueline and Andre DeRoy for providing the specimens of C. emersoni that form the basis for this paper.

LITERATURE CITED

Azuma, M. 1961. Descriptions of six new species of Japanese marine Gastropoda. Venus 21(3):296-303.

Coomans, H E., R. G. Moolenbeek, and E. Wils. 1986. Al- phabetical revision of the (sub)species in recent Conidae. 9. ehraeus to extraordinaritis with the description of Conus elegans remalhoi. nov. subspecies. Basteria50;93-1.59, figs. 667-760.

Hanna, G. D. 1963. West American mollusks ot the genus Conus — II. California Academy of Sciences, Occasional Papers, no. 35, 103 p., 11 pis.

Keen, A. M. 1971. Sea shells of tropical West America, second edition. Stanford University Press, Stanford, C.-^, 1064 p.

Kilburn, R. N. 1973 Notes on some benthic Mollusca from Natal and Mozambique with descriptions of new species and subspecies of Calliostoma, SolarieUa. Latiaxis. Bab- ylonia, Fusinus. Bathytoma and Conus. Annals of the Natal Museum 2I(3):557-578, figs. 1-17.

Kuroda, T. 1956. New species of the Conidae (Gastropoda) from Japan. Venus 19(1): 1-13, 1 pi.

Nybakken, J. 1970. Radular anatomy and systematics of the West .'\merican Conidae (Mollusca, Gastropoda). Ameri- can Museum Novitates 2414:1-29, figs. 1-45.

Walls, J. G. 1979. Cone shells, a synopsis of the living Conidae. T. F. H. Publications, Inc., Neptune City, NJ, 1011 p.

THE NAUTILUS 107(l):33-42, 1993

Page 33

The Benthic Mollusk Faunas of Two Contrasting Reef Paleosubenvironments: Falmouth Formation (late Pleistocene, Last Interglacial), Jamaica

Stephen K. Donovan

Department iil Ch'iiIoi;\ University of the West Indies Mona, Kingston 7 JAMAICA

D.T.J. Littlewood'

Haskin Shellfish Heseareh Laboratory

Institute of Marine and Coastal

Sciences

Cook College/ NJ A ES

P.O. Box B-8

Port Norris, New Jersey 0S349 l!SA

ABSTRACT

The last interglacial (about 125,000 years old) raised reefs of the Falmouth Formation of Jamaica contain a diverse fauna of benthic mollusks. Large collections of mollusks ha\e been made from two contrasting reef localities and paleosubenvi- ronments. Calcareous muds of lagoonal origin were well-ce- mented, biassing collecting tow ards larger individuals, whereas poorlv-cemented santly sediments of a coral framework were friable and thus amenable to bulk sampling, yielding numerous micromoUusks. Identification of over 3,000 bivalve, gastropod and scaphopod specimens shows the molluscan faunas of each environment to be dominated by different species. The coral framework fauna is numerically dominated b\ the microgas- tropod Caecitm piilchcllinu Stimpson, 1851, other epifaunal gastropods and arks, while Bulla .striata Bruguiere, 1792 and ceriths dominate the lagoonal sediments. Only Cerithium al- gicola C.B. ,^dams, 1848, forms more than 2"; of the fauna at both localities. 17% of the extant species (27% of the common species) of shallow water benthic mollusks (excluding chitons) from Jamaica have been identified from these two localities.

Key words Late Pleistocene; benthic reef mollusks; Jamaica.

INTRODUCTION

The present paper is a preliminary report of the mol- luscan faunas from the late Pleistocene (the last inter- glacial or Sangamonian) Falmouth Formation (125,000 years B.P.) of northern Jamaica. The mollusks of the Falmouth Formation are important for two principal reasons. Firstly, the Neogene and Quaternary fossilif- erous deposits of Jamaica contain a diverse fauna of benthic mollusks that have hitherto been largely ignored

' Current address; Department of Palaeontology, British Mu- seum (Natural Historv), Cromwell Road, London. S\V7 5BD, ENGLAND

by systematists. Indeed, only the famous Pliocene Bow- den shell bed in southeastern Jamaica (Woodring, 1925, 1928) and the fauna of the Early Pleistocene Manchi- oneal Formation (Trechmann, 1930) have so far received monographic treatment. This lack of published infor- mation does not reflect the true diversity of the mollusk faunas through this interval and ma\ thus prove mis- leading to workers not familiar with the geology of the island. For example, Petuch (1988:49) considered that there are few exposures of Miocene age preserved within the Caribbean and South American region, and did not include Jamaica in his list of productive sites, yet in a preliminary survey Jung (1972) listed members of 19 genera from the extensive deposits of the Newport For- mation (Lower and Middle Miocene) of the island.

Further, molluscan faunas from last interglacial reefs (and other Pleistocene marine environments; Valentine, 1989) can be a valuable adjunct to studies of extant as- semblages from the shallow benthos (but see cautionary comments in Johnson, 1960). The Pleistocene raised reefs of the Caribbean region are recognised to include large faunas of fossil mollusks (see, for example, Cerridwen & Jones, 1991). Unlike those of certain other areas (such as Aldabra Atoll; Taylor, 1978), Caribbean mollusk fau- nas have apparently changed little since the last inter- glacial (Petuch, 1988:119), an observation that may have important implications for the study of faunal associa- tions in Recent reefs and associated environments. Mol- lusk faunas in various biofacies w ithin Pleistocene raised reefs are generalK easy to sample, outcropping adjacent to the coast on many Caribbean islands, thus permitting large collections to be made for systematic and paleo- ecological analysis.

Geology and geological nomenclalure: The Falmouth Formation in the Discovery Bay-Rio Bueno Harbour re- gion of Jamaica's northern coast (figures 1-3) rests un- conformably on the dolomitized Plio-Pleistocene reef (Land, 1991) of the Hopegate Fonnation. Lithofacies

Page 34

THE NAUTILUS. Vol. 107, No. 1

2 1^	^	^	0	km 1	' ^-—
^^=^^8=-	^^2	\
		^ ^	1^ ^^	% ■^1	DB Jy
^"¥1	i	,54-70		^)	Ftl

W/!?\ TerrigencHJS grainstcxie facies Mi::::iij Mdluscan algal gralnstone facies pt'«';1 Mdkjscan biomlcritic wackestone fades f n Biomicritic packstone facies I I Coralline boundstone facies Hopegate Formation

Figures 1-3. Maps ol slud) arta;. 1 Outline map uf JamaiLa, showing the location of the Discovery Bay (DB) region with respect to Kingston (K), Montego Bay (MB) and Ocho Rios (OR) 2 Topographic map of the Discovery Bay-Rio Bueno Harbour (RBH) area, showing the positions of localities 1 and 2. Contours in m. 3 Geological map of the Discover) Bay-Rio Bueno Harbour area (redrawn after Larson. 19So: figure 6). showing the relative distributions of the major sedimentary facies of the Falmouth Formation in relation to the underK ing Hopegate Formation (key right).

within the Falmouth Formation reef (Larson. 1983) con- tain associated distinct faunal assemblages which have been recognised from the evidence of corals (Larson. 1983: Liddell et ai. 1984) and echinoids (Gordon & Donovan. 1992).

History of research: Hill (1899) named the Falmouth Formation, and recognized the essential elements of the mollusk fauna to comprise Lucina, Cardium. Area. So- len and Bulla. Hill (1899. 155) considered this fauna to be worthv- of careful stud\ b\ paleontologists, an invi- tation that has not been taken up in over 90 \ ears. Rob- inson (1958) noted Area spp. from the elevated reef at east Rio Bueno Harbour (localitv 1 herein), and Chione cancellata (Linnaeus. 1767) and Bulla cf. striata Bru- guiere. 1792. from the lagoonal facies east and west of Falmouth. Parish of Trelawny (probabh lithologicalK- similar to locality 2 herein). In 1960. Robinson considered the Falmouth Formation in the Parish of St. .Ann to include the moUusks Lueina. Codakia. Chione and Bul- la, and later commented that this rich fauna is identical with the living fauna of the Jamaican coastal waters (Robinson. 19&3:52). Recent studies of the fossil scapho- pods of Jamaica (Donovan and Littlewood. 1989; Don- ovan, 1990) ha\e recognised Dentalium sp. cf. D. (An- atalis) antillarum d'Orbigny, 1842, and D. (Graptacme) semistriolatum Guilding. 18;34. from the east Rio Bueno Harbour locality.

The specimens discussed herein are deposited in the Department of Palaeontology, British Museum (Natural History). For uncertainties in our taxonomic assignments (particularly for poorly preserved or fragmentary spec-

imens), we have used question marks thus: Agenus ?spe- cies signifies that we are uncertain of the specific assig- nation: ? Agenus aspeeies indicates that some doubt exists concerning the generic land. thus, also specific! assign- ment. This differs in detail, but not in spirit, from the recommendations of Bengston (1988).

MATERIALS AND METHODS

The Falmouth Formation of the Discovery Bay-Rio Bueno Harbour area has been subdivided into five principal reef al subenv ironments by Larson (1983; figure 3 herein). Large collections of benthic mollusks were made from two contrasting paleosubenvironments ^localities 1 and 2, described below) within this continuum. These par- ticular subenvironments and localities were chosen be- cause of their large mollusk faunas and easy access. The mollusk collections from each locality were made over a period of 22 months, from .April 19SS imtil February 1990. Both collections are time-averaged, having been collected from float, the rock face and as bulk samples from throughout 2-4 m of section in each case, as bedding planes and other obvious time marker horizons are not apparent. Howev er. the \ alue of collecting mollusks from discrete beds (e\ en when preserved) within reefs is de- batable, as at an\ one time the fauna w ill include shallow and deep infaunal. sediment surface epifaunal. and (in the case of the three-dimensional coral framework at localitv 1) epifaunal taxa living well above the soft sed- iment surface.

Specimens collected in the field were generally at least

S. K. Donovan and D. T. J. Littlewood, 1993

Page 35

.y .■^.

J'-^

■->^ ^ , x#

^ ^:.'^'

-<; :^<'

^-ii-rv-^is*; '

m a.

Figures 4-7. Field photographs of molhisks of the Falmouth Formation 4-. Stromhus gigas Linnaeus, 1758, at locahty 1; 0.3 x. 5-7. LocalitN' 2, 5, MainK Bulla striata Bruguiere, 1792; 0 6 x. 6. General view of weathered surface showing abundant (mainly molluscan) shell hash; 0.6 x 7. MainK Bulla striata Bruguiere, 1792, associated with an articulated shell (arrowed) of Chione paphia (Linnaeus, 1767); 0.4 x.

5 mm in maximum dimension and even shells of this size were easily overlooked without repeated scanning of a limited area at a time. It proved much easier to detect small specimens during laboratory analysis using a Wild binocular microscope. Preliminary field identi- fications were checked in the laboratory using standard taxonomic references, including Abbott (1954, 1958, 1974), de Jong and Coomans (1988), Fisher (1988), Hum- frey (1975), Morris (1987), Vaught (1989), and Warmke and Abbott (1961). Total numbers of whole shells and (for bivaUes) disarticulated valves are tabulated \\'hole shell equivalents (discussed in Cerridwen and Jones, 1991 ) were used in calculating relative proportions of moUusks for graphical analysis.

Locality 1

(Locality 7 of Liddell et a/., 1984; locality 3 of Donovan

6 Gordon, 1989). East side of Rio Bueno Harbour, Parish of St. Ann, with the Falmouth Formation exposed as a line of low cliffs (GR 394 572). At this locality the un- conformable contact with the underlying, dolomitised Hope Gate Formation (figure 3) formed the hard sub- strate for Falmouth Formation reef growth. Previous interpretations have considered this locality to represent either a patch reef in the back reef lagoon within the molluscan biomicritic wackestone facies sensii lato (Lar- son, 1983; figure 3 herein) or perhaps part of the shallow- fore reef (Robinson, 1958; Liddell et a!., 1984).

Mollusk-rich sediments at this locality occur beneath an altered caliche cap (Land & Epstein, 1970) in a frame- work of shallow-water corals, particularly Porites spp. and Acropora spp. (Liddell et al., 1984: 77). The matrix between corals is a friable, weakly-cemented carbonate sand which includes a diverse benthic fauna, including

echinoid (Gordon & Donovan, 1992) and ophiuroid (Donovan et al., in press) ossicles, crabs (Morris, in press), disarticulated chiton valves (Donovan et al., research in progress), scaphopods (Donovan & Littlewood, 1989; Donovan, 1990), gastropods and bivalves. Due to the friable nature of the sediment, two collecting methods were used. Firstly, mollusk specimens that were weath- ering out of the exposed face (figure 4) were removed manuallv. The fauna collected by this method was dom- inated by bivalves and gastropods, with three scaphopod shells. Secondly , bulk samples were collected by the bag- ful. In the laboratory these samples were emptied into shallow trays, dried in an oven overnight, then washed through a nest of sieves using cold water and redried. Sieved aliquots were then picked by ey e (coarse fractions) or under the binocular microscope (fine fractions: frac- tions finer than coarse sand were not picked). The fauna collected by this method was dominated by bivalves, gastropods and (in the finer fractions examined) chiton valves, but no further scaphopods were found. A total of 1669 benthic mollusks (excluding chiton valves; Donovan et al., research in progress) have been identified from this locality (table 1).

Locality 2

(Locality 5 of Liddell et al., 1984). This is an outcrop of hard, fine-grained, well-lithified, but occasionally chalky, limestone exposed along the shoreline as a low terrace east of the Discovery Bay Marine Laboratory, Parish of St. Ann (GR 405 569). This lithology has been interpreted as having been formed in a back reef environment (Lid- dell et al., 1984:76), presumably a lagoon, forming part of the molluscan biomicritic wackestone facies sensu stricto of Larson (1983; figure 3 herein).

Page 36 THE NAUTILUS, Vol. 107. No. 1

Table 1. Mollusk fauna collected from locality 1, east of Rio Bueno Harbour. Key: * = includes 11 juveniles, plus 2 shells not collected; ** = with apparent growth deformity; + = vaKe incomplete; ++ = probably mostly Area iiiibricala Bruguiere; S = shells or identifiable shell fragments; \' = valves; LV = left valve; RV = right valve; O = operculum; J = juvenile shells.

Gastropods

Diodora listen (d'Orbigny, 1853) 25S

Diodora '^caijencnsis (Lamarck, 1822) 12S

Diodora '■'mintitn (Lamarck, 1822) IS

Fi.ssiirclla harhadcnsis (Gmelin, 1791) IS

Acinuea ?(inlillarinn (Sowvrhy, 1831) IS

Acmaea pustidata (Helbling, 1779) 60S

Cittarium pica (Linnaeus, 1758) ,3S

Tegula fasciata (Born, 1778) ,3S

Astraea ?caelata (Gmelin, 1791) lO

Astraea tccta (Solander, 1786) 4S

Nerita versicolor Gmelin, 1791 IS

Nerita tessellala Gmelin, 1791 2S

Nerita sp. indet, j^S

Neritina virginea (Linnaeus, 1758) IS

Neritina punctulata Lamarck. 1816 2S

Littorina ?nebulosa Lamarck. 1822 2S

Alvania ?aberrans C. B. Adams, 1850 IS

Heliacus injundibulijormis (Gmelin. 1791) IS

Petaloconchus irregularis (d'Orbigny, 1842) 2S

Petaloconchus erecius Dall, 1888 IS

Petaloconchus mcgintyi Olsson and Harbison, 1953 2S

Serpulorbis decussata (CmeYm, 1791) 5S

Serpulorlris ?decussata (Gmelin, 1791) IS

Serpulorbis ?riisei (Morch, 1862) IS

Caecum ?insularum Moore, 1970 IS

Caecum plicatum Carpenter, 1858 IS

Caecum pulchcllum Stimpson, 1851 657S

Modulus modulus (Linnaeus, 1758) 13S

Cerithium ''litteratum (Born, 1778) 7S

Cerithium guinaicum Philippi, 1849 3S

Cerithium ?eburneum Bruguiere, 1792 2S

Cerithium algicola C. B. Adams, 1848 92S

Cerithium sp. 3S

Cerithium sp. indet. 3S

Hipponix antiquatus (lAnna.eus, 1767) ,3,3S

Strombus gigas Linnaeus, 1758 * 36S

Cypraea zebra Linnaeus, 1758 Ij

Cypraea cinerea Gmelin, 1791 2S

Polinices lacteus (Guilding, 1834) 9S

Morum oniscus (Linnaeus, 1767) 3S

Cymatium 'pileare' (Linnaeus, 1767) IJ

?Cymatium nicobariciim (Roding. 1798) IJ

Cymatium ?parthenopeum (von Salis, 1793) 5S

Cymatium sp. sensu lata H

^Cymatium sp. \\

Bursa cubaniarui (d'Orbigny, 1842) IJ

Columbclla mercatoria (Linnaeus, 1758) 81S

F.ngoniophos 'hmicinctus (Say, 1826) IS

?Melongena mclongena (Linnaeus, 1881) 2S

Fasciolaria tulipa (Linnaeus, 1758) 2S

Latirus ?hrevicaudatus Reeve, 1847 IS

Leucozonia nassa (Gmelin, 1791) 17S

Mitra barbadensis (Gmelin, 1791) 6S

Hyalina avena (Kiener, 1834) IS

Conus sp. or spp. 3S

?Mangelia quadrdim-ata (C. B. Adam.s, 1850) 2S

Bulla striata Bruguiere, 1792 2S

Odostomia sp. or Pyramldella sp. IS

Cheilia equestris (Linnaeus, 1758) IS

Total 1,1.3()

S. K. Donovan and D. T, J. Littlewood, 1993

Page 37

Table 1. ('diitiniird

Bivalves Area ?zebra Swainson. 18S3 Area imhricuta Bruguiere, 1789 Rarlxititi Candida (Helbling, 1779) Barlmtia ?cancellaria (Lamarck, 1819) Barhatia teiwra (C B. Adams, 1845) Anadara sp .■\rks iiuiet. + +

Brachidonti's cxustus (Linnaeus, 1758) Smoolli '•'Botida fuaca (Gmelin, 1791) iJthophaga ''nigra (d'Orbigny, 1842) hognomvn '•'alalua (CJmelin, 1791) hognomon radiatus (Anton, 1839) Isognonwn sp, indet Lima scabra (Born, 1778) Ostreola equestris Say, 1834 Codakia orbicularis (Linnaeus, 1758) Codakia ?orbiculata (Montagu, 1808) ''Codakia sp,

Chama maccrophylla Gmelin. 1791 Chama '''maccrophylla Gmelin, 1791 Pseudochatua radians (Lamarck, 1819) Americardia media (Linnaeus, 1758) Americardia guppyi (Thiele, 1910) Chione cancellata (Linnaeus, 1767) Pcrighjpta listeri (Gray, 1838) Tellina listeri Boding, 1798 Tellina sp- cf, Tellina ''tnera Sa\, 1834 Tellins indet. Tellinacean sp, indet. A Tellinacean sp, indet B ?Tellinacean sp, indet.** Areopagia Jausta (Pulteney, 1799) ?Macoma pseudomera Dall and Simpson, 1901 ?Macoma sp.

PLucinid or ?pectinacean indet. ?Mactracean indet, ?Periploma papyralium Say, 1822 Bivalve sp indet.

Scaphopods Dentalium sp cf. Dentalium (Anatalis) antillanim d'Orbigny, 1842 Dentalium (Graptaeme) semistriolatum CJuilding, 1834

9V +

1V + 1V +

1V +

1V +

Totals

4LV

77LV 25LV

ILV 36LV

ILV 32LV

4LV

ILV

lOLV

4LV ILV

2LV ILV 9LV 4LV

ILV ILV

ILV 2LV 2LV ILV

3LV

28LV

2LV

61RV

37 RV

4RV

24RV

29RV

2RV

5RV

2RV IRV

13RV 6RV IRV IRV

IRV IRV

5RV

IRV IRV 35RV IRV IRV

IRV IRV IRV 502V

19S

IS IS

2S

IS IS

3S

6S

Total

33S

IS 2S

3S

Because of the well-lithified nature of much of this limestone, it was necessary to use a hammer and chisel to remove all specimens seen in the exposed faces (figures 5-7). Specimens were not apparent on all surfaces due to the vagaries of weathering, although breaking open many of these 'unfossiliferous' exposures showed that mollusks were nevertheless common. As well as collecting individual specimens in the field, large fossiliferous slabs containing dense accumulations of mollusks were taken back to the laboratory for mechanical breakdown. A total of 1365 benthic mollusks have been identified from this locality (table 2), including abundant gastropods and bi- valves, rare scaphopods, but no chitons.

RESULTS AND DISCUSSION

Taxonomy: Taxa, and number of specimens of each species, from localities 1 and 2 are tabulated in tables 1 and 2, respectively. It is readily apparent that both fau- nas, although approximately contemporaneous and sep- arated by a distance of only about 3 km, show consid- erable taxonomic divergence (figures 8, 9). Localitv 1 has the more diverse fauna, which is dominated numer- ically by the micromollusk Caecum pulchellutn Stimp- son, 1851, arks and epifaunal gastropods (although C. piilchelltim made only a minute contribution to biomass), whereas locality 2 is typified by the occurrence of abun-

Page 38

THE NAUTILUS, Vol. 107, No. 1

Table 2. MoUusk fauna collected from locality 2, east of Discovery Bay Marine Laboratory. Key: ' C". B. .-Vdams, 1848; otherwise as for Table I

= encrusting Cerithium algicola

Gastropods Diodora ?cayenensis (Lamarck, 1822) Turbo canaliciilahi.s Hermann, 1781 Tricolia sp or spp.

?Smaragdia ciridis ciridenmris Maury, 1917 Rissoina aberans (C. B. .\dams, 1850) '^Rissoina sp.

Planaxis lineatus (da Costa, 1778) Modulus carchcdonius (Lamarck, 1822) Modulus modtdus (Linnaeus, 1758) Cerithium algicola C. B .\dams. 1848 Cerithium eburneum Bruguiere. 1792 Cerithium litteratum Born, 1778 Cerithium spp. indet. (fragments) Janthina sp.

?\iso portoricensis Dall and Simpson, 1901 Stromhus gigas Linnaeus, 1758 Polinices lactcus (.Guilding, 1834) Satica canrena (Linnaeus, 1758) Naticid sp. indet.

Cymatium "^caribbaeum Clench and Turner. 1957 Ctjmatium muricinum (Boding, 1798) Cymatium sp. indet. .\ Cymatium sp. indet. B Cymatium sp indet. C ?Thais ddtoidea (Lamarck, 1822) Columbella mercatoria (Linnaeus. 1758) Anachis obesa (C. B. .\dams. 1845) Anachis ?pretri (Duclos, 1846) Anachis sp. indet. S'assarius alhtis (Say, 1826) Fasciolaria tulipa (Linnaeus, 1758) Oliiella dealbata (Ree\e, 1850) Prttnuvi guttatum (Dill\v\n, 1817) ?\'olvarina gracilis (C B. .\dams, 1851) CoTius '^centurio Born, 1778 Conus verrucosus Hwass, 1792 ?Crassispira sp. indet. Btdia striata Bruguiere, 1792 Retusa candci (d Orbigiu, 1841)

Bivalves ??Suculid sp. indet. Area imbricata Bruguiere, 1789 Barbatia cancellaria (Lamarck. 1819) .\rk indet. sp.

Brachidontes citrinus (Boding. 1798) ?lsognomon sp. Pinna camea Gmelin. 1791 Pecten '^chazaliei Dautzenberg. 1900 ?Diplodonta punctata ^Sa>. 1822) Lucina sp. indet .A Lucinid sp. indet. .\ Lucinids spp. indet. ?Anodontia alba Link. 1807 Codakia costata (d"Orbigny. 1842) Codakia orbictdaris (Linnaeus, 175S) Codakia orbictdata (Montague. 180S) Dicaricella quadhsulcata (d"Orbign\ , 1842) Chama macerophulla Gmelin, 1791 Chama sp

Total

ILV	3RV
ILV	IRV
2L\"	IRV
ILV

IRV

ILV

1V +

ILV^	IRV
ILV
2LV	IRV
2L\-	3RV
3L\	3RV
2LV
4LV	3RV
	2RV
2LV	2RV
121.V	34RV
	IRV

2S

IS

6S

IS

IS

IS

IS

7S

IS

lOlS

3S

33S

58S

IS

35

17S

78S

IS

IJ IS IS IS IS

IJ

IS

5S

IS

IS

2S

IS

2S

37S

13S

IS

95

IS

IS

6US

IS

LOOS

IS

:i \

S. K. Donovan and D. T. J. Littlewood, 1993

Table 2. ( liiiiliinic

Page 39

fTraihyairdiinu sp

Americardia gupptji (Tliiilc. 1910)

Aniericarilia ntcdici (Linnaeus, 1758)

Lacvictirditini liHiif^iiluin (Linnaeus, 1758)

'^Lacvicardiiun Itui if^dluiu (Liiuiaeus, 1758)

Laevicardium '•'syhdnluuiu Dall, 1886

Chiotie ranci'llata (Liiuiaeus. 17(i7)

Chionc firaniilata ((iinelin. 1791)

Chionc pap}uu (Linnaeus, I7()7)

Transcnnclla '•'cimradimi Dall, 1883

Transennclla ?cubaniana (d'OrliiKny, 18-42)

Pitar allrida (Cmelin, 1791)

Tcllina altcrnala Say, 1822

Tcllina listrri Hoding, 1798

Tcllina similts Sowerby, 1806

Tcllina sp. iiulet

Apohjmelis inlastriata (Say, 1826)

Tagcliis divisus (Spengler, 1794)

Mactra fragilis Gnwhn, 1791

Scaphopods Cadulus sp

Denialium ''anlillarum dOrliigiu, 1846 Dentalium sp, (smooth-shelled)

1\

Totals

	2LV	2RV
	ILV	2RV
	(>LV	7RV	5S
	3LV	IRV'
1V +
	lOLV	URV IRV	IS
	2LV	2RV	2S
	6LV	2RV
	2LV	2RV
	13LV	12RV	6S
	2LV	2RV
2V-I-	3LV	2RV	2S
	18LV	lORV
4V-I-	7LV	3RV
	ILV		6S
	30LV	29RV 2RV	2S
		328V	25S

Total

IS 2S IS

4S

dant Bulla striata Briiguiere, 1792 and Cerithium spp with other gastropods and rarer bi\aives.

Paleoecology and preservation: Taxonomic differ- ences are interpreted as being related to paieoenviron- mental control. Locality 1 included abundant hard sub- strates for the attachment of epifaunal bivalves, provided by the coral framework, as well as a sandy substrate suitable for a variety of infaunal and epifaunal ta.xa. Chitons, which generally prefer a hard substrate, are also common at this locality . In contrast, locality 2 lacks any evidence of a three-dimensional framework structure; indeed, corals were small and isolated in this paleoen- vironment. Consequently , epifaunal species are rare and the fauna is dominated by infaunal taxa, particularly B striata, but also including \arious burrowing bi\alves (habitat preferences of many of the groups tabulated herein are summarized in Cerridwen & Jones, 1991: table

Table 3. .\ comparison of the taxonomic diversity of the extant Jamaican moliuscan fauna with nominal species identified here- in from the Falmouth Formation. Key: -I- = after Humfre\ (1975); * = excluding rare species; 1, 2 = localities.

	K\tant-I-	1	,->	1 + 2
Scaphopods	11	•1	3	4	:56
Gastropods	324*	55	37	80	25
	558	55	37	80	14
Bivalves	163*	33	34	56	34
	246	33	34	56	23
Totals	514*			141)	-">-
	831			140	17

3). The only species which forms greater than 2% of both faunas is Cerithium algicola C B .Adams, 1848 (figures 8, 9; tables 1, 2).

The difference in diversity between the localities may be real, although it is almost certainly at least part ar- tifact. This is because of the differing degrees of lithifi- cation (and, hence, availability of specimens) seen he- tween the two collecting sites. All specimens from bulk samples from locality 1 were theoretically collected by sieving and picking. In contrast, limestones from locality 2 were not amenable to such processing, being well- lithified, and liberation of specimens was essentially a destructive process. In addition to those specimens bro- ken from the rock, there were some mollusks, particularly those with a fragile shell, that were too easily lost due to breakage while others were being remo\ed. Further, many specimens were probably ne\er seen because they were enclosed within the remaining small chips of rock that were not broken down further. Micromollusks are a common component of the fauna from locality 1. main- Iv recognized during microscopic examination of the sand-sized sieve fraction. Such a technique is not gen- erally possible with the sediment from locality 2 and, even if detected, small shells are difficult to extract and clean from the hard matrix. The total absence of chiton vaKes or Caecum shells from locality 2 may be real, but the limited diversity of micromollusks from this site sug- gests that preservational and collecting biases were im- portant factors (in particular, extant Caecum is a com- mon component of seagrass communities which presumably occurred in the paleolagoon). Thus, micro- mollusks were part of the easily collectable fauna only

Page 40

THE NAUTILUS, Vol. 107, No. 1

o

o

a- o

lOOi 75 50

25 0

a

c3

H.

O

^Myf0(iiyf^'^f!f^^mKy7TmmmmmjTwTw„ym^j

Species

Figure 8. Histogram of relative abundance of mollusk species of locality 1 (n = 1467; bivalves recalculated as whole shell equivalents). 89 species are each present as less than 1% of the total mollusk fauna. • = broken fragments of arks which are too poorly preserved for even generic identiBcation, but which are probably dominantly A. inihricala.

at locality 1, although it was still possible to extract some small shells from the limestones at locality 2 (particularly robust shells such as Cadtiliis sp. and B. striata juveniles). Macromollusks from both sections are often exquisitely preserved. Whilst bivalves are normally (and chitons in- variably) disarticulated, valves often have a highly glossy appearance, such as Laevicardium laevigattim (Linnaeus, 1758) at locality 2 and Polinices lacteus (Guilding, 1834) at both localities, equivalent to that of fresh shells. Fur- ther, shell coloration and/or color banding is preserved in, for example, at least some specimens of Leucozonia nassa (Gmelin, 1791) from locality 1 and B. striata from locality 2. This indicates that the diagenetic effects lead- ing to the lithification of the limestones (particularly at locality 2) have so far had little influence on the organic molecules that are largely responsible for coloration. However, many shells are poorly preserved, often being corroded and/or abraded. Many show the influence of pre- and post-mortem boring. Pre-mortem borings by predatory gastropods (?P. lacteus) have been noted in, for example, Brachidontcs cxustus (Linnaeus, 1758) and

Table 4. ('omparison ol llic extant shallow-vsater molluscan fauna of Yucatan (PJkdale, 1974) with that of the Pleistocene

Falmouth Knrmation calitit's

e\rln<liiig chitims.

= lo-

Rocky intertidal zone (14 sp.*) Lagoonal and mangrove-associated

environments (27 sp.) Broad, shallow backreef (23 sp.) High-energy environment (8 sp.) Open sea assemblage (15 sp.) (x)smo|)olitan taxa (9 sp.)

Species	in common
	vith
		1 + 2
1 2	1 + 2	Cc)
3 1	3	21
9 9	11	41
7 10 1 1	10 1	43 13
4 3	4	27
2 4	4	44

100

o

75

e 50

o

o

25:

0

3 I

E.

c ^ 1= _3

■a	^
^	V
	-b
cc	o
<3
t-.	r^

VZ^^r77T77xy77777\^

Species

Figure 9. Histogram of relati\ e aliuntlancies of mollusk species at locality 2 (n = 1226; bivalves recalculated as whole shell equivalents) 71 species are each present as less than 2''( of the total mollusk launa. • = broken fragments of dominantly, or entirely, C. algicola + C. literattim which are too poorly pre- served for identification below the generic level.

D. sp. cf. D. (A.) antillariim (see Donovan & Littlewood, 1989) from locality 1. Presumably post-mortem borings produced by Pclionid sponges are common in arks from the same site, while B. striata and P. lacteus from locality 2 were occasionally bored by polychaetes.

Comparisons with extant faunas: 17''( of the extant, shallow-water, benthic mollusks known from the island at the present day have been identified from localities 1 and 2 (table 3). If the rarer taxa listed by Humfrey (1975) are ignored, this figure rises to 27% (table 3),

Parsons and Brett (1991) have highlighted the fluctu- ating taxonomic compositions of manv tropical, shallow shelf mollusk faunas. The assemblages described from the Falmouth Formation undoubtedly include mollusks from a number of ephemeral communities, having been collected from about 2-4 m of section. While the broad environmental signals of the two facies are obviously different, it is uncertain how the interplay of changing community structure at both sites lead to the preservation of the fossil faunas. Comparisons that we have made between our Falmouth Formation mollusk assemblages and published descriptions of Caribbean shallow-water mollusk communities have been inconclusive, showing no obvious close parallels. As an example, table 4 com- pares the Falmouth Formation molluscs with the modern shallow-water fauna of northeast Yucatan (Ekdale, 1974). There is no assemblage which shows even a 50% simi- larity to localities 1-1-2 combined. Faunal lists of the modern mollusc faunas from particular habitats in Ja- maica lia\e not been published (Dr. J.D. Woodley, per- sonal conmnication).

CONCLUSIONS

140 nominal species have been identified from the late Pleistocene Falmouth Formation of Jamaica. If rarities

S. K. Donovan and D. T. ]. Littlewood, 1993

Page 41

in the extant launa are ignored, this represents over 25% of the common living species from the island. However, the Falmouth Formation is an averaged sample from a number of ephemeral communities and comparisons w ith extant Caribbean faunas from similar em iromnents are inconclusive. This preliminary sur\ey highlights the di- versity of the mollusk fauna across reef environments and suggests that fossil reefs may be considered as im- portant sampling points during the reconstruction of an- cient regional biotas.

ACKNOWLEDGEMENTS

We thank Miss Carla M. Gordon for her considerable help in collecting samples and providing picked, moilusk- rich residues surplus to her own research needs. Dr. Rich- ard Gustafson kindly helped with the identification of some of the more obscure bivalves from locality 1. We thank Ms. Dana C. Larson for permission to utilize her thesis research in Fig. 3 This paper is Discovery Ba\ Marine Laboratory contribution number 530, New Jer- sey Agricultural Experiment Station publication number D-32501-1-92 and Institute of Marine and Coastal Sci- ences contribution number 92-04.

LITERATURE CITED

Abbott, R.T. 1954. American seashelis. Van Nostrand, Prince- ton. 542 p.

Abbott, R.T. 1958. The marine moliusks of (irand C'ayman IsiaiKJ, British West Indies. Monograpii ot the Academy ol Natural Sciences of Philadelphia 11; ISH p.

Abbott, R.T. 1974. American seashelis (2nd ed.). Van Nos- trand Reinhold, New York. 663 p.

Bengston, P. 1988. Open nomenclature. Palaeuntulogv 31: 223-227.

Cerridwen, S.A. and B. Jones. 1991. Distribution of bivalves and gastropods in the Pleistocene Ironshore Formation, Grand Cayman, British West Indies. Caribbean Journal of Science 27: 97-116.

de Jong, K.M and H.E. Coomans. 1988. Marine gastroputis from Curasao, Aruba and Bonaire Studies on the Fauna of Curaq-ao and other Caribbean Islands 69: 261 p

Donovan, S.K. 1990. Fossil Scaphopoda (Mollusca) from the Cenozoic of Jamaica. Journal of the Geological Society of Jamaica 27: 1-9.

Donovan, S.K. and CM. Gordon. 1989. Report of a field meeting to selected localities in St. Andrew and St. Ann, 25 February 1989. Journal of the Geological Society of Jamaica 26: 51-54.

Donovan, S.K., CM. Gordon, C.J. Veltkamp antl AD Scott In press. Crinoids, asteroids and ophiuroids in the Ja- maican fossil record. Geological Society of .Vmerica Mem- oir 182.

Donovan, S.K. and D.T.J. Littlewood. 1989. A Late Pleisto- cene scaphopod from Jamaica. Journal of Conchology 33: 185.

Fisher, W.S. (ed.). 1988. Disease processes in marine hi\alve molluscs. American Fisheries Society Special Publication 18: viii -I- 315 p.

Ekdale, A. A. 1974. Marine molluscs from shallow-water en-

vironments (0 t(i 60 meters) off the northeast Yucatan coast, Mexico. Bulletin of Marine Science 24: 638-668.

Gordon. CM and S K Donovan. 1992. Disarticulated echi- iioid ossicles in paleoecology and taphonomy: the last in- terglacial Falmouth Formation of Jamaica. Palaios7: 157- 166.

Hill, R.T. 1899. The geology and plusical geograph\ of Ja- maica: a study of a type of .Antillean tievelopment Bulletin of the Museum ot Coniparati\e Zoolog\ at Harvard 34: 256 p.

Humfrev. M 1975 Sea shells of the West Indies. Collins, London. .351 p.

Johnson, R.G I960. Enviromnental interpretation of Pleis- tocene marine species. Journal of Geology 68: 575-576.

Jung, P. 1972. Moliusks from the White Limestone Group of Jamaica. In: Petzall, C (ed.) Memorias de la VI Confer- encia Geologica del Caribe, Margarita, Venezuela, 6-14 del Julio de 1971, Impreso por Cromotip, Caracas, p. 465- 468.

Land, L.S. 1991. Some aspects of the late Cenozoic evolution of north Jamaica as re\ealed b\ strontium isotope stratig- raph> Journal of the Geological Society of Jamaica 28: 45-48.

Land, L.S. and S. Epstein. 1970. Late Pleistocene diagenesis and dolomitization, north Jamaica. Sedimentologv 14: 187- 200.

Larson, DC 1983. Depositional facies and diagenetic fabrics in the Late Pleistocene Falmouth Formation of Jamaica. M.S. thesis. University of Oklahoma, Norman, Oklahoma.

Liddell, W.D.,S.L. Ohihorstand AG. Coates. 1984. Modern and ancient carbonate environments of Jamaica. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Sedimenta 10: vii -I- 98 p.

Morris, PA. (W.J. Clench, ed.). 1987. A field guide to shells of the Atlantic and Ckilf Coasts and the West Indies. Houghton Mifflin, Boston, x.wiii + 330 p.

Morris, S.F. In press. Biostratigraphy of the arthropods of Jamaica. Geological Society of America Memoir 180.

Parsons, KM. and C.E. Brett. 1991. Taphonomic processes and biases in modern marine environments: an actualis- tic perspective on fossil assemblage preservation. In Don- ovan, S K. (ed ). Fossilization: the processes of taphonomy Belhaven Press, London p. 22-65.

Petuch, E.J. 1988. Neogene histor\ of tropical .American mol- iusks. The Coastal Education and Research F"oundation, C^harlottesville, Virginia. 217 p

Robinson, E. 1958. The younger rocks of St. James and Tre- lawny. Geonotes 1: 15-17.

Robinson, E. 1960. Observations on the elevated and modern reef formations of the St. Aim coast. Geonotes 3: 18-22.

Robinson, E 1963. Quaternary deposits. In. Zans, V A., L.J. Chubb, H R. Versey, J B Williams, E Robinson and D L. Cooke. Synopsis of the geologv of Jamaica. Bulletin of the Geological Survey Department of Jamaica 4: 50-54.

Taylor, J.D. 1978. Faunal response to the instability of reef habitats: Pleistocene molluscan assemblages of Aldabra Atoll. Palaeontology 21: 1-30.

Trechmann, C T. 1930. The Manchioneal Beds of Jamaica Geological Magazine 61: 199-218.

N'alentine, J.W 1989 How good was the fossil record? Clues from the Californian Pleistocene. Paleobiology 15: 83-94.

\aught, KG. (R.T. Abbott and K J Boss, eds) 1989. A clas- sification of the li\ing Mollusca. American Malacologists Inc., Melbourne, Florida, xii + 195 p.

Page 42 THE NAUTILUS, Vol. 107, No. 1

VVarmke, G.L. and R.T .Abbott. 1961. Caribbean seashells. Woodring, W.P 1928 Miocene mollusks from Bowden, ja-

Livingston, Narberth, Pennsylvania, x + 346 p. maica, pt. II, gastropods and discussion of results. Carnegie

Woodring, W.P. 1925. Miocene mollusks from Bowden, Ja- Institution of Washington Publication 385: 564 p.

maica. Carnegie Institution of Washington Publication 366: vii + 222p.

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Department of Living Invertebrates

The American Museum of Natural

History

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THE €9 NAUTILUS

CONTENTS

Volume 107, Number 2

Marine Biological LaboraLw/"'^ ^*' ^^^^ LIBRARY ^% 0028-1344

Silvard P. Kool

The Systematic Position of the Genius W&d&H HolS MasS (Prosobranchia: Miiricidae; r>r.or.o'kr;n>)p'| ^

43

Jose H. Leal Donald R. Moore

Thala csperanza. a new Costellariidae (Mollusca: Gastropoda) from northern Puerto Rico

58

Anionieto S. Tan Ya-ping Hu IVIichael Castagna Richard A. Luiz Michael J. kennish Alan S. Pooley

Shell and Pallet Mor|jhology of Early Developmental Stages of Bankia gouldi (Bartsch, 1908) (Bivalvia: Teredinidae) ...

63

S. J. kleinschusler S. L. Swink

A Simple Method tor the In Vitro Oilture of Perkinsus warinus

76

Harold G. Pierce

On the Identification of Fossil Terrestrial Gastropod Eggshells

79

THE NAUTILUS 107(2):43-57, 1993

Page 43

The Systematic Position of the Genus NiiceUa (Prosobranchia: Muricidae: Ocenebrinae)

Silvard P. Kool

Mollusk Department

Museum of Comparative Zoology

Harvard Universitv

Camhriiige. Massachusetts 02138 USA

ABSTRACT

The muricid genus S'ucclla Roding. 1798 has conimonK been placed in Thaidinae Joiisseaunie, 1888 (Prosobranchia: Muri- cidae). The Thaidinae (scnsii Kool, 1989) is monoph) letic with and thus s\ nonymous with Rapaninae Gra\ , 1853 (Kool, 1993, in press). Comparative anatomical investigations of the type species of Nucclla Roding, 1798 (Buccinum filosum Gmelin, 1791 [=Nttcella lapillus (Linnaeus, 1758)]) and of Thais Rod- ing, 1798 (Murex funis Gmelin, 1791 [ = Thais nodosa (Lin- naeus, 1758)]) as well as other rapanines have revealed that inclusion of Nucclla in Rapaninae would result in polyphyletic groups (Kool, 1989; 1993, in press). Studies of the anatomy, radula, protoconch, shell ultrastructure, and operculum of the type species of A't/ce/Za, Occnebra Gray, 1847 (Murcx crinaceus Linnaeus, 1758 [=Ocenebra erinacea]) (Ocenebrinae Coss- mann, 1903), and Trophon Montfort, 1810 {Murex magellan- tcMS Gmelin, 1791 [=Trophon geversianus (PaWni, 1774)]) (Tro- phoninae Cossmann, 1903), indicate that Nucella has close affinities with Ocenebrinae and Trophoninae Based on cladistic analyses, it is here proposed that Nucclla be placed in Oce- nebrinae. Results further reveal that the distinctions between Ocenebrinae and Trophoninae are less clear than previously accepted

Key words: Nucclla, Ocenebrinae, phylogeny; systematics; comparative anatom\

INTRODUCTION

The Thaidinae of authors, also referred to as Thaididae, Purpurinae/dae Swainsoii, 1840, Driipinae Wenz, 1941, etc., has been shown to be a conglomerate of disparate taxa (Kool, 1989; 1993, in press). The ta.xonomic coher- ence of the Thaidinae and the boundaries of its genera were based primarily on external shell characters, which are often convergent, obscuring phylogenetic relation- ships.

Rigorous cladistic analyses based primarily on char- acters derived from anatomy, radula, operculum, and shell ultrastructure, have shown that para- and poly- phyly were wide-spread in the Thaidinae/dae of authors (Kool, 1989). Subsequent phylogenetic studies have re- vealed that the genus Rapana Schumacher, 1817, and

the Thaidinae (in partem) constitute a monophyletic group, making Thaidinae a junior subjective synonym of Rapaninae (Kool, 1993, in press). The name Rapaninae will herein be used for the clade that includes Rapana and Thais

Several species of the genus Nitcella have been used extensively in ecological studies (Colton, 1922; Crothers, 1983, 1985; Emlen, 19(56; Etter, 1987; Kincaid, 1957; Moore, 1936, 1938; Palmer, 1983, 1985; Spight, 1972, 1976). In most of these studies Mucella was regarded as a subgenus or synonym of Thais. Anatomical studies (Kool, 1986, 1989) of the type species of Nucella [Buc- cinum filosum = Nucella lapillus (see Kool & Boss, 1992)] and Thais [Murex fucus = Thais noc/o.sa] revealed major differences between these genera. Kool (1988) therefore excluded Nucella from the Thaidinae and tentatively placed Nucella in the Ocenebrinae (Kool, 1989) on the basis of radular (Sabelli & Tommasini, 1987; Bandel, 1977) and protoconch (Bandel, 1975) morphology as well as anatomical descriptions (Graham, 1941) of Ocenebra erinacea.

Although the anatomv of Nucella lapillus is well known (Fretter & Graham, 1962; Kool, 1986, 1989; Oehlmann et al., 1988), relatively little is known about the soft parts of Ocenebra erinacea. Aspects of the anatomy of Tro- phon geversianus were described by Harasewych (1984), who suggested that similarities (e.g. radular morphology) between members of Trophon and Nucella may be due either to convergence resulting from similar environ- mental conditions or to phylogenetic affinity.

The object of this study is to discern the phylogenetic affinities among Nucella, Trophon and Ocenebra.

MATERIALS AND METHODS

The following specimens were used for anatomical stud- ies:

Nucella lapillus- Kittery, Maine, U.S.A. (USNM 857053) (7 9, 5S).

Trophon geversiatius; Daniel Este, Isia Grande, Tierra del Fuego, Chile (LACM 86-270.2); Puerto Basil Hall,

Page 44					THE NAUTILUS, Vol. 107, No. 2
Table 1. List of characters and character states	for Murican	•thus.	Thaifi. Troplifm. Nuce	'lla, and Ocenelna.
Character	Mur		Tha	Tro		Nuc	Oce
1. Protoconch whorls	0		0	1		1
2. Calcitic layer	0		1	1		1
3. Number of aragonitic layers	0		1	2		2	0
-4 Position of opercular nucleus	0		3	1		2
5. Opercular shape	0		1	0		1
6. Pigmentation pattern on head-foot re-
gion	0		0	1		1
7. Duct(s) for accessory boring organ and
ventral pedal gland	0		0	0		1
8. Bursa copulatrix	0		2	1		1	0
9. Seminal receptacles at dorsal periphery
of albumen gland	0		1	0		0	0
10 Fenial shape	0		2	1		0	0
11. Penial vas deferens	0		1	0		0	2
12. Prostate	0		1	0		0	0
13. Accessory salivary gland(s)	0		1	1		2	2
14. Straw-like membrane around glancl of
Leiblein	0		0	1		1	1
1.5, Posterior duct of gland of Leiblein	0		0	1		1	1
16. Ontral cusp of rachidian	0		0	0		1	1
17 Margin of rachidian basal plate	0		0	1		1	1

Isla de los Estados, Tierra del Fuego, Argentina (LACM 71-289); Piinta Catalina, Isla Grande, Tierra del Fuego, Chile (LACM 80-87.2) (4 9, 3 <5).

Ocenebra erinacea; Roscoff, France (MCZ 298425) (2 2. IS).

Morphological data were compiled from soft tissues, radulae, shell ultrastructures, protoconchs, and opercula. Living specimens of Nucella and preserved specimens of Nucella. Trophon and Ocenebra were dissected.

Radulae (2-4 per species) were cleaned using a potas- sium hydro.xide solution, rinsed in distilled water, air- dried, sputter-coated with carbon and gold, and exam- ined with a Hitachi S-570 scanning electron microscope. Photomicrographs were taken of the unused, matured central portion of each radular ribbon.

Shell fragments from at least two individuals of each species were obtained by crushing the shell. Portions from the central region of the body whorl about one- half to three-quarters of a whorl away from the edge of the apertural lip were mounted, sputter-coated with car- bon and gold, and their fracture surfaces observed with a Hitachi S-570 scanning electron microscope. An ap- parentK amorphous outer layer was interpreted as con- sisting of calcite, while layers with organization in crystal lamellar structure were considered aragonitic (data from x-ray diffraction methods confirm these identifications; Kool and Harasewych, in preparation).

Cladistic Analysis: Seventeen characters, divided into 41 character states (Table 1 ), were used in a cladistic anaK sis performed with [Iennig86 (Clopyright J.S. Farris, 1988). The six multislate characters were entered as unordered. Most characters were derived from soft tissues (mainly from the male and female reproductive and alimentarv

systems), the remainder from radulae, opercula, proto- conchs, and shell ultrastructiire. Two additional species, Thais nodosa and Muricanthus ftdvescens (Sowerby, 1841), are used in the cladistic analysis, based on data in Kool (1989; 1993, in press). Muricanthus fulvescens, a muricine and member of a sister group of Ocenebrinae, Trophoninae and Rapaninae, is used as outgroup for the cladistic analysis.

Table 1 lists characters and character states, and re- flects the sequence in which organs and other morpho- logical features are described for each of the three spe- cies.

RESULTS

DESCRIPTIONS OF TAXA

Nucella lapillus.

Shell. Protoconch (Figs. 26, 29) conical, low, of about l'/4 smooth whorls, with impressed suture; transition to teleoconch smooth, difficult to discern. Teleoconch high- ly polymorphic; usually elongate, oval, of 6-7 whorls (Figs. 1-6, 21, 22). Adult shell to 55 mm in height, 30 mm in u idth. Body whorl rounded, about 80?f of shell height, smooth or sculptured with pattern of about 15 spiral, occasionally lamellose. ridges. Aperture (to 65% of shell height) oval; outer lip w ide, smooth, occasionally with 3-4 denticles on edge of thickened lip. Columella v\ith moderate callus, flat to concave. Siphonal canal short, open (Fig. 3) to partly closed (Fig. 1). Siphonal fascicle poorly developed, adjacent to callus layer. Shell color variable: white, grey, yellow, brown, orange-red; often banded; aperture, colmiiella white

Shell Ultraslrncturc. Innermost laverof crossed-lamellar

S. p. Kool, 1993

Page 45

aragoiiite, with crystal planes oriented perpendicular to growing edge [15-20% of tliiekness; often absent (Fig. 28)]; middle layer of crossed-lamellar aragonite. witfi crystal planes oriented parallel to grow ing edge [15-25% of thickness]; outermost laser of calcite [55-85%) of thick- ness] (Fig, 27).

Operculum D-shaped, with lateral nucleus just below center right (Figs. 7, 8). Outer surface (Fig. 7) with arch- shaped growth lines recurved at both ends; inner surface (Fig. 8) with 3-5 arch-shaped growth lines, with broad (35-40% of opercular width), callused, glazed outer rim

HeocI and Foot. L'niformly light yellow to white. Ce- phalic tentacles elongate, thin. Incurrent siphon short. Mantle edge smooth. Accessory boring organ (Fig. 56, abo) large, well developed, (in females) anterior to, sep- arate from equally large ventral pedal gland (Fig. 56, Pg)-

Mantle Cavity Osphradium slightK more than 'i cten- idial length, less than l; ctenidial width. Right pectin usually wider than left. Each lamella (8-10/mm) at- tached to mantle roof along V2 its base. Anteriormost portion of ctenidium straight, extending slightly anterior of osphradium Ctenidial knnellae (9-1 1/mm) wider than high or equalK wide as high, with strongly convex or straight lateral edges, translucent. Thick supporting rod extending beyond lateral edge of each lamella, forming small papilla.

Female Reproductive System: Vaginal opening round with slightK swollen edges, located below and posterior to anus. Bursa copulatrix (Fig. 47, 48, be) small diver- ticulum, connected to vagina, ventral channel (vc) by wide ventral passage. Ventral channel formed by two small interlocking flanges located under ventral lobe of capsule gland, one arising from left lobe, the other from ventral epithelium. Single-chambered ingesting gland lo- cated between capsule gland and albumen gland. Al- bumen gland (Fig. 49) arch-shaped, elongate, opening anteriorly into ovi-sperm duct (osd), posteriorly into ovi- duct (od). Ovary yellow to light golden. Many specimens with pseudo-penis of variable size (see also Brvan et al., 1986).

Male Reproductive System: Penis (Fig. 60) simple, elon- gate, dorso-ventralK flattened, often slightK curved, w ith abruptly tapering, papilla-like end. Penial vas deferens (Fig. 62, pvd) minute, simple duct, semi-closed by trans- verse ridges on overlapping ventral and dorsal sides of penis. Cephalic vas deferens (Fig. 57, cvd) well devel- oped, extending from penis (p) to prostate gland (pr). Prostate gland (Fig. 57, pr) white; prostate duct (prd) dorso-ventral slit in cross section; duct open to mantle cavity posteriorly. Posterior vas deferens (along visceral mass) well developed, white to dirty white, iridescent. Testis light brow n to golden.

Alimentary System: Paired accessors salivar\ glands ex- tremely long, usually equal to or slightly longer than one- half of shell height; left gland intertwined with salivary

glamls, right gland separate from salivary glands, situ- ated in right anterior corner of buccal cavity. Salivar% glands in center of dorsal buccal cavity between gland of Leiblein and short, pear-shaped valve of Leiblein. Sali\ar> ducts attached to anterior esophagus at some distance from valve. (Glandular folds in mid-esophageal region inconspicuous. Connection between mid-esoph- agus and gland of Leiblein short, thick. Posterior esoph- agus appressed to left side of gland of Leiblein in loop- shaped fashion. Gland of Leiblein \ellowish; posterior blind duct very short ( < Vi length of gland), with small terminal ampulla. Stomach tubular, with 8-12 large, ra- dialK oriented folds on wall. Stomach typhlosole ex- tending dorsally onto left portion of posterior mixing area. Intestinal t\ phlosole thick, w ide. Tw o digestive di- verticula present. Rectal gland inconspicuous. Large pa- pilla overlying equally large anus.

Radula: Ribbon length 30-35% of shell height. Base of rachidian tooth expanded below fwse of neighboring ra- chidian tooth; central cusp of rachidian thin, flame- shaped, leaning more anteriorly (in situ) than lateral cusps; inner lateral denticle low on base of lateral cusp, occasionalK bifurcate (w ithin same specimen); outer edge of lateral cusp w ith se\ eral denticles; large marginal cusp pointing straight forward and parallel to elongate, lateral extension at base of rachidian tooth (Figs. 23-25), re- sulting in bifid appearance of rachidian basal plate. Lat- eral teeth shorter than rachidian width (Fig. 23).

Egg capsules: Elongate-oval, vase-shaped, up to 9 mm in height, 3 mm in w iilth. Capsules \ellow, light brow n or purple (Lebour, 1937), each attached by short, thin stalk about 1 mm long. Apex tapered with rounded, cap- shaped top with mucous plug. Capsules interconnected at base. Number of embryos varying from two (Risbec, 1937) to one thousand (Fretter & Graham, 1962, 1985), most being nurse eggs (75-95%) (Crothers, 1985; Fretter & Graham, 1985; Lamv, 1928) (see also Pelseneer, 1911; Ankel, 1937; Thorson, 1941, 1946; Robertson, 1974).

Ecology: More is known about Nucclla ecology than about any other muricoidean [for an extensive bibliog- raphy on the biology (primarily ecology) of Nticella la- pillus, see Crothers, 1985]. Nucella lapUlus and its west- ern American congeners have been the topic of man\ comprehensive studies (Crothers, 1985; Emien, 1966; Et- ter, 1987; Kincaid, 1957; Spight, 1972). Nucella feeds on barnacles and mussels (Colton, 1922; Connell, 1970; Crothers, 1973; Graham, 1955; Kool, 1987; Largen, 1967; Murdoch, 1969; Spight, 1982) in the rocky intertidal zone and is eaten by crabs and birds (Spight, 1976). Studies of Agersborg (1929), Colton (1922), and Moore (1936) show that environmental factors (wave action, food avail- abilits, etc.) influence shell morphology. Moore (1938) reported the main spaw ning period to be during winter and spring; but breeding occurs throughout the year (Lebour, 1937; Thorson, 1946). Juveniles hatch from the eggs after 4-7 months (Fretter & Graham, 1985).

Distribution: North Atlantic Ocean from southern Por-

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7

^^^

%

^^^

/ ■

/.

11

8

mi'

17

^^m

'^'

18

19 *-

Figures 1-8 .V«C(?//a /api7/us. 1-6. Shells (1,2 MCZ 69192, Freshwater Bay. Isle of Wright. England, height 25 mm; 3,4 MCZ 1 1.509.3. Sullivan, Maine. I S .V . height .35 mm; 5.6 MC.Z 50600. Wales, height 3-1 mm) 7.8 Operculum (MCZ 302404, Braunton, North Devon, England, height 15 mm); 7. Outer surface; 8. Inner surface. Figures »J-14 Trophon gevcrsianus. Shells (9.10 MCZ

S. p. Kool. 1993

Page 47

tugal to Xovaya Zembl\a [records from western Medi- terranean, Azores, Morocco, Senegal, and Canary Islands are suspect (Cooke. 1915)]; Great Britain; Ireland; Ice- land; Greenland; New Jerse\, L.S.A.. to northern Canada [for extensi\e list of geographical range and localities, see Cooke, 1915].

Trophon geversianus:

Harasewych (1984) described aspects of the anatom\ of Trophon geversianus (Figs. 9. 10, 13, 14. 30. 31 ). Because my observations were congruent w ith the descriptions in Harasewych s paper, only the most essential and supple- mental data are presented to avoid unnecessary dupli- cation.

Shell ultrastructure: Innermost la\er of crossed-lamellar aragonite, w ith cr> stal planes oriented perpendicular to growing edge [10-15!^ of thickness; often absent (Fig. 37)]; middle layer of crossed-lamellar aragonite, with crystal planes oriented parallel to growing edge [15-20% of thickness]; outermost layer of calcite [70-80% of thick- ness] (Fig. 36).

Operculum: 0\ate, with lateral nucleus in lower right (Figs. 11, 12). Outer surface (Fig. 11) with growth lines recurved at upper ends, progressiveh upright; inner sur- face (Fig. 12) with 3-4 narrow horseshoe-shaped growth lines, broad ( > '3 opercular width ). lightK callused, glazed outer rim.

Head and foot: UniformK light \ellow Cephalic ten- tacles elongate, thin. Incurrent siphon short. Mantle edge smooth, .\ccessory boring organ (Fig. 55, abo) well de- veloped, sharing common duct with ventral pedal gland (pg) in females.

Mantle Cavity: Osphradium small ('/3-% ctenidial length. -/i ctenidial width). usualK partialK overK ing ctenidium. Right pectin usualK wider than left. Each lamella (9- 10 mm) attached to mantle roof along most of its length. .•\nteriormost portion of ctenidium straight, extending slightly anterior of osphradium. Ctenidial lamellae (10- 12 mm) translucent, wider than high anteriorK. equalK wide as high posteriorly, with straight to convex lateral edges.

Female Reproductive System: \'aginal opening (Fig. 47, vo) round, with swollen edges, located below, slightly anterior to anus. Bursa copulatrix (Figs. 47, 48, be) small diverticulum, connected to vagina and ventral channel (vc) by wide duct. Wall of posterior vagina with folds decreasing in number posteriorly. Capsule gland with simple, inconspicuous ventral channel posteriorly con- nected to large, well-de\eloped ingesting gland filled

with w hitish substance. .Albumen gland (Fig. 49) large, arch-shaped, elongate, opening anteriorly into ovi-sperm duct (osd), posteriorly into oviduct (od).

Male Reproductive System: Penis (Fig. 59) bulbous, short, dorso-\entrall\ flattened, w ith large papilla. Penial vas deferens (Fig. 62. p\d) minute, simple duct, closed by overlapping ventral and dorsal sides of penis. Cephalic vas deferens (Fig. 57, cvd) well developed. Prostate gland (Fig. 57. pr) light yellow; prostate duct (prd) dorso-ven- tral slit in cross section; duct open to mantle cavit\ pos- teriorly.

Alimentary System: Paired accessory- salivar\ glands short (<1 10 shell height); left gland intertwined with left salivary gland, right gland free, situated in right anterior corner of buccal cavity. Salivary glands in center of dorsal buccal ca\it\ between gland of Leiblein and elongate \al\e of Leiblein. Salivar\ ducts attached to anterior esophagus immediately anterior to \alve. Glandular folds in mid-esophageal region well developed. Connection betw een mid-esophagus and gland of Leiblein short, thick. Posterior esophagus appressed to left side of gland of Leiblein in loop-shaped fashion. Gland of Leiblein yel- low ish; posterior blind duct short, without terminal am- pulla. Stomach tubular, with 10-15 thin, elevated folds on w all; posterior ones oriented toward center, anterior ones merging into elevated section of sorting area. In- testinal typhlosole thin. Two digestive diverticula pres- ent. Rectal gland light brown, extending along '2 of pal- lia] gonoduct.

Radula: Ribbon length 40-45% of shell height. Base of rachidian tooth expanded below base of neighboring ra- chidian tooth; central cusp thin, with wide base; inner lateral denticle small protrusion from base of lateral cusps; outer edge of lateral cusp straight, with several faint denticles; large marginal cusp pointing straight forward and parallel to faint, elongate, lateral extension at base of rachidian tooth (Figs. 32-34), resulting in bifid ap- pearance of rachidian basal plate. Lateral teeth shorter than rachidian width, with wide bases positioned close together (Fig. 32).

Egg capsules: Discoidal, lateral!) flattened, with wide, equalK flattened base, up to 20 mm in height (including base), 12 mm in width (Harasewych, 1984, Fig. 23). Capsules yellowish in color, and containing 74-112 em- bryos (MeKill & Standen, 1898). Capsules deposited in row s w ith flattened edges adjacent to one another (Lamv, 1928; D'Asaro, 1991).

Ecology: This species lives in the rocky intertidal and subtidal zones where barnacles and mussels are plentiful.

10941.3. Ushaia, Tierra del Fuego, Argentina, height 41 mm; 1:{.I4 MCZ 1-32566. Falkland Islands. Argentina, height 47 mm). 11.12 Operculum iLACM 86-270.2, Daniel Este. Isla Grande. Tierra del Fuego. Chile, height 11 mm); 11. Outer surface; 12. Inner surface. Figures 15-20 Ocenebra erinacea. Shells (15.16 MCZ 87662. \Ve\mouth. England, height 31 mm; 19,20 MCZ 1724.50. Fos-sur-Mer. Bouches-du-Rhone, France, height 56 mm) Operculum (17.18 MCZ 302405, St. Lunaire. France, height 8 0 mm); 17 Outer surface; 18. Inner surface.

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THE NAUTILUS, Vol. 107, No. 2

Figures 21-29 \ucclla lapillus. 21,22 Shell (MCZ 09192, Freshwater Bay, Isle ot Wight, England, height 2.5 1 mm). 23-2.S Kadiila (ISNM 8.570.53, Kittery, Maine, LI.S.A.). 23. Clentral portion of radular ribbon. Scale bar = 15 fim. 24 Rachidian teeth Scale bar = 10 ^m. 25. Side view of rachidian teeth (right row of lateral teeth removed). Scale bar = 10 fim. 26,29 Protoconch (MCZ 14184, Isle au Ilaut, Maine, U.S.A.). 26. Apical view. Scale bar = 12 m"' 29. Side view. Scale bar = 12 ^m 27,28 Shell ultrastructure (view of growing edge; innermost layer on bottom) (MCZ 69192, Freshwater Ba>, Isle of Wight, England) Scale bars, 4.5 ixn\ and 70 niu, respectively.

S. p. Kool, 1993

Page 49

Figures 30-38. Troplion gcicrsianns. 30.31. Sliell (MC^Z 1.32566. Falkland Islands, Argentina, lu'iglit -JT mm). 32-3 4-. Radula. (LACM 86-270.2. Daniel Kste. Isia Grande. Tierra del Fuego. Chile) 32. Central portion of radiilar ribbon. Scale bar = 45 nm. 33. Rachidian teeth Scale liar = 25 ^m. 34 Side view of rachidian teeth. Scale bar = 20 ^in 35,38. Protoconch (LACM 86- 270.2, Daniel Este, Isla Grande, Tierra tlel Fuego, Chile). 35. Apical view. Scale bar = 150 ^m. 38 Side view. Scale bar = 150 Mm 36.37 Shell ultrastructure (L.ACM 86-270 2, Daniel Fsle. Isla (Iraiide, Tierra del F'liego, Chile); Scale bars, 60 fim and 150 Mm, respectivel)

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Fif^ures 39-46. Ocenebra crinai-ciL 39,40, Sliell (MCZ 172450, Fos-sur Mer, Botichfs-dii-Hlioiu", France, height 56 mm) 41-43 Kathila (MCZ 298425, Roseoll, France). 41 Oenlral portion of rihhoii Scale bar = 17 ^ni 42. Rachichan teeth Scale bar = 8 ^m. 43 Side view of rachidian teeth. Scale bar = 9 m"i 44.46 Protoconch (MC:Z 38369, Kent, Fngland) 44. .Apical view. Scale bar = 9(1 A/ni 46 Side view. Scale bar = 90 niu 45 Shell iillrastnictiire (MCZ 298425, Roscoff, France), Scale bar = 1.30 ^m.

S. p. Kool, 1993

Page 51

Figures 47-56. Anatomical structures of the female repro- ductive system of Nitcella lapilltis. Trophon geversianus, Oce- nehra erinacea, Muricanthus fulvescens. and Thais nodosa.

47.50.53. Bursa copulatrix in iV lapillus and T. geversianus (47), Th. nodosa (50), O erinacea ami M. fulvesccns (53).

48.51.54. Cross sections through bursa copulatrix (location indicated b>' vertical bar). 49,52. Albumen glands in N. la- pillus. T gever.'iianus. O erinacea. M Julvescens (49), anil Th. nodosa (52), 55,56. Sagittal section through foot showing accessory boring organ and pedal gland of Th. nodosa, T geversianus, M. julvescens (55), N . lapillus. and O. erinacea (56).

abo, acces.sory boring organ; be, bursa copulatrix, db, duct to bursa copulatrix; leg, left lobe of capsule gland, od, oviduct, osd. ovi-sperm duct; pg, ventral pedal gland; p,sr. posterior seminal receptacles, rcg. right lobe of capsule gland, tf, transverse fold; vc. ventral channel, \cf, flange of the ventral chaiuiel, vo. vaginal opening.

Sculpture of the shell may vary v\ itli the t\ pe ot habitat

Distribution: Southern Argentina to Chile.

Ocenebra erinacea:

Shell: Protoconch (Figs. 44, 46) conical, low, of l'/2 smooth whorls, and with impressed suture; transition to teleo- conch smooth, difhcult to discern. Teleoconch elongate, fusiform, biconical (Figs. 15, 16, 19, 20, 39, 40), of 7-8 whorls. Adult shell highly variable in shape, to 55 mm in height, 25 mm in width (not including spine length; 35 mm including spine length). Body whorl 55-60?c of shell height, with 3-9 varices, often with frilled edges, and with (3-8 spiral cords. Aperture (to 30% of shell height) round to oval; outer lip with crenulated edge Moderately callused columella. Siphonal canal partly or completely closed, often nearly equal in length to aperture in larger

Figures 57-64 .■\nal<imical structures ol the male rcjiroductive system of S'ucclla lapillus. Trophon geversianus. Ocenebra erinacea. Muricanthus fukescens, and Thais nodosa. Prostate gland with proximal and distal cross sections in N. lapillus. T. geversianus. O erinacea, M . julvescens (57) and Th. nodosa (58). Penial morphologies with cross sections in T. geversianus (59.62), N. lapillus. M. fulvesccns {f>0,b2). O erinacea (60.63), and Th nodosa (61,64).

b\ , blood vessel, cvd, cephalic vas deferens; p, penis, pr, prostate, prd, duct through prostate, pvd, penial vas deferens.

specimens. Siphonal fasciole pointing away from si- phonal canal. Shell color yellov\ish to cream or dark brown; aperture, columella white.

Shell ultrastructure: Innermost layer of crossed-lamellar aragonite, with crystal planes oriented perpendicular to growing edge [15-20% of thickness]; followed by layer of crossed-lamellar aragonite, with crystal planes ori- ented parallel to growing edge [40-45% of thickness]; followed by layer of crossed-lamellar aragonite, with crystal planes oriented perpendicular to growing edge [5-8%. of thickness]; outermost layer of calcite [35%. of thickness] (Fig. 45).

Operculum: D-shaped, with lateral nucleus in lower right (Figs. 17, 18). Outer surface (Fig. 17) with arch-shaped growth lines progressively upright, recurved at upper end; inner surface (Fig. 18) with 4-5 arch-shaped growth lines, w ith broad (~ Vz opercular w idth), lightly callused, glazed outer rim.

Head and foot: I'niformly light yellow to white. Ce- phalic tentacles elongate, thin. Incurrent siphon well de- veloped. Mantle edge smooth, occasionally with crenu- lations (possibly an artifact). Sole of foot w ith large lateral

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THE NAUTILUS, Vol. 107, No. 2

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Fipurp 65 Cladciyram, based on analysis of data in Table 1, shduiiig high |)ii\l()geiietic affinity between Nucclla and Oce- nebra. Numbers next to character changes correspond to num- bers given to characters in Table 1. Alternative, equally par- simonious character state transformation series are possible for characters 3, 4, 5, and 8 (see text).

folds. Accessory boring organ (Fig. 56, abo) large, well developed, (in females) anterior to, separate from equally large ventral pedal gland (Fig. 56, pg).

Mantle Cavity. Ospliradium (<'/2 ctenidial length, % ctenidial width) partially extending over ctenidium. Right pectin usually wider than left. Each lamella ( 10-1 l/mm) attached to mantle roof along short basal portion. An- teriormost portion of ctenidium straight, extending an- teriorly of osphradium. (Ctenidial lamellae (11-12/mm) basically triangular, longer than high w ith convex lateral edges posteriorly. Lamellar support rods not well devel- oped.

Female Reproductive System: Vaginal opening (Fig. 53, vo) round to elongate, on short, extension of pallial gon-

oduct, situated below, posterior to anus. Bursa copulatrix (Figs. 53, 54, be) large diverticuhmi (equal in diameter to capsule gland), connected at its anterior portion to duct running parallel to ventral channel for some length prior to connecting with it (Figs. 53, 54, db). Lumen of bursa copulatrix Oiled w ith loose flocculent material and iridescent spherules. Capsule gland posterior to, shorter than bursa copulatrix. Ventral channel (Figures 53, 54, vc) well developed anteriorly, less distinct posteriorly. Ingesting gland situated between capsule gland, albumen gland. Albumen gland (Fig. 49) arch-shaped, elongate, opening anteriorly into ovi-sperm duct (osd) posteriorly into oviduct (od). Ovary orange-yellow. Pseudo-penis oc- casionally present (see also Feral, 1976).

Male Reproductive System. Penis (Fig. 60) simple, dor- so-ventrally flattened, elongate, slightly curved, with abruptly tapering, papilla-like end. Penial vas deferens (Fig. 63, pvd) a wide, straight tube star-shaped in cross section; tube partialK attached to penial wall Cephalic vas deferens (Fig. 57, cvd) large, similar to penial vas deferens in structure, extending from penis (p) to prostate gland (pr). Prostate gland (Fig. 57, pr) white to yellow; prostate duct (prd) a dorso-ventral slit in cross section anteriorK , a triangular large space posteriori)-; duct open to mantle cavity posteriorly (Fig. 57). Posterior vas de- ferens white to dirty white, iridescent. Testis yellowish.

Alimentary System: Paired accessory salivary glands very long (* '/2 shell height); left gland intertwined with left salivary gland, right gland free, situated in right anterior corner of buccal cavity. Salivary glands in center of dorsal buccal cavity between gland of Leibleiii and short, pear- shaped valve of Leiblein. Salivary ducts attached to an- terior esophagus at short distance from valve. Glandular folds in mid-esophageal region swollen, especially well developed at connecting point between esophagus and gland of Leiblein. C-onnection between mid-esophagus and gland of Leiblein short, thick. Posterior esophagus appressed to left side of gland of Leiblein in loop-shaped fashion. Gland of Leiblein yellowish; posterior blind duct very short (<V2 length gland of Leiblein), with promi- nent terminal am|Milla. Stomach tubular, w ith faint folds on stomach wall oriented tow ard center of stomach (poorly preserved in specimens examined). Rectal gland thin, green, extending along V2 oi pallial gonoduct. Large pa- pilla overla\ ing anus

Radula: Riblion length 35-40% shell height. Base of ra- chidian tooth expanded below base of neighboring ra- chidian tooth; central cusp of rachidian thin, flame- shaped, leaning more anteriorly (in situ) than lateral cusps; inner lateral ilenticle low on base of lateral cusp, occasionally bifurcate (w ithiii same specimen); outer edge of lateral cusp straight, with several short denticles; large marginal cus() pointing straight forward and parallel to elongate, lateral extension at base of rachidian tooth (Figs. 41-43), resulting in bihd appearance of rachidian basal plate. Lateral teeth with narrow base, wideK spaced, shorter than rachidian width (Fig. 41).

S. P Kool, 1993

Page 53

Egg capsules: Oval-elongale, vase-shapt-il, trianuulai in cross section. Capsules \ell()\visli, up to 13 mm in lu-iulit, 6 mm in width, each on narrow stalk, attached b\ Hat base. Apex with short elevated protuberance with mu- cous plug Each capsule containing 4-167 embryos, of which none are nurse eggs (Fretter & Graham, 1985; Lebour, 1937).

Ecology: Occncbra crinacea li\es in the rocky intertidal and subtidal zones (Jeffreys, 1867) to 150 meters (Fretter & Graham, 1985) where it feeds on oysters and other bivalves (Fretter & Graham, 1985), barnacles ami limpets (Graham, 1955). Lebour (1937) reported tireediiii; in late spring ant! summer Juveniles hatch from the eggs after 12-14 weeks (Fretter & Graham, 1985). A comprehensive ecophysiologicai study was done on Ocenebra erinacea by Hawkins (1985)

Distribution: Nfirth Atlantic Ocean (Spain to Norway, Great Britain, Ireland); Mediterranean Sea (southern Eu- rope, northern Africa).

CLAPISTIC ANALYSIS

The cladistic analysis yielded one tree with a consistency inde.x of 0.88 (Fig. 65). This cladogram indicates that: 1) placement of \ucclla in Thaidinae or its senior syn- on\ ni, Rapaninae, creates polyphyletic groups (see also Kool, 1989); 2) Nucclla is more closely related to Oce- nebra than to Troplwn and should be placed in Oce- nebrinae; 3) the subfamilial boundaries between Oce- nebrinae and Tro[)honinae are much less distinct than previousK accepted.

Characters and character state distribution among the taxa Nucclla. Trophon. Ocenebra. Thais, and the out- group, Muricanthus:

Character 1. Protoconch: 0. multispiral ( > 2 whorls); 1, paucispiral (< 1': whorls).

Nucella. Trophon and Occncbra (Figs. 26, 29, 35, 38, 44, 46) have a paucispiral, smooth protoconch without a sinusigeral notch or outwardly-flared lip. This morphol- ogy reflects direct development. The outgroup and the rapanines have a multispiral (and generalK sculptured) protoconch w ith a sinusigeral notch and outwaril-tlaring lip, t\pical for species v\itli a pianktonic larval stage.

Character 2. Calcitic layer; 0. absent; 1. present.

The outgroup lacks an outer calcitic shell layer that is present in the other four ta.xa. The presence of calcite appears to be the derived condition.

Character 3. Number of aragonitic layers: 0. 3; 1. 4; 2. 2 The outgroup and Ocenebra have three layers of ara- gonite (transverse, collabral, transverse), Thais has an additional, innermost fourth layer of crystals oriented in a 45° angle; both Nucella and Trophon have two layers (transverse, collabral), but may lack the innermost trans- verse layer (Figs. 28, 37).

Character 4. Nucleus of operculum: 0. terminal nucleus in lower right; 1. lateral nucleus in lower right; 2. lateral

niiclfus licldw center right; 3 lateral nucleus in center right.

The outgroup has a terminal nucleus in the lower right. .All iiigroup taxa have a lateral nucleus, the position of w Inch varies. The nucleus of the operculum in Nucella is located below the center right; that of Trophon and Ocenebra in the lower right (Figs. 7, 11, 17, respectively). The nucleus is located in the center right in rapanines.

C;haracter 5, Shape of operculum: 0. oval; 1. D-shaped. The opercula of Nucella, Thais, and Ocenelna are roughly D-shaped Those of Muricanthus and Trophon are elongate-oval.

(Character 6, Pigmentation pattern of head-toot region: 0 jjresent; flecked with black and gra\; 1. absent, uni- formly colored (faint yellow ).

The head-foot regions of Nucella, Trophon, and Oce- nebra are uniformly faint yellow. Both Thais and the outgroup are densely flecked with black blotches and specks (this pattern generalK survives preservation in alcohol although other colors, such as white and yellow, fade).

Character 7. Ventral pedal gland and accessory boring organ: 0. sharing one duct; 1. with separate ducts.

In Nucella and Ocenebra, the accessory boring organ and ventral pedal gland (Fig. 56, abo, pg) have separate ducts to the sole of the loot, while in Trophon, rapanines, and the outgroup these structures share a common duct (Fig. 55, abo, pg).

CJiaracter 8. Bursa copulatrix: 0. large diverticulum, sep- arate from capsule gland; 1. small diverticulum, separate from capsule gland; 2. small chamber with lumen con- tinuous with capsule gland.

The bursa copulatrix is a small blind sack in Nucella and Trophon (Fig. 47), a large separate diverticulum in Ocenebra (Fig. 53) and the outgroup, while in rapanines the bursa is continuous with the capsule gland (Figs. 50, 51).

Character 9. Seminal receptacles at dorsal periphery of albumen gland: 0. absent; I. present.

In Thais, a row of posterior seminal receptacles (Fig. 52. psr) at the dorsal periphery of the albumen gland presumably increases efficiency in the fertilization pro- cess (Kool, 1988, 1989). These posterior seminal recep- tacles are absent in Nucella, Trophon. Ocenebra. and in the outgroup, Muricanthus (Fig. 49). This character is a synapomorphy for Rapaninae (Kool, 1993, in press).

Character 10. Penial shape: 0. simple, elongate to lightly curved; 1. bulbous, with papilla; 2 strongK recurved with pseudo-papilla.

Penial shape in Nucella. Ocenebra. and the outgroup is elongate (F"ig. 60). The penis in Thais is strongly recurved, and sinuous (Fig. 61), while that of Trophon is short, bulbous, with a distinct papilla (Fig. 59).

(Character 11 Penial \as deferens: 0. simple duct; 1. small, loose duct-w ithin-a-duct; 2. large duct-within-a- duct, partialK attached to penial iiuier wall

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THE NAUTILUS. Vol. 107, No. 2

Nucella, Trophon and the outgroiip have a peiiial vas deferens that is loosely closed, while rapanines have a ■■duct-vvithiii-a-duct" system (Figs. 61, 64) (Kool, 1988, 1989). Ocenehra differs from both types in having a rather wide inner duct that is partially attached to the penial inner wall (Fig. 63).

Character 12. Prostate Gland: 0. open to mantle cavity posteriorly; 1. without opening to mantle cavity.

Males of Nucella. Trophon. Occnelrra. and the out- group have a prostate gland that is open to the mantle cavity along its posterior portion (Fig. 57). The prostate of rapanine males does not open to the mantle cavity (Fig. 58).

Character 13. Accessory salivary gland length: 0. right gland small, left gland absent; 1. glands < '/i shell height; 2. glands > V2 shell height.

Character 14. Straw-like membrane around gland of Leiblein: 0. present; 1. absent.

In most rapanines and the outgroup, the gland of Leib- lein is covered by a thick membrane of interwoven fibers of connective tissue, producing a straw-like appearance. Such a membrane is absent in Nucella. Trophon and Ocenehra.

Character 15. Posterior duct of gland of Leiblein: 0. longer than Vz of gland length; 1. shorter than V2 gland length.

In Nucella, Trophon and Ocenehra. the gland of Leib- lein tapers posteriorly into a thin, very short posterior duct that runs adjacent to the posterior esophagus and is often filled with secretory material from the gland; in the majority of rapanines and in the outgroup this duct is much longer, extending into the dorsal branch of the afferent renal vein.

Character 16. Central cusp of rachidian: 0. oriented in same plane as lateral cusps; 1. leaning more anteriorly than lateral cusps.

In Nucella (Fig. 25) and Ocenehra (Fig. 43) the central cusp on the rachidian leans more anteriorly (in situ ) than the lateral cusps. In Thais. Trophon (Fig. 34), and the outgroup, the lateral cusps and central cusp are aligned in the same plane.

Character 17. Margin of rachidian basal plate: 0. straight; 1. bifid.

The bifid condition of the rachidian basal plate (Figs. 25, 34, most developed in Fig. 43) is found in Nucella, Trophon and Oceneina, but not in Thais or the outgroup.

Synapornorphies for the Nucella-Ocenehra clade {Fig. 65):

Character 5: The character for opercular shape is ho- moplastic; a D-shaped operculum occurs in Thais as well.

C]haracter 7: Both Nucella and Ocenehra have separate openings for the ventral pedal gland and accessory boring organ (Fig. 56, abo, pg). Female specimens of Trophon geversianus, Thais nodosa, and the outgroup, have a single duct and opening for these organs (l"ig. 55, abo.

pg). A shared duct for the accessory boring organ and ventral pedal gland, as found in Trophon geversianus, may not be as advantageous as an arrangement as w hen the ducts originating from the accessory boring organ and ventral pedal gland are separate. It would appear that an arrangement where one duct serves both as ven- tral pedal gland and as a passage for the accessory boring organ and its secretions during boring activities (Carri- ker, 1981) prevents the female from boring activity, and thus perhaps feeding in general, during stages of egg- laying.

Character 13: Nucella and Ocenehra have a pair of very long accessory salivary glands (> ','2 shell height). Tro- p/!o;(andT/ia!shavemuchsmallerglands(< '/^ shell height). The outgroup has only one extremely small right acces- sory salivary gland.

Character 16: In Nucella, and to a much greater degree in Ocenehra, the central cusp leans more anteriorly (Figs. 25, 43, respectively) (in situ) than the lateral cusps, whereas in Trophon, the central cusp is aligned with the lateral cusps (Fig. 34).

Synapornorphies for the Trophon-Nucella-Ocenehra Clade:

Character 1: The paucispiral protoconch is indicative of having crawl-away larvae, rather than a planktonic larval stage that is found in Thais and other rapanines (Kool, 1993, in press) and the outgroup.

Character 4: The cladogram suggests that an opercular nucleus below the center right (Nucella; character state 2) evolved from the ancestral condition for the taxa in this clade of having a nucleus in the lower right (Oce- nehra and Trophon; character state 1).

Character 6: All three taxa lack a pigmentation pattern on their head-foot region that is found in the outgroup, Thais, and other members of the Rapaninae.

Character 14: The straw-like outer membrane of the gland of Leiblein is absent in the species of this clade, but present in the outgroup, and most members of Ra- paninae (Kool, 1989; 1993, in press).

Character 15: The posterior duct of the gland of Leiblein is shorter than V2 the length ot the gland itself in this clade, but much longer in the remaining taxa, reaching into the dorsal branch of the afferent renal vein.

Character 17: The bifid condition of the basal plate, especially well developed in Ocenehra (Fig. 43), is absent in Thais and the outgroup.

Synaponiorphics for the Thais-Trophon -Nucella-Oce- nehra Clade:

Character 2: An outer layer of calcite is present in all ingroup taxa, but is absent in the outgroup.

Character 13: The outgroup has only one extremely small right accessory .sali\ar> gland. A situation of having a pair of medium-size accessory salivary glands appears to

S. p. Kool, 1993

Page 55

have evolved from the condition described above and to have given rise to the most deri\ed condition (extremely long glands).

DISCUSSION

According to the topology of the cladogram (Fig. 65), two characters have evolved in a parallel manner in Nucella lapillus and Trophon geversianus. Out of the context of the cladogram, these similarities would suggest a closer relationship between these two species than is suggested by the tree topology:

Character 3: Shell ultrastructure in both Nucella and Trophon consists of two aragonitic layers and an outer layer of calcite. Specimens of both may lack the inner- most (transverse) layer (Figs. 28, 37). More detailed stud- ies may reveal the cause of this variation. Perhaps en- vironmental factors may play a role (Etter, personal communication).

Character 8: The morphology of the bursa copulatrix of Nucella is very similar to that of Trophon. In both taxa, a relatively small, muscular blind sack branches off from the vagina (Figs. 47, 48). In Ocenebra the bursa is thin- walled and equal in width and height to the capsule gland, extending for up to V2 the length of the pallial complex. The ventral channel loops backwards towards the anterior portion of the bursa in Ocenebra (Fig. 53), rather than straight up into the bursa as in Trophon and Nucella (Fig. 47).

The above two characters could be considered synapo- morphies for an alternative, but less parsimonious, tree in which Trophon and Nucella would be united in one clade. However, in the proposed phylogenetic hypothesis (Fig. 65), four synapomorphies support a clade consisting of Nucella and Ocenebra. rendering the above two char- acters as homoplastic.

Fretter and Graham (1962) mention several similari- ties in egg capsule morphology between Nucella lapillus and Ocenebra erinacea. Both species lay vase-shaped capsules, whereas Trophon geversianus produces dis- coidal egg capsules. However, having discoidal egg cap- sules is only an autapomorphic trait for Trophon and does not provide clues about relationship in this case. Alternative, equally parsimonious transformation series are possible for characters 3, 4, 5, and 8. For Characters 3, 5, and 8, I chose the scenario involving homoplasy over one involving a reversal to avoid an "artificial" increase in synapomorphies. Similarly, for Character 4, I chose the least linear trans-formation series ("zero state" evolving into both the "three state" and the "one state").

Zoogeographical data reveal that members of Nucella, Ocenebra and Trophon occur primarily in colder waters of the temperate and boreal zones, whereas rapanines and the outgroup occur primarily in warmer waters of the (sub)tropics (Kool, 1989).

Nucella lapillus and Ocenebra erinacea overlap for much of their ranges in primarily temperate western European waters. In addition, N. lapillus occurs in the

western Atlantic, where O. erinacea does not, and O. erinacea occurs in the Mediterranean, where N. lapillus has not occurred since the Pleistocene [Malatesta (1960) cited records of N. lapillus from the Pleistocene of Sicily]. Cooke (1915), in a comprehensive list of localities for Nucella lapillus, showed that the southernmost record for this species is the Algarve coast of Portugal and al- leged that any records from Northern Africa (see Nord- sieck, 1982), the western Mediterranean, the Azores, and the Canary Islands, are highly suspect. Other members of what can be assumed to be Ocenebra s.s. and Nucella s.s. are found in the eastern Pacific (Abbott, 1974) and the northern I'acific. Furthermore, Ocenebra s.s. occurs in western Africa (Houart, 1989) and South Africa (Kil- burn & Rippey, 1982). Ranges of these genera may be revised when more Ocenebra-like taxa (for example from Japan) and Nucclla-Uke species have been examined with respect to their anatomy, radula, shell ultrastructure, etc. Such studies are also necessary to determine if, for ex- ample, species such as Nucella dubia and Nucella squa- mosa, both from the South African Province, are indeed members of Nucella s.s. It appears from preliminary dissections that the genus Nucella can no longer be con- sidered restricted to the temperate waters of the northern hemisphere (Kool, in preparation).

Trophon geversianus, limited to the South American continent, lives in temperate to boreal waters, as do Nu- cella lapillus and Ocenebra erinacea.

SYSTEMATIC CONCLUSIONS

The high degree of similarity in anatomy, radula, pro- toconch, shell ultrastructure and operculum in Ocenebra erinacea, Trophon geversianus and Nucella lapillus in- dicates that these three taxa are more closely related to one another than any one of them is to Thais or other representatives of Rapaninae. Nucella should therefore be excluded from Rapaninae to maintain monophyly (Kool, 1989; 1993, in press). The difficulty of correctly allocating Nucella to a subfamily is indicative of the dilemma of our lack of understanding of higher muri- coidean systematics. The cladistic analysis and the re- sulting cladogram (Fig. 65) suggest that Nucella is better placed in Ocenebrinae than in Trophoninae. It is obvious that the boundaries of groups at the higher taxonomic categories, traditionally based on shell characters, be- come less clear after completion of thorough anatomical studies of members from different genera and subfam- ilies. Results shown here suggest that Trophon geversi- anus, the type species of Trophoninae, is closely related to Nucella and Ocenebra. Perhaps it is more closelv related to the latter two taxa than to other species hitherto included in Trophoninae. It is beyond the scope of this paper to suggest synonymization of Trophoninae with Ocenebrinae. However, I suspect that future studies will show that Trophoninae is not a monophyletic group and that a new name for some of its members may be war- ranted. The following systematic arrangement is pro- posed for the taxa treated herein:

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THE NAUTILUS, Vol. 107, No. 2

MURICOIDEA Rafinesque, 1815

MURICIDAE Rafinesque, 1815

RAPANTNAE Gray, 1853 (sen.su Kool, 1993, in press)

Thais Roding, 1798 OCENEBRINAE Cossmann, 1903

Ocenebra Gray, 1847

Nucella R6ding, 1798 TROPHONINAE Cossmann, 1903)

Trophon Montfort, 1810

ACKNOWLEDGEMENTS

I thank Drs. Richard S. Houbrick, M. G. Harasevvych, and Kenneth J. Boss for reviewing an early draft of this manuscript. I thank the staff of the Scanning Electron Microscope Laboratories at the United States National Museum of Natural History and the Smithsonian Marine Station at Link Port, Ft. Pierce, for their assistance. Dis- cussions with Dr. Diana Lipscomb were of great help in fine-tuning the section on the cladistic analysis. Dr. An- ders Waren kindly sent me some well-preserved material of Ocenebra erinacea; Dr. James H. McLean and Mr. C. Clifton Coney provided specimens of Trophon gev- ersianiis. This is Contribution No. 333 of the Smithsonian Marine Station at Link Port, Ft. Pierce, Florida.

LITERATURE CITED

Abbott, R T, 1974, American Seashells, 2nd edition. \'an Nostrand Reinhold Company. New York, 663 pp.

Agersborg, H. P. K. 1929. Factors in the evolution of the prosobranchiate mollusc Thais lapillus. The Nautilus 43(2): 45-49.

Ankel, W. E. 1937. Der feinere Bau ties Kokons der Purpur- schnecke Nucella lapillus (L I und seine Bedeutung tiir das Laichleben, V'erhandkingen der Deutsclien Zoologischen Geselischaft Supplement 1077-86

Bandel, K. 1975. Das Embryonalgehiiuse mariner Prosobran- chier der Region von Banyuls-sur-Mer I. Teil. Vie et Milieu 25(1 Kser. A):83-118.

Bandel, K. 1977. Neogastropod radulae from Ban\uls-sur- Mer. Vie et Milieu, 27(2)(ser. A): 191-232

Bryan, G. W., Gibbs, P. E., Hummerstone, L. G,, and Burt, G R. 1986 The decline of the gastropod Nucella lapillus around South-West England: evidence for the effect of tributyltin from antifouling paints Journal of the Marine Biological Association of the L'nited Kingdom 66:61 1-640.

Carriker, M, R. 1981. Shell penetration and feeding by na- ticaceaii and muricacean pretlatory gastropods: a synthe- sis. Malacologia 20(2):403-422,

Colton, H S 1922. Variation in the dogwhelk Thais (Purpura auct.) lapillus Ecology 3:146-157.

Gonnell, J H 1970. A predator-pre\ system in the marine intertidai region. 1. lialanus glamlula and several pred- atory species of Thais. Ecological Monographs 40:49-78

Cooke, A. H. 1915. The geographical distribution of Purjjura lapillus (L.). Part I: in palaearctic waters. Proceedings of the Malacological Society of London ll(4):192-209

Cossmann, A. E. M 1903. Essais de Paleoconchologie Coiii- paree. Vol. 5. Paris, 215 pp.

Oothers, J. H. 1973. On variation in Nucella la])illus (L.): shell shape in populations from I'cmbrokcshirc, Soulli

Wales. Proceedings of the Malacological Societv of London

40:318-327. Crothers, J. H. 1983. \ ariation in dog-whelk shells in relation

to wave action and crab predation. Biological Journal of

the Linnean Society 2085- 102 Crothers, J. H. 1985. Dog-whelks: an introduction to the bi- ology of Nucella lapillus Field Studies 6:291-360. D'Asaro, C. N. 1991. GunnarThorsons world-wide collection

of prosobranch egg capsules: Muricidae. Ophelia ■351):1-

101. Emien, J. M. 1966. Time, energy, and risk in two species of

carnivorous gastropod. Ph.D. dissertation. University of

Washington, Seattle, Washington. Etter, R. J. 1987. The effect of wave action on the biology

of the intertidai snail Nucella lapillus PhD dissertation.

Harvard University, Cambridge, Massachusetts, i-ix + 198

PP

Feral. C 1976 Repartition geographique des femelles a trac- tus genital male externe chez Ocenebra erinacea (L.), es- pece gonochorique. Haliotis 7:29-30

Fretter V. and ,\. Graham. 1962. British Prosobranch Mol- luscs. Ray Society, London, 755 pp

Fretter V. and .\ tJraham. 1985. The prosobranch molluscs of Britain and Detmiark. Part 8 - Neogastropoda Journal of Molluscan Studies, Supplement 15:435-556.

Gmelin, J. F. 1791. /n; Linnaeus, Svstema Naturae, Tom 1, Pars \'l. pp. 3021-3909

Graham, A. 1941. The oesophagus of the stenoglossan pro- sobranchs. Proceedings of the Ro\ al Societ\ of Edinburgh 61(l)(sec B):l-23.

Graham, A. 1955. Molluscan diets Proceedings of the Mal- acological Society of London 31(3-4):144-159.

Gray, J. E. 1847. A list of the genera of Recent Mollusca, their synonyma and t\ pes Proceedings of the Zoological Society of London 15:129-219.

Gray, J E. 1853. On the division of ctenobranchous gaster- opodous Mollusca into larger groups and families.The .■\n- nals and Magazine of Natural History 11 (Ser,2):124-133.

Harasewych, M. G. 1984 C^omparati ve anatom\ of four prim- itive muricacean gastropods: implications for trophonine phylogeny. American Malacological Bulletin 3(1): 11-26.

Haw kins, L. E. 1985. Ecoph\siological studies of the Euro- pean o\ster drill Ocenclna crii^acca (Linnaeus, 1758). Ph.D. dissertation, L'niversit\ of Southampton, England, 244 pp.

Houart, R 1989 Description of a new species of Ocenebra (Muricidae: Ocenebrinae) from western .\frica Publica- 9oes Ocasionais da Sociedade Portuguesa de Malacologia No. 13, pp. 63-64.

Jeffreys, J. G. 1867. British Conchology, X'olume 4. \'an Voorst, Paternoster Row, London, 486 pp., 8 pis.

Jousseaume, F. 1888. Descriptions des mollusques recueilles par M. leDr Faurotdansla Mer Rouge etdu Golfed .\den. Memoires de la Societe Zoologique de F" ranee 112-223.

Kilbnrn, H. and E. Rippe\. 1982. Sea Shells of Southern .Af- rica South C:hina Printing Co , Hong Kong. 249 pp

Kincaid, T. 1957. Local races and clines in the marine gas- tropod Thais lamellosa Gmelin. .^ population study. Cal- liosloma Co., Seattle, Washington, 75 pp , 65 pis.

Kool, S I' 1986. Systematic revision of tliaulid genera based on anatomy, .\merican Malacological Bulletin 4:110.

Kool, S P 1987 Significance ol raihilar characters in recon- struction of thaidid ph>logeny (Neogastropoda:Murica- cea). The Nautilu.s 101 l3l: 117-132.

Kool, S I' 1988. Aspects of the anatonn ol Vluopurpiira

S. p. Kool, 1993

Page 57

patula (Prosobranchia: Muricoidea: Thaidinae), new com- bination, with emphasis on the reproductive s\steni. Malacologia 29i2);37.3-382.

Kool, S. P. 1989, Ph\ logeneticanal>sis of the suhlamii\ Thai- dinae (Prosobranchia: Neogastropoda; Muritidae) Ph D Dissertation, The George Washington I niversit\, Wash- ington, DC. 3-42 pp.

Kool, S. P. and K. J. Boss. 1992. Sucella K.kling, 1798 (CJas- tropoda: Muricidae): tvpe species. The Nautilus 106(1): 21-23.

Kool, S. P. 1993. Phylogenetic analysis of the Rapaninae (Neo- gastropoda: Muricidae). Malacologia (in press).

Lamy, E. 1928. La ponte chez les gasteropodes prdsohraiiches. Journal de Conch) liologie 72(2)80-148

Largen, M. J. 1967. The diet of (lie dog-wliclk, Succlla la- pillua (Gastropoda Prosobranchia), Journal ot Zoology 151: 123-127.

Lebour, M. \'. 1937. Tlie eggs and larvae ol the lirilish pro- sobranchs with special reference to those living in the plankton. Journal of the Marine Biological .'\ssociation of the United Kingdom 22:105-166,

Linnaeus, C. 175S. Systema Naturae, 10th ed, Stockhohn, 824

PP

Malatesta, .•\ 1960 Malacofauna Pleistocenica di Grammi- chele Memorie per Servire alia Descrizione della Carta Geologica d Italia 121-392, 19 pis, v\ith letter press,

Melvill, C. and R, Standen. 1898. Notes on a collection of marine shells from Livelv Island, Falklands, v\ith list of species. Journal of Conchology 9(4):97-105.

Montfort, D. de. 1810. Conchy liologie Svstematique, et Clas- sification Methodique des Coquilles. Part 2, Paris, 676 pp.

Moore, H, B, 1936. The biology of Purpura lapilliis. I, Shell variation in relation to environment Journal of the Marine Biological Association, of the United Kingdom 21:61-89,

Moore, H,'^B, 1938, The biology of Nucclla lapillm. Ill Life history and relation to environmental factors. Journal of the Marine Biological Association of the L'nited Kingdom 23:67-74,

Murdoch, W, W, 1969. Switching in general predators: ex- periments on predator specificity and stability of prey populations. Ecological Monographs 39:335-354,

Nordsieck, F 1982 Die Europaischen Meeres-Gehiiuse- schnecken (Prosobranchia), Fischer Verlag, Stuttgart, 539 PP

Oehlmann, J , E. Stroben and P, Fioroni, 1988, Zur .Anatomie und Histologic des Fortpflanzungssystems von Nucella la- pillus (L., 1758) (Prosobranchia, Stenoglossa). Zoologische Anzeiger 221(3/4):101-116.

Pallas, P. S. 1774. Spicilegia Zoologica, Vol 1, Part 10 Lange, Berolini, 41 pp., 4 pis.

Palmer, R I 1983. Growth rate as a measure ot food value in thaidid gastropods: assumptions and implications for prev morphology and distribution. Journal of Experimen- tal and Marine Biology and Ecology 7395-124

Palmer, R. I. 1985. .Adaptive value of shell variation in Thais lamctlosa. effect of thick shells on vulnerabilitv to and preference bv' crabs. The X'eliger 27(4):349-356,

Pelseneer, P, 1911, Recherches sur I embryologie des gastro- podes, Memoires de I'.^cademie ro\ ale de Belgique, Classe des sciences 3(2):1-167,

Rafinesque, C. S. 1815. Analyses de la nature ou tableau du univers et des corps organises. Barravecchia, Palermo, pp. 5-6. 136-149, 218-223.

Risbec, J 1937. Les irregularites et les anomalies du devel- oppement emlirv oiuiaire chez Murex e'rinacetis L. et chez Purpura lapillus L. Bulletin du Laboratoire Maritime de Dinard 17:25-38,

Robertson, R, 1974, Marine prosobranch gastropods. Larval studies and svstematics, Thalassia Jugoslavica 10(1/2):213- 238.

Roding, P. F 1798 Museum Boltenianum. Part 1, Hamburg, 156 pp.; Part 2. Hamburg, i-viii + 199 pp.

Sabelli, B. and S. Tommasini. 1987. Osservazioni sulla radula e sulla protoconca di Ocenchra crinaceus (L.,1758) e Had- riana orctca (Vokes, 1964), Bolletino Malacologico 23(9- 10):275-283,

Schumacher, C, F, 1817, Essay dun Nouveau Systeme des Habitations des Vers Testaces, Copenhagen, 287 pp,

Sowerby, G. B. 1841. Conchological Illustrations, Part II. Murex. A catalogue of recent species 9 pp. -I- Index, pp. 1-22.

Spight, T. M. 1972 Patternsof change in adjacent populations of an intertidal snail, Thais lamcUosa. PhD dissertation, Universitv of Washington, Seattle, Washington, 325 pp.

Spight, T. M. 1976, Colors and patterns of an intertidal snail, Thais lamellosa. Researches on Population Ecology 17: 176-190

Spight, T M, 1982 Population sizes of two marine snails with a changing food suppl> Journal of Experimental Marine Biology and Ecology 57:195-217,

Thorson, G 1941. Marine Gastropoda Prosobranchiata The Zoology of Iceland 4(60): 1-150.

Thorson, G 1946 Reproduction and larval development of

Danish Marine Bottom Invertebrates Meddelelser

fra Kommissionen for Danmarks Fiskeri- og Havunder- sogelser Serie: Plankton 4:1-523

Wenz, W. 1941. Prosobranchia. In: Handbuch der Palao- zoologie. Volume 6. OH. Schindewolf, ed., Gebriider Borntraeger, Berlin, part 5, pp. 961-1200.

THE NAUTILUS 107(2):58-62, 1993

Page 58

Thala esperanza, a new Costellariidae (Mollusca: Gastropoda) from northern Puerto Rico

Jose H. Leal' Donald R. Moore

Rosenstiel School of Marine am! Atmospheric Science Uni\ersity ol Miami 4600 Rickenbacker