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Dr. Chong CHEN

Dr. Chong CHEN

Deep-sea biologist. Malacologist. Evolutionary biologist. "Mollusc collector", photographer.

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The C. Chen Collection: “Kogkhulion”

“Kogkhulion” (Greek: “Conch”) is a photographic reference to world molluscs using specimens from the C. Chen Collection; continually updated. Mouse-hover over an image will display the scientific name, clicking/tapping reveals the full image with a detailed species account. For a searchable version, click here.

Lepetodrilus disco Gu, Chen, Zhou & Sun, 2026 <br /> LEPETODRILIDAE<br /> Holotype (RSIO 72GAS001); <br /> -3350 m, Tianxiu vent field (60°11'E, 6°22'N), Carlsberg Ridge, By manipulator of HOV Jiaolong (dive JL213), R/V Shenhaiyihao cruise DY72, 2022/vi/03, 5.7 mm <br /> <br /> Known from several deep-sea hydrothermal vent fields in the central and northern Indian Ocean ranging between 2600~3350 m deep, Lepetodrilus disco is a lepetodrilid limpet with a smooth, low shell with the apex positioned just anterior of the shell edge. The shell shape is oval, narrowing more anteriorly than posteriorly. A little-varied species, only some minor variations among the known specimens have been recognised, especially in the shell shape. <br /> <br /> It inhabits surfaces of 'chimney' deposits formed by the hydrothermal vent fluids reacting with cold seawater, and is a common species in its natural habitat. Nevertheless, as it is restricted to several very small vent fields smaller than soccer fields it can only be collected with research submersibles and is therefore known from just a small series of specimens. Though the specific feeding ecology is not known for this species, other members of the genus Lepetodrilus are known to combine grazing on bacterial films and filter-feeding using the gill, and this species may do the same. Typical shell length around 5 mm, though very large specimens can attain 10 mm. <br /> <br /> A few congeners such as the L. schrolli Beck, 1993 from Manus Basin vents in the southwestern Pacific share a similar shell morphology with L. disco, but the radular characters of L. disco differs in having inner lateral teeth with a protruded, semicircular outer part and the middle lateral teeth lacking clear serrations on the inner edge. The specific epithet 'disco' refers to its flat and oval, disc-like shell shape.
Eupleura pectinata (Hinds, 1844)<br /> MURICIDAE<br /> -60~80 m, Dredged, Gulf of Chiriqui, Panama, 2002, 35.1 mm <br /> <br /> Ranging from Baja California, Mexico to the Pacific side of Panama, Eupleura pectinata is a highly distinctive muricid characterised by two thick, spinous, fan-like varices per whorl combined with a long anterior siphonal canal. Inhabiting sand and mud bottoms of subtidal waters around 50~300 m deep, it is a carnivorous and predatory gastropod feeding on other invertebrate animals. It is a rather rare species only occasionally taken as a by-catch from shrimper nets. A little-varied species, only minor variations are seen in the length and direction of the spines. In adults typically there are five to six spines on each varix. It has also been found as fossils that extend back at least to the Early Pliocene and possibly Late Miocene. Typical shell length around 40 mm, very large specimens may reach 60 mm. <br /> <br /> Although several species in the genus Eupleura also exhibit two varices per whorl, no other species has such an elongate, constricted siphonal canal that makes E. pectinata morphologically unique and easily recognisable among the living congeners. It is most similar to the Middle to Late Miocene fossil species E. thompsoni Woodring, 1959 which is a possible precursor species, although E. thompsoni has stronger intervarical nodes, a smaller aperture, and less regularly spaced varices. As having two varices in each whorl is a rarely seen feature among muricids, Eupleura species have been historically confused with Bursidae and Ranellidae. This species is no exception -- as it was originally named as Ranella pectinata Hinds, 1844. The specific epithet 'pectinata' means 'comb-like' in Latin, referring to the varices carrying numerous spines and resembling a comb.
Provanna cocytus Chen, Watanabe & Kawagucci, 2026<br /> PROVANNIDAE<br /> Holotype (NSMT-Mo 79870), 6.3 mm;<br /> -3086 m, Cold seep on the northwestern slope of the Okushiri Ridge (44°14.2064'N, 139°6.0480'E), By suction sampler, HOV Shinkai 6500 dive #1873 (2025/viii/30), R/V Yokosuka cruise YK25-14C, Northeastern Sea of Japan, Japan. <br /> <br /> Only known from deep-sea cold seep environments in the northeastern Sea of Japan ranging between 2679-3349 m in depth, Provanna cocytus is a provannid snail characterised by a thin, translucent shell with strongly inflated whorls and constricted suture while lacking in significant sculpture. The name 'cocytus' refers to the ninth and final Circle of Hell in Dante Alighieri's 'Divine Comedy", depicted as a vast and remorseless frozen lake. This is because its habitat in the bottom layer of the Japan Sea Proper Water is very cold at only around 0.3°C, the coldest environment known across all deep-sea abyssochrysoidean snails. <br /> <br /> Although rather abundant in its natural habitat, it is currently restricted to three cold seep sites and can only be collected by research submersibles. Like other Provanna species, it is thought to be a grazer feeding on the bacterial mat in the cold seep. These bacteria are capable of using the chemical energy from the oxidation of reducing substances in the seep geofluid such as methane to make sugar, and are therefore abundant at such habitats. A little-varied species, the only significant variation seen across specimens is that some specimens can exhibit a number of very weak spiral cords. Typical shell length around 5 mm, the largest known specimen is 7.5 mm in shell length. <br /> <br /> The thin, inflated shell lacking a clearly defined siphonal notch differentiates it from other similar smooth-shelled Provanna such as P. laevis Warén & Ponder, 1991 from seeps on both sides of the Pacific and P. lucida Sasaki, Ogura, Watanabe & Fujikura, 2016 from Okinawa Trough hydrothermal vents. Furthermore, its radula is unique in having a blunt and truncated central tooth cusp and a lateral tooth where the 3rd or 4th cusp is the strongest, plus entirely lacking in an angular buttress.
Plectostoma mirabile (Smith, 1893)<br /> DIPLOMMATINIDAE<br /> On limestone, Gomantong Hill, Sandakan, Sabah, Malaysia, Borneo Island, 5.0 mm <br /> <br /> Perhaps the most famous among all diplommatinid snails in the genus Plectostoma known for their irregular coiling and intricate ornamentation, Plectostoma mirabile is an endemic species of Sabah, Malaysia on the northern Borneo Island. Only known from limestone outcrops in the Gomantong Hill in Sandakan Division of Sabah home to an intricate network of limestone caves known as Gomantong Caves, it is restricted to an area of about 1.2 km2 -- exemplar of the extremely narrow ranges seen in many limestone-specialist landsnails. <br /> <br /> As the name suggests, it has a 'miraculous' shell sculpture that is one of the most extreme of the genus, comprising dense axial lamellae that are drawn out to form broad, open spines. The coiling in the earlier whorls is regular, but in the adult body whorl the axis is shifted abruptly and the coiling direction reverses to form a 'snaking' tuba leading up to the aperture with a strongly expanded apertural shield. The formation of tuba in Plectostoma has been found to be an effective defence against predators like slugs in the genus Atopos and firefly larvae which prefers to attack the snails from the aperture, and the dense spines and varices are thought to further enhance the snail's protection against such predators. The shell is thin and translucent, the whorls themselves carry a golden hue while the spines are white. Generally, it is a little-varied species except slight variability in the spine development, and is instantly recognisable from its characteristic shell shape and ornamentation. Typical shell width around 4 mm, the largest specimens may approach 6 mm. Originally it was placed in the genus Opisthostoma as O. mirabile, and it is still much better known under that name. <br /> <br /> Although locally common in its natural habitat, its restricted distribution means it is a species highly threatened by habitat loss. Limestone quarrying already caused its local extinctions at two small outcrops, leading it to be assessed as Critically Endangered in the IUCN (International Union for Conservation of Nature) Red List.
Spinosipella deshayesiana (Fischer, 1862)<br /> VERTICORDIIDAE<br /> -200 m, Trawled, Off Punta Engaño, Mactan Island, Central Visayas, Philippines, 11.4 mm <br /> <br /> A small verticordiid bivalve with a very fine and delicate sculpture consisting of numerous radial ribs that carry dense scales leading to a prickly appearance, Spinosipella deshayesiana is widely distributed in the Indo-West Pacific where it ranges from Mozambique to India to Japan to Australia. An uncommon species, it inhabits soft bottoms of shallow to moderate depths between about 50~200 m deep. Verticordiids are thought to be carnivorous and feed by capturing small crustaceans such as copepods using mucus-lined tentacles, and S. deshayesiana likely does the same. The shell form is a little variable leading to slightly different height to width ratio in each valve, although the prickly varices mean it is always instantly recognisable. The internal surface of the valves is nacreous and brightly pearly in appearance. Typical shell length around 10 mm, very large specimens can exceed 15 mm. <br /> <br /> It was named in honour of the French geologist and malacologist Gérard Paul Deshayes (1795-1875), who was a professor at the Muséum National d'Histoire Naturelle, Paris. In Japan it has a delightful and fitting vernacular name, "Uzumaki-Gokoro" which means the "Vortex Heart". This species is often confused with the very rare congener Spinosipella costeminens (Poutiers, 1981) which also has an Indo-West Pacific distribution, but S. costeminens differs by having much stronger, blade-like varices that lack the delicate scales. Furthermore, S. conteminens is a much larger species with an average shell length around 20 mm and the largest specimens reaching 30 mm.
Hirtomurex winckworthi (Fulton, 1930)<br /> MURICIDAE<br /> -150 m, By tangle net, Aliguay Island, Zamboanga del Norte, Philippines, 32.2 mm <br /> <br /> The "Winckworth's Latiaxis" is a coralliophiline snail characterised by a shell with spiral ribs bearing dense, delicate scales crossing with axial ribs carrying open spines to form a latticed sculputure. The development of axial ribs and length of spines vary greatly among individuals, as well as the number of ribs per whorl. The spire height and length of the anterior siphonal canal are also somewhat variable, but most specimens are approximately equal in shell height and width. The shoulder is usually angulated, but some individuals exhibit a rounded shoulder. The umbilicus is always wide open and deep. <br /> <br /> A rarely seen species, it is a carnivorous gastropod that feeds on corals on which it is an ectoparasite of, as is typical for members of the subfamily Coralliophilinae. It has a very wide distribution range across the Indo-West Pacific from South Africa all the way to Japan, where it inhabits moderate depths between about 100~400 m deep. Many specimens used to originate from coral nets in Japan when the precious coral industry was lively in the late 20th Century, but now most specimens come from the Philippines and are taken by deep-water tangle nets. Typical shell length is around 30 mm, but very large specimens can exceed even 50 mm. <br /> <br /> It is most similar to the congener Hirtomurex teramachii (Kuroda, 1959) which has a similar distribution range, but the two can be separated morphologically in that H. teramachii lacks significant axial sculpture and never exhibits open spines. It was named after the British natural historian and malacologist Ronald Winckworth (1884-1950) who worked at the Royal Society and also served as the president of the Conchological Society of Great Britain and Ireland.
Ferreiraella populi Sigwart in SOSA [Senckenberg Ocean Species Alliance] et al., 2026<br /> FERREIRAELLIDAE<br /> -5506 m, On sunken wood on the abyssal plain near the Izu-Ogasawara Trench off Japan (32°34.6760'N, 143°46.1235'E), Collected by a suction sampler mounted on HOV Shinkai 6500, R/V Yokosuka, 22.1 mm <br /> <br /> Only known from a single sunken wood site on the northwestern Pacific abyssal plain off Japan, Ferreiraella populi is a ferreiraellid chiton characterised by an unusually small tail plate. At 5506 m deep, this sunken wood is currently the world's deepest known natural wood fall (i.e. not artificially deployed for scientific research), and this species is one of the most dominant animals there. All chitons from the family Ferreiraellidae are endemic to sunken wood, they are thought to be secondary consumers that do not directly digest wood and instead rely on gut symbionts that do -- but how exactly members of the genus Ferreiraella obtains nutrition from wood remains unclear. It is currently known from just a handful of specimens collected by a deep-diving manned submersible. <br /> <br /> The aesthetes of F. populi has fewer pores in each bundle where the macrasthetes and micraesthetes are separated by greater distance that typical for the genus. The radula is also diagnostic as the comb-form major uncinus 'sweeper' teeth typical of the genus is much smaller than other known species. These characters, combined with the small tail valve, distinguish F. populi from all other known congeners. Typical body length around 15 mm, very large specimens can attain 25 mm. Like many other species of the genus, the tail valve is often colonised by serpulid tube worms.<br /> <br /> The specific epithet 'populi' means 'of the people', and was the outcome of a public naming competition on YouTube in collaboratio with the internet performance artist and YouTuber Hosea Jan "Ze" Frank, an initiative intended to raise awareness of taxonomy and enhance public engagement with species discovery. This name was sugggest independently 11 times from over 8000 total contributions to the public naming competition.
Curvemysella paula (Adams, 1856)<br /> LASAEIDAE<br /> Attached to siphonal canal of a Bufonaria rana (Linnaeus, 1758) shell occupied by a hermit crab, Inami Port, Hidaka, Wakayama Prefecture, Japan, 1991/ii/10, 9.6 mm <br /> <br /> A crescent-shaped galeommatoidean bivalve with a unique life style, Curvemysella paula lives exclusively attached by byssus to the columellar interspace in the siphonal canal of gastropod shells occupied by hermit crabs such as Diogenes goniochirus Forest, 1956. It is a filter-feeding bivalve that benefits from this relationship by having better access to food, since the host hermit crab generates feeding and respiratory currents that aids the bivalve's filter-feeding. The anterior end of the bivalve is always pointed towards the umbilical opening on the gastropod shell, in order to filter-feed efficiently. Furthermore, the bivalve also likely enjoys protection from predators by living in a difficult to access confined space in the gastropod shell. The hermit crab is not known to gain anything from this relationship, but it also pays little cost. As such, C. paula is thought to be in obligatory commensalism with the hermit crab host. <br /> <br /> A broadly distributed species across the Indo-West Pacific, the type locality is Torres Strait of Australia but it has been recorded from localities such as Japan, Aden in the Red Sea, Vietnam, and Queensland, Australia. It can be found in intertidal waters down to about 100 m deep and is a common species in its habitat, a study in Japan found over 60% of herbit crab shells being occupied by C. paula. The shell is inequivalve with the right shell being much larger than the left, the shell shape is always curved and twisted but the extent is greatly variable depending on the shape of the columellar, as it is able to shift the shell shape to match the available space. The curvature increase with growth, juveniles are much more equivalve in appearance. Typical shell length around 10 mm, very large specimens may reach 15 mm. Due to both its unusual morphology and habitat, it cannot be confused with any other bivalve species.
Pseudomalaxis zanclaeus (Philippi, 1844)<br /> ARCHITECTONICIDAE<br /> -240 m, Dredged, Canopus Bank, 193 km (120 mi) off Fortaleza, Ceará, Brazil, 2005/xi, 4.5 mm <br /> <br /> A flat, coin-like and almost planispiral shell fringed by two strong peripheral keels characterises the "Noble Sundial", a small architectonicid snail with a very broad distribution across the Atlantic and Indo-West Pacific. In the Atlantic, it ranges from Virginia, U.S.A. to Brazil to western Africa and into the central Mediterranean Sea. In the Indo-West Pacific the range extends from southern Japan to northern New Zealand to South Africa. The Indo-West Pacific populations are typically treated as a distinct subspecies P. z. meridionalis (Hedley, 1903) from the nominal Atlantic subspecies due to the geographic separation, although the two are virtually identical morphologically except a typicall smaller protoconch in the nominal subspecies. Even this character is overlapping (0.8-1.0 mm vs 0.9-1.1 mm) and genetic data is sought to test whether the two truly deserve separation. <br /> <br /> Both subspecies are extremely rare across their very broad ranges, and are much sought-after by collectors. It has been recorded from a rather wide bathymetric range between about 20~400 m on mud, sand, gravel, and coralligenous bottoms. The diet is unknown but it is likely a carnivorous snail feeding on cnidarians as is typical for arachitectonicids. A little-varied species, most variations seen involves the strength of peripheral keels and the number of minor spiral striae formed between the two keels. The shell colour ranges from white to light yellowish brown. Typical shell length around 10 mm, very large specimens can exceed 15 mm. <br /> <br /> Pseudomalaxis nobilis (Verrill, 1885) is a well-known junior synonym for the nominal subspecies, while P. solaris Kuroda, 1938 is a junior synonym of the Indo-West Pacific subspecies proposed based on the population from Japan. The most similar species is the Indo-West Pacific congener P. obolos (Barnard, 1963), which differs by having a spiral rib on the shoulder slope set apart from the peripheral keel, and by having weak spiral ribs between the basal keel and the umbilicus which is never seen in P. zanclaeus.
Babelomurex fruticosus (Kosuge, 1979)<br /> MURICIDAE<br /> -100~200 m, By tangle net, Off Samal, Davao del Norte, Philippines, 2025/v, 24.4 mm <br /> <br /> Two rows of long spines that carry numerous scales leading to a branching appearance characterises the "Bushy Latiaxis", a stunning coralliophiline snail ranging from the Philippines to southern Japan in the western Pacific. Like other members of subfamily Coralliophilinae it feeds on the body fluid of corals and is an external parasite. A moderately common species, it lives on host corals in moderate depths between about 100~300 m deep. Specimens from the Philippines are typically taken by tangle nets, while those from Japan are usually by-catches from coral nets and deep-water dredges. <br /> <br /> A quite variable species in terms of shell height and spine development, but it is always easily recognisable from the scaly spines that differentiate it from similar congeners such as B. spinosus (Hirase, 1908). The spines are directed posteriorly in vast majority of specimens, but they can sometimes also be directed anteriorly. The scales on the spines can also vary in size and frequency. As the spine morphology is better seen from the apex view, this species is easier to identify from that view. The shell surface is whitish and typically carry sparse patches of reddish brown, although some specimens are all-white. Typical shell length around 20 mm, very large specimens can exceed 30 mm.
Clavus canalicularis (Röding, 1798)<br /> DRILLIIDAE<br /> -20 m, Dived, Labuan Bajo, Lesse Sunda Islands, Indonesia, 2025/viii, 18.3 mm <br /> <br /> The "Ear Turrid" is a spectacular drilliid snail characterised by a row of strong shoulder elements that are often drawn out to form open, scale-like spines. A common species widely distributed in the western Pacific, it ranges from Japan to the Philippines to New Caledonia. Inhabiting sand and gravel bottoms of shallow waters from extreme low tide down to about 20 m deep, it is a carnivorous and predatory gastropod feeding on other invertebrate animals, as is typical for drilliids. <br /> <br /> A very variable species, the shoulder sculptures can range in strength from small, sharp tubercles to extensive, wing-like spines. Most specimens are bi-coloured, with a whitish background and an orange to dark reddish brown colour band anterior of the shoulder; but some specimens lack this colour band and are all white. Sometimes the colour band is present but very pale. Furthermore, the shell height-to-width ratio is also very variable, and specimens can range from elongate to stout forms even when not taking the spines into account. <br /> <br /> There are several congeners in the Indo-West Pacific that are morphologically similar and sometimes confused with it, such as C. rugizonatus Hervier, 1896 and C. devexistriatus Kilburn, Fedosov & Kantor, 2014. Among these species, C. canalicularis is the only one where the shoulder elements can form long, open spines. The short-spined forms of C. canalicularis can also be differentiated from other species in lacking spirally alinged nodules or widely set spiral striae on the shell base. Typical shell length around 20 mm, very large specimens can attain 30 mm.
Lunovula superstes (Dolin, 1991)<br /> OVULIDAE<br /> -433~450 m, Dredged on coral rubble, Stylaster Bank (23 37.80'S, 167 42.70'E), New Caledonia, Leg. Felix Lorenz, 8.8 mm <br /> <br /> An elegantly pyriform shell with a white to pinkish dorsum encircled by an orange to reddish brown ring characterises Lunovula superstes, a small ovulid with a broad distribution range in the Indo-West Pacific where it has been found in New Caledonia (type locality), Japan, the Philippines, and Réunion. It is an uncommon species across its range, but due to its small size it is difficult to sample and thus rarely seen in collections. Like other ovulids it feeds on benthic cnidarian colonies, specifically it lives on deep-water stylasterids between about 100~800 m deep and is an external parasite. <br /> <br /> The original description considered it to be a relict species of the extinct Cenozoic genus Cypraeopsis, but this was later shown to be inaccurate as all Cypraeopsis species had cowrie-like shells with smooth dorsum. Instead, it is now placed in the extant genus Lunovula. It is a very little-varied species that only exhibit minor differences in how dark the colour ring is and in the height to width ratio -- but always easily recognisable. In many specimens the outer lip is slightly rolled, likely due to the attachment condition to the host stylasterid. The combination of a relatively elongate shell with a fine reticulate sculpure and the reddish brown ring separates it from all other known Lunovula species. Typical shell length around 8 mm, very large specimens may exceed 12 mm. Lunovula venusta Tsuchida & Kurozumi, 1999 described from Japan is a junior synonym.
Favartia pelepili D'Attilio & Bertsch, 1980<br /> MURICIDAE<br /> -100~200 m, By tangle net, Off Talikud Island, Samal, Davao del Norte, Philippines, 2025/v, 30.2 mm <br /> <br /> Characterised by densely branching spines that cover the entire shell, the "Pelepili Dwarf Murex" is a strikingly ornamented muricid ranging between the Philippines and central Japan. Inhabiting hard substrates of moderate depths between about 50~200 m deep, it is a carnivorous and predatory gastropod feeding on other invertebrate animals. <br /> <br /> Though it is often confused with other western Pacific congeners such as F. judithae D'Attilio & Bertsch, 1980 and F. maculata (Reeve, 1845), it is actually easily distinguished by the distal tips of the major spines which always splits into several smaller spines in a 'star-burst' fashion -- a feature missing in other similar species. It is variable in other aspects of the spine development such as spine lengths and curvature, and also how recurved the siphonal canal is. Specimens from the Philippines tend to possess longer spines than those from Japan. Individuals can also vary somewhat in colouration from light reddish brown to dark brown, though it does not exhibit the more striking colour morphs of some other congeners like bright yellow or orange. <br /> <br /> An uncommon species, it is quite a challenge to obtain a showy specimen with long, intact spines. Typical shell length around 25 mm, very large specimens may attain 35 mm. The name 'pelepili' is a combination of Pele, the Hawaiian goddess of volcanoes, and 'pili' which means 'hairs' in Latin, and is a reference to the dense and finely split spines that resemble thin, hair-like strands of volcanic glass.
Dentifusus deynzeri Vermeij & Rosenberg, 2003<br /> FASCIOLARIIDAE<br /> -200~300 m, Dredged, Off Aliguay Island, Philippines, 68.4 mm <br /> <br /> The "Toothed Spindle" is a unique fasciolariid characterised by a well-developed labral tooth in adults combined with strong and regular spiral cords. The labral tooth is thought to have evolved independently in this species, one of five lineages with independently evolved labral tooth in the family Fasciolariidae. There is no closely related species that share similar features, and thus a new monotypic genus was established to house it at the time of discovery. Inhabiting sandy bottoms of moderate depths between about 100~300 m deep, it has only been found in the southern Philippines with most specimens coming from off Aliguay Island, Balut Island, or Davao, and is thought to be an endemic species there. <br /> <br /> A very rare species known from no more than a few dozen specimens, most of which are empty shells, not much is known about its ecology. Nevertheless, the well-developed labral tooth indicates it probably is a carnivorous gastropod and an active predator of bivalves. A little-varied species, the only notable difference in shell morphology among the known specimens is the colouration where the intervarical space can range from whitish to pale tan to dark caramel brown. The labral tooth is only developed in adults and is lacking in juveniles. Typical shell length around 60 mm, very large specimens may exceed 75 mm. <br /> <br /> The specific epithet honours Albert E. "Al" Deynzer (1936-2022), a shell collector and dealer based in Sanibel, Florida, U.S.A., who donated the type material for scientific study. The genus name Dentifusus is literally a combination of the Latin words for tooth ('dens') and spindle ('fusus').
Boreoscala greenlandica (Perry, 1811)<br /> EPITONIIDAE<br /> -200 m, Trawled, Bering Sea, Off Russia, 1995, 37.8 mm <br /> <br /> Characterised by broad, pure white axial lamellae laced over a high-spired shell, the "Greenland Wentletrap" is a cold-water epitoniid with a circum-Arctic distribution and is known from the northern Pacific northwards of Honshu, Japan, the northern Atlantic north of New York, U.S.A., and the Arctic Ocean. Most specimens originate from deep-water trawl bycatches around Sea of Okhotsk and Bering Sea. It has a broad bathymetric range from extreme low tide to about 650 m, where it is found on soft bottoms. Like other epitoniids, it is a parasitic species that feed by sucking the body fluid of cnidarians, particularly sea anemones. <br /> <br /> The shell is rather variable among individuals, in terms of the shell height to width ratio and the development of the axial varices. Both the breadth of each varix and the frequency on each whorl can differ greatly among individuals. In some specimens the varices are flattened, while in others they are more upright and blade-like. The spiral sculpture consists of several deep grooves that run throughout the entire teleoconch, which are overlaid by the axial varices. The shell background colour of the early whorls tend to be yellowish in adults, while the later whorls are bluish white. Typical shell length is around 30 mm, but very large specimens can exceed even 60 mm. It is an uncommon species throughout its range, though large and intact specimens are quite scarce. <br /> <br /> Due to its large variability, it has quite a few form names and junior synonyms such as B. planicosta (Kiener, 1838), B. subulata (Couthouy, 1838), B. major (Kobelt, 1888), and B. angustior Kobelt, 1888, to list a few. A notable form is f. norvegicum (Clench & Turner, 1952) described from off Norway, which carries more numerous axial varices than the typical form. Its shell morphology is unusual among epitoniids and is rarely confused with other species, though B. matugisiense (Ozaki, 1958) is a rather similar species. These two species can be distinguished by B. matugisiense having much denser and narrower axial varices, and reaching a much larger size (typical shell length around 60 mm, very large specimens can exceed 100 mm).
Prototyphis eos (Hutton, 1873)<br /> MURICIDAE<br /> Lowtide under rock, Matai Bay, North Island, New Zealand, Leg. Douglas Snook, 1976/i, 14.6 mm <br /> <br /> The "Dawn Murex" is a delicately sculptured muricid endemic to the northern New Zeland, characterised by a shell with three sharply raised wing-like varices per whorl which carry a distinct pattern where bands of dark reddish brown alternate with the background colour. The shell background colour is very bright pink when alive, but rapidly fades to light orange or yellow after death. A carnivorous and predatory gastropod feeding on other invertebrate animals, it inhabits shallow waters from very low tide down to subtidal waters of about 30 m deep in shingle beaches where it lives under and among cobbles. Beached shells are not uncommon, although the shell is so fragile that these tend to be worn with no colour left. Live specimens are quite rarely seen, usually collected under cobbles during extreme low tide. Typical shell length around 20 mm, very large specimens can exceed 30 mm. <br /> <br /> The form P. eos f. paupereques (Powell, 1974) differs from the typical form by having longer and straighter shoulder spines, giving the shell a wider appearance. It was originally described as a separte species from off Poor Knights Islands, but has since been also collected in the northern part of North Island. Some authors have treated it as a subspecies but as its range overlaps with the typical form it is best treated as a form, unless evidence can be presented to separate it again as a distinct species. The specific epithet 'eos' refers to Eos, the rosy-fingered goddess of dawn in Greek mythology, and likely refers to its bright pink colouration when alive. <br /> <br /> It is most similar to the congener P. angasi (Crosse, 1863) from southeastern to southwestern Australia, which is most easily separated by lacking the characteristic banded colouration of P. eos. These two species have been confused in the past and often treated as one species as they look extremely similar when worn or faded, with the subspecies P. angasi powelli (Fleming, 1962) once named based on fossil material from New Zealand but now treated as a synonym of P. eos.
Flexopteron poppei (Houart, 1993)<br /> MURICIDAE<br /> -300 m, By tangle net, Off Langab, Balut Island, Davao Occidental, Philippines, 2004, 29.8 mm <br /> <br /> Elegantly ornamented with 8-10 highly raised, blade-like axial lamellae, the "Poppe's Murex" is a truly stunning muricid endemic to the Philippines. A very rare species that inhabits rather deep waters between about 300~500 m depth, all known specimens have been taken by tangle nets around Balut Island. The feeding ecology remains entirely unknown, but it is assumed to be a carnivorous and predatory snail feeding on other invertebrate animals as is typical for Muricidae. It is a little-varied species, the main differences among specimens is the shell colouration which can vary from white to light tan to bright orange, and the development of the blade-like varices can also differ somewhat. Typical shell length around 40 mm, very large specimens can reach 55 mm. The umbilicus is closed in young specimens, but the offset in the position of every new anterior siphonal canal increases with growth so that in large adult shells a narrow umbilicus is formed. <br /> <br /> Since its description, its beauty and rarity has captivated many shell collectors and it is now one of the most sought-after muricid species. Unfortunately the blade-like varices are extremely delicate and prone to breakage both naturally and during collecting even with tangle nets. As a result, it is extremely difficult to obtain a specimen with most varices intact and displaying the characteristics of the species well. Many specimens offered as intact have been manipulated by 'shell doctors' who would manually repair the varices in great detail and fill holes on the shell using resin so the shell sells for a higher price. In some cases, almost the entire shell is fake and is actually merely a resin cast. This is among the most frequently faked high-profile species in the Philippines and shell collectors are advised to examine the shells very carefully using black light (most resin mixtures would brightly fluorescent under black light) and acetone solution (which would rapidly dissolve resin but has no impact on the real calcium carbonate shell material) before making a purchase. <br /> <br /> Originally this species was described in genus Poirieria, as Flexopteron was treated as its subgenus at the time. Later, some authors also treated it as a Paziella. Ultimately, Flexopteron was separated out as a genus in its own right, including F. poppei. It was named after the Belgian conchologist and shell dealer Guido T. Poppe, best known for running the shell company Conchology, Inc. based in the Philippines. Poppe provided the first two known specimens for scientific study, leading to its formal description. It is a highly distinctive and instantly recognisable species especially when the varinces are intact -- it is the only living Flexopteron species lacking the formation of inner denticles on the mature outer lip and also the only living species where the axial lamellae are not crossed by major spiral cords.
Naquetia confusa Houart, Moe & Chen, 2025<br /> MURICIDAE<br /> -5~6 m, Dived, Balabac Island, Palawan, Philippines, 36.8 mm <br /> <br /> For a few decades, the muricid snail Naquetia vokesae (Houart, 1986) was thought to have a wide but disjunct distribution range in the Indo-West Pacific, with one part in the western Indian Ocean between Tanzania and Mozambique and another in the Pacific located in the Palawan Provice of the Philippines. The Pacific population appeared to be endemic to Palawan and has never been collected elsewhere in the Philippines despite considerable collecting efforts. Recently, after close examination of the shell morphology using numerous specimens from both parts of the distribution, minor but consistent conchological differences were found which supports the hypothesis that Indian and Pacific ocean populations actually represent two separate species. As the type locality of N. vokesae was in northern Mozambique, the Palawan species needed a new name and was described as Naquetia confusa -- the name reflecting the history of confusion with N. vokesae. <br /> <br /> The two species are very similar but exhibit the following consistent differences: 1) N. confusa has more rounded teleoconch whorls with shorter, narrower siphonal canal than N. vokesae; 2) N. confusa has spiral cords that are further apart from each other than N. vokesae; 3) intervarical ribs of N. confusa carry stronger beads of more consistent strength than N. vokesae even in the adult body whorl, beading is usually diminished in the adult whorl of N. vokesae; 4) the ventral sculpture on the apertural varix is finer and more scabrous in N. confusa than N. vokesae; and 5) N. confusa is much smaller (typical shell length around 35 mm, very large specimens reaching 50 mm) compared to N. vokesae (typical shell length around 50 mm, very large specimens may approach 90 mm). <br /> <br /> Another very similar species is N. triqueter (Born, 1778) which has a continuous and wide distribution approximately ranging between Indian and Polynesia, but N. triqueter has a conical protoconch of 3.5 whorls indicative of planktotrophic development rather than the pausispiral protoconch of 1.5~2 whorls seen in N. vokesae and N. confusa that indicates lecithotrophic dispersal. <br /> <br /> Naquetia confusa is a little-varied species, although the extent of the dark brown colour patches can vary among individuals. It is apparently a moderately common species locally in Palawan, with most specimens known being collected from shallow waters off the Balabac Island between 5~30 m deep.
Coluzea rosadoi Bozzetti, 2006<br /> COLUMBARIIDAE<br /> -330~360 m, Trawled, Off Mafia Island, Pwani Region, Tanzania, 29.3 mm <br /> <br /> Native to waters off Tanzania and Mozambique in East Africa, the "Rosado's Pagoda" is a small columbariid snail with a heavily sculptured shell characterised by a deep subsutural ramp and a row of long, outward-projecting spines on the shoulder. Known specimens have all been trawled or dredged from soft bottoms of rather deep waters between 300~600 depth, it is a very rare species probably due to this confined distribution and inaccessible habitat. It appears to be a little-varied species overall, and specimens vary mostly in the development and length of the shoulder spines which number about 10~12 per whorl. Typical shell length around 35 mm, very large specimens may reach 45 mm. It was named after the mozambican conchologist José Rosado, who collected and donated the type material for study. <br /> <br /> Among other Coluzea species in this region it is most similar to C. groschi Harasewych & Fraussen, 2001 which also carry similar shoulder spines, but C. groschi lacks the subsutural ramp entirely and the spiral cords are also much weaker than C. rosadoi. The shell colouration of C. groschi is usually a light yellowish brown, as opposed to the pure white shell of C. rosadoi. Coluzea juliae Harasewych, 1989 and C. eastwoodae (Kilburn, 1971) also carry shoulder spines but they are short and blunt triangular spines and not the long, sharp spines seen in C. rosadoi. Both C. juliae and C. eastwoodae are also much larger, averaging around 70 mm and reaching a maximum size of about 90 mm.
Eumitra suduirauti Bozzetti, 1997<br /> MITRIDAE<br /> -300 m, By tangle net, Tinina, Balut Island, Mindanao, Philippines, 2024/x, 47.1 mm <br /> <br /> An all-white shell characterised by a deep and wide subsutural ramp on the shoulder, the "Suduiraut's Mitre" is a strange species whose classification has been mysterious and much debated. In the original description it was only tentatively placed in genus Eumitra with teleoconch sculpture and columellar plicae cited as the reasoning, but the author noted the large size and the small protoconch with a sharply pointed spire deviated from typical members of the genus. Furthermore, the wide aperture and raised subsutural ramp are both morphological features rarely seen in the entire family Mitridae.<br /> <br /> The superficial conchological similarity has even led to some authors and shell dealers to place it in the volutid genus Lyria as Lyria suduirauti, a name that has once spread across the collectors but has no scientific support. Nevertheless, the generic and familial placement of this species remains unclear and radula morphology and/or molecular data are much sought to clarify its position; it may indeed be an unusual mitrid or it could prove to belong to a separate family like Volutomitridae. In the mean time, it remains in genus Eumitra. <br /> <br /> An endemic species of the Philippines with most specimens coming from around either Balut Island or Aliguay Island, it is a very rare species inhabiting rather deep waters between 200~500 m depth and is usually taken by tangle nets. Nothing is known about its feeding ecology, although it is a neogastropod and thus probably a carnivorous and predatory gastropod feeding on other invertebrates. It is a little-varied species and is always instantly recognisable. Typical shell length around 40 mm, very large specimens may approach 55 mm. <br /> <br /> It was named in honour of Emmanuel "Manou" Guillot de Suduiraut (1938-2010), a French conchologist and shell dealer who spent the later half of his life in the Philippines whose favourite families were Mitridae and Costellariidae. Suduiraut's investment in tangle netting as a source of deep-water molluscs resulted in many species new to science at the time, a number of which was named after him.
Parilimya loveni (Jeffreys, 1882)<br /> PARILIMYIDAE<br /> -120 m, Trawled on mud bottom, Off Capraia, Tuscan Archipelagp, Italy, 1983, 35.2 mm <br /> <br /> The "Lovén's Parilimya" is an anomalodesmatan bivalve in Parilimyidae with an inflated, wedge-shaped shell carrying around 30 fine radial ribs. The shell is strongly inequivalve with the apperance of one valve enveloping the other; the valves are covered by fine tubercles, and they are semi-transparent at the thinnest parts. In adult shells the beaks of the two valves come into contact with each other, and in many specimens the beaks are damaged due to this. <br /> <br /> First discovered by the British survey ship HMS Porcupine, it is now known have a distribution range from the northeastern Atlantic around the Azores to the Mediterranean Sea. Living buried in soft substrates, it apparently has a very broad bathymetric range from continental slope into abyssal depths, between 100~2200 m deep. The feeding ecology of Parilimyidae is not well-understood as no direct observation has been made, though anatomical evidence such as the presence of a long, wide-mouthed inhalant siphon typically used for prey capture and a stomach architecture typical of carnivorous species suggest they are likely predatory bivalves feeding on small invertebrate animals. A rare species partly due to its habitat depth, intact specimens are very scarce due to the valves being very thin and fragile. Typical shell length around 30 mm, very large specimens may come close to 40 mm. <br /> <br /> Originally described in the genus Pholadomya and later moved to Parilimya, today these two genera are placed in two different families (Pholadomyidae and Parilimyidae, respectively), the only two extant families in the superfamily Pholadomyoidea. This species was named after the eminent Swedish marine biologist Sven Ludvig Lovén (1809-1895) who was the director of invertebrate biology at the Swedish Museum of Natural History.
Cymbiola distructa Zheng & Maxwell, 2025<br /> VOLUTIDAE<br /> -110 m, Trawled, Timor Sea, 103.6 mm <br /> <br /> For several decades, a population of volutids in the genus Cymbiola with spinous spire found in the neighbouring Arafura and Timor Seas have been known to shell collectors through specimens taken as prawn trawl by-catches reaching private collections. These shells were first thought to represent unusual populations of either C. cymbiola (Gmelin, 1791) or C. scottjordani Poppe and Tagaro, 2005 after that species was named; since these two species occurred in Indonesia and therefore appeared plausible geographically. However, the shell morphology of these Arafura and Timor specimens differed from C. cymbiola in being much larger with an average shell length of about 100 mm and the largest specimens approaching 120 mm (vs. average of about 65 mm and maximum of 90 mm for C. cymbiola), the protoconch being much larger and flatter, and that the spines are shorter and become more attenuated on the adult body whorl. On the other hand, C. scottjordani is similar in size but has a much more brightly pigmented shell and lacked spines entirely on the spire. <br /> <br /> Finally in 2025, the Arafura and Timor specimens were named as a separate species -- Cymbiola distructa. The specific epithet "distructa" refers to the broken, or destructed, state of most of the available specimens due to damages from trawls. It has always been a scarce species and with no fresh material surfacing for many years now, it is now very rare. Nothing is known about its ecology, but it is most likely a carnivorous and predatory gastropod inhabiting sandy bottoms like other congeners; most specimens have been taken from moderate depths between 100~200 m deep. All known specimens so far are light cream in colour and patterned with four spiral bands of fine brownish peppery dots. This consistent colouration is unlike that of the sister species C. cymbiola, which is more variable with some shells being chocolate-brown in colour.
Chaetoderma naga Liu, Chen, Gu & Sun, 2025<br /> CHAETODERMATIDAE<br /> -1385 m, Taken using a push-core from black anoxic sediment, Haima cold seep (16°43.937'N, 110°27.681'E), South China Sea, ROV Pioneer, R/V Xiangyanghong 01 cruise XYH01-2022-06, 2022/ix/20. <br /> Center: Holotype (SCSMBC240201), 131.0 mm; Bottom left: Paratype 1(SCSMBC240202), 81.0 mm; Top right: Paratype 2 (SCSMBC240203), 29.1 mm. <br /> <br /> With an average body length around 100 mm and a maximum known body length of 131 mm, Chaetoderma naga is the world's third largest caudofoveate worm-mollusc -- after C. shenloong Chen, Liu, Gu, Qiu & Sun, 2024 at 154 mm and C. felderi (Ivanov & Scheltema, 2007) reaching 365 mm. So far C. naga has only been collected from deep within black anoxic sediment at Haima cold seep site, South China Sea at 1385 m deep. Although it seems to be common in its natural habitat, it is difficult to collect due to its complete burial in sediment that renders it invisible from the surface. As such, only a few specimens have been sampled to date. Fully adult individuals tend to have the spicules stained in dark mud leading to a dark grey colour, but young individuals lacking the mud stain are beige. Due to its large, snake-like body form, this species was named after Nāga, a group of serpent-like deities appearing in many Asian mythologies. <br /> <br /> At Haima it co-occurs with the sister species C. shenloong, the two species share a very similar gross external morphology and are difficult to identify in the field. However, the two species differ significantly in the arrangement and size of calcareous spicules. For example, the simple, needle-like spicules can be over 1 mm in C. shenloong but they are less than one-third of that in C. naga. The two species share an isoceles-triangle shaped spicules, but the region where this spicule type occurs also differ between the them (in C. naga they can be found in the posterior part of the body but not in C. shenloong). Like C. shenloong, C. naga also likely hosts bacterial symbionts capable of chemosynthesis primary production inside its body and rely on them for energy. <br /> <br /> (Original photos by Xu Liu, Composite image and text by Chong Chen)
Veprichlamys incantata (Hertlein, 1972)<br /> PECTINIDAE<br /> -200 m, Dredged, Off Santa Cruz Island, Galápagos Islands, Ecuador, 1972/x, 42.5 mm <br /> <br /> With a very restricted known distribution off Santa Cruz Island, the "Charming Scallop" is a pectinid endemic to the Galápagos Islands. The shell is whitish to pinkish white, very thin and fragile. The valves carry dense, scaly radial ribs about 25 in number that carry numerous sharp, reddish spines; three to five minor ribs are typically present in the interspaces between the major ribs. A filter-feeding bivalve inhabiting moderately deep waters between about 100~200 m depth, it is considered a very rare species. However, this may be biased by the fact that most sampling in the Galápagos have occured at diving depths and not in the deeper waters this species occurs in. <br /> <br /> Typical shell length around 40 mm, very large specimens may approach 60 mm. It is a little-varied species except slight differences in the number of ribs and the development of scaly spines, and is always easily recognisable. The presence of numerous secondary ribs on both adult and juvenile shells (over about 10 mm) sets it apart from all known living Veprichlamys species. Its probable ancestors were widely distributed in the southeastern Pacific in the Miocene and the most similar species in the fossil record is Veprichlamys onzola (Olsson, 1964)† of the Pliocene Ecuador, meaning the endemism of this lineage in the Galápagos seen today is likely the result of a rather recent range reduction.
Pyropelta artemis Chen, Tsuda & Watanabe, 2025<br /> PYROPELTIDAE<br /> Holotype (NSMT-Mo 79628)<br /> -910 m, Off Hatsushima hydrocarbon seep, Sagami Bay (35°0.9405'N, 139°13.3901'E), Taken by suction sampler mounted on HOV Shinkai 6500 on-board R/V Yokosuka, 4.1 mm<br /> <br /> A pyropeltid limpet only known from the Off Hatsushima hydrocarbon seep in Sagami Bay, Japan, Pyropelta artemis is notable for its phenotypical plasticity in shell shape. It occurs on a wide range of habitat types such as tubes of annelid worms and mussel and snail shells. The shell 'shape-shifts' according to shape of the substrate, resulting in strongly curved shells when living on tubeworms and flat shells when living on mussels. The specimen shown was chosen as the holotype, due to having intermediate shell shape between the two extremes. <br /> <br /> It feeds on bacterial mats growing on these surfaces by grazing using its radula. As is typical with Pyropelta species, its shell surface is usually corroded to reveal concentric rings corresponding to layers in the shell microstructure. Although a common species in its natural habitat, due to the restricted distribution it can only be sampled by research submersibles and is therefore a rarely collected species. Typical shell length around 3 mm, very large specimens can reach 5 mm. <br /> <br /> All Pyropelta species are very similar and challenging to distinguish morphologically, but a combination of shell outline shape when on a flat surface, shell microstructure, and radula characters separate it from all other described congeners. The most similar species is Pyropelta yamato Sasaki, Okutani & Fujikura, 2003 also from Japan, but they differ in radula morphology where the cusps of the innermost three lateral teeth are equal in size in P. yamato but in P. artemis the innermost lateral has a much-reduced cusp. The specific epithet refers to Artemis, goddess of moon and the hunt in the Greek mythology, likening the shifting shell shape of P. artemis to the waxing and waning of the moon.
Reticutriton lineatus (Broderip, 1833)<br /> CYMATIIDAE<br /> -10~20 m, Dived on rocky bottom, Fernandina Island, Galápagos Islands, Ecuador, 60.3 mm <br /> <br /> Numerous equally-spaced, dark reddish brown spiral lines gives the "Lined Hairy Triton" its name, and makes it a distinctive species among cymatiids. An endemic species of the Galápagos Islands, Ecuador, it is a carnivorous and predatory gastropod feeding on invertebrate animals and inhabits rocky bottoms of subtidal waters between around 10~50 m depth. Its range covers the entire the Galápagos Islands, with records from Isla Isabela to Isla Genovesa to Isla Española to Isla de San Cristóbal. Due to its restricted distribution in the highly protected Galápagos Islands, it is a very rarely seen species in collections. It is a little-varied species, though the strength of intervarical nodes which can differ considerably among individuals. The chitinous operculum is much smaller than the aperture. Typical shell length around 60 mm, very large specimens can reach 85 mm. <br /> <br /> Originally described in the genus Triton, it was then transferred to Cymatium as Cymatium lineatum for many years before being moved to Reticutriton. It is one of only two species in the genus Reticutriton, the other being Reticutriton pfeifferianus (Reeve, 1844) which is very broadly distributed across the Indo-West Pacific. As R. pfeifferianus lacks the spiral lines that characterises R. lineatus and also has a much longer anterior siphonal canal, the two species are very easily separated.
Conus armiger Crosse, 1858<br /> CONIDAE<br /> -80 m, Trawled by fishing boat, Gulf of Mexico, Off Pensacola, Florida, U.S.A., 1970's, 39.6 mm <br /> <br /> The aptly named "Mace Cone" is characterised by a pyriform shell resembling a spiky mace, with an elongate anterior extension and the whole surface densely dorned by numerous low and sharp nodes. An endemic species of the Gulf of Mexico where it has been found around the entire continental shelf from Florida, U.S.A. to Yucatán, Mexico. A carnivorous and predatory gastropod feeding on annelid worms, it inhabits a rather wide bathymetric range around 50~600 m deep and mostly on soft and gravel bottoms. A very rarely seen species in collections, this may partly be due to its range largely overlapping with the extensive oil rigs and pipes in the Gulf of Mexico resulting in its habitat being difficult to access and collect. <br /> <br /> Usually an instantly recognisable species but the shell shape is somewhat variable and some specimens have less protruded shoulders and sometimes the anterior part is shorter than usual, resulting in a more stout impression. Typically the shell surface is densely covered with reddish brown dots that mostly align with the nodes, but some specimens lack this pattern and appear almost completely white. Typical shell length around 30 mm, very large specimens are known to exceed 40 mm. Conus frisbeyae Clench & Pulley, 1952 is a junior synonym, and C. clarki Rehder & Abbott, 1951 is another; the latter was a name given to the whitish form without the reddish brown dots. <br /> <br /> For many years it has been placed in the subgenus (or genus) Conasprella, but more recently it has been moved to Dalliconus which is a geographically more sensible allocation. Conus bajanensis Nowell-Usticke, 1968 is a more southernly distributed sister-species that occurs off the southeastern Caribbean to the northern South America around Trinidad and Tobago to French Guiana. The two species differ in that C. bajanensis has a generally broader shell with less numerous shoulder nodes and never carries the reddish brown dots typical of C. armiger; although some unusually short specimens of white C. armiger can be sometimes difficult to separate from C. bajanensis.
Distorsionella lewisi (Beu, 1978)<br /> THALASSOCYONIDAE<br /> -300~400 m, By tangle net, Tinina, Balut Island, Mindanao, Philippines, 2024/ix, 54.3 mm <br /> <br /> The "Lewis' Distorsio" is a thalassocyonid snail native to the southern Pacific, characterised by a cancellate sculpture and a weakly toothed aperture on both the inner and outer lips. First described from New Zealand where it was collected from the southern Norfolk Ridge and Kermadec Islands, it was later also discovered off New Caledonia, Vanuatu, and the Philippines. A deep-water species found between 150~650 m deep, it is quite rare in the shallower part of its bathymetric range and most specimens have been collected by scientific research cruises from depths beyond 500 m where it becomes locally uncommon. Nevertheless, this very deep habitat means it is very challenging to collect and therefore a rarely seen species in collections. The shell is covered by a pale yellowish brown, finely bristled periostracum when alive. Typical shell length around 35 mm, very large specimens as shown can approach 55 mm. <br /> <br /> When first named it was placed in Distorsio (now Personidae) due to the overall similarities in shell form and a strongly toothed aperture, although Distorsionella was established at the same time as a subgenus to house this species due to it having a reticulate protoconch sculture and weaker aperture dentitions overall. Distorsionella was later raised to a full genus when the only other congener Distorsionella pseudaphera Beu, 1998 was named from New Caledonia. The two species of Distorsionella are easily distinguished, as D. lewisi is much larger than D. pseudaphera (average shell length around 10 mm, very large specimens may exceed 15 mm) and also has more denticles on both the inner and outer lips. It was named in honour of Harold Lewis (1927-1988), a graphic designer and amateur conchologist who focussed on tonnoidean gastropods, especially Cymatiidae and its allies. <br /> <br /> Recently, a molecular phylogeny surprisingly revealed that Distorsionella is infact more closely related to the enigmatic genus Thalassocyon (once considered to be a member of Ficidae) than other personids like Distorsio. As a result, it was moved with Thalassocyon into a new family: Thalassocyonidae. This result indicates the unusual shell morphology of Thalassocyon was secondarily modified from a more personid-like ancestor. Unlike superficially similar personids in genera Distorsio and Personopsis, the outer lip of D. lewisi carries several denticles of roughly equal size rather than one or two being obviously enlarged. The aperture of D. lewisi is also less constricted by denticles and the inner lip is much less flared; the spire is also not as distorted in the coiling axis as is typically seen in personids.
Scabrotrophon bondarevi (Houart, 1995)<br /> MURICIDAE<br /> -125 m, Dredged on gravel and clay, Sea of Okhotsk, Onekotan Island (49°37.0'N, 154°44.1'E), Kurile Islands, Leg. Evgeniy A. Kozlov, 2017/i/14, 51.7 mm <br /> <br /> A delicate and elegant muricid characterised by strongly raised, blade-like lamellose varices, the "Bondarev's Trophon" is endemic to the northern Kurile Islands and the vast majority of specimens have been collected off either Paramushir Island or Onekotan Island. A carnivorous and predatory gastropod feeding on marine invertebrates and especially bivalve molluscs, it typically inhabits Chlamys scallop beds on muddy sand and gravel at moderate depths between 100~350 m deep. Although locally only uncommon, the remote distribution makes it rarely seen in collections. The shell is very fragile and typically heavily damaged by the dredging or trawling process, making intact specimens very scarce. <br /> <br /> The shell form is rather variable especially with regards to the development and number of varices, which can vary from as few as seven to as many as 13 per whorl. In some individuals the varices are narrow giving an impression of a slender shell, whereas in other individuals they are very wide; sometimes short, broad spines are produced as part of the varices near the shoulder. Fine spiral striae are present throughout the body whorl, but their strength also differ greatly among individuals. Typical shell length around 50 mm, very large specimens exceed 60 mm. <br /> <br /> Initially it was placed in the genus Nipponotrophon, later it was moved to Scabrotrophon based on shell sculpture and also the position of nucleus on the operculum (situated in the apical left of a teardrop-shaped operculum for Nipponotrophon and apical center of an ovate operculum in Scabrotrophon). This species was named in honour of Dr Igor P. Bondarev who donated the holotype specimen for study; Bondarev was a biologist working at the A. O. Kovalevsky Institute of Biology of the Southern Seas and also an avid shell collector.
Arctomelon tamikoae (Kosuge, 1970)<br /> VOLUTIDAE<br /> -350~400 m, Trawled, East off Buldir Island, Aleutian Islands, Alaska, U.S.A., 1997/vii, 165.5 mm <br /> <br /> An exquisite cold-water volutid combining a dark purplish brown aperture and numerous raised axial ribs, the "Tamiko's Volute" is endemic to the central and western Aleutian Islands in Alaska, U.S.A. from the south of Yunaska Island to the west of Attu Island. In the original description the type locality was given as East China Sea, but this is clearly erroneous as this species has never been found outside the Aleutian Islands. Since this species was named from a single holotype discovered in a personal collection in Japan, there was most likely a misplacement of data labels and records leading to an inaccurate locality data. <br /> <br /> For over two decades since its naming it was only known from the holotype, until in 1994 the conchologist Roger N. Clark who regularly participated in fisheries resource assessment surveys in the Aleutians rediscovered this species and its actual locality by collecting two specimens. An exceedingly rare species, according to the published record of Clark only less than 20 specimens have been taken in over 3000 survey trawls carried out off the Aleutian Islands. <br /> <br /> Although generally little-varied, there is some variability in the strength of axial ribs. Typically, the axial ribs are strongest on the early teleoconch whorls, becoming increasingly obsolete in the adult body whorl and almost completely dissapearing by the last one-third. In gerontic specimens the early whorls tend to be flattened by erosion, resulting in a truncated spire. Typical shell length around 150 mm, extremely large individuals can exceed even 200 mm. <br /> <br /> This species was named in honour of Mrs. Tamiko Oh-ishi of Nagasaki, Japan, the shell collector who owned and donated the first known specimen (the holotype) to the National Museum of Science and Nature in Japan for its description. It is easily distinguished from all other congeners such as A. stearnsii (Dall, 1872) as it is the only species with axial ribs.
Leptotrophon inaequalis Houart, 1995<br /> MURICIDAE<br /> -400 m, Dredged, Southwest of Île des Pins (Isle of Pines), New Caledonia, Leg. Vincent Crayssac, 18.2 mm <br /> <br /> Characterised by a strongly angulate and posterior-projecting shape of the outer lip resulting in a strongly angulate teleoconch whorls, Leptotrophon inaequalis is an unusual deep-water muricid endemic to the southern New Caledonia. Dredged between about 350~450 m deep, it is a rare species mostly known from empty shells. Although the exact diet is unknown, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals like other muricids. <br /> <br /> The strong axial varices each carry two small spines of which only one is above the suture, the development of these spines differ in strength among individuals. Otherwise it is a little-varied species except the height to width ratio that can differ somewhat. The protoconch is tall, 1.5 whorls, and carries a single spiral keel. Typical shell length around 15 mm, very large specimens can reach 20 mm. <br /> <br /> One of many intricately sculptured Leptotrophon species inhabiting deep water habitats around New Caledonia, its angulate aperture shape is unique among all known species and is thus instantly recognisable. It is known to co-occur side by side with the congener L. acerapex (Houart, 1986), which lacks the angulate aperture and carries three spines per varix.
Bacula morisyuichiroi (Habe, 1968)<br /> EULIMIDAE<br /> -5 m, Dived on sand, Onna-son, Okinawa Island, Japan, 2019/viii, 3.1 mm <br /> <br /> A unique eulimid snail with a glassy and strongly recurved shell carrying strongly expanded peripheral keels, Bacula morisyuichiroi inhabits sandy habitats of shallow waters down to about 20 m depth. Like all eulimids it is presumably a parasite of echinoderms, but to date no information has become available on its host species. The genus Bacula has similar shell morphology to Pyramidelloides species whose hosts are ophiuroids, and has been suggested to most likely also be parasitic on ophiuroids. <br /> <br /> It was originally described from Amami Oshima in southern Japan, and now it has also been found in several other localities across the western Pacific such as Taiwan and French Polynesia. A rather rarely seen species, almost all specimens known to date have been found as empty shells recovered from shell grit. Typical shell length around 3 mm, very large specimens may exceed 5 mm. <br /> <br /> Though a very distinct and easily recognised species, there can be some variations in strength of the peripheral keel and spire curvature among individuals. In fresh specimens the protoconch carries a brown tinge. It is most similar in shell morphology to the congener B. kajiyamai (Habe, 1961) which has a similar distribution from Japan to New Caledonia, but they are easily separable as B. kajiyamai has a weaker peripheral keel as well as a straight spire instead of a curved one like B. morisyuichiroi.
Bathylepeta wadatsumi Chen, Tsuda & Ishitani, 2025<br /> LEPETIDAE<br /> Holotype (NSMT-Mo 79627)<br /> -5922 m, On shelf-like volcanic rock on the western escarpment of a graben structure in the northwestern Pacific (32°37.0617'N, 144°6.5835'E), 500 km southeast of Tokyo, Japan, Taken by a suction sampler on HOV Shinkai 6500, 40.5 mm <br /> <br /> Discovered from almost 6 km deep, the "Wadatsumi Limpet" is the world's deepest known patellogastropod limpet. Inhabiting volcanic rock surfaces on a complex, raised graben structure in the northwestern Pacific off Japan, only a single specimen was collected (the holotype) although a few more were sighted in the region. As it lives on a rather steep rocky wall in great depths where deployment of dredge or trawl gear is extremely challenging, its collection required the use of a scientific submersible which is the only type of equipment capable of sampling from such habitats. From the feeding trails seen on the rocks, it is clearly grazing on the sediment layer on these rocks which observation of the gut also confirmed as it was filled with grey-brown muddy sediment. <br /> <br /> The only known specimen is 40.5 mm in shell length, which is a gigantic size for a gastropod living in such depths and not relying on chemosynthetic symbiosis at hot vents or cold seeps. Its name was taken from both the god of sea Wadatsumi in the Japanese mythology, and also the giant pirate fish-man "Large Monk" Wadatsumi character from the Japanese manga series ONE PIECE (1997~) by Eiichiro Oda. <br /> <br /> The shell is characterised by numerous white, radial rays on the shell collectively resembling a 'star-burst' pattern. Although the congener B. linseae Schwabe, 2006 from the Weddell Sea in Antarctica also possesses a similar shell pattern, the two species differ clearly in the radular characters where B. wadatsumi has well-developed instead of reduced second lateral and marginal teeth, as well as having an imbricating instead of non-overlapping basal plates. Previously, the congener Bathylepeta laevis Moskalev, 1977 from 5300–5320 m deep off Chile was the deepest Patellogastropoda, a record broken by B. wadatsumi. This is also the first time a Bathylepeta species was found in the northern hemisphere, suggesting a much broader distribution of these giant abyssal limpets in the global deep sea.
Lyria poppei Bail, 2002<br /> VOLUTIDAE<br /> -400 m, Dredged, Off Norfolk Ridge, New Caledonia, 2000's, 31.2 mm <br /> <br /> The "Poppe's Lyria" is a small volutid endemic to Norfolk Ridge in New Caledonia, characterised by a shell sculptured with rounded axial ribs and patterned by three spiral bands of orange to reddish brown blotches overlaid by narrow spiral lines. Found between 200~500 m deep, most specimens known have been dredged from hard bottoms. Due to its restricted habitat in rather deep waters, it has always been a rather rare species. Although the specific diet is unknown for this species, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals as is typical for the family. In living individuals a corneous operculum is present, much smaller in size than the aperture. Typical shell length around 35 mm, very large specimens can approach 50 mm. <br /> <br /> Individuals are highly consistent in shell form but vary considerably in pattern development, especially in the strength of dark spiral lines. The specimen shown is the typical form which exhibits two spiral regions free of any patterning, while the other form has equally-spaced dark spiral lines overlaying the entire shell. The lattern form is very similar to Lyria kuniene Bouchet, 1979, although in L. kuniene the spiral lines are only present on the raised axial ribs and lacking in the intervarical spaces. Furthermore, in L. kuniene the early whorls are much narrower with a more elevated protoconch. Lyria kuniene is also a larger species with an average shell length of around 50 mm that can reach even 80 mm; large specimens of L. kuniene have a strongly angled shoulder that is lacking in L. poppei. Although L. kuniene is also a New Caledonian species, it is typically dredged from Isle of Pines and the two species do not overlap in range. <br /> <br /> Lyria poppei was named in honour of the Belgian conchologist Guido Poppe who runs the well-known company Conchology, Inc. based in the Philippines in addition to his numerous contributions to the discovery and description of new species of molluscs.
Leptochiton cascadiensis Sigwart & Chen, 2017<br /> LEPTOCHITONIDAE<br /> -1 m (-3.1 ft.) tide at low intertidal, Under rock, Ripple Island, San Juan Islands, Washington, U.S.A., Leg. H. Scheidt, Ex-coll. Tom Rice, 4.8 mm<br /> <br /> Part of the morphologically very similar Leptochiton rugatus (Carpenter in Pilsbry, 1892) complex, the "Cascadia Chiton" ranges between the panhandle of Alaska through Pacific coast of Canada to Oregon, U.S.A. Inhabiting rocky surfaces of intertidal and shallow subtidal depths down to at least about 10 m deep, it is a grazer feeding presumably on algae and other material, although the exact feeding preferences are unknown. There are deeper records that supposedly refer to this species, these remain unconfirmed. Typical shell length around 5 mm, very large specimens can reach 8 mm. <br /> <br /> It is morphologically very similar to the sister-species L. rugatus which is genetically distinct and ranges between California, U.S.A. and Baja California, Mexico so the two species do not overlap in distribution. Minor differences that help to separate these two species include: the granulation of the valve sculpture is denser and stronger in L. rugatus, and L. rugatus also has smaller apophyses and thicker shell valves. <br /> <br /> These two species also appear to also differ in reproductive ecology, where field observations and population genetic data both support L. cascadiensis as a brooder with high site fidelity and very low dispersal ability, this is not the case for L. rugatus which is most likely a spawning species instead. Due to this unusual ecology, L. cascadiensis tends to occupy very small patches of habitat in each site where populations are maintained for decades. As such, it is best considered a locally common species that is overall uncommon across its range. Its distribution range is almost an exact match with the Cascadia bioregion and the Cascadia movement, from which it gained the specific epithet.
Meiocardia sanguineomaculata (Dunker, 1882)<br /> GLOSSIDAE<br /> -80m, Trawled, Off Surigao, Surigao del Norte, Philippines, 13.7 mm <br /> <br /> The "Blood-spotted Heart Clam" is an exquisite glossid characterised by a strongly curled shell with rounded outline, adorning numerous strong, broad concentric ribs and sparse dark reddish colour spots from which its name is derived. A rather widely distributed filter-feeding species in the Indo-West Pacific, it ranges between the Philippines and Seychelles where it inhabits coarsely sand bottoms of shallow to moderate depths between about 10~100 m depth. Despite its broad distribution, it remains a rather rare species. The shell morphology is little-varied except that the extent and coverage of the reddish speckled pattern can vary greatly among individuals. Typical shell length around 15 mm, very large specimens can exceed 25 mm. <br /> <br /> It is most similar to, and often confused with, the congener M. moltkiana (Gmelin, 1791) which has an even broader distribution range from Japan to Madagascar. The two main differences in shell morphology is that M. moltkiana has a more angular outline with the keel always ending in a sharp protrusion, and that the concentric ribs are much weaker and more frequent on M. moltkiana. Furthermore, M. moltkiana is a much larger species averaging at about 25 mm shell length with the largest specimens exceeding 40 mm; the concentric ribs also tend to weaken in adult shells of M. moltkiana whereas this is not the case in M. sanguineomaculata. Both species carry a similar colour pattern consisting of dark reddish patches, but in M. moltkiana the patches tend to be larger and more diffused compared the small, triangular speckles that usually occur on M. sanguineomaculata.
Choreotyphis pavlova (Iredale, 1936)<br /> MURICIDAE<br /> -240 m, Dredged, Off Cape Morton, Queensland, Australia, 16.8 mm <br /> <br /> With equally elongate and elegantly balanced siphonal canal and anal tube, the graceful "Pavlova Typhis" appears to be dancing -- and was aptly named in commemoration of the Russian prima ballerina Anna Pavlovna Pavlova (1881-1931), one of the most famous ballerinas of all time. There are four broad, rounded axial varices per whorl which converge like lotus petals on the spire. An instantly recognisable species, specimens are little-varied except the extent and development of reddish brown patches on the shell. Though the siphonal canal and the anal tube are always very long in the natural condition, in most specimens either or both are usually broken off and finding a well-balanced specimen with both intact is very challenging.<br /> <br /> It is a rare species and an endemic of eastern Australia, where it ranges between Queensland and New South Wales. A previous record of this species from New Caledonia was later found to be a different species and named Trubatsa wolffi (Houart, 2013). In the best specimens, both tubes can exceed the length of body whorl plus the spire. Found in moderate to deep subtidal waters between 50~500 m depth, its diet is unknown but is most likely a carnivorous and predatory gastropod feeding on other invertebrates as is typical for the family. The shell length is typically between 15-20 mm, but the largest specimens can approach 25 mm. <br /> <br /> Though originally placed in the genus Typhina when it was first described by the malacologist Tom Iredale, he also named the subgenus Choreotyphis (literally the "Dancing Typhis") at the same time to house this species. Today, Choreotyphis is treated as a full genus on its own right due to the anal tube directly originating from the varices and a complete lack of intervarical axial folds, although its separation from Siphonochelus and Trubatsa remains to be tested using molecular data. Before Choreotyphis became recognised as a full genus, many authors treated it under Siphonochelus. The only other extant species currently plaaced in Choreotyphis is C. erythrostigma (Keen & Campbell, 1964) also from eastern Australia, but that species exhibits strong spiral cords on the shell surface and is easily separable from C. pavlova.
Pteropurpura modesta (Fulton, 1936)<br /> MURICIDAE<br /> -200~250 m, Off Saga, Kuroshio-cho, Kochi Prefecture, Japan, 1990, 31.3 mm <br /> <br /> An exquisitely sculptured muricid endemic to Japan, Pteropurpura modesta exhibits three webbed, wing-like varices on strongly shouldered whorls, together with a slightly bent siphonal canal and an adapically keeled protoconch. A rare species, it has a rather narrow distribution range in central Japan ranging from Kagoshima Prefecture in the south to Chiba Prefecture in the north. It is typically dredged on sand and rubble bottoms of moderate depths between around 30~250 m deep. Its diet is unknown, but it is assumed to be a predatory gastropod like other muricids that feed on other invertebrate animals like bivalves. <br /> <br /> Though it is a little-varied species in shell form with the exception of the extent of wing development, it can be variable in colouration. Vast majority of specimens are uniformly tan to light brown in colouration, but the background colour can also be white to cream. In some specimens, dark reddish brown blotches can also occur which may be closely spaced and form up to three spiral bands. Typical shell length around 30 mm and adults are remarkably consistent in size; even very large specimens rarely exceed 35 mm. <br /> <br /> Previously, this species has been referred to as P. stimpsoni (Adams, 1863) which is actually an older name compared to P. modesta. Though P. stimpsoni is indeed potentially a senior synonym of P. modesta, the problem is that P. stimpsoni was described using minimal text without figures, and the type is apprently lost from the Natural History Museum in London. As such, P. stimpsoni could actually be any of the many species of three-winged muricids from Japan and its real identity cannot be ascertained as of now. For now, it is best to treat P. stimpsoni as a nomen dubium and use P. modesta, the earliest name that certainly refers to this species. <br /> <br /> It is often confused with the congener P. plorator (Reeve, 1849) which is a much more common three-winged species that co-occurs in the same habitat. Close examination will reveal that P. plorator has smoother, less angular whorls and typically wider varices; P. plorator is also a much larger species that can attain 80 mm in shell length.
Triviella sanctispiritus (Shikama, 1974)<br /> TRIVIIDAE<br /> -55 m, Trawled on reef, Off Port Elizabeth (Gqeberha), Eastern Cape, South Africa, 21.3 mm <br /> <br /> The "Holy Spirit Trivia" is a very large triviid endemic to South Africa, characterised by an inflated, spherical shell ornamented with branching, irregular dorsal ribbing. The dorsal ribs are fine and usually forking especially near the margins, the dorsal sulcus is indistinct. Originally named by the late Japanese malacologist and palaeontologist Tokio Shikama (1912-1978) based on a specimen he obtained from Taiwanese trawlers working in South Africa, the exact type locality remains unclear. The holotype was a 27.6 mm specimen with incomplete dorsal ribbing (possibly not fully mature), it was not donated to a museum but instead placed in the Shikama collection and was unfortunately lost after his passing. <br /> <br /> Specimens identifiable as this species with confidence have only been collected from the Eastern Cape province, where it ranges between Coffee Bay and Algoa Bay between about 50~100 m deep. No information is available on its ecology, but it is most likely a carnivorous gastropod feeding on colonial tunicates like other triviids. Typical shell length around 20 mm, very large specimens are known to exceed even 30 mm. The specific epithet literally means "holy spirit", but Shikama did not explain the reasoning behind this name in his description paper. <br /> <br /> One of the most sought-after triviids, it is a very rare species that has a history of being confused with other Triviella species in the same geographic region. Almost all specimens that have been offered under this name have been trawled between Cape St Francis and Jeffreys Bay to the west of Algoa Bay, and are characterised by a more ovate (less spherical) shell with more thickened lips when mature with a strong projection on the labral shoulder. These specimens have now been separated as a separate species, T. lorenzi Fehse, 2016; which also typically exhibit dark reddish spots on the centre of the dorsum. Triviella martybealsi Fehse, 2016 is another large species co-occurring with T. lorenzi but is easily separated by its pyriform shell and the deep dorsal sulcus free of any ribbing. Another species that T. sanctispiritus has been confused with is T. splendidissima Tomlin & Schilder, 1934 that also occurs in the northern Eastern Cape province, but T. splendidissima has a much narrower aperture, much denser dorsal ribbing and is much smaller, rarely exceeding 15 mm in shell length.
Vesicomya katsuae Kuroda, 1952<br /> VESICOMYIDAE<br /> -360 m, Trawled on sand and mud bottom, East China Sea, 2014/vi, 18.4 mm <br /> <br /> The first vesicomyid clam species described from waters around Japan, the "Katsu's Calypto Clam" is known from central Japan to Taiwan between about 150~500 m deep. Although placed in genus Vesicomya at the time of its description, typical members of Vesicomya are much smaller with shell length around 5 mm and their shells are much more spherical and thinner. The thick, chalky shell of V. katsuae suggests that it does not belong to subfamily Vesicomyinae but in fact subfamily Pliocardiinae which have sulfur-oxidising symbiotic bacteria in their gills. Some authors have previously transferred it to the pliocardiine genus Waisiuconcha, but the morphology is significantly different from that genus too and it may requires a new genus. Inhabiting muddy bottoms, it probably relies on endosymbiotic bacteria for nutrition like other members of Pliocardiinae. <br /> <br /> The holotype was trawled from about 180 m deep off eastern Kochi Prefecture, Japan. Subsequently, some specimens were found from deeper waters in Sagami Bay between 800~1400 m and tentatively identified as this species -- but the hinge morphology and shell thickness differ significantly and those deep specimens appear to represent a different, undescribed taxon. Typical shell length around 15 mm, very large specimens can reach 20 mm. The species name "katsuae" was given in honour to Katsu Teramachi, wife of the prominent Japanese shell collector Akibumi Teramachi who sampled and discovered many new species of molluscs around Japan.
Lirapex pantagruel Chen, Pradillon, Diaz-Recio Lorenzo & Alfaro-Lucas, 2025<br /> PELTOSPIRIDAE<br /> Holotype (MNHN-IM-2000-39946)<br /> -3993 m, On a black smoker chimney of Falkor EMARK vent field (23.4735°N, 44.9866°W), Mid-Atlantic Ridge, Northern Atlantic Ocean, Sampled using the suction sampler of ROV SuBastian during dive #495 on-board R/V Falkor (too) cruise FKt230303, 2023/iii/23, 7.5 mm <br /> <br /> A skeneiform peltospirid snail endemic to deep-sea hydrothermal vents, Lirapex pantagruel is currently only known from the Falkor EMARK vent field on the Mid-Atlantic Ridge at 3993 m depth. It inhabits surfaces of black smoker chimneys where it forms dense aggregations next to another larger peltospirid, Peltospira gargantua Chen, Pradillon, Diaz-Recio Lorenzo & Alfaro-Lucas, 2025. The shell is coiled with about four whorls, the final quarter-whorl loosens abruptly leading to slight detachment of the adult aperture, as seen in most Lirapex species. Sculpture consists of fine, intermittent axial ribs that appear as dotted lines; they are most pronounced on the early whorls. The periostracum is thin, semi-transparent, greenish, and often covered with mineral deposits. <br /> <br /> Although a locally common species at Falkor EMARK vent field, its distribution is very limited in area and all known specimens were collected during a 2023 research cruise. With an average shell diameter of around 5 mm and the maximum recorded shell diameter of 7.6 mm, L. pantagruel is the largest known species in the genus. Its anatomy is typical for the genus and it appears to graze and deposit-feed on the bacterial mat growing on chimney structures. <br /> <br /> Morphologically the shell shape is most similar to L. politus Chen, Zhou, Wang & Copley, 2017 from the southwestern Indian Ocean, but that species lacks axial sculpture entirely. The axial sculpture, together with an adult body whorl that only slightly detaches from the previous whorl as opposed to a complete detachment like many other Lirapex species, serve to differentiate L. pantagruel. The specific epithet 'pantagruel' refers to Pantagruel, a giant in François Rabelais' 16th-century satirical novel series "Gargantua and Pantagruel". This name is a nod to both the very large size for the genus and its co-occurrence with P. gargantua.
Peltospira gargantua Chen, Pradillon, Diaz-Recio Lorenzo & Alfaro-Lucas, 2025<br /> PELTOSPIRIDAE<br /> Holotype (MNHN-IM-2000-39943)<br /> -3739 m, On a black smoker chimney of the Hydra hydrothermal vent field (24.9600°N, 45.5749°W), Mid-Atlantic Ridge, Northern Atlantic Ocean, Collected by the manipulator of HOV Nautile with a chimney sample during dive #2099 (BICOSE3 dive #17), R/V Pourquoi pas? cruise BICOSE3, 2023/xi/16, 22.5 mm <br /> <br /> A large peltospirid endemic to the Mid-Atlantic Ridge, Peltospira gargantua is currently known only from two deep-sea hydrothermal vent fields including Hydra and Falkor EMARK between 3700~4000 m deep where it forms dense aggregations on the surfaces of active black smoker chimneys. Investigation of its internal anatomy revealed a hypertrophied oesophageal gland occupying nearly 14% of its body volume. This is similar to the condition of endosymbiotic peltospirid genera like Chrysomallon and suggests P. gargantua also rely on symbiotic bacteria capable of chemosynthetic primary production for nutrition, which would make it the first such gastropod in the Atlantic Ocean. <br /> <br /> The shell is globose and covered by a tough greenish periostracum which is often obscured by mineral deposits. The sculpture consists of narrow axial ribs that tend to fade with growth, being most prominent in early whorls. The ribs are sometimes broken into a number of nodule-like features, especially on the adult body whorl. The operculum is lost in adults. With a typical shell diameter around 20 mm and reaching up to 25 mm, P. gargantua is the largest species in the genus -- likely linked to its likely symbiotic feeding ecology. <br /> <br /> Although locally common, its distribution is very limited and all known specimens were collected during two scientific expeditions in 2023. It is most similar to the only Atlantic congener P. smaragdina Warén & Bouchet, 2001 which is a much smaller species that only reaches about 12 mm in shell length. In P. smaragdina the axial ribs are typically not weakened even in the adult body whorl, and the morphology of the epipodial tentacles also differ greatly between the two species where P. smaragdina only has ~10 small tentacles compared to P. gargantua which possesses 24–28 short, paddle-like tentacles. The specific epithet 'gargantua' is taken from François Rabelais' 16th-century satirical novel series "Gargantua and Pantagruel", alluding the extraordinary body size of this species to the giant king Gargantua.
Neancistrolepis beringiana (Dall, 1919)<br /> BUCCINIDAE<br /> -250 m, Trawled on sand, Sea of Okhotsk (58°59.6'N, 156°56.3'E), Off western Kamchatka Peninsula, Russia, 2018/vii, 133.1 mm <br /> <br /> A large cold-water buccinid found in the western Bering Sea and Sea of Okhotsk, Neancistrolepis beringiana is characterised by inflated, rounded whorls constricted by a deep suture. The greenish, shiny periostracum is thin and easily detached after drying. Surfaces of the earlier whorls are typically corroded away. Inhabiting sandy to muddy bottoms of moderate depths between about 50~300 m deep, it is a carnivorous gastropod feeding on other invertebrates and possibly also carrion. A rather rare species, its type locality is off Starichkoff Island of Kamchatka, Russia in the Bering Sea. It is generally a little-varied species, except some differences in shell height-to-width ratio among individuals. Typical shell length around 110 mm, very large specimens may reach 140 mm. <br /> <br /> Originally described as Ancistrolepis beringianus, but the specific epithet did not agree in gender with the genus name and was corrected as A. beringinana; it then became the type species of genus Neancistrolepis. A subspecies name N. beringiana dalliana Habe & Ito, 1973 was given to Sea of Okhotsk specimens with narrower shells, but this is now known to be within a continuum of morphological variability in N. beringiana and this name is usually considered a junior synonym. A well-developed anterior siphonal canal and the stronger suture constriction separates this species from the only congener N. glabra Habe & Ito, 1973 also from the Sea of Okhotsk; adult shells of N. glabra also tend to exhibit flared outer lips, a feature lacking in N. beringiana.
Crassicantharus noumeensis (Crosse, 1870)<br /> DOLICHOLATIRIDAE<br /> -20 m (-65 ft.), Dived on muddy rubble, North Shore, Oahu, Hawaii, U.S.A., 12.8 mm <br /> <br /> The aptly named "Gold-Banded Latirus" is a vibrantly coloured species belonging to the family Dolicholatiridae, characterised by an almost psychedelic pattern formed by elegant golden spiral bands occasionally inserted on a base pattern of alternating black and white zebra spiral lines. The shell appears knobby, with strong axial ribs intersecting the much finer spirals. When alive the head-foot is adorned with similar patterns as the shell, but even more elaborate as there is an added element of black dots. <br /> <br /> Originally described from New Caledonia (hence the name 'noumeensis', referring to Nouméa), it is now known to be a very widely-distributed species found across the Indo-Pacific and has been collected from distant localities such as Hawaii, Japan, Marshall Islands, Australia, and even Réunion and Mauritius. A carnivorous and predatory gastropod, it feeds on other small invertebrate animals. An uncommon species inhabiting sand to rubble bottoms of coral reefs in shallow depths between 10~30 m deep, the shell is usually heavily encrusted and requires careful cleaning. Average shell length around 15 mm, very large specimens may reach 25 mm. <br /> <br /> The polychromatic shell easily separates it from all other congeners, although there is one other dolicholatirid with a very similar colouration -- Teralatirus festivus (Haas, 1941). Currently Teralatirus is considered to be an Atlantic genus and the similarities in their colouration has been suggested to be coincidental, although this hypothesis has not been tested using molecular evidence. Apart from the distribution, these two species are also morphologically separable as T. festivus has much weaker axial ribbing and a broader shell.
Eocylichna sigmolabris Habe & Ando, 1985<br /> CYLICHNIDAE<br /> Off Hiroshima, Hiroshima Prefecture, Japan, 2006/vi/28, 4.0 mm <br /> <br /> Native to a region in the northwestern Pacific from central Japan to the East China Sea, Eocylichna sigmolabris is a cylichnid characterised by the unique strongly curved aperture shape resembling a sigmoid curve or the letter 'S' -- earning the species its name sigmolabris ("sigma-lipped"). The original description was based on the holotype collected as an empty shell mixed in sands from an artificial beach in Akashi City, Hyogo Prefecture in Japan; the sand supposedly originated from Mihara City in Hiroshima Prefecture taken between 10~20 m deep. Since then it has been an exceedingly rare species known from just a few empty shells and no live-collected individual were found for nearly 30 years. Many questioned the validity of this species and whether it could just be a 'freak' form of another species, but in July 2014 a live adult specimen was finally discovered in Osaka Bay. The head-foot is plain white, while the visceral mass is light orange.<br /> <br /> Majority of the specimens known are from Japan and a couple of records exist from Taiwan and eastern China. Most specimens have been beached after storms, but the natural habitat is thought to be low intertidal to subtidal waters down to about 50 m deep on fine sandy bottoms. Although no specific ecological information is available for this species, it is probably an infaunal species feeding on foraminifera like other cylichnids. Typical shell length around 4 mm, very large specimens may reach 6 mm. Due to its rarity and fascinating shell morphology, it was selected as one of 30 "Mystical Molluscs" in the 2025 exhibition "Obsessed with Shells - 300 Years of Malacology in Japan" in the Osaka Museum of Natural History.
Berthelinia limax (Kawaguti & Baba, 1959)<br /> JULIIDAE<br /> Found on Caulerpa algae, Below low tide line in a coral lagoon, Nashiro, Itoman, Okinawa Island, Japan, 2025/iv, 4.0 mm <br /> <br /> In 1959, the malacological world was shaken by the report of the first bivalved gastropod found alive -- Berthelinia limax discovered by Japanese marine biologists Siro Kawaguti (1908-2004) and Kikutaro Baba (1905-2001). The sacoglossan family Juliidae was originally described based only on fossil material and for a long time was placed in Bivalvia, but this finding led to the realisation that this is in fact a unique gastropod family producing a bivalved adult shell. This was immediately followed by a series of new discoveries of living juliid species around the globe. <br /> <br /> In the early years, all living Berthelinia found in the Indo-West Pacific were thought to be this species, but later research found populations from different localities actually represent separate species. Today, the confirmed range of B. limax is from the Pacific side of central Honshu to Okinawa in Japan; specimens identified as this species have been recorded as far south as the Philippines, but whether they are truly the same species requires further studies. <br /> <br /> The mode of development from a single protoconch into two adult valves is remarkable. The larval shell (protoconch) is normal and coiled, but once it settles and undergoes metamorphosis the shell field splits into two to begin secreting two valves of the adult shell (the left valve is the original shell with the protoconch, as seen in the figured specimen). The larval operculum is lost at this point, and the animal then develops an adductor muscle to hold the two valves together. <br /> <br /> Like all juliids it lives on and feeds exclusively on fluids of the green algae genus Caulerpa ('sea grapes'), this species is most often found on Caulerpa okamurae Weber Bosse 1897; the green colour of the shell and also the soft parts is considered to be an effective camouflage. Juliids secrete an unusually strong and adhesive tether made from mucus, with which they use to stay attached to their host Caulerpa since their survival depends on this. Currently, the most plausible hypothesis for the reason behind this group evolving the unique bivalved shell is so that they can fully retract into the shell while still attach to the host seaweed using this mucus tether. <br /> <br /> Found in shallow waters from low tide down to about 10 m deep on Caulerpa around coral reefs, it is rarely collected mostly due to its camouflage and small size, it is probably actually quite abundant in the right habitat. Typical shell length around 4 mm, very large specimens can exceed 6 mm.
Helicostoa liuae Zhang, Shi & Chen in Zhang, Shi, Chen, Von Rintelen, Zhang & Lou, 2024<br /> BITHYNIIDAE<br /> -0.5 m, On limestone, Long River, Hechi, Guangxi, China, 2022; female: 5.7 mm, male: 2.5 mm <br /> <br /> The enigmatic genus Helicostoa contains the only freshwater snails to live a sessile life, cemented on river stones. The type species Helicostoa sinensis Lamy, 1926 was described based on over 200 snails on two boulders supposedly taken from Yangtze River in China, and placed in its own family Helicostoidae due to its unusual morphology and lifestyle. Remarkably, there were two types of snails on these boulders, one was flat and discoidal and called the "P type" while the other was smaller and tightly coiled with a taller spire and referred to as the "T type". These were long assumed to be two sexes of the same species, while a specimen of the "P type" was later designated as the lectotype of H. sinensis. Neither types have been recollected for over a century despite several extensive surveys of the Yangtze River fauna, making it a mythical genus. <br /> <br /> In a total surprise, the "T type" was rediscovered in tributaries of the Pearl River far south in China in 2022, leading to the realisation that the two "types" do not represent two sexes of one species but instead two distinct species. This is because the "T type" clearly exhibited a more fascinating sexual dimorphism of its own -- only the larger females are permanently cemented while the smaller males are actually free-living and look like normal snails. Only in the females, the original aperture becomes sealed during the cementing process and a secondary, bow-shaped aperture is formed on the adult body whorl; females lay their egg capsules within the shell cavity. This divergence between the two sexes allows the males to actively seek out mates, while the females are hypothesised to have evolved a sessile life for brooding or better maternal care. <br /> <br /> Molecular data from the fresh "T type" specimens and the dried tissue of the original "P type" H. sinensis confirmed that they are genetically divergent, and thus the "T type" was described as a new species -- H. liuae, honouring the late Chinese freshwater mollusc researcher Yue-Ying Liu. The same genetic data also revealed Helicostoa to be a specially adapted lineage within the freshwater littorinimorph family Bithyniidae, and therefore Helicostoidae was synonymised with Bithyniidae. Although the true "P type" H. sinensis has not been rediscovered, we can catch a glimpse of hope for its continued existence and rediscovery from the finding of H. liuae, given the two species were originally found on the same boulder. <br /> <br /> Currently H. liuae remains a very rarely seen species with few confirmed localities in Guangxi Province of China, and is a suspension feeder relying on algae and other organic matter in the river stream. Typical shell length around 5 mm in females and 2.5 mm in males, with the maximum recorded shell lengths being 6.75 and 3.51 mm, respectively.
Nataliavoluta sagena Veldsman & Veldsman, 2022<br /> VOLUTIDAE<br /> Trawled, Off Durban, KwaZulu-Natal, South Africa, 1984, 33.1 mm <br /> <br /> A recently named volutid endemic to South Africa where it appears to be restricted to the region off Tugela Bank approximately between Durban and Richards Bay, with one dubious record more south off Park Rynie. An uncommon species, specimens have been trawled or dredged on soft bottoms in moderate depths between 100~350 m deep. The specific diet of this species is unclear but it is most likely a carnivorous and predatory gastropod feeding on other invertebrate animals, similar to other closely related volutids. A little-varied species, there is some limited differences in spire height and strength of axial sculpture among individuals. Typical shell length around 35 mm, large specimens can reach 40 mm. <br /> <br /> Prior to the formal description, it has been considered a form of Nataliavoluta gilchristi (Sowerby III, 1902) for many years. The revision of South Africa volutes by Veldsman & Veldsman in 2022 restricted the name N. gilchristi to specimens with strong spiral sculpture across the entire shell generating a cancellate sculpture, while naming two new species where the spiral lines are restricted to the anterior one-third or less of the shell. One of these is N. sagena, while the other is N. everriculum Veldsman & Veldsman, 2022; all three species co-occur off Tegula Bank. <br /> <br /> The distinction between N. sagena and N. everriculum is subtle and remains debatable, with the main differences being N. sagena has a more elongate shell where the axial ribs are more frequent but weaker especially near the adult lip. Another difference seems to be that the shell is thinner and glassy in N. sagena but thicker and opaque in N. everriculum. These species were previously placed in genus Atheleta, but the genus Nataliavoluta was established to house some morphologically similar species. The monophyly of Nataliavoluta, and whether there is the need to subdivide Athleta require further studies.
Whittenia gittenbergeri (Vermeulen & Clements, 2008)<br /> DIPLOMMATINIDAE<br /> Gua Datok, Perak, Malay Peninsula, Malaysia, 2011/v/26, 1.3 mm <br /> <br /> With an unusual shell irregularly coiled through three different axis, Whittenia gittenbergeri is a diplommatinid landsnail only known from three limestone hills known as Gua Datok, Gunung Bercham and Gunung Kanthan in Perak, Peninsular Malaysia. The first two whorls are discoidal, then the coiling loosens and the axis shifts almost perpendicular to the initial whorls. After two more whorls along this new axis, the shell detaches again to grow outwards. The shell sculpture mainly comprises closely aligned axial ribs that become more extensive with growth, expanding at the adult aperture to form a holostomate lip. Numerous very fine spiral striae are also present throughout the shell, but only visible under magnification. Individuals vary somewhat in the angle of axis shifts, though the mode of coiling is overall consistent and it is an easily recognisable species. Although the diet of this species is unclear, it likely feeds on moss and lichen that grows on limestones like other diplommatinids. Typical shell length around 1.5 mm, very large specimens may reach 2 mm. <br /> <br /> It was named in honour of Dr Edmund Gittenberger, a malacologist at Naturalis Biodiversity Center, Leiden. Initially described in Opisthostoma, later the genus Whittenia was established to house this species and its sister species Whittenia vermicula (Clements & Vermeulen in Clements et al., 2008) following a molecular phylogeny study revealing they are only distantly related to other Opisthostoma species. These two Whittenia species are very similar in sculpture but differ in coiling pattern, with W. vermicula going through a further change in coiling mid-growth that is lacking in W. gittenbergeri.
Whittenia vermicula (Clements & Vermeulen in Clements et al., 2008)<br /> DIPLOMMATINIDAE<br /> Gunung Rapat, Perak, Malay Peninsula, Malaysia, 2007/ii/27, 1.2 mm <br /> <br /> A marvellous form with an uncoiled shell going through four changes in the coiling axis makes Whittenia vermicula one of the most extraordinary landsnails alive. The first whorl is tightly coiled and discoidal, but the second whorl detaches to grow outwards -- then changes the axis again to latch back on to the first whorl. Although diplommatinids are well-known to exhibit shifts in coiling axis reminiscent of heteromorph ammonites, four changes is the most numerous reorientations known from any gastropod and makes this species unique. <br /> <br /> During growth the shell goes through a total of three detachments and two reattachments, which is remarkably consistent among known specimens. The worm-like shell carries a dense series of closely spaced axial ribs that increase in strength with growth. These are crossed by very fine spiral striae that are only visible under magnification. The aperture in adults expands to form a shield-like extension, as is typical for the family. <br /> <br /> Only known from two limestone hills in Gunung Rapat and Gunung Tempurung of Perak, Peninsula Malaysia, it remains a very rarely seen species probably largely due to its minute size. Although the diet is unclear for this specific species, it likely feeds on moss and lichen that grows on limestones like other diplommatinids. Typical shell length around 1 mm, very large specimens can reach 1.5 mm. <br /> <br /> Initially named in the genus Opisthostoma, the genus Whittenia was later described to house this species and its sister species Whittenia gittenbergeri (Vermeulen & Clements, 2008) following a molecular phylogeny study revealing they are only distantly related to other Opisthostoma species.
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