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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.

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.
Laubierina peregrinator Warén & Bouchet, 1990<br /> LAUBIERINIDAE<br /> -1697 m, On a seamount in the western Pacific about 1250 km east of Guam (156°24.408'E, 12°14.556'N), Taken by a manipulator of HOV Jiaolong during R/V Shenhai Yihao cruise DY86, 2024/ix/10, 13.2 mm <br /> <br /> With a specific epithet meaning 'traveller', the laubierinid snail Laubierina peregrinator is indeed a species that can travel afar with a very long planktotrophic larval stage as inferred from its very large and multipiral protoconch morphology. This leads to an extremely wide distribution range across Atlantic, Indian, and Pacific oceans -- the type locality is in the southeastern Atlantic off the border between Namibia and South Africa, and it is also known from off Argentina, Mozambique, and a few seamounts in the western Pacific. A very deep-water species, its known bathymetric range is between 1700~3600 m deep. <br /> <br /> Like other laubierinids in situ observations of it living on stalked crinoids on at least two occasions indicate it as an obligate associate of crinoids. Discolouration and drill holes of the host crinoid, plus behaviour of extending the proboscis over the crinoids' calyx suggest it likely a parasite that feeds on the body fluids of the host or is coprophagous, or both. The reproductive ecology is also unusual in that the males are neotenic, already settling on crinoids and develop mature testis while still in their protoconchs; females are always larger and with teleoconch shell growth and thus this species is inferred to exhibit protadrous hermaphroditism (which likely also applies to other laubierinids for which there is less information available on reproductive ecology). The protoconch can reach 5.5 mm in size, reddish brown in colour and is covered by a strong, regular, reticulate sculpture. Adult shells are typically wider than tall, with the shell diameter averaging around 15 mm and very large specimens reaching 20 mm. <br /> <br /> A very rare species, it has only been collected a handful of times in deep-sea expeditions around the globe. It is currently the only species in the genus Laubierina. Young specimens collected from northern Atlantic and between Australia and New Zealand have been inferred to represent further undescribed species in the same genus based on slight differences in shell sculpture, although these may also represent morphological variation within L. peregrinator and requires future study to confirm.
Laminilabrum breviaxe Kuroda & Habe, 1961<br /> LAUBIERINIDAE<br /> -519 m, Attached on the stem of a stalked crinoid, Off Kikaijima (28°08.993'N, 129°52.912'E), Kagoshima Prefecture, Japan, Taken by suction sampler of ROV Hyper-Dolphin, R/V Natsushima cruise NT11-21, 2011/x/14, 40.1 mm <br /> <br /> The only laubierinid species with a nearly smooth shell apart from fine spiral striations, Laminilabrum breviaxe is so far known from a wide distribution range encompassing the entire Indo-West Pacific from Japan (type locality) to Australia to Madagascar to eastern South Africa. Unlike some other laubierinids with a cosmopolitan distribution, it has not been found in the Atlantic Ocean and seems to have a more restricted range. With a bathymetric range between about 200~1000 m, it is the shallowest-distributed of this deep-sea family. <br /> <br /> Imagery of live individuals on the seafloor has recently revealed it to be an associate of large stalked crinoids, living on the stem -- the exact relationship between them remains unclear but it seems most likely that L. breviaxe is either parasitic or coprophagous, or both. Previously, this species has been collected while attached on stalked crinoids in dredges, but lacking direct evidence of their association on the seafloor this was dismissed as fortuitous. <br /> <br /> The shell shape is somewhat variable in height to width ratio and the strength of the suture, though the sculpture always remains similar. An uncommon species, most specimens have been caught as by-catches of fishing boats working off Japan and Taiwan. With an average shell length of around 30 mm and the largest specimens reaching 50 mm, it is also the largest laubierinid species. <br /> <br /> For many years it was thought to be congeneric with Pisanianura grimaldii (Dautzenberg, 1899) and placed in that genus, but recently molecular phylogeny showed they should be placed in two separate genera. The same work also revealed that Pisanianuridae and Laubierinidae were mixed to form a monophyletic clade -- resulting in their synonymisation.
Pisanianura grimaldii (Dautzenberg, 1899)<br /> LAUBIERINIDAE<br /> -1445 m, On an antedonid feather star, On a seamount in the western Pacific about 800 km northeast of Saipan (151°10.8935'E, 20°25.8949'N), Taken by a manipulator of HOV Jiaolong during R/V Shenhai Yihao cruise DY86, 2024/viii/27, 25.6 mm <br /> <br /> Characterised by a cancellate shell sculpture where the intersections of axial and spiral ribs are drawn out to form weak nodes, Pisanianura grimaldii is a laubierinid gastropod with a cosmopolitan distribution. First described from 1287 m off Azores, it was later collected from a number of localities also in the southwestern Indian Ocean (off Mozambique and Madagascar) and western Pacific (off Japan, Taiwan, Mariana Islands, and New Caledonia) between the depth of 700~2200 m. Although it seems to be only uncommon in its local habitat, the difficulty in accessing its deep-water habitat means it is a rarely seen species in collections. <br /> <br /> The protoconch is pale yellow and is covered in a regular, cancellate, grid-like sculpture like other laubierinids. The teleoconch sculpture is variable in strength among individuals, and the cancellate sculpture is always obvious on the earlier teleoconch whorls but can become quite weak in the adult body whorl. <br /> <br /> It was originally described in Nassariidae as Hindsia grimaldii, until examination of the soft parts, radula, and protoconch revealed it as a tonnoidean. Nothing was known about its ecology, but recently the first in situ observation of this species in the deep sea revealed it to be an associate of crinoids (feather stars in this case) like other laubierinids. It is probably parasitic, coprophagous (feeding on the excrements of the host animal), or both, but this requires further study. Within Laubierinidae, it is the only species with a cancellate teleoconch shell sculpture and is therefore an easily recognisable species. <br /> <br /> Typical shell length around 25 mm, very large specimens may reach 40 mm. For many years it was placed in family Pisanianuridae together with Laminilabrum breviaxe Kuroda & Habe, 1961, but molecular phylogeny revealed that Pisanianuridae and Laubierinidae were mixed to form a monophyletic clade -- resulting in their synonymisation. Anura clathrata Dautzenberg & H. Fischer, 1906 described also from off Azores and Oocorys donghaiensis Xu, 1989 from the South China Sea are junior synonyms.
Akibumia orientalis (Schepman, 1909)<br /> LAUBIERINIDAE<br /> -2602 m, Attached to a Thalassometra feather star, On the southern Mid-Atlantic Ridge about 800 km southwest of Saint Helena (11°43.8'W, 20°33.6'S), Taken by a manipulator of HOV Jiaolong during R/V Shenhai Yihao cruise DY83-I, 2024/ii/18, 24.3 mm <br /> <br /> A unique and unforgettable species characterised by striking, extremely strong spiral keels, Akibumia orientalis is a laubierinid gastropod of mythical rarity. A cosmopolitan species occurring across Pacific, Indian, and Atlantic oceans between about 800~2600 m deep, this very wide distribution is achieved through a very prolonged dispersal period as planktotrophic larvae, indicated by its large, multispiral protoconch. <br /> <br /> Despite this it is known from only about 20 specimens worldwide. The holotype was collected from Banda Sea in Indonesia during the Siboga Expedition followed by one to two specimens each from off Japan, Australia, New Zealand, and Madagascar; later about a dozen specimens were collected in the Atlantic. Of these, only about five were collected alive. Nothing was known about its ecology until recently, when the first in situ observation was published showing it lives on crinoids and is most likely parasitic or coprophagous (feeding on the excrements of the host animal), or both. <br /> <br /> Typical shell length around 15 mm, very large specimens may reach 25 mm. The shell is white, thin, and semi-transparent, oerlaid by a thin layer of yellowish green periostracum. The strength of the major spiral keels can vary greatly among individuals even from the same locality, though they are always prominent; the shell surface is also further marked by finer spiral threads which are most obvious on the major keels. No living gastropod species can be confused with it, and its teleoconch sculpture is perhaps best compared to the extinct muricid genus Ecphora -- although the anterior siphonal canal and the columella are completely different. The genus Akibumia was named after the Japanese conchologist Akibumi Teramachi (1898-1978).
Cycloscala revoluta (Hedley, 1899)<br /> EPITOIIDAE<br /> -150 m, Trawled, Off Balicasag Island, Bohol, Philippines, 2009/xii, 5.3 mm <br /> <br /> With strongly disjunct whorls marked by crenulated varices, Cycloscala revoluta is a truly exquisite epitoniid despite its small size averaging around 4 mm and the largest specimens only reaching 8 mm. As indicated by its multispiral protoconch it appears to have a planktotrophic larvae with long dispersal duration and range, leading to a very wide distribution across the Indo-West Pacific from Hawaiian Islands to Japan to Australia to Red Sea. Recently, it was also reported from Saronic Gulf off Greece, certainly an artificial introduction from human activities. <br /> <br /> A little-varied species except the number of varices per whorl can vary between six to eight, and is instantly recognisable based on its unique shell morphology. Presumably a predatory and parasitic gastropod feeding on sea anemones between shallow to moderate depths, it has been found from about 10 m deep down to about 200 m. An uncommon species, most specimens have been taken in dredges but empty shells are also beached especially after storms. Cycloscala latedisjuncta (de Boury, 1911) is a synonym. <br /> <br /> It most closely resembles C. hyalina (Sowerby II, 1844), which differs by the varices being equal in strength around the entire whorl unlike in C. revoluta where there is a spine-like protrusion near the shoulder. Furthermore, C. hyaline also has a less uncoiled shell where the varices are still connecting the whorls. The two species have overlapping distribution ranges and are often found in similar habitats.
Veleropilina reticulata (Seguenza, 1876)<br /> NEOPILINIDAE<br /> -500 m, Trawled in shell grit, Capraia, Livorno, Tuscany, Italy, 2013/iv, 1.8 mm <br /> <br /> The most accessible member of the mythical molluscan class Monoplacophora, Veleropilina reticulata is a small species endemic to the Mediterranean Sea. First described from fossil shells collected in deep water Upper Pliocene to Lower Pleistocene deposits off Messina, Italy, it was originally thought to be a gastropod limpet and placed in genus Tectura (Lottiidae). Later it was recognised as a monoplacophoran and placed in genus Rokopella, which was then synonymised with Veleropilina. <br /> <br /> Most specimens known today have been dredged or trawled from either submarine fossil deposits (mostly Pleistocene) or found in shell grit between about 200~600 m deep, majority of specimens have come from off Italy or France. All known specimens so far have unfortunately been empty shells which are already quite rare. Some specimens do appear quite fresh and it seems likely that this species is still living today -- just extremely rare. <br /> <br /> The shell surface is characterised by very fine reticulated sculpture which it derives its specific epithet from. A small flattened area in the apex known as the 'apical cap' is entirely smooth; the reticulate pattern first starts as dense accretion of dense pits near the apical cap, becoming increasingly reticulate with growth. The diet and ecology of monoplacophorans are very poorly understood, the currently available evidences suggest they are most likely deposit feeders. <br /> <br /> For many decades it was confused with the congener V. zografi (Dautzenberg & Fischer, 1896) known from between 700~1300 m deep in the northern Atlantic Ocean outside of the Mediterranean Sea. Indeed, the two species are quite similar at first glance -- but they can be separated by the following highly consistent shell characters: 1) the smooth, flat apical cap is much smaller in V. reticulata (0.15 mm vs 0.25 mm in V. zografi), 2) the shell is narrower in V. reticulata (1.2 times as long as wide vs 1.3 times in V. zografi), and that 3) V. reticulata is much smaller (average shell length around 1.2 mm and the largest specimens not exceeding 2.5 mm, vs average length of around 4 mm and maximum length 5.4 mm for V. zografi).
Julia exquisita Gould, 1862<br /> JULIIDAE<br /> -6 m, SCUBA dived under coral rubble, Fort Kamehameha, Oahu, Hawaii, U.S.A., 1995, 3.2 mm<br /> <br /> This is a gastropod! Julia exquisita is a member of the sacoglossan gastropod family Juliidae, which is unique among all gastropod families in producing a bivalved adult shell. Juliidae was originally described based only on fossil material and for a long time was placed in Bivalvia -- until in 1959 when the Japanese marine biologists Siro Kawaguti (1908-2004) and Kikutaro Baba (1905-2001) discovered the first living species Berthelinia limax (Kawaguti & Baba, 1959) in Japan which shocked the malacological world. <br /> <br /> This was immediately followed by a series of new discoveries of living juliid species around the globe, and information on their remarkable mode of development. The larval shell (protoconch) is normal, coiled, and univalve, 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). 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'), and the shell colour 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 /> The species-level taxonomy of Julia is currently in a state of flux, with the name J. exquisita often being used for populations found throughout the Indo-Pacific. However, given their short larval duration and local dependence on Caulerpa each species is unlikely to have extensive ranges, and the name J. exquisita can only be safely applied to specimens of a similar morphology from around the type locality -- the Hawaiian Islands. Found in shallow waters from low tide down to about 10 m deep on Caulerpa ambigua algae around coral reefs, despite being a diurnal species live individuals are rather rarely seen likely due to their small size and camouflage; disarticulated valves are commonly found in sand pockets and so it is probably actually quite abundant in the right habitat. Typical shell length around 3 mm, very large specimens can exceed 5 mm.
Morum exquisitum (Adams & Reeve, 1850)<br /> HARPIDAE<br /> -15~20 m, Dived, Lamakera, Solor Island, Lesser Sunda (Nusa Tenggara) Islands, Indonesia, 2025/i, 25.8 mm <br /> <br /> Among the most sought-after and iconic of all collectible molluscs, the "Exquisite Morum" is characterised by a spellbinding purple-pink parietal shield dotted with whitish pustules and a dark protoconch coloured in deep pink or red. First discovered during the 1843-1846 expedition of HMS Samarang to the Indo-West Pacific, it was described based on a single specimen collected between 30~36 m deep in Sulu Island, Philippines. Since then, it has remained an exceedingly rare species. <br /> <br /> Due to its scarcity and a lack of published photographs, until about 1980 it was confused with other species especially M. kurzi Petuch, 1979 and M. ponderosum (Hanley, 1858). This has led to some sources citing its range to include southern Japan and Australia, now known to be based on misidentified records. In fact, all confirmed records of M. exquisitum have been from the Philippines in the Sulu Archipelago, until the recent discovery of several specimens in the Lesser Sunda (Nusa Tenggara) Islands, Indonesia. <br /> <br /> It inhabits shallow to moderate depths between 5~50 m deep, and although there is no information on its diet it is probably a carnivorous and predatory gastropod feeding on small crustaceans like other Morum species. It is instantly recognisable from the colour and morphology of the parietal shield, though specimens do vary somewhat in number of varices per whorl and size of the parietal shield. Typical shell length around 35 mm, it is quite variable in adult size like a number of other Morum species and the largest specimens can exceed even 45 mm. <br /> <br /> It is most similar to M. ponderosum (Hanley, 1858), though that species can easily be separated from having a yellow-orange parietal shield lacking white pustulation. The only other Morum species with a purple parietal shield is the also extremely rare M. veleroae Emerson, 1968 endemic to Cocos Island off the Pacific side of Costa Rica, but M. velaroae lacks nodulose axial ribs and the two species cannot be confused.
Plectostoma grandispinosum (Godwin-Austen, 1889)<br /> DIPLOMMATINIDAE<br /> On limestone wall covered with moss and lichen, Northern side of Niah National Park, Bukit Bekajang, Miri, Sarawak, Malaysia, Borneo Island, 5.7 mm <br /> <br /> Doplommatinid snails in the genus Plectostoma are famed for their irregular coiling and intricate ornamentation, among which Plectostoma gradispinosum is perhaps the most morphologically extravagant species. Initially in the first whorls the coiling is regular with the growth of numerous long, open spines just above the suture, but later the axis is shifted abruptly and the coiling direction reverses. In adults, the aperture opens near the apex which is largely concealed by the greatly expanded apertural shield. The change in coiling axis 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. <br /> <br /> The shell is thin and translucent, the whorls carry a golden hue while the spines are white. It is a little-varied species except slight variability in the spine development. Restricted to limestone outcrops and cave systems in Sarawak, Malaysia in Borneo, it is a herbivorous grazer feeding on mosses and lichens growing on the limestones. Although a locally common species in its local habitat, its range is quite restricted leading to its scarcity in collections. Among the largest Plectostoma species, the average shell length is about 4 mm with the largest specimens reaching 6 mm. Its unique sculpture and large size means it cannot be confused with other described Plectostoma species.
Delectopecten thermus Lin in Lin, Peng, Chen, Xu & Qiu, 2025 <br /> PECTINIDAE<br /> Holotype (NSMT-Mo 79569)<br /> -962 m, Fukai Site, Higashi-Ensei vent field (28°26.11'N, 128°11.49'E), Okinawa Trough, Japan, By suction sampler on ROV KAIKO on Dive #724, 2016/xii/04, R/V KAIREI cruise KR16-16, 20.0 mm <br /> <br /> Only known from a deep-sea hydrothermal vent in Okinawa, Japan at 962 m depth, Delectopecten thermus is a small pectinid with transparent valves. The valves are intricately sculptured with commarginal rows of scales and spinose radial ridges. Living attached to hard substrates near diffuse flow venting areas where weak discharges of geofluids rich in hydrogen sulfide and other reduced chemicals powering chemosynthetic primary production by microbes, it is the only Delectopecten species considered endemic to deep-sea chemosynthesis-based ecosystems. Due to the difficulty in collecting animals from such specific oasis-like habitats at great depths, only one specimen is currently known. Examination and analyses of the internal organs has shown that it is a filter-feeding bivalve and does not rely on symbiosis like many other hot vent fauna. <br /> <br /> Shell length of the holotype is 20 mm, at around the average size for species in the genus. It is most similar to congeners D. vancouverensis (Whiteaves, 1893) and D. gelatinosus (Mabille & Rochebrune, 1889), but can be distinguished by the auricle proportion, the anterior auricle of the left valve being curved inwards, and the byssal notch angle being at right angle (90°). The specific epithet 'thermus' is Latin for 'thermal', referring to its habitat in hydrothermal vents.<br /> <br /> (Original photos by Yi-Tao Lin)
Acesta maui Marshall, 2001<br /> LIMIDAE<br /> -450 m, Trawled along canyon wall, Chatham Rise, East off South Island, New Zealand, Leg. Norman Potter, 2002/xii, 100.8 mm <br /> <br /> A large deep-water limid endemic to New Zealand, the "Maui Giant File Clam" is characterised by a relatively elongate shell shape, reduced and recurved auricles, as well as weak radial sculpture. Found throughout waters around New Zealand, it lives attached to hard substrates between about 200~600 m deep and is a filter-feeding bivalve. Though not uncommon in its local habitat, it is difficult to collect given its rocky habitat in deep waters and is thus rarely seen in collections. Typical shell length around 120 mm, very large specimens may reach 160 mm. <br /> <br /> A thin layer of yellowish brown periostracum covers the shell, but is usually lost and not well-preserved in adult shells. A rather little-varied species, specimens do vary somewhat in shell outline and sculpture strength but always maintain the elongate-oval shape overall. It is a distinctive species among the Pacific members of genus Acesta and easily distinguished based on the shell form. Specimens of Acesta from southwestern Australia has sometimes been attributed to this species, but they have much more rounded shell shape and is currently considered to represent a separate species that may be undescribed.
Aristovasum cassiforme (Kiener, 1840)<br /> VASIDAE<br /> -25 m, By lobster net, Recife, State of Pernambuco, Brazil, 87.5 mm <br /> <br /> With its sophisticated shell morphology combining dense spines and an expansive, purplish parietal shield, the “Helmet Vase” is one of the most renowned and representative species of Vasidae. Endemic to Brazil between the states of Rio Grande do Norte and Bahia, it occurs in shallow to moderate depths between the extreme low tide to about 50 m deep. A carnivorous and predatory species, it feeds primarily on polychaete worms but bivalves have also been found in the stomach contents. <br /> <br /> The shell morphology is quite variable in terms of spine development and the extent of parietal shield. The shoulder spines, for example, can either be blunt, short nodes or drawn out to form long, empty spines (shown). Rarely, some individuals with white parietal shields can also be found and are traded as "albinos" among shell collectors. Though a locally common species, it is not easy to find a high-quality specimen with intact, long spines. Typical shell length around 80 mm, extremely large specimens can exceed even 110 mm. <br /> <br /> It was traditionally placed in the genus Vasum, but recently in a review of Vasidae (which also raised it to full family status from subfamily Vasinae of Turbinellidae) the genus Aristovasum was made to house this species. The only other species currently placed in this genus is the fossil A. chipolense from the Early Miocene of Florida, a probably precursor species of A. cassiforme.
Buccinum mysticum Shikama, 1963<br /> BUCCINIDAE<br /> -300~400 m, Trawled, Off Izu Ōshima, Tokyo, Japan, 63.2 mm <br /> <br /> The "Mystical Whelk" is a cold-water buccinid known for having a very narrow distribution range in central Japan, ranging between Shizuoka Prefecture and the Izu Islands just east of it. In addition to its restricted range, it seems to be a very rare species even in its local habitat. Most specimens known have been taken crabbed with considerable damage to the shell, live-collected specimens are truly scarce. It is immediately distinguishable from all other Buccinum species by its very broad subsutural ramp leading to each whorl having a sigmoid side profile, together with the shell being thick and sturdy. <br /> <br /> A carnivorous and predatory gastropod feeding on invertebrate animals, it inhabits sandy to muddy bottoms of moderately deep waters between 200~400 m depth. The periostracum is very thin and easily peeled, even in live specimens it is mostly lost naturally except the recently secreted part near the aperture. The shell form and size are both remarkably little-varied, with the typical shell length around 60 mm and the largest specimens reaching 70 mm. The shell colour can range from greenish to brownish.
Shinkailepas cornuthauma Gu, Chen, Gao, Zhou & Sun, 2025<br /> PHENACOLEPADIDAE<br /> -2920 m, Wocan hydrothermal vent field (60°31.8ʹE, 6°21.6ʹN), By HOV Jiaolong on dive #125, R/V Xiangyanghong 9 cruise DY38, March 2017, 6.7 mm <br /> <br /> Only known from two deep-sea hydrothermal vents on the Carlsberg Ridge in the northern Indian Ocean off Somalia between 2900-3500 m deep, Shinkailepas cornuthauma is a phenacolepadid limpet characterised by a near-central apex position and a very reduced septum. Only known from three individuals collected across multiple submersible dives, it appears to be a somewhat rare species in its local habitat which is inaccessible except with a deep submersible. <br /> <br /> The shell sculpture is dominated by very strong radial ribs which cross with weak concentric ones. The periostracum is semi-transparent and green in colour, though usually overlaid with a layer of black or rusty mineral deposit precipitated out of the hot vent fluid. A corneous operculum is present but is functionally obsolete, being positioned on the dorsal aspect of the foot that is not visible externally and cannot be used to close the aperture. Like other phenacolepadids, it uses haemoglobin instead of haemocyanin for oxygen transportation and thus its blood and soft parts are red in colour when alive -- hence the family's common name "red-blooded limpets". Typical shell length around 8 mm, the largest specimen known is 11.7 mm. <br /> <br /> The apex position, the strong radial sculpture, and the very reduced septum makes it an easily distinguished species among the known members of Shinkailepas. The specific epithet is a combination of Latin "cornu ('horn')" and Ancient Greek "thaûma ('wonder, marvel, astonishment'); it is partly inspired by the magical helm 'cornuthaum' from the roguelike video game NetHack, alluding its horn-like, curved apex to a witch/wizard hat.
Shinkailepas tiarasimia Gu, Chen, Gao, Zhou & Sun, 2025<br /> PHENACOLEPADIDAE<br /> Holotype (RSIO 38219), female<br /> -2920 m, Wocan hydrothermal vent field (60°31.8ʹE, 6°21.6ʹN), By HOV Jiaolong on dive #129, R/V Xiangyanghong 9 cruise DY38, March 2017, 5.3 mm <br /> <br /> A deep water phenacolepadid limpet with a silvery sheen, Shinkailepas tiarasimia is known from hydrothermal vent fields in the Indian Ocean where its confirmed range is from the northern Calsberg Ridge off Somalia to the southern Central Indian Ridge just southeast of Mauritius, between 2400-3000 m depth, between 2400-3000 m depth. It is uncommon in its local habitat, which is inaccessible without a deep submersible. <br /> <br /> The shell sculpture is cancellate with both concentric and radial sculptures that form weak nodes when intersecting; the concentric sculpture is relatively stronger. The apex is positioned near the posterior shell margin, and the septum occupies about one-fourth of the aperture. A corneous operculum is present but is tightly tucked into the dorsal aspect of the foot and is not visible externally; it is functionally obsolete. Like other phenacolepadids, it uses haemoglobin instead of haemocyanin for oxygen transportation and thus its blood and soft parts are red in colour when alive -- hence the family's common name "red-blooded limpets". Typical shell length around 5 mm, the largest specimen known is 8.4 mm. <br /> <br /> A combination of the apex position, the cancellate sculpture with stronger concentric lines than radials, an entirely corneous operculum, and only having 12-15 small epipodial tentacles distinguish it from all other described Shinkailepas species. The specific epithet is a combination of Greek words "tiára ('headdress')" and "asimía ('silver-coloured')", alluding the silvery sheen of the periostracum and its cap-like shape to oriental silver headdresses.
Turbo albofasciatus Bozzetti, 1994<br /> TURBINIDAE<br /> -200~300 m, Trawled off northeastern coast of Somalia, 16.7 mm <br /> <br /> Festively decorated in bands of purplish red and white, Turbo albofasciatus is a small turbinid with a very restricted distribution off Somalia where it is apparently endemic. Most specimens have been trawled off Ras Hafun where it inhabits soft bottoms between 100~300 m. Although its feeding ecology is not known, it most likely feeds either on algae or organic matter in the sediment, especially given its very deep bathymetric range for the genus Turbo. It has always been a very rare species, partly due to the prolonged political unrest in Somalia making it difficult to collect new material. <br /> <br /> A little-varied species, the only variable aspect of its shell morphology appears to be the development of the shoulder tubercles which has a clear impact on the overall shell outline. The colouration of the dark bands can range from red towards purple, depending on the specimen. The calcareous operculum is smooth, rounded and lacking in sculpture except a slightly depressed line running spirally from the centre to the edge. Typical shell height around 15 mm, very large specimens are known to exceed 20 mm. It cannot be confused with any other known turbinid species, with its unusual colouration combined with multiple rows of shoulder tubercles.
Palmulacypraea katsuae (Kuroda, 1960)<br /> CYPRAEIDAE<br /> -200 m, Trawled, Off Aliguay Island, Zamboanga del Norte, Philippines, 16.1 mm <br /> <br /> The "Katsu's Date Cowrie" is a small cypraeid characterised by a very narrow shell, always with well-stained teeth and poorly developed fossula carrying just two to four weak denticles. There has been some confusion on the identify of P. katsuae due to confusion with P. musumea (Kuroda & Habe, 1961), especially up until the mid-1990's. At the time, the name P. katsuae was erroneously used to refer to the true P. musumea (for which the well-known P. boucheti (Lorenz, 2002) is a junior synonym), a mistake that appears to stem from the original description of P. katsuae not illustrating the holotype specimen with sufficient clarity, with only three small drawings and no photographs. <br /> <br /> This misconception then led to the Taiwanese conchologist Tzu Chiao (T.C.) Lan describing the true P. katsuae again, under the name P. vicdani (Lan, 1985) honouring the Filipino conchologist and shell dealer Victor Dan, which we now know as a junior synonym of P. katsuae. The fact that Lan's vicdani and Kuroda's katsuae referred to the same species was first claimed by the German conchologists Felix Lorenz and Alex Hubert in their 1993 first edition of the "A Guide to Worldwide Cowries" based on the text from the original description mentioning that the fossula is deep and only carries four deepth; later confirmed by the Japanese conchologist Hitoshi Ikeda in 1998 when he described P. omii (Ikeda, 1998) and figured the holotype of P. katsuae in colour. Nevertheless, many specimens of P. katsuae was traded under the name vicdani on the shell trade market for some more years. <br /> <br /> A very rare species, P. katsuae ranges widely from southern Japan to Fiji in the western Pacific. Its distribution as we currently understand is disjunct, with one part extending from southern Japan to the Philippines and the other between New Caledonia and Fiji. Specimens from the latter part differs in having an even more slender shell with more numerous teeth, and is treated as a separate subspecies P. k. guidoi (Lorenz, 2002) which is even rarer than the nominal subspecies. Most specimens of the nominal subspecies between Japan and the Philippines have been trawled or taken by tangle nets between 100~300 m deep, while P. k. guidoi appears to be slightly shallower with most specimens coming between 80~150 m deep and one specimen was even collected alive at a depth of just 55 m. Both subspecies average at a shell length of about 15 mm, while very large specimens may approach 25 mm. <br /> <br /> Though P. katsuae shares its distribution range with P. musumea and P. omii, it is easily distinguished by its much more slender shell and the weak fossula; both P. musumea and P. omii exhibit well-developed fossula with many strong teeth. Another point is that mature shells of P. katsuae typically has a flattened apex protruding to the side, but this is much less prominent in the other two congeners. The name katsuae was given in honour to Katsu Teramachi, wife of the prominent Japanese shell collector Akibumi Teramachi who collected and donated the holotype specimen for study.
Palmulacypraea musumea (Kuroda & Habe, 1961)<br /> CYPRAEIDAE<br /> -150~200 m, Trawled, Off northeastern corner of Taiwan, 2020/vi/03, 20.2 mm <br /> <br /> Characterised by a well-calloused, pyriform shell usually with stained teeth, the "Daughter's Date Cowrie" a small cypraeid ranging from Japan to the Philippines to Fiji. Inhabiting moderately deep waters between about 100~500 m, its feeding ecology remains unclear and both sponge-grazing and deposit feeding are plausible. It used to be a rarely seen species in the early days when most specimens were supplied from Japan and Taiwan, now it is only uncommon species thanks to deep-water dredges operating in the Philippines. That being said, most specimens found in the Philippines are empty shells and live-collected specimens remain scarce. Typical shell length around 20 mm, very large specimens can come close to 30 mm. The name 'musumea' literally means 'girl' or 'daughter' in Japanese, apparently an allusion of its delicate colouration of the dorsum. <br /> <br /> The true identity of the name P. musumea has been perplexing for decades because although normally this species has stained teeth, the holotype turns out to be a worn and somewhat faded shell on which the teeth appear to be unstained; this is either due to the stains having been worn out on the shell or it may represent an unusual specimen that lacked stains on the teeth (a number of such specimens are now known). This has later led to the description of P. boucheti (Lorenz, 2002) as a separate species (named after Dr Philippe Bouchet of Muséum national d'Histoire naturelle, Paris), when it actually represents the more common form of P. musumea with stained teeth and all other conchological features match well with the holotype of P. musumea. As such, Palmulacypraea specimens with stained teeth and calloused, pyriform shells are referable to P. musumea and P. boucheti is its junior synonym. There is another name, 'lacrimula' Lorenz & Hubert, 2000, which is a taxonomically invalid moniker that also refers to the P. museumea form with stained teeth. Almost all Palmulacypraea specimens with unstained teeth are actually referable to a separate species, P. omii (Ikeda, 1998). The two species also differ by shell shape, as the posterior portion of the shell in P. omii is not strongly calloused like in P. musumea even when fully mature, leading P. omii to exhibit a teardrop-like shape instead of pyriform like P. musumea. <br /> <br /> Until the late 1990's, P. musumea was even confused with P. katsuae (Kuroda, 1960) which is another species with stained teeth, but P. katsuae has a much more elongate, narrow shell shape and lacks the well-developed fossula teeth seen in both P. musumea and P. omii, and is therefore easily differentiated. The early confusion between P. musumea and P. katsuae was due to a lack of clear illustration of the holotype of P. katsuae. Despite the abovementioned issues already correctly pointed out and clarified by Hitoshi Ikeda in his paper describing P. omii, these names are unfortunately still often muddled on the shell trade market -- P. omii is often called P. museumea and specimens of P. musumea with stained teeth traded as P. boucheti.
Palmulacypraea omii (Ikeda, 1998)<br /> CYPRAEIDAE<br /> -200~300 m, Dredged between Amami Ōshima and Yakushima, Kagoshima Prefecture, Japan, 1998/v; 20.2 mm <br /> <br /> A small cypraeid with a teardrop-shaped shell slightly widened at the middle and fine, unstained teeth, the "Omi's Date Cowrie" is best known from East China Sea where it ranges between southern Japan to Taiwan. Its distribution range is actually much wider however, with scattered records from as far as New Caledonia and French Polynesia. Inhabiting moderately deep waters between about 100~400 m, its feeding ecology remains unclear and both sponge-grazing and deposit feeding are plausible. It is a very rare species that is seldom seen, especially live-taken specimens, partly because of its deep habitat and that it has actually not been recorded yet from the Philippines where deep-water collecting is most practiced today. Typical shell length around 20 mm, very large specimens may exceed 25 mm. It was christened after the Japanese conchologist Yoshihiro Omi, who first recognised it as undescribed. <br /> <br /> This species has long been confused with the congener P. musumea (Kuroda & Habe, 1961). The two species shares a large part of their distribution ranges, as P. musumea is known from southern Japan to Fiji. The source of this confusion is that although P. musumea is a species that normally develops stained teeth, the holotype is a worn and somewhat faded shell on which the teeth appear to be unstained; this is either due to the stains having been worn out on the shell or it may represent an unusual specimen that lacked stains on the teeth (a number of such specimens are now known). This has later led to the description of P. boucheti (Lorenz, 2002) as a separate species, when it actually represents the more common form of P. musumea with stained teeth and all other conchological features match well with the holotype of P. musumea. <br /> <br /> As such, Palmulacypraea specimens with stained teeth and calloused, pyriform shells are referable to P. musumea and P. boucheti is its junior synonym -- as correctly pointed out already by Hitoshi Ikeda in his paper describing P. omii. Although P. katsuae (Kuroda, 1960) also has stained teeth, that species has a much more elongate, narrow shell shape and lacks the well-developed fossula with numerous distinctive teeth seen in both P. musumea and P. omii. Virtually all Palmulacypraea specimens lacking stained teeth are therefore P. omii, which is also typically much less calloused than P. musumea in adults. These names are unfortunately still often muddled on the shell trade market, with P. omii often called P. musumea and specimens of P. musumea with stained teeth traded under P. boucheti.
Gigantidas horikoshii Hashimoto & Yamane, 2005<br /> MYTILIDAE<br /> -694 m, Sumisu Caldera hydrothermal vent field (31°28.2113'N, 140°4.2833'E), Izu Arc, Japan, Taken during dive #1801 of the manned submersible HOV SHINKAI 6500 on-board research cruise YK24-13C, 2024/viii/22, 167.3 mm <br /> <br /> Characterised by an elongate shell with a laterally swollen umbonal region, the "Horikoshi's Deep-sea Mussel" is a large mytilid restricted to deep-sea hydrothermal vent fields in the northwestern Pacific. Specimens confirmed or inferred to be this species is currently known from just six locations from Izu-Ogasawara Arc, Okinawa Trough, and off Taiwan within a depth range of about 200~800 m deep. Though juveniles and subadults have been recovered from rocks and sulfur deposits near hot vents, adults always bury deep into hydrothermally influenced sediments rich in hydrogen sulfide with only 20-40% of the shell visible on the sediment surface. Like most other members of the subfamily Bathymodiolinae, it most likely hosts endosymbiotic bacteria inside cells of its gill which produces energy using the vent fluid through chemosynthesis. <br /> <br /> At the specific localities where it lives it occurs in great density and vast numbers, but given only a few such locations are known and they cannot be reached without scientific submersibles, it is a rarely seen species. Typical shell length around 130 mm, very large specimens are known to exceed 170 mm. It was named in honour of the Japanese deep-sea biologist Dr Masuoki Horikoshi of the Ocean Research Institute, the University of Tokyo. <br /> <br /> The most similar species is the congener G. gladius Cosel & Marshall, 2003 from hot vents around New Zealand, but it is easily differentiated as the shell of G. gladius is even more narrow and elongate, and also much larger (average shell length around 250 mm, largest specimens can exceed 310 mm).
Conus tisii Lan, 1978<br /> CONIDAE<br /> -150~200 m, Taken by net on a coral fishing boat, South off Pinnacle (aka. Senkaku, Diaoyu, Tiayutai) Islands, East China Sea, 150.4 mm <br /> <br /> Ranging from southern Japan to Taiwan to the Philippines, Conus tisii is characterised by a shell with a low domed spire and two darker bands on the body whorl. Widely considered to be one of the "holy grails" of cone collectors, it is an extremely scarce species and one of the most sought-after species of the western Pacific. A carnivorous and predatory gastropod, it inhabits moderately deep waters between 100~400 m deep. <br /> <br /> The shell shape and patterning are both somewhat variable as well as the overall shell height-to-width ratio, though the spire is always distinctly domed. Irregular very dark brown to black blotches mainly occur on the two darker bands on the body whorl but their density and extent of coverage are erratic and vary greatly among individuals, ranging from being completely absent to filling most of the bands. Smaller dark brown dots are sometimes also present just above the shoulder edge, especially in large adults. Due to an abrupt shift in shell growth pattern, the first few whorls protrude from the domed spire as a sharp tip; this is often worn away in mature shells. The base shell colouration is white, but fresh shells typically carry a lilac hue that fades over time. Typical shell length around 110 mm, very large specimens as shown are known to exceed 150 mm. <br /> <br /> It is most similar to Conus kostini Filmer, Monteiro, Lorenz & Verdasca, 2012 with which it was long confused. Compared to C. tisii, the shell of C. kostini is typically much lighter and more slender with a higher domed spire. The dark brown blotches on C. kostini is usually lighter-coloured than in C. tisii, and they are less defined to the main bands, often present extensively around the shoulder and extending on to the spire which is never the case in C. tisii. <br /> <br /> This species was first discovered as two trawled specimens off Taiwan and was then described by the eminent Taiwanese conchologist Tzu-Chiao Lan, who served as the President of the Malacological Society of Taiwan until his passing in 2004. The origin of the specific epithet "tisii" is puzzling. An etymology was not given for it in the description, though a widely alleged notion is that it is based on the English pronouciation of the alphabets "T.C." (initials of Lan's first name; Lan seldom used his first name in full and was usually referred to as T.C.). The rumour goes that Lan was under pressure from members of his malacological society that this large, spectacular new species should be named after him, but he also wanted to describe it himself. Though not prohibited in the International Code of Zoological Nomenclature, naming a species after oneself is broadly thought to be unethical and unprofessional. Perhaps using a perplexing name like "tisii" without a specific etymology satisfied his society while also allowed him to avoid clearly naming it after himself? Perhaps we will never know for sure.
Volutoconus vetulus Bail & Limpus, 2013<br /> VOLUTIDAE<br /> -135~145 m, Trawled, Southeast off Swain Reefs, Queensland, Australia, 82.3 mm <br /> <br /> The "Oldish Volute" is a volutid in the "Volutoconus grossi (Iredale, 1927) complex" from the eastern Australia, characterised by a dome-shaped protoconch carrying medium-spaced axial ribs and a deep-sutured, relatively low spire. The shell surface is wrinkled by numerous weak axial striae, much more closer-spaced than those on the protoconch. <br /> <br /> Ranging between Lady Musgrave to Swain Reef, it is typically trawled on soft bottoms between 100~300 m depth and all specimens have been empty shells. The current view is that V. vetulus is an extinct species and these shells represent young fossils that likely lived several tens of thousand years ago, well-preserved in anoxic mud but with lightened colourations. A rather rarely seen species, most specimens have originated from around Swain Reefs. It was likely a carnivorous and predatory gastropod like other volutids. Typical shell length around 90 mm, the largest specimens may reach even 130 mm. <br /> <br /> The most similar species is V. multiformis Bail & Limpus, 2013 which shares with it the wrinkled shell surface and a similar shell size, but the protoconch of V. multiformis is covered in more numerous axial striae that are much finer than those in V. vetulus. Another species that it might be confused with is V. keppelensis Bail & Limpus, 2013, which can be differentiated by a higher spire with less frequent and stronger axial ribs on the protoconch.
Pteropurpura plorator (Reeve, 1849)<br /> MURICIDAE<br /> -150~200 m, Trawled off Danjo Islands, Nagasaki Prefecture, Japan, 77.1 mm <br /> <br /> The "Expansive Murex" is a muricid with wing-like varices ranging from central Japan to Taiwan. A carnivorous and predatory gastropod feeding on other invertebrate animals, it inhabits rocky bottoms of moderate depths between about 100~200 m deep. A locally common species for which the main supply used to be gill nets in Japan but has recently shifted to Chinese trawlers operating in the East China Sea. The shell colouration ranges from light yellow to reddish brown, several spiral colour bands that can be either continuous or intermittent are typically present. This resembles the colour pattern on the flight feathers of some hawks, leading to its Japanese name "Hawk-feather Murex". The intervarical spaces are usually rather smooth and the only sculpture consists of low spiral threads. Typical shell length around 40 mm, extremely large specimens may reach 80 mm. <br /> <br /> The most similar species is P. esycha (Dall, 1925) with which it co-occurs in Japan; P. esycha has a more stout shell with strongly corrugated surface and a dorsally recurved siphonal canal. Most specimens of P. esycha offered on the market are misidentified P. plorator, the real P. esycha is very rare. Also often confused with other winged Ocinebrellus species from the same region like O. falcatus (Sowerby II, 1834), but P. plorator can usually be separated from them by a relatively smoother shell surface lacking major spiral cords and always having three varices per whorl.
Turbo excellens Sowerby III, 1914<br /> TURBINIDAE<br /> -15 m, Dived, Kumano Sea, Off Mie Prefecture, Japan, 19.2 mm <br /> <br /> Known as the "Brocade Turban Snail" in Japan for its intricate and variable patterns resembling woven textiles, Turbo excellens is a small turbinid snail endemic to southern Japan. Ranging between the Izu region just south of Tokyo and western Kyushu, it grazes on algae and inhabits rocky shores rich in red algae from low intertidal zone down to about 30 m deep. Up until about 1980's, it was thought to be a rather common species living among commercially important red algae (mainly Gelidium species, used for food and making agar) in Japan and was often collected from the algae as they were being sun-dried. However, in the recent decades it has declined drastically with few live individuals found across its entire range, making it a very rare species. This is most likely attributable to the changes in environmental conditions and algae growth, since the production of red algae has also greatly declined at the same time. <br /> <br /> The shell form is little-varied and always carry several broad spiral ridges; the base shell colour is always dark reddish brown but the markings are highly variable with various speckles of white, purple, yellow, green, and black scattered all over. Typical shell height around 20 mm, very large specimens can exceed 25 mm. Although the shell is somewhat similar to co-occurring congeners T. stenogyrus Fischer, 1873 and juveniles of T. sazae, its characteristic operculum with concentric deep furrows immediately differentiates it from those species as the operculum of T. stenogyrus is mostly smooth with just fine granules while that of T. sazae is covered in numerous spines.
Cymbiola malayensis Douté & Bail, 2000<br /> VOLUTIDAE<br /> -100~150 m, Dredged on mud / sand bottom, Sulu Archipelago, Philippines, Leg. Alain Allary, 2002, 137.4 mm <br /> <br /> The "Malay Volute" is a volutid native to a small region of the western Pacific around the Sulu Sea between Borneo Island and the Philippines, with the type locality being Pulau Kalapuan just off eastern Malaysian Borneo. The typical shell colouration is salmon pink, with two broad bands of a darker tone alternating with two lighter ones; the spiral boundary between the two is dotted with varying amounts of dark brown patches. Rarely, specimens with much darker-than-usual colours are found. The shoulder usually only bears weak, blunt nodes which fades in the adult body whorl. An uncommon species, it inhabits soft bottoms of moderate depths between about 50~200 m deep. Typical shell length around 110 mm, very large specimens can exceed 140 mm. <br /> <br /> A member of the C. aulica (Sowerby I, 1825) complex with large, bulbous, smooth protoconchs on oblong sylindrical shells; it is best identified by its weak shoulder nodes in combination with a colour pattern lacking axial flammules. There is some debate on whether it represents a separate species from the co-occurring C. aulica, but overall the morphological differences between the two are quite consistent even when considering the relatively wide range of variation seen in C. aulica, and they are thus currently treat as two separate species in most cases.
Aspidophoreas lamberti (Souverbie, 1871)<br /> XENOPHORIDAE<br /> -70~80 m, Dived on detrital sand, Sarcelles Pass, New Caledonia, Leg. Frank Hattenberger, 2006, 54.4 mm <br /> <br /> A rarely seen xenophorid, the "Lambert's Carrier Snail" is currently only known from New Caledonia. Inhabiting sand and gravel bottoms, it likely feeds on microalgae and foraminifera like other xenophorids. Vast majority of specimens have been collected as empty shells or crabbed between about 20~200 m deep, while live individuals have almost all been collected at around 80 m. In addition to living individuals, it has also been recorded as a Pleistocene fossil from Ouvéa Island of the Loyalty Islands, New Caledonia. It was named in honour of Reverend Pierre Lambert (1823-1903) of New Caledonia, like several other New Caledonian species described by Saint-Martin Souverbie. Typical shell diameter around 50 mm, very large individuals can exceed 75 mm. <br /> <br /> Originally described in the genus Xenophora, it was later moved to Stellaria where it stayed for about two decades until the genus Aspidophoreas was established for a small group of xenophorids including A. lamberti characterised by their extensive peripheral flanges. It is morphologically most similar to the congener A. chinensis (Philippi, 1841) which is widely distributed in the Indo-West Pacific, but differs most significantly in the stronger sculpture of the base, where the spiral cords are always much stronger than the radial ones. Another interesting difference is that A. lamberti is highly selective in the selection of its shell attachments which are typically always flat foraminifera tests; whereas A. chinensis uses a broad range of objects though mostly rocks and bivalve or gastropod shells. There are several more minor differences, such as the base of A. lamberti is more convex, and it also has a narrower umbilicus; the shell of A. chinensis is much larger, averaging at about 100 mm and the largest specimens may exceed 130 mm. Furthermore, the shell colouration of A. chinensis is typically yellow to reddish brown, but A. lamberti is always whitish.
Oocorys lussii Bozzetti, 1990<br /> CASSIDAE<br /> -400 m, Trawled, Off southern Mozambique, 33.3 mm <br /> <br /> The "Lussi's False Tun" is a deep-water cassid distributed in the Indian Ocean along the eastern Africa, with the holotype coming from South Africa and extending northwards up to Reunion. A carnivorous and predatory gastropod feeding on echinoderms like other cassids, it inhabits soft bottoms of rather deep waters around 300~800 m depth. Vast majority of specimens have been trawled as by-catches of fisheries off Madagascar and Mozambique. Quite a rare species, most specimens have been collected as empty shells or were crabbed. Typical shell length around 30 mm, very large specimens may approach 40 mm. It was named after the published South African conchologist Markus Lussi (1955~) who specialised in local molluscs and described many new species. <br /> <br /> Among Oocorys species, it is characterised by an intermediate spire height and a strongly cancellate, beaded shell surface. Some authors have considered O. lussii and several other names in the genus such as O. tosaensis (Habe & Azuma, 1959) and O. leejungi Lai, 2013 to be junior synonyms of the variable Oocorys verrillii (Dall, 1889) with a global distribution. This has however since been questioned given the morphological consistency of these taxa within their local populations. Given O. lussii is also little-varied morphologically within its range, it is more likely to be a valid species on its own right. Notably, O. morrisoni Kreipl & Alf, 2001 ranging from Western Australia to Vanuatu is geographically distant from O. lussii but extremely similar in morphology except that its shell is darker coloured, from bright cream to orange; as opposed to white to pale cream at most in O. lussii. To better understand the relationship between these taxa in Oocorys and their true distribution ranges, future testing using molecular data is warranted.
Entemnotrochus adansonianus bermudensis Okutani & Goto, 1983<br /> PLEUROTOMARIIDAE<br /> -350~500 m, Taken in trap, Main Island, Bermuda, 1988, 82.3 mm <br /> <br /> The "Bermudan Slit Snail" is a subspecies of the "Adanson's Slit Snail" Entemnotrochus adansonianus (Crosse & Fischer, 1861) endemic to Bermuda, geographically separated from the nominal subspecies which occurs widely from Gulf of Mexico to the Caribbean Sea to Brazil. It differs from the nominal subspecies in having a more vertically compressed shell with a strongly stepped spire and a more matte surface, darker flammule patterns which are deep purple-red, as well as a shorter but much broader selenizone (slit). The early whorls exhibit a sharper angle in E. a. bermudensis, and they are deep red in colouration as opposed to the typical yellow seen in the nominal subspecies. With an average shell diameter of just 60 mm and the largest specimens reaching 100 mm, E. a. bermudensis is also much smaller than the nominal subspecies which averages at around 110 mm and can even reach 190 mm. <br /> <br /> A very rare species due to its remote and restricted locality, the vast majority of specimens have been taken crabbed in deep-water traps between 200~500 m deep and only a few live-collected specimens are known. A carnivorous grazer feeding mainly on sponges like other pleurotomariids, it probably inhabits steep, vertical rocky walls like the nominal subspecies. Due to the greater rarity and therefore the associated price in the shell trade, many juvenile specimens of the nominal subspecies have been sold as E. a. bermudensis with false locality data; though the clear morphological differences between the two make such masquarades easy to detect.
Conus thailandis da Motta, 1978<br /> CONIDAE<br /> -40 m, Dived in sand and rubble, Off Racha Islands, Phuket, Thailand, 2021/xii, 59.7 mm <br /> <br /> A vivid reddish brown shell overlaid with sparse, irregular white blotches characterises the "Thailand Cone", a conid ranging between Andaman Sea and southern Vietname with vast majority of specimens known from off Phuket, Thailand. A carnivorous and predatory snail feeding on other molluscs, it inhabits sand and rubble bottoms around coral reefs in subtidal waters between about 10~50 m deep. An uncommon species, it is rather prone to growth scars and specimens with uninterrupted growth are rare. Typical shell length around 60 mm, very large specimens can approach 90 mm. <br /> <br /> It is often placed in the subgenus Darioconus, which many accept as a full genus. Originally described as a subspecies of C. crocatus Lamarck, 1810 which has a very wide distribution throughout the Indo-West Pacific from Japan to Australia to Mozambique, the relationship between these two taxa has been a topic of much debate. Recently, they have mostly been treated as two distinct species, but molecular data is sought to serve as a separate line of evidence to settle this debate. The main differences between the two taxa are that C. crocatus 1) has a typically narrower shell with less concave, taller spire; 2) shell patterning consists of much smaller and more numerous white bloches; and 3) usually has a brighter shell colouration closer to orange rather than dark mahogany in C. thailandis.
Harpa major Röding, 1798<br /> HARPIDAE<br /> -100~150 m, Taken in crab trap, Leeward Islands, Hawaii, U.S.A., 69.0 mm <br /> <br /> The "Major Harp" is a harpid snail with a very wide distribution from Hawaiian Islands in the central Pacific to Japan and Australia to South Africa. With an average shell length around 80 mm and rare giants attaining 130 mm, it is the largest living species of the family. A common species inhabiting sandy bottoms below low tide to moderate depths around 200 m deep, it is a carnivorous and predatory gastropod feeding on small crustaceans, especially crabs. Like other Harpa species it is capable of autotomising a part of its foot as a decoy when attacked by predators. A very variable species in terms of varix and glaze development as well as shell colouration, a number of synonyms have been given to deceptively dissimilar forms that intergrades with the typical form when a large series is examined. Two consistent conchological features are the singular, usually triangular parietal blotch and the lack of dentition on the outer lip. The overglazing of the early whorls is the most extensive among all Harpa species, often completely engulfing the protoconch. <br /> <br /> Figured here is H. major f. conoidalis Lamarck, 1822 -- characterised by a darker colouration and usually less overglazed early whorls than shallow water specimens. Though often attributed to deep-water specimens collected between 100~200 m depth from the Hawaiian Islands, the locality of the type specimen is actually unknown and similar colourful specimens have been collected from deep waters throughout the Indo-West Pacific. As such, it seems to be a variation of H. major linked to depth. An inflated form with narrow varices was described as Harpa kawamurai Habe, 1970 but now thought to be a mere form of H. major. The name H. davidis Röding, 1798 from Bay of Bengal with a similar morphology to H. major f. kawamurai is typically treated as a distinct species but possibly represent another local form of H. major.
Lunulicardia retusa (Linnaeus, 1767)<br /> CARDIIDAE<br /> Trawled, Shallow water on sandy bottom, Off Hainan, China, South China Sea, 35.6 mm <br /> <br /> Widely distributed throughout the Indo-West Pacific from Japan to Australia to South Africa, the "Blunt Cockle" is a cardiid characterised by a deeply impressed, wide lunule. The shell morphology appears to be rather variable, especially in terms of valve thickness and inflation. Inhabiting sandy bottoms of shallow waters down to about 50 m deep, like many other cardiids it has established symbiosis with photosynthetic dinoflagellates and rely on them for energy. Each local population tends to exhibit similar characteristics, although whether this is a result of plasticity due to environmental differences or genetic divergence warrants further studies. <br /> <br /> Although supposedly common, live-collected specimens are surprisingly difficult to come by. Most shells are white but sometimes they can be dotted with irregularly distributed red blotches; thin, yellowish periostracum covers the shell in fresh specimens. In Kagoshima Bay of Japan, empty shells of this species are commonly found on beaches in low tide but these are 'semi-fossils' from a population thousands of years ago and no living individuals have been found in the bay. Typical shell length around 35 mm, very large specimens may approach 50 mm. <br /> <br /> It is sometimes confused with the congener L. hemicardium (Linnaeus, 1758) with a similar wide distribution, but they can be easily distinguished as L. hemicaridum lacks the deep lunule. A more similar species is L. auricula (Niebuhr, 1775) from the Red Sea which used to be considered as a subspecies of L. retusa. These two species are very similar, but L. auricula is typically more inflated and carry numerous short spines on the ribs.
Athleta kilburni (Rehder, 1974)<br /> VOLUTIDAE<br /> Trawled, Off Durban, KwaZulu-Natal, South Africa, 1990's, Leg. Werner Messier, 49.7 mm <br /> <br /> The "Kilburn's Volute" is a deep-water volutid native to southern Africa, ranging between KwaZulu-Natal, South Africa to Mozambique. It differs from all other Athleta species by having a sunken, canal-like suture whose shoulder is almost completely smooth, and a shell surface sculpture consisting of numerous fine axial striae but lacking any distinct spiral lines. The shell is very thin with lustrous surface, often carrying different degrees of irregular reddish brown blotches. Presumably a carnivorous and predatory gastropod like other volutids, it inhabits soft bottoms of the continental shelf between about 200~500 m depth. A scarce species, most shells have been trawled from deep water while being carried by hermit crabs; live-taken specimens are very rare. Typical shell length around 40 mm, very large specimens may approach 60 mm. <br /> <br /> It was named in honour of the South African malacologist Dr Richard Neil "Dick" Kilburn (1942-2013) who worked at Natal Museum and described many new species of molluscs. In 2022 it was briefly placed in a newly named genus Afriathleta along with some other African volutes due to the claim that Athleta is based on fossil taxa that may not be closely related with living species. Shortly after, this claim was refuted in 2024 and it was placed back to Athleta.
Conus adami Wils, 1988<br /> CONIDAE<br /> Trawled, Arafura Sea, Northern Australia, Australia, 1989, Ex-coll. Kiyoshi Itoh, 62.5 mm <br /> <br /> A notable conid for producing perhaps the most 'cone'-like shell of all cone snails, the "Adam's Cone" typically exhibits a carinated shoulder combined with a low spire and straight sides. In extreme cases, the spire is even sunken. The base colouration is whitish and ornamented with a few spiral striation at the most anterior part; the colour pattern consists of numerous reddish-brown speckles often forming two broad bands. The amount and darkness of the colour pattern vary greatly across specimens, larger specimens are typically paler. An uncommon species, it lives in moderate depths between about 80~150 m deep from the Gulf of Carpentaria off Northern Australia to the Arafura Sea. Typical shell length around 60 mm, very large specimens can reach 100 mm. It is often placed in the genus or subgenus Plicaustraconus. <br /> <br /> When looking across a large series of specimens, it is actually quite variable in shell form in terms of spire height and shoulder carination. These atypical specimens appear to intergrade with the shallow water species Conus trigonus Reeve, 1848 inhabiting soft substrates from intertidal waters down to about -60 m of northern and northwestern Australia. Usually C. trigonus has a less carinated sholder with higher spire so the shell form is much less extreme than C. adami, but it is also a rather variable species. As such, there is some debate on whether these two should be treated as separate species, subspecies under the same species, or just two forms of the same species. Here they are treated as distinct pending further evidence.
Gloripallium speciosum (Reeve, 1853)<br /> PECTINIDAE<br /> -40~50 m, SCUBA dived under dead coral, Seragaki, Okinawa Island, Japan, 44.0 mm <br /> <br /> An intricately sculptured scallop characterised by broad ribs covered in large, raised scales, the "Specious Scallop" is rather widely distributed in the western Pacific with a range from southern Japan to Indonesia to Northwestern Australia. Extremely variable in colouration and patterning, but the sculpture is usually consistent though in most specimens the scales are eroded away. A rather common filter-feeding species living in moderately shallow water in coral reefs around the depth of -10~50 m, most specimens have been collected by divers in Okinawa, Japan despite its wider range. Specimens carrying one or few ribs with drastically different colouration to other ribs and the rest of the valve are termed 'rayed' and highly prized by collectors. Average shell length around 50 mm, very large specimens may exceed 65 mm. <br /> <br /> It is somewhat similar to Gloripallium pallium (Linnaeus, 1758) from the same region but it has undivided scales on ribs as opposed to divided to 2~3 in G. pallium. It can also be confused with the rare Gloripallium spiniferum (Sowerby I, 1835) from Polynesia but G. spiniferum has less ribs (around 7) than G. speciosum (around 11).
Coluzea juliae Harasewych, 1989<br /> COLUMBARIIDAE<br /> -300~500 m, Trawled, Off southern Mozambique, 74.3 mm <br /> <br /> Ranging from Mozambique to the southeastern part of mainland Africa, the "Julia's Pagoda" is an elegantly sculptured columbariid characterised by a sharp peripheral keel bearing long, narrow, anterior-directed spines with two to three further smooth spiral cords to either side. A carnivorous and predatory gastropod specialising on polychaete worms like other columbariids, it inhabits soft bottoms of rather deep waters between depth of about 300~700 m. An uncommon species, most specimens have been collected as trawl by-catches off Mozambique. Typical shell length around 70 mm, very large specimens are known to reach 90 mm. <br /> <br /> It is rather variable in shell sculpture, particularly the strength of spiral cords, ranging from very weak and narrow to very thick and broad. The weakly sculptured forms can be easily confused with the congener Coluzea eastwoodae (Kilburn, 1971) with which it shares both geographic and bathymetric ranges, but can usually be distinguished by the lack of raised spiral cords between suture and periphery in C. eastwoodae. Nevertheless, some specimens that appear to be intergrades between the two species exist and the relationship between these two species require further research. Another similar species is the extremely rare Coluzea liriope Harasewych, 1986 from Indonesia, but can be distinguished in that C. liriope has a less slender shell with the peripheral keel bearing blunt nodules instead of sharp spines.
Lepetodrilus marianae Chen, Watanabe & Tsuda in SOSA et al., 2024 <br /> LEPETODRILIDAE<br /> Holotype (SMF 373150)<br /> -1660 m, Northwest Eifuku Volcano hydrothermal vent field (21°29.2506'N, 144°02.4498'E), By suction sampler, ROV KM-ROV dive #223, R/V KAIMEI cruise KM23-05, 2023/iii/25, 8.3 mm <br /> <br /> A vetigastropod limpet endemic to deep-sea hydrothermal vents, Lepetodrilus marianae is distributed across many vent fields of Mariana Arc and Mariana Trough in the western Pacific between about 1500~4000 m deep. Though it has been recognised as a new species first by the late German malacologist Lothar A. Beck (1954-2020) as early as the 1990's and supported by genetic data since 2008, it remained unnamed until 2024 partly due to genus Lepetodrilus being a taxonomically difficult group with many cryptic species. Close investigation revealed that it actually combines two types of concentric shell sculpture -- a very fine type evident across growth stages and a broad, irregular, strongly raised type only appearing in large adults -- that differentiates it from all other congeners. These sculptures together generate a unique 'wrinkled' shell among Lepetodrilus species. <br /> <br /> The specific epithet 'marianae' was first proposed by Beck and his former student Kathrin Sobjinski in the late 1990's, which was kept for the formal description. Though the specific feeding ecology is not known for this species, Lepetodrilus species are known to combine grazing on bacterial films and filter-feeding using the gill, and this species probably does the same. At vents it forms very dense aggregations on sulfide chimney structures, mussel shells, and other substrates, and is one of the most abundant species. However, due to the very restricted area of such vent fields, it remains a very difficult species to collect and has only been sampled during expeditions using scientific submersibles. Typical shell length around 5 mm, the largest known specimens attain 8.5 mm.
Shinkailepas gigas Chen, Watanabe & Tsuda in SOSA et al., 2024 <br /> PHENACOLEPADIDAE<br /> Holotype (SMF 373153), male<br /> -1615 m, Northwest Eifuku Volcano hydrothermal vent field (21°29.2383'N, 144°02.4937'E), By suction sampler, ROV KM-ROV dive #213, R/V KAIMEI cruise KM23-05, 2023/iii/07, 23.0 mm <br /> <br /> With a shell length averaging around 20 mm and known to reach 23 mm, Shinkailepas gigas is currently the largest species in genus Shinkailepas -- and hence the name. Like other congeners it is endemic to deep-sea hydrothermal vent fields, and is a western Pacific species currently known from two vents on the Mariana Arc and one in the Manus Basin between depths of about 500~1600 m. It is thought to feed on bacteria growing on sulfide chimneys and other hard structures by grazing. In its local habitat it is an uncommon species that form small aggregations in very specific, suitable micro-environments, typically on whitish bacterial mats around low-temperature 'diffuse flow' venting orifices. <br /> <br /> Only a small number of individuals have been collected by research submersibles, with all specimens housed in research institutes or museums. The finely cancellate sculpture where concentric ribs are stronger than radial ones, the very posterior-situated apex protruding beyond shell edge, and the very large size together serve to distinguish this species from other Shinkailepas species. The only other described congener reaching a similar size is S. conspira Beck in Chen & Sigwart, 2023, but that species clearly differs morphologically by having a more anterior, central apex.
Bursa humilis Beu, 1981<br /> BURSIDAE<br /> -242 m, Taken by ROV, Southwest of Augusta, Western Australia, Australia, Leg. & Ex-coll. Ray Walker, 38.2 mm <br /> <br /> Endemic to southwestern Australia from South Australian Bight to the western coast, Bursa humilis is a small bursid characterised by a uniform nudular sculpture, relatively short spire, very short siphonal canal, and bright blood-red parietal colour patches. Inhabiting sandy bottoms of moderate depths around 100~400 m deep, it is thought to be a carnivorous and predatory gastropod feeding on polychaete worms like other bursids. A rather rare species partly due to the habitat depth, it was usually taken by dredging or by crab traps but recently some specimens have also been collected by ROVs. <br /> <br /> It is a very little-varied species, with quite consistent sculpture across specimens. Typical shell length around 35 mm, very large specimens can reach 45 mm. Originally described as a subspecies of the widespread Tritonoranella ranelloides (Reeve, 1844), it is currently considered to be a separate species. The two can be differentiated by B. humilis having much more compressed shells with a shorter spire, much shorter and more twisted anterior siphonal canal, and different sizes and distributions of the nodules between varices.
Cymbiola pulchra excelsior Bail & Limpus, 1998 <br /> VOLUTIDAE<br /> -5~10 m, Dredged on coarse coral sand, Departure Reef, Swain Reefs, Great Barrier Reef, Queensland, Australia, 2001, 49.3 mm <br /> <br /> Endemic to Departure Reef in the northern part of Swain Reefs complex, Great Barrier Reef off Queensland, Australia, Cymbiola pulchra excelsior is one of many local subspecies and forms of C. pulchra, the “Beautiful Volute”. The C. pulchra species complex is distributed across coral reefs from Queensland to northern New South Wales, with different localities hosting morphologically distinct morphs. Some of these have been raised to full species, such as C. cracenta (McMichael, 1963), while others such as C. p. excelsior have remained as subspecies or even forms. Cymbiola species, as is typical for volutids, are direct developers that lack long larval dispersal; meaning each population is prone to genetic isolation. At what taxonomic rank each population should be treated is much debated and warrants future research combining both anatomical and molecular data. It is in subgenus Cymbiolacca, which some consider to be a full genus. <br /> <br /> Cymbiola p. excelsior is distinguished from other members of the C. pulchra complex by its characteristic shell pattern, where hundreds of tiny triangular brown speckles align to form intricate tent-like patterns. With an average shell length around 50 mm and very large specimens reaching 70 mm, it is also among the smaller taxa in the C. pulchra complex. Like other members of the complex, Cymbiola p. excelsior lives on sand and coral rubble bottoms in shallow waters down to about 30 m deep. It is thought to be a carnivorous and predatory gastropod feeding on invertebrate animals like other volute snails. Although only uncommon in its natural habitat, it is a rarity in collections due to its distribution range being restricted to a very remote reef which is now proctected. Most specimens have been collected during dedicated diving and dredging expeditions to sample the remote parts of the Great Barrier Reef.
Cymbiola pulchra coucomorum Bail & Limpus, 1998<br /> VOLUTIDAE<br /> Dredged, Elusive Reef, Swain Reefs, Great Barrier Reef, Queensland, Australia, 73.6 mm <br /> <br /> Endemic to the easternmost Elusive Reef in the Swain Reefs complex of the Great Barrier Reef off Queensland, Australia, Cymbiola pulchra coucomorum is one of many local subspecies and forms of C. pulchra, the “Beautiful Volute”. The C. pulchra species complex is distributed across coral reefs from Queensland to northern New South Wales, with different localities hosting morphologically distinct morphs. Some of these have been raised to full species, such as C. cracenta (McMichael, 1963), while others such as C. p. coucomorum have remained as subspecies or even forms. Cymbiola species, as is typical for volutids, are direct developers that lack long larval dispersal; meaning each population is prone to genetic isolation. At what taxonomic rank each population should be treated is much debated and warrants future research combining both anatomical and molecular data. It is in subgenus Cymbiolacca, which some consider to be a full genus. <br /> <br /> Cymbiola p. coucomorum is distinguished from other members of the C. pulchra complex by its narrow shell ornamented with large and rather regular tent-like pattern, and further peppered with black spots. Most specimens also exhibit two broad reddish bands, though this feature can be lacking. With an average shell length around 70 mm and very large specimens reaching 90 mm, it is also among the larger taxa in the C. pulchra complex. Like other members of the complex, Cymbiola p. coucomorum lives on sand and coral rubble bottoms in shallow waters down to about 30 m deep. It is thought to be a carnivorous and predatory gastropod feeding on invertebrate animals like other volute snails. Although only uncommon in its natural habitat, it is a rarity in collections due to its distribution range being restricted to a now-protected very remote reef. Most specimens have been collected during dedicated diving and dredging expeditions to sample the remote parts of the Great Barrier Reef. It was named in honour of the Australian conchologists Cedric and Ena Coucom of Yeppoon, Queensland.
Buccinum felis Okutani, 1964<br /> BUCCINIDAE<br /> -350~400 m, In crab pot, Tokyo Bay, Off Kenzaki, Kanagawa Prefecture, Japan, 2007, 37.6 mm <br /> <br /> An instantly recognisable species among cold-water buccinids of the northwestern Pacific due to its small size and a patterned shell marked by reddish brown dots and irregular patches, Buccinum felis is endemic to northern Japan ranging from Hachijō Island to Mie Prefecture to the Tōhoku Region. A carnivorous and predatory gastropod feeding on invertebrate animals, it inhabits sandy bottoms between 200~600 m deep and is typically collected by whelk or crab pots and traps. It has always been an uncommon species, and in the recent years it has increased in scarcity; it is now very difficult to obtain live-taken specimens. Typical shell length around 35 mm, very large specimens may reach 45 mm. <br /> <br /> The shell form is remarkably uniform across specimens, but the same cannot be said of the colour pattern and sculpture. The distribution and extent of the colour blotches vary greatly among individuals, some are nearly entirely pale while others can be almost fully covered by brown patches and thus very dark. The sculpture consists of numerous spiral cords and threads that are typically much stronger on the earlier whorls, but differ greatly among individuals to range from nearly smooth to strongly corded. The name shikamai Habe & Ito, 1965 was given to specimens with numerous raised spiral threads and clear brown patches on the body whorl, though described as a subspecies of B. felis, it is now considered to be a junior synonym and merely a form. Another potentially synoymous name is B. hosoyai Habe & Ito, 1965, which is identical in every way to B. felis except the body whorl carries a few strong spiral cords instead of weak spiral threads. The known range of all three names also overlap. The names shikamai and hosoyai were dedicated to the Japanese paleontologist Tokio Shikama (1912-1978) and conchologist Kakujiro Hosoya (1884-1956), respectively.
Conus nocturnus [Lightfoot], 1786 <br /> CONIDAE<br /> -20 m, Dived, Off Manado, North Sulawesi, Indonesia, 2023/vii, 60.5 mm <br /> <br /> Characterised by a pattern with two very broad and dark bands separating zones of irregular white tent-like patterns, the "Nocturne Cone" is a conid endemic to Indonesia. Only known from the eastern part of the country approximately between Sulawesi Island and western New Guinea, it lives in shallow waters between about 1 to 30 m deep on coral sand and rubble. The type locality was originally stated as "China", which is now considered erroneous. This has caused the species to become 'lost' for about two centuries before it was finally rediscovered in Indonesia. Partly due to this convoluted history it was considered a classic rarity for decades, but recently there has been a surge in shell collecting activities in Indonesia leading to an increased availability, rendering it uncommon at most. A carnivorous gastropod, it is an active predator feeding on other molluscs. <br /> <br /> The overall shell form and pattern varies only slightly, most notably in the size and extent of the white 'tents'. Vast majority of specimens exhibit very dark brown and close to solid black bands, but rarely shells with lighter brown bands are also found. Like many conid species, the shell surface can be either smooth or strongly granulose; the latter form has been named f. deburghiae Sowerby II, 1857. Some specimens have been found to transition from smooth to granulate or vice versa through growth. Typical shell length around 60 mm, very large specimens can exceed 85 mm. <br /> <br /> It is most similar to Conus bandanus Hwass, 1792, which can be distinguished by a more conical body whorl with straight sides, more of the shell surface being covered by white tent-like pattern, and growing to a larger size (reaching 150 mm). Though C. bandanus is very variable and some forms such as C. bandanus f. equestris Röding, 1798 are smaller with less tenting, the conical shell form with straight sides can always differentiate it from C. nocturnus.
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