Skip to content
Dr. Chong CHEN

Dr. Chong CHEN

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

  • Home
  • Research Interests
  • Publications
    • Browse Publications
  • Curriculum Vitae
  • Full CV [PDF]
  • Expeditions
    • Expedition Gallery
  • The C. Chen Collection
  • Google Scholar
  • Researchmap
  • ResearchGate
  • ORCID
  • Contact
  • Facebook
  • Twitter
  • ResearchGate
  • GoogleScholar

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.

Pandora pulchella Yokoyama, 1926 <br /> PANDORIDAE<br /> -250~350m, On mud bottom, By tangle nets, Off eastern South Korea, 47.5mm, F/F+<br /> Pandora pulchella is a pandorid ranging from Sea of Japan to Russia with intriguing form and sculpture; it can be distinguished from other pandorids in the region by the strongly recurved shape and large size. It is in fact better known from Cenozonic fossils which are practically identical to the recent specimens, and was originally described from such fossils originating from oil-fields in Akita Prefecture, Japan. Unlike the fossils which are relatively common in especially in Japan, recent specimens (particularly live-taken ones) appear to be very scarce. A burrowing bivalve, in life it positions itself with the convex left valve down inside muddy substrates, and is a filter-feeder inhabiting rather deep water around -100~400m. It is often placed in the subgenus Heteroclidus, which many authors consider to be a full genus. Typical shell length around 45mm, very large specimens may exceed 55mm.
Scaphella dohrni (Sowerby III, 1903) <br /> VOLUTIDAE<br /> Gulf of Mexico, 55.1mm, F/F+, Ex-coll. Carol Brunner<br /> The "Dohrn's Volute" is an attractively patterned volute with about eight rows of almost equally spaced dark square patches on the body whorl. Ranging from eastern Florida to Gulf of Mexico to southern Cuba, it is a carnivorous and predatory gastropod inhabiting sandy bottoms of rather deep water around -100~500m. An uncommon species, it is usually dredged dead and prone to growth scars; live-taken specimens in good quality are rare. The early whorls may be shouldered, bearing a single row of closely spaced nodules. Typical shell length around 70mm, very large specimens may exceed 130mm.
Scutellastra cochlear (Born, 1778) <br /> PATELLIDAE<br /> Low tide, On rocks, Port Elizabeth, Eastern Cape, South Africa, 48.5mm, F+<br /> The "Pear Limpet" (or "Spoon Limpet") is a patellid ranging from river mouth of the Orange River and across the Cape Province to Durban, South Africa; aptly named for its very distinctive shape resembling a pear. It is a locally abundant species forming prominent dense colonies on the eulittoral zone of rocky shores, preferring exposed shores with strong wave motion. A herbivorous gastropod, each individual establishes a limpet scar on the rock and occupies the same position throughout the life; juveniles commonly establish on the shells of adult limpets until they are large enough to establish their own limpet scar. It primarily feeds on the coralline algae Spongites yendoi (Foslie) Chamberlain, 1993 and individuals are known to farm S. yendoi in algae gardens around the limpet scar, and protect these gardens territorially. The limpet-algae relationship may be mutualistic as S. cochlear excludes other alga species from the shore in favour of S. yendoi and the limpet excretions provide additional nitrogen for the algae, increasing its productivity. Exterior of the shell bears radial ribs but is often strongly encrusted, the interior is white with a varying strength of blue, the muscle scar is black. Typical shell length around 50mm, very large specimens may exceed 70mm.
Spondylus tenellus Reeve, 1856 <br /> SPONDYLIDAE<br /> -80~200m, Trawled from sand/mud bottom, Off Lakes Entrance, Gippsland, Victoria, Australia, 63.6mm, F++, 1986<br /> The "Scarlet Thorny Oyster" is a lovely spondylid endemic to Australia, widely ranging across the entire southern coast from Jurien Bay, Western Australia to southern Queensland, including Tasmania. A sessile filter-feeding bivalve living attached to hard substrates, it is found in subtidal and offshore waters of moderate depths around -20~80m and often inhabits rock crevices. Like many spondylids it is a very variable species in spine development, shell form, and colouration: from white to pink to orange to wine red. Typical shell length around 70mm, very large specimens may exceed 110mm. An uncommon species, it takes some luck to find a high-quality specimen with long spines.
Cymatium femorale (Linnaeus, 1758) <br /> RANELLIDAE<br /> -3~6m, Dived, La Tortuga Island, Venezuela, 117.4mm, F+, 2013<br /> The "Angular Triton" is a handsome ranellid instantly recognisable by its strongly raised shoulder. It is native to the Caribbean Sea and adjacent waters, ranging from southern Florida, USA to Brazil. A carnivorous and predatory gastropod primarily feeding on echinoderms, it typically inhabits shallow water from extreme low-tide down to about -50m and is locally common. Typical shell length around 120mm, very large specimens may exceed 170mm. Its range partly overlaps with the closely related Cymatium raderi D'Attilio & Myers, 1984 and is often confused with it. The two are in fact easily separable, however, as C. raderi is much larger on average (commonly exceeds 200mm which C. femorale never reaches) and the varices of C. raderi are much more smooth and less angulate, lacking in strong protuberances seen on the varices of C. femorale.
Cymatium ranzanii (Bianconi, 1850) <br /> RANELLIDAE<br /> -12m (-40 ft), Somalia, 160.2mm, F++, 1975<br /> The "Ranzani's Triton" is a famous rarity among the ranellids and one of S. Peter Dance's fifty Rare Shells (1969). Although described in 1850, it has a remarkable history of being "lost" for more than a century in literature until re-discovered by K. J. Grosch when diving in Mozambique in 1953. The remarks on Grosch's find was published by William K. Emerson and Anthony D'Attilio, who identified the species, in 1962. The angular but low shoulder and two distinct dark patches on the parietal callus together separates it from other Cymatium species without difficulty. A carnivorous and predatory gastropod, it inhabits shallow water to about -40m depth and ranges from Northern Arabian Sea to Mozambique including Southern Red Sea. It appears to be most common in Somalia where vast majority of specimens originate, and is still moderately rare today as a result from the difficulty in obtaining material from the area due to piracy and political instability. The average shell length is about 160mm, but giants are known to exceed 240mm.
Septa marerubrum (Garcia-Talavera, 1985) <br /> RANELLIDAE<br /> -15m, Dived, Sinai Peninsula, Egypt, 38.0mm, F++<br /> The "Red Sea Triton" is a striking ranellid endemic to the Red Sea. Originally described as a full species but in the earlier years many considered it to be a Red Sea subspecies of the certainly closely related Septa rubecula (Linnaeus, 1758); today it is generally accepted as a full species. Although indeed similar to S. rubecula, S. marerubrum can be easily distinguished from the more coarse sculpture as it has wider and taller spiral cords bearing much more irregular and larger gemmae. General form of the shell is very variable though the sculpture less so. A carnivorous and predatory gastropod, it inhabits very shallow water from low tide down to about -20m deep. Typical shell length around 35mm, very large specimens may reach 50mm. Though uncommon on the shell trade market due to its restricted distribution, it is locally a common species in its natural habitat.
Biplex perca Perry, 1811 <br /> RANELLIDAE<br /> -350m, Trawled from sand/gravel/mud bottom, East China Sea, Off Zhejiang, China, 83.5mm, F++, 2014<br /> The "Maple Leaf Triton" is a most eccentric ranellid widely dirstributed across the Western Pacific region, from Japan to northern Australia and across the central Western Pacific islands. It is replaced by its sister species Biplex bozzettii Beu, 1998 with a consistently wider shell from southern India and westward into the Indian Ocean. A common carnivorous species, it is mostly found on sandy to gravely bottoms around -50~200m deep although occasionally deeper. The shell is much compressed in the dorsal-ventral direction and has regular wing-like varices every 180 degrees, resulting in a flat and wide leaf-like shell; aptly described as "maple leaf" in the English vernacular name. The varices are fragile and prone to damage, it is difficult to find a large specimen with intact varices. The intervarical space carry beaded sculpture but the beading is normally not consistent throughout, unlike B. bozzettii. Typical shell length around 65mm but it is very variable in size and giant specimens may reach even 100mm.
Bayerotrochus westralis (Whitehead, 1987) <br /> PLEUROTOMARIIDAE<br /> -600~1000m, Trawled on sand and mud, Off Rowley Shoals, Western Australia, Australia, 103.2mm, F+, 1983<br /> The "Western Australian Slit Shell" is a pearly pleurotomariid best known from the northern half of Western Australia, Australia where vast majority of specimens originate from. Its definitive range extends northwards to the Ashmore and Cartier Islands, although there are records from as far north as southern Japan. The shell surface has a characteristic iridescent pearly sheen, and is usually pale white to yellowish brown and decorated with occasional axial flammules. Young specimens often have a strongly angulate body whorl. Dark coloured specimens with dense orange flammules are also occasionally found. The slit is typical of the genus Bayerotrochus: short but rather wide and occupying around one-fifth of the circumference of the body whorl. An uncommon species, it is a carnivorous grazer primarily feeding on sponges and inhabit sandy to muddy bottoms of quite deep water around -300~1000m, averaging around -500m. Typical shell length around 85mm, very large specimens are known to exceed 130mm.
Chicomurex globus Houart Moe & Chen, 2015<br /> MURICIDAE<br /> -200m, By tangle nets, Surigao Straits, Mindanao, Philippines, 35.7mm, F++, PARATYPE<br /> Chicomurex globus is a medium sized Chicomurex ranging from Okinawa, Japan to Philippines to Vanuatu and New Caledonia. Named for its rounded outline, it has long been confused with C. gloriosus (Shikama, 1977) [C. gloriosus is the species often referred to s 'C. venustulus' from Philippines and elsewhere, the true C. venustulus (Rehder & Wilson, 1975) is restricted to the Marquesas]. It differs from C. gloriosus by the globous shape resulting from broader shell with shorter siphonal canal, more shouldered and smaller shell; it also has a very distinctive dorsally recurved spine on the siphonal canal. The shell is variable in colouration, from cream to tan to white. Often carry dark blotches, and may be banded like C. gloriosus. Presumably a carnivorous species like other congeners, it inhabits moderate depths around -20~200m. Typical shell length around 40mm, very large specimens may reach 53mm.
Mikadotrochus gotoi (Anseeuw, 1990) <br /> PLEUROTOMARIIDAE<br /> -200m, By tangle net, Taguin, Balut Island, Davao Occidental, Philippines, 44.5mm, F++<br /> The "Goto's Slit Shell" is a lovely and gemmate western Pacific pleurotomariid ranging from Amami Islands, Japan to Philippines. A carnivorous grazer feeding mainly on sponges, it inhabits hard substrates of rather deep water around -150~400m. Vast majority of specimens are less than 50mm in shell length, averaging at about 45mm. In the Philippines these young specimens are only uncommon, although large specimens in excess of 55mm are rare. Outside the Philippines it is a rare species in any size, although this is likely due to lack of tangle net deployments. Extremely large specimens may exceed 65mm. Young specimens have strongly keeled whorls, while large specimens have noticeably more inflated and round whorls. Always has alternating reddish and white patches under the selenizone, although the overall colouration may vary slightly. It is named in honour of Mr Yoshihiro Goto of Japan, an enthusiastic conchologist with a speial interest in the Pleurotomariidae in which he named several new species, for example Perotrochus anseeuwi Kanazawa & Goto, 1991 and P. metivieri Anseeuw & Goto, 1995.
Simnia patula (Pennant, 1777) <br /> OVULIDAE<br /> -50m, Trawled, Off Devon, Southwest England, United Kingdom, 25.4mm, F++<br /> The "Poached Egg Shell" is a beautiful and frail ovulid ranging from Norway to Canary Islands, and into the Mediterranean Sea. A carnivore and ectoparasite of octocorals and hydroids, it lives in moderately deep sublittoral water around -20~120m. Its most common hosts are the soft coral Alcyonium digitatum L., 1758 ("Dead Man's Fingers"), the sea fan Eunicella verrucosa (Pallas, 1766), and the hydroid Tubularia indivisa L., 1758. The shell is variable in colouration from white to cream to dark orange as well as shape of the extremities, while the mantle is decorated with brown streaks and spots. Although a common species in its natural environment, it is an uncommon to rather rare species on the shell trade especially in good condition. Typical shell length around 20mm, very large specimens like the one shown may exceed 25mm. Its type locality is Weymouth, Dorset, England.
Arrhoges occidentalis (Beck, 1836) <br /> APORRHAIDAE<br /> -100m, Trawled, Off Chebucto Head, Nova Scotia, Canada, 53.0mm, F+<br /> The "American Pelicanfoot" is graceful aporrhaid and the only extant species native to the western Atlantic, ranging from Greenland to Nova Scotia, Canada to North Carolina, USA. It is also the only extant species in the genus Arrhoges, although many do not consider this a full genus and still place it in Aporrhais. Compared to the other living aporrhaids its outer lip is simple with only a single projection, while others have multiple spines. It is a herbivorous and detritivorous species feeding on microalgae and detritus, and inhabits sandy to muddy bottoms of a rather wide bathymetric range around -10~400m deep. It is a rather rare species in the shell trade, especially live collected specimens of good quality as it is usually a rough shell; most specimens are trawled off Atlantic Canada. It is very variable in spire height; specimens with slender spire bearing relatively few axial ridges has been described as f. mainensis (Johnson, 1930), while those with very high spire has been named f. labradorensis (Johnson, 1930). Typical shell length around 50mm, very large specimens may exceed 65mm.
Beringius turtoni (Bean, 1834) <br /> BUCCINIDAE<br /> -150m, Flanden Ground, North Sea, Scotland, United Kingdom, 127.8mm. F++<br /> The "Turton's Whelk" is a large and elegant circum-arctic cold-water buccinid best known from North Sea off Yorkshire, United Kingdom to the west coast of Norway. It was first discovered and described by William Bean, using material dredged from deep water off Dogger Bank, North Sea. It is named after a British conchologist of the time, William Turton. A carnivorous / scavenging gastropod, it inhabits rocky to muddy bottoms of moderately deep water around -20~250m. It is a rather rare species, especially in large and good condition like the specimen shown; as most specimens have obvious growth scars, apex knocked off, or have lost the periostracum. Although the sculpture is quite consistent, the shell form varies greatly; especially in terms of the shell breadth to height ratio. Typical shell length around 110mm, very large specimens may exceed 140mm. Beringius ossiania (Friele, 1879) is currently considered a junior synonym.
Septa closeli (Beu, 1987) <br /> RANELLIDAE<br /> -3~5m, By SCUBA diver, Nacala Bay, Mozambique, 47.8mm, F++<br /> The "Closel's Triton" is a rather dusky coloured Septa species endemic to the Indian Ocean, ranging from Sri Lanka to South Africa. It is the most common Septa species in Indian Ocean where other members of the genus are rare. Presumably carnivorous like other ranellids, it inhabits very shallow to moderate depths from lowtide zone down to about -20m in the coral reefs. Very similar to the closely related S. hepatica (Röding, 1798), which it was initially considered a variety of. It is differentiated from S. hepatica by its darker varices without distinct stripes and more dissolved, less distinct dark bands between spiral cords. The overall colouration however is quite variable from cream to dark brown, though is on average darker and less vivid than S. hepatica. A layer of hairy periostracum covers the shell when alive. A large Septa species, very large specimens may exceed 60mm although most specimens average at around 45mm.
Septa bibbeyi (Beu, 1987) <br /> RANELLIDAE<br /> -10~15m, Olango Island, Central Visayas, Philippines, 39.1mm, F++<br /> The "Bibbey's Triton" is an intensely crimson ranellid that appears to be endmic to the Philippines. A rather common carnivorous gastropod, it inhabits moderately shallow water in reefs around -10~30m deep. When alive it is covered by a layer of hairy periostracum as is typical in Ranellidae. Although similar to the closely related S. rubecula (Linnaeus, 1758) which it was initially confused, it has a more inflated and more coarsely beaded body whorl with a much longer anterior siphonal canal. In addition the white spiral band and the adjoining white patch on varices always cover two spiral ribs or more, which is wider than that of a typical S. rubecula. A medium-sized Septa, the typical shell length is around 40mm although giant specimens may exceed 50mm. It is named after Loyal J. Bibbey who first noticed its distinctiveness from S. rubecula.
Septa hepatica (Röding, 1798) <br /> RANELLIDAE<br /> -20~25m, Eastern Samar, Samar Island, Eastern Visayas, Philippines, 44.8mm, F+<br /> The "Black Striped Triton" is a strikingly coloured ranellid very widely distributed throughout the Indo-West Pacific region. A common carnivorous gastropod, it inhabits shallow to moderate depths of around -10~40m in the reefs. The signature black colouration in the interspaces of spiral ribs always present throughout to the body whorl, but the background colouration vary from cream to red. Although in the closely related species S. rubecula (L., 1758) the black intercord characteristic is also sometimes present, S. rubecula always has a pronounced white patch on the upper part of each varix and can be easily distinguished. A thick hairy periostracum conceals the brilliant colouration when the animal is alive, making it surprisingly difficult to locate. It is the second largest Septa species, with giant specimens exceeding 65mm. Typical specimens however averages at around 45mm. It is renowned as one of the "Three Beautious Snails" in Japan, along with S. rubecula and S. flaveola (Röding, 1798).
Septa flaveola (Röding, 1798) <br /> RANELLIDAE<br /> -25m, Olango Island, Central Visayas, Philippines, 43.1mm, F+<br /> The "Golden Triton" is a beautiful ranellid widely distributed in the Indo-Pacific, best known from the Philippines. It is moderately common in the Philippines but uncommon in the rest of Western Pacific, and very rare in the Indian Ocean. A carnivorous gastropod, it inhabits rocky surfaces and among coral rubbles in the reefs of moderate depths around -10~50m. The live animal carry a rather thick layer of bristly periostracum, characteristic of the family Ranellidae. It is probably the largest species in genus Septa with gigantic specimens reaching 80mm, although vast majority averages at around 45mm. It is a renowned species in Japan where it is known as one of the "Three Beautious Snails", along with congeners S. rubecula (Linnaeus, 1758) and S. hepatica (Röding, 1798).
Septa rubecula (Linnaeus, 1758)<br /> RANELLIDAE<br /> -10~15m, Dived, Bohol Island, Central Visayas, Philippines, 43.8mm, F++, 2012<br /> The "Robin Redbreast Triton" is a common but lovely ranellid with a very wide distribution throughout the Indo-West Pacific region. A carnivorous gastropod like other Septa species, it lives beneath or among corals of the reefs in shallow to moderate depths of around -5~30m. When alive the brilliant intense red colour is hidden under a layer of bristly periostracum, rather thick and chestnut yellow in colour. There is usually a diffused white band around the fifth spiral cord. Typical shell length around 40mm, very large specimens may exceed 55mm. It is similar to a number of other Septa species such as S. bibbeyi (Beu, 1987) and S. hepatica (Röding, 1798), and is sometimes confused with them. In Japan it is reknowned as one of the "Three Beautious Snails", along with S. flaveola (Röding, 1798) and S. hepatica.
Septa mixta (Arthur & Garcia-Talavera, 1990) <br /> RANELLIDAE<br /> Philippines, From old collection, 32.3mm, F++<br /> Septa mixta is perhaps the most enigmatic species of the ranellid genus Septa. Due to its superficial similarity to the closely related S. rubecula (Linnaeus, 1758) and S. occidentalis (Mörch, 1877) it has been much confused with them (hence 'mixta'). Compared to S. rubecula it has 1. an absolutely sharp and crisp white band covering the entire length of the fifth (and only the fifth) spiral cord; this band is usually more diffused and spread out to intercord space and adjascent spiral cords in S. rubeculum (sharp band similar to S. mixta is not unknown but rare). 2. The spiral cords are much stronger with larger beads and more coarsely sculptured dorsum. 3. The form is more angulate in appearance. Compared to S. occidentalis, S. mixta's dorsum is less scabrous in sculpture and there is usually only one strong intervarice node; the very sharp white band is often still a good indicator. Widely distributed from the northern Indian Ocean to New Caledonia, it is presumably a carnivorous gastropod like its congeners and inhabits moderate depths around -20~50m. Many specimens identified as S. mixta are misidentified S. rubecula, and true specimens of S. mixta appear to be very rare. Typical shell length around 30mm, very large specimens may exceed 45mm.
Chicomurex gloriosus (Shikama, 1977)<br /> MURICIDAE<br /> -100~200m, By tangle net, Tinina, Balut Island, Davao Occidental, Philippines, 51.5mm, F++, 2013/xi<br /> Chicomurex gloriosus is a medium sized Chicomurex ranging widely across the Indo-West Pacific region ranging from Reunion and Mauritius to Indonesia to Philippines to Japan to Papua New Guinea. It has been considered a junior synonym of C. venustulus (Rehder & Wilson, 1975) and confused with that species for a long time but recently after careful comparison with C. venustulus from the Marquesas, its type locality, a number of consistent and reliable features was found to differentiate them (Houart Moe & Chen, 2015). These include C. gloriosus being much larger, not as stocky, and has longer siphonal canal as well as higher intervarical nodes. Furthermore, C. gloriosus is much less scabrous and the two differ in positions of the coloured spiral bands when they are present. Houart Moe & Chen (2015) reinstated the name C. gloriosus, and the true C. veustulus is now considered to be endemic to the Marquesas. It is a common carnivorous gastropod inhabiting moderately deep water around -50~200m, and is very variable in colouration from cream to pink to red to brown. Darker coloured spiral band often present. Typical shell length around 45mm, very large specimens may reach 60mm.
Chicomurex pseudosuperbus Houart Moe & Chen, 2015<br /> MURICIDAE<br /> -200m, Off Balut Island, Davao Occidental, Philippines, 64.5mm, F++, PARATYPE<br /> Chicomurex pseudosuperbus is a large Chicomurex ranging from Okinawa, Japan to Philippines to New Caledonia and Queensland, Australia. Majority of specimens have come from the central Philippines where it is common, outside Philippines it is uncommon to moderately rare. It was named pseudosuperbus because it has been misidentified as C. superbus in the recent literature. It has been confused with C. lani Houart Moe Chen, 2014 [which was thought to be C. superbus (Sowerby III, 1889) until the rediscovery of its holotype, C. superbus is now a senior synomym of C. problematicus (Lan, 1981)] but has a larger shell, more adressed suture, longer siphonal canal, more obvious axial nodes, and a more scabrous shell. It differs from the true C. superbus by having a narrower, higher spired shell with narrower secondary cords; also importantly the spiral cords are not as clearly overlaid with brown line as in C. superbus. It is presumably a carnivorous gastropod like other Chicomurex and inhabits moderate depths around -60~200m. Typical shell length around 65mm, very large specimens may reach 85mm.
Chicomurex globus Houart Moe & Chen, 2015<br /> MURICIDAE<br /> -150m, Trawled, Lipata, Surigao, Philippines, 39.5mm, F++, 2013 (specimen examined for description but not in the type series)<br /> Chicomurex globus is a medium sized Chicomurex ranging from Okinawa, Japan to Philippines to Vanuatu and New Caledonia. Named for its rounded outline, it has long been confused with C. gloriosus (Shikama, 1977) [C. gloriosus is the species often referred to s 'C. venustulus' from Philippines and elsewhere, the true C. venustulus (Rehder & Wilson, 1975) is restricted to the Marquesas]. It differs from C. gloriosus by the globous shape resulting from broader shell with shorter siphonal canal, more shouldered and smaller shell; it also has a very distinctive dorsally recurved spine on the siphonal canal. The shell is variable in colouration, from cream to tan to white. Often carry dark blotches, and may be banded like C. gloriosus. Presumably a carnivorous species like other congeners, it inhabits moderate depths around -20~200m. Typical shell length around 40mm, very large specimens may reach 53mm.
Septifer bilocularis (Linnaeus, 1758) <br /> MYTILIDAE<br /> Low tide, Attached to rocks, South China Sea, China, 31.2mm, F++<br /> The "Ledge Mussel" is an abundant mytilid widely distributed in the Indo-Pacific, ranging from Japan to Australia to Red Sea. A filter-feeding species, it lives attached to hard substrates such as rock or dead coral using byssus threads in very shallow to shallow water ranging from intertidal zone to about -15m deep. Extremely variable in colouration and pattern, the colour may be anything from black to blue to green to red. The most stunning form is possibly the almost entirely bright blue form as shown, although this colour is by no means rare in this species. The shell form, especially the convexness, is variable too and influenced by environmental factors. Individuals subjected to strong wave action generally have more convex shells than individuals in sheltered areas. Typical shell length around 40mm, although extremely large specimens may exceed 65mm.
Provanna nassariaeformis Okutani, 1990 <br /> PROVANNIDAE<br /> -3500m+, Hydrothermal vent site, Mariana Trough, off Northern Mariana Islands, 11.5mm, F+<br /> Provanna nassariaeformis is a deep-sea provannid endemic to hydrothermal vents of the western Pacific Ocean. A detritus grazing gastropod, it is known from both Mariana Trough and Manus Back-Arc Basin where it inhabits great depths up to -3700m. The shell is very squat and wide for the genus, the white ostracum is covered by a golden brown periostracum which is usually further coated by a thick layer of hydrothermal deposits. The body whorl of adults carry about 20 axial ribs which crosses with four to five spiral ribs of similar strength, forming a cancellate and beaded sculpture. The apex is always corroded, leaving only two to three whorls in the adults. Typical shell length around 10-12mm, there appears to be little variation in size of adult specimens. Although it is only uncommon in the vent fields where it inhabits, the extreme depths make it very inaccessible and difficult to obtain.
Tenorioconus mappa ([Lightfoot], 1786) granarius (Kiener, 1847) <br /> CONIDAE<br /> -50m, North coast, Colombia, 46.4mm, F+, 1996/vi<br /> Tenorioconus granarius ranging from Panama to Venezuela is widely accepted as a subspecies of the beautiful Caribbean cone T. mappa; although sometimes considered a full species. It can be differentiated from other subspecies of T. mappa by its reduced colour patches, whitish grey to violet base colouration, high spire; and usually strong granulation as the name suggests. The deeper water specimens tend to have a taller spire (shown). It is a carnivorous and predatory vermivorous gastropod which mainly feeds on polychaete worms, such as fireworms (family Amphinomidae). A somewhat uncommon species, it inhabits sandy to muddy bottoms around -3~50m deep. Individuals aggregate to mate and spawn in the summer months of June to August, then depositing egg masses on hard substrates such as rocks or dead corals. Typical shell length around 50mm, extremely large specimens may exceed 70mm.
Bathybembix aeola (Watson, 1879) <br /> CALLIOTROPIDAE<br /> -450~550m, Trawled, Off Futaba-cho, Fukushima Prefecture, Japan, 41.2mm, F, 2013/iv<br /> The "Changing Margarite" is a beautiful 'trochid' now classified in Calliotropidae, best known from Japan where it ranges from Aomori Prefecture to the Kyushu Island but supposedly the distribution extends to East China Sea. A deposit feeding gastropod, it inhabits sandy to muddy bottoms of deep water around -300~1200m. It is known to have the ability of selectively ingesting fine particles, using the extraordinarily fine and long marginal teeth of its rhipidoglossate radula as a rake-like apparatus to filter out larger particles from ingestion. This is an effective and energetically efficient adaptation in deposit feeding as the gastropod digests the organic coating on grain surface, and finer grains have a larger surface area to volume ratio. Although only uncommon in Japan, but it is rarer and difficult to find in the international market. The shell carries a yellowish green periostracum, the apex is always corroded. Typical shell length around 40mm, very large specimens may exceed 50mm.
Pterynotus pellucidus (Reeve, 1845) <br /> MURICIDAE<br /> Off Sakai Harbour, Minabe-Cho, Wakayama Prefecture, Japan, 50.2mm, F+, 2011/iv<br /> The "Pellucid Murex" is a delicately winged muricid with a very wide range throghout the Indo-West Pacific, from east Africa to New Caledonia to southern Japan. The shell is white to pinkish, carries three varices on each whorl with lamellose ventral surface and scalloped edge. A carnivorous and predatory gastropod feeding on sessile animals, it inhabits rocky substrates in shallow to moderate depths around -10~100m deep. Although a common species, most adult specimens tend to have severely damaged varices and fine examples are uncommon. Typical shell length around 45mm, giant specimens may exceed 60mm.
Oenopota sagamiana Okutani & Fujikura, 1992 <br /> MANGELIIDAE<br /> -1170m, Methane seep site, Off Hatsushima Island, Sagami Bay, Kanagawa Prefecture, Japan, 20.1mm, F++<br /> Oenopota sagamiana is a peculiar mangeliid "turrid" endemic to a single deep-sea cold seep off Hatsushima, Sagami Bay, Japan. It is found in extremely dense aggregations on patches of bacterial mat and metachromatic seabed strongly influenced by methane seepage, around -1170m deep. Although Oenopota species have toxoglossate radula and are generally carnivorous / scavenging gastropods, it is uncertain what exact this species feeds on. Considering its strange habitat it probably feeds on microbial mat, but may also be preying on other seep fauna. The spindle-shaped shell is white and thick, carries about a dozen axial ribs (may form nodules on the shoulder) and is covered by a thin pale tan periostracum. Typical shell length around 20mm, there is little size variation among adults of this species and even very large specimens rarely exceed 25mm. It has been observed to travel in large groups, although details and intentions behind this behaviour is unknown.
Alcithoe tigrina Bail & Limpus, 2005 <br /> VOLUTIDAE<br /> -450m (-1500ft), Trawled by a prawn boat, Bay of Plenty, North Island, New Zealand, 118.1mm, F+, 1993/iii<br /> The "Tiger Volute" is an elegant volute endemic to the northeastern New Zealand, with a restricted range from Bay of Plenty to Cape Kidnappers. It is an uncommon species in Bay of Plenty, though is very rare south of it. A carnivorous and predatory gastropod inhabiting muddy bottoms, it is known from a rather wide bathymetric range from -100~600m. Typically uniformly cream or straw in colouration but sometimes has 'lightning' pattern composed of thin brown axial bands like the holotype, hence the name 'tigris'. Typical shell length 110mm, very large specimens may exceed 130mm. It was originally described as a subspecies of Alcithoe larochei Marwick, 1926, but as the range of two overlap (A. larochei ranges from northen South Island to North Island) they are now recognised as separate species. The two are quite similar but A. larochei is much broader, more solidly built and shouldered, and never carry the 'lightning' pattern.
Elliptio spinosa (Lea, 1836)<br /> UNIONIDAE<br /> Specimen in the collection of Ryan Hwang. Original photographs by Ryan Hwang, image processing and text written by Chong Chen.<br /> Altamaha River, At the U.S. Route 301 bridge, Doctortown, Long County, Georgia, U.S.A., 58.0mm, F+, 1963<br /> The "Altamaha Spinymussel" is a truly charismatic and enthralling freshwater pearl mussel famed for its distinctively robust and elongate spines. It is endemic to the Altamaha River and its tributaries in Georgia, U.S.A. and its type locality is the river's mouth near Darien. A filter-feeding bivalve, it seems to be limited to fast-flowing portions of the river and are often buried five to ten centimetres below the surface. Once ago before the mid-1900s it was a common species, but today like many other freshwater mussels its numbers have dwindled significantly due to habitat degradation and it has become very rare indeed. Also used to be more wide-spread with the range covering lower Ocmulgee, Oconee, and Ohoopee rivers, but none has been found outside the main Altamaha River since 2001. The largest number found in a single site since 1990 is only nine individuals and it is now limited to no more than five sites. In 2011 it was listed as an Endangered species in the USFWS under the Endangered Species Act of 1973 (althogh it has been listed as Endangered in Georgia before then), and also listed as Endangered in the IUCN Red List in 2012. Like other unionids it is known to go through a glochidia larval stage parasitising fish gills/fins, but it is yet unclear what its host fish species is (or are); making its conservation challenging as unionids often have specific hosts and it is necesary to conserve the host fish together with the mussel. Typical shell length around 70mm, very large specimens may exceed 110mm. The periostracum is shiny and greenish yellow in young specimens but becomes a very dark brown in gerontic specimens. The number of spines varies greatly, usually between one to five.
Scelidotoma gigas (Martens, 1881) <br /> FISSURELLIDAE<br /> -20~25m, Coast of Yagi, Hirono-cho, Iwate Prefecture, Japan, 82.3mm, F++, 2014/vii<br /> The "Giant Tugali Limpet" is a very large fissurellid native to northwest Pacific, with a distribution ranging from northern Korea and Japan (north of Fukushima Prefecture) to Sakhalin. A rather uncommon algae-grazing herbivorous species, it inhabits hard rocky substrates of intertidal to shallow subtidal waters down to about -30m deep. Although the shell is not colourful, its soft parts are vivid and brightly coloured in orange to red and the foot is larger than the shell. A shallow notch in the anterior end of the shell proves that it is a slit limpet, but this feature is often very inconspicuous in gerontic specimens. Typical shell length around 70mm, very large specimens may exceed 95mm. It used to be placed in the genus Tugali (hence the common name), but is now moved to Scelidotoma. Although the external appearance is similar to abalones, its flesh is said to taste bitter and vile when raw and tasteless when cooked. It is one of the host species of the symbiotic scale worm (Polychaeta: Polynoidae) Arctonoe vittata (Grube, 1855), which lives in the pallial groove of the host. The host helps the worm move about and protects it from predators, the worm does not feed on the host and in return helps the host fight off predators such as sea stars by biting them.
Bathymodiolus hirtus Okutani, Fujikura & Sasaki, 2004 <br /> MYTILIDAE<br /> -641m, Methane seep site, Kuroshima Knoll, Off Ishigaki Island, Ryukyu Trench, Japan, 100.0mm, F+, 2004/iv<br /> Bathymodiolus hirtus is a deep-sea chemosymbiotic mussel endemic to one single cold seepage site in the Ryukyu Trench, Japan on Kuroshima Knoll, off Ishigaki Island, Okinawa. Presumably it houses chemosynthetic endosymbionts in its enlarged gills like other Bathymodiolus species and relies on these for nutrition, although no data has thus far been published on the details and it is likely also capable of filter-feeding. A thick-shelled mussel, it is similar in appereance to some other congeners but peculiarly has conspicuous long peristracal hairs which is unusual for Bathymodiolus. The hairs are especially prominent in young specimens which resembles intertidal mytilids. Typical shell length around 80mm, very large specimens may exceed 100mm. It is virtually unobtainable due to its very restricted habitat and distribution. It co-occurs with another large mussel Bathymodiolus securiformis Okutani, Fujikura & Sasaki, 2004, which is easily distinguished by the much more elongate shell and lack of peristracal hair. While B. hirtus occurs in dense aggregations attached to completely exposed outcrops, B. securiformis aggregations are usually found slightly buried in sediments. Both species belong to the Bathymodiolus childressi Gustafson, Turner, Lutz & Vrijenhoek, 1998 complex and are in fact closer related to Gigantidas than Bathymodiolus sensu stricto (i.e., the clade containing the type species of the genus, Bathymodiolus thermophilus Kenk & Wilson, 1985). Although the Kuroshima Knoll seep site is only about 60km away from Hatoma Knoll, the nearest vent field of Okinawa Trough (on the opposite site of Ishigaki Island), the two differ in depth with Hatoma Knoll being significantly deeper (-700 vs -1400m) and no Bathymodiolus species occur on both sites.
Calliostoma foveauxanum (Dell, 1950) <br /> CALLIOSTOMATIDAE<br /> -150m, 14.5km (9 miles) off Cape Saunders, Otago, South Island, New Zealand, 44.4mm, F+, 1993<br /> The "Foveaux Top" is a large and handsome calliostomatid endemic to a small part of New Zealand, ranging from the southern South Island to Stewart Island and the Snares. An uncommon species, it is a carnivorous grazer mostly feeding on hydroid cnidarians. It is best known from moderate depths of -50~200m but ranges deeper with records exist from exceeding -500m. Authors who accept the finer breakdown of Calliostomatidae place this species in the New Zealand endemic genus (or subgenus) Maurea. Typical shell length around 50mm, very large specimens may reach 65mm. The specific epithet is taken from the type locality, the Foveaux Strait. It is most similar to Calliostoma spectabile (Adams, 1855) from the Antipodes Islands of New Zealand, but C. foveauxanum has finer sculpture and the earlier teleoconch are less convex in form. Calliostoma eminens Marshall, 1995 is another closely related species from Antipodes Islands but is easily distinguished by its much deeper suture and very sloped shoulder.
Buccinum kashimanum Okutani, 1964 <br /> BUCCINIDAE<br /> -800~900m, Trawled, Off Kinkasan, Miyagi Prefecture, Japan, 85.1mm, F, 2008/vi<br /> The "Kashima-nada Whelk" is a large cold-water buccinid endemic to the Pacific Japan, ranging from Kagoshima Prefecture to Hokkaido. The inflated white shell is thin and fragile, with a light yellowish brown periostracum which are usually pustulate. It is extremely variable in the development of spiral ribs and has several forms ranging from completely lacking (the depicted form) to two very strongly raised ribs (holotype form) to having numerous weak ribs. The overall form is less variable, although may be considerably more elongate than the depicted form; the name Buccinum boucheti Tiba, 1984 (replacement name for Buccinum concinnum Tiba, 1980 which is a junior homonym of B. concinnum Dillwyn, 1817) was given to the elongate form, now a synonym of B. kashimanum. It is a locally uncommon carnivorous / scavenging gastropod inhabiting sandy to muddy bottoms of deep water ranging from -500~2000m. Typical shell length around 80mm, very large specimens may exceed 100mm. Although it very rarely appears on the fish market, it is one of the most delicious Japanese Buccinum species. It is named after its type locality Kashima-nada, a section of the Pacific Japan ranging from Oarai, Ibaraki Prefecture to Inubousaki ( = Cape Inubo), Chiba Prefecture.
Eugeniconus nobilis skinneri (da Motta, 1982) <br /> CONIDAE<br /> -15~20m, Dived, Bali Island, Indonesia, 41.1mm, F++, 2004/x<br /> The "Skinner's Cone" is a flamboyant conid known from a small part of Indonesia ranging from Bali to Sumbawa. It is considered either a subspecies or colour form of the "Noble Cone" Eugeniconus nobilis (Linnaeus, 1758), which is very variable in pattern and ranges more widely from Andaman Islands to Timor. A predatory vermivorous gastropod feeding mainly on polychaete worms, it inhabits sandy bottoms of very shallow to shallow water ranging from -1~20m deep. Live specimens carry a very thin and translucent yellowish periostratum. Typical shell length around 45~50mm, but very large specimens may reach 70mm. It is similar to E. n. victor (Broderip, 1842) which is differentiated by the two more densely packed and concentrated bands of alternating dark brown and white, as well as the smaller size (to 50mm). The penis and radula sac morphology also differ between the two.
Bathymodiolus mauritanicus von Cosel, 2002 <br /> MYTILIDAE<br /> -1200m, Trawled by the M.P. "Peixe de Mar", Methane seep site, 18°41'N 16°45'W, Off Nouakchott / Banc d'Arguin, Mauritania, 98.6mm, F++, 1994/i<br /> Bathymodiolus mauritanicus is a deep-sea mussel endemic to cold seeps of the Atlantic Ocean. Unusually for a bathymodioline it was not described from samples collected during submersible dives but instead using specimens trawled commercially from -1000~1200m off Mauritania. Since its description it has been discovered at many more sites on both eastern and western Atlantic ranging from the Barbados prism to the Angola margin, and is therefore considered a bathyal amphi-Atlantic species with a depth range around -1000~1700m. It is likely to rely on endosymbiotic bacteria inhabiting its gills for a large part of the nutrition like other Bathymodiolus species, while also being capable of filter-feeding. It is a member of the Bathymodiolus childressi Gustafson, Turner, Lutz & Vrijenhoek, 1998 complex, recognised from recent phylogenetic studies as being a separate clade from Bathymodiolus sensu stricto (ie. the clade characterised by Bathymodiolus thermophilus Kenk & Wilson, 1985) and contains further species from the Western Pacific and off New Zealand, such as Bathymodiolus platifrons Hashimoto & Okutani, 1994 and Bathymodiolus tangaroa Cosel & Marshall, 2003. The speices in this complex differ from Bathymodiolus s.s. morphologically by having low, almost terminal umbones, smaller adductor scar, among other features. The genus Bathymodiolus as a whole is now known to be paraphyletic as other mytilids (e.g., Adipicola crypta (Dall, Bartsch & Rehder, 1938)) appears nested among Bathymodiolus species in phylogenetic analyses, and thus erection of a new genus is likely required in the future to house the B. childressi complex. Currently many authors enclose the genus in quotation marks for this complex to indicate their questionable genus-level placement. In fact the entire subfamily Bathymodiolinae requires a revision in the near future, and recent evidences suggest that Bathymodiolinae perhaps should be incorporated into Modiolinae. Typical shell length around 90mm, very large specimens may exceed 110mm. Although it is common where it is found its bathyal habitats are inaccessible and thus it is very rarely seen in the shell trade. Nonetheless, a considerable number of specimens trawled off Mauritania in 1994 (including the depicted specimen) have made it to the market, making it easier to obtain than other Bathymodiolus species.
Calyptogena (Abyssogena) kaikoi Okutani & Métivier, 1986 <br /> VESICOMYIDAE<br /> -3761m, Dai-san Tenryu Canyon cold seep site, Enshu-nada, Nankai Trough, Japan, 100.0mm, F++, 1997/viii<br /> The "Kaiko's Calyptogena" is a large chemosymbiotic vesicomyid endemic to methane seeps of Nankai Trough, southeastern Japan. Like other chemosymbiotic vesicomyids it has a much enlarged gill presumed to host endosymbiotic bacteria although the details are unknown for this particular species; it is known to derive nutrients from the process of chemosynthesis through the bacteria. It lives half-buried in sediments of deep-sea seeps of bathyal to abyssal depths ranging between -3500~4800m, and is known from the following sites: Tenryu Canyon, Dai-san Tenryu Canyon, Dai-ichi Minami-Muroto Knoll, and off Cape Murato. The white, chalky shell is covered by a moderately thick periostracum; which is naturally lost in older parts of the shell. Although locally common, it is virtually unobtainable due to the extreme depths it inhabits as well as the patchy nature of distribution. Typical shell length around 80mm, very large specimens may exceed 110mm. It is named in honour of the Japanese-French "Kaiko" Project (1985) which investigated deep-sea subduction zones around Japan and discovered for the first time many cold seeps and organisms living there, including this one.
Bathymodiolus platifrons Hashimoto & Okutani, 1994 <br /> MYTILIDAE<br /> -1482m, Hatoma Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 119.6mm, F++, 2014/ii<br /> Bathymodiolus japonicus is a deep-sea mussel endemic to chemosynthetic environments of Western Pacific and is best known from Japan where it is found in seep sites in Sagami Bay and most hydrothermal vent fields in Okinawa Trough, ranging from -950~1550m deep. It is usually the most abundant mussel species where it is found, forming extensive and dense mussel beds. In vents it occurs mostly not directly adjacent to vent effluents but some distances away, around aggregationso of the squat lobster Shinkaia crosnieri Baba & Williams, 1998. It hosts methane-oxydising endosymbiont bacteria in enlarged gills and has reduced digestive system as a result of relying on endosymbionts for nutrition, although it is also capable of filter-feeding. The average shell length is around 90~100mm but very large specimens may exceed 120mm. In many sites it co-occurs with another similar species, Bathymodiolus japonicus Hashimoto & Okutani, 1994; which is similar but the umbones of B. japonicus is subterminal and more posterior than B. platifrons's which are usually on the same plane as the anterior edge of the shell. B. japonicus also has darker periostracum than B. platifrons and therefore generally identifiable even from a distance. Both species belong to the Bathymodiolus childressi Gustafson, Turner, Lutz & Vrijenhoek, 1998 complex and are in fact closer related to Gigantidas than Bathymodiolus sensu stricto (i.e., the clade containing the type species of the genus, Bathymodiolus thermophilus Kenk & Wilson, 1985).
Symmetromphalus regularis McLean, 1990 <br /> NEOMPHALIDAE<br /> -3640m, Alice Springs Hydrothermal Vent Field, Mariana Trough, Northern Mariana Islands, 15.7mm, F++, 1987/v<br /> Symmetromphalus regularis is a limpet-form neomphalid endemic to very deep hydrothermal vents of the Mariana Back-Arc Basin off Northern Mariana Islands, ranging from -2900~3700m in depth. Mainly inhabiting walls of hydrothermal vent chimneys where it forms dense aggregations, it is an intriguing sexually dimorphic species with males being much smaller than females and the left tentacle modified into a penis. Although presumed to filter-feed using its large gills the details of its feeding habits are not wholly known and it may have ectosymbiotic relationship with chemosynthetic bacteria. The apical whorl is coiled and consistent but the body whorl, especially the shape of aperture margin, varies greatly according to the contour and texure of the substrate. Typical shell length around 15mm, very large specimens may exceed 20mm. Though locally common where it is found, the bathyal depth and its very patchy distribution makes it extremely difficult and rare to obtain. The family Neomphalidae is endemic to chemosynthetic ecosystems and members are extremely variable in shell form, from limpet-form to neritiform to trochiform to detached scalariform. The genus Symmetromphalus is endemic to vents of Western Pacific, its only described congener is S. hageni Beck, 1992 from the Manus Back-Arc Basin although another undescribed species is known from North Fiji and Lau Back-Arc Basins.
Bathymodiolus mauritanicus von Cosel, 2002 <br /> MYTILIDAE<br /> -1200m, Trawled by the M.P. "Peixe de Mar", Methane seep site, 18°41'N 16°45'W, Off Nouakchott / Banc d'Arguin, Mauritania, 98.6mm, F++, 1994/i<br /> Bathymodiolus mauritanicus is a deep-sea mussel endemic to cold seeps of the Atlantic Ocean. Unusually for a bathymodioline it was not described from samples collected during submersible dives but instead using specimens trawled commercially from -1000~1200m off Mauritania. Since its description it has been discovered at many more sites on both eastern and western Atlantic ranging from the Barbados prism to the Angola margin, and is therefore considered a bathyal amphi-Atlantic species with a depth range around -1000~1700m. It is likely to rely on endosymbiotic bacteria inhabiting its gills for a large part of the nutrition like other Bathymodiolus species, while also being capable of filter-feeding. It is a member of the Bathymodiolus childressi Gustafson, Turner, Lutz & Vrijenhoek, 1998 complex, recognised from recent phylogenetic studies as being a separate clade from Bathymodiolus sensu stricto (ie. the clade characterised by Bathymodiolus thermophilus Kenk & Wilson, 1985) and contains further species from the Western Pacific and off New Zealand, such as Bathymodiolus platifrons Hashimoto & Okutani, 1994 and Bathymodiolus tangaroa Cosel & Marshall, 2003. The speices in this complex differ from Bathymodiolus s.s. morphologically by having low, almost terminal umbones, smaller adductor scar, among other features. The genus Bathymodiolus as a whole is now known to be paraphyletic as other mytilids (e.g., Adipicola crypta (Dall, Bartsch & Rehder, 1938)) appears nested among Bathymodiolus species in phylogenetic analyses, and thus erection of a new genus is likely required in the future to house the B. childressi complex. Currently many authors enclose the genus in quotation marks for this complex to indicate their questionable genus-level placement. In fact the entire subfamily Bathymodiolinae requires a revision in the near future, and recent evidences suggest that Bathymodiolinae perhaps should be incorporated into Modiolinae. Typical shell length around 90mm, very large specimens may exceed 110mm. Although it is common where it is found its bathyal habitats are inaccessible and thus it is very rarely seen in the shell trade. Nonetheless, a considerable number of specimens trawled off Mauritania in 1994 (including the depicted specimen) have made it to the market, making it easier to obtain than other Bathymodiolus species.
Lyria cloveriana Weaver, 1963 <br /> VOLUTIDAE<br /> -20~25m, From net of local fisherman, Tangalla, Sri Lanka, 89.4mm, F+, 2014/vi<br /> The "Clover's Lyria" is a pleasing and well sought-after volute endemic to Sri Lanka. A carnivorous and predatory gastropod, it inhabits sandy to muddy bottoms of moderate depths around -20~80m. Although once ago a rare species, it is only somewhat uncommon today thanks to many being bought up as by-catch of local fisheries. The shell is rather variable in stoutness but general pattern and the characteristically bulbous protoconch are distinctive features. Typical shell length around 75mm, giant specimens are known to surpass 95mm. It was named after the renowned American conchologist and shell dealer Phillip W. Clover, who is still very much active today.
Provanna glabra Okutani, Tsuchida & Fujikura, 1992 <br /> PROVANNIDAE<br /> -1150m, Cold seep site, Off Hatsushima, Sagami Bay, Japan, 10.9mm, F++<br /> Provanna glabra is a small provannid endemic to the cold seep chemosynthetic ecosystems of Sagami Bay, Japan; and is known from three sites including off Hatsushima, Sagami Knoll, and Okinoyama Bank. With an average density of 300 individuals per square metre, it is the most abundant megabenthos of the Sagami Bay seeps and is usually found on or around large bivalves especially Calyptogena spp.. It is considered a grazing gastropod ingesting bacterial mats and detritus, and is only found in deep to bathyal depths ranging between -800~1500m. Although for many years the Provanna populations in the hydrothermal vent fields of Okinawa Trough　were also attributed to this species, recent genetic investigations and in-depth morphological comparisons revealed them to represent a separate new species which is currently under description. The spire is always corroded away and the periostracum varies from olive to dark brown in colouration. Typical shell length around 10mm and very large specimens may exceed 13mm; giant specimens do exist but these often have very corroded spire and thus shell length is not a truly reliable size measurement for this species.
Vasum rhinoceros (Gmelin, 1791) <br /> TURBINELLIDAE<br /> SCUBA dived, On shallow reef, Off Nungwi, Zanzibar Island, Tanzania, 82.4mm, F++, 2011<br /> The "Rhinoceros Vase" is a very thick and heavy vase shell endemic to a small part central east Africa, ranging from Kenya and Tanzania including Zanzibar Island. It is a carnivorous and predatory gastropod primarily feeding on polychaetes and sipunculans. A shallow water dweller, it may be found from intertidal waters down to approximately -20m deep and inhabits sandy to rocky to weedy bottoms just within fringing coral reefs. Although a locally common species, it is uncommon on the market due to its restricted range. It is generally a rough shell and is very variable in pattern and form, especially knobbyness. The depicted specimen is a particularly spiny form known only from Tanzania which strongly reminiscent of the rare Vasum stephanti Emerson & Sage, 1988 from Somalia. There is also a rare golden form endemic to Zanzibar Island with a uniformly yellow shell and a golden columella, lacking the usual brown pattern. In some geronic specimens the anterior part of the outer lip strongly flares. Typical shell length around 70mm, very large specimens are known to exceed 100mm.
Murex echinodes Houart, 2011 <br /> MURICIDAE<br /> Beached, Between Ras Al Sawadi and Dibah, Gulf of Oman, Oman, 116.5mm, Dead/F+<br /> Murex echinodes is a recently described Murex species endemic to a small part of northwest Indian Ocean, from Gulf of Oman to Kuwait. It is part of a complex which also includes Murex scolopax Dillwyn, 1817, Murex somalicus Parth, 1990, and Murex megapex Neubert, 1998; and was considered as a form of M. scolopax until 2011 when Roland Houart remarked on their consistent differences and described it as a new species. Adult specimens are most easily differentiated from M. scolopax by the existence of a short but obvious second primary spine (P2 sensu Merle, 2005), which is lacking in adult M. scolopax (also M. somalicus). Compared to the very rare M. megapex only known from the types, it has a much smaller protoconch with less whorls (1.6-1.75 vs 3 in M. megapex) and lacks the lattice sculpture on the earlier whorls. There are many more intriguing distinctions between the species in this complex listed in the description paper (Houart, 2011) such as ontogenic differences, readers are referred there for further information. It is a carnivorous and predatory gastropod inhabiting shallow water from the very low tide zone to about -50m deep, and is uncommon to rather rare. The colouration is white to light tan, fresh collected specimens often have brown flammules all over the shell. Typical shell length around 110mm, very large specimens may exceed 150mm.
Busycon coarctatum (Sowerby I, 1825) <br /> BUCCINIDAE<br /> -80m, Trawled on muddy sand bottom, Cabo Catoche, Yucatán Peninsula, Quintana Roo, Mexico, 113.9mm, F+/F++, 2007/i<br /> The handsome "Turnip Whelk" is a Busycon whelk with stunning flame patterns, endemic to the Yucatan Penninsula and Bay of Campeche in Mexico. It is a classic rarity selected by S. Peter Dance as one of his 50 "Rare Shells" (1969), the first traceable specimen appeared in the early 19th Century and was in the collection of Charles Bennet (ie. the 4th Earl of Tankerville). After the death of Tankerville this specimen became the basis for its description (ie. the holotype) by Sowerby I in 1825, but for 125 years after the description it was so rare that "money could not buy it". Although it has become more available today it is still a rarely offered species and very uncommon in collections, especially so outside North America. It is a carnivorous and scavenging gastropod inhabiting moderately depths around -40~120m; most specimens are trawled on sandy to muddy bottoms. A little-varied species, its squat whorls and the narrowly confined anterior siphonal canal are unique among the genus Busycon and makes it unmistakable. Typical shell length around 130mm, very large specimens may exceed 180mm.
Margarites shinkai Okutani, Tsuchida & Fujikura, 1992 <br /> MARGARITIDAE<br /> -860m, Cold seep site, Off Hatsushima Island, Sagami Bay, Kanagawa Prefecture, Japan, 13.2mm, F++<br /> Margarites shinkai is a deep-sea margaritid top shell endemic to chemosynthetic environments of Japan. Remarkably it is able to live in both cold seep and hydrothermal vent fields, and is hitherto known from cold seep sites of Sagami Bay and the Izena Cauldron hydrothermal vent field of Okinawa Trough. Its distribution is disjunct as it is not found in other chemosynthetic sites between these two localities approximately 1500km apart, and may indicate requirement of specific environmental conditions or poor sampling of some sites. Considered to be a grazer of microbial mat and detritus, it is found living on and around large chemosynbiotic bivalves such as Calyptogena spp. in bathyal depths around -1100~1400m. The shell is a beautiful silvery grey with about 10 fine spiral ridges and show prismatic reflections under light, the periphery is angulated. It is named after the manned research submersible "Shinkai 2000" which first discovered it; the word "shinkai" meaning "deep-sea" in Japanese. Typical shell length around 15mm, very large specimens may exceed 20mm. It may be differentiated from the other congeneric chemosynthetic gastropod M. ryukyuensis Okutani, Sasaki & Tsuchida, 2000 by its much weaker sculpture, more compressed shell, larger umbilicus, and radula characteristics (8 laterals vs 10 in M. ryukyuensis).
Tellina foliacea Linnaeus, 1758 <br /> TELLINIDAE<br /> -2~5m, Phi Phi Islands, Krabi Province, Thailand, 94.2mm, F+, 2012<br /> The "Foliated Tellin" is an extremely beautiful tellinid ranging from Amami, Japan to Philippines to northern Australia. Famous for its wonderful colouration resembling that of autumn leaves or the sunset, it is widely coveted by beachcombers and shell collectors alike. It is a filter-feeding and burrowing bivalve inhabiting shallow sandy bottoms around -2~30m deep, freshdead shells are regularly washed up on the beach. It is quite common throughout its distribution, most specimens originate from Thailand and Philippines. It is currently placed in subgenus Phylloda, which some authors consider a full genus. Typical shell length around 75mm, very large specimens may exceed 110mm.
Tellina spengleri Gmelin, 1791 <br /> TELLINIDAE<br /> Very low tide, Sand flats, Andaman Sea, Trang Province, Thailand, 67.5mm, F++, 2012<br /> The "Spengler's Tellin" is a curiously shaped Western Pacific tellinid ranging from Okinawa, Japan to around Borneo and Indonesia. The two valves are strongly bent in the opposite direction and it is thus arc-shaped when viewed from the umbo. The shell is intricately sculptured with numerous strong concentric and ending in a row of spines in the posterior angle, as well as more rows of spines on the posterior slope and the anterior-dorsal edge. A common burrowing filter-feeding bivalve inhabiting sandy to muddy bottoms of shallow water from low tide zone to about -20m, shells are often washed on shore after the animal dies. Typical shell length around 60mm, very large specimens may exceed 80mm.
Calyptogena (Phreagena) soyoae Okutani, 1957 <br /> VESICOMYIDAE<br /> -1167m, Cold seep site, Off Hatsushima, Sagami Bay, Japan, 91.5mm, F++, 1990s<br /> Calyptogena soyoae is a large vesicomyid endemic to cold seeps and perhaps the most famous chemosynbiotic bivalve of the western Pacific. First described in 1957 by the eminent malacologist Prof. Takashi Okutani using dead shells from Sagami Bay, live specimens were not known until 1984 when the first chemosynthetic ecosystem was accidentally discovered in Japan: a cold seep site off Hatsushima, Sagami Bay characterised by a great density of this clam. For a long time it was considered endemic to Sagami Bay, in seepage sites off Hatsushima Island, Okinoyama Bank, and Sagami Knoll ranging from -750~1200m in depth (type specimens are dead collected from -750m, off Jogashima Island but this site is not well-explored); but recent genetic studies indicate that Calyptogena (Phreagena) kilmeri Bernard, 1974 from seeps of British Columbia, Canada to Monterey Bay, USA is actually the same species and a junior synonym. Furthermore, population genetics analyses also revealed a cryptic species complex involving a morphologically very similar but genetically separated sister species Calyptogena (Phreagena) okutanii Kojima & Ohta, 1997 which has wider distribution and is also capable of inhabiting hydrothermal vents in Okinawa Trough. The two sister-species lives mixed in Sagami Bay seeps (ratio is about 1:3 for C. soyoae : C. okutanii) and are probably reproductively isolated. Compared to C. soyoae, C. okutanii generally has a more elongated shell with a stronger excavation and keel in the middle of each valve. It has a much enlarged gill housing sulphur-oxidising chemosymthetic endosymbionts and relies on these for nutrition; the digestive tract is reduced. It lives buried in sediments and extends the foot deep into the sediment to extract hydrogen sulphide for the endosymbionts. As the microdistribution of seepage activity changes from time to time it is capable of crawling around using its powerful foot to locate spots with sufficient hydrogen sulphide input and is thus surprisingly mobile. The animal is blood-red in appearance due to its usage of haemoglobin for oxygen carrier. Its rather thick periostracum is yellowish brown to dark brown, and is mostly corroded away in the earlier parts of the valves. Although locally common, its extremely restricted habitat makes it very difficult to obtain. Typical shell length around 100mm, very large specimens may attain 130mm. It is named in honour of the Fisheries Research Agency (Japan) research vessel "Soyo-Maru" which trawled the type specimens.
  • Prev
  • 1
  • 2
    • ...
  • 11
  • 12
    • 13
  • 14
  • 15
    • ..
  • 19
  • 20
  • Next
  • Prev
  • Next

Copyright © Chong Chen 2013-2021 All Rights Reserved.

Proudly powered by WordPress