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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.

Homalocantha anatomica pele (Pilsbry, 1918) <br /> MURICIDAE<br /> -60ft, Dived on Porites coral reef, Waianae Oahu, Hawaii, USA, 45.1mm, F+++, Coll. Chris Moe<br /> The "Pele's Murex" is an endemic muricid of Hawaii well known for its vibrant colour variations and highly sought-after by collectors. The colour ranges from white to yellow, orange, pink, red, purple etc., and a colour set of quality specimens makes a wonderous display. It is usually treated as a Hawaiian subspecies of Homalocantha anatomica but is considered by some to be a separate full species. It is an uncommon carnivorous gastropod inhabiting a bathymetric range of around -10~50m. Typical shell length around 45mm, very large specimens may exceed 60mm.
A "shell" which deceives!<br /> <br /> Hydrissa sodalis (Stimpson, 1859) <br /> HYDRACTINIIDAE<br /> -50m, Hokkaido, Japan, 54.3mm, F+/F++<br /> It may be difficult to believe but this "shell" is not made by a mollusc, but a species of shell-mimic hydrozoan. Hydrozoans are not molluscs but cnidarians, a phylum characterised by stinging cells called cnidocytes that includes animals such as corals and jellyfish. This colonial species forms commensal relationship with a hermit crab species, Pagurus constans (Stimpson, 1858); it protects the hermit crab with its sting and the hermit crab leads it to food. The hydroids first settle on small gastropod shells on young hermit crabs, and the polyps slowly grow and increase in number to cover the entire shell. The amazing thing is that the hydroid colony "shell" grows like a gastropod shell as the hermit crab grows larger, and thus the hermit crab does not need to change its shell throughout whole life. It is an omnivorous species ranging from Sea of Okhotsk to Kyushu, Japan (actual range may be wider in the north); living in rather deep water from about -30~400m. The average size is around 50mm, very large specimens may exceed 70mm.
Aulacofusus periscelidus (Dall, 1891) <br /> BUCCINIDAE<br /> -400m, Off Kunashir Island, Kuril Islands, 61.3mm, F++, 2009/viii<br /> The "Garter Whelk" is an attractively sculptured buccinid ranging from Alaska to Russia to Hokkaido, Japan. An uncommon species but rarely seen on the market, it is a carnivorous snail living on rocky to sandy/muddy substrates from about -20~400m deep. The siphonal canal appears to vary in length and distinctiveness between individuals. Typical shell length around 60mm, large specimens can exceed 85mm. Live specimens are often covered by a layer of overgrowth made by other marine organisms, such as bryozoan and algae.
Ifremeria nautilei Bouchet & Warén, 1991 <br /> PROVANNIDAE<br /> -2000m, White Lady Hydrothermal Field, North Fiji Basin, 58.2mm, F++, early 1990s<br /> The "Black Snail", as this species is often referred to as during expeditions in contrast to the "White Snail" Alviniconcha, is a gigantic provannid gastropod endemic to hydrothermal vents of North Fiji Basin, Manus Basin, and Lau Basin in the Pacific Ocean ranging from -1700~2800m in depth. It is unique among gastropods in exhibiting internal brood protection for a specialised type of larva ("Warén's larva") in a modified pedal gland. Like its close cousin Alviniconcha (they are sister genera) it houses chemosynthetic endosymbionts in its enlarged gill and rely on them for nutrition; their common ancestor most likely acquired gammaproteobacteria symbionts before the two split and took different evolutionary paths. It is named in honour of IFREMER, France's national oceanographic institute, and its manned deep-submersible Nautile which discovered this species. Typically it is black in colouration with a metallic sheen presumably due to hydrothermal deposits; the depicted specimen shows the true colour of the original periostracum. The spire is always heavily corroded leaving only 1.5~3 whorls. Typical shell length around 70mm, very large specimens can exceed 100mm. Unfortunately its habitats are accessible with deep-submersibles only and thus it is virtually unobtainable for shell collectors.
Alviniconcha hessleri Okutani & Ohta, 1988 <br /> PROVANNIDAE<br /> -3610m, Alice Springs Hydrothermal Field, Mariana Trough, 48.5mm, F+++, 1980s<br /> The "Hairy Gastropod" is one of the most famous representatives of hydrothermal vent endemic molluscs and unmistakable with its heavily hirsute periostracum. It houses chemosynthetic endosymbionts in greatly enlarged gill and relies on these for nutrition, the digestive system is reduced as a consequence. Although once thought to be widely distributed from Mariana Trough (its type locality) to Kairei Field in the Central Indian Ridge, genetic studies have revealed at least three cryptic species (Mariana, North Fiji to Manus, and Central Indian Ridge); and thus only populations from Mariana Trough should be referred to as the species A. hessleri. It is best known from Alice Springs field (about -3600m) and Forecast field (-1470m), where individuals form dense aggregations on vent chimneys dominating areas closest to the vent effluent. It uses both hemocyanin and hemoglobin for oxygen carrier. It is named after the American manned deep-submersible Alvin and deep-sea biologist Robert R. Hessler. The typical shell length is around 45mm, large specimens may approach 60mm. The other species ranging from North Fiji to Manus basin is much larger and may exceed 80mm; it often co-occurs with another large provannid Ifremeria nautilei Bouchet & Warén, 1991, whose aggregations frequently surround that of Alviniconcha. Like most other vent endemic molluscs, Alviniconcha is virtually unobtainable for shell collectors due to its extremely inaccessible habitat.
Lambis pilsbryi Abbott, 1961 <br /> STROMBIDAE<br /> -10~15m, Dived, Nuku Hiva, Marquesas, 172.3mm, F++<br /> The "Pilsbry's Spider Conch" is a large spider conch endemic to the French Polynesia and best known from the Marquesas Islands. For a long time it was regarded as a subspecies of Lambis crocata (Link, 1807) but now often recognised as a full species. It can be differentiated from L. crocata by lack of a large bulge in the columella and longer digits, as well as being much larger on average. Once considered rare due to its limited range but now it is only uncommon on the market. Presumably a herbivore / detritivore like other spider conchs, it inhabits shallow intertidal waters down to about -40m deep. Two forms exist, the slender form shown with long digits and a robust form with larger body and relatively shorter digits. The typical shell length is about 200mm including digits, giants are known to exceed 250mm.
Entemnotrochus rumphii (Schepman, 1879) <br /> PLEUROTOMARIIDAE<br /> -180m, Trawled, East China Sea, 92.8mm, F+, 2013/xii<br /> The "Rumphius' Slit Shell" is the largest of all known extant slit shells and a species of legendary fame among collectors. Only three specimens were known until 1969 when a fourth one turned up in Taiwan. Toba Aquarium in Japan purchased that specimen with 10,000USD, which is often cited as the most expensive shell in history. Nowadays it is still rare but is obtainable at a cost, although recently specimens from East China Sea are exchanging hands at relatively low price. It ranges from Honshu, Japan to Taiwan to Philippines inhabiting rather deep water around -50~400m deep. It is a grazer mostly feeding on sponges but also soft corals, and is mostly found on rocks where these grow. The average adult size is around 180mm, with very large specimens exceeding 250mm. The final whorl inflates and exhibit most clearly the "flame patterns" this species is known for. Young specimens such as the one shown tends to have yellow colouration, whereas mature specimens are dominated by red.
Fulgoraria hirasei (Sowerby III, 1912) <br /> VOLUTIDAE<br /> -250~300m, Kumano-Nada, Off Owase City, Mie Prefecture, Japan, 186.2mm, F+/F++, 2009/vi<br /> The "Hirase's Volute" is a large volute endemic to Pacific side of Japan. It is a representative species of Fulgoraria, a genus of slender deep-water volutes which Japan is famous for having many endemic species. A locally common species, it is a carnivore living on sandy/muddy bottoms in rather deep water about -100~400m in depth and mostly taken by bottom trawlers. The typical shell length is about 140mm but very large specimens are known to reach 230mm, anything over 200mm is rare.
A special gift from Ann Yen. Thank you Ann! :)<br /> <br /> Siphonalia nigrobrunnea Lee & Chen, 2010 <br /> BUCCINIDAE<br /> -100~200m, Off Kueishan Island, Yilan County, Taiwan, 25.3mm, F++, 2011/vii<br /> This is a recently described buccinid only known from waters around Kueishan Island, Taiwan. This area is known to contain many hydrothermal hotspots, and this species is reported from sandy bottoms influenced by hydrothermal activity from -50~200m deep. First discovered from products of shrimp trawlers, it is not clear yet if is endemic to vent fields or also found in off-vent seafloor. Its habitat is quite shallow for hydrothermal vent associated species and thus specimens are seen on the market, albeit rarely outside Taiwan. It is presumably a carnivore / scavenger like other congeners. The typical shell length is around 30mm, much smaller than the closely related Siphonalia spadicea (Reeve, 1846) which is also found in the same area.
Paziella pazi (Crosse, 1869) <br /> MURICIDAE<br /> -200~250m, Trawled, Caribbean Sea, Cuba, 36.6mm, F+, 1984/vi<br /> The "Paz's Murex" is an uncommon muricid native to the Caribbean Sea and adjacent waters, ranging from Florida Keys to French Guiana. It is a predatory gastropod inhabiting rather deep water around -30~550m. A spiny species, the number of varices can range from six to eight per whorl. The typical shell length is around 40mm but it is very variable in size and giants are said to reach even 90mm.
Calliostoma scotti Kilburn, 1973 <br /> CALLIOSTOMATIDAE<br /> -40~45m, Trawled, Natal, South Africa, 38.5mm, F++, 2002/vi<br /> The "Scott's Top Shell" is a very beautiful top shell with golden colouration and attractively keeled shell. It is distributed from Mozambique to South Africa, and is a herbivore / detritivore mostly found on sandy to muddy bottoms between -30~400m deep. It is locally moderately common but it is rather variable in colouration, form, and sculpture and handsome specimens like the one shown are uncommon. Typical shell length around 35mm, giants may approach 45mm.
Cellana mazatlandica (Sowerby I, 1839) <br /> NACELLIDAE<br /> Intertidal on rocks, Chichi-jima, Bonin Islands, Japan, 82.4mm, F+, 1980/viii<br /> Contrary to the specific epiphet, the "Bonin Islands Limpet" is not distributed in Mazatlán, Mexico but is a famous endemic species of the Bonin Islands (aka. Ogasawara Islands), Japan. Sowerby I is said to have mistaken the locality when giving this species a name. Although for a long time it was known as C. boninensis (Pilsbry, 1891), a much better and descriptive name, due to the strict rules of zoological nomenclature it is now synonymised with C. mazatlandica and we are stuck with that senior name. This species is famous and significant because it is the only marine gastropod recognised as a natural monument in Japan and protected by law from collection (since 1970/xi/12). Thus although it is locally common in its habitat it is quite uncommon on the market. It is an intertidal grazer feeding on microalgae films, characterised by a tall shell and very strong radial ribs. It is a large cellanid, the typical shell length is about 70mm but very large specimens may reach 100mm.
Turriconus excelsus (Sowerby III, 1908) <br /> CONIDAE<br /> -120~150m, Tangle net, Panglao, Bohol, Philippines, 67.2mm, F++, 2004/iii<br /> The "Illustrious Cone" is one of the most coveted rare cones of all, and surely one of the most attractive. It is a very famous species included in S. Peter Dance's fifty "Rare Shells" (1969), only three specimens were known then and none of them fresh. A predatory gastropod living in rather deep water of about -100~400m, it has a wide distribution range in the Indo-Pacific ranging from Burma to Philippines to Japan to northern Australia to Solomon Islands. Most specimens seen on the market today comes from Balut and Aliguay islands of Philippines. Average shell length around 75mm, gigantic specimens may exceed 100mm. Its colour and pattern are both quite variable and the now synonymised name T. nakayasui (Shikama & Habe, 1968) was given to a form with less patterns than usual. It is the rarest of the three famed cones characterised by tall, stepped spires; the other two being Cylinder gloriamaris and Leptoconus milneedwardsi.
Annepona mariae (Schilder, 1927) <br /> CYPRAEIDAE<br /> New Caledonia, 14.2mm, F+++<br /> Described by Franz Schilder who dedicated the specific epiphet to his wife, the "Maria's Cowrie" is one of the most lovely cowries of all with its unique eye-catching brown fringed yellow spots. An omnivore, it has a very wide range throughout the Indo-Pacific ranging from east Africa to northern Australia to Philippines to Hawaii to French Polynesia. The depth range of this nocturnal cowry is approximately -5~45m. The spotted pattern vary greatly between individuals, usually at least some parts are blurry; it is difficult to find a specimen with all spots having sharp and well-contrasted edges. The average shell length is around 15mm for this rather uncommon species, although very large specimens may reach 20mm.
Odontocymbiola magellanica (Gmelin, 1791) <br /> VOLUTIDAE<br /> Rio Negro, Argentina, 141mm, F++<br /> The "Magellanic Volute" is a large and common volute found throughout the Magellanic province, ranging from Uruguay to Magellan Strait to southern Chile to Falkland Islands. It is a carnivorous gastropod and can be seen from very shallow intertidal waters down to about -800m deep. Average shell length is around 160mm, but very large specimens may exceed even 240mm. A highly variable species in both form and pattern, various forms have been given different names. Its form ranges from wide and stout to relatively slender with a tall spire; the pattern usually consists of dark zigzag lines. Many specimens lack patterns, however, especially those with rough and worn shells. The tall form is sometimes mistaken with Adelomelon ancilla (Lightfoot, 1786), another common volute from the same area. A. ancilla is in general more fusiform with a smaller body mass than O. magellanica, the radula is also different. Both species are fished for meat and are of some economic importance for local fisheries.
Lioconcha castrensis (Linnaeus, 1758) <br /> VENERIDAE<br /> Cebu, Philippines, 59mm, F++<br /> The "Camp / Zigzag Venus" is a strikingly patterned venus clam widely distributed across the Indo-west Pacific. It is a filter-feeding species which lives buried in sand from lowtide to about -30m deep. The shell is white to light tan in colouration but the pattern varies greatly, generally with dark lines forming tent-like repetitive pattern. Although a common species, it is quite sought-after by collectors for its beautiful pattern. Average shell length around 40~45mm, very large specimens sometimes exceed 55mm; the depicted specimen is a real giant.
Trichotropis bicarinata (Sowerby I, 1825) <br /> CAPULIDAE<br /> Sawara-Cho (now Mori-Cho), Kayabe District, Hokkaido, Japan, 33.7mm, F++, Coll. Shigeo Igarashi, 1978/vi/25<br /> The "Two-Keeled Hairy Snail" is a remarkable capulid with a vast range from northern Japan to British Columbia to New Foundland, Canada to Svalbard Archipelago, Norway. It is a cold water species with a depth range around -10~400m. Capulids are known to vary greatly in shape and sculpture, including some amazing ones like this species. Although it is not uncommon across its range, specimens retaining full periostracum are uncommon as it peels quite readily. Members of genus Trichotropis are generally suspension feeders but some have been reported to be kleptoparasites as well, stealing food from polychaete worms (e.g., T. cancellata and T. conica). It gains its common name from the two strong keels on the shell (also the reason for its specific epiphet) and a light brown periostracum with many hair-like protrusions. The actual shell is milky white with no hairs. Average shell length around 35mm, very large specimens can exceed 45mm.
Propeamussium sibogai (Dautzenberg & Bavay, 1904) <br /> PROPEAMUSSIIDAE<br /> -150~200m, Trawled off Balicasag Island, Philippines, 37.3mm, F+/F++<br /> The "Siboga Glass Scallop" is not a true scallop (Pectinidae) but belongs to a closely related family Propeamussiidae, which includes mainly fragile deep-water species with the lower valve much smaller than the upper valve. It is named after Siboga, the Dutch ship during whose famous 1899-1900 expedition to Indonesia this species was discovered. A filter-feeding species, it has a very wide range including at least Japan to New Zealand to South Africa and lives in rather deep water around -50~400m. Although moderately common, it is very difficult to find a quality specimen due to its extremely fragile shells. The average shell length of the upper valve is around 40mm but in very large specimens this may approach 60mm.
Boreotrophon flos Okutani, 1964 <br /> MURICIDAE<br /> -300~400m, Off Kunashir Island, Kuril Islands, 40.1mm, F++, 2009/viii<br /> Boreotrophon flos is an elegant and fragile muricid species known from northern Japan to Kuril Islands. It appears that most specimens come from around the southernmost islands of Kuril Islands, a disputed area claimed by both Russia and Japan. A rare species, it is very difficult to find specimens with the characteristic upturned wings intact. A carnivorous gastropod, it lives in rather deep water ranging from about -300~800m. Average shell length around 35mm, very large specimens may approach 45mm.
Melapium elatum (Schubert & Wagner, 1829) <br /> STREPSIDURIDAE<br /> -100~150m, Trawled off Inhambane, South Africa, 40.1mm, F++, 1996/viii<br /> With a vivid violet columellar, Melapium elatum is a famous and attractive collector's item known from southern Africa. It is quite uncommon on the market, especially specimens with good colouration as the intensity of purple vary between specimens. It is a carnivorous / scavenging gastropod with a bathymetric range approximating -20~200m, usually taken by trawling. Average shell length around 45mm, although giants may exceed 65mm. The genus Melapium was traditionally considered as strange olive shells and placed in Olividae, but now separated and placed in Strepsiduridae containing only this genus and two species; the other being M. lineatum (Lamarck, 1822).
Haliotis laevigata Donovan, 1808 x rubra conicopora Péron, 1816 <br /> HALIOTIDAE<br /> Farmed, Port Fairy, Victoria, Australia, 132.5mm, F++<br /> This stunning blue abalone is supposedly a hybrid between the "Smooth Australian Abalone" H. laevigata and "Conical Pore Abalone" H. r. conicopora, and is a commercially developed hybrid for meat with increased growth rate. Many abalone species readily hybridize with each other, and hybrids between various species are known all around the world. The shell colouration of abalones reflect colouration of food they eat, and the vivid blue colouration in this specimens is caused by colour and chemicals in artificial feeds. Both parent species are algae grazers on hard substrates such as rocks occuring in shallow water down to -40m deep. They are large abalones with average shell length of around 150mm and maximum length may exceed 200mm. It is rare for hybrids bred by aquaculture to reach large size because they are culled for meat after a certain period of growth. Abalones are considered a delicacy in many cuisines particularly Asian cuisines, and their meat fetch very high prices.
Marginella sebastiani Marche-Marchad & Rosso, 1979 <br /> MARGINELLIDAE<br /> Trawled, Off Pointe des Almadies, Dakar, Senegal, 60.8mm, F++, Collected by local fisherman, 2013/vi<br /> The "Sebastian's Marginella" is a beautifully spotted margin shell ranging from Mauritania to Guinea in west Africa. It is a carnivorous / scavenging gastropod living on sandy bottom with a bathymetric range of approximately -20~100m. It is very variable in size and although the average shell length is around 50m, mature shells range from 35mm to over 70mm. One of many spectacular large, spotted marginellids endemic to west Africa where this family is particularly diverse.
Murex spectabilis Ponder & Vokes, 1988 <br /> MURICIDAE<br /> Bohol, Philippines, 121.7mm, F++<br /> This is a quite uncommon murex species best known from shallow waters of Philippines, although its range supposedly extends to Thailand. A carnivorous species like all Murex, it is similar to Murex pecten but has only seven spines on the siphonal canal which are rather strongly recurved, notably the most anterior one. The opening of siphonal canal zigzags strongly along the length especially in the posterior part, which also helps in differentiating it from other congeners. Average shell length around 110mm, although very large specimens may approach 140mm.
Spondylus reesianus Sowerby III, 1903 <br /> SPONDYLIDAE<br /> -25m, Dived on reef, Davao, Mindanao, Philippines, 95.2mm, F++<br /> Originally known the Maluku Islands, Indonedia, Spondylus reesianus is a striking thorny oyster now known to have a distribution ranging from Japan to Philippines. It is a sessile filter feeder found in moderately deep water, most specimens are collected around -50~200m. It is unique among spondylids to have numerous strong and obvious radial ribs on the shell surface made out of a continuum of fine spines, and thus readily separated from other species. Like many spondylids, young specimens of this species often have spine tips with broad and leafy tips. Although a common species, it is only uncommonly seen on the market. Usually uniformly orange in colouration; average shell length around 90mm, very large specimens may exceed 120mm.
Galeodea rugosa (Linnaeus, 1771) <br /> CASSIDAE<br /> -400m, On mud bottoms, 5 miles off Isla de Alborán, Spain, 96.8mm, F++, 2013/v<br /> The "Rugose Bonnet" is a large bonnet shell native to northeast Atlantic Ocean ranging from the British Isles to West Africa, as well as West Mediterranean. It is a carnivorous gastropod most likely feeding on echinoderms and other molluscs, and is found between a depth range of about -50~700m. The shell is usually cream to orange in colour and covered by a translucent periostracum when alive. The fragile parietal shield varies in extent and is often badly broken. Average shell length around 80mm, large specimens often exceed 100mm.
Acharax johnsoni (Dall, 1891) <br /> SOLEMYIDAE<br /> -180~200m, Trawled by Alaska pollock fishing boat, Off Shiraoi, Hokkaido, Japan, 152.2mm, F++, 2013/xi<br /> The "Johnson's Awning Clam" is a very large solemyid famously known from cold seeps -- a type of chemosynthetic environment often associated with thick sediments where reduced substances such as methane or hydrogen sulphide slowly ooze out of seafloor. It houses sulphide-oxidising endosymbionts in large gills and relies on them energetically; solemyids are well-known for their greatly reduced to even absent digestive tracks due to this. It lives completely buried in sediments in a wide depth range from about -100~5500m, and is found in all reducing sediments and not exclusively in seeps. Best known from Japan, it has an almost global distribution ranging from Morocco to Japan to Alaska to Peru and further; although this may contain some cryptic species. One of the largest solemyid, it is very rare on the market due to its patchy distribution and special habitat. The shell is cream coloured and fragile, covered by a thick dark brown periostracum with wide radiating ribs which characteristically extends far beyond the shell forming digit-like structures. The average shell length is around 80~100mm, the specimen shown is gigantic. Usually when dried the periostracum and shell both cracks and eventually fall to pieces, specimens preserved in good condition like the one shown is extra-rare.
Aporrhais serresianus (Michaud, 1828) <br /> APORRHAIDAE<br /> -500m, Mud bottoms, Isla de Alborán, Spain, 51.5mm, F++, 2013/vii<br /> The "Mediterranean Pelican's Foot" is an elegant aporrhaid ranging from Morocco to west Mediterranean to Iceland. A common species, it can be found on fine mud between very shallow water up to -800m deep but is mostly seen around -100~300m. It is a specialised detritivore feeding on organic material and algae contained in mud. The digits are rather variable in length and curvedness, and the shown specimen has rather long and recurved ones. While the average shell length is around 40~45mm, giants may exceed 60mm.
Ocenebra inornata (Récluz, 1851) <br /> MURICIDAE<br /> -15m, Dived in oyster bed, Posyet Bay, Primorsky Krai, Russia, 51.2mm, F++<br /> The "Japanese Oyster Drill" is a muricid famous as an invasive species. Although the native distribution range of this species is from Sakhalin, Russia to northern China, South Korea, and Japan; it has been introduced to North America and western Europe with exports of the Pacific Oyster Crassostrea gigas (Thunberg, 1793). It is a major predator of oysters and is widely recognised as a great threat to oyster aquaculture both in native and introduced regions, often causing devastating damage. Its vertical distribution is from intertidal waters down to about -20m deep, and it is commonly found on rocks or bivalves. Very variable in sculpture and form like many members of genus Ocenebra, and the specimen shown has very well developed wing-like varices. Average shell length around 40mm, although large specimens may exceed 55mm.
Lotoria perryi (Emerson & Old, 1963) <br /> RANELLIDAE<br /> Tuticorin, Tamil Nadu, India, 127.1mm, F++<br /> The "Perry's Triton" is an attractive triton native to Indian Ocean ranging from Sri Lanka to Mozambique. It is a common carnivorous and predatory gastropod living in shallow water ranging from very shallow water up to about -80m deep. Average shell length around 110mm, large specimens often exceed 130mm. It is the type species of genus Lotoria and is similar to L. lotoria (L., 1758) and L. grandimaculata (Reeve, 1844) but can be distinguished from them by the lack of dark spots on the columellar shield, more knobby form, and more regularly spaced pattern on the varices.
Hydatina albocincta (van der Hoeven, 1839) <br /> APLUSTRIDAE<br /> Trawled, off Kaohsiung, Taiwan, 56.4mm, F++<br /> The "White Banded Bubble" is a rather large shelled opisthobranch widely distributed from Japan to New Zealand to South Africa. It is a common species found across wide depth range from intertidal waters down to -100m, but most abundant around -10~20m. It lives on sandy bottoms and is a predatory species feeding mostly on polychaete worms. As is the norm with shelled opisthobranchs the soft part of the animal is much larger than the shell, and in this species it is beautiful with frilly white edges. Average shell length around 40~45mm, very large specimens like the one displayed can exceed 55mm. The most common pattern is with three regular cream bands (shown), but many variations exist.
Takasagovolva honkakujiana (Kuroda, 1928) <br /> OVULIDAE<br /> -100~200m by tangle net, Balut Island, Philippines, 63mm, F+++, Nov 2013<br /> <br /> Takasagovolva honkakujiana is a large, rare ovulid and one of the most elegant of all. It was first described from the collection of Honkakuji temple in Wakayama Prefecture, Japan by Dr Tokubei Kuroda, hence the specific name. Honkakuji temple has a history of accumulating shells donated by fishermen for more than two centuries and currently houses a collection exceeding 1000 species and 30000 specimens; a pair of this species being the centrepiece. Although most famous in Japan this species has a wide distribution range from Japan to Philippines to Queensland, Australia and even to southeast Africa; but most specimens seen on the market today come from Philippines. It is carnivore and an ectoparasite of gorgonian octocorals and lives in rather deep water ranging from -80~300m. Average shell length around 45mm, exceptionally large specimen such as the one shown may exceed 60mm. It is sometimes confused with its only congener T. gigantea Azuma, which has more slender shell with longer extremities.
Provanna aff. glabra Okitani, Tsuchida & Fujikura, 1992<br /> PROVANNIDAE<br /> -1638m, Irabu Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 10.4mm, F++, ROV Hyper-Dolphin on-board R/V KAIYO, Feb 2014<br /> <br /> Provanna is a widely distributed genus of small gastropods endemic to chemosynthetic ecosystems. Approximately twenty species have been described so far, and they are considered as detritus grazers most of the time although some species may house endosymbiotic bacteria in gills. Like Lepetodrilus, they often dominate their habitats with great abundance. The species widely distributed in Okinawa Trough vents shown here has long thought to be identical to Provanna glabra, the species originally described from cold seeps of Sagami Bay. Recently however, it has become clear that the Okinawa Trough specimens differ slightly and should be treated as a separate species (Fujikura, Okutani & Maruyama, 2008). This species ranges from -600~1500m in water depth and the average shell length is around 8mm but very large specimens may reach 12mm. Like most coiled vent gastropods the spire is always heavily corroded especially in geronic specimens.
Bathyacmaea secunda Okutani, Fujikura & Sasaki, 1993 <br /> PECTINODONTIDAE<br /> -1638m, Irabu Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 13.8mm, F++, ROV Hyper-Dolphin on-board R/V KAIYO, Feb 2014<br /> <br /> Bathyacmaea secunda is a medium-sized limpet restricted to hydrothermal vent fields in Okinawa Trough, Japan. A common grazing species, it is found on Bathymodiolus mussels and other hard substrates. Average shell length around 12~15mm, although some giants can exceed 20mm. In some vent fields such as Hatoma Knoll it is often found sympatrically with its sister species, Bathyacmaea tertia Sasaki, Okutani & Fujikura, 2003, which is differentiated on slight differences in shell shape, sculpture, and radula morphology. The docoglossate radula of this genus is rather strange and each side only has one teeth with very long shafts and subdivided spoon-like cusps.
Iheyaspira lequios Okutani, Sasaki & Tsuchida, 2000 <br /> SKENEIDAE<br /> -1002m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 6.2mm, F++, ROV Hyper-Dolphin on-board R/V KAIYO, Jan 2014<br /> <br /> Iheyaspira lequios is a small trochoid endemic to hydrothermal vent fields of Okinawa Trough, Japan. It was described and best known from Iheya North Knoll field, where it is found in association with Bathymodiolus mussels but also rarely with Shinkaia crosnieri squat lobsters. Presumably a substrate and detritus grazer, it lives around water depth of -1000m. Average shell size around 5mm, very large specimens may exceed 8mm. Although currently placed in family Skeneidae, it has become clear recently that the family Skeneidae is probably best classified as a subfamily under Turbinidae. Many species are placed under Skeneidae based solely on shell morphology, and the true systematic position of many skeneid species requires re-investigation.
Lepetodrilus nux (Okutani, Fujikura & Sasaki, 1993) <br /> LEPETODRILIDAE<br /> -1638m, Irabu Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 8.9mm, F++, ROV Hyper-Dolphin on-board R/V KAIYO, Feb 2014<br /> <br /> Lepetodrilus is one of the most widely distributed vent endemic gastropod genera around the world, and although small these limpets often dominate by their sheer abundance. L. nux is abundantly found in Okinawa Trough vents and is widely distributed across the vent field attached to rocks or other organisms. It is considered as a substrate and detritus grazer but may also filter-feed; other species of the genus such as L. fucensis McLean, 1988 has chemoautotrophic bacteria associated with the gills. The shape and height of specimens vary greatly depending on the substrate, and are not reliable features for identification. Average shell length 5~8mm, very large specimens may reach 12mm. A very similar species, L. japonicus Okutani, Fujikura & Sasaki, 1993 is also known from Okinawa Trough and can only be reliably differentiated by investigating the radula.
Margarites ryukyuensis Okutani, Sasaki & Tsuchida, 2000 <br /> MARGARITIDAE<br /> -1482m, Hatoma Knoll Hydrothermal Vent Field, Okinawa Trough, Japan, 14.8mm, F+, Collected by ROV Hyper-Dolphin on cruise KY14-02, Feb 2014<br /> <br /> Margarites ryukyuensis is a trochoid gastropod endemic to hydrothermal vent fields of Okinawa Trough, Japan ranging from -900~1600m deep. It is presumably an omnivorous grazer detritus grazer found moderately far away from vent effluents and mainly associated with Bathymodiolus mussel beds and peripheral rocks. Like many other vent gastropods, its abundance appears to vary greatly between different vent fields. It is characterised by a thin and slightly glossy green periostracum and seven spiral ridges on the body whorl, the strength of which varies from specimen to specimen. Average diameter around 15mm, very large specimens may reach 20mm.
Thermosipho desbruyeresi (Okutani & Ohta, 1993) <br /> BUCCINIDAE<br /> -1002m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 80.2mm, F+, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> Thermosipho desbruyeresi is a large buccinid endemic to hydrothermal vent fields. It has a wide distribution across Japanese vent sites in Okinawa Trough and Izu-Ogasawara Arc (depth range -600~1400m) and extending more than 8000km to Mariana, North Fiji, and Lau Basins (depth range -1750~2750m). The Japanese population was described as a separate subspecies, T. d. nipponensis (Okutani & Fujiwara, 2000), but was synonymised with T. d. desbruyeresi by Kantor et al (2013). A carnivorous / scavenging species, it has rather low population density and only rarely encountered especially in Okinawa Trough. It is usually found on rock surfaces and also in association with Bathymodiolus mussels. By far the largest gastropod endemic to Okinawa Trough vents, the average shell length is 70~80mm but giants may reach 100mm.
Bathymodiolus platifrons Hashimoto & Okutani, 1994 <br /> MYTILIDAE<br /> -1083m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 58.2mm, F+++, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> Bathymodiolus platifrons is the most abundant mussel species in Okinawa Trough hydrothermal vent fields, usually forming extensive beds around Shinkaia crosnieri squat lobster aggregations. This species is endemic to Japan and also occurs in cold seeps including Hatsushima and Okinoyama sites. It is found within a depth range of -950~1530m, and the average shell length is around 90~100mm but very large specimens may exceed 120mm. Smaller specimens like the one shown here however display more clearly the umbones on the same plane with anterior end of the shell, the important identifying character of this species. It hosts methane-oxydising endosymbiont bacteria in enlarged gills and has reduced digestive system as a result of relying on endosymbionts for nutrition.
Bathymodiolus japonicus Hashimoto & Okutani, 1994 <br /> MYTILIDAE<br /> -1083m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 90.5mm, F+++, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> Famously first discovered from Galapagos Rift with tubeworms and Calyptogena clams, the genus Bathymodiolus contains large to very large mussels specialised for living in chemosynthetic environments, hosting endosymbiotic bacteria capable of chemosynthesis in their gills. They however also filter-feeds like other mytilids to a certain degree. B. japonicus is a species endemic to chemosynthetic environments around Japan, including seep sites in Sagami Bay and vent sites in Okinawa Trough ranging from -705~1170m deep. Its endosymbiont is the methane-oxydising type and uses methane as energy source. Average shell length around 90mm, very large specimens may reach 110mm. It often occurs sympatric in the same habitat with another similar species, Bathymodiolus platifrons, but the umbones of B. japonicus is subterminal and more posterior than B. platifrons' umbones, which are usually on the same plane with the very anterior end of the shell. B. japonicus also has darker periostracum than B. platifrons and therefore may be differentiated even from a distance.
Cantrainea jamsteci (Okutani & Fujikura, 1990) <br /> COLLONIIDAE<br /> -1016m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 15.7mm, F++, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> Cantrainea jamsteci is a medium sized colloniid gastropod endemic to chemosynthetic ecosystems around Japan, named after JAMSTEC -- Japan's national research institute for marine sciences and technology. It is known from hydrothermal vents in Okinawa Trough and a cold seep site, Kuroshima Knoll in Ryukyu Trench; ranging from -600~1000m in water depth. It is apparently an omnivorous detritus layer grazer and mainly found associated with Bathymodiolus mussel beds and Lamellibrachia tubeworm bushes. Very large specimens may approach 20mm in diameter, the average diameter being 15mm. Specimens found close to vent effluents usually are covered in black deposits and the apex is often heavily corroded. The family Colloniidae is closely related to Phasianellidae and they share the thick, calcareous operculum.
Calyptogena okutanii Kojima & Ohta, 1997 <br /> VESICOMYIDAE<br /> -1080m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 165.5mm, F++, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> Another specimen of Calyptogena okutanii. This specimen is a real giant and the largest specimen taken on this cruise. Normally, the average shell length ranges from 100mm to 120mm. Calyptogena okutanii is very similar to C. soyoae, but has slightly more elongate shell and the two show constant difference in genetic sequences.
Safely returned from the cruises! Here's a famous vent bivalve found during the cruise.... : )<br /> <br /> Calyptogena okutanii Kojima & Ohta, 1997 <br /> VESICOMYIDAE<br /> -1080m, Iheya North Knoll Hydrothermal Vent Field, Okinawa Trough, 120.5mm, F++, Collected by ROV Hyper-Dolphin on cruise KY14-01, Jan 2014<br /> <br /> When hydrothermal vent field was first discovered at the Galapagos Rift in 1977, found with it was a out-of-this-world ecosystem that relied on energy not from the sun but from the earth -- dominated by giant tubeworms, giant white clams, and giant mussels. The giant clams, Calyptogena, were then discovered at many vent fields and cold seeps around the world. These clams host endosymbiotic chemosynthetic bacteria in their giant gills and relies on these bacteria for nutrition by supplying them with hydrogen sulphide. Their soft parts are blood-red as they use haemoglobin for oxygen carriers like humans. Calyptogena okutanii is one of the most famous species from Japanese waters along with its sister species C. soyoae Okutani, 1957. It is known from many chemosynthetic sites in Sagami Bay, Nankai Trough, and Okinawa Trough ranging from -750 to 2100m in water depth; and is often the dominant species especially in sediment-rich areas. The shell is very thick and covered by thick, brown periostracum which is mostly eroded in adult shells. Maximum shell length around 150mm, and shells from vent sites are usually larger than those from seep sites.
Cirsotrema rugosum (Kuroda & Ito, 1961) <br /> EPITONIIDAE<br /> Deep water, Balut Island, Philippines, 56mm, F++<br /> The "Rugose Wentletrap" is a rare wentletrap well-known for its delicate and beautiful sculpture. A carnivorous gastropod inhabiting sandy to muddy bottoms of rather deep water ranging from about -100 to -400m, it is distributed in the west Pacific and best known from Philippines and Japan. Very variable in size and can range from about 40mm to over 90mm, although average size is around 60~70mm. Sometimes seem to be confused with Cirsotrema edgari (de Boury, 1912), which is similar and also has many blade-like varices but can be easily distinguished by their wavy varices.
Penion maximus (Tryon, 1881) <br /> BUCCINIDAE<br /> Trawled, Lakes Entrance, Victoria, Australia, 240mm, F+<br /> The "Great Whelk" is a very large buccinid endemic to Eastern Australia including Tasmania. A rather light-weight shell for its size, it possesses strong nodules on shoulder which weakens on the body whorl of mature specimens. Has a thin, brown periostracum when alive; mature specimens often have slightly flared outer lip as in the specimen shown. A common carnivorous gastropod living on sandy bottoms, it is found in quite a wide bathymetric range from about -20~550m but is mostly found around -50~150m. Average shell length around 200mm, although very large specimens may exceed 260mm.
Chicomurex elliscrossi (Fair, 1974) <br /> MURICIDAE<br /> -50m, Minabe, Wakayama Prefecture, Japan, Coll. 2010, 78.1mm, F++<br /> The "Ellis Cross's Murex" is a member of genus Chicomurex native to West Pacific region, with Central Japan as its northernmost limit. A predatory gastropod living in moderate depths, it is most often found on rocky bottoms around -30~150m deep. It is best known from Kii Peninsula, Japan where it is well-known as a bycatch of lobster gillnets and rather common; specimens from other localities seem to be uncommon on the market. A quite scabrous shell, usually has extensive frills but only around the anterior half of the outer lip. Average shell length around 60~70mm, although very large specimens may exceed 85mm.
Monetaria caputdraconis (Melvill, 1888) <br /> CYPRAEIDAE<br /> -2m, Dived, Hanga Roa, Easter Island, Chile, 36.1mm, F++/F+++<br /> The "Dragon's Head Cowry" is a common cowry famous from its endemism to Easter Island and Isla Salas y Gómez, in the easternmost point of the Polynesian Triangle. A beautifully spotted species, it is distinct from the relative Monetaria caputserpentis by having black marks between teeth and having no callus in the margin. Although strictly speaking an omnivore like most cowries, it feeds mostly on algal material and is effectively an herbivorous gastropod. It is found mostly on rocky bottoms in intertidal reefs in crevices and under corals and rocks, in very shallow to shallow water less than -30m deep; being most common less than -10m deep. Average shell length around 30~35mm but it is very variable in size from dwarves as little as 15mm to giants exceeding 40mm. The population in Isla Salas y Gómez differs from Easter Island population by being smaller in size and having a much paler shell, and is usually recognised as subspecies M. caputdraconis poppei (Martin, 1989).
Brechites australis (Chenu, 1843) <br /> PENICILLIDAE<br /> Low tide, Gales Bay, Western Australia, 170.2mm, F++<br /> The "Australian Watering Pot" is a fascinating bivalve native to Australia. It is member of the peculiar watering pot family Penicillidae, members of which grow a normal shell with two valves like other clams in earlier stages of life but at one stage suddenly switches over to growing a calcareous tube made of highly organised aragonite crystals instead. This is secreted by a thin organic film covering the tube, and the animal is capable of repairing damaged tube. The early shell is not lost but still attached to the tube in opened position (see center image), proving its Bivalvia identity. It gains the common name from the fact that the bottom end (pointing downwards in life) of the calcareous tube has many pores just like a gardener's watering pot, and it can actually function like one if you put water through the top end (where siphon exits, pointing upwards in life). Debris around the tube is often caught as it grows and fuses as part of the shell, like many empty mollusc shells in the specimen depicted. It is a rather common filter feeding species living on soft bottoms of shallow water around -2~10m deep. Average tube length 170~180mm, large specimens may exceed 200mm.
Thatcheria mirabilis Angas, 1877 <br /> RAPHITOMIDAE<br /> -200m, Off Hamamatsu, Shizuoka Prefecture, Japan, 92mm, F++<br /> The aptly named "Japanese Wonder Shell" is one of the most exiquitely shaped gastropod known. It is said to have inspired many artists and architects, for example Frank Lloyd Wright based the design of Guggenheim Museum on this shell. First described from a Japanese shell brought to George Angas by Charles Thatcher, Angas had great difficulties working out its taxonomic affinities and placed it in a new genus honouring the finder. The holotype is apparently badly damaged and papier-maché was used to repair the outer lip. The particularly angular and scalariform shoulder combined with an elegant shape makes this species truly unique. So unique that until more were found around 1930s, many (e.g., George W. Tryon) thought it was an extreme freak form of something. For many years it was a classic rarity known only from Japan but now it is known to be fairly common in the Pacific ranging from Japan to as far as Western Australia. Part of its early scarcity can be explained by the fact that it is a predatory gastropod inhabiting sandy to muddy bottoms of quite deep water around the depths of -50~400m. Shells of live specimens are even more lovely with a pink hue which fades rapidly after death. Although long considered a turrid, with the recent taxonomic revisions of Turridae it is now placed in Raphitomidae. Average shell length around 70~80mm, very large specimens may exceed 100mm.
Homalocantha anomaliae Kosuge, 1979 <br /> MURICIDAE<br /> Philippines, 47.8mm, F++<br /> The "Anomalous Murex" is a great deep-water rarity only known from Central Philippines. With very loosely coiled whorls and fragile wide-ending spines resembling ginkgo leaves, it is a very peculiar member of the genus Homalocantha. The first specimen was collected by tangle nets in Davao Gulf, and was such a strange shell that it was considered an extreme freak of Homalocantha scorpio (Linnaeus, 1758) until more specimens were found. Adult specimens in good condition are very rare, and spines in earlier whorls may be retained in very top specimens. It is famous for the large number and wide variety of fakes and doctored specimens made in Philippines and extra care must be taken before purchasing a specimen. Very variable in spine length and development. Most specimens are caught with tangle nets around depths of -100~500m. Average shell length around 42~47mm, giant specimens may exceed 60mm.
Homalocantha fauroti Jousseaume, 1888<br /> MURICIDAE<br /> -8m, Eilat, Israel, 47mm, F++<br /> The spectacularly spined "Faurot's Murex" H. fauroti Jousseaume, 1888 is a muricid ranging from Red Sea to Mascarene Basin. It was once regraded as a synonym of H. anatomica -- a very widely distributed murex found across the Indo-Pacific region, but now considered by many to be a separate species. It is a carnivorous murex feeding mostly on bivalves common on coralline reefs in shallow water of about -2~40m deep. Average shell length around 40~50mm, although very large specimens exceed 60mm.
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