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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.

Coluzea groschi Harasewych & Fraussen, 2001<br /> COLUMBARIIDAE<br /> -250~350m, By lobster traps, Off Zavala (aka Quissico), Mozambique, 37.2mm <br /> <br /> An elongate and petite columbariid, the "Grosch's Pagoda Shell" appears to be endemic to southern Mozambique, most specimens have been taken between Zavala (i.e., Quissico) and Zavora. It is characterised by a very highly spired, fusiform shell with a single row of short, open spines on the periphery, combined with an almost complete lack of axial ribbing. At a glance it appears close to C. berthae (Monsecour & Kreipl, 2003), but that species always carry strong axial ribbing and is much larger (often exceeding 80mm in shell length). Its general outline is quite similar to Fustifusus pinicola (Darragh, 1987) from New Zealand, which also carry clear axial ribbing and has a distinctive colour pattern consisting of reddish flammules lacking in C. groschi. A carnivorous and predatory gastropod feeding on tube-dwelling polychaetes, it inhabits sandy to muddy bottoms of rather deep water around -100~300m. A very rare species, it appears on the international shell trading market only once in a blue moon. Typical shell length around 30mm, extremely large specimens may exceed 40mm. The original seven specimens were brought to the attention of Jerry Harasewych and Koen Fraussen by the Amorim family, shell collectors living in Mozambique but originally from Portugal. Their interest in shell collecting was mentored by Mr. J. Kurt Grosch, for whom this species was named.
Coluzea distephanotis (Melvill, 1891) <br /> COLUMBARIIDAE<br /> -300m, Trawled, Timor Sea, 74.3mm <br /> <br /> A scarcely seen pagoda shell, Coluzea distephanotis is a strikingly sculptured columbariid ranging from North West Cape, Australia to Arafura Sea. It is characterised by a prominent "double-keel" sculpture on the early whorls formed by the periphery and an equally strong spiral cord just anterior of it, less obvious beyond the eighth whorl due to the spiral cord decreasing in relative strength. The specific epithet 'distephanotis', meaning 'double wreath', refers to the "double-keel" sculpture. It is quite variable in other aspects of the sculpture, especially strength of the axial ribbing and the development of the short open spines on the periphery. A carnivorous and predatory gastropod feeding on tube-dwelling polychaetes, it inhabits sandy, rubbly, or muddy bottoms of rather deep water around -300~450m. It is a very rare species and is almost never offered on the shell trade market. Typical shell length around 65mm, very large specimens are known to exceed 75mm. The original description was actually based on a juvenile specimen 18.9mm in shell length, said to have been dredged from 31m deep in Torres Straits off New Guinea. Though all conchological characteristics match well, this locality data is considered erroneous as it is far too shallow for genus Coluzea and is quite some distances outside of the confirmed distribution range.
Admete tenuissima Okutani & Fujikura, 2002 <br /> CANCELLARIIDAE<br /> -5313m, Sanriku Escarpment Cold Seep Site, Japan Trench, Japan, 15.5mm<br /> <br /> The "Glassy Nutmeg" is an extremely delicate cancellariid endemic to the Japan Trench, characterised by densely packed fine spiral threads numbering about 40 on the body whorl. An abyssal species inhabiting exceptionally deep water around -5300~5800m, virtually nothing is known about its biology. So far its distribution appears to be restricted to chemosynthetic ecosystems fueled by cold methane seepage, resulting from tectonic activities in the trench. Both radula and operculum are lacking, and it is presumably a suctorial carnivore feeding on other invertebrates or their eggs. Given the extreme depths it occurs at and the restricted habitat, it has only ever been collected by research submersibles and remotely operated vehicles. In addition, it seems to be a rare species in its natural habitat too. Typical shell length around 15mm, very large specimens may exceed 20mm.
Fulgurofusus nanshaensis Zhang, 2003 <br /> COLUMBARIIDAE<br /> -400~600m, Trawled, Northern part of Spratly Islands, South China Sea, 2016, 60.5mm <br /> <br /> The "Nansha Pagoda Shell" is a delicate columbariid that is apparently endemic to the Spratly Islands, South China Sea. Probably the rarest of all pagoda shells known from South China Sea, it was described from a single specimen taken from 480m deep off Alexandra Bank in the western edge of Spratly Islands and virtually no specimens have emerged since. Although described as a Fulgurofusus, morphology of the protoconch and the aperture suggests that it should actually be placed in the genus Columbarium. Characterised by a continuous peripheral keel with an irregular edge, the only species it may be mistaken for is Columbarium pagodoides (Watson, 1882) with a similar keel but the protoconchs are so drastically different that there is no room for real confusion. Colouration of the shell is usually whitish. Inhabiting sandy to muddy bottoms around 400~600m deep, nothing is known about its feeding habits but it is almost certainly a predator of tube-dwelling polychaetes like other members of Columbariidae. Typical shell length around 50mm, large specimens as the one depicted may exceed 60mm. It is named after Nansha Islands, the Chinese name for Spratly Islands.
Annachlamys reevei (Adams in Adams & Reeve, 1850) <br /> PECTINIDAE<br /> -20~25m, Off southwest Nishio (ex. Isshiki-cho), Mikawa Bay, Aichi Prefecture, Japan, 1978/vi, Ex-coll. Shoichiro Hayashi, 47.4mm <br /> <br /> An extremely picturesque and colourful pectinid, the "Reeve's Scallop" ranges from central Japan to the Philippines and is one of the most sought-after pectinids of all. The shell is little-varied in form and always with white background, but the pattern is very variable. Though best known for patches or 'clouds' of rich blood-red, these 'clouds' can vary also from pinkish purple to orange to brown and differ greatly in distribution among individuals. The interior of the valves are usually also tinted in the same colouration as the exterior, though sometimes they are white. The left valve is usually much more colourful than the right valve, for both the exterior and the interior. A filter-feeding bivalve, it inhabits sandy bottoms of moderate depths around -10~80m. A rare species especially in fine condition, most specimens seen on the marke originate from either Japan or the Philippines. Typical shell length around 40mm but extremely large specimens may exceed even 70mm. Sometimes confused with other Annachlamys species but in fact it can be easily distinguished as it is the only species in the genus to bear ribs on the ears.
Columbarium hystriculum Darragh, 1987 <br /> COLUMBARIIDAE<br /> -300m (-1000ft), Trawled, Off Townsville, Queensland, Australia, 83.6mm <br /> <br /> One of the most elaborately sculptured pagoda shells, Columbarium hystriculum is a captivating turbinellid endemic to northern Queensland, Australia. Characterised by a strongly double-spined periphery and one or two further spinous spiral cord anterior to the clearly defined anterior caina, it is impossible to mistake it for any other described species as the most similar congener C. harrisae Harasewych, 1983 only carry a single row of spines on the periphery. The siphonal canal is long, with the posterior half carrying rather sparse but strong spines. The protoconch begins in a sharp tip instead of being bulbous like most other Columbarium species due to the very early part of the first whorl formed in the egg being chitinous (not calcified) and decidous upon hatching. An uncommon carnivorous and predatory gastropod feeding on tube-dwelling polychaete worms, it inhabits soft bottoms of moderately deep water around -200~400m. Typical shell length around 70mm, extremely large specimens may exceed 95mm.
Columbarium pagoda (Lesson, 1831) <br /> COLUMBARIIDAE<br /> -150m, Trawled, Off Amakusa, Kumamoto Prefecture, Japan, 80.5mm <br /> <br /> Undoubtedly the most famous of all Columbariidae species the "First Pagoda Shell" is an utmostly elegant turbinellid mainly distributed from Japan to East China Sea, with some records from as far as South China Sea. It is characterised by a bulbous protoconch, a single row of peripheral spines directed posteriorly, and a very long siphonal canal; but is a very variable species. The peripheral spines vary greatly in frequency and length, the name stellatum Habe, 1953 (now treated as a synonym) was given to specimens with more horizontally directed spines. The anterior carina is usually clearly defined with a single row of spines but many specimens develop three to four rows and has only a weak carina, such specimens were given the name costatum Shikama, 1963 (now treated also as a synonym). Furthermore, the name nakayasui Habe, 1953 (again, now treated as a synonym) was given to South China Sea specimens which tends to be smaller and have strongly curved spines. The posterior part of the siphonal canal is usually spinous but the degree vary greatly among individuals. A carnivorous and predatory gastropod feeding on tube-dwelling polychaetes inhabiting sandy to muddy bottoms, it is one of the shallowest Columbariidae species with a general bathymetric range around -50~200m (although they can rarely be found as shallow as -30m). One of the most common and readily available pagoda shells, it is very popular with collectors but perfect specimens are actually quite hard to get. Typical shell length around 65mm, extremely large specimens may exceed 90mm. It was named 'pagoda' as its spire reminded the author of Japanese pagoda architecture, and it gains its common name from the fact that it was the first pagoda shell to be formally described.
Coluzea eastwoodae (Kilburn, 1971) <br /> COLUMBARIIDAE<br /> -100m, Trawled, Off Durban, KwaZulu-Natal, South Africa, 81.2mm <br /> <br /> The "Eastwood's Pagoda Shell" is a graceful, frosty coloured columbariid native to the southwestern Africa with an approximate distribution ranging from Mozambique to South Africa, including Madagascar. It is characterised by a sloped shoulder with a single row of spines on the periphery directed either horizontally or slightly anteriorly, together with a clearly defined anterior carina. There is no significant sculpture between the suture and the periphery; the siphonal canal is moderately long with no spines. The peripheral spines are very variable in strength and development among individuals. A carnivorous and predatory gastropod feeding on tube-dwelling polychaetes, it inhabits soft bottoms and has a rather wide bathymetric range around -100~600m deep. Although a common species mostly due to its relatively shallow habitat for the family Columbariidae, obtaining a high quality live-taken specimen is not an easy task as most specimens are dead-taken and damaged. Typical shell length around 70mm, extremely large specimens may exceed 90mm.
Columbarium suzukii Habe & Kosuge, 1972 <br /> COLUMBARIIDAE<br /> Trawled in deep water, Off Nha Trang, Khanh Hoa Province, Vietnam, 2000, 98.5mm <br /> <br /> The "Suzuki's Pagoda Shell" is a large and attractively spinous columbariid endemic to South China Sea, ranging from southwestern China to Vietnam. It is characterised by a thick, robust shell with two rows of strong spines above the suture; the anterior row is weaker with spines directed anteriorly while the more posterior peripheral row is stronger with the spines directed posteriorly. More anterior to these two rows, on the body whorl there is a clear anterior carina that lacks obvious spines. The siphonal canal is on the short side for genus Columbarium and carry several rows of spines on the posterior half. A carnivorous and predatory gastropod feeding on tube-dwelling polychaete worms, it inhabits sandy to muddy bottoms of rather deep water around -300~500m. An uncommon species, vast majority of specimens originate from fishery by-catches of Nha Trang port, Vietnam. Typical shell length around 90mm, extremely large specimens may exceed 110mm. It is named in honour of Mr. Masaji Suzuki, a greengrocer wholesaler in Tokyo who imported many new species of South China Sea molluscs to Japan in the 1970s leading to their formal taxonomic description, including this species.
Another one from Sagami Bay! :)<br /> <br /> Conchocele bisecta (Conrad, 1849) <br /> THYASIRIDAE<br /> -856m, Off Hatsushima, 35°0.0'N 139°13.3'E (methane seep site), Sagami Bay, Shizuoka Prefecture, Japan, 102.8mm <br /> <br /> The "Giant Cleftclam" is an extremely large (probably the largest extant) thyasirid very widely distributed in the northern Pacific Ocean, ranging from East China Sea to Russia to Oregon, USA. It is a chemosymbiotic bivalve hosting both methane and sulfur oxidising endosymbionts in a much enlarged gill, and relies on these for energy. Although it is a well-documented member of the Pacific methane seep community often co-occuring with other chemosymbiotic bivalve genera such as Calyptogena and Acharax, it is also found in reducing sediments rich in methane and sulfides outside seeps. It occurs across a wide bathymetric range from -50m down to more than -1500m deep. Both the specific epithet and common name comes from the deep ridge or cleft on the posterior end of the shell, a feature common in Thyasiridae but most prominent in genus Conchocele. The shell shape changes drastically throughout life stages; the anterior shell margin protrudes beyond the beak in young specimens, but becomes flat to strongly concave in adults. Adult shells are usualy also more elongated (though those from Japan and southwards appear less so, as shown) and much thicker. Typical shell length is around 90mm but extremely large specimens exceeding 165mm are known. Recent specimens are very rare due to its restricted habitat, especially large live-taken ones, although virtually identical Cenozoic fossils are not uncommon. Conchocele disjuncta Gabb, 1866 described from Pliocene fossil of California, USA is widely regarded as a synonym.
Off to a cruise on-board JAMSTEC R/V "KAIMEI" to explore methane seeps in Sagami Bay! Here's a rare one from the area I will be exploring! :) <br /> <br /> Neptunea acutispiralis Okutani, 1968 <br /> BUCCINIDAE<br /> -1120m, Off Hatsushima, 35°0.0'N 139°13.5'E (methane seep site), Sagami Bay, Shizuoka Prefecture, Japan, 102.8mm <br /> <br /> A rarely seen neptune shell endemic to Japan, Neptunea acutispiralis has a restricted distribution from Sagami Bay to northern Izu Islands (to Miyake Island). It is characterised by a tall and voluminous spire, with much shallower suture compared to similar Neptunea species such as Neptunea intersculpta (Sowerby III, 1899). The sculpture consists of spiral cords of a quite uniform strength; the interior is pure white apart from the area close to outer-lip which may be tinted orange or yellow. A predatory and scavenging gastropod, it inhabits mostly muddy bottoms of deep water between -850~1400m in depth. It is best known from methane seeps off Hatsushima, Sagami Bay, where it is found in low densities in colonies of chemosymbiotic bivalves Calyptogena and Bathymodiolus. It lives side-by-side with another buccinid Buccinum yoroianum Ozaki, 1958 (population from Sagami Bay seeps were previously known as B. soyomaruae Okutani, 1977 before it was synonymised with B. yoroianum), both species apparently feed on the bivalves. Typical shell length around 100mm, although very large specimens may exceed 130mm. Due to the complete lack of deep-water bottom fishing in Sagami Bay there is no commercial means of obtaining this species (and many other species) and as a result it is extremely rare in collections. The type material was collected by research trawling conducted by R/V Soyo-Maru operated by the National Research Institute of Fisheries Science, Japan; its recent records are almost completely restricted to specimens taken by research trawling and submersible dives.
Adamussium colbecki (E. A. Smith, 1902) <br /> PECTINIDAE<br /> Caught by fish hook from the ship, Under the ice slope, 14.5km off King Edward VII Land, Marie Byrd Land, Antarctica, 2009/i, 83.0mm <br /> <br /> With a circum-Antarctic distribution including off islands of the Scotia Arc and South Sandwich Islands, the "Antarctic Scallop" is the only large pectinid in Antarctica. Its distribution is apparently disjunct and densities vary greatly among sites, with some sites harbouring an impressive density of over 150 individuals per square metre. As it has a paper-thin and fragile shell (typically a feature seen only in deep-water pectinids), it has been suggested to require calm areas well-protected from wave action and current, hence the disjunct distribution. Although most populations are fround around -3~100m deep, it is also occasionally found at much deeper on the continental shelf to over -1000m deep in low densities. A suspension feeder, it is usually found on soft sediment bottoms and although capable of swimming by opening and closing its shells, it spends most of the time sitting on the seabed. Its development and growth is much slower than pectinids living in warm waters, requiring five to seven years of growth before sexual maturity. Juveniles are known to tie themselves to adults using byssus threads and use them as substrate. The juveniles benefit by receiving increased organic particle intake through the water movement generated by the adults through feeding or moving. The adults also use byssus threads to attach to hard substrates in areas experiencing considerable current. Typical shell length around 70mm, extremely large specimens are known to exceed 100mm. It is the only member of the genus Adamussium, established by the German malacologist Johannes Thiele specifically to house this unique species. Although overall a common species in the Antarctic, it is a rather rare species on the shell trade market due to the difficulty of acquiring material from Antarctica.
Desbruyeresia chamorrensis Chen, Ogura & Okutani in Chen et al., 2016<br /> PROVANNIDAE <br /> HOLOTYPE (UMUT RM32350)<br /> -2915m, Summit Site (serpentinite-hosted seep), South Chamorro Seamount (13°46.911’N, 146°00.219’E), JAMSTEC R/V Natsushima cruise NT12-23, ROV Hyper-Dolphin Dive 1434, 2012/ix/10, 7.7mm <br /> <br /> Discovered from a cold seep in the Mariana Forearc, Desbruyeresia chamorrensis is a heavily sculptured provannid and the first member of its genus found outside hydrothermal vent ecosystems. A deposit-feeder, it is so far only known from three specimens collected from 2915m deep on the South Chamorro Seamount, an active mud volcano rich in serpentine. Serpentine minerals in the mud are formed from by ultramafic rocks reacting with fluids from subducting plate through exothermic serpentinisation processes, which generate a significant amount of compounds such as methane. These compounds can then be used by certain microorganisms to drive chemosynthesis and thereby powering chemosynthetic ecosystems like vents or seeps. Although hydrothermal vent fluids are typically acidic, fluids produced by serpentinisation are usually alkaline. Desbruyeresia chamorrensis is the first endemic gastropod formally described from such environments, although other undescribed snails are known from other sites. Typical shell length around 7.5mm, the largest specimen known is the holotype shown here which is 7.7mm. It is distinguished from all other described congeners by having much more numerous (17–20) axial ribs on the teleoconch and a broad shell for the genus (shell width to height ratio 0.6–0.65). Although only three specimens have been collected so far, it is likely a common species in the South Chamorro Seamount seep site and further expeditions to this site should be able to recover further examples. <br /> <br /> Chen C, Ogura T, Hirayama H, Watanabe HK, Miyazki J, Okutani T (2016). First seep-dwelling Desbruyeresia (Gastropoda: Abyssochrysoidea) species discovered from a serpentinite-hosted seep in the southeastern Mariana Forearc. Molluscan Research. DOI:10.1080/13235818.2016.1172547<br /> http://www.tandfonline.com/doi/abs/10.1080/13235818.2016.1172547
Nucella freycinetii (Deshayes, 1839) <br /> MURICIDAE<br /> -250m, Trawled by commercial fisherman, From hardpan bottom among rubble, Off Monbetsu, Hokkaido, Japan, 2015, 63.4mm <br /> <br /> An extremely variable muricid, Nucella freycinetii is a large dogwhelk ranging from northern Honshu, Japan to Kamchatka Peninsula, Russia. The sculpture varies from virtually smooth with only subtle fine striations to tall and elaborate wavy frills (as shown). This is undoubtedly correlated with the environment, with specimens in calmer and deeper waters generally having stronger sculpture. The spire height is also rather variable, but this difference seems to be randomly distributed among populations. A carnivorous and predatory gastropod inhabiting hard rocky bottoms, it appears to have a wide bathymetric range from intertidal down to about -200m deep. Although a common species across its range, the extremely frilled form shown here is mostly restricted to waters deeper than -100m and is rarely seen. Typical shell length around 45mm, extremely large specimens may exceed 70mm. Due to its variability some synonymous names have been proposed in the past, such as N. alabaster (Pilsbry, 1907) and N. saxicola (Valenciennes, 1846). The name N. alabaster refers to heavily sculptured specimens with taller spires and some authors treat it as a subspecies, N. freycinetii alabaster.
Scelidotoma vadososinuata (Yokoyama, 1922) <br /> FISSURELLIDAE<br /> -110~120m, By gillnet, Off Yagi Port, Hirono-cho (Ex Taneichi-machi), Iwate Prefecture, Japan, 2015/x, 52.2mm <br /> <br /> Scelidotoma vadososinuata is a moderately large fissurellid endemic to the Japonic Province with the nominal subspecies native to northern Japan and another subspecies S. v. hoonsooi Choe, Yoon & Habe, 1992 known from Korean waters, which supposedly have a much more depressed shell with more distinct imbricated radial sculpture. It is a rare species, partly due to it living well-attached on hard rocks beyond usual diving depths, makeing it difficult to collect. A grazing gastropod living attached to hard substrates and feeds on algae, it inhabits rather deep water at around -50~200m. Typical shell length around 40mm, extremely large specimens may exceed 60mm. Large specimens in good condition are much sought-after and prized; younger shells less than 20mm in length usually inhabit shallower water and are collected more often. It was first described in the genus Emarginula then soon moved to Tugalina and remained there for a long time before being moved again to Scelidotoma, its the current genus. The Japanese name ('Wamei') "Koshidaka-Saruawabi" is named in honour of the ship Koshidaka-maru which collected the material for description. It is rather similar to the congener S. gigas (Martens, 1881) which lives at a shallower depth and is often confused with it. They can be distinguished by S. gigas having a much more elongate and lower shell, as well as generally coarser sculpture. The foot of S. gigas is of a darker colouration than S. vadososinuata (usually red vs. orange), and the mantle edge is black unlike that of S. vadososinuata which is the same colour as the foot.
Septa occidentalis (Mörch, 1877) <br /> RANELLIDAE<br /> Dived in shallow water, Off Boca Raton, Florida, U.S.A., 27.2mm <br /> <br /> The "Pale Triton" is a small but lovely ranellid with an extremely wide distribution in subtropical and tropical waters around the globe. Compared to other species in genus Septa, it has a more stout shell with rougher surface. When alive, the shell is covered entirely by a thick periostracum with finely reticulate surface. An uncommon carnivorous and predatory gastropod, it inhabits rubble bottoms of shallow water from low intertidal down to about -50m. A small-sized Septa species, its shell length averages at around 25mm while the largest individuals may exceed 40mm. The Hawaiian population was recognised for some time as a separate subspecies S. occidentalis beui (Garcia-Talavera, 1985), but is now considered a synonym by most. In the western Pacific there appears to be a long confusion between this species and the name Septa limbata (Röding, 1798), with many specimens of S. occidentalis labelled as S. limberta. The issue with the name S. limbata was in fact discussed and solved by Alan Beu in 1986, who noted that the figure cited in the description is in fact S. flaveola (Röding, 1798). As S. limbata and S. flaveola was described in the same work by Röding and S. flaveola was in prevailing use, Beu selected the name S. flaveola to be the senior synonym as first reviser and designated a single specimen to be the neotype for both names. In addition, Beu clarified that the only modern use of the name S. limbata (as Tritonium limbatum) was actually applied to a mis-identified specimen of Monoplex gemmatus (Reeve, 1844). Specimens of Septa from western Pacific in collections identified as S. limbata (often mis-spelt as S. limberti; Japanese name Hime-Jyuseira) usually have nothing to do with the name S. limbata but are in fact mostly S. occidentalis and sometimes either M. gemmatus or M. mundus (Gould, 1849). Although merely a speculation, treating the western Pacific populations of S. occidentalis under a different name probably roots in disbelief that the same species is shared across Pacific and Atlantic Oceans.
Neptunea costaria Fraussen & Terryn, 2007 <br /> BUCCINIDAE<br /> -500~550m, Off Pacific coast of Iturup Island, Kuril Islands, 2014/iv, 72.3mm <br /> <br /> An attractive neptune with numerous deeply carved spiral ridges, Neptunea costaria is a cold-water buccinid apparently endemic to the southern Kuril Islands. Although originally described as Costaria borealis Golikov, 1977, Koen Fraussen and Yves Terrynafter rightly moved it to genus Neptunea in their "A Conchological Iconography: Family Buccinidae, Genus Neptunea" (2007). A problem caused by this genus movement was that its scientific name became a junior homonym of Neptunea borealis (Philippi, 1850) and thus had to be replaced. The two authors therefore proposed the current replacement name, taken from the original genus assigned by Golikov. A carnivorous and predatory gastropod, it inhabits soft bottoms of rather deep water around -400~600m. It is a very rarely seen species, mostly due to its difficult-to-access distribution range. Typical shell length around 60mm, very large specimens may reach 80mm. It is perhaps most similar to Neptunea oncodes (Dall, 1907) ranging from the northern Kuril Islands to Bering Sea, but can be distinguished by its stronger spiral cords and shallower suture.
Coluzea icarus Harasewych, 1986 <br /> COLUMBARIIDAE<br /> Trawled from deep water, Off Broome, Western Australia, Australia, 72.4mm <br /> <br /> Characterised by a pure white shell with a single prominent peripheral keel, the "Icarus Pagoda Shell" is a delicate columbariid species apparently endemic to the northern part of Western Australia, Australia. The spines on the keel is variable in which direction they point to, from upwards to slightly downwards, as well as in their strength. Although a very attractive species, it is very uncommon on the market due to limited supply like other pagoda shells from Western Australia. A carnivorous and predatory gastropod feeding on polychaete worms like other Columbariidae species, it inhabits soft bottoms of upper continental shelf at around -400~600m deep. Typical shell length around 60mm, extremely large specimens may exceed 75mm. It is actually named after Icarus, son of Daedalus, from Greek mythology who famously attempted to escape from Crete by the means of wings made from wax. Icarus failed to follow Daedalus' instructions of not to fly too close to the sun, and fell to the sea due to the wings melting. The reason for naming this species after Icarus was not made clear in the original description, however.
Coluzea altocanalis Dell, 1956 <br /> COLUMBARIIDAE<br /> -600m, Trawled, Chatham Rise, New Zealand, 80.0mm <br /> <br /> With prominent spiral keels carving out a spire of utmost elegance, Coluzea altocanalis is surely one of the most attractive pagoda shells of all. An endemic species of New Zealand, it inhabits muddy bottoms of deep water around -400~1000m in the upper continental slope of North Island, South Island, as well as along the Chatham Rise. A carnivorous and predatory gastropod, it primarily feeds on polychaete worms like other members of Columbariidae. Perhaps one of the rarest and most sought-after Coluzea species, it is very difficult to obtain in fine condition. Generally a little-varied species, in juvenile specimens the peripheral keel appears even more prominent due to the other keels being less developed than in adult specimens. Although the typical shell length is around 80mm, the largest specimens are known to exceed 125mm, making it likely the largest of all pagoda shells.
Adelomelon riosi Clench & Turner, 1964 <br /> VOLUTIDAE<br /> -200m, Trawled, Ilha de São Sebastião, São Paulo State, Brazil, 255.9mm <br /> <br /> A large volutid of solemn dignity, the "Rios' Volute" is a South American volitid ranging from São Paulo State, Brazil to Mar del Plata, Argentina. Once a great rarity, today it has become much easier to acquire and is only uncommon. It is very susceptible to encrustation damage from polychaetes and other sessile invertebrates, however, and clean specimens of good size are therefore not easy to obtain. Quite variable in breadth compared to height, some specimens are rather elongate and others are quite stout; though the whorls are always strongly convex. The subgenus Weaveria was once erected for just this species based on the thick and deciduous periostracum, surface without zigzac-line pattern, and the strongly convex whorls. In spite of this, it is now clear that it often does carry zigzac pattern especially when young and some other Adelomelon species also have the same type of periostracum. Weaveria was therefore recently synonymised with Adelomelon. A carnivorous gastropod inhabiting soft bottoms of rather deep water around -100~500m, it apparently feeds primarily on echinoderms. Typical shell length around 230mm, extremely large specimens may reach 350mm.
Buccinum kurilensis Golikov & Sirenko, 1988 <br /> BUCCINIDAE<br /> -450~470m, Trawled, Off Pacific coast of Urup Island, Kuril Islands, 2016/vi, 74.0mm <br /> <br /> A refined whelk with numerous spiral cords and straw-coloured periostracum, Buccinum kurilensis is a cold-water buccinid endemic to the southern Kuril Islands. Two of the many spiral cords are thicker than the rest and are slightly raised to make the spire appear angulated, the extent of which is somewhat variable among individuals. The siphonal canal is often slightly recurved in large specimens. A carnivorous and possibly scavenging gastropod, it inhabits soft bottoms of deep water around -400~700m. An extremely rare species partly due to its difficult to access and narrow distribution range, it virtually never appears on the shell trade market. It is a medium-sized Buccinum with a typical shell length around 60mm, although extremely large specimens may reach 80mm.
Hysteroconcha dione (Linnaeus, 1758) <br /> VENERIDAE<br /> -3~4m, Dived, Adícora, Paraguaná Peninsula, Falcón Municipality, Venezuela, 52.7mm <br /> <br /> An extraordinary venerid, the delicately lavender "Royal Comb Venus" is one of few non-pectinoid bivalves to possess significant long spines on the shell. The spines projects posteriorly in two rows along a ridge running from the posterior margin to the umbo, and are thought to have a protective function guarding the soft siphon from predatory fishes. Although locally a common species the spines are fragile and easily broken, vast majority of specimens have no intact spines left. Specimens with well-preserved spines (as shown) are therefore quite rare and much sought-after by collectors. It is a western Atlantic species ranging from eastern Mexico to Venezuela, most specimens apparently originate from Venezuela. A filter-feeding and bivalve, it lives burried in sandy bottoms of shallow water from low intertidal zone down to about -10m deep. Typical shell length around 30mm excluding the spines, extremely large specimens may reach 50mm. When describing this species, Linnaeus famously alluded the view from umbo to human female genitalia, which he saw great similarity between, and wrote the description using obscene sexual terms. The obscenity actually increased in the description included in his later work "Fundamenta Testaceologiae" (1771) and was criticised by other naturalists such as Emanuel Mendes da Costa. The specific epithet 'dione' apparently refers to the goddess Dione, mother of Venus, in Greek mythology. Initially it was placed in the genus Venus, later in Pitar for many years, before its current placement in Hysteroconcha was accepted. Quite similar in appearance and often confused with its eastern Pacific congeners H. lupanaria (Lesson, 1831) and H. multispinosa (Sowerby II, 1851). The larger H. lupanaria has much longer spines on average but fewer in number, plus the concentric ribs are flat and not raised in the posterior half of the shell; the brown-coloured H. multispinosa is smaller and has even denser spines than H. dione.
Alcithoe fissurata (Dell, 1963) <br /> VOLUTIDAE<br /> -450~500m, Trawled, Off Motiti Island, Bay of Plenty, North Island, New Zealand, 2015/xii, 176.8mm <br /> <br /> Alcithoe fissurata is an elegant volutid endemic to the northern half of North Island, New Zealand. Three subspecies are currently recognised, differing in shell morphology as well as geographic and bathymetric ranges. The moderately rare nominal and eastern subspecies A. f. fissurata (shown) ranges from Cape Brett to Bay of Plenty and is characterised by a thin and lightweight shell with clearly stepped spire, found in rather deep water around -350~700m. It is also the largest subspecies with the average shell length around 180mm and the largest specimens exceeding 215mm. The northernmost subspecies A. f. crassa Bail & Limpus, 2005 is only known from the northern tip of North Island to Three Kings Islands and is characterised by a wider, thicker, heavier shell attaining a similar size as the nominal subspecies. It occurs at a very shallow depth around -50~80m, and is very rare (described from less than a dozen specimens). The western subspecies A. f. elegans Bail & Limpus, 2005 ranges from Ahipara to Cape Maria van Diemen and is characterised by a smooth, less stepped spire, together with a much smaller shell (averaging at around 100mm shell length, although very large specimens reaching 170mm are supposedly known). It occurs at moderately deep water around -250~350m and is extremely scarce, only two specimens were known at the time of description and few more have been collected since. Future investigations may prove that these three subspecies are each worthy of species rank in their own right. All are carnivorous and predatory gastropods inhabiting sandy to muddy bottoms. It was originally placed in the subgenus Palomelon within the genus Pachymelon, until the recent synonymisation of Palomelon with Alcithoe. Pachymelon remains valid but is a fossil genus with only one currently accepted species, Pachymelon amoriaformis (Marwick, 1926) from Early Miocene which is a distinctive medium-sized (around 70mm in shell length) species with an unusually large number of very fine columellar plaits (6~8). All other extant and extinct species previously referred to Pachymelon have been moved to Alcithoe and the need of retaining the genus Pachymelon for P. amoriaformis alone is quite debatable.
Gaza superba (Dall, 1881) <br /> MARGARITIDAE<br /> -700m, Trawled, Off Mississippy River Delta, Gulf of Mexico, Louisiana, USA, 36.4mm <br /> <br /> Characterised by a gorgeously iridescent golden sheen, the "Superb Gaza" is a much celebrated rarity ranging from Gulf of Mexico through to the Caribbean Sea. The apex is deciduous (i.e., naturally falls off with growth) and is thus always missing in adult specimens. The outer layer of the shell is slightly variable in colouration from golden to olive and beige, the inner layer is highly nacreous and pearly. The diet and feeding mechanism of genus Gaza is not well-known in general, but sand and mud have been found in the digestive tract suggesting they are detritivores that swallow detritus and digest the organic matter within. A deep-water species, it inhabits sandy to muddy bottoms around -400~900m in depth, mostly specimens are collected from about -600m deep. Typical shell diameter around 35mm with the very largest specimens reaching 45mm. It is conchologically similar to the congener Gaza olivacea Quinn, 1991, another large Gaza that reaches a similar size, and is often confused with it. However, it can be easily distinguished by its lower spire and the umbilicus being only half-covered by callus (always nearly completely covered in G. olivacea).
Spondylus darwini Jousseaume, 1882 syn. pickeringae Lamprell, 1998 <br /> SPONDYLIDAE<br /> -20~30m, Dived in coral reef, Ras Abu Galum, Dahab, Sinai Peninsula, Egypt, 2004, 136.3mm <br /> <br /> Perhaps much better known by the now synonymised name Spondylus pickeringae, S. darwini is a large spondylid with a limited distribution range restricted to Red Sea and Gulf of Aqaba. Although the name S. darwini has been long attributed to an Indo-West Pacific species with dense spines following Lamprell and other authors, recent research suggest that this is a mistake and the densely spined species is actually S. asperrimus Sowerby II, 1847. The true S. darwini, which Jousseaume described with unknown locality, is deemed to be one and the same as S. pickeringae. As S. darwini was described much earlier, it is the senior synonym and takes precedence as the scientific name. Due to their extremely variable morphology the taxonomy of Spondylidae is constantly in a status of flux and often even chaos. Perhaps only genetic evidence in the future will reveal the true relationships among the various names of Spondylus, but of course finding specimens that can be concretely identified to those names to sequence is another issue. A filter-feeding species, it is found around -5~40m deep in coral reefs and lives a sessile life cemented on dead corals. Although locally not uncommon, it is quite rare on the shell trade market due to its inaccessible distribution. Characterised by strikingly contrasting white spines and reddish interstices, like many spondylids it is very variable in spine length and thus not easy to find a specimen with well-developed spines in good condition. Typical shell length around 110mm, extremely large specimens may exceed 150mm. The specific epithet is dedicated to Charles Darwin and the better known junior synonym was named for Joan Pickering of the Natural History Museum, London.
Morum macandrewi (Sowerby III, 1889) <br /> HARPIDAE<br /> Off Sakai, Minabe-cho, Wakayama Prefecture, Japan, 1993/i/31, Coll. Tadashi Ookoba, 41.8mm <br /> <br /> Characterised by relatively few but strongly nodulous and raised varices, the "MacAndrew's Morum" is a symbolic harpid of the Japonic province ranging from Chiba Prefecture, Japan to East China Sea. A classic rarity and much sought-after by Japanese and global collectors alike, even dead shells are rare and live-collected specimens are extremely scarce. It is a carnivorous and predatory gastropod and inhabits coarse sand bottoms of moderate depths around -30~200m. Very rarely it is found beached after storms, and recently a few live individuals have been sighted by lucky divers. Despite the recent staggering increase in the availability of many species inhabiting East China Sea due to Chinese trawlers the availability of this species has remained virtually unchanged, suggesting that its distribution centre is in Japan and is truly rare in East China Sea. Typical shell length around 40mm, extremely large specimens may exceed 55mm.
Laevichlamys boninensis (Dijkstra & Matsukuma, 1993) <br /> PECTINIDAE<br /> -15m, Dived on coral under rocks, Chichijima Island, Ogasawara Islands, Tokyo, Japan, 2012/vi/21, 43.5mm <br /> <br /> A peculiar pecten of erratic beauty, Laevichlamys boninensis lives attached by byssus when young with an ordinary Chlamys-like shell but upon reaching a certain size (around 15-20mm) abruptly changes to a entirely sessile lifestyle and irregular growth by sementing the right valve to hard substrate, mostly corals. An endemic species of Ogasawara Islands (also known as Bonin Islands), Japan, it was first discovered as a single right valve by Dr. Katsura Oyama in 1943. Initially, it was interpreted to be a remote population and a great range extension of Hinnites corallinus Sowerby I, 1827. This was due not only to the great similarity in shell morphology, but also largely because the type locality of H. corallinus was originally recorded as Eastern Africa, still in the Indo-West Pacific. Later, however, this was found to be an error and the correct type locality of H. corallinus was deemed to be southwestern Africa; making it very improbable for the Ogasawara shell to represent the same species. Upon careful re-examination of the morphological characters, it was found to have several key differences from H. corallinus, most importantly a 'shagreen' microsculpture on both ears (visible as small white triangles on the images) which H. corallinus completely lacks, as well as the much smaller size (up to 55mm vs up to 150mm). It was therefore described as a new species in 1993, using a complete specimen from the famous Ryosuke Kawamura collection as holotype. In fact, it is known today that although several species of Pectinidae around the world abruptly changes to semented lifestyle and therefore appear superficially very similar (once known as the 'Hinnites' group), they have evolved independently from various pectinid groups and the similarity is a result of convergent evolution. The 'shagreen' sculpture on the ears is also seen in many other Western Pacific pectinids that have an ordinary Chlamys-like shell, and is an important supporting evidence in placing it in Laevichlamys, its current genus. A very famous and rarely available species, it is much sought-after by collectors especially in Japan; its apparent rarity is mostly due to the fact that the Ogasawara Islands are very difficult to access and specimens are therefore rarely taken. Individuals vary greatly in growth patterns, many become semi-buried in coral while others remain on the surface and are easy to remove (as shown). A filter-feeding bivalve, it inhabits moderately shallow water around -10~40m. Typical shell length around 35mm, extremely large specimens may exceed 50mm.
Livonia mammilla (Sowerby I, 1844) <br /> VOLUTIDAE<br /> In shark nets, Banks Strait, Tasmania, Australia, 268.9mm <br /> <br /> With an unmistakable gigantic protoconch the "False Baler" is a large and iconic volutid endemic to Australia, ranging from Queensland to Southern Australia, including Tasmania. The specific epithet unsurprisingly refers to the exceptionally mamillate protoconch, which is not deciduous and remain attached to the teleoconch throughout the entire life. The holotype specimen is actually a juvenile and the protoconch therefore appeared even more dramatic than in an adult shell. The common name, on the other hand, is a reference to its superficial similarity with species of the genus Melo, the true baler shells. The shell is thin and lightweight, usually adorned with two wide bands of 'zigzag' patterns and has an orange aperture. It is however a rather variable species, especially with regards to the pattern, and completely unpatterned individuals are not uncommon. Specimens from Sandy Cape, Queensland, its northern limit, often show finer 'zigzac' patterns and have a much shorter spire resulting in a stouter overall form. Specimens with a white aperture and interior has been given the name leucostoma Mayblom, 1951, but the name carries no taxonomic validity as such specimens occur side-by-side with orange-mouthed ones and is merely a colour variation. A carnivorous and predatory gastropod, it inhabits sandy bottoms of moderately deep subtidal waters around -80~400m in depth. Although locally a moderately common species the shell is quite prone to encrusting damage and inclusions, making it very difficult to find a high quality specimen with a clean pattern. Typical shell length around 240mm, extremely large specimens are known to exceed even 310mm. Surprisingly perhaps, hybrids appear to exist between it and the much smaller sized congener Livonia roadnightae (McCoy, 1881). Such supposedly hybrid specimens carry characteristics of both species and was originally described as a new species Livonia quisqualis Iredale, 1957. These are extremely rare and only a few have been discovered so far.
Stirpulina ramosa (Dunker, 1882) <br /> CLAVAGELLIDAE<br /> -100m, Kominato, Kamogawa, Chiba Prefecture, Japan, 61.2mm <br /> <br /> A truly ecccentric and extraordinary bivalve, Stirpulina ramosa is a 'watering-pot' clavagellid that during development stops growing its bivalved shell and abruptly switches to growing a calcareous tube. Although an array of other superficially similar genera such as Brechites and Nipponoclava are known in the superfamily Clavagelloidea, recent researches have revealed that the bizarre life style of building an adventitious tube and living buried in the sand in fact evolved twice within the superfamily Clavagelloidea, once in Clavagellidae and once in Penicillidae. All other such genera belong to the Penicillidae radiation, and Stirpulina ramosa is the only extant member of the genus. This makes it the only surviving endobenthic tube-dwelling clavagellid in the world, a remnant species from Late Cretaceous and a "living fossil". All other living clavagellid species live a sessile life cemented to hard substrates and do not live buried in sand. A clear difference from the penicillids is that it only has the left valve cemented to the calcareous tube, whereas all tube-building penicillids have both valves cemented. The right valve remain free and mobile within the tube. Another difference is that the 'watering-pot' end of the tube consists of bifurcating tubules, a feature not seen in the 'watering-pot' of penicillids. An endemic species of Japan inhabiting sand and gravel bottoms -50~200m deep south of Chiba Prefecture, it is a filter-feeder and the tip of its tube is always protruded slightly from sand to access sea water. A very uncommon species, usually only shattered empty tubes are collected; live-collected specimens are extremely scarce. The only recorded specimen with soft parts preserved was housed in the collection of Emperor Shōwa Hirohito, and this was dissected by the eminent malacologist Prof. Brian Morton in order to reveal the anatomical differences with penicillids. Typical length of the adventitious tube around 70mm, extremely long tubes may exceed 100mm.
Cylindrus bengalensis (Okutani, 1968) <br /> CONIDAE<br /> -80~120m, Trawled, Off Racha Island, Phuket, Thailand, 2016/i, 113.4mm <br /> <br /> With a glorious textile-like tent pattern the "Bengal Cone" is an exceedingly famous conid ranging from Andaman Sea to Bay of Bengal, reaching southeastern India. Once exceedingly rare and most sought-after, today it has become much easier to obtain and is considered only uncommon. Large, perfect specimens are however still rarely seen and much treasured. A carnivorous and predatory gastropod feeding on polychaete worms, it inhabits sandy to muddy bottoms of moderate depths around -50~150m deep. Typical shell length around 100mm, extremely large specimens may exceed 140mm. Although it resembles the closely related congener "Glory-of-the-Sea" Cylindrus gloriamaris (Chemnitz, 1777) and was thought to be a local form of it when initially discovered, it can be distinguished relatively easily by its taller spire, narrower shoulder, and larger tent-like patterns. From this similarity, it is also known as the "Glory-of-Bengal". One of the most beautious species described by the eminent Japanese malacologist Prof. Takashi Okutani, it remains one of his favourite species of all time.
Alcithoe benthicola (Dell, 1963) <br /> VOLUTIDAE<br /> -500~600m, Dredged, Off north side of North Island, New Zealand, 2015/xii, 245.8mm <br /> <br /> Characterised by an exceptionally graceful tall spire Alcithoe benthicola is the largest of all extant species of Alcithoe, a volutid genus largely restricted to New Zealand. No exception to the majority, it is an endemic species of New Zealand and has a narrow distribution limited to the northern side of North Island, northward from Bay of Plenty. A carnivorous and predatory gastropod, it inhabits muddy substrates of deep water around -400~800m in depth. Dell gave it the name 'benthicola' in recognition of its very deep distribution. Typical shell length around 200mm, although the most extreme specimens are known to exceed 270mm. A well sought-after rarity among the New Zealand volutes partly due to its large size, it is very difficult to obtain a decent and large specimen over 240mm as shown. Although the ventral (i.e., aperture) side is usually clean, the dorsum side of adult individuals is always covered in dark deposits and circular marks. In fact these are not due to damage or contamination in shell formation, but instead is the attachment scar of its egg capsules. This intriguing behaviour is apparently unique to this species among all extant Alcithoe species. It seems that a dwarf population rarely exceeding 150mm apparently exists off Poor Knights Islands, further research may justify this population as a valid subspecies or even a distinct species.
Cantrainea panamensis (Dall, 1908) <br /> COLLONIIDAE<br /> -800m+, Trawled on muddy bottoms, Off Constitucion, Maule, Talca Province, Chile, 21.8mm <br /> <br /> Cantrainea panamensis is a large and handsomely sculptured colloniid characterised by a strongly angulate shoulder and numerous spiral cords of various strength. Rather widely distributed in the eastern Pacific ranging from Baja California to Chile, it is an omnivorous detritus layer grazer inhabiting soft bottoms of deep water around -400~1100m in depth. It is a cold-seep associated gastropod reported from the Concepción Methane Seep Area in Chile, although it also occurs in regular non-chemosynthetic seafloor. It is quite a rarity especially large specimens complete with the calcareous operculum, although in the methane seep site it is apparently locally quite common. It is quite variable in the number of weak spiral cords, but the general profile is little-varied. Typical shell length around 15mm, very large specimens may exceed 25mm.
Turriconus excelsus (Sowerby III, 1908) <br /> CONIDAE<br /> -120~150m, By tangle net, Panglao Island, Bohol, Philippines, 2004/iii, 84.0mm <br /> <br /> The "Illustrious Cone" is one of the most coveted rare cones of all, and surely one of the most attractive. It is characterised by a tall, stepped spire and is unmistakable among all known conids. A famous species included in S. Peter Dance's fifty "Rare Shells" (1969), only three specimens were known then and none of them fresh. It has a wide distribution range in the Indo-Pacific ranging from Burma to Philippines to Japan to northern Australia to Solomon Islands. The type locality is New Caledonia, which was for a long time considered to be a mistake but recently some dead shells have been collected there, confirming its occurence. Most specimens seen on the market today comes from Balut and Aliguay islands of Philippines. A predatory gastropod feeding on polychaete worms, it inhabits rather deep water of about -100~400m in depth. Average shell length around 75mm, gigantic specimens may exceed 110mm. 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.
Buccinum bombycinum Dall, 1907<br /> BUCCINIDAE<br /> -600~650m, From muddy bottoms by traps, Off Yaizu, Shizuoka Prefecture, Suruga Bay, Japan, 2016/iii/15, 47.0mm <br /> <br /> Buccinum bombycinum is a small cold-water whelk With an exceptionally glossy and smooth periostracum for the genus. Although the supposed documented distribution range is from Sakhalin, Russia to Suruga Bay, Japan, virtually all specimens have surfaced from Suruga Bay, especially off Yaizu. A rare species, it is much sought-after by collectors especially in Japan and it is very difficult to obtain a specimen from outside Japan. A carnivorous and scavenging gastropod, it inhabits muddy bottoms of deep water around -350~800m in depth. Most specimens are taken by bait-traps aimed at either whelks or crabs, although some have surfaced as by-catches of fisheries targeting hagfish and other deep-water fishes. Typical shell length around 40mm, extremely large specimens may exceed 50mm. Apparently it is one of the most delicious Buccinum species, despite its rarity and small size. Numerous spiral threads are present on the shell surface in two sections, the strength of these vary to some extent among individuals.
Perisserosa guttata (Gmelin, 1791) <br /> CYPRAEIDAE<br /> -100~200m, By tangle nets, Tinina, Balut Island, Mindanao, Philippines, 2015/xii, 64.5mm <br /> <br /> The "Great Spotted Cowrie" is a lovely classic rarity among cypraeids characterised by circular bright spots on the dorsum and long tooth on the base extending to the dorsum as marginal lines. One of S. Peter Dance's fifty "Rare Shells" (1969), only sixteen were known by 1963 according to a list of known specimens published then by Woodward and it was exceedingly rare until the late 1900s. Today it is known to be a widely distributed species ranging from Maldives to Japan to Philippines to Queensland, Australia; it is very variable and several forms / subspecies names are currently being used. The nomimal subspecies occurs from Philippines to Queensland and is uncommon, best known from moderate depths around -25~100m in the Philippines where specimens with clear large spots are taken by diving or tangle netting. The form azumai (Schilder, 1960) is a northern form of guttata with smaller indistinct spotting and often lacking the labral blotch known from Japan and East China Sea; in recent years the Chinese trawlers are producing a huge quantity of this form from the East China Sea making it very common and inexpensive, but most specimens are quite poor. The form bicallosa (Raybaudi, 1985) refers to an angular form with well-developed white callous on both sides best known from Philippines. It is extremely rare in Queensland, its southern limit, and the specimens from here (usually deeper water around -150~300m) may represent a real subspecies; although not formally named these are often referred to as "queenslandica" on the market. The only widely accepted subspecies except the nominal guttata guttata is the uncommon Indian Ocean subspecies guttata surinensis (Raybaudi, 1978) from deeper waters (-100~300m) of Maldives to Thailand; characterised by an depressed oval shape, fine spots, darker alnd larger basal blotches, and much longer marginal lines. It is an omnivorous gastropod often inhabiting crevices of rocky walls, emerging at night to feed on a mixture of sessile invertebrates (such as bryozoans and sponges) and algae. Extremely variable in size, the typical shell length is around 55mm but specimens smaller than 35mm and larger than 85mm are known to exist; specimens less than 45mm or over 70mm are rather rare. It is still one of the most sought-after cowries today, giant dark specimens with large well-defined spots are perhaps the most coveted although an ideal specimen is still very difficult to obtain.
Tenagodus ponderosus Mörch, 1861 <br /> SILIQUARIIDAE<br /> -15m, Dived inside sponge, Albany, Western Australia, Australia, 2003/xii, 94.5mm <br /> <br /> The "Ponderous Worm Snail" is a bizarrely coiled siliquariid with regularly coiled early whorls abruptly changing to an uncoiled tube. An obligatory sponge commensal, it spends the entirely life within the body of the host sponge which provides shelter and protection. It is a filter-feeder and feeds by drawing water in through the aperture, filtering food particles using the ctenidium (gill), and finally discharging the filtered water through the slit. The reason for the uncoiled growth is to catch-up with the host's growth, as to effectively filter-feed its aperture needs to be situated at the surface of the sponge. The coiling characteristics therefore varies among individuals, largely influenced by the host's growth patterns. Usually a number of specimens are found together inside a single host sponge. There is a corneous operculum heavily sculptured with opercular bristles, an important taxonomic character in Siliquariidae where the shell characteristics are in many cases too variable to be useful below genus level. It inhabits shallow subtidal waters down to about -50m and ranges from the Arafura Sea to western and northeast Australia, though the actual distribution may be slightly wider. It is very similar in general appearance to the Atlantic species T. senegalensis (Sowerby II, 1876) as well as the Mediterranean species T. obtusus (Schumacher, 1817), but is usually readily distinguishable by the slit morphology -- the slit of T. ponderosus is a series of elliptical holes on the coiled whorls then gradually becoming denticulated and then finally smooth-sided at the uncoiled part, whereas that of T. senegalensis and T. obtusus is smooth-sided without denticulation throughout the entire teleoconch. Its shell is also slightly thinner and generally contain less significant cracks compared to T. senegalensis and T. obtusus. Many authors actually consider T. senegalensis and T. obtusus to be synonymous, although this is still a topic of debate. Typical shell length around 100mm, extremely large specimens may exceed 200mm. Although a common species, it is rather difficult to find a well-sized specimen in good condition on the shell trade market. For many years it was placed in the genus Siliquaria, until Bieler rendered it as an objective synonym of Tenagodus in 1992.
Homalopoma eoa Azuma, 1972 <br /> COLLONIIDAE<br /> -400m, Trawled, Punta Engano, Lapu-Lapu City, Mactan Island, Philippines, 2016/iii/31, 12.3mm <br /> <br /> Vivid and brilliant like a jewel the "Dawn Turban" is one of the most prestigous rarity among turban shells and their allies. First discovered from South China Sea and once thought to be endemic to Taiwan, it was subsequently also found off Izu Islands, Japan and later in the Philippines. A large Homalopoma with a beautiful wholly bright red shell characterised by numerous axial ribbing, it was made famous by T.C. Lan who included it in his monumental work "Rare Shells of Taiwan" (1979). Most specimens of the early days have surfaced as by-catches of Taiwanese coral fisheries, though this supply has effectively stopped. Today it remains extremely scarce across its range, especially live-taken specimens. Most likely an omnivorous detritus layer grazer, it occurs in deep water around -200~500m. It is little-varied in conchological characters except that the axial ribbing may vary in strength and frequency. Typical shell length around 12mm, very large specimens may exceed 15mm. The specific epithet 'eoa' is apparently derived from Eos, the rosy-armed goddess of the dawn in Greek mythology; as its radiant hue is reminiscent of the colour of daybreak. Homalopoma striatum Suzuki, 1972 is a synonym, the name being inspired by the axial ribs.
Ginebis japonica (Dall, 1925) <br /> CALLIOTROPIDAE<br /> -180~200m, Uraga Channel, "Uchibo", Chiba Prefecture, Japan, 2016/iv/04, 27.6mm　<br /> <br /> With a brilliant silvery hue Ginebis japonica is a rather rare calliotropid endemic to Japan, with a distribution range from Sagami Bay to Tosa Bay. A detritivorous gastropod that feeds by swallowing sediment and digesting the organic matter within, it inhabits sandy to muddy bottoms of rather deep water around -150~800m. Very similar to and often confused with its much more common sister species Ginebis crumpii (Pilsbry, 1893), but differs from it by having three rows of strong tubercles instead of two. Furthermore, in G. japonica the tubercles are more numerous, and in mature specimens the outer lip is more flared. Typical shell length around 30mm, extremely large specimens may exceed 40mm. The genus name Ginebis is taken directly from Japanese and literally means "silvery top shell".
Niso splendidula (Sowerby I, 1834) <br /> EULIMIDAE<br /> -35~70m, Dredged, Gulf of Chiriquí, Panama, 23.1mm <br /> <br /> The superbly patterned "Splendid Niso" is a truly amazing member of Eulimidae, which are commonly much smaller in size and lack significant pattern. Due to its beauty it is one of few eulimid species highly coveted by shell collectors. An uncommon species, it ranges from Gulf of California to Ecuador and inhabits sandy bottoms of moderate depths around -20~80m deep. Members of Eulimidae exclusively parasitise various echinoderms and live on the host's body fluid. The genus Niso is known to parasitise starfish (Asteroidea) and although the host species of Niso splendidula is not known, it is not considered to be an exception from this mode of feeding. Like other species of Niso, it is most likely hemiparasitic and spends most of its time free-living and only attach to the host when feeding. A ptenoglossate radula is present, unlike many other eulimids. Typical shell length around 25mm, extremely large specimens sometimes exceed even 40mm.
Scutellastra mexicana (Broderip & Sowerby I, 1829)<br /> PATELLIDAE<br /> Low tide, On large boulder, Barra de Navidad, Jalisco, Mexico, 205.5mm <br /> <br /> With large individuals often exceeding 200mm in shell length the massive "Giant Mexican Limpet" is the largest of all living limpets. Ranging from western Mexico to Peru, it is the only Scutellastra species found in the eastern Pacific. An algae-grazing herbivorous gastropod living attached on hard substrates, it occurs from low tide to shallow subtidal waters down to about -10m. Although it used to be a common species widely used as a local delicacy in dishes such as ceviche, overharvesting led to a great population decline and was apparentl close to extinction across parts of its range in Mexico. Today it is uncommon to rare at the typical shell length around 150mm or less, large specimens exceeding 200mm are very rarely found. It is said that the largest examples may attain a colossal 350mm. The shell is characteristically rostrated and oval-shaped, it is also exceptionally thick and can easily withstand an adult human being standing on it. Although large specimens appear featureless due to erosion and encrustation, it carries numerous major and minor dorsal radial ribs which is much more clearly seen in young individuals.
Neptunea contraria (Linnaeus, 1771) <br /> BUCCINIDAE<br /> -150~250m, Trawled, Off northwest coast of Portugal, 2004/x, 89.3mm <br /> <br /> The "Left-Handed Neptune" is a peculiar buccinid that is normally sinistral or coiled left-handed, hence the name. An eastern Atlantic to Mediterranean species, it ranges from Spain to Portugal to Morocco. It inhabits a rather wide bathymetric range of around -100~800m deep and is known to live deeper in the southern part of its range. It is a common carnivorous gastropod throughout its range. Although generally little-varied and cannot be mistaken with any other species, it is greatly variable in size. Typical shell length is around 100mm, but very large individuals may attain 190mm. The colouration is also variable and ranges from white to dark brown. Two well-known synonyms include perversus Kiener, 1840 and sinistrorsus Deshayes, 1832, both also refer to the reverse-coiling characteristic in this species.
Adelomelon beckii (Broderip, 1836) <br /> VOLUTIDAE<br /> -50~80m, Trawled, Off Mar de Plata, Buenos Aires Province, Argentina, 400.2mm <br /> <br /> A colossal volutid, the "Beck's Volute" ranges from Espiritu Santo, Brazil to Tierra del Fuego, Argentina and is the largest volute of South America, Due to its large size, it is recently growing in importance as seafood locally and the shell is a popular decorative item. A carnivorous and predatory gastropod feeding chiefly on other gastropods and bivalves, it inhabits soft bottoms of moderate depths around -20~80m and is locally common. Typical shell size around 300mm, extremely large specimens may exceed even 490mm. Specimens are very prone to damage from encrusting polychaete tubes and barnacles, large specimens with clean surface are very difficult to obtain. The large protoconch is characterised by a sharp protrusion posteriorily. It often carries irregular 'lightning' patterns of ziczac lines, but the occurence of these is highly variable and many specimens lack any significant patterning. The outer lip flares slightly in geronic specimens.
Margarites rossicus (Dall, 1919) <br /> MARGARITIDAE<br /> -100~150m, Trawled, Sea of Okhotsk, Russia, 1990/vii, 28.4mm <br /> <br /> The "Pearly Margarite" is a brilliantly iridescent margaritid occuring from Hokkaido, Japan to Sakhalin, Russia in the Sea of Okhotsk. The surface layer of its shell is dull grey, but this layer is usually heavily corroded to reveal the pearly nacreous layer beneath (as shown). A generalist gastropod feeding by grazing and swallowing detritus, it inhabits a rather wide bathymetric range around -100~550m deep. An uncommon to rare species it is only very occasionally offered in the shell trade market, although it is evidently not uncommon in its natural habitat. Typical shell length around 25mm, extremely large examples may reach 35mm. It was once treated by many as a calliostomatid in the genus Otukaia due to the superficial similarity in the shell, but currently the initial assignment by Dall in Margarites is deemed correct.
Pteropurpura falcata (Sowerby II, 1834) f. adunca (Sowerby II, 1834) <br /> MURICIDAE<br /> -50m, Off Hota, "Uchibo", Chiba Prefecture, Japan, 2016/iii/18, 55.0mm<br /> <br /> The spectacularly winged "Adunca Murex" ranges from Hokkaido, Japan to Korea to Taiwan. It is a very variable species with regards to the number of varices per whorl, development of varices, and the significance of spiral cords. The number of varices, especially, may vary from three to six per whorl. This led to a few synonyms being generated for the various forms. The name P. falcata was once reserved for those specimens with few varices per whorl, with well-developed wings, and lacking strong spiral ribs. The most famous synonym is undoubtedly P. adunca (Sowerby II, 1834), originally applied to specimens with more numerous varices and conspicuous spiral cords. For a very long time P. adunca was treated as a separate species in its own right until Houart & Sirenko synonymised it with P. falcata in 2003. Currently it is often used as a form name (like here), some still retain the opinion that the two are separate species. A carnivorous gastropod feeding mostly on bivalves, it inhabits hard substrates of moderate depths around -20~80m. Typical shell length around 45mm, very large specimens exceeds 70mm. Although not uncommon, it is rare to find large specimens with wide varices in good condition.
Pteropurpura falcata (Sowerby II, 1834) f. adunca (Sowerby II, 1834) <br /> MURICIDAE<br /> -50m, Off Hota, "Uchibo", Chiba Prefecture, Japan, 2016/iii/18, 56.0mm / 55.0mm <br /> <br /> The spectacularly winged "Adunca Murex" ranges from Hokkaido, Japan to Korea to Taiwan. It is a very variable species with regards to the number of varices per whorl, development of varices, and the significance of spiral cords. The number of varices, especially, may vary from three to six per whorl. This led to a few synonyms being generated for the various forms. The name P. falcata was once reserved for those specimens with few varices per whorl, with well-developed wings, and lacking strong spiral ribs. The most famous synonym is undoubtedly P. adunca (Sowerby II, 1834), originally applied to specimens with more numerous varices and conspicuous spiral cords. For a very long time P. adunca was treated as a separate species in its own right until Houart & Sirenko synonymised it with P. falcata in 2003. Currently it is often used as a form name (like here), some still retain the opinion that the two are separate species. A carnivorous gastropod feeding mostly on bivalves, it inhabits hard substrates of moderate depths around -20~80m. Typical shell length around 45mm, very large specimens exceeds 70mm. Although not uncommon, it is rare to find large specimens with wide varices in good condition.
Livonia nodiplicata (Cox, 1910) <br /> VOLUTIDAE<br /> -50~100m, Trawled on sand and gravel bottom, Off Augusta, Western Australia, Great Australian Bight, Australia, 345.5mm <br /> <br /> The magnificent "Cotton's Volute" is an extremely large volutid endemic to southern and western Australia. It is characterised by and well-known for its deciduous bulbous protoconch, which naturally breaks off after the animal reaches a certain size. This differs from all other recent Livonia species, leading Iredale to propose a new genus Cottonia for it in 1934; although this is now generally understood to be unnecessary and is treated as a synonym of Livonia. To be exact, Iredale established Cottonia for a famous junior synonym of it -- Scaphella dannevigi Verco, 1912. Sometimes a part of the protoconch remains (as shown) to adulthood, and extremely rarely adult specimens with complete protoconch are found. A carnivorous gastropod, it inhabits sand and gravel bottoms across a rather wide bathymetric range from subtidal waters as shallow as -5m to a depth of -200m. Many large specimens are dived or fished in relatively shallow water below -50m deep. Although not uncommon locally, large and perfect specimens are costly to obtain on the shell trade market. Typical shell length around 320mm, extremely large specimens may exceed 390mm.
Calyptogena (Akebiconcha) kawamurai (Kuroda, 1943) <br /> VESICOMYIDAE<br /> -300~350m, Trawled on mud by fisherman, Off Choshi, Kashima-Nada, Chiba Prefecture, Japan, 2009/iii/20, 150.1mm <br /> <br /> Calyptogena kawamurai is a large vesicomyid clam endemic to Japan. Originally described from a single specimen taken by longline from -180m in Sagami Bay, it was later found as far north as Kashima-Nada. In 1992, another Calyptogena species was described from the shallowest hydrothermal vent known in the Okinawa Trough, Minami-Ensei Knoll, as C. solidissima Okutani, Hashimoto & Fujikura, 1992. Although this was very similar to C. kawamurai, the authors found very fine and regular radial threads on both valves and used that as the main diagnostic character. As deep-sea research progressed in Japan, Calyptogena specimens identified as C. solidissima was found in a number of methane seeps in Suruga Bay and Okinawa, but these specimens did not have any radial threads and were therefore not significantly different from C. kawamurai. These observations led to a study in 2006 by Prof. Shigeaki Kojima and colleagues who used molecular phylogeny and population genetics to study populations of C. kawamurai and C. solidissima, discovering that the two were genetically indistinguishable and shell characteristics overlap. In fact, some specimens from Minami-Ensei Knoll also lacked fine radial threads. Following these results, the authors concluded that C. solidissima should be treated as a junior synonym of C. kawamurai. Calyptogena kawamurai, therefore, has a distribution range from Kashima-Nada to Okinawa within Japan, and is notable for being able to inhabit both methane seeps and hydrothermal vents (probably also reducing sediments for the shallower populations). The shallowest Calyptogena species in Japan it may be found as shallow as -100m, although vast majority are found at a depth from between -300~900m. A chemosymbiotic bivalve, it has a much enlarged gill housing chemosymthetic endosymbionts and relies on these for nutrition. Unlike other Calyptogena species, its comparatively shallow habitat means it is sometimes caught as a by-catch in trawl fisheries, especially spider-crab fisheries, and such specimens are often offered to collectors. As it requires patchily distributed reducing environments such fortunate catches remain very scarce, and it remains a highly desirable shell of great rarity especially for Japanese collectors. Typical shell length around 110mm, extremely large specimen such as the one shown may exceed 150mm. The monotypic genus Akebiconcha was erected for it in the original description; although often treated as a subgenus some authors consider it to be still worthy of a full genus. The name Akebiconcha draws attention to the similarity between its shell and the fruit of the plant genus Akebia, a traditional fruit in Japan which is simply called "Akebi" in Japanese. Accordingly, in Japan it is known as the "Akebi Shell".
Gaza olivacea Quinn, 1991 <br /> MARGARITIDAE<br /> ±500m, Trawled, Off Guajira Peninsula, Colombia, 2010, 43.5mm <br /> <br /> Gaza olivacea is a superbly iridescent Atlantic margaritid ranging from the Caribbean Sea to Rio de Janeiro, Brazil. A very large and attractive Gaza, it is a classic rarity and highly coveted by collectors but its avaiability is very scarce in good condition. A deep-water species, it inhabits sandy to muddy bottoms around -300~700m in depth. The diet or mode of feeding is not well-known for the genus Gaza in general, although sand and mud have been found in the digestive tract which suggest they swallow detritus and digest the organic matter within. Typical shell length around 35mm, extremely large specimens may exceed 45mm. The apex is deciduous and is always missing in adult specimens. It is sometimes confused with the conchologically similar Gaza superba (Dall, 1881) which reaches a similar size, but can be easily distinguished by its taller spire and the umbilicus being nearly completely covered by callus (only half covered in G. superba).
I don't usually post fossil molluscs but am more than happy to make an exception for Ecphora! <br /> <br /> Ecphora quadricostata (Say, 1824)<br /> MURICIDAE<br /> Pliocene Epoch, Neogene; Lower Yorktown Formation, Beaufort County, North Carolina, U.S.A. (4.5 to 4.3 million years ago), 2000/vi, 50.0mm <br /> <br /> With truly astonishing sculpture the "Four-ridged Ecphora" is an extinct muricid and is certainly one of the most phenomenal fossil Cenozoic gastropods. As the name suggests it is characterised by four very strong spiral ribs on the body whorl, which are closer spaced in smaller specimens. Due to its beauty it is a much sought-after species by both fossil and shell collectors alike, and is a popular target for fossil hunting in the formations where it is found. Fragments are common, intact specimens are quite uncommon. Presumably it was a carnivorous and predatory gastropod inhabiting shallow waters and mainly feeding on bivalves. Typical shell length around 60mm, extremely large specimens may exceed 110mm. Rather unfortunately, this remarkable species had a convoluted taxonomic history due to much confusions in localities of its type material. When Thomas Say described this species (as "Fusus 4-costatus", interestingly) he listed the type locality as Miocene, Maryland; but it was later discovered that most of his materials actually originated from Pliocene Yorktown Formation, Virginia. More confusingly however, a specimen matching the original drawing could not be found from Say's existing Virginia materials and evidences suggested the specimen actually came from Pliocene, South Carolina. Unable to find the holotype, a lectotype from Pliocene, Yorktown, Virginia has been selected. Eitherway, E. quadricostata is now restricted to the Pliocene strata ranging from Virginia to Florida, U.S.A. This caused a problem because this meant Ecphora specimens truly from Miocene, Maryland was still without a name, but it is Maryland's Official State Fossil (as E. quadricostata, of course). Finally, the Miocene species from Maryland was named E. gardnerae in 1987 by Druid Wilson and following that the name of Maryland's State Fossil was also corrected in 1994. Ecphora gardnerae was once thought to be the earliest illustrated American fossil in the published literature (by Martin Lister in 1770), but this honour actually goes to Chesapecten jeffersonius (Say, 1824) which was illustrated in 1687, strange enough also by Lister. The entire genus Ecphora has gone extinct by the Late Pliocene.
Acreuciroa rostrata (Jaeckel & Thiele, 1931) <br /> EUCIROIDAE <br /> -300~500m, Trawled, Off Taishou-jima (i.e., Sekibi-sho), Senkaku Islands, 2016, 56.1mm <br /> <br /> The "Rostrate Euciroa" is a large Western Pacific euciroid ranging from the souhern half of Japan to around Indonesia. Its shell has a very thick nacreous inner layer concealed only by a rather thin external layer, often worn off near the apex (as shown) revealing the stunningly beautiful prismatic iridescence below. Used to be quite a rarity but in the recent years specimens have become much more readily available from Chinese trawlers working in the East China Sea, rendering it to no more than uncommon. A carnivorous and predatory bivalve inhabiting sandy to muddy bottoms of quite deep water around -200~600m, it predominantly feeds on small arthropods and polychaete worms. Typical shell length around 45mm, extremely large specimens may exceed 60mm. It is the type species and currently the sole species in the genus Acreuciroa.
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