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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.

Paramoria guntheri (Smith, 1886) <br /> VOLUTIDAE<br /> -21m (-70 ft), In sandy rubble, By diver, Thorny Passage, South Australia, Australia, 54.5mm <br /> <br /> The deliciously patterned "Gunther's Volute" is a celebrated classic rarity among the volutes, endemic to southern Australia. Initially only known from a handful of dead-collected specimens, a live specimen was first discovered in May 1973 off Port Lincoln, South Australia. Photographs of this specimen was published, revealing to the world the equally beautiful animal, covered in a web-like pattern of similar colouration as the shell. A carnivorous and predatory gastropod, it inhabits sandy to muddy bottoms of shallow to moderate depths around -10~50m. Today it is still considerably rare and highly sought-after by collectors. The attractive pattern is rather variable and the axial lines vary considerably in frequency among specimens. The two spiral bands may be solid or dotted when present, but they may also be completely absent. The form without spiral bands is rarer and was originally described as a separate species Voluta adcocki Tate, 1889; now considered a synonym but is still widely used as a form name in shell trade. Furthermore, the shoulder nodes are also rather variable in strength. Typical shell length around 45mm, extremely large specimens may exceed 65mm.
Netastoma darwinii (Sowerby II, 1849) <br /> PHOLADIDAE<br /> Inside sand rocks, San Jorge Gulf, Caleta Olvia, Santa Cruz, Argentina, 2004/i, Coll. Andres R. Bonard, 39.2mm <br /> <br /> The "Darwin's Piddock" is a spectacular South American pholadid with a very peculiar shape, ranging from southern Brazil to Argentina. A rock-burrowing bivalve, it repeatedly rotates its shells using a set of specially adapted muscles to mechanically grind a tubular burrow in soft rocks, which it then reside within for the rest of its life. It is a filter-feeder inhabiting very shallow to shallow waters down to about 15m deep, during feeding it extends its siphons out of the burrow but rest of the body remains protected by the rock. A rather rare species, perhaps owing to the fact that it is difficult to locate, and even more difficult to extract intact from its rocky burrow. Typical shell length around 30mm, very large specimens may exceed 40mm. The genus Nettastomella was erected by Carpenter in 1865 to house this eccentric species, but it is now deemed to be an unnecessary replacement name for genus Netastoma, its current genus.
Gigantopelta aegis Chen, Linse, Roterman, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2785m, 'Tiamat Chimney', 37°47.03'′S, 49°38.97'E, Longqi hydrothermal vent field, Southwest Indian Ridge, ROV Kiel 6000 Dive 142 on-board RRS James Cook expedition JC67, 2011/xi/29, 40.2mm <br /> <br /> The "Aegis Shield" is a large hydrothermal vent endemic peltospirid known only from the Longqi (aka Dragon) hydrothermal vent field, Southwest Indian Ridge, Indian Ocean; which is a bathyal site around -2700~2800m in depth. It houses chemosynthetic endosymbiont bacteria in a much enlarged oesophageal gland, and appear to rely on these for nutrition. Interestingly both its shell and operculum are covered in a thick layer of iron oxide (i.e., rust), on the operculum especially this layer is a circular slab that can reach a thickness of 5mm. It is thus another "iron-armoured snail" like the 'scaly-foot gastropod' Chrysomallon squamiferum Chen et al., 2015. Most intriguingly however the 'scaly-foot', which it lives side-by-side with, has iron sulfide coating instead of iron oxide; it is not known why the two large peltospirids living in the same environment use different iron compunds to coat their exterior surface. Furthermore, its congener G. chessoia Chen et al., 2015 from Antarctic vents does not have such iron coating at all. The function (if any) of this coating is yet unclear, although microbial activity likely contribute to its formation. The specific epithet "aegis" refers to the renowned powerful mythical shield of Athena and Zeus from the Greek mythology; named for its great thickness and also the well-polished appearance which fits well with the description of the legendary shield which is sometimes described as "mirror-like". The bluish-white shell is quite thin, covered by a rather thick periostracum which is in turn covered by the thick rust layer. With an average shell length of 35mm and very large specimens reaching 44mm, it is a gigantic peltospirid only exceeded in size by C. squamiferum and G. chessoia. Although a common species in its habitat, due to the extreme difficulty in collecting specimens from hydrothermal vents, it is unfortunately a virtually unobtainable species for personal collection.
Gigantopelta chessoia Chen, Linse, Roterman, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2646m, ‘Cindy's Castle’ hydrothermal vent site, 56°05.31′S, 30°19.10′W, E2 segment, East Scotia Ridge, By ROV Isis Dive 189 on-board RSS James Cook cruise JC80, 2012/xii/12, 45.9mm <br /> <br /> The "ChEsSO's Shield" is a large hydrothermal vent endemic peltospirid known only from the Antarctic deep-sea hydrothermal vents in E2 and E9 segments of the East Scotia Ridge, off South Sandwich Islands. The vent sites it inhabits are bathyal, around -2400~2600m in depth range. It houses chemosynthetic endosymbiont bacteria in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With an average shell length of around 35mm and very large specimens exceeding 45mm, it is not only the largest peltospirid but also the largest member of the clade Neomphalina. Its size record is closely followed by the 'scaly-foot gastropod' Chrysomallon squamiferum Chen et al., 2015 (reaching 45.0mm) and its congener Gigantopelta aegis Chen et al., 2015 (reaching 44.2mm). The shell is rather thin but rigid, and covered by a thick olive to brown periostracum of a similar thickness. The operculum is unusually large for the family, most of which have reduced operculum or completely lost it, and covers the entire aperture. The genus name "Gigantopelta" is taken from "Giganto-", which means "giant" but is also an reference to the legendary Giants of the Greek mythology; and "pelta" meaning "shield", referring to the large operculum as well as the family name Peltospiridae. The specific epithet "chessoia" is taken from the ChEsSO (Chemosynthetic Ecosystems of the Southern Ocean) project, primarily funded by the Natural Environment Research Council, United Kingdom, which in 2010 first discovered and surveyed the Antarctic vents it inhabits. ChEsSO was part of the ChEss (Biogeography of Deep-Water Chemosynthetic Ecosystems) project in the Census of Marine Life initiative. Although a dominant species in its habitat, due to the extreme difficulty in collecting specimens from hydrothermal vents it is unfortunately a virtually unobtainable species for personal collection.
Samarangia quadrangularis (Adams & Reeve, 1850) <br /> VENERIDAE<br /> Dived, Zanpa-Misaki, Yomitan, Okinawa Island, Okinawa Prefecture, Japan, 2006/vi, 59.3mm <br /> <br /> The "Samarangia Clam" is a highly unusual venus clam with a peculiar habit of cementing sand grains over its shells to form 'pseudo-shells' that completely conceal the true shells, termed aranaceous coating. The sand grains are first held together by a mucus layer, and later become permanently concreted by aragonitic calcium carbonate. The function of this rather thick coating has been argued to be protective and camouflage, although no direct evidence has been presented. Surface of the arenaceous coating is ornamented with a number of prominent radial ribs, the strongest few being clearly nodulous. The underlying true shell is actually completely smooth and overlaid by a thin periostracum, the only way to see it is by removing the coating through intensive polishing. Its distribution range is quite wide in the Western Pacific from the Coral Sea to Honshu, Japan to Indonesia. Previously its range was thought to extend as far as Mauritius and Reunion, but recent studies have separated the Indian Ocean and Red Sea population as a distinct species -- Samarangia lewinsohni Mienis, 2011. A filter-feeding bivalve inhabiting sandy bottoms of rather shallow waters around -10~50m, it is not uncommon throughout its range. Typical shell length around 70mm, very large specimens may exceed 100mm.
Neancistrolepis glabra Habe & Ito, 1973 <br /> BUCCINIDAE<br /> -730~740m, 44°12'E 144°29'E, Trawled, Off Abashiri, Hokkaido, Japan, 2006/vii, 57.2mm <br /> <br /> Neancistrolepis glabra is a cold-water whelk with smooth, glossy periostracum ranging from Hokkaido, Japan to the Okhotsk Sea. A carnivorous and often scavenging gastropod, it inhabits sandy to muddy bottoms of quite deep water around -600~800m. It is a very rarely seen species on the international shell trade, even locally in Japan it is considered a rare species. In fully adult specimens, the outer lip thickens slightly and characteristically flares out, extending anteriorly. The periostracum is darker coloured in adults than juveniles and peels off rather easily when dried. The operculum is teardrop shaped and as usual for the genus Neancistrolepis it is much smaller than the aperture, though not as small as in the genus Parancistrolepis. Typical shell length around 100mm, very large specimens may exceed 140mm.
Spondylus crassisquama Lamarck, 1819<br /> SPONDYLIDAE<br /> -35~40m, Panama Bay, Panama, 2005/viii, 143.8mm <br /> <br /> Much better known by the name Spondylus princeps Broderip, 1833 which was recently synonymised with the current name, the showy "Pacific Thorny Oyster" gains its vernacular name from its distribution range in the Pacific Americas, from Baja California to Peru. Being rather variable in spine development and colouration it has a couple further synonyms including S. basilicus Reeve, 1856 which refers to an orange form, and S. dubius Broderip, 1833. Spondylus leucacanthus Broderip, 1833 with more sparce spines which are usually white was traditionally considered to be a form of this species but currently separated out as a valid species on its own right. A filter-feeding sessile bivalve like all spondylids, it lives attached to hard substrates around moderate depths of -10~50m. Typical shell length including spines around 100mm, very large specimens are known to exceed 170mm. Although a locally common species, specimens of fine quality are uncommon on the international shell trade market.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2785m, Longqi vent field, 37°47.03'S 49°38.97'E, Southwest Indian Ridge, Indian Ocean, 43.1mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2607m, Solitaire vent field, 19°33.41'S 65°50.89'E, Central Indian Ridge, Indian Ocean, Mauritius, 35.2mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2422m, Kairei vent field, 25°19.218S, 70°02.424E, Central Indian Ridge, Indian Ocean, 39.1mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Cymbiola perplicata (Hedley, 1902) <br /> VOLUTIDAE<br /> -30m, Dived on reef, Lihou Reef, Coral Sea, Australia, 60.0mm <br /> <br /> The "Entangled Volute" is a delightful volute characterised by stunning golden axial lines, and is a much sought-after rarity among the volutes. The original description was based on three poor beached shells from Australian fishermen, but with no further specimens being found its true provenance remained a mystery. That is, until its re-discovery in the late 1970s by Mr. Tom Nielson of Yeppoon, Queensland, Australia and his team. Nielson had already re-discovered other rare shells, including another rare volute Cymbiola thatcheri (McCoy, 1868), using special shell dredges in the early 1970s on-board the chartered boat "Coralita". His early searches for C. perplicata funded by Mr. John du Pont had ended in no avail, however; and it was only after repeated cruises (also on-board the "Coralita") that he finally managed to locate and collect live specimens of C. perplicata in the Coral Sea. His early expeditions were supposedly recorded in a film entitled "In Search of the Perplicata", though virtually no remaining copies of it appear to exist. Today it is known to be an endemic of the Australian Coral Sea, and remains rather scarce still. A carnivorous gastropod like all volutes, it inhabits sandy bottoms of shallow to moderate depths around -2~40m. Typical shell length around 65mm, extremely large specimens may reach 85mm.
Cyrtopleura costata (Linnaeus, 1758) <br /> PHOLADIDAE<br /> Dug out from intertidal mud, Low tide, Cedar Key, Florida, USA, Collected by Edward Nieburger, 1976/v/1, 172.4mm <br /> <br /> This delicate bivalve of otherworldly beauty is aptly named the "Angel Wing", and has attracted the adoration and fascination of shell collectors for hundreds of years. Each thin and almost translucent wing-like valves carry 24-27 strong radial ribs which carry numerous beads that convincingly look like feathers on the wing. It has a rather wide distribution range from Massachusetts, USA to as far south as Brazil, although vast majority of specimens on the market originate from Florida, USA. A large filter-feeding pholadid inhabiting muddy bottoms of very shallow water down to about -5m in depth, it is most common in intertidal waters just below the low-water mark and usually burrow deep into the mud, up to about a metre. The animal is bulky with a powerful foot as well as a hefty fused siphon which is so large that the two valves cannot be closed and instead permanently gape apart when alive. Each valve carry on the inside a apophysis, spoon-like appendage which is a point of attachment for the foot musculature. As usual for the genus Cyrtopleura it has a small butterfly-like mesoplax and also a large, entirely corneous protoplax (both shown) but lacks a metaplax. These accessory plates help cover part of the animal which would be exposed otherwise, due to the large gape in its valves, and is a common feature for members of the famly Pholadidae. When alive both valves are covered by a thin, brown periostracum which is often worn near the umbo. Although it is a common species, large specimens with both the mesoplax and especially the protoplax preserved are very difficult to acquire. Separated single valves are commonly washed ashore on beaches and is a beachcomber's favourite. Typical shell length around 130mm, extremely large specimens may reach 200mm. Its meat is edible and in Mexico, Cuba, and Puerto Rico it is harvested commercially for food and supports important fisheries. Aquacultural research has shown that it is a fast growing species and reaches 50-70mm shell lenth within six months of settlement.
Textilia adamsonii (Broderip, 1836) <br /> CONIDAE<br /> -20~30m, Dived, Rurutu Island, Austral Islands, French Polynesia, 1998/i, 41.0mm <br /> <br /> With truly spellbinding patterns the "Rhododendron Cone" is a great classic rarity among the conids and one of the most sought-after by collectors. One of S. Peter Dance's 50 "Rare Shells" (1969), it is still a very difficult shell to obtain today in fine condition. Although it is often beached after typhoons pass, but such specimens are typicall worn with badly damaged lip. A predatory gastropod like all conids, it is a piscivorous species which hunt fishes using venom injected from its harpoon-like radula. It inhabits sandy bottoms of coral reefs and lagoons and may be found from low intertidal waters down to moderate depths around -60m deep. The shell characteristically carry three broad spiral bands with sparse nebulous patterns which alternate with another three narrower spiral bands with small triangular spots. It has a rather wide distribution range in the Pacific Ocean ranging from Coral Sea to French Polynesia, and varies slightly in form, size, as well as pattern depending on the locality. Specimens from the Marquesas Islands, for example, are rather large and instantly recognisable by their exceptionally intense colouration and more cylindrical (rather than conical) form. Its vernacular name comes from a famous synonym, Conus rhododendron Jay, 1839, which is very appropriate but unfortunately must give way to Broderip's earlier name. Typical shell length around 35~40mm depending on the locality, extremely large specimens are known to exceed 55mm.
Angaria sphaerula (Kiener, 1838) <br /> ANGARIIDAE<br /> Panglao Island, Bohol, Philippines, 2010/x, 70.3mm <br /> <br /> With its astonishing ornamentation the "Kiener's Delphinula" is perhaps the most beautiful angariid, and one of the most exquisite of all gastropods. For a long time since its description it remained a very rare shell, even well into the 20th Century; S. Peter Dance chose it as one of his 50 "Rare Shells" (1969), describing it as "undoubtedly scarce and undeniably beautiful" (p.51). Today, however, it has been revealed to be a rather common species native to the tropical Western Pacific, best known from the Philippines where most specimens originate. An extremely variable species in spine formation, its spines can vary greatly in length, recurvedness, and in structure from a simple tube to being extensively webbed. It is also quite variable in colouration, the two common colours being red and green; an individual may change its colour during its life, as in the specimen shown which shifted from red to green. Large specimens of the form with frilly, webbed spines like flower petals are rare because the frills are exceedingly fragile and prone to damage; such specimens, especially when wholly red, are in great demand and command high prices. A grazing gastropod feeding on algae, it inhabits rocky surfaces of rather deep waters around -50~250m, its deep habitat contributed to its apparent rarity prior to the invention of tangle nets in the Philippines. Typical shell length around 60mm including spines, very large specimens may approach 100mm.
Spondylus regius Linnaeus, 1758 <br /> SPONDYLIDAE<br /> -60~80m, By lobster gillnets, Sakai, Minabe-Cho, Wakayama Prefecture, Japan, 1980/iii, 213.5mm <br /> <br /> The "Regal Thorny Oyster" is a glorious spondylid native to the western Pacific, ranging from Japan to Philippines. It is an exceedingly famous species and collector's item due to its large size, long spines, and gorgeous colouration; chosen by S. Peter Dance as one of his 50 "Rare Shells" (1969). Used to be a very rare species until the 20th Century but today it is a common shell, to the extent that it is often seen sold as home decoration. Giant or exceptional specimens, however, are still much prized and fetch high prices. Most specimens are reddish in colour with pale spines but uncommonly wholly orange specimens (as shown) are found, and rarely also yellow ones. Specimens from deep water often have very long spines which may be spatulate and undulating at tips, as well as more fine spines between the main ribs. This form has been given the name Spondylus cumingii Sowerby II, 1847, now considered a synonym of S. regius, and these are also much favoured by collectors. A sessile filter-feeding species living attached to hard substrates, it inhabits shallow to rather deep water ranging between -5~100m in depth. Typical shell length including spines 160mm, extremely large specimens may exceed 220mm. The depicted specimen is a superb deep water orange shell from Japan with all fine spines perfectly preserved.
Nodipecten magnificus (Sowerby I, 1835) <br /> PECTINIDAE<br /> -6~7m, Dived, Fernandina Island, Galápagos Islands, 2000/x, 97.2mm<br /> <br /> The "Magnificent Scallop" is a truly flamboyant pectinid and a famous endemic species of the Galápagos Islands. A much celebrated collector's item, it is a rarity on the shell trade market despite being locally not uncommon because Galápagos Islands is not only difficult to access but also a protected area with strict regulations implemented on collecting. A filter-feeding bivalve, it inhabits shallow sandy bottoms among reefs around -2~50m deep and often attaches itself to hard substrates using byssus threads. The number of ribs is generally between 12 and 13, quite numerous for the genus Nodipecten. Young shells (as shown) usually produce small nodules on the ribs as well as white markings but this stops after a certain size and ribs then become uniform in colouration and lack nodules. The normal colouration is a striking dark red but occasionally orange specimens are found, rarely also brown ones. Typical shell length around 170mm, very large specimens may exceed 220mm.
Beringius miyauchii Habe & Ito, 1972<br /> BUCCINIDAE<br /> -400~450m, Trawled, Off Urup Island, Kuril Islands, 2014/viii, 109.1mm<br /> <br /> The "Miyauchi's Neptune" is a cold-water buccinid with fascinating sculpture native to the Sea of Okhotsk, ranging from northern Hokkaido, Japan to the Kuril Islands. It is a very rare species and is extremely difficult to acquire in fine condition. Many consider it to be a form of Beringius frielei Dall, 1895 but it is clearly distinct from that species with much stronger sculpture, a much more slender shell, and shallower suture. It is also often treated as a subspecies of B. frielei, although this possibility cannot be excluded the geographical distribution of the two species overlap and it is perhaps best to consider them as separate species. A carnivorous and scavenging gastropod, it inhabits soft bottoms of rather deep water ranging between about -100~500m in depth. The apex is always corroded in adult specimens. Typical shell length around 100mm, very large specimens may exceed 130mm.
Austrasiatica hirasei (Roberts, 1913) <br /> CYPRAEIDAE<br /> -100~150m, Balut Island, Davao Occidental, Mindanao, Philippines, 2009/iv, 48.0mm <br /> <br /> The "Hirase's Cowrie" is an exceedingly elegant cypraeid ranging from Kii Peninsula, Japan to Philippines to Queensland, Australia. One of the 'three famed cowries' of Japan along with congener A. langfordi (Kuroda, 1938) and Nesiocypraea teramachii (Kuroda, 1938), it is a much coveted rarity and collector's item. Although in the recent years many specimens have surfaced from the East China Sea and those have been traded with relatively low prices, high quality specimens are still costly. Truly Australian specimens, especially, are extremely scarce. An omnivorous nocturnal gastropod, it inhabits relatively deep water around -100~200m. Typical shell length around 50mm, extremely large specimens may exceed 65mm. It is named in honour of the eminent pioneering Japanese collector Yoichiro Hirase. The first specimen is said to have been discovered from the hands of a young girl in the fishing village of Kii-Tanabe, Wakayama Prefecture, Japan; hence its wamei (Japanese vernacular name) is "Otome-dakara", meaning "Maiden Cowrie".
Otukaia kiheiziebisu (Otuka, 1939) <br /> CALLIOSTOMATIDAE<br /> -800~850m, Trawled, Off Minamisōma, Fukushima Prefecture, Japan, 2013/v, 35.1mm<br /> <br /> Characteristically ornamented with three pleating keels, the "Kiheizi's Top" is an extremely striking calliostomatid and a very famous classic rarity of Japan. It is endemic to Japan with its range restricted to the Pacific side of southern Hokkaido to Honshu to Shikoku. Although its feeding habits are not well known it is most likely a carnivorous grazer feeding on cnidarian and other sessile organisms. Most specimens are collected as trawling by-catch from soft bottoms of deep water around -200~1000 deep, but it is very rare throughout its range and is a highly sought after species. Typical shell length around 30mm, very large specimens as shown may exceed 35mm. It was christened 'kiheiziebisu' after a famous Japanese collector, Mr. Kiheizi Ōshima, who first collected it from the fish market of Chōshi, Chiba Prefecture; 'ebisu' literally means 'top shell' in Japanese. It is also the type species of genus Otukaia, as designated by Ikebe, 1942. Otukaia ikukoae Sakurai, 1994 is a southern form with finely granulated keels instead of smooth ones, it used to be considered as a separate species but is now understood as merely a form and thus treated as a junior synonym.
Zygochlamys delicatula (Hutton, 1873) <br /> PECTINIDAE<br /> -100m, Off Otago Peninsula, South Island, New Zealand, 1993/xii, 62.7mm<br /> <br /> The "Southern Queen Scallop" is a vividly coloured pectinid endemic to New Zealand, mainly distributed on the continental shelf of South Island, in the subantarctic waters southward of Kaikoura, Canterbury. Its size is large for the genus Zygochlamys, with an average shell length around 60mm and very large specimens exceeding 75mm. Due to this relatively large size and the fact that it is a rather abundant species, it is exploited commercially for food and is the only commercially important Zygochlamys species. A filter-feeding species living on soft bottoms, juveniles first settle attached on marine growth such as bryozoans or other mollusc shells. It is most abundant around moderate depths between -150~200m, but may be found across a wider bathymetric range of -70~300m. The colouration may vary from pastel yellow to reddish, and the upper valve is much more intensely coloured compared to the lower valve.
Spondylus echinatus Schreibers, 1793 <br /> SPONDYLIDAE<br /> Cebu Island, Central Visayas, Philippines, 1983/xii/27, 95.1mm<br /> <br /> Spondylus echinatus is a delightfully spined thorny oyster widely ranging across the Indo-West Pacific, south of Amami Islands, Japan. It is a very variable species in terms of spine development and colouration, which has resulted in a number of synonyms being given. A very famous one is Spondylus castus Reeve, 1856 and it is often still referred to as that, since it is listed in many books under that name. The brown shelled and white spined form as shown has been known as Spondylus albibarbatus Reeve, 1856. Both Anton, 1838 and Chenu, 1844 gave it the name Spondylus albus, but both are synonyms. Furthermore, a densely spinous form was given the name Spondylus spectrum Reeve, 1856. The juvenile shell is characteristically white with small black patches. A filter-feeding bivalve which lives a sessile lifestyle with the right valve attached on hard substrates, it is a common species found from low intertidal zone down to about -20m deep. Typical shell length around 90mm, very large specimens may exceed 130mm. Spondylus zonalis Lamarck, 1819 was traditionally considered to be a form of this species, but is now considered to be a separate full species in its own right.
Haliotis midae Linnaeus, 1758 <br /> HALIOTIDAE<br /> South Africa, 175.1mm<br /> <br /> The "Midas Ear Abalone", locally known as "Perlemoen", is a large haliotid endemic to South Africa with a beautifully radiating wave-like sculpture. A grazing gastropod feeding primarily on encrusting algae as juveniles and a variety of seaweed and drift algae as adults, it is a common species inhabiting moderately exposed rocky shores from intertidal waters down to about -30m deep. It is the only commercially important abalone species in South Africa, traditionally harvested for the meat and exported to Asian markets where the demand for its meat is very high. Since the 1960s it started to show signs of over-exploitation, and the stocks declined rapidly after entering the 21st Century leading to the South African government closing the fishery completely in February 2008. For the same reason it was listed in CITES Appendix III by South Africa on May 2007, although it was then deleted on June 2010. Nevertheless, illegal fishing and poaching continues today and products are often exported from nearby countries such as Namibia and Mozambique. Captive-bred aquacultural business also exist, producing live specimens often seen for sale on the markets of Hong Kong and China. Its shell is commonly sold as home decor in the polished and dyed state, natural shells in good condition are surprisingly difficult to find. In its natural habitat it is usually heavily encruscted by marine overgrowth and the characteristic undulating sculpture is often completely concealed. The dorsum colouration may vary from yellowish to dark red, the internal is iridescent and often carry bluish patches in large specimens. Typical shell length around 150mm, extremely large specimens may exceed even 220mm.
Cardita crassicosta Lamarck, 1819 <br /> CARDITIDAE<br /> -10~25m, Zamboanga, Zamboanga Peninsula, Mindanao, Philippines, 2013, 45.3mm<br /> <br /> The "Large-Ribbed Cardita" is an exceedingly beautiful and colourful western Pacific carditid ranging from Taiwan to Indonesia to Australia. It is tremendously variable in colouration which can be anything from white to red to yellow to violet to very dark brown, and is therefore popular among collectors to collect a set of many specimens to exhibit the whole palette. Although it is a common species some colour forms, such as purple, are rare. The form and sculpture is generally quite consistent; specimens may or may not have dark lines on top of their base colours, in most cases between ribs but sometimes also over the ribs. A suspension feeding bivalve, it inhabits sandy bottoms of intertidal and shallow subtidal waters down to about -40m deep. Typical shell length around 45mm, extremely large specimens may exceed even 70mm.
Fissidentalium metivieri Scarabino, 1995 <br /> DENTALIIDAE<br /> -200~250m, Trawled, Madagascar, 2000/x, 126.0mm<br /> <br /> The "Metivier's Tusk" is an elegantly curved tusk shell with a restricted distribution in the southwest Indian Ocean, virtually all known specimens originate from rather deep water of -200~800m around Madagascar where it is locally not uncommon. With the largest specimens exceeding 180mm in shell length it is the largest of all currently known recent scaphopod or tusk shell species. Typical specimens are much smaller and average at around 130mm, but even that is extremely large for a scaphopod. A selective deposit-feeder like other dentaliids, it presumably feeds on small organisms such as diatoms and foramniferans and lives almost completely buried head-down in soft bottoms, leaving only the very posterior tip of its shell for water exchange and waste expulsion. It locates food using the numerous ciliated tentacles, known as captacula, surrounding the head. The captacula uses cilia to transport smaller food particles and can also retract to bring larger food items to the mouth. Although the curvedness of the shell may vary slightly, it is generally consistent in both the sculpture and the white colouration. The apex or posterior aperture is characterised by a slit-like opening in this species.
Harpa costata (Linnaeus, 1758) <br /> HARPIDAE<br /> -4~5m, Mauritius, 2009/x, 64.5mm<br /> <br /> The illustrous shell of the "Imperial Harp", with its elegantly ornamentation of numerous ribs, is arguably one of the most fascinating and elegant of all molluscs. Though it is a classic rarity chosen by S. Peter Dance as one of his fifty "Rare Shells" (1969), it was only truly rare before the early 1900s when its provenance was revaled in Mauritius. Today we know its distribution is indeed a very restricted one in the Mascarene Basin, ranging from Mauritius to Reunion to eastern Madagascar; vast majority of specimens originate from Mauritius, where it is probably best described as locally uncommon. However, as there are legal restrictions to collecting in Mauritius and the fact that high quality specimens are scarce, its price remains high and continues to be one of the most sought-after species in Harpidae. Like other Harpa species it is a carnivorous and predatory gastropod feeding on small crustaceans, mainly crabs, and it inhabits sandy bottoms of shallow water down to about -15m deep. Typical shell length around 65mm, though the largest specimen known reaches a staggering size of 111mm. Though it is an unmistakable, instantly recognisable species with a little-varied general form, the width and frequency of ribs vary greatly. This led to a form with widely spaced ribs being described as Harpa laetifica Melvill, 1916, and a form with very dense ribs was given the name Harpa multicostata Sowerby I, 1822; both are now considered to be synonyms. Another well-known synonym is Harpa imperialis Lamarck, 1822, from which its common name originate. Furthermore, a local form from southeast Madagascar with supposedly stronger-than-usual yellow colouration in the aperture was recently named Harpa costata f. lutea Bozzetti, 2012; but this was described as a form and thus carries no taxonomic validity under the current International Code of Zoological Nomenclature.
Vulsella vulsella (Linnaeus, 1758) <br /> PTERIIDAE<br /> -10~25m, Bohol Island, Central Visayas, Philippines, 2013, 80.6mm<br /> <br /> The "Sponge Finger" is a strange pteriid with a most interesting way of life of being embedded in sponges. This extraordinary sponge-bivalve relationship is obligatory and host-specific with the host being Spongia sp., an undescribed species, and is believed to be mutually beneficial to both animals. The bivalve settles on the sponge, and then remarkably loses the byssus to rely on the sponge for life, becoming endozoic. A cluster of Vulsella serves as an endoskeleton for the sponge to grow, while the sponge covers them and protect them from potential predators. Recent studies further revealed that the sponge builds an internal canal system to take advantage of the bivalve's exhalent flow and increase its own filtering rate -- the two filter-feeding species work together to gather food more efficiently. This phenomenon is commonly observed across the very wide range of V. vulsella across the Indo-West Pacific, southwards from Honshu, Japan; in shallow water around -2~30m in depth. Its shape and pattern is very variable but larger individuals tend to grow long shells resembling a finger, hence its common name. Typical shell length around 70mm, very large specimens may exceed even 115mm. Though Vulsella's true systematic position has always been a topic of debate (some even gave it its own family, Vulsellidae), it was traditionally placed in Malleidae. Recent phylogenetic studies of the superfamily Pterioidea, however, revealed it to be distant from the true Malleidae but closer related to a mixed Pteriidae-Isognomonidae clade. Isognomonidae was thus synonymised with Pteriidae, and Vulsella was moved to Pteriidae.
Ceratostoma foliatum (Gmelin, 1791) <br /> MURICIDAE<br /> -6~12m (-20~40 ft), SCUBA dived on rocks, Cuyler Harbour, San Miguel Island, Channel Islands, Off Santa Barbara, California, USA, Coll. Rick Negus, 1991/viii, 59.4mm<br /> <br /> The "Leafy Hornmouth" is a gorgeously winged northeastern Pacific murex ranging from Alaska, USA to British Columbia, Canada to California, USA; it is perhaps best known from California, where it is a representative member of a great muricid diversity. A carnivorous and predatory gastropod mostly feeding on bivalves and barnacles, it is found on rocky substrates from the lower intertidal zone down to about -60m deep. Although not uncommon, it is not easy to find a collectible specimen with both good size and wings. The colouration can range from white to dark brown with banded specimens also occuring and is variable regardless of locality. The form, especially of the varices, is very variable but more consistent according to environment and locality; for example in southern California most specimens have flat flanged varices while those from northern Channel Islands (as shown) have strongly fluted varices that resemble Ceratostoma burnetti (Adams & Reeve, 1849) from western Pacific. The extent of varice development also varies according to the environment and thus locality. Typical shell length around 60mm, very large specimens may exceed 100mm.
Foegia novaezelandiae (Bruguière, 1789) <br /> PENICILLIDAE<br /> Subtidal from sand and rubble bottom, Shelly Beach, Pallarenda, Queensland, Australia, 68.2mm<br /> <br /> Foegia novaezelandiae is a small watering-pot clam best known from Western Australia but also recorded from Japan; although it bears the name "novaezelandiae" it is actually not found in New Zealand. It is a adventitious tube-building bivalve like other members of the superfamily Clavagelloidea, which in the very earliest stages of life bears a normal bivalved shell but soon stops growing it and switches to building a calcareous tube. A locally common filter-feeding species, it inhabits soft bottoms of shallow intertidal and subtidal water to -10m deep and lives vertically buried with the "watering-pot" end down. It is unique among the family to inhait hypoxic sediments and may be associated with chemoautotrophic bacteria, which forms a thin layer on its pedal disc. The true shells are largely hidden from surface of the tube in this species, as it is mostly covered by the secreted tube material. It is the type species of genus Foegia and since a new genus, Kendrickiana, was erected to house K. veitchi (Smith, 1971) it is the only species remaining in that genus. The typical length of the adventitious tube is around 80mm, very large specimens may exceed 100mm.
Babylonia pieroangelai Cossignani, 2008 <br /> BABYLONIIDAE<br /> -160m, Trawled, East China Sea, 2015, 83.4mm<br /> <br /> Babylonia pieroangelai is a large and eye-catching babyloniid ranging from southern Japan to East China Sea to Taiwan, characterised by a strongly toothed fasciole. It was recently separated from the superficially similar Babylonia perforata (Sowerby II, 1870) based on its deeper suture, much more angulated shoulder, larger size, and more elongated form. Though still considered by some as a subspecies or even synonym of B. perforata, generally it is accepted as a valid species in its own right for now; understanding the true relationship between these two names require further evidence. Distribution of the two do not overlap, with B. perforata having a more southwesternly restricted distribution from Burma to Thailand to Cambodia. It is an uncommon carnivorous and scavenging gastropod inhabiting sandy to muddy bottoms, its depth range is around -100~200m which is very deep for the genus Babylonia. Typical shell length around 75mm, very large specimens may exceed 85mm.
Volva volva (Linnaeus, 1758) <br /> OVULIDAE<br /> Punta Engaño, Lapu-Lapu city, Mactan, Central Visayas, Philippines, 2009/viii, 136.0mm<br /> The "Shuttle volva" is an unusual ovulid with both anterior and posterior siphonal canal elegantly and distinctly extended. Thanks to these it attains the largest size of all known recent ovulids, with an average shell length of around 100mm and the very largest exceeding even 180mm; though the size is quite variable among individuals. A carnivore and an ectoparasite of octocorals, it particularly favours members of the family Veretillidae as its host. Naturally it is associated with veretillid octocorals and often found living on them, in shallow to moderately deep sublittoral water around -10~200m in depth. It is a common species with a very wide range across the Indo-West Pacific, it can be found from Eastern Africa to the southern half of Japan to Australia. Though the shell is easily recognisable, the siphonal canals are rather variable and may be strongly bent and the body whorl is sometimes weakly angulated. It should be easily separable from other recognised Volva species by its typically much longer siphonal canals.
Haustellum kurodai (Shikama, 1964)<br /> MURICIDAE<br /> -80~100m, By tangle nets, Panglao Island, Bohol, Philippines, 2007/xi, 111.4mm<br /> The "Kuroda's Snipe's Bill" is an elegant Western Pacific muricid with a long siphonal canal, ranging from the Arafura Sea to the Philippines. A carnivorous and predatory gastropod, it is nocturnal and inhabits sandy bottoms around -10~80m deep. Though some authors used to consider it a synonym of Haustellum haustellum (Linnaeus, 1758), it is actually clearly separable from that species based on shell characteristics, especially the protoconch which is characteristic of lecithotrophy in H. kurodai and planktotrophy in H. haustellum. It is most similar and sometimes confused with another Philippines species, H. vicdani, which differs by having a completely smooth siphonal canal with no spines, as well as having a generally more purple colouration. Typical shell length around 120mm, very large specimens may exceed 145mm.
Ginebis crumpii (Pilsbry, 1893) <br /> CALLIOTROPIDAE<br /> -300~350m, Trawled off Tosa, Kōchi Prefecture, Shikoku, Japan, 1990/x, 31.5mm<br /> The "Crump's Margarite" is a striking calliotropid with a pearly surface attractively ornamented by rows of spiny knobs. Ranging from Honshu, Japan to East China Sea to Taiwan, it is a deposit feeder inhabiting sandy to gravely bottoms of rather deep water around -50~300m. Although an uncommon species, its supplies have recently increased significantly as specimens are frequently turning up as by-catch from Chinese fishing vessels. A rather small Ginebis, its typical shell length is around 30mm with very large specimens exceeding 40mm. The genus name Ginebis literally means "silvery top" in Japanese.
Timbellus miyokoae (Kosuge, 1979) <br /> MURICIDAE<br /> -50m, By Dave Aque from tangle nets, Samal Island, Davao Region, Mindanao, Philippines, 2008/i, 61.4mm<br /> <br /> The "Miyoko Murex" is a highly sought-after muricid with spectacular wing-like varices. First described from Mactan Island, Philippines, almost all known records are from within the Philippines; although specimens attributed to the same name have been found as far as the Solomon Islands. The normal colouration of the Philippines shells is rusty brown overlaid by some white hands, but the Solomon shells are pure white. When first described and few speciemns were available, many considered it as a form of the superficially similar Pterynotus loebbeckei (Kobelt, 1879). As more specimens surfaced, however, its status as a distinct species became undeniable. Today it is no longer rare, in fact it is known to be quite common in the Philippines and even specimens with very good wings have become easily obtainable. A carnivorous and predatory gastropod feeding on bivalves and other invertebrate animals, it inhabits rather deep water around -50~200m in depth. Typical shell length around 60mm, very large specimens may reach 75mm. Though originally described in the genus Pterynotus, it was recently moved to Timbellus, its current genus.
Mikadotrochus hirasei (Pilsbry, 1903) <br /> PLEUROTOMARIIDAE<br /> -200m, Off Ukujima, Gotō Islands, Nagasaki Prefecture, Japan, 98.1mm, 2001/x<br /> <br /> The "Hirase's Slit Shell" is a thick-shelled pleurotomariid with flamboyant flame-like patterns, native to the Western Pacific. It generally ranges from central Honshu, Japan to East China Sea and Taiwan, though very rare records exist from as far south as the Philippines. A carnivorous grazer feeding on sponges and soft corals, it is found in rather deep water around -50~300m. As it is a relatively common species especially from Japan to East China Sea and frequently brought up as by-catch in this area, it is a famous species and perhaps the most easily obtained species of the slit shells, most species of which are very rare and difficult to obtain. Quite variable in shell form especially the height/width ratio and the swollenness of whorls though rather consistent in sculpture and pattern, the name M. h. yamamotoi Yamamoto, 1993 is a synonym given to a compressed form. An uncommon albinistic form is known across its range. Typical shell diameter is around 70mm, very large specimens may exceed 120mm. It is most similar to the much rarer Mikadotrochus beyrichii (Hilgendorf, 1877) endemic to Japan, but they are easily distinguished by boths sculpture and pattern.
Lobatus goliath (Schröter, 1805) <br /> STROMBIDAE<br /> Dived, Natal, Rio Grande do Norte, Brazil, 305.0mm<br /> With an average shell length of 300mm and a staggering record size of 380mm, the aptly named "Goliath Conch" is the largest strombid species alive today. A herbivorous gastropod living in shallow water down to about -50m deep, it is found mostly on sandy bottoms and primarily feeds on algae and seagrass. Although generally considered to be endemic to Brazil, recent findings reported the presence of two small populations in Barbados as well, presumably recently settled through a rare dispersal event. Its handsome shell is distinctively adorned with a very extensively flared outer lip and thin layer of golden brown periostracum. During recent years it has been moved around a few genera as part of the extensive revision of the family Strombidae, including Strombus, Eustrombus, Titanostrombus, before finally settling in Lobatus, its current genus. Though a locally common species in Brazil, it is not easy to acquire a large and operculated specimen with a perfect, unfiled lip.
Pseudovertagus nobilis (Reeve, 1855) <br /> CERITHIIDAE<br /> -20m, Bohol Island, Central Visayas, Philippines, 127.5mm<br /> The "Noble Creeper" is a lovely and large cerithiid widely ranging in the Indo-West Pacific region from Mozambique / Madagascar to Tahiti and best known from the Philippines. A common species feeding on algae and detritus, it inhabits sandy to rubbly bottoms around -10~80m deep. It is a little-varied species and its shiny, smooth surface and the delicate columellar lip behind the rather long, elegantly recurved siphonal canal renders it unmistakable even among other Pseudovergatus species. Typical shell length around 130mm, very large specimens may even exceed 170mm. That makes it not only the largest Pseudovergatus species, but also one of the largest extant members of the family Cerithiidae.
Calliostoma springeri Clench & Turner, 1960<br /> CALLIOSTOMATIDAE<br /> -500m, Florida, USA, 29.0mm, F+, Ex-coll. Andrea Nappo<br /> The "Springer's Top" is an attractively beaded and showy calliostomatid native to the Carribean region ranging from Florida, USA to the Gulf of Mexico. An uncommon to rare species much sought-after by collectors, it inhabits relatively deep water around -200~500m. Although presumably a carnivorous grazer like most other deep-water calliostomatids, little is known about its ecology. Somewhat variable in form especially according to age, small specimens usually have much stronger keel on their body whorl. The shell surface carries a golden iridescence and is quite shiny. Typical shell diameter around 20~25mm, very large specimens may exceed 30mm. Though often treated as a subspecies or form of Calliostoma benedicti Dall, 1889, the holotype of C. benedicti is quite different in being much smaller (17.5mm shell diameter) than the average C. springeri and has a much smaller umbilicus. It is also much lighter in colouration, though this may be due to status of preservation. Most specimens sold as C. benedicti on the market match C. springeri well and do not match C. benedicti; the true C. benedicti appears to be extremely elusive. It is possible that the holotype of C. benedicti is an unusual form of the same species as C. springeri, but more investigation is needed to decide the true relationship between these two names.
Vasula melones (Duclos, 1832) <br /> MURICIDAE<br /> Lowtide on rocky substrate inside reef crevice, Jacó, Costa Rica, 1972, 41.8mm, F++<br /> The "Gourd Rock Shell" is a common muricid inhabiting intertidal to shallow littoral rocky shores of Pacific Ocean, ranging from Mexico to Peru including the Galápagos Islands. A carnivorous gastropod, it preys upon a wide variety of other invertebrates such as bivalves, gastropods, and polychaetes. Although generally spherical in form with a very inflated body whorl, morphology of the shoulder is rather variable and some individuals have angled, raised shoulder. The colouration consists of variable amount of dark brown to black blotches on a cream background, and is very variable among individuals. Typical shell length around 40mm, very large specimens may exceed 60mm.
Cancellaria indentata Sowerby I, 1832 <br /> CANCELLARIIDAE<br /> -37m (-20 fms), From shrimp fisherman, Gulf of California, Topolobampo, Sinaloa, Mexico, 31.2mm<br /> The "Toothed Nutmeg" is an attractive cancellarid with strong axial and radial ridges forming raised mesh-like sculpture, typical of the family. An eastern Pacific species, its distribution ranges from Gulf of California to Ecuador (including the Galápagos Islands) and is a suctorial-feeding carnivorous gastropod inhabiting hard surfaces from -10m down to about -100m deep. A locally common species, the shell length averages at about 30mm but extremely large examples may exceed 40mm. The strength of sculpture is somewhat variable but overall it is a little-varied and easily recognised species.
Guildfordia triumphans (Philippi, 1841) <br /> TURBINIDAE<br /> -100~200m, Ilan County, Taiwan, 58.4mm<br /> The "Triumphant Star Turban" is a striking turbinid with a 'star-burst' arrangement of spines. Though its wide range extends from Japan to south as far as Queensland, Australia, it is often regarded as a symbolic species of Japan and is depicted on the logo of the Malacological Society of Japan. It is a hervivorous / detritivorous gastropod inhabiting sandy to muddy bottoms of moderately deep water around -100~300m. A common species throughout its range, although specimens with all spines intact are uncommon. Typical shell length around 45mm, very large specimens may exceed 65mm. In genus Guildfordia it usually has an intermediate spine length between the other two common species G. aculeata Kosuge, 1979 and Guildfordia yoka Jousseaume, 1888; and is usually easily recognised from the spine length.
Epitonium ancillotoi Cossignani & Cossignani, 1998 <br /> EPITONIIDAE<br /> -100~150m, From tangle nets, Balut Island, Davao Occidental, Philippines, 26.5mm<br /> Epitonium ancillotoi is a lovely wentletrap with delicate varices known from Philippines to Australia, with vast majority of specimens originating from Philippines. A moderately common carnivorous gastropod, it feeds exclusively on sea anemone like many epitoniids do. It inhabits sandy bottoms around the depth of -10~150m and is found closely associated with the sea anemone species which it feeds on, such as Heteractis crispa (Ehrenberg, 1834) and Macrodactyla doreensis (Quoy & Gaimard, 1833). It closely resembles Epitonium irregulare (Sowerby II, 1844) and often mistaken for it, but E. irregulare has smooth intervarical spaces lacking the dense fine spiral lines that characterise E. ancillottoi. The shell is most often uniformly white in colour, although some specimens carry irregular brown patches (as shown). Typical shell length around 30mm, very large specimens may exceed 40mm.
Coronium acanthodes (Watson, 1882) <br /> MURICIDAE<br /> Trawled from deep water, Argentina, 65.1mm, F<br /> The "Watson's Trophon" is a prickly muricid native to the temperate southwestern Pacific ranging from southern Brazil to Falkland Islands to Chile, with some records off the Antarctic Peninsula also. A carnivorous and predatory gastropod, it inhabits soft bottoms of rather deep water around -80~400m. The yellowish white colouration, general form, and sculpture is usually consistent but development of varices varies among individuals. Originally placed in the genus Trophon, it was recently reassigned to Coronium based on protoconch and egg capsule morphology, both of which resemble Coronium coronatum (Penna-Neme & Leme, 1978). It is a large trophon, perhaps the largest in the region, with an average shell length of 80mm and giants may reach 120mm.
Triplodon corrugatus (Lamarck, 1819)<br /> HYRIIDAE<br /> -2m, By local divers, Amazon River, Macapá, Amapá, Brazil, 76.8mm<br /> Triplodon corrugatus is a marvelously shaped unionoid freshwater mussel native to northern South America, ranging from Brazil to Peru to Venezuela, including the Amazon basin. Although characterised by the raised wing-like projections in both posterior and anterior parts of both valves, the extent of these projections actually vary greatly among individuals. It is a locally common filter-feeding bivalve inhabiting soft sediments of shallow freshwater habitats. As is the norm in unionoids it is known to go through a glochidia larval stage parasitising fish gills/fins before settling down to assume an adult life style. Typical shell length around 80mm, very large specimens may exceed 120mm.
Calliostoma canaliculatum (Lightfoot, 1786) <br /> CALLIOSTOMATIDAE<br /> -1.5~3m (-5~10 ft), SCUBA dived on kelp (Macrocystis sp.) growing from seabed -10.5m (-35 ft) deep, Santa Cruz, California, USA, 30.2mm, F+<br /> Characterised by numerous strong spiral cords and a sharply keeled base, the "Channeled Top Shell" is a handsome eastern Pacific calliostomatid ranging from southern Alaska, USA to Baja California, Mexico. A moderately common omnivorous gastropod mainly feeding on hydroids and bryozoans, it is part of the kelp forest community and is usually seen in the shallow canopy of kelp plants to about -20m deep. Its main predator is seastar and it is known to secrete a toxic, yellowish mucus as a defence mechanism upon contact with a seastar. Typical shell length around 30mm, very large specimens may exceed 40mm.
Boreotrophon xestra Dall, 1918 <br /> MURICIDAE<br /> -80~200m, From shrimp nets, Jumunjin, Gangneung, Gangwon-do, South Korea, 48.1mm, F++<br /> Boreotrophon xestra is a delicately beautiful muricid ranging from Sea of Japan and the northern half of Pacific Japan to Kuril Islands and Bering Sea. A somewhat uncommon predatory gastropod, it inhabits sandy to muddy bottoms of rather deep water around -100~400m. The shell, especially the shouldered varices, are very fragile and susceptible to erosion; good quality specimens are therefore quite hard to obtain. The siphonal canal may be straight or curved to left. Typical shell length around 30mm, extremely large specimens sometimes exceed 45mm.
Boreotrophon pacificus Dall, 1902<br /> MURICIDAE<br /> -80~200m, From shrimp nets, Jumunjin, Gangneung, Gangwon-do, South Korea, 40.5mm, F++<br /> The "Northwest Pacific Trophon" is an attractively scultpured muricid supposedly ranging widely from Sea of Japan to Bering Sea to Pacific coast of USA, but best known from the northwest Pacific including Japan and Russia. A predatory gastropod inhabiting sandy to muddy bottoms, it is found from shallow subtidal waters down to about -200m deep. The colouration varies from white to yellowish, and it is also varable in number of varices per whorl as well as direction of the anterior siphonal canal. Though locally rather common, the shell is fragile and often eroded, making quality specimens uncommon. Typical shell length around 20mm, very large specimens may exceed 40mm.
Turriconus excelsus (Sowerby III, 1908) <br /> CONIDAE<br /> -150~200m, From tangle net, Balut Island, Davao Occidental, Philippines, 73.5mm, F++<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 feeding on polychaete worms 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 trio of three famed cones characterised by tall, stepped spires; the other two being Cylinder gloriamaris and Leptoconus milneedwardsi.
Conchocele bisecta (Conrad, 1849) <br /> THYASIRIDAE<br /> -250~350m, On mud bottom, By tangle nets, Off eastern South Korea, 20.2mm, F++<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 (as shown here), but becomes flat to strongly concave in adults. Adult shells are also more elongated 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.
Ceratostoma burnetti (Adams & Reeve, 1849) <br /> MURICIDAE<br /> -25m, Dived on mussel bed, Busan, South Korea, 99.8mm, F++<br /> The "Burnett's Murex" is a showy muricid with extensive wing-like varices. Ranging from Yellow Sea to the Russian Aleutians, it is most famously known from South Korea for which it has become a symbolic species. A carnivorous and predatory gastropod feeding on bivalve molluscs such as oysters, it inhabits hard substrates and bivalve beds from intertidal waters down to about -40m deep. Though once considered a classic rarity, it is now known to be rather common in its local habitat especially in South Korea and Japan. It is actually very variable in varice development, fine quality specimens with wide and intact varices (mostly from South Korea) are uncommon; the short-winged form has been described as f. coreanica (Adams, 1854) and is considerably rarer. The colouration is usually beige but may vary from whiteish to very dark brown, a banded form also occurs but only very rarely. Typical shell length around 90mm, extremely large specimens are known to exceed 130mm.
Carinaria cristata (Linnaeus, 1767) <br /> CARINARIIDAE<br /> Shallow water, southern part of Mozambique, 39.0mm, F<br /> The elegant "Glassy Nautilus" is a classic rarity of historical fame in shell collecting, chosen by S. Peter Dance as one of the four famous rarities in his "Shell Collecting: An Illustrated History" (1966). Its strange form and beauty attracted attention of conchologists at once since its description and for more than 100 years from the mid-18th to 19th Century it was one of the most coveted species of all, comparable to Cylindrus gloriamaris (Chemnitz, 1777), with prices reaching 3,000 livres. Since the beginning of the 20th Century, however, it has become much forgotten by the collecting community. The extremely fragile and highly translucent shell is minute compared to the impressively sized animal that is not only the largest Carinaria but also the largest heteropod of all, attaining a body length over 680mm. A holoplanktic (i.e., planktic for its entire life) pelagic gastropod with a very wide range covering the entire Indo-Pacific, it is an active predator of a variety of zooplankton, mainly thaliaceans, chaetognaths, copepods, and other planktic gastropods. Like most planktic gastropod it migrates vertically through the water column diurnally and may thus be found from the sea surface down to a few hundred metres deep. The shell is still rarely seen in the market today especially with intact protoconch and decent aperture, but much of this apparent rarity is due to the lack of attention and demand it had once received as the animal is not uncommon in its natural environment. Typical shell length around 35mm, very large specimens may exceed 70mm. The protoconch is tightly coiled but the teleoconch relaxes to a slightly curved pyramidal cap; it can be distinguished from other Carinaria species by the less curved shell and the extremely low keel.
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