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.

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.

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.

Pionoconus gauguini (Richard & Salvat, 1973)<br />
CONIDAE<br />
Marquesas, French Polynesia, 2012/x, 70.4mm <br />
<br />
With a very limited distribution range from Marquesas Islands to Tahiti and Society Islands, the "Gauguin's Cone" is one of many stunning conids endemic to the French Polynesia. An uncommon to rare species, it is much coveted by shell collectors and command high prices in the shell trade. A carnivorous and predatory gastropod that actively hunts polychaete worms, it inhabits sand to rubble bottoms of coral reefs around -15~40m deep. It is nocturnal and spends daytime buried in sand under slabs of rocks or coral. The colouration varies from light pink to dark purple, brown to black blotches of various sizes are sometimes present. Typical shell length around 65mm, extremely large specimens may exceed 90mm. It is conchologically very similar to Pionoconus barthelemyi from western to central Indian Ocean, despite the great distances separating the two. Compared to P. barthelemyi, P. gauguini has a smoother shell surface and a more sharply carinate shoulder. Furthermore, the surface colouration of P. barthelemyi is generally orange to red whereas it is pink to violet in P. gauguini.

Here's a "shell" which deceives.... :)<br />
<br />
Stylobates aeneus Dall, 1903 <br />
ACTINIIDAE<br />
-600m (-2000ft.), From shrimp traps, Off northern Oahu Island, Hawaii, USA, 2003/iii, 56.7mm <br />
<br />
Superficially, the "shell" of Stylobates aeneus looks exactly like a gastropod shell, complete with an umbilicus. Quite understandably, it was initially described by Dall as a trochid. It is however not produced by a mollusc at all -- instead it is the work of a rather rare shell-forming actiniid sea anemone (Cnidaria: Anthozoa) capable of secreting a proteinaceous "shell" made of chitin, termed "carcinoecium" (i.e., "house of crustacean"). After examining further specimens, Dall realised his mistake and published a short note in 1919 to correct his erroneous phylum placement. A deep-water anthozoan, it inhabits sandy bottoms around -400~800m deep and lives obligately in association with hermit crab hosts, the host species being Sympagurus dofleini (Balss, 1912). This is considered to be a case of mutually beneficial symbiosis: by living on the back of hermit crabs, Stylobates gains a means of transportation as well as food scraps from the hermit crab; while the hermit crab gains protection from predators by the sea anemone's nematocysts (stinging cells). Members of the genus Stylobates (four described so far) are the only sea anemone known to have the capability of producing entire "shells" for their hermit crab hosts, although some others are known to extend the existing shell slightly. Still, Stylobates must first settle on an existing gastropod shell, from where it starts the shell making process. Therefore at the apex of the carcinoecium a true gastropod shell can always be found. Being able to make a shell for the host means the hermit crab no longer needs to find replacement shells as it grows, thus forming life-long relationships with the sea anemone. Stylobates aeneus was originally described from Hawaii but its distribution is now known to reach Guam. Specimens collected in Japan are generally also referred to S. aeneus and share the same host species, Sympagurus dofleini, but these differ in some aspects of the morphology and may represent a different species. Typical width of the carcoenecium is around 50mm, very large specimens may reach 80mm. Fresh carcinoecia are gold to bronze in colouration but over time those preserved dry often darkens and conversely specimens fixed in alcohol may lighten. The carcinoecium is very thin and fragile as it does not possess a calcium carbonate layer, to the extent that it often collapses when the host hermit crab is removed. Intact specimens of the carcinoecia are therefore rarely seen.

Mirapecten cranmerorum (Waller, 1986) <br />
PECTINIDAE<br />
-150~200m, Trawled, Off Somalia, 2008/x, 71.2mm <br />
<br />
Mirapecten cranmerorum is a gorgeous pectinid endemic to waters off eastern Somalia. A greatly coveted rarity and collector's item, much of its apparent scarcity now is due to its limited distribution in the Somali waters where piracy is a real threat. Once ago it was only uncommon and much less costly to obtain, when occasional supplies brought considerable numbers to Europe. Sparse scales are present only on the left valve, which is usually darker coloured and slightly more convex compared to the right valve. The colouration varies slightly from orange to red and the patterning differs among individual specimens. A filter-feeding bivalve, it inhabits hard bottoms on moderately deep waters around -80~200m. Typical shell length around 60mm, very large specimens may exceed 80mm. A new genus, Somalipecten, was proposed for it as part of the original description but this is now considered to be a junior synonym of Mirapecten.

Neocancilla takiisaoi (Kuroda, 1959) <br />
MITRIDAE<br />
-20~30m, Dived, Zampa-misaki (Bolo Point), Okinawa Island, Japan, 2002/x, 50.0mm <br />
<br />
With a wonderful combination of triangular 'tent' pattern and cancellate sculpture, the unmistakable "Isao Taki Mitre" is one of the most exquisite mitrids in the world. Widely distributed in the Western Pacific ranging from Japan to New Zealand to as far east as Pitcairn Islands, its type locality is Hachijō-jima, Japan and most specimens appear to originate from either southern Japan or New Caledonia. Its beauty and the fact that it is a very scarce species makes it one of the most desired mitres of all, made famous by featuring in "World Seashells of Rarity and Beauty" (1991) depicting a shell from the R. Kawamura collection, as well as T.C. Lan's "The Classic Shells of the World" (1993). It is sometimes beached, albeit very rarely and usually in poor condition. A carnivorous and predatory gastropod presumably feeding on sipunculid worms, it inhabits sand or rubble bottoms of moderate depths around -20~100m. Typical shell length around 45mm, extremely large specimens may reach 65mm. It is named in honour of Dr. Isao Taki (1898-1961) who was an influencial malacologist and zoologist in Japan, along with his younger brother Dr. Iwao Taki (1901-1984).

Zoila jeaniana (Cate, 1968) <br />
CYPRAEIDAE<br />
-20~40m, On sponge, Dived, Shark Bay, Western Australia, Australia, 2005/i, 64.3mm <br />
<br />
The "Jean's Cowrie" is a delightfully patterned cypraeid endemic to Western Australia, Australia; ranging between the Montebello Islands in the north and around Kalbarri in the south. It can be differentiated with other similar Zoila species by the presence of columellar dentition and a base with uniform orange to brown colouration, bounded by a pale margin. Like almost all Zoila species, it has been divided into many forms/subspecies. The nominal form is moderately rare and usually trawled from around -80~150m deep, occasionally found as shallow as -40m. The form sherylae Raybaudi, 1990 (shown here) from Shark Bay area is only uncommon due to its shallower depth around -20~60m, and is generally smaller than the nominal form. The rare form thalamega (Lorenz, 2002) consists the southmost population around Kalbarri; it inhabits shallower depths around -20~80m and is characterised by more elongate shell with rostrate tips. The name aurata Raybaudi, 1979 refers to rare deep-water shells trawled from -150~250m around northern Western Australia, characterised by much paler and typically golden colouration. It used to be treated as a valid subspecies but genetic examination in the recent years could not differentiate it from the nominate subspecies; it is currently treated as taxon inquirendum but in reality is probably merely a deep-water variation and not worthy of a subspecific rank. It is a carnivorous grazer feeding solely on demosponges, as is typical for Zoila. Typical shell length around 75mm, very large specimens may reach 110mm. It is named after Mrs. Jean Cate, wife of the Cypraeoidea specialist Crawford N. Cate who desribed this species.

Janthina janthina (Linnaeus, 1758) <br />
JANTHINIDAE<br />
Beached, Dampier, Western Australia, Australia, 2003/i, 33.0mm <br />
<br />
The "Common Violet Snail" is a gorgeously coloured janthinid with an extremely wide distribution across the world's warm and temperate seas due to their wholly pelagic lifestyle. The foot is specialised in making air rafts from mucus which enables it to float the on sea surface, usually apex-down. The splendid colouration is thought to be a camouflage to match the colouration of surrounding seawater. Furthermore, its shell is lighter coloured above the suture, considered as an example of counter-shading to make it blend in to seawater and difficult to find for predators when seen from below. It is a hermaphrodite exhibiting protandrous hermaphroditism, meaning each individual begin life as a male and then changes sex to female at a later stage; thus small individuals are males and large individuals are females. A predatory snail feeding on pelagic jellyfish encountered on the sea surface, two common preys include the pelagic hydrozoans "By-the-wind Sailor" Velella velella (Linnaeus, 1758) and "Portuguese Man O' War" Physalia physalis (Linnaeus, 1758). It is common and often occurs in large aggregations of dozens of individuals. In events of strong winds or storms whole aggregations are frequently stranded and beached; such events are greatly prized by beachcombers as it is otherwise only rarely beached. Typical shell width around 30mm, extremely large specimens may grow to 45mm.

Mitra hayashii (Kira, 1959) <br />
MITRIDAE<br />
Off Saga, Saga Prefecture, Japan, 1990/vi, 54.0mm <br />
<br />
The "Hayashi's Mitre" is a famous and much sought-after Western Pacific mitrid ranging from Japan to the Philippines. When initially discovered in Japan, it was thought to represent a recently extinct species as no live specimen was found. Many years later however, live specimens started to surface. In fact it is named after Mr. Shoichiro Hayashi, the first person to collect a fully mature specimen of this species alive and provided it for description. It used to be rare to very rare, and was made famous by inclusion in the classic book "Rare Shells of Taiwan" (1979) by T.C. Lan. Majority of specimens do actually come from Taiwan, although recently more specimens are surfacing from the Philippines. It has become more readily available in the recent years and is now perhaps best described as uncommon or moderately rare. A carnivorous and predatory gastropod feeding probably on sipunculids like most mitrids, it lives on soft bottoms of rather deep water around -100~300m. Typical shell length around 50mm, very large specimens may exceed 65mm. Though used to be placed in the genus Scabricola it is now generally accepted to be a member of Mitra and included in the subgenus Nebularia, considered by some to merit a full genus status.

Ficus investigatoris (Smith, 1894) <br />
FICIDAE<br />
-150~200m, In fisherman's net, Muttom, Kanyakumari District, Tamil Nadu, India, 2015/x, 130.0mm <br />
<br />
The "Bengal Fig" is a large and intricately sculptured ficid found exclusively in the Indian Ocean, ranging from Bay of Bengal to Mozambique; the type locality being "Off Ganjam coast, eastern India". For many years it was considered a rare shell as the main supply was by-catch from trawlers working off Somalia, but very recently fresh supplies have emerged from India and it has become much easier to obtain. In its natural habitat it is a locally common gastropod mostly seen on sandy to muddy bottoms of rather deep water around -100~400m, although occasionally it is found as shallow as -30m. Ficidae is considered to feed by swallowing small organisms with detritus and organic particles, though some claim they feed on echinoderms and polychaete remains have been detected in the digestive tracts of Ficus. The surface sculpture is characteristic and little-varied among individuals, although the shell width to height ratio varies considerably. Typical shell length around 100mm, very large specimens (as shown) are known to exceed 130mm. In "A Conchological Iconography: The family Ficidae" (2000), Varhaeghe & Poppe cited the authority of this species as "Smith, 1906", but this was due to a confusion between two references by the same author and it was actually described in 1894. The specific epithet refers to the H.M. Indian Marine Survey Steamer "Investigator" which collected the first specimens that became the basis of the original description.

Barnea dilatata (Souleyet, 1843) <br />
PHOLADIDAE<br />
-20~30m, Trawled in mud, West Phuket Island, Thailand, 1998/ii, 79.3mm <br />
<br />
The "Dilate Piddock" is a large burrowing pholadid with a rather wide distribution in the Indo-West Pacific, ranging from Japan to India to Australia. A common filter-feeding bivalve with a much larger body than the shell, it lives deeply buried in sand or mud in shallow water from intertidal down to about 20m deep. Its very long siphon (up to four times shell length), which it uses to feed, is considered a delicacy in some places. For example in Ariake Sea, Japan it is a famous local speciality and is widely harvested to be eaten either fresh or dried; although its numbers in that area appears to be diminishing in the recent years. The shell is very fragile and has one calcified accessory plate, the protoplax. The apophysis, spoon-like appendage serving as a point of attachment for the foot musculature, is very long and narrow. Typical shell length around 80mm, very large specimens may exceed 120mm.

Luria tessellata (Swainson, 1822) <br />
CYPRAEIDAE<br />
-5~10m, Dived, Oahu Island, Hawaii, USA, 32.2mm <br />
<br />
The "Checkerboard Cowrie" is a highly distinctive cypraeid with its four characteristic dark blotches on the dorsum. An exceedingly famous and much sought-after species, it is very variable in blotch development and is thus not easy to find a specimen with well-balanced 'checkerboard' pattern; it is also rather variable in callous development. An omnivorous gastropod, it lives under corals and rocks from rather shallow to moderately deep water ranging around -3~50m. Almost all specimens are from Hawaii where it is uncommon (live specimens becoming rarer recently) and it was once thought to be an endemic there. From the 1980s, however, a few have been taken live around Taiwan and more recently in the Philippines; its true range therefore appears to be quite wide. It appear to only occur in the deep water in the western Pacific and is extremely rare there; the name Luria lani (Raybaudi 1986) was given to the Taiwanese population but is currently regarded as a junior synonym. Typical shell length around 30mm, extremely large individuals are known to reach 55mm.

Calliostoma toshiharui Kosuge, 1997 <br />
CALLIOSTOMATIDAE<br />
-150m, By tangle nets, Aliguay Island, Zamboanga Peninsula, Mindanao, Philippines, 2003/viii, 44.4mm <br />
<br />
The "Toshiharu's Top Shell" is a large and spectacularly ornamented Western Pacific calliostomatid ranging from the Philippines to Borneo. It is characterised by two to three spine-bearing spiral cords just above the suture, although the development of spines vary among individuals. The whorls are strongly shouldered due to the spine-bearing cords being especially prominent and thus appear slightly concave. A rare species even in the usual dead collected condition, live taken specimens without significant damage (as shown) are very rare. Most likely a carnivorous grazer feeding on tissue of cnidarians like most calliostomatids, it inhabits rather deep water around -150~300m. Typical shell height around 35mm, extremely large specimens may exceed 50mm.

Tonna melanostoma (Jay, 1839) <br />
TONNIDAE<br />
-60~80m, In fishing net, Off Kakeromajima, Amami Islands, Kagoshima Prefecture, Japan, 2007/vi, 235.9mm <br />
<br />
With a unique dark aperture the "Black-mouthed Tun" is an unmistakable and extremely handsome tonnid ranging from southern Kagoshima Prefecture, Japan to New Zealand. It is not only the most coveted and sought-after tonnid species of all, but also a species of legendary fame and rarity among all shells. A very large tonnid with an average shell length around 220mm, extremely large specimens are known to exceed 300mm. Despite having a large size and being easily recognisable it is very rare across its rather wide range, especially adults displaying well the signature black mouth. Most specimens appear to originate from either southern Japan or around New Caledonia, although recently young specimens have been surfacing frequently from the Chinese coast. Young specimens lack the signature "black mouth" as that only develops as the snail matures, but the characteristic sculpture of alternating thick and thin spiral cords make them unmistakable still. The only species it may be mistaken with is its sister species Tonna hawaiiensis Vos, 2007 which is endemic to Hawaii and has been wrongly treated as the same species for many decades. Tonna hawaiiensis, however, is a much smaller species on average and never develops a fully black aperture to the extent of T. melanostoma even when mature. Like other tonnids it is a carnivorous and predatory gastropod inhabiting sandy to muddy bottoms and predominantly hunts holothurians (sea cucumbers), most likely nocturnally.

Cymbiola irvinae (E. A. Smith, 1909) <br />
VOLUTIDAE<br />
-120m, Trawled on sandy to muddy bottom, South of Mandurah, Western Australia, Australia, 78.3mm <br />
<br />
The "Irvin's Volute" is a solid volutid endemic to the western shoreline of Western Australia, Australia. A little-varied species in terms of patterning and form, but the extent of shoulder spine development is very variable from being completely smooth and spineless to having long and recurved spines. It is a rather rare and sought-after species that is usually dredged dead or crabbed, live-taken specimens are very rare. Although it closely resembles the much more common Cymbiola nivosa (Lamarck, 1804), that species has a much smaller protoconch and less dense shoulder spines (when present) which are always solid and not hollow like those of C. irvinae. A carnivorous and predatory gastropod feeding on other invertebrates, it inhabits sand or gravel bottoms of moderately deep water around -50~250m. Typical shell length around 100mm, extremely large examples are known to reach 130mm.

Perotrochus wareni Anseeuw, Puillandre, Utge & Bouchet, 2015 <br />
PLEUROTOMARIIDAE<br />
-350~450m, Dredged, Grand Passage, North of New Caledonia, 45.4mm <br />
<br />
The "Warén's Slit Shell" is a small pleurotomariid endemic to New Caledonia, characterised by a fine pustulose sculpture. For many years, it was considered to merely represent a 'pustulose form' of P. caledonicus Bouchet & Métivier, 1982 which occured allopatrically and shared with it similar size, colour, and shape. The type specimen of P. caledonicus, however, had smooth and unbeaded spiral cords; no clear intergrades between the two forms were known. Only very recently, a study using both morphological and molecular data finally revealed that the two in fact represent two distinct lineages and are separate species. The 'pustulose form' was therefore described anew, as Perotrochus wareni, shown here. Though the two species appear to occur allopatrically in New Caledonia, P. wareni is more common in the northern New Caledonia while P. caledonicus is predominantly found in the southern areas around Isle of Pines. They also differ slightly in depth preference, with P. wareni occuring mostly around 350m deep and P. caledonicus slightly deeper at around 400m. Furthermore, the range of P. wareni extends westwards to Lansdowne Plateau in the Coral Sea but the range of P. caledonicus does not appear to reach the Coral Sea at all. The population from Chesterfield Plateau in the Coral Sea, previously attributed to P. caledonicus, was revealed to be a further distinct species in the same study and was named P. pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015. It inhabits hard substrates and is a carnivorous grazing gastropod feeding on demosponges. Typical shell length around 40mm but extremely large specimens may exceed 70mm. Though it is locally somewhat common, high quality specimens are uncommon on the shell trade market.

Perotrochus caledonicus Bouchet & Métivier, 1982 <br />
PLEUROTOMARIIDAE<br />
-350~450m, Dredged, Southwest of the Isle of Pines, New Caledonia, 50.5mm <br />
<br />
The "New Caledonia Slit Shell" is a small, lustrous pleurotomariid endemic to New Caledonia as its name suggests. For many years, this species was thought to occur in two forms with distinct sculpture -- a 'smooth form' with uninterrupted spiral cords and a 'pustulose form' with the cords divided into many conspicuous beads. Although no obvious intergrades were known, the two were similar in size, colouration and shape as well as co-occuring in similar areas and were thus assumed to represent a single species. A recent study using both morphological and molecular data clearly revealed, however, that the two in fact represent two distinct lineages and are separate species. The 'smooth form', as shown here, corresponds to the nominal P. caledonicus and is more common in the southern New Caledonia, though the distribution range does extend northwards up to the Grand Passage area. The 'pustulose form' was newly described as Perotrochus wareni Anseeuw, Puillandre, Utge & Bouchet, 2015; it is more common in the northern New Caledonia but also occurs in the south, and the range extends westwards to Lansdowne Plateau in the Coral Sea. These two species differ slightly in depth preference, with P. caledonicus occuring mostly around 400m deep and P. wareni mostly around 350m deep. The population from Chesterfield Plateau in the Coral Sea, previously also attributed to P. caledonicus, was revealed to be a further distinct species and was named P. pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015. The name P. caledonicus therefore currently refers solely to the 'smooth form'. A carnivorous grazing gastropod, it lives on hard substrates and feeds on demosponges. Typical shell length around 40mm, extremely large specimens are known to exceed 65mm. Though it is locally not uncommon, high quality specimens are still uncommon in the international shell trade.

Bursa verrucosa (Sowerby I, 1825) <br />
BURSIDAE<br />
-25m, SCUBA dived, Raoul Island (Sunday Island), Kermadec Islands, New Zealand, 31.6mm <br />
<br />
With numerous black warts well-contrasted against a whitish-yellow background, the "Verrucose Frog Shell" is one of the most striking bursids of all. The shell form is little-varied, but the warts vary in strength among individuals, in many cases a series of warts are reduced to a simple 'dotted-line'. It has a much restricted distribution from southeast Australia to Lord Howe Island, Norfolk Islands, Kermadec Islands, and northern New Zealand. One of the rarest frog shells and specimens are much sought-after by collectors, especially those with large and well-formed warts. It inhabits sandy to muddy bottoms of shallow subtidal water around -10~40m deep, and is a carnivorous gastropod like other bursids, probably mainly feeding on polychaete worms. Typical shell length around 30mm, very large specimens may exceed 55mm. A monotypic genus Annaperenna Iredale, 1936 was once proposed for it, but is now regarded as a synonym of Bursa.

Mikadotrochus salmianus (Rolle, 1899) <br />
PLEUROTOMARIIDAE<br />
-250~300m, Trawled, Off Kashiwa Island, Kōchi Prefecture, Japan, 1983/v, 93.5mm <br />
<br />
The "Salmiana Slit Shell" is an elegant pleurotomariid with a blazing coluration and a characteristically tall spire, ranging from Honshu, Japan to Taiwan to Philippines. A much sought-after rarity, most specimens have generally come from Taiwan although recently Chinese fishermen have also trawled many (mostly poor) specimens from the East China Sea. It reaches the largest size in Tosa Bay, Japan where the shells are the thickest and with a rather pale colouration; the shells gradually thins down towards south with specimens from the Philippines being the lightest in build but with a dark colouration. Both Tosa Bay and Philippines specimens are still very scarce today, especially in large size, though in the East China Sea it is probably best described as uncommon. A carnivorous grazer feeding on sponges, it inhabits hard substrates of rather deep water around -100~400m. Typical shell length around 90mm, extremely large specimens are known to exceed 135mm. For many decades since its description it was confused with its congener Mikadotrochus beyrichii (Hilgendorf, 1877) due to the small quantity and poor quality of available specimens. As better specimens surfaced, however, its obvious differences with M. beyrichii quicky became apparent and it has become widely accepted as a valid species since the 1970s. A well-known synonym is Mikadotrochus schmalzi Shikama, 1961.

Tenagodus obtusus (Schumacher, 1817) <br />
SILIQUARIIDAE<br />
Almeria, Andalusia, Spain, 118.9mm <br />
<br />
Tenagodus obtusus is a curiously shaped slit-worm shell with the first few whorls coiled regularly but suddenly shifting to growing an uncoiled tube. It is mainly known from the Mediterranean Sea with specimens from Atlantic waters generally attributed to T. senegalensis (G. B. Sowerby II, 1876), although some authors claim that the two should be considered synonymous. Tenagodus senegalensis appear to have generally more tightly coiled earlier whorls, although they are quite variable indeed. It is an obligatory sponge commensal and spends the entire life inside the host sponge, in most cases Holoxea furtiva Topsent, 1892. More than one specimens is usually found together in a cluster within the sponge. Most of the shell is completely embedded in the sponge which provides shelter and protection, only the uncoiled tube extends out. It is found in intertidal and shallow subtidal waters down to about -50m, and is a filter feeding gastropod. There is a corneous operculum supported by a much reduced foot, which is heavily sculptured with opercular bristles, the form of which is an important taxonomic character in this family. It is very similar in general appearance to the Indo-West Pacific species T. ponderosus Mörch, 1861, 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. obtusus is smooth-sided without denticulation throughout the entire teleoconch. Typical shell length around 100mm, extremely large specimens may exceed 160mm. Although generally a common species, it is uncommon to find one in good condition on the shell trade market.

Aplustrum amplustre (Linnaeus, 1758)<br />
APLUSTRIDAE<br />
Dived, Nuku Hiva, Marquesas Islands, French Polynesia, 19.9mm <br />
<br />
The "Royal Paper Bubble" is a most lovely aplustrid shell-bearing opisthobranch widely distributed across the tropical Indo-West Pacific. A carnivorous and predatory gastropod mainly feeding on polychaete worms, it inhabits fine sandy bottoms of shallow waters less than 15m depth and is common throughout most of its range. Generally instantly recognisable by its two characteristic broad pink bands bordered by black lines, but the pattern is actually somewhat variable, especially the thickness of black lines. Specimens from the Marquesas Islands (shown) appear to differ from all other by having much darker colouration and much thicker black lines. Typical shell length around 15mm, extremely large specimens may exceed 25mm. On a side note -- Voskuil (1995) separated from this species Aplustrum exquisitum (Voskuil, 1995) which has one thick black band, instead of two black lines and a white band, between the two pink bands; and tip of the columellar being bent slightly towards the right instead of left when viewed at the aperture view with apex pointed upwards. Aplustrum exquisitum is supposed to be endemic to Marquesas and co-exist with A. amplustre there. However, when one views sufficient material, it appears that A. exquisitum is most likely merely a form of A. amplustre with an uncommon pattern, as a whole range of intermediates can be found in Marquesas.

Buccinum viridum Dall, 1889<br />
BUCCINIDAE<br />
-800m, Trawled, Off Astoria, Oregon, U.S.A., 43.5mm <br />
<br />
The "Turban Whelk" is a deep-water buccinid native to the northern Pacific, best known from the West coast of North America. Although generally an inhabitant of sandy to muddy bottoms of deep water around -700~2500m, it is also an important member of chemosynthetic ecosystems off off California and Oregon, USA, being commonly found in hydrothermal vents (e.g., Explorer Ridge), methane seeps, and on whale falls. It is a carnivorous gastropod but also scavenges when the opportunity arises. There are two forms, one with an obvious spiral cord on the shoulder and the other with a rounded shoulder. Though supposedly a common species, it is quite an uncommon species in the shell trade. It is the type species of subgenus Viridibuccinum. Typical shell length around 40mm, very large specimens may exceed 60mm. A similar species, Buccinum thermophilum Harasewych & Kantor, 2002 is known from the Endeavour Vent Field, Juan de Fuca Ridge, and differs from B. viridum by smaller, narrower, more higher spired shell and a much more ovate aperture. Furthermore, the spiral ridges in B. thermophilum is generally much sparser.

Provocator mirabilis (Finlay, 1926) <br />
VOLUTIDAE<br />
Dredged from deep water, New Zealand, 122.4mm <br />
<br />
The "Astonishing Volute" or the "Golden Volute" is an elegant deep water volute endemic to sub-Antarctic Pacific waters around New Zealand. It is a locally not uncommon predatory gastropod living on muddy bottoms and has a rather wide bathymetric range between approximately -200~1500m. Unlike other members of genus Provocator it has a rather thick shell and no columellar folds, and is thus often placed in its own genus Iredalina. The protoconch is usually glazed over and forms a posterior spike-like structure, which varies in length and is rarely preserved completely. Two forms seem to exist: a more common form with sloped spire and more stout shell; and a rarer form with stepped spire and elongated shell (shown). Colour uniform, varying from pale to rather dark orange; a scarce white form occurs off Auckland Islands. Adults have thickened lip and the average shell length is about 100mm, but giants exceeding 160mm (with long, well preserved spike) are known to exist.

Buccinum mizutanii Habe & Ito, 1970 <br />
BUCCINIDAE<br />
-80m, Dredged, Off Kuril Islands, 1991, 77.5mm <br />
<br />
The "Mizutani's Whelk" is a uniquely sculptured cold-water buccinid ranging from Hokkaido, Japan to the Sea of Okhotsk. Whorls carry two prominent, thick spiral cords on the body whorl an additional weaker one on the base. The first cord below the shoulder is usually the strongest and is characteristically nodulose, giving it an unmistakable strongly wavy appearance. It is most similar perhaps to B. nodocostum Tiba, 1984, which shares the nodulose spiral cord but differs by the cords being more numerous and much narrower as well as less prominent. Buccinum opisoplectum Dall, 1907 and B. glaciale f. inclitum Pilsbry, 1904 are also similar but likewise these species also have more numerous, much narrower spiral cords and are easily separable. It appears to be a very rare species in the shell trade market. A carnivorous and scavenging gastropod, it inhabits muddy bottoms of rather deep water around -100~500m. Typical shell length around 90mm, very large specimens may reach 120mm. It is named in honour of Mr. Shosan Mizutani, a fisherman based in Abashiri, Hokkaido who first discovered this species.

2016年の一貝目は今年の干支「申」にちなんで、サルアワビ！この仲間は軟体が猿の尻のように赤いことから名付けられました。<br />
<br />
2016 is upon us, and it is a year of Monkey. The genus Scelidotoma is known as "Monkey Abalone" (saru-awabi) in Japanese as their soft parts are red, just like the bottoms of monkeys. Here's one from Japan to celebrate the arrival of a Monkey year! <br />
<br />
Scelidotoma gigas (Martens, 1881)<br />
FISSURELLIDAE<br />
-20~25m, Coast of Yagi, Hirono-cho, Iwate Prefecture, Japan, 82.3mm, F++, 2014/vii<br />
<br />
The "Giant Tugali Limpet" is a very large fissurellid native to northwest Pacific, with a distribution ranging from northern Korea and Japan (north of Fukushima Prefecture) to Sakhalin. A rather uncommon algae-grazing herbivorous species, it inhabits hard rocky substrates of intertidal to shallow subtidal waters down to about -30m deep. Although the shell is not colourful, its soft parts are vivid and brightly coloured in orange to red and the foot is larger than the shell. A shallow notch in the anterior end of the shell proves that it is a slit limpet, but this feature is often very inconspicuous in gerontic specimens. Typical shell length around 70mm, very large specimens may exceed 95mm. It used to be placed in the genus Tugali (hence the common name), but is now moved to Scelidotoma. Although the external appearance is similar to abalones, its flesh is said to taste bitter and vile when raw and tasteless when cooked. It is one of the host species of the symbiotic scale worm (Polychaeta: Polynoidae) Arctonoe vittata (Grube, 1855), which lives in the pallial groove of the host. The host helps the worm move about and protects it from predators, the worm does not feed on the host and in return helps the host fight off predators such as sea stars by biting them.

Thermosipho desbruyeresi (Okutani & Ohta, 1993) f. nipponensis (Okutani & Fujiwara, 2000)<br />
BUCCINIDAE<br />
-1002m, Iheya North Hydrothermal Field, Okinawa Trough, Japan, 80.2mm <br />
<br />
Thermosipho desbruyeresi is a large buccinid endemic to deep-sea hydrothermal vent fields. It has a wide distribution across Japanese vent sites in Okinawa Trough and Izu-Ogasawara Arc (depth range -600~1400m) and extending more than 8000km to Mariana, North Fiji and Lau Basins (depth range -1750~2750m). The Japanese population was described as a separate subspecies, T. d. nipponensis (Okutani & Fujiwara, 2000), but was later synonymised with T. d. desbruyeresi by Kantor et al (2013). A carnivorous / scavenging species, it has rather low population density and only rarely encountered especially in Okinawa Trough but is much more numerous in other localities. It is usually found on rock surfaces as well as in association with Bathymodiolus mussels which they feed on. The apex is always corroded away by the acidic flow of hydrothermal fluid, although the extent varies by locality and the acidity in the individual's microhabitat. The periostracum is often overlaid with various sulfide deposits from the vents, the extremeness of its habitat is evident. By far the largest gastropod native to Okinawa Trough hot vents, the average shell length is 70~80mm but giants may reach 100mm. It was originally described in the genus Eosipho, then considered to be an Enigmaticolus for a short period of time before the new genus Thermosipho was erected.

Bullia othaeitensis (Bruguière, 1789) <br />
NASSARIIDAE<br />
Masirah Island, Oman, 49.1mm <br />
<br />
Bullia othaeitensis is a very handsome nassariid characterised by numerous equally spaced spiral ridges. Native to Eastern Arabia with most specimens originating from Oman, the actual range may extend as far as Karachi, Pakistan. Its name is very confusing as although it is an arabian species, the specific epithet means "from Othaeite" with Othaeite being an alternative spelling of "Otaheite", an old name for Tahiti, French Polynesia. This is due to a mistake in recognising the origin of the type material, which unfortunately was not too uncommon back in the days when the accurate provinance for many species remained unclear for decades. In fact, the entire genus Bullia is absent from the Western Pacific. It is perhaps better known by the name Bullia tahitense (Gmelin, 1791) which is a junior synonym, and that name also means "from Tahiti". The two authors may have received material from the same lot with the same mistaken locality labels, especially considering the short time difference between the two descriptions, though this is merely speculation. The specific epithet is often misspelt in various ways, such as "otaheitensis" or "othaeitense". It is a very rarely available speices, mostly absent from collections. Fresh specimens carry sparse orange-brown axial flammules, though these fade over time. A carnivorous and scavenging gastropod, it inhabits sandy bottoms of shallow waters down to about -15m. Typical shell length around 30mm, very large specimens as shown may exceed 45mm.

Harpa doris Röding, 1798 <br />
HARPIDAE<br />
-2.5m (-8 ft), Dived by local person, On clean brown sand, Off Dakar, Senegal, 65.6mm <br />
<br />
The "Rosy Harp" is a lovely harpid ranging from Senegal to Angola, and is the only recent Harpa species in the Atlantic Ocean. It is characterised by radial bands of rectangular, rosy red patches that makes it an especially beautiful harp shell. The extent of red patches vary greatly among individuals and the synonym H. rosea Lamarck, 1816 is often used as a form name by collectors and dealers for exceptionally reddish specimens. Two distinct forms are known, the nominal form from coastal mainland Africa (shown) has thin, lightly constructed and more slender shells; whereas the form from Ascension Island and Cape Verde Islands are much more robust and shorter. The island form was initially described as a separate species, H. robusta Röding, 1798, and although regarded as a synonym today many feel it is still worthy of a subspecific rank if not a full species. Like all Harpa species it is a carnivorous and predatory gastropod that mainly feeds on small crustaceans, and inhabit shallow sandy bottoms to -30m depth. Typical shell length for the nominal form around 60mm, very large specimens may exceed 80mm; the island form is generally smaller and averages at around 40mm, though the largest specimens may exceed 70mm. It used to be a rarity before around 1980s when the Atlantic shells were less readily available, today it is regarded as a common species and has become easily obtainable.

Cardiomya behringensis (Leche, 1883) <br />
CUSPIDARIIDAE<br />
-350m, In shrimp traps, Off Teuri Island, Hokkaido, Japan, 2000/xi, 38.1mm <br />
<br />
Cardiomya behringensis is a rather solid medium-sized cuspidariid ranging from Honshu, Japan (both Pacific and Japan Sea) to Sea of Okhotsk to as far north as Bering Sea. Being a cuspidariid it is a carnivorous and predatory bivalve which hunts small animals, mostly crustaceans such as copepods and ostracods, using the inhalent siphon's suction power. It inhabits muddy bottoms of deep water around -200~450m deep, and is always covered by a layer of mud on top of the periostracum in natural condition. A very rare species, it is a celebrated collector's item among those who collect cuspidariid clams and difficult to acquire in collectible condition. Typical shell length around 20mm, very large specimens such as the one depicted may reach and exceed even 40mm.

Cuspidaria trosaetes Dall, 1925 <br />
CUSPIDARIIDAE<br />
-350m, In shrimp traps, Off Teuri Island, Hokkaido, Japan, 2000/xi, 28.5mm <br />
<br />
Cuspidaria trosaetes is a delicate, medium-sized cuspidariid from the Japan Sea, ranging from Hyōgo Prefecture to Hokkaido, Japan (and maybe the Kuril Islands). Like other members of Cuspidaria, it is a truly carnivorous and predatory bivalve that actively hunts small crustaceans (such as copepods and ostracods) using its inhalent siphon and trapping them in the mantle cavity. It inhabits a rather wide bathymetric range of around -50~650m, and is usually found on soft bottoms. It is characterised by a short, compressed posterior rostrum and a well inflated oval shell. The shell itself is white, with a greenish-brown periostracum which is thin and semi-transparent at first but increasingly thickens and as a result becomes more opaque in later stages. A rare species, it is very difficult to obtain a live-taken specimen in good condition. Typical shell length around 30mm, very large specimens may exceed 40mm.

Maurea tigris (Gmelin, 1791)<br />
CALLIOSTOMATIDAE<br />
New Zealand, 1960s, 62.0mm <br />
<br />
Delicately painted with alternating chestnut and pale yellow stripes, the "Tiger Maurea" is a beautiful endemic calliostomatid of New Zealand. It is the largest extant calliostomatid known to date, with the largest specimens reaching an impressive shell height of over 100mm, although vast majority are smaller and average at around 60mm. The largest specimens originate from off Three Kings Islands. The surface sculpture is fairly consistent, although the spire form varies from narrow conical to broad conical. The early whorls are almost always characteristically narrow and differ in sculpture from later whorls. Fully mature specimens have the inside of the outer lip noticeably thickened. The colouration pattern can vary quite a bit, for example many from off the Chatham Islands lack discrete axial bands with more scattered pattern, which was named as a subspecies C. tigris chathamensis (Dell, 1950) but now considered to be a synonym. It is a carnivorous grazer feeding on thecate hydroids and occur on rocky substrates from very shallow intertidal waters down to rather deep water around -200m. It is usually placed in the subgenus Maurea, which many consider worthy of a full genus rank.

Neancistrolepis glabra Habe & Ito, 1973 <br />
BUCCINIDAE<br />
-550~560m, 44°09.9'N 144°33.0'E, By deep-water whelk pot, Off Abashiri, Hokkaido, Japan, 1996/vii, 126.8mm <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 deep water around -500~800m. A highly coveted species by collectors of Buccinidae, it is an extremely rare species on the international shell trade, especially adult specimens of decent quality. Even locally in Japan it is now quite a rarity, it was once only uncommon but now the supplies have effectively run dry. In fully adult specimens, the outer lip recurves slightly and characteristically flares out, extending anteriorly. The periostracum is often 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 110mm, very large specimens may exceed 140mm. It is one of only two currently recognised species in the genus Neancistrolepis, the other being N. beringianus (Dall, 1919).

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