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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.

Megasurcula carpenteriana (Gabb, 1865)<br /> PSEUDOMELATOMIDAE<br /> -30~33 m, Dived in soft sand, One mile (1.6 km) south of Marina Del Rey Harbour, California, U.S.A., 1999/xi, 72.7 mm <br /> <br /> The "Carpenter's Turrid" is a large pseudomelatomid snail characterised by a shell with regular shoulder knobs, a distinct subsutural ramp, and dense spiral lines, ranging from California, U.S.A. to Baja California, Mexico. A carnivorous and predatory gastropod feeding on other invertebrate animals, it inhabits sandy bottoms of moderate depths between -20~100 m and is a rather common species sometimes found in large colonies. Although many specimens have strong shoulder knobs all the way until the adult body whorl, this is variable and some specimens only have shoulder knobs on early whorls. The frequency of shoulder knobs also often decreases towards the later whorls. Typical shell length around 70 mm, extremely large specimens exceed 90 mm. Most closely related to the co-occurring congener Megasurcula stearnsiana (Raymond, 1904), which is easily distinguished from M. carpenteriana by the following characters: 1) Complete lack of knobs on the spire, 2) Weaker subsutural ramp than M. carpenteriana, 3) A smaller shell (typically does not exceed 50 mm in length), and 4) Darker, wider spiral banding. It was named in honour of the British malacologist Rev. Dr. Philip Pearsall Carpenter (1819-1877).
Umbilia armeniaca Verco, 1912<br /> CYPRAEIDAE<br /> -135~145 m, Trawled on soft bottom, Off Ceduna, Great Australian Bight, South Australia, Australia, 85.4 mm <br /> <br /> As its name suggests, the "Apricot-Coloured Cowrie" is a cypraeid with a spectacularly coloured, large shell endemic to southern Australia; and one of the most iconic species of the region. Ranging between Perth, Western Australia and Port Lincoln area, South Australia, it is currently divided into four subspecies. <br /> <br /> The nominal subspecies (shown) is distributed throughout the Great Australia Bight between around -40~200 m, with a typical shell length of 85 mm and the largest specimens exceed 120 mm. Once very rare in the 1900s, the nominal subspecies has since been collected in large numbers as trawl bycatches and is now moderately common. The form name f. southstralica has once been proposed for generally smaller, darker shells supposedly from the eastern part of the range and f. westralica for the lighter, larger ones from supposedly the western part, but now it has become clear that both co-occur throughout the Great Australian Bight and are not regional variations. The easternmost subspecies U. a. diprotodon Lorenz & Beals, 2012 is limited to moderate depths of -30~60 m in the Port Lincoln area, characterised by large shells (typical shell length 100 mm, largest around 120 mm), short extremities, hints of blue along the margins and extremities, fine and short columellar teeth. This subspecies has been known under the form name f. brunnea for a long time but never received a formally published name; the informally published name f. hypersaturata also points to the same population. This subspecies used to be common in the 1990s, but is now very rare due to unclear reasons. Immediately west of the Great Australia Bight is home to the subspecies U. a. clarksoni limited to around -30~60 m deep in the Esperance area. Characterised by light, elongate shells with reduced margins and extremities (typical shell length 90 mm, largest shells exceed 105 mm), this is the rarest subspecies and it is suspected that its true habitat has not been located. Finally, U. a. andreyi inhabits deeper waters around -100~250 m further to the west, up to around Perth. This is a subspecies with very heavy, smaller shells (typical shell length 75 mm, very large specimens exceed 85 mm) and coarser, longer columellar teeth; it used to be extremely rare but recently a considerable number have been collected using remotely operated vehicles near Albany. All subspecies live on sand and rubble bottoms, they are spongivorous grazers and are usually found in association with their food sponges. <br /> <br /> The dorsal pattern is greatly variable among individuals, and to a lesser extent the saturation of the colour; albinistic specimens are extremely rare but do exist. The three non-nominal subspecies have been named in honour of the extinct giant marsupial Diprotodon, the famed Australian collector and diver Peter Clarkson, and the Russian cowrie collector Andrey Kostin.
Spondylus clarksoni Lamprell, 1992<br /> SPONDYLIDAE<br /> -27 m, Dived on flat reef, Exmouth, Western Australia, Australia, 115.4 mm <br /> <br /> The "Clarkson's Thorny Oyster" is a captivating spondylid characterised by a shell with pinkish colouration, especially near the umbo, and raised spatulated spines. Endemic to the northern part of Western Australia, Australia, it lives permanently cemented to hard bottoms on reefs between about -10~50 m deep and is a filter-feeder like all spondylids. Although unlikely to be truly rare in its natural habitat, individuals are typically covered by sponges and it is only rarely found with the shell in good condition. A little-varied and easily recognisable taxon among Spondylus species, individuals only differ in shell shape (determined to a certain extent by the substrate shape) and spine development. Typical shell length around 110 mm, very large specimens may exceed 140 mm. <br /> <br /> Named in honour of the famed Australian diver Peter Clarkson, who was a commercial abalone diver but also one of the most prolific shell diver and collector, discovering many new species and previously unknown habitats. Clarkson tragically lost his life in February 2011 to a shark attack while diving near Port Lincoln, but he is remembered by his extensive contributions to the understanding of molluscan life in Australia and will remain an inspiration for collectors many generations to come.
Serratifusus virginiae Harasewych, 1991<br /> AUSTROSIPHONIDAE<br /> -350~550 m, Dredged, Of Isle of Pines, New Caledonia, 2002, 48.2 mm <br /> <br /> Endemic to waters around Isle of Pines, New Caledonia, Serratifusus virginiae is a typical representative of the unusual buccinoidean snail genus Serratifusus whose shell superficially resembles members of Columbariidae (Turbinelloidea), the pagoda snails, and was initially placed in that family. The protoconch characters hinted that it may have different affinities and some authors even placed it in Fasciolariidae, but until the description of S. virgineus in 1991 all known species including the type species, Serratifusus craspedotus (Tate, 1888), were fossils from Miocene which precluded the examination of its radula and anatomy. Finally, dissection of S. virgineus revealed radula and soft part features typical of Buccinidae, resulting in its transfer to that family. More recently, a systematic revision of Buccinoidea has redistributed genera originally assigned to Buccinidae into several families, with Serratifusus being moved to Austrosiphonidae. <br /> <br /> Inhabiting soft bottoms of moderately deep waters around -350~500 m, it is a rather rarely seen species due to its restricted distribution. The shell is somewhat variable with regards to spine development and curvature (can be directed either to the anterior or posterior), spire height, and curvature of the siphonal canal. Although the feeding ecology is not known, it is probably a carnivorous and predatory snail feeding on other invertebrate animals. Typical shell length around 40 mm, very large specimens may reach 55 mm. It differs from all known living species in the genus by its long, hollow spines, and a colour pattern that lacks clear spiral bands as is typical of other species. In fact, it is mroe similar to the extinct Miocene species S. craspedotus in terms of shell form and spine formation. It’s name honours Virginie Heros, curator of Mollusca at Muséum National d'Histoire Naturelle, Paris.
Otukaia kiheiziebisu (Otuka, 1939) <br /> CALLIOSTOMATIDAE<br /> -860 m, On the tube of the siboglinid worm Lamellibrachia columna Southward, 1991, 'Off Hatsushima' seep site (35°00.954'N 139°13.326'E), Sagami Bay, Japan, KM-ROV dive #150, R/V KAIMEI Cruise KM21-E02, 19.2 mm <br /> NSMT-Mo 79206 [National Museum of Nature and Science, Tsukuba, Japan]<br /> <br /> A striking shell ornamented with three to four pleating keels makes the unmistakable the "Kiheizi's Top" one of the most famous Japanese calliostomatids and a classic rarity. It is endemic to Japan with its range restricted to the Pacific side of southern Hokkaido to Honshu to Shikoku. 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. Although its feeding habits are not well known it is most likely a carnivorous grazer feeding on cnidarian and other sessile organisms. The specimen shown here was collected living on the tubeworm Lamellibrachia columna Southward, 1991, and appeared to be feeding on the hydroids which were growing on the tubes. This was not only its first record from a cold seep (a chemosynthesis-based ecosystem), but also the first record of a live specimen from Sagami Bay. Furthermore, this makes it just the second calliostomatid species known from a cold seep worldwide. It is most similar to the more southern sister species Otukaia ikukoae Sakurai, 1994 with five or more finely granulated keels instead of three to four smooth ones, which is distributed from off Shikoku south to Okinawa in Japan. Similarly, O. ikukoae has also been spotted living on the same Lamellibrachia columna tubeworms, but in a hydrothermal vent in Okinawa Trough.
Sagamilepeta sagamiensis (Kuroda & Habe in Kuroda, Habe & Oyama, 1971)<br /> LEPETIDAE<br /> -760 m, On plastic debris, KM-ROV dive #150, R/V KAIMEI Cruise KM21-E02, Off Misaki, Sagami Bay, 35°04.197'N 139°32.575'E, Japan, 10.5 mm<br /> NSMT-Mo 79213 [National Museum of Nature and Science, Tsukuba, Japan]<br /> <br /> Originally described based on materials in the collection of Japan's Emperor Showa dredged from Sagami Bay, the lepetid true limpet Sagamilepeta sagamiensis is, as its name suggests, apparently endemic to Sagami Bay. A grazer feeding on bacterial mats and organic deposit on rocks and other hard substrates, it has a known depth range between 180 and 905 m and typically occur on dead shells and gravels among muddy bottoms. Recently, it was also found to inhabit plastic debris, like the specimen depicted here. It is a rarely seen species due to the depth range it inhabits being rarely sampled in Sagami Bay. Shells of individuals from deeper part of its range exhibits coarser shell sculpture (shown), which is known to intergrade with shallow water populations with finer sculptures. Most specimens have shells covered by a layer of black deposits, although the underlying shell colour is dirty or yellowish white. Typical shell length around 10 mm, very large specimens exceed 15 mm. First described in the genus Lepeta based on shell only, later the Japanese malacologist Takashi Okutani proposed the genus Sagamilepeta for it based on radula features. Today it remains the only species assigned to Sagamilepeta.
Circomphalus hiraseanus (Kuroda, 1930)<br /> VENERIDAE<br /> -150~200 m, Trawled, East China Sea, 2019/iii, 19.2 mm <br /> <br /> Sharply upturned commarginal ribs characterises the shell of "Hirase's Venus", a venerid bivalve ranging from central Honshu to Izu-Ogasawara region in Japan and southwards throughout the East China Sea. A filter-feeding bivalve inhabiting sandy bottoms, it inhabits shallow to moderate depths between -20~200 m. The commarginal ribs give the shell a frilly appearance and it is considered one of the most distinctive and attractive among bivalves of this region, and has always been a highly sought-after classic species by collectors, especially in Japan. Once extremely rare, only in the recent decade it has become more obtainable through Chinese trawl ships operating in the East China Sea. Most specimens have considerable damage to the frilly concentric ribs, it is still difficult to obtain a high-quality specimen. The shell is little-varied, although specimens vary somewhat in the number and frequency of commarginal ribs. The shell colouration is typically white, but it may also carry some yellowish or pinkish hue. Typical shell length around 20 mm, very large specimens may exceed 25 mm. Originally described in the genus Callanaitis, it was later moved to Circomphalus. <br /> <br /> It has an elegant Japanese name, 'Yume-Hamaguri', literally meaning the 'Dream Clam'. The Japanese malacologist Tetsuaki Kira (1888-1965) named his remarkable Japanese shell club magazine (the 'Yumehamaguri'), which continued for 14 years and 100 volumes since its start in 1946, after this species. Despite being in a different genus, it bears great superficial resemblance to the much larger Australian "Wedding Cake Venus" Bassina disjecta (Perry, 1811), which is also acknowledged in the Japanese name of B. disjecta, 'Ijin-No-Yume-Hamaguri', literally meaning the 'Foreign Dream Clam'.
Africolaria thersites (Reeve, 1847)<br /> FASCIOLARIIDAE<br /> -250 m, Trawled, Agulhas Bank, South Africa, 81.3 mm <br /> <br /> One of the most peculiar fasciolariid snails with the shell bearing highly characteristic strongly raised auriculate (ear-like) axial ribs, Africolaria thersites is a species endemic to South Africa where most specimens have been trawled from the Agulhas Bank region. Originally described as a turbinellid by Lovell A. Reeve (1814-1865) based on a single holotype from the Admiral Sir Edward Belcher (1799-1877) collection, the locality was supposedly China. This species was then "lost" for over a Century, with no specimens resembling the holotype being collected in Asian waters. Finally in 1993 the South African malacologist Richard 'Dick' Kilburn (1942-2013) noted that the holotype is morphologically identical to juvenile specimens of a rare and previously unidentified fasciolariid from South Africa and the holotype must have been mislocalised, settling both its true distribution and familial assignment. Since Admiral Belcher also led dredge expeditions in South Africa, the holotype was probably accidentally mixed with other materials in his collection; several other such cases of locality confusion in specimens originating from the Belcher collection have been noted in the literature. Although a single specimen supposedly from Nacala Bay, Mozambique, Kilburn concluded that this is also likely a mislocalisation and that the species is most likely a South African endemic. <br /> <br /> Placed in Fasciolaria by Kilburn, it was later moved to Africolaria in 2012 when that genus was proposed for a number of fasciolariids endemic to South Africa, based on the uncrenulated outer lip whose inner surface lacks lirae. The auriculate axial ribbing in this species is unusual among Africolaria species too, making it impossible to confuse with other fasciolariid species. The raised ribs usually become weakened in later whorls, but this is very variable among individuals and some exhibit the ribs throughout (shown). A rarely seen species found on soft bottoms of moderately deep waters around 100~300 m depth, it is presumably a carnivorous and predatory snail like other fasciolariids. Typical shell length around 80 mm, very large specimens may exceed 120 mm.
Heterogen longispira (Smith, 1886) <br /> VIVIPARIDAE<br /> -5~15 m, On mud bottom, Lake Biwa, Near Okishima, Omihachiman City, Shiga Prefecture, Japan, 60.3 mm<br /> <br /> A large viviparid snail endemic to Lake Biwa, the largest freshwater lake in Japan, Heterogen longispira is morphologically distinctive among all Japanese viviparids with its tall spire and angular whorls with a deep suture. Inhabiting shallow depths between -2~30 m, it used to be common across the entire Lake Biwa until 1950s but the population in the (much smaller) southern basin have dwindled since 1960s; the population the larger northern basin is also decreasing in numbers and it is now overall a rare species listed as Near Threatened in the Japanese Red List. Though sparse records of this species exists outside Lake Biwa in Japan (e.g., Kyoto, Gifu Prefectures), these are considered to be results of either misidentification or introduced with freshwater fishes from Lake Biwa, none of the introductions are known to have led to established populations. As is common with large viviparids, it is considered to be a mixotrophic species combining algae grazing, detritus ingestion, and filter-feeding using the gill. It is viviparous and female snails brood juveniles inside the ovary. Large individuals often have the shell surface covered by a layer of mineral deposit. Typical shell length around 55 mm, very large specimens can exceed 70 mm. <br /> <br /> The genus Heterogen was originally established in 1921 for housing only this species, but recent genetic studies have shown that the more widespread species widely known as Cipangopaludina japonica (von Martens, 1861) is very closely related to H. longispira and should be moved to the same genus, as H. japonica. In fact, these two morphologically distinct species are apparently indistinguishable based on the mitochondrial COI gene but introgressive hybridisation has been cited as a possible factor and future studies with nuclear markers are needed to clarify whether they are truly two separate species.
Zoila orientalis Raybaudi, 1985 <br /> (ssp. Z. o. raybaudii Lorenz, 1992)<br /> -18~25 m, On red sponge, Backstairs Passage, <br /> Kangaroo Island, South Australia, Australia, 57.1 mm <br /> <br /> The "Eastern Margin Cowrie" is a member of the Australian endemic cypraeid genus Zoila, once considered to be a subspecies of the closely related Z. marginata (Gaskoin, 1849) but now accepted as a separate species on its own right. From other species in the Z. marginata complex, including Z. marginata itself and Z. ketyana (L. Raybaudi, 1978), Z. orientalis is distinguished by a combination of shell characters such as the strongly corrugated margin whose left side is rounded, blut anterior extremity, and a lack of collar-like projections above the extremities. The margin is typically less well-developed compared to Z. marginata or Z. ketyana, while the spire is more exposed. The dorsum ranges from white to ivory to pink, the dorsal pattern almost always consists of more or less evenly and sparsely distributed circular, brownish spots. <br /> <br /> Only found along the southern coast of South Australia, currently it is considered to comprise two subspecies. The more western, nominal subspecies ranges from Great Australian Bight to St. Vincent Gulf and inhabits moderately deep waters around -70~150 m, and is characterised by smaller (typical shell length 45 mm, very large specimens exceeding 55 mm), narrower shells with a taller spire. The eastern subspecies Z. o. raybaudii Lorenz, 1992 (shown) lives on red sponges in shallower waters around -10~40 m deep and ranges between Adelaide to Ceduna; it is characterised by larger shells (average shell length around 55 mm, very large specimens are known to exceed 65 mm) that are also much more inflated and humped than the nominal subspecies. At the time of discovery, the species was extremely rare with the few known examples all belonging to the deeper population; today the nominal subspecies from this population remains extremely rare, while the shallower subspecies Z. o. raybaudii is only uncommon. Like other Zoila it is a spongivorous grazer, and is typically found living on its food sponge. <br /> <br /> The species' original description was a short one in The Connoisseur of Seashells and did not provide detailed locality data of the slightly aberrant holotype, leading to years of confusion about which population it came from. The holotype was considered lost for many years, but in 2007 it was rediscovered in Felix Lorenz's collection and the collection data of -80 m confirmed it to be from the deeper population. This was shortly after the deeper population was given a different name, Z. gabensis Van Heesvelde & Deprez, 2007, which is now considered to be a junior synonym of Z. o. orientalis. Three form names (not valid according to the International Code of Zoological Nomenclature) have been proposed for the shallower population, including f. intermedians Lobetti, 1986, f. extrema Raybaudi, 1992, and f. meridionalis Raybaudi, 1993; these are all based on different examples of Z. o. raybaudii. The subspecies name of the shallower population, raybaudii, honours Luigi Raybaudi Massilia (1913-2003), an Italian conchologist and shell dealer who concentrated his efforts on cowries.
Lirapex felix Chen, Han, Copley & Zhou, 2021 <br /> PELTOSPIRIDAE<br /> Paratype (NSMT-Mo 79160): -2785 m, 'Tiamat' Chimney / DFF11 (37.7838°S, 49.6495°E), Longqi vent field, Southwest Indian Ridge, RRS James Cook expedition JC67, ROV Kiel6000 Dive 142, 2011/xi/29, 3.7 mm <br /> <br /> Known only from two individuals taken from a single chimney structure ('Tiamat' Chimney / DFF 11) in Longqi vent field on the Southwest Indian Ridge, Lirapex felix is a small peltospirid snail characterised by a depressed spire and a lack of coil loosening on the body whorl that occurs in other Lirapex species. The digestive tract is filled with dark mineral deposits among organic matter, indicating that it feeds by deposit feeding or grazing the chimney surface, like other Lirapex species. The shell is trochoid and carries weak but frequent axial ribs that vary in strength among individuals but are always evident near the shoulder and around the umbilicus. The holotype is 2.6 mm and the paratype is 3.7 mm in shell width, typical for the genus Lirapex which contains small peltospirid snails. <br /> <br /> On the same chimney, it co-occurs with four other peltospirid snails, including the congener L. politus Chen, Zhou, Wang & Copley, 2017, which were all collected in large numbers through considerable collection efforts at Longqi field through multiple research cruises. The fact that only two specimens of L. felix have been taken indicates that it is either a rare species or its microhabitat is obscure and has not been successfully sampled. The specific epithet 'felix' means 'lucky, happy or blessed' in Latin and was given in reference to the serendipitous discovery of the first specimen of this apparently rare species and the fortunate finding of the second specimen that allowed for a comprehensive description.
Columbarium subcontractum (Sowerby III, 1902)<br /> COLUMBARIIDAE<br /> -150 m, Trawled, KwaZulu-Natal, South Africa, 41.2 mm <br /> <br /> Only known from a small area around Durban off KwaZulu-Natal, South Africa, Columbarium subcontractum is a columbariid with a small yet elegant shell characterised by a very angulated, diamond-like shell shape -- due to the strongly sloped shoulder and a single, distinct, keel between suture lines. The shell is typically white and may carry some yellowish patches; there are fine spiral lirae throughout the entire shell surface, all of which are similar in strength. <br /> <br /> Originally described in genus Fusus (now Fusinus) as a fasciolariid, it was once moved to Latirus, also in Fasciolariidae, as a senior synonym of Latirus mosselensis Tomlin, 1932 (now Hemipolygona mosselensis (Tomlin, 1932)). Finally in 1973, the South African malacologist Richard 'Dick' N. Kilburn (1942-2013) identified several conchological features, such as the protoconch, showing that this name does not refer to Hemipolygona mosselensis (Tomlin, 1932) but in fact to a different species that should be placed in Columbarium. <br /> <br /> Presumably a predatory gastropod feeding on tube-dwelling polychaete worms like other columbariids, it is found in moderately deep waters around -150~400m. A rather rare species, despite the characteristic shell shape and the uniform strength of spiral lirae throughout the whorls make its identification relatively straight-forward, most specimens exchanged under this name on the shell market are misidentified and finding a real C. subcontractum can be a real challenge. Typical shell length around 45 mm, very large specimens may exceed 60 mm.
Casmaria unicolor (Pallary, 1926)<br /> CASSIDAE<br /> -10 m, Dived on sand, Red Sea, Egypt, 86.2 mm <br /> <br /> A cassid endemic to the Red Sea, the "Unicolor Bonnet" inhabits shallow water from the extreme low tide down to about 50 m deep and is typically found on sandy bottoms. A common carnivorous gastropod, it is a predator specialised in echinoderms, especially sea urchins. Like many other Casmaria species, it exhibits considerable variations in shell morphology in that 1) the shoulder ranges between completely smooth to highly nodulose (the early whorls are typically more nodulose), 2) height vs width ratio, related to shoulder morphology with the more nodulose specimens being wider in appearance, 3) colouration ranging from white to bluish to light brown. The shell size at maturation is also greatly different among individuals, "dwarf" mature specimens can be under 30 mm in shell length while very large specimens (like the one shown) may exceed even 85 mm; typical specimens tend to be around 45 mm. <br /> <br /> Though many Casmaria species are similarly variable in shell form and thus appear to be confusing at first, the number of brown blotches on the terminal varix in combination with the number and position of spines on the outer lip provide useful characters that reliably distinguish the different species. The combination of 11-12 blotches on the varix and 10-12 spines along almost the entire stretch of the outer lip in C. unicolor is unique among all currently recognised Casmaria species. Among them, C. unicolor is perhaps most similar to C. ponderosa (Gmelin, 1791) (East Africa to Hawaii) and Casmaria boblehmani Fedosov, Olivera, Watkins & Barkalova, 2014 (India to Hawaii) in overall shell morphology, but C. ponderosa has five major blotches plus two to three intermediate strokes with seven to nine spines on the anterior half of the outer lip and C. boblehmani exhibits nine to ten blotches of more or less equal size with 8-9 spines also concentrated on the anterior half of the outer lip.
Perotrochus amabilis (Bayer, 1963)<br /> PLEUROTOMARIIDAE<br /> -150 m, Dredged, Off Florida, U.S.A., 98.3 mm <br /> <br /> Ranging between Texas to southern Florida, U.S.A. along the northern Gulf of Mexico, the "Lovely Slit Shell" is a medium-sized pleurotomariid with strongly beaded whorls overlaid by brilliant brick-red flammules. Inhabiting rubble bottoms of moderately deep waters around 100~300 m depth, it is a grazing gastropod feeding mainly on sponges. Originally described based on a single specimen trawled by R/V Gerda in 226 m deep southeast off Sombrero Light, Florida, U.S.A., it has always been a rare species and remains scarcely seen in collection today. A number of specimens have come up around 1980s in dredgings by Riley and Donna Black, but since then virtually no fresh specimens have been collected in the recent years. The shell is rather thin and light for its size, specimens vary somewhat in the strength of beading and spire height. Typical shell diameter around 75 mm, extremely large specimens can exceed 90 mm and such geronic specimens (shown) often become taller than wide. <br /> <br /> It is most closely related to the congener Perotrochus maureri Harasewych & Askew, 1993 distributed more northernly between northern Florida and South Carolina, U.S.A; the emergence of Florida Ridge during Neogene has been cited as the event when these two species became isolated as separate evolutionary lineages. The two species apparently have slightly different adapations to water temperature, with P. maureri living below the 10°C thermocline and P. amabilis above it. They are in fact not difficult to differentiate, as P. maureri is much smaller (average diameter 45mm vs 70mm), has lower spire and fewer spiral cords, and is typically much darker in colouration with more frequent dark flammules. Furthermore, the early spire angle of P. amabilis is typically much steeper than in P. maureri, resulting in a sharply pointed apex. The much more southern, Brazilian, species Perotrochus atlanticus Rios & Matthews, 1968 is also rather similar, but can be differentiated by its heavier shell with a less steep spire and much finer sculpture.
Calliotectum tibiaeforme tibiaeforme (Kuroda, 1931) <br /> VOLUTIDAE<br /> -200~250 m, Trawled, Tosa Bay, Kochi Prefecture, Japan, 69.5 mm <br /> <br /> The "Tibia Volute" is a deep water volutid ranging widely in the western Pacific, known from localities such as Japan, Australia, New Caledonia, Philippines, and Indonesia. A carnivorous and predatory gastropod, it inhabits soft bottoms of rather deep waters around -100~900 m. It is an extremely variable species with populations from different localities exhibiting discrete shell morphology, leading them to once be all treated as separate species. The discovery of intermediate populations revealed that these are more likely variations within a single species, today the geographically disjunct populations are typically treated as subspecies, although some authors prefer to treat them as forms. <br /> <br /> The nominal subspecies C. t. tibiaeformis (shown) is only known from southern Japan, with the type locality being Kii Peninsula; it is easily distinguishiable from the other subspecies by its small adult size of around 60~95 mm shell length and a very short anterior siphonal canal. This nominal subspecies was once collected in some numbers by deep water trawlers in 1950s and 1960s, but have become rather scarce in the recent years. The common East China Sea population described as C. t. williamsorum (Rehder, 1972) has much larger and relativelly lighter shells compared to C. t. tibiaforme typically between 120~150 mm, and have more distinct siphonal canal. There are two forms or subspecies known from the Philippines, C. t. johnsoni (Bartsch, 1942) being common in the Central Philippines characterised by a very slender shell with purplish colour and C. t. barneli Bail, 2006 being rare and restricted to a small area off Balut Island with broad, brownish shells; both forms are similar in size to the East China Sea population. The uncommon northwestern Australian form is known as C. t. dupreyae (Emerson, 1985), characterised by very large shells ranging between 120~230 mm in length and a white shell. There are further unnamed forms or subspecies from many localities such as New Caledonia, Indonesia, and Western Australia that obscure the boundaries between subspecies and forms; their true relationships must await comprehensive sampling and analyses using both morphological and genetics. <br /> <br /> All subspecies can be distinguished from the morphologically most similar Calliotectum smithi (Bartsch, 1942) from the Philippines by the adpressed suture resulting in the whorls appearing to expand less rapidly, and the axial ribs with square cross-sections (compared to triangular in C. smithi). Shells of C. tibiaeforme also typically carry a dark spiral band just beneath the suture, which is entirely lacking in C. smithi.
Perotrochus deforgesi Métivier, 1990<br /> PLEUROTOMARIIDAE<br /> -520 m, Dredged, Western part of Chesterfield Plateau, Coral Sea, New Caledonia, 35.6 mm <br /> <br /> With an unmistakable depressed trochoid shell, the "de Forges' Slit Shell" is a small pleurotomariid endemic to the Chesterfield-Bellona Plateau, New Caledonia, in the Coral Sea. Found between 300~600 m deep on the slope, it is a spongivorous grazer as is typical for the family and is often collected with sponges in dredges. Although scientific collecting off Chesterfield and Bellona have yielded dozens of specimens indicating its presence in considerable numbers there, outside of public collections its isolated and restricted distribution means it is a very rare species on the shell trade market. A very remarkable aspect of its morphology is that it appears to lacks the operculum entirely post-settlement, the only case among all described living pleurotomariids. Although pleurotomariids are known to frequently lose the operculum when alive, it seems highly unlikely that this was the case for all live-collected individuals from research dredgings which also included juveniles. Typical shell diameter around 30 mm, extremely large specimens can approach 45 mm. Its species name honours the carcinologist Dr. Bertrand Richer de Forges who organised the research dredgings that led to its discovery. <br /> <br /> Among living pleurotomariids it is one of four species in the Perotrochus caledonicus Bouchet & Métivier, 1982 group which also includes the two recently described species P. wareni Anseeuw, Puillandre, Utge & Bouchet, 2015 (previously often referred to as the 'granulose form' of P. caledonicus) and P. pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015. The prominently beaded spiral cords of P. deforgesi is sufficient to distinguish it from P. caledonicus and P. pseudogranulosus, and the depressed shell form is very different from the classic trochoid shells of the other three species. In terms of distribution ranges, Perotrochus deforgesi and P. pseudogranulosus are endemic to the Chesterfield-Bellona Plateau where P. caledonicus is not present and P. wareni is rarely seen. The two latter species have their main distribution ranges between Ile des Pins and Grand Passage, closer to the main island Grande Terre.
Empressostrea kostini Huber & Lorenz, 2007 <br /> GRYPHAEIDAE<br /> -10~30 m, Taken by diver, Nocnocan Island, Bohol, Philippines, 2017/iii, 117.8 mm <br /> <br /> The largest member of the superfamily Ostreoidea (the 'oysters'), the graphaeid Empressostrea kostini typically grow to over 200 mm in shell length with large specimens exceeding even 500 mm. It is perhaps surprising how such a large bivalve living in shallow to moderate water depth of 20~100 m was only described in the 2000s, but this may be explained by its highly concealed habitat within submarine caves. Living permanently cemented to the walls inside the caves, it has been reported to feed by trapping particles using numerous mucous strings and is therefore a suspension-feeder. Originally discovered during a diving expedition to the Spratly Islands, South China Sea in 2006, it has since then been found in several other localities in the southern Pacific including Indonesia, Philippines, and Palau. <br /> <br /> Like many gryphaeids the shell shape is very variable depending on the substrate, but generally the outline is more or less circular. The white shell surface is sculptured with numerous delicate, sharp-edged layers of raised foliations which are most conspicuous in young specimens (shown) but are usually completely worn out during later growth. The hinge line is unusual in being completely straight without protrusions from the resilium. <br /> <br /> The genus Empressostrea is monotypic and was erected anew to house this species on the basis of the very large size and its atypical feeding mode using mucous strings. Whether these are sufficient to distinguish it from the closely related Neopycnodonte at a genus level has been debated and remains unsettled. Morphologically it is perhaps closest to Neopycnodonte zibrowii Gofas, Salas & Taviani, 2009 from the Azores Archipelago in the northeastern Atlantic which also has the straight hinge line, but the muscle scar of N. zibrowii is much closer to the hinge and the shell is often pigmented in that species. It is difficult to be confused with any Pacific ostreoid, however on the specimen shell trade market it is very commonly misidentified as other gryphaeids or even ostreids.
Babylonia feicheni Shikama, 1973 <br /> BABYLONIIDAE<br /> -10~25 m, Trawled by fishing boat, Off Nha Trang, Vietnam, 2018, 53.6 mm <br /> <br /> Characterised by a semi-oval shaped shell with inflated, convex whorls the "Fei-Chen's Babylonia" is a medium-sized babyloniid known only from Vietnam. Originally described from only the holotype shell which was supposedly collected during a trip to Taiwan, for over two decades this remained the only known specimen of the species. In late 1990s it was rediscovered in the form of a population from Vietnam with virtually identical shell characteristics, casting doubt to the origin of the holotype. Investigation revealed that the holotype was already lost by then, leading to a neotype being designated from this newly discovered population. Until today this species has not been found from anywhere else, and its limited distribution means it is still rather uncommon in collections. As such, despite the locality of the holotype was stated as "East and South China Seas" it appears to be absent from the East China Sea; the holotype was probably a specimen originating from Vietnam that appeared in the fish market of Taiwan, possibly as a result of Taiwanese fishing vessels operating in the South China Sea. <br /> <br /> The shell form is unique among babyloniids and there is often a series of knobs of variable strength on the umbilicus, making it difficult to be confused with other species. As with most other babyloniids, the shell colouration is very variable and can range from pure white to more typical specimens with reddish brown pattern over a yellowish shell. Typical shell length around 40 mm, very large specimens may reach 55 mm. <br /> <br /> The specific epithet "feicheni" was dedicated to Fei-Chen Cheng, wife of the Taiwanese collector Su-Shan Chiang. Unfortunately at the time of description the suffix "-i" (indicating the name is that of a man) was used instead of the appropriate "-ae" (indicating the name is that of a woman). This was later discussed as an issue in the literature but since no information on the etymology was presented in the description paper indicating that this was an inadvertent error (and there was no Corrigendum by the authors), it cannot be emended and the suffix must be retained.
Calliostoma springeri Clench & Turner, 1960<br /> CALLIOSTOMATIDAE<br /> -300 m, Dredged, Off Key West, Florida, U.S.A., 24.2 mm <br /> <br /> The "Springer's Top" is an attractively beaded and showy calliostomatid native to the Carribean region ranging from Florida, U.S.A. to the Gulf of Mexico and is a moderately rare species whose shell is much sought-after by collectors. It inhabits relatively deep water around -200~500m and is presumably a carnivorous grazer feeding on sponges or octocorals like most other deep-water calliostomatids. Somewhat variable in form especially according to age, small specimens usually have much stronger keels on their body whorl. The base typically carry golden brown spiral lines, but they are absent in some specimens. The shell surface is shiny and carries a golden iridescence. Typical shell diameter around 25 mm, very large specimens may exceed 30 mm. <br /> <br /> Though often treated as a subspecies or form of Calliostoma benedicti Dall, 1889, the holotype of C. benedicti is in fact quite different in having a much narrower umbilicus encircled by a strong spiral cord with large beads. The holotype of C. benedicti is smaller (17.5 mm shell diameter) than the average C. springeri. Most specimens traded on the market as C. benedicti are actually C. springeri; the true C. benedicti appears to be a very elusive species. It is within possiblity that the holotype of C. benedicti is an unusual specimen and actually belong the same species as C. springeri, but further investigation is needed to decide the true relationship between these two names.
Conus crocatus Lamarck, 1810<br /> CONIDAE<br /> -50 m, On drop-off, West side of Olango Island, Central Visayas, Philippines, 63.7 mm <br /> <br /> Aptly named for its eye-catching shell colouration, the "Saffron Cone" is a widely distributed conid in the Indo-West Pacific region, ranging from Japan to New Caledonia to Mozambique. A carnivorous and predatory snail feeding on other molluscs, it inhabits sand to rubble bottoms of shallow to moderate depths between low intertidal zone down to about -100 m deep. It used to be very rare until the late 20th Century, so much that it was selected by S. Peter Dance as one of his fifty "Rare Shells" (1969). After large populations were discovered in locations like the Philippines, it quickly became easy to obtain and is moderately common today. Nevertheless, vast majority of specimens have significant growth scars on the shell and large, perfect specimens are still scarce and much sought-after. <br /> <br /> Although easily recognisable, it is a relatively variable species in shell form with the spire being variable in height and the white tent-like pattern differing greatly among individuals. Typical shell length around 60 mm, extremely large specimens may reach 110 mm. Such giant specimens are best known from New Caledonia, where they were once given the subspecies name C. c. magister Doiteau, 1981, considered to be a junior synonym today. In other localities it rarely exceeds 80 mm in shell length; the recently described C. c. pseudomagister (Allary & T. Cossignani, 2016) refers to a large form from the Philippines -- although currently still treated as a subspecies it is likely merely a form. It is currently placed in the subgenus Darioconus, which many consider to be a full genus. Conus thailandis da Motta, 1978 was once considered a subspecies of C. crocatus, but is today treated as a separate species on its own right. The main differences from C. crocatus are the generally wider shells with larger, less frequent white triangular patterning, and a darker colouration.
Erronea fernandoi Cate, 1969<br /> CYPRAEIDAE<br /> -5~10 m, By local diver, Eastern Samar Island, Eastern Visayas, Philippines, 1998/viii, 24.0 mm <br /> <br /> The "Fernando's Cowrie" is a small and enigmatic cypraeid native to the western Pacific, with a distribution range from the Philippines to the Maluku Islands, Indonesia to Solomon Islands. Presumably an omnivorous grazer feeding on overgrowth of rocky substrates on which it lives, it inhabits shallow to moderate depths around -10~50 m, preferring areas with strong current and has been frequently found together with sponges and giant barnacles. <br /> <br /> Since its discovery it has always been a rare species, most specimens were collected in the 1990s when a considerable amount was collected by local divers around Samar Island, Philippines as by-catch of giant barnacles; this supply has then ceased and now fresh specimens have become extremely rare. Vast majority of specimens have been taken from the Philippines, records from other localities are mostly based on scattered finds of single specimens. Some variation is seen across individuals in terms of dorsal pattern and the development of callous on the sides. Typical shell length around 20 mm, very large specimens are known to approach 35 mm. The specific epithet honours Fernando G. Dayrit, a shell dealer based in Manila, the Philippines. Another cowrie named after Dayrit is Eclogavena dayritiana (Cate, 1963). <br /> <br /> It is often confused with congeners such as Erronea xanthodon (Gray in Sowerby I, 1832) (actually endemic to Australia), E. ovum (Gmelin, 1791) (southwestern Pacific extending into Indian Ocean), E. pallida (Gray, 1824) (distribution mostly in Indian Ocean but extending to Indonesia), but can be distinguished by a series of shell characters such as paler base, narrower aperture and more slender shell, as well as having a ribbed columella. There is ongoing debate regarding whether or not the name E. stohleri Cate & Schilder, 1968 is a senior synonym of E. fernandoi Cate, 1969 and should therefore have priority. Currently E. stohleri is thought to be a synonym of Purpuradusta gracilis (Gaskoin, 1849), but the holotype is a freakish shell which may in fact be a dwarf specimen conspecific with E. fernandoi.
Semicassis umbilicata (Pease, 1861)<br /> CASSIDAE<br /> -30 m, Dived, Haleiwa, Oahu, Hawaii, U.S.A., 70.3 mm <br /> <br /> Characterised by numerous deep spiral grooves across the shell surface, the "Hawaiian Bonnet" is a cassid endemic to Hawaiian Islands (including Midway Atoll). An uncommon species, it inhabits sand and rubble bottoms in moderate depths between -20~200 m, and is a carnivorous and predatory gastropod feeding on echinoderms. One of many renowned endemic and representative molluscs of Hawaii, it is a much sought-after collector's item. Specimens are typically collected in the shallower part of its bathymetric range by SCUBA diving and lobster traps in deeper waters, but most specimens collected are crabbed empty shells and live individuals (and therefore specimen shells with original operculum) are rarely seen. Colouration of the shell surface ranges between very light pink to dark pinkish grey, and is overlaid by variable amounts of diffused reddish brown blotches. The shell form is little-varied among individuals; the shell sculpture is distinctive among living cassids and makes it an instantly recognisable species. The number of varices, indicative of paucity in shell growth, is variable; many specimens do not develop any intermediate varices before the final adult lip while some exhibit several such varices. Typical shell length around 60 mm, very large specimens may approach 85 mm.
Chicomurex ritae Houart, 2013<br /> MURICIDAE<br /> -80~150 m, Trawled, On rubble close to reef, Off Surigao, Philippines, 36.5 mm <br /> <br /> With a restricted distribution range in the southern Phillpines roughly around Leyte, Mindanao, and Siargao Islands, Chicomurex ritae is a medium-sized member of the genus and until recently confused with the superficially similar Chicomurex laciniatus (Sowerby II, 1841). As C. laciniatus is widely distributed from South Africa to Fiji to Queensland, Australia, their ranges overlap in the southern Philippines. The two species have very different protoconchs, with C. ritae having a rounded pausispiral protoconch around 1.5-2 whorls while C. laciniatus has a conical multispiral protoconch of 2.5-3.0 whorls. As the protoconch of C. laciniatus ends with a sinusigera ridge and has a sharp abapical spiral keel all around (which are lacking in C. ritae), it is possible to identify the two species as long as a part of the protoconch is present. Generally speaking, the teleoconch whorls of C. ritae are stockier and combines a higher spire with a shorter anterior siphonal canal, but due to the extreme variability in C. laciniatus it is difficult to distinguish the two species with absolute certainty without looking at the protoconch. <br /> <br /> Though the feeding ecology of C. ritae is not known for sure, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals like other Chicomurex species. It inhabits moderate depths around -80~150 m, and is an uncommon species; it is quite difficult to obtain a specimen with the protoconch remaining and therefore separable from C. laciniatus with certainty. The shell colouration vary from orange to light brown, the varices on the adult body whorl are typicall overlaid with dark brown blotches. Typical shell length around 35 mm, very large specimens may reach 45 mm. <br /> <br /> The species name is dedicated to Rita, wife of the species' author Roland Houart -- an expert on Muricidae and a highly prolific writer who has contributed greatly to our understanding of muricid systematics and taxonomy.
Naquetia annandalei (Preston, 1910)<br /> MURICIDAE<br /> -110~150 m (-60~80 fms), By tangle net, Off Loac, Panglao Island, Bohol, Philippines, 76.1 mm <br /> <br /> Shell with delicate, webbed, wing-like varices and intricately latticed fine sculpture makes the "Annandale's Murex" an attractive species much sought-after by shell collectors. Initially discovered off Gobalpur in the Bay of Bengal, India by Thomas Nelson Annandale (1876-1924), a British zoologist focusing mainly on sponges who worked primarily in the Indian Museum in Calcutta and Zoological Survey of India; the shells were sent to and studied by the British malacologist Hugh Preston (1871-1945), who named it after Annandale. Morphologically identical specimens quickly emerged from other, more eastern localities such as Japan and the Philippines, and today we know its range extends to Marquesas Islands and even Queensland, Australia. <br /> <br /> There has been great debate and confusion regarding whether it is the same species (and therefore a junior synonym) of the similar Naquetia barclayi (Reeve, 1858) from the Western Indian Ocean, originally described from Mauritius and ranges southwards to South Africa. Most literature of the past couple of decades has treated N. annandalei as a junior synonym of N. barclayi, though some have cast doubts on the decision. Recently, by carefully examining shell sculpture of specimens including juveniles, a number of reliable morphological differences could be found, leading it to be finally brought out from synonym and rehabilitated as a full species. The protoconch of N. annandalei is smaller than that of N. barclayi (1.1-1.5 mm vs 2.1-3.0 mm), and the two species also exhibit fine but consistent differences in spiral sculpture. Furthermore, the shells of N. annandalei have narrower, longer anterior siphonal canals than N. barclayi. Although generally speaking the shells of N. annadalei are narrower and less shouldered than N. barclayi, which is generally cited as their primary difference, this feature is actually variable among both species and correct identification requires examination of finer details in shell sculpture. <br /> <br /> A carnivorous and predatory gastropod, N. annandalei inhabits hard bottoms of moderately deep water around -50~200m and feeds on other invertebrate animals. The colouration is extremely variable (likewise in N. barclayi), ranging from dark brown to bright yellow. Typical shell length around 85 mm, extremely large specimens have been found to exceed even 130 mm.
Zemiropsis pulchrelineata (Kilburn, 1973)<br /> BABYLONIIDAE <br /> -300 m, Trawled, Off Durban, KwaZulu-Natal, South Africa, 2003, 24.5 mm <br /> <br /> A slender shell with a lovely pattern consisting of equally spaced, yellowish to reddish brown spiral lines characterises Zemiropsis pulchrelineata, a small babyloniid ranging from South Africa (type locality: East of Durban) to Mozambique. Most specimens have been dredged or trawled in rather deep waters around -300~500 m, although it has also been taken ex pisce off Mozambique as shallow as -150~200 m. A rare species especially in fresh condition, with only a single live-taken specimen and a few fresh dead specimens formally reported in the literature, most known shells have been collected long after death with dull, grey shell surface. The lack of live specimens in dredges or trawls has been suggested as evidence that it lives among rocky or hard substrates, making collection with such tools difficult. Although the feeding ecology of this enigmatic species is unknown, it is probably a carnivorous scavenger like other babyloniids. A little-varied species in shell morphology, although the spacing between the spiral lines (and therefore the frequency) can vary among individuals. Typical shell length around 25 mm, extremely large specimens approach 35 mm. Its sister species Zemiropsis demertziae Fraussen & Rosado, 2013 was originally considered to be a form, but later deemed to be a separate species due to the two co-occurring side-by-side in the same habitat in both South Africa and Mozambique. The two species share the same distribution range but do differ in shell form, with Z. pulchrelineata having more slender shell with narrower sutural canal and narrower umbilicus. The colour pattern on the shell is similar between the two, although generally speaking Z. demertziae exhibit finer lines.
Vullietoliva foxi (Stingley, 1984)<br /> OLIVIDAE<br /> -15~18 m (-50~60 ft.), SCUBA dived on sand, Cocos Island, Costa Rica, 1992, 23.1 mm <br /> <br /> Characterised by splendid tent-like pattern most intensely concentrated on two broad spiral bands, the "Fox's Olive" is a medium-sized olivid best known from the remote Cocos Island about 550 km southwest off Costa Rica. Although long considered an endemic of Cocos Island, it has also been recorded on one occasion from Isla Montuosa, Gulf of Chiriquí just off mainland Panama. This record indicates a much wider distribution range for the species, although the identity of these Gulf of Chiriquí specimens does deserve further study. The fact that there has been no further records of it from mainland Panama since, despite being much more accessible than Cocos Island, indicates its occurrence there is extremely rare. A very scarcely seen species primarily due to the difficulty in accessing Cocos Island, which together with its attractive markings has made its shell a highly sought-after collector's item. Inhabiting sand and rubble bottoms of relatively shallow waters around -10~30 m, most specimens have been taken by divers. No study of feeding ecology is available for this rarely seen species, but it is presumably a predatory and carrion-feeding gastropod like other closely related olivids. Although the general shell form is consistent among individuals, the amount and intensity of the tent-like patterns are very variable. Extremely dark specimens have almost the entire shell surface covered by brown markings, although the distribution pattern of the markings concentrating on two spiral bands is usually still visible to some degree. Typical shell length around 25 mm, very large specimens are known to exceed 40 mm. Originally described in genus Oliva, it was named for Alfred C. Fox of La Belle, Florida, U.S.A. who first discovered it during dredging and diving in Cocos Island with his wife Eva Fox. It was later moved to the genus Vullietoliva when it was erected in 2017 by Edward J. Petuch and David P. Berschauer.
Offadesma angasi (Crosse & Fischer, 1864)<br /> PERIPLOMATIDAE<br /> -50 m, Trawled, Off New Zealand, 62.5 mm <br /> <br /> The "Angas' Lantern Shell" is a large anomalodesmatan bivalve in the family Periplomatidae, ranging from southern Australia to New Zealand. An infaunal filter-feeding species, it lives buried in soft or sandy mud to about 10 cm deep (adults) and is found in sheltered environments from the lowest intertidal down to subtidal waters around 20 m deep. When buried its normal posture is with the (less inflated) left valve down, and two siphons extending up to the surface at about 2.5 cm apart from each other (in adults). As reported for other periplomatids, it is a poor burrower and adults are apparently unable to reburrow when dug out from the mud. Although relatively wide-ranging, it is an uncommon species that appear to have an intrinsically low population density, as has also been suggested for many other anomalodesmatan bivalves. The shell is aragonistic and very brittle, the overall shape is little-varied but the proportion and length of the posterior beak do differ somewhat among individuals. A transverse crack is present near the umbo, a feature typical of Periplomatidae (and also Laternulidae); the ligament is attached to large, spoon-like chondrophores. Typical shell length around 80 mm, very large specimens are known to exceed 100 mm. It is named in honour of the British naturalist and painter George French Angas (1822-1886) who made notable contributions to malacology in Australia. <br /> <br /> Among living bivalves it can only be confused with one species, its only extant congener Offadesma nakamigawai Kuroda & Horikoshi, 1952 described from Japan. Although the original description of O. nakamigawai quotes larger size and a more inflated shell as key features separating it from O. angasi, the holotype of O. nakamigawai is only 74 mm in shell length which is smaller than the typical size of O. angasi. The inflation of valves is also similar among the two species when examining a larger series of O. angasi. Although the holotype of O. nakamigawai has a more clearly constricted posterior beak than typical for O. angasi, other specimens from Japan attributed to O. nakamigawai often lack this feature. The distinctiveness between these two species are therefore not entirely clear, and it is possible that they represent the same species with a disjunct (known) distribution. Unfortunately O. nakamigawai is an extremely rare species known from only a few specimens, which makes in-depth evaluation of its validity difficult. For a long time no Offadesma specimens have been found in the vast area betwee Japan and Australia, but the recent finding of a single specimen in the Philippines (attributed to O. nakamigawai) indicate that they are present, and it is hoped more individuals may be found in the future to enable further comparisons with both O. nakamigawai and O. angasi.
Sultana labeo (Broderip, 1828)<br /> ORTHALICIDAE<br /> At high altitude, Taken on tree, Chachapoyas, Amazonas, Peru, 72.7 mm <br /> <br /> The aptly-named "Blubber-lipped Bulimulus" is, as its name suggests, characterised by a strongly thickened and often pitted lip that is almost black in colour when fresh and gradually fading to reddish. Endemic to a small area around Chachapoyas, northern Peru, it is restricted to isolated and inaccessible forests in tall mountain ranges over 2300 m above sea level. The first specimen known in the West was collected by Henry Lister Maw, a British naval lieutenant who travelled across northern Peru from 1827-1828 in an expedition down the Amazon River. Maw collected multiple specimens in Taulia, a town east of Chachapoyas, and had seen many more, but in the end only a single shell reached Europe. This specimen was studied by Broderip who described it, and then deposited in the Zoological Society of London. By late 1950s it has, however, mysteriously dissapeared from the collections and is now considered lost. Although it was highly sought-after among conchologists, very few specimens surfaced after that due to the difficulty in accessing its isolated habitat, both physically and politically. As such, it was considered to be one of the rarest landsnails for decades, despite being clear from early reports that it is common in its local habitat and even used as food by locals. Fortunately, supply of landsnails from northern Peru has surged in the recent few years, and at last this species has become available in some quantity along with other Peruvian orthalicids. Large specimens with well-formed lips are still rather difficult to secure, however. A herbivorous orthalicid landsnail living on and under trees, it feeds on lichens, algae, and various plant matter. Specimens vary little in the overall shell form, but do vary in the amount of spiral patterning and the development of the outer lip (thickness and amount of pitting), apparently different local populations tend to have varying levels of lip development. Typical shell length around 70 mm, very large specimens can exceed 90 mm. It was originally placed in genus Bulinus, today it is often offered under the genus Porphyrobaphe. Within the currently accepted placement in genus Sultana, it is placed in subgenus Metorthalicus.
Favartia hidalgoi (Crosse, 1869)<br /> MURICIDAE<br /> -250 m, Off Saint-François, Pointe-à-Pitre, Guadeloupe, 2018, 32.9 mm <br /> <br /> The profusedly frondose shell sculpture makes the "Hidalgo's Murex" an iconic species among Caribbean muricids. Ranging between North Carolina, U.S.A. and Brazil with the type locality being in Guadeloupe, it lives in moderate depths around -100~500 m and is rather rare. A highly sought-after collector's item, the most significant supply perhaps came from the famed Riley Black's dredgings in the Gulf of Mexico in the 1960s, which brought up numerous specimens off Florida. Typically the fragile shells come up with missing varices and often carry black staining, making complete specimens very difficult to obtain. Generally a little-varied species in terms of shell form, although the colouration may vary from pale to dark purplish brown. In most specimens the highly webbed varices and the scabrous sculpture across the entire shell surface are worn, giving a slightly different impression. Typical shell length around 30 mm, very large specimens are known to exceed 40 mm. It was named after Joaquín González-Hidalgo Rodríguez (1839-1923), a Spanish malacologist at the Royal Academy of Exact, Physical and Natural Sciences in Madrid. It is the type species of genus Murexiella Clench & Pérez Farfante, 1945, which is now considered to be a junior synonym of Favartia Jousseaume, 1880 -- although many still use Murexiella as a subgenus.
Maurea delli (McLean & Andrade, 1982) <br /> CALLIOSTOMATIDAE<br /> -400 m, Trawled by lobster fisherman, Off Quintero, Valparaiso, Chile, 1995, 27.2 mm <br /> <br /> With a pearly, iridescent shell strikingly sculptured by smooth spiral keels, the "Dell's Top" is a medium-sized calliostomatid endemic to Chile. A carnivorous grazer feeding on octocorals and sponges like many other deep water calliostomatids, it inhabits rather deep waters around -200~400 m deep. A moderately rare species, it is generally little-varied in terms of shell morphology. The spiral keels are completely smooth on the adult body whorl, but start off as a series of beads on the early whorls. Typical shell length around 25 mm, extremely large specimens may approach 35 mm. Originally described in genus Calliostoma and subgenus Otukaia typified by the Japanese species Otukaia kiheiziebisu (Otuka, 1939) which shares with it the feature of strong keels on a pearly-white shell, it was tentatively moved to genus Maurea as a part of Bruce Marshall's recent revision of deep-water calliostomatids in 2016. The argument was that it and other similar southern species such as the South American M. chilena (Rehder, 1971) as well as the western subantarctic M. eltanini Dell, 1990 possessed radula with fewer lateral teeth than O. kiheiziebisu (4–7 pairs versus 9 pairs), a characteristic shared with other Maurea species. Marshall interpreted that the similarity in shell morphology is more likely to be convergent than radular characteristics, and therefore moved these three species to Maurea. Nevertheless, these species are rather different in shell morphology from other Maurea species and future research will likely lead to further updates in their genus assignment. Maurea delli is most similar to M. eltanini in shell morphology, but in M. eltanini the first spiral keel is positioned further away from the suture, the keels on body whorl have prominent beading still visible, and that the base is covered by regular, crisp, spiral lines (which becomes obsolete in most parts in M. delli). Maurea delli was named in honour of the eminent New Zealand malacologist Richard Kenneth Dell (1920-2002).
Allonautilus perforatus (Conrad, 1847)<br /> NAUTILIDAE<br /> Trawled, Off Ambon Island, Maluku Islands, Indonesia, 160.5 mm <br /> <br /> The "Bali Nautilus", sometimes also called the "Indonesian Nautilus", is one of only two nautilid species in the genus Allonautilus characterised by shells with large umbilicus and a thick, fuzzy periostracum. A very understudied species apparently restricted to Indonesian waters, in the past most known specimens have originated from around Bali; although recently it has surfaced from a range of localities between Madura Island and in the Banda Sea off the Maluku Islands (most recent specimens have originated around here). <br /> <br /> Unlike its sister species Allonautilus scrobiculatus (Lightfoot, 1786) from Papua New Guinea and Solomon Islands which has been sighted and caught alive by scientists (although only a handful of times), there is no formal record of live A. perforatus and the animal has not been available for study. Though sometimes dubbed the 'rarest living nautilus', a considerable number of its shells have actually appeared on the shell trade in the past years. At least the majority of these are, however, supposedly drift shells, and no definitively live-taken material has been reported. As such, nothing is known about its ecology -- although it is most likely a predatory and scavenging carnivorous cephalopod inhabiting moderately deep waters around -100~600 m like other living nautilids. Until recently it was not known if it possesses a thick periostracum like A. scrobiculatus, but the surfacing of fresh-looking, supposedly trawled, materials with nearly complete periostracum shows that it indeed does. These specimens may have even been live-taken, raising hopes that the animal may become available for study in the near future. <br /> <br /> Its most distinct known morphological feature is the series of strong undulating radial ribs on both flanks of its shell, such strong radial sculpture is unknown from any other living nautilids, though many extinct nautiloids possessed similar ornamentation. This feature distinguishes it from A. scrobiculatus, which lacks these radial ribs and instead possess numerous zigzagging spiral lirae. These cross with fine radial growth lines to form a finely reticulate sculpture that is missing in A. perforatus. Despite these morphological differences, many remain doubtful if A. perforatus is truly a separate species from A. scrobiculatus. In the literature some have treated it as subspecies of A. scrobiculatus, and some merely as a local form. Resolving the status of A. perforatus conclusively requires obtaining live animals to compare the anatomical and genetic differences with A. scrobiculatus in the future. The genus Allonautilus is considered to differ from Nautilus in having a wide umbilicus, quadrate whorl cross-sections, and fuzzy periostracum, but also some anatomical features such as larger and more randomised papillae on the hood and smaller gills. These are currently only based on A. scrobiculatus and it would be of interest to see if similar anatomical features are shared by A. perforatus. <br /> <br /> The name Allonautilus perforatus (Conrad, 1847) should not be confused with Nautilus perforatus Willey, 1896, which is a junior synonym of Nautilus pompilius Linnaeus, 1758 based on a freak specimen with a narrow open umbilicus. Since 2017 all nautilids, including A. perforatus, are listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), thus curbing the international trade of nautiluses globally.
Allonautilus scrobiculatus (Lightfoot, 1786)<br /> NAUTILIDAE<br /> Off Ndrova Island, Admiralty Islands, Manus Province, Papua New Guinea, 172.2 mm<br /> <br /> With a large umbilicus and a thick, hairy periostracal layer, the "Fuzzy Nautilus" is a member of the enigmatic living nautilid genus Allonautilus. "Fuzzy" refers to the thick periostracal layer, which is golden-brown in colour and has also inspired other common names such as "Crusty Nautilus" and "Golden Nautilus". With a typical shell diameter of around 170 mm, very large specimens may exceed 200 mm and females are larger than males. Best known from Bismark Sea in Papua New Guinea, its range extends eastwards to the Solomon Islands. A predatory and scavenging carnivorous cephalopod, it inhabits rather deep waters around -150~400 m and is much rarer than the Chambered Nautilus, Nautilus pompilius Linnaeus, 1758, with which it co-occurs with. Live Allonautilus scrobiculatus has only been seen a handful of times by scientists, most notably in 1984 off Manus, Papua New Guinea which led to the descriptions of its anatomy. In 2015, a live individual was found off Mait Island, Papua New Guinea and made news headlines under the title "This Fuzzy, Golden nautilus hasn't been seen in over 30 years". More recently, it was found alive in Solomon Islands in 2019, where previously only drift shells have been collected. <br /> <br /> The species name 'scrobiculatus' refers to its characteristic scrobiculate shell sculpture comprising strong, zigzagging, spiral lirae crossed with weaker radial growth lines, resulting in a finely reticulate surface. This distinguishes it from the only other Allonautilus species, A. perforatus (Conrad, 1847) whose shell almost completely lacks the spiral lirae and instead develops rather strong, undulating radial ribs on the flanks of both sides. The presence of strong radial ribs in A. perforatus is unique among living nautilids, although it is a dominant feature in many fossil nautiloids. The two species are geographically segregated, with A. perforatus only known from Indonesia, mostly off Bali. Despite the shells of A. perforatus being much more commonly seen in the shell trade (often fresh, apparently live-taken ones) than A. scrobiculatus in the recent years, A. perforatus supposedly has never been seen alive and is often dubbed the 'rarest living nautilus'. Currently not all scientists accept A. perforatus as a separate species, some consider it to be a subspecies of A. scrobiculatus and some considers it simply a regional form. To resolve the status of A. perforatus conclusively requires obtaining live animals to compare the anatomical and genetic differences with A. scrobiculatus. <br /> <br /> The genus Allonautilus is considered to differ from Nautilus in having a wide umbilicus, quadrate whorl cross-sections, and fuzzy periostracum, but also some anatomical features such as larger and more randomised papillae on the hood and smaller gills. These are currently only based on A. scrobiculatus and it would be interesting to see if similar anatomical features are shared by A. perforatus. Since 2017 all nautilids including A. scrobiculatus are listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), curbing the international trade of nautiluses globally.
Bractechlamys langfordi (Dall, Bartsch & Rehder, 1938)<br /> PECTINIDAE<br /> -30~35 m, Taken under coral rubble, Off Diamond Head, Oahu, Hawaii, U.S.A., 1995, 26.7 mm <br /> <br /> The "Langford's Scallop", more famously known by the name "Sunrise Shell", is a small pectinid with brightly coloured valves endemic to the Hawaiian Islands. The left (upper) valve is more intense in colouration, usually dark orange to red, compared to the typically yellow to light orange right valve. Both valves are red on the inside with a yellow-orange fringe, again the left valve has slightly richer pigmentation. This attractive colouration has made them a popular and coveted material for jewelry production in Hawaii, and it is said to have been of cultural importance in the history of native Hawaiians, being a symbol of power and status. A filter-feeding bivalve living on sand and rubble bottoms, it lives in moderately depths around -20~50 m. Although live specimens are quite uncommon, worn single valves are often washed ashore and it is these valves that are commonly used for jewelry production. A relatively little-varied species, different individuals do display varying amount of white freckles on the valves and somewhat variable degrees of development of the knobs on the primary radial ribs. Typical shell length around 25 mm, very large specimens occasionally exceed 35 mm. For some years it was treated as a junior synonym of Bractechlamys nodulifera (Sowerby II, 1842), a species now considered to be restricted to Indian Ocean. Compared to B. nodulifera, B. langfordi is much more convex and appears more inflated. The colouration of B. nodulifera is much more variable than B. langfordi which is almost always orange-red.
Glabella mirabilis (Adams, 1869) <br /> MARGINELLIDAE<br /> -100 m, Trawled by commercial fishing vessel, Off Ras Hafun, Somalia, 2017, 29.2 mm <br /> <br /> With a shell carrying mesmerising patterns, the aptly-named "Wonder Marginella" is an eye-catching marginellid native to the western Indian Ocean. Vast majority of specimens have been trawled off Somalia, although its distribution range is actually wider, being found from the Gulf of Aden southwards with some records as far south as Madagascar. The holotype (currently in National Museum Wales) was from the collection of Sir David William Barclay (1804-1888), although most of the Barclay specimens originate from Mauritius where he resided, the locality of his G. mirabilis is listed as unknown. An uncommon species living in moderate depths around -50~200 m, its feeding ecology is not known but is supposedly a carnivorous gastropod like other marginellids and probably a predator of other invertebrate animals. Although the shell form is rather consistent among individuals, the shell colouration and pattern are very variable, especially in the development of the dark, cloud-like patterning. Typical shell length around 25 mm, extremely large specimens may reach 45 mm. It is often confused with the closely related (and more common) congener Glabella obtusa (Sowerby II, 1846) found from the Red Sea to Somalia. The main differences between the two species are that G. mirabilis has less closely spaced and less raised axial ribs, usually with much more prominent dark, diffused pattern, and the protoconch is more flattened (and not protruding and rounded like in G. obtusa). The shell of Glabella obtusa is also typically slightly smaller (average shell length around 20 mm) and more slender.
Austrotrophon cerrosensis (Dall, 1891)<br /> MURICIDAE<br /> -120 m, Trawled, Off Cedros Island, Baja California, Mexico, 1979, 42.4 mm <br /> <br /> Characterised by a shell with raised blade-like varices crossed by numerous low spiral ridges, the "Cerros Trophon" is a eastern Pacific muricid ranging between the southern California, U.S.A. and Cedros Island, Baja California, Mexico. A carnivorous and predatory gastropod, it inhabits moderately deep waters between -40~150 m. The colouration may vary from yellowish to light brown, and some specimens carry a pattern of alternating lighter and darker spiral banding. Although previously considered uncommon up until around the 1990s, fresh supplies have dwindled in the recent years, making it a very rare species to find. Typical shell length around 45 mm, very large specimens may exceed 60 mm. It is most closely related to Austrotrophon catalinensis (Oldroyd, 1927) which used to be considered as its subspecies, but the two overlap in geographic range and is today considered two distinct species. Compared to A. catalinensis, A. cerrosensis has less developed 'blades' on the varices with much shorter shoulder spines, more numerous varices per whorl (typically over 8 in adults vs. typically 7 in A. catalinensis), and much more pronounced spiral cording. The colour form with spiral banding is not seen in A. catalinensis which also reaches a larger size (typical shell length around 70 mm). Another species it may be confused with is Zacatrophon skoglundae Houart, 2010, also from the same geographic region. Zacatrophon skoglundae has a more excavated, deeply impressed suture and more posteriorly curved, flattened shoulder spines, that distinguishes it from Austrotrophon species.
Amygdalum peasei (Newcomb, 1870)<br /> MYTILIDAE<br /> -50~70 m, Dredged, East off Awase, Okinawa Island, Okinawa, Japan, 21.2 mm <br /> <br /> A finely reticulate pattern of brown lines in the posterior portion of the shell surface characterises the "Pease's Mussel", a small and beautiful mytilid with a very wide distribution range. Originally described from a single specimen dredged in about 22 m (12 fathoms) depth off Honolulu of Oahu, Hawaii, U.S.A., specimens with apparently identical shell morphology (and therefore presumed to be the same species) has later been discovered in many locations across the Indo-Pacific such as New South Wales in Australia, Japan, South China Sea, and even off Madagascar. The name Amygdalum plumeum Kuroda & Habe in Kuroda et al., 1971 was proposed in the famous book "The Sea Shells of Sagami Bay, Collected By His Majesty The Emperor of Japan" for a population in central Japan, but this is currently considered to be a junior synonym of A. peasei. Found in soft bottoms between moderate depths of around 20~120 m deep, it is considered to be a filter-feeding bivalve like most mytilids. The genus Amygdalum is known to build 'nests' made from byssus in cohesive mud, and A. peasei is no exception. Members of this genus also use haemoglobin as the oxygen carrier, resulting in a reddish pink colour of the soft parts, considered to be an adaptation to living in hypoxic mud. Once extremely rare and only known from a handful of specimens from various localities, more specimens have surfaced recently -- although it is still rather scarce. Typical shell length around 20 mm, very large specimens may reach 30 mm. Its Japanese name ("Wamei") is "Maboroshi-Gai", literally meaning "the Mythical Shell", due to its rarity in the early days. Morphologically it is most similar to Amygdalum americanum Soot-Ryen, 1955 from the Pacific coast of Americas, it is most easily distinguished by having a more posterior umbo than A. americanum and also a more diffused reticulate pattern.
Calliotectum smithi (Bartsch, 1942)<br /> VOLUTIDAE<br /> By tangle net from deep water, Balut Island, Mindanao, Philippines, 172.7 mm <br /> <br /> The "Smith's Deep-sea Volute" is a moderately large volutid, characterised by a shell with an impressed suture and deep, frequent axial ribs on the early whorls of the teleoconch. It has a restricted distribution, being an endemic species of the Philippines and with live specimens only recovered around -300~600 m deep (dead shells have been found in over 800 m deep). The holotype was trawled by the U.S. Fisheries vessel R/V Albatross off Balicasag Island, and is currently in the Smithsonian National Museum of Natural History. Inhabiting mud bottoms, it is considered to be a predatory gastropod like other volutids. For about 50 years since its formal description it remained extremely rare, although from the mid-1990s deep-water tangle nets began to yield some specimens. Today it is still moderately rare. Originally described in the genus Prodallia, in the same paper that the genus was formally erected in honour of the American malacologist William Healy Dall. The genus name first appeared as a nomen nudum in 1915, on a banquet brochure produced to commemorate Dall's 50th year in science. Nevertheless, this genus name is now considered to be a junior synonym of Calliotectum. The specific epithet honours Hugh M. Smith who directed the R/V Albatross expedition in the Philippines which collected the type specimen. Typical shell length around 160 mm, extremely large specimens may exceed 210 mm. Most easily confused with the very variable congener Calliotectum tibiaeforme (Kuroda, 1931) which also occurs in the Philippines, but in C. tibiaeforme the suture is adpressed and therefore the whorls appear to expand less rapidly, and the axial ribs have square cross-sections (compared to triangular in C. smithi). Shells of C. tibiaeforme also typically carry a dark spiral band just beneath the suture, which is entirely lacking in C. smithi.
Haliotis dalli Henderson, 1915<br /> HALIOTIDAE<br /> -20~30 m, By lobster diver, Fernandina Island, Galapagos Islands, Ecuador, 29.4 mm <br /> <br /> A small haliotid whose shell usually carries a red base colouration and native to the tropical eastern Pacific and western Americas, the "Dall's Abalone" is currently considered to comprise of two subspecies. The nominate subspecies H. dalli dalli (shown) is known almost only from the Galapagos Islands, Ecuador, although two specimens have been reported from Gorgona Island off Colombia. When first discovered from the Galapagos, the American malacologist William Healy Dall considered it to be conspecific with the rare western Atlantic species Haliotis pourtalesii Dall, 1881, despite the Galapagos material originating from the Pacific. Over a decade later, John B. Henderson compared the Galapagos material in more detail with the true H. pourtalesii from off Florida and found consistent differences in morphology that warranted the description of the Galapagos material as a separate species, whose name he dedicated to Dall. Inhabiting rocky substrates of subtidal waters around -20~60 m. it is a rare taxa whose scarcity likely partially attributable to its restricted, remote distribution and small size (typical shell length around 25 mm, very large specimens may reach 40 mm). This nominate subspecies is characterised by a deep, distinct channel below the selenizone (the row of holes), a character missing in the other subspecies Haliotis dalli roberti McLean, 1970. Initially described at the species rank by James Hamilton McLean and named after Robert R. Talmage of California, this subspecies is endemic to Cocos Island, Costa Rica and also has a taller spire and overall coarser spiral sculpture compared to the nominate subspecies. A smaller subspecies typically only 15 mm in shell length (very large specimens may reach 25 mm) and inhabiting slightly deeper waters around -30~100 m, H. d. roberti is even rarer than H. d. dalli. Both subspecies are probably herbivorous grazers on hard substrates like other haliotids.
Casmaria kalosmodix (Melvill, 1883)<br /> CASSIDAE<br /> -50 m, From lobster trap, O'ahu, Hawaii, U.S.A., 80.5 mm <br /> <br /> Characterised by a shell attractively marked with numerous nearly straight, narrow axial lines crossed by broad spiral bands of intermittent blotches and completely lacking spines on the outer lip, Casmaria kalosmodix is a medium-sized cassid endemic to the Hawaiian Islands (both Windward and Leeward Islands). At the time of description it was only known from two specimens, both with uncertain locality (it was speculated to be "a native of eastern seas"). The holotype, originally in the collection of the british conchologist James Cosmo Melvill who also described the species, is currently in the National Museum Wales with the other lots from the Melvill-Tomlin collection. Later in 1905 Melvill reported that he had acquired another specimen "from Ceylon" (i.e. Sri Lanka), today considered mis-localised. Later, R. Tucker Abbott recognised the Hawaiian specimens to be conspecific with Melvill's species. However, Abbott considered it to be a subspecies of the widespread Casmaria erinaceus (Linnaeus, 1758), due to the presence of two 'forms' in Hawaii, one with spines on the aperture and one without. An article by Charles Wolfe in 1976 revealed that the two Hawaiian 'forms' are actually separate species with many other consistent morphological features, the rarer untoothed form corresponding to C. kalosmodix and the toothed form he referred to as an undescribed form of C. erinaceus. The latter has recently been described as Casmaria kayae Buijse, Dekker & Verbinnen, 2013. <br /> <br /> Once sufficient specimens were examined, it became clear that Casmaria kalosmodix is actually a rather little-varied species that is difficult to be confused with either C. erinaceus or C. kayae due to its 1) lack of spines on the outer lip, 2) elongate shell with much higher spire, 3) fine, almost straight axial lines, and 4) large size. With a typical shell length around 75 mm and extremely large specimens approaching 100 mm, it is probably the largest Casmaria species. Unlike many Casmaria species such as C. erinaceus and C. kayae, it is not known to have a generally smaller nodulose form; smaller specimens have shells with slightly lower spires but are otherwise similar to large specimens. A carnivorous and predatory species probably feeding on echinoderms, it inhabits moderately depths around -20~150 m. It has always been a very rarely seen species and remains so today, most specimens known are empty or crabbed shells taken in deep-water traps; live-taken specimens are extremely scarce. The specific epithet is Greek in origin and means "beautifully marked".
Columbarium hystriculum Darragh, 1987<br /> COLUMBARIIDAE<br /> -180~200 m, Trawled, Pith Reef, Queensland, Australia, 73.4 mm<br /> <br /> With one of the most elaborately sculptured and captivating shells among columbariids, Columbarium hystriculum is an Australian endemic with a rather restricted distribution off northern Queensland. Characterised by a strongly double-spined periphery and one or two further spinous spiral cord anterior to the clearly defined anterior caina, it is impossible to mistake it for any other described columbariid species. The siphonal canal is long, with the posterior half carrying rather sparse but strong spines. The protoconch begins in a sharp tip instead of being bulbous like most other Columbarium species due to the very early part of the first whorl formed in the egg being chitinous (not calcified) and decidous upon hatching. Although a little-varied species, individuals often have different preservation conditions of the spines and worn specimens give a much less thorny impression. An uncommon carnivorous and predatory gastropod feeding on tube-dwelling polychaete worms like other columbariids, it inhabits soft bottoms of moderately deep water around -150~400m. Typical shell length around 70mm, extremely large specimens may exceed 95mm. The most similar congener, Columbarium harrisae Harasewych, 1983, is not easily confused with it since C. harrisae only carries a single row of spines on the periphery and therefore has a much less spiny appearance.
Bayerotrochus charlestonensis (Askew, 1987)<br /> PLEUROTOMARIIDAE<br /> -120 m (-400 ft.), Taken by submersible, Off Curaçao, Lesser Antilles, Caribbean Sea, Ex-coll. Barry B. Brown, 73.0 mm <br /> <br /> The "Charleston Slit Shell" is one of the most enigmatic living pleurotomariid species, known only from a handful of specimens. Originally described from a single individual taken in an area known as the "Charleston Bump" east of Charleston, South Carolina, USA by the now-decommissioned submersible "Johnson Sea Link", it was placed in the genus Perotrochus at the time and later included in the genus Bayerotrochus when it was erected in 2002 to house thin-shelled, turbiniform species of living pleurotomariids once referred to as "Perotrochus Group B". Since its description, a number of additional specimens have surfaced sporadically in a variety of locations in the western Atlantic including Florida, Honduras, Martinique, and the specimen shown originates from Curaçao. Its distribution is therefore much wider than originally thought, ranging from North Atlantic off South Carolina to throughout the Caribbean Sea. However, it remains an extremely rare species with only one to a few specimens known from each locality it has been found in. <br /> <br /> A carnivorous grazer mainly feeding on sponges like other pleurotomariids, it inhabits rubble bottoms and steep cliffs with a known bathymetric range of approximately -100~400 m. The collection depth of the holotype was written as 213 m on the description paper, but this was erroneous and the correct depth is apparently 390 m according to records of the Smithsonian National Museum of Natural History where it is housed. <br /> <br /> The early whorls are rather flattened, giving it a characteristically domed spire profile. The few known examples vary just slightly in spire height and shell profile but differ much more significantly in colouration, with the base colour ranging from creamy white to yellow to deep brownish orange. Darker 'flame-like' streaks are present and overlaid on the base colour, but the density also vary somewhat among the specimens; specimens with darker base colouration also have relatively darker overlaid streaks. As typical for the genus Bayerotrochus, the shell is very thin and light for the size. <br /> <br /> Morphologically, it is most similar to the also very rare congener Bayerotrochus pyramus (Bayer, 1967) which is distributed across most of the Caribbean Sea, with most specimens being from Navassa Island off Haiti, Guadeloupe (type locality), and St Lucia. The two therefore overlap partly in range, although B. pyramus is said to be typically found in deeper waters around -400~650 m (but has been recorded as shallow as -250 m). These two species are most significantly different in spire height and the resulting overall shell shape, with B. pyramus having an even more strongly flattened spire than B. charlestonensis; this difference is present from the early teleoconch whorls onwards to the final whorl. Bayerotrochus charlestonensis is also much larger, with a typical shell diameter around 75 mm and exceptionally large specimens exceeding 95 mm, compared to B. pyramus with a typical diameter around 45 mm and the largest specimens reaching 65 mm. As many living pleurotomariid species are known to exhibit tall-spired and short-spired forms that were given different names, the true relationships among these two rare taxa await further clarification by examining a larger series of specimens to understand the range of their variability (currently difficult due to their rarity), or by molecular data comparing their genetic distance.
Ephippodontoana mcdougalli (Tate, 1889)<br /> GALEOMMATIDAE<br /> -8 m, Dived in shrimp burrow, Under heavy rock in a swell-prone area, Marion Bay, South Australia, Australia, Leg. Mark Wilkin, 2017, 11.5 mm <br /> <br /> The spectacularly ornamented "McDougall's Shrimp Burrow Lepton" is a relatively large galeommatid bivalve endemic to the southern coast of Australia. Like a number of species in Galeommatidae it lives commensally with other animals, in this case in the burrow of shrimps either underground or in sponges where it lives attached to the wall; in shallow waters down to about -15 m deep. Water currents generated by the shrimp are considered to help with its feeding, since it is a filter-feeder. The soft parts are much larger than the shell, and the valves are actually completely enveloped by folds in the mantle meaning the shell has effectivelfy been internalised. The mantle folds carry dense (persumably sensory) papillae. The foot is large, muscular, and divided into three lobes. When on the move the animal 'creeps' more like a snail rather than a typical bivalve, as is typical in Galeommatidae. During locomotion the valves are spread out flat and carried dorsally, the two valves together forming a disc shape. Like many galeommatids its shells cannot be completely closed when alive due to the large size of the foot. It is a rarely seen species especially when alive, partly due to its small size and very specific and cryptic habitat. Typical shell length around 8 mm, very large specimens may exceed 13 mm. Originally described in the genus Ephippodonta, the new genus Ephippodontoana was erected to house it in 1951 by the Japanese malacologist Takashige Habe, which remains monotypic to date and it is difficult to confuse with any other species due to its characteristic sculpture. It shows little intraspecific variation except the density and strength of the nodulous sculpture. The "Lepton" in its vernacular name is a remnant from when it used to be considered a member of Leptonidae, which is a junior synonym of Lasaeidae.
Euprotomus hawaiensis (Pilsbry, 1917)<br /> STROMBIDAE<br /> -32 m (-105 ft.), Live in octopus hole, Makaha, Oahu, Oahu, Hawaii, U.S.A., 1985/vii/18, Leg. Chris Takahashi, 64.6 mm <br /> <br /> The "Hawaiian Conch" is a striking strombid endemic to the Hawaiian Islands (including the Midway Atoll), and is one of the most sought-after collector's item in its family. Most specimens have been found either dead and buried in sand or crabbed, even these are very scarce; such specimens usually have lost much of the colouration. Fresh dead specimens retaining good colours are even rarer, live-taken specimens like the one shown here are exceedingly rare. It inhabits sand and rubble bottoms; it is apparently nocturnal and likely feeds on minute algae like other strombids. Although usually found in depths between 20~50m, it is said to live as shallow as -5m; it can even be found beached (after storms), albeit very rarely. Typical shell length around 75mm, extremely large specimens are known to exceed even 110mm. It is most closely related to Euprotomus vomer (Röding, 1798) which ranges widely in the western Pacific from Japan to Queensland, Australia to Niue to New Zealand. In fact, E. hawaiensis has been treated as a subspecies of E. vomer, as E. vomer hawaiensis for extensive periods of time, and only relatively recently has it become widely recognised as a full species in its own right. It is easily separated from E. vomer by the following key characters: 1. The lack of a distinctive dark brown patch near the columellar in the posterior part of the aperture; 2. Overall stronger spiral sculpture especially just above the suture; 3. The lack of obvious axial "zig-zac" lined pattern on the spire; 4. A taller spire, on average. Its type locality is Pearl and Hermes Atoll in the Northwestern Hawaiian Islands.
Euhadra murayamai Habe, 1976<br /> CAMAENIDAE<br /> Mt. Myojo, Itoigawa, Niigata Prefecture, Japan, 31.7 mm <br /> <br /> The "Murayama's Hadra Snail" is an exquisite member of the east Asian genus Euhadra (Camaenidae: Bradybaeninae), instantly distinguishable from all other congeners by its very flattened shell and being one of just a handful of normally sinistral species in the genus. This is one of the most readily identifiable Euhadra species, of which many require comparisons of the genitals to distinguish. From genital features and other anatomical characteristics, it is considered to be quite distant from other sinistral Euhadra species and therefore most likely switched to growing a sinistral shell independently and in convergence. An endemic species of Japan, it has an extremely restricted distribution range, being only known from limestone cliffs and crevices between about the elevation of 600~1200 m in Mt. Myojo, Niigata Prefecture. A herbivorous grazer feeding on the bark and leaves of shrubs, it hides in cracks and holes in limestone at day and comes out to feed at night. The flattened shell is considered to be adaptive in enableing it to access narrower cracks for better protection during the day. The banding pattern on the shell is quite consistent and consists of four bands in typical positions for genus Euhadra. In this species the two bands on the suture and around the umbilicus are especially dark coloured with the one below the suture weaker, the band above the suture is only weakly stained or even absent. It is a rarely seen species mostly due to its very narrow distribution and the difficulty in accessing the vertical limestone cliffs which it inhabits. Typical shell diameter 30 mm, very large specimens are known to exceed 40 mm. Individuals tend to grow larger in higher elevations with specimens exceeding 35 mm being almost exclusively found on the summit, although the reason is unknown. It is named after Mr Hitoshi Murayama, the Japanese conchologist who discovered it in 1971 and sent the specimens to Dr. Takashige Habe for description.
Perotrochus lucaya Bayer, 1965 <br /> PLEUROTOMARIIDAE<br /> -275 m, Taken by submersible, Grand Bahama Island, Bahamas, 42.5 mm <br /> <br /> A small, light coloured pleurotomariid, the "Lucayan Slit Shell" is characterised by a thick, robust shell with a domed spire and very finely beaded sculpture. Known definitively only from the Bahamas, it ranges from Grand Bahama Island to Eleuthera to Great Inagua Island and is found between -250~400 m deep. Vast majority of specimens have been taken off Grand Bahama Islands either by trawling or through the use of manned submersibles, including the holotype (and the only specimen known at the time of description) which was trawled between -275~366 m deep in the Northwest Providence Channel by R/V GERDA off Lucaya, a town in Freeport, Grand Bahama Island. The Bahamas is located in the Lucayan Archipelago named for the 'Lucayan people' (derived from Taino 'Lukku-Cairi', meaning 'island people'), the original inhabitants of the Bahamas prior to the arrival of Europeans. Although Bayer did not specify an etymology in his description, the specific epithet 'lucaya' likely refers to the type locality of Bahamas in a broad (the archipelago or the country) or narrow (the town of Lucaya) sense. There is actually a single record of this species supposedly from Venezuela (311 m deep, off Caracas), but this range extension has not been substantiated by further specimens and the collection data for that single specimen is questionable. A spongivorous gastropod, it inhabits steep vertical cliffs and is often found associated with sponges upon which it feeds. <br /> <br /> The spire height is rather variable in this species, ranging from high-spired and strongly domed specimens to those with lower spires where the shell height is similar to the diameter (ratio of height to diameter ranging between 1:1 to 1.2:1). Sides of the spire typically straight-sided but can also be weakly stepped. Various intergrades of these varying spire morphology co-occur and the sculpture does not differ significantly among them, indicating that they are all forms of a single species. Like many pleurotomariids the periphery of the base tends to become more convex in larger specimens. The colouration is white to pale beige with sparse axial streaks of darker beige, the frequency of such 'flame-like' streaks vary substantially among individuals. Although a yellowish brown periostracum is present at the shell edge, on other parts of the shell typically only traces remain at the suture. The foot is whitish with cloud-like patterns of light beige, the head and neck carry reddish horizontal streaks. Typical shell height around 35 mm, the largest specimens are known to exceed 60 mm. <br /> <br /> It is most similar to Perotrochus quoyanus (Fischer & Bernardi, 1856), especially the nominal subspecies which inhabits the Carribean Sea. Perotrochus lucaya differs from P. q. quoyanus, by having a much more domed and generally taller, less stepped spire, as well as a lighter colouration. The sculpture also differ between the two, with that of P. lucaya being dominated by fine and regular beading and P. q. quoyanus being dominated by strong spiral cords. The other subspecies of P. quoyanus, P. q. insularis Okutani & Goto, 1985, is endemic to Bermuda and can be differentiated from P. lucaya by its much coarser beading, more stepped spire, and larger size on average. Perotrochus quoyanus is not known from the Bahamas and the two species are therefore not known to co-occur.
Zoila marginata (Gaskoin, 1849) <br /> CYPRAEIDAE<br /> -15 m, Dived in a cave, Carnac Island, Western Australia, Australia, 55.2 mm <br /> <br /> The "Broad-Margined Cowrie" is a species of the Australian endemic genus Zoila characterised by light background colouration and sharp, well-developed margins around the base of the shell. Like other Zoila species it is very variable in shell morphology and colouration; the shell form can vary from oval (shown) to very slender and elongated, and the amount of pigmentation and spotting also varies greatly both on the dorsum and on the base. Ranging between Jurien Bay to Augusta to Cape Recherche in the southwestern Australia, there are some general trends in shell morphologies from various localities. For example, those from the southern population around Albany tend to have taller dorsal humps and those from the western populations tend to have darker pigmentation above the extremeties. Nevertheless, the variability within each population is so great that it is often difficult to discern a shell's locality from just its morphology. The overall darker and more slender form from the Perth area has been given the name consueta Biraghi, 1993, but this name is now considered to be a junior synonym of Z. marginata. The locality of the holotype is not known and has been widely debated from the shell morphology, with some suggesting around Albany from the tall dorsum and some arguing for a western origin due to the higher abundance of specimens with finely reticulated dorsal patterns there. <br /> <br /> It is currently split into three subspecies, with the nominal subspecies ranging between Jurien Bay to Augusta in about -5~50 m deep, Z. m. albanyensis Raybaudi, 1985 between Cape Recherche to Cape Leewin in approximately the same depths, and the recently described deep-water subspecies Z. m. nudispira Lorenz, 2020 from around -100 m deep in the southern part of the species' range. Zoila m. albanyensis typically lacks dorsal spotting, with the dorsum being entirely white or with large, cloudy tan-coloured blotches (f. nimbosa Raybaudi, 1994), and is also usually more inflated and has a wider aperture. The subspecies Z. m. nudispira is rather similar to Z. m. albanyensis but lacks most of the callous on the spire making it mostly exposed (hence the name 'nudispira'), and is also generally smaller and lighter. The typical shell length of both the nominal subspecies and Z. m. albanyensis is around 60 mm (very large specimens approach 80 mm; Z. m. albanyensis is slightly larger on average), while for Z. m. nudispira the average is just shy of 50 mm (very large specimens exceeding 55 mm). Mostly found in underwater caves and crevices, it is a spongivorous gastropod and is mostly found living on its food sponge. Due to the shallow depths and rather wide range Z. m. marginata and Z. m. albanyensis are both quite common, while Z. m. nudispira is still rare. Due to the partly overlapping ranges among the three subspecies, further researches are required to understand their relationships. <br /> <br /> A couple of taxa previously treated as subspecies of Z. marginata including Z. ketyana (Raybaudi, 1978) and Z. orientalis Raybaudi, 1985 are currently treated as separate species in their own right. Between Dongara and Jurien Bay a population that appears to connect Z. marginata and Z. ketyana exists and has been informally referred to as "f. intermediata"; molecular data has shown that this population should be considered as Z. ketyana and not Z. marginata, although whether these two taxa are truly separate on a species level remains a debated topic.
Fusimorio deshayesii (Duval, 1841) <br /> CANCELLARIIDAE<br /> -70 m, Dredged, Off Île de Gorée, Dakar, Senegal, 33.1 mm <br /> <br /> Better known by the name Loxotaphrus deshayesii, the "Morum-like Nutmeg" is an enigmatic species characterised by a peculiar shell morphology resembling a mixture of various genera from different caenogastropod families like Galeodea (Cassidae), Morum (Harpidae), and Cancellaria (Cancellariidae). Its familial placement has been a subject of debate since the original description as Cassidaria deshayesii Duval, 1841 in Cassidae, Cassidaria Lamarck, 1816 being a junior synonym of Galeodea Link, 1807. Later the genus Loxotaphrus Harris, 1897 was erected to house similar fossil species from Miocene described in Buccinidae, and it was then moved here, as Loxotaphrus deshayesii. Various species included in Loxotaphrus were originally described in a wide range of families such as Cassidae, Buccinidae, Fasciolariidae, and Toniidae, exemplifying the puzzling shell morphology of this genus. The work by Alan G. Beu and Phillip A. Maxwell in 1987 revised and expanded the concept of Cancellariidae to include a number of genera originally placed in other families based on re-evaluation of shell characteristics, including Loxotaphrus in their newly erected subfamily subfamily Plesiotritoninae based on protoconch and details of the shell sculpture. The moving of Loxotaphrus to Cancellariidae remained questionable for many due to the lack of strong columarllar plaits, a key character of Cancellariidae. This was until in 2011 when a paper by Maria V. Modica et al. examined the radula and anatomy of two living species L. deshayesii and L. rosadoi to confirm that both indeed supported a placement in Plesiotritoninae, Cancellariidae. Importantly, they also confirmed this placement using a phylogenetic reconstruction based on DNA sequences (12S and 16S rRNA genes), settling the debate. Recently, the genus Fusimorio Sacco, 1896 was deemed to be a senior synonym of genus Loxotaphrus, changing the name of this species once again to Fusimorio deshayesii. <br /> <br /> Ranging between Western Sahara and Ivory Coast, it is a western Africa species living on soft bottoms of moderate depths around -20~80 m deep. Although the mode of feeding is unknown, its anatomy is suggestive of suctorial feeding similar to other cancellariids, probably on the body fluid of other animals. It was once extremely rare, and although some specimens have been recovered in the recent few decades it remains a rare and elusive species. Though it can be hardly confused with any other described species, individuals do exhibit some variation in shell morphology, especially the strength and spacing of axial varices and nodules on the varices; the shell colouration can also vary from whitish to dark brown. Typical shell length around 25 mm, very large specimens may exceed 35 mm.
Hysteroconcha multispinosa (Sowerby II, 1851) <br /> VENERIDAE<br /> On beach after a storm, Manabi Province, Ecuador, 2020/ii, 34.8 mm <br /> <br /> The spectacularly ornamented "Multi-spined Comb Venus" is one of a few heavily spined venerid clams in the genus Hysteroconcha. Ranging between Nicaragua and Peru in the eastern Pacific Ocean, it is a filter-feeding bivalve inhabiting sandy bottoms of shallow waters down to about 30 m deep. When alive, it burrows in sand with its spines positioned upwards, likely used as a defence against predators trying to snip off its siphons. Although locally not uncommon, not many specimens reach private collections, especially ones retaining long spines and without holes from predation by naticids. Majority of specimens have been collected on the beach after strong storms passed by, likely a reason behind many broken spines. Typical shell length including spines about 30 mm (25 mm without spines), very large specimens may exceed 40 mm (35 mm without spines). Although less well-known compared to its larger cousins H. dione (Linnaeus, 1758) from the western Atlantic and H. lupanaria (Lesson, 1831) also from the eastern Pacific, it is certainly no less spectacular, with much denser spines than either of them. The colouration of H. multispinosa is brownish red, rather than being violet to lavendar like the other two species. The two Pacific species, H. multispinosa and H. lupanaria, do co-occur, but they are easily distinguished since H. lupanaria is much larger, with more sparse but longer spines, and lacks the strongly erected ribs in H. multispinosa. Previously different authors have placed H. multispinosa under other genera including Pitar, Pitaria, and Cytheraea. Callista longispina Mörch, 1861 is considered to be a junior synonym.
Triplofusus giganteus (Kiener, 1840) <br /> FASCIOLARIIDAE<br /> -9m (-30 ft.), Dived on sand, Off Longboat Key, Florida, U.S.A., Leg. & Ex-coll. Peggy Williams, 1981/x/18, 365.3 mm <br /> <br /> With an astounding record shell length of 604.8 mm and an average shell length of about 380 mm, the "Florida Horse Conch" is a giant among the living gastropods. It is not only the largest of all living fasciolariids, but also the second largest living shelled gastropod of all, with only Syrinx aruanus (Linnaeus, 1758) reaching a greater shell length. Ranging between North Carolina, U.S.A. and Yucatan, Mexico, it inhabits soft bottoms from low intertidal down to about 30 m deep. It is a locally common species in Florida, and more uncommon elsewhere in its range. A carnivorous and predatory gastropod, it feeds on a variety of other large marine snails such as Fasciolaria tulipa (Linnaeus, 1758) and Sinistrofulgur perversum (Linnaeus, 1758). The head-foot of its soft parts is vivid orange in colouration and easily visible underwater when it is actively moving or feeding. When alive the shell is covered by a thick, dark brown periostracum. Quite variable in colouration, specimens can range from almost completely white to brownish; the most typical colouration consists of alternating spiral bands of darker and lighter orange (as shown). The strength of sculpturing on the shoulder is also very variable, ranging from completely smooth to bearing numerous small nodules to having a few strong, large nodules per whorl. <br /> <br /> It is famously known as the State Shell of Florida, a designation which was formally signed in 1969 after considerable efforts by members and friends of the Palm Beach County Shell Club. The 604.8 mm world record sized specimen is being displayed in the Bailey-Matthews National Shell Museum. <br /> It is the type species of Triplofusus erected in 1953; though some authors have placed it in the genus Pleuroploca, that genus is currently considered to be restricted to the Indo-West Pacific and therefore this species is more appropriately placed in Triplofusus. <br /> <br /> Unusually for such a large and well-known species, there have been a lot of confusion and controversy regarding the appropriate scientific name for this species. The first published name for it is Murex gigas Gmelin, 1791, but this name was unavailable due to being preoccupied by Murex gigas Born, 1780 (which is actually more 'gigas', being a synonym of Syrinx aruanus). Then Sowerby I published the name Fasciolaria papillosa Sowerby I, 1825 in an auction catalogue, but the description was very short and the specimen he based the name on is now considered lost. Fifteen years later Kiener described Fasciolaria gigantea Kiener, 1840, which was richly illustrated with thorough descriptions -- the type specimens illustrated and thus the name are clearly referrable to the Florida Horse Conch (though the type locality was given as "l'océan Pacifique?"). Though the specimen figured by Kiener could not be located in a search by Snyder et al. in 2012, they located and recognised a syntype in Muséum National d'Histoire Naturelle, Paris. <br /> <br /> Over the years, many authors argued backwards and forwards about whether Sowerby's name actually referred to the same species and would have priority, but since Sowerby's description was vauge and the lost specimen was small (3.7 in or 94 mm in shell length), it was difficult to know for sure if it was indeed a specimen of the Florida Horse Conch. Recently, a publication in 2017 by David P. Berschauer argued again for Sowerby's name taking priority over Kiener's, and attempted to designate a specimen illustrated by Reeve in 1847 as the neotype of Sowerby's name F. papillosus. Following this, William G. Lyons and Harry G. Lee submitted an Application to the International Commission on Zoological Nomenclature, registered as Case 3755, to conserve the usage of Kiener's name. They presented a detailed literature survey with numerous lines of evidence for considering Sowerby's name to be a nomen dubium instead, and pointed out that Berschauer's designation of its neotype does not meet requirements stated in Art 75.3 of the International Code of Zoological Nomenclature and is therefore invalid. They also stated that since Kiener's name has been prevailingly used compared to Sowerby's, the conserved usage of Kiener's name would help to maintain nomenclatural stability. After correspondence between the Commission and the two authors, their case was accepted for publication as a Nomenclatural Note in the Bulletin of Zoological Nomenclature (an official publication by the Commission) and the case was closed. Therefore, the correct scientific name to use for the Florida Horse Conch is currently Kiener's, now properly known as Triplofusus giganteus (Kiener, 1840). Fasciolaria reevei Jonas, 1850 was a name proposed for the smooth-shoulder form, and is now considered a junior synonym.
Sultana yatesi (Pfeiffer, 1855) <br /> ORTHALICIDAE<br /> +1900 m, In native forest, Rodriguez de Mendoza, Amazonas, Peru, 2020/vi, 81.4 mm <br /> <br /> The visually striking "Yates' Sultana Snail" is characterised by an elongate shell with various degrees of sinuous axial patterning crossed by up to four spiral bands, and is one of a number of charismatic Sultana snails endemic to the central Andes in South America. It is currently considered to be a species with very variable shell colouration and patterning, both within and among populations or specific localities. The base colouration ranges from yellowish to reddish to purplish, and the development of both axial and spiral patterning also appears to be very variable (though specimens from the same locality do tend to be more similar). The specimen shown has an exceptional pattern with continuous bright yellow axial streaks on very dark spiral bands, a very similar specimen won the Shell of the Show at the 2019 Paris Shell Show. <br /> <br /> Originally described in the genus Bulimus, its type material is currently housed in the Natural History Museum, London. The type locality was given as "Meobamba, Eastern Peru", taken to mean Moyobamba in San Martín Department. In the original description Pfeiffer did not mention the number of specimens examined, and the name-bearing type was unclear. Later in 1985, Breure and Schouten selected a specimen figured in Pfeiffer's description as the lectotype; two paralectotypes are now known from the Hugh Cuming collection. A number of similar species described later, including Porphyrobaphe latevittata Shuttleworth, 1856, P. sublabeo Ancey 1890, P. grandis Rolle 1902, and P. sarcostoma Ancey, 1903 have now been formally synonymised with S. yatesi (by Richardson, 1993) on the basis that they have very similar shell shapes and that their colourful patterning consists of similar basic elements. Sultana vicaria (Fulton, 1896) was once also synonymised with S. yatesi by Richardson, but was later rehabilitated by Breure & Avila in 2016 due to its stouter shell and uniform colouration. The taxon Sultana galactostoma (Ancey, 1890) also has a similar shell shape to S. yatesi (but with whitish yellow colouration instead of colourful patterns) and it has been treated as a subspecies of S. yatesi, as S. y. galactostoma, by some authors. However, it has recently become clear that it is only definitively known from Ecuador with the records from Peru being erroneous; suggesting that it may be more appropriately treated as a separate full species afterall. Clearing up the true relationship among these taxa requires future anatomical and genetic evidences. Under the current definition, the range of S. yatesi spans across two Departments of Peru, namely Amazonas and San Martín, in high mountanous areas around +1000~2000 m in elevation; if S. y. galactostoma is considered as a subspecies then this extends the range of the species into Ecuador. <br /> <br /> Typical shell length around 80 mm, extremely large specimens may exceed 100 mm. Although used to be extremely scarce, a recent surge in the supply of Peruvian orthalicid snails rendered S. y. yatesi relatively easy to obtain today. Nevertheless, since it is a very variable species prone to scarring, high-quality specimens with striking patterns are still highly sought-after by collectors. <br /> <br /> It was named after a Mr. Yates who provided the material for its description. Today it is often listed under the subgenus Metorthalicus, for which it is the type species. In the past some authors have placed it under the genus Porphyrobaphe, although this is now no longer accepted and that genus is considered to be restricted to a group of species inhabiting Colombia and Ecuador.
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