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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.

Calliostoma rosewateri Clench & Turner, 1960<br /> CALLIOSTOMATIDAE<br /> -250 m, Collected by the submersible "Curasub", Curaçao, Lesser Antilles, 2014, 28.5 mm <br /> <br /> A lustrous and radiant shell with finely beaded double-keeled shoulder characterises the "Rosewater's Top", a beautiful Caribbean calliostomatid ranging from Florida, U.S.A. to Trinidad and Tobago. A carnivorous grazer inhabiting hard bottoms of rather deep waters ranging between about 200~500 m depth, it most likely feeds on corals and other sessile animals as is typical for calliostomatids. Though overall a little-varied species, the development of dark colour patches on the shell vary greatly among individuals; these patches carry violet hue when fresh but rapidly fades to reddish brown. The shell surface carries a metallic, golden sheen, making this rather rare species a much coveted collector's item. <br /> <br /> Typical shell diameter around 30 mm, though very large specimens may reach even 45 mm. Among the many closely-related deep-water Caribbean calliostomatids with beaded spiral cords, it is perhaps most similar to Calliostoma oregon Clench & Turner, 1960 which also has a double-keeled shoulder. These two species are separable in that the shell of C. oregon has straight sides to the spire as opposed to the slightly concave ones in C. rosewateri, and that O. oregon has fewer spiral cords with coarser beading. The shell size of C. oregon is much smaller than C. rosewateri, being typically only around 20 mm and the largest individuals reaching just 30 mm.
Offadesma nakamigawai Kuroda & Horikoshi, 1952<br /> PERIPLOMATIDAE<br /> Shizuoka Prefecture, Japan, 51.2 mm <br /> <br /> An unusual periplomatid bivalve, the "Nakamigawa's Lantern Shell" is characterised by a paper-thin, strongly inequivalve shell where the left valve is much smaller than the right valve which envelopes it. Originally described based on a single specimen with damaged but articulated valves collected off Zushi in Sagami Bay, it is usually considered an endemic species of central Japan -- though a morphologically similar specimen was collected in the Philippines in 2014 and may represent a significant range extension. The holotype was collected by Korokuro Nakamigawa, a Japanese collector living in Kamakura, after whom this species was named after. Living in subtidal waters down to about -70 m deep, it usually remains buried in soft or sandy mud and is an infaunal filter-feeding bivalve. A transverse crack is present near the umbo, a feature typical of Periplomatidae and Laternulidae; the ligament is attached to large, spoon-like chondrophores. Typical shell length around 50 mm, very large specimens can reach 75 mm. <br /> <br /> An exceedingly rare species, it is mostly known from broken fragments washed up on shore after storms, articulated valves being virtually impossible to obtain. In addition to its apparently intrinsic low population density, an important reason for this is that the valves are very brittle and being aragonistic they rapidly disintegrate after the animal’s death. With a graceful Japanese name literally meaning the "long-tailed celestial robe of the dragon palace" ("Onaga-Ryugu-Hagoromo") added on top of its scarcity, it has attained a mythical status among Japanese collectors and a most sought-after species. The renowned Japanese palaeontologist and malacologist Tokio Shikama (1912-1978) wrote about the only specimen in his collection "I thought I was dreaming when I collected this species" (Selected Shells of the World Illustrated in Colours Vol. II, 1964), and another famed malacologist Katsura Oyama (1917-1995) was said to have greatly cherished a mere fragment of a shell in his collection. <br /> <br /> Among living bivalves it can only be confused with one species, its only extant congener Offadesma angasi (Crosse & Fischer, 1864) ranging from Australia to New Zealand. 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 (80 mm, up to 100 mm). The inflation of valves is also similar among the two species when examining a larger series of O. angasi. These two species are actually more readily separable in that the left valve of O. nakamigawai is much smaller than the right valve whereas in O. angasi they only differ very slightly. Typically, O. nakamigawai also has a more clearly constricted posterior beak than O. angasi but both species are somewhat variable in overall shell form and this is not always obvious. These two species are clearly very similar and the true relationship between them warrants molecular studies plus hopefully the finding of more specimens from geographically intermediate localities like the Philippines.
Morum lindae Petuch, 1987<br /> HARPIDAE<br /> -120 m, Trawled on sandy bottom, Off Cabo de la Vela, Guajira Peninsula, Colombia, 1990’s, 41.1 mm <br /> <br /> An intricately sculptured harpid with a broad shoulder and ornamented with criss-crossing axial and spiral ribs, the "Linda's Morum" is a Caribbean species ranging between Colombia and Venezuela. Inhabiting moderately deep waters around -50~200 m, it most likely feeds on small crustaceans like other Morum species. A rather rare species, vast majority of the known specimens have been trawled or dredged off Colombia. The overall colouration is rather variable and can range from light tan to very dark purple, specimens with dark colouration are extremely rare. Similarly, the columellar shield can vary in colour from white to dark purple. Typical shell length around 35 mm, very large specimens may reach 45 mm. <br /> <br /> This species was named in honour of Linda Petuch, wife of the malacologist Ed Petuch who named it. It is most closely allied to Morum dennisoni (Reeve, 1842) with which it co-occurs in the western Atlantic. The two species have sometimes been confused, but are actually easily separable in that M. lindae has much stronger axial sculpture with the varices becoming raised like sharp blades and typically has a stronger shoulder compared to M. dennisoni.
Paralepetopsis polita Chen, Zhong, Qiu & Sun, 2023<br /> NEOLEPETOPSIDAE<br /> Top & Left: Paratype #1 (NSMT Mo-79367), 7.0 mm; Right: Holotype (TMBC031004), 7.9 mm; Bottom: Paratype #2 (NSMT Mo-79368), 6.4 mm <br /> -1361 m, On the shell of the vesicomyid clam Archivesica marissinica, Haima methane seep (16°41.6561'N, 110°23.8165'E), South China Sea <br /> <br /> A deep-sea limpet with a smooth, semi-transparent shell, Paralepetopsis polita is so far only known from the Haima methane seep in the South China Sea. A grazing gastropod, it usually lives on the shell surface of the large vesicomyid clam Archivesica marissinica Chen, Okutani, Liang & Qiu, 2018 (which has symbiotic bacteria living inside its gill cells that oxidise hydrogen sulfide to generate energy) and is thought to feed on the bacterial film growing on the clam. Typical shell length around 5 mm, very large specimens may exceed 8 mm. Although only uncommon at the Haima seep, the restricted and deep nature of its preferred habitat means it is very rarely collected and only a few specimens are known at the moment. <br /> <br /> It has a characteristically neolepetopsid-type radula with articulating shafts and a solid central tooth, but molecular phylogeny surprisingly nested it within Lepetidae instead. This indicates there are likely two separate lineages of true limpets with this radula type, and molecular data for the type species of Paralepetopsis is needed in the future to resolve the position of this genus. The smooth, thin shell with a straight to concave anterior slope differentiates it from other species currently assigned to Paralepetopsis.
Shinkailepas conspira Beck in Chen & Sigwart, 2023<br /> PHENACOLEPADIDAE<br /> Holotype (MNHN-IM-2000-38688)<br /> -1842 m, Hine Hina hydrothermal vent site (22°32'S 176°43'E), Lau Basin, Taken by the manned submersible HOV Nautile, BIOLAU cruise dive BL01, 1989/v/13, 21.3 mm <br /> <br /> A large-sized phenacolepadid limpet, Shinkailepas conspira is only known from deep-sea hydrothermal vents at Lau Basin in the southwestern Pacific where it inhabits surfaces of chimney structures and grazes on bacterial mats. Like all phenacolepadids it uses haemoglobin instead of haemocyanin as the oxygen-transporting protein and therefore when alive its soft parts are reddish. Though a common species in the narrow local habitat where it occurs, due to its extremely limited distribution at deep water vent fields it is rarely sampled. <br /> <br /> Typical shell length around 15 mm, very large specimens like the holotype shown here can exceed 20 mm. Its large size combined with the strong concentric ribs on the shell, an asymmetrical operculum, numerous paddle-like flaps on the epipodium, and hypertrophied oral and epipodial lobes together distinguishes it from other described Shinkailepas species. This species was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023.
Bathyacmaea nadinae Beck in Chen & Sigwart, 2023<br /> PECTINODONTIDAE<br /> Holotype (MNHN-IM-2000-38676)<br /> -1859 m, Hine Hina hydrothermal vent site (22°32'S 176°43'E), Lau Basin, Taken by the manned submersible HOV Nautile, BIOLAU cruise dive BL02, 1989/v/14, 23.0 mm <br /> <br /> With a restricted distribution in deep-sea hydrothermal vents of Lau and North Fiji Basins in the southwestern Pacific, Bathyacmaea nadinae is a large pectinodontid limpet inhabiting diffuse flow regions surrounding active smoker chimneys. Like other Bathyacmaea species, it is a grazing gastropod that feeds on microbial mats growing on various substrates in the hot vent environment, such as shells of bathymodioline mussels and chimney surfaces. Typical shell length around 15 mm, very large specimens can approach 25 mm. Unlike other Bathyacmaea species in the western Pacific which are often locally abundant where they occur, B. nadinae is a very rare species known from only about a dozen live-taken specimens plus some empty shells. <br /> <br /> This species was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023. This species was named in honour of Lothar Beck's daughter, Nadine Beck.
Lepetodrilus fijiensis Beck in Chen & Sigwart, 2023<br /> LEPETODRILIDAE<br /> Holotype (MNHN-IM-2000-38682)<br /> -1750 m, Vai Lili hydrothermal vent site (23°13'S 176°38'E), Lau Basin, Taken by the manned submersible HOV Nautile, BIOLAU cruise dive BL12, 1989/v/24, 11.0 mm <br /> <br /> A lepetodrilid vetigastropod limpet endemic to deep-sea hydrothermal vents, Lepetodrilus fijiensis is only known from Lau Basin (Vai Lili and Hine Hina vent fields) and North Fiji Basin (White Lady and Mussel Valley vent fields) in the southwest Pacific between 1700-2750 m deep. Living on hard substrates such as chimney surfaces and mussel shells, it is thought to combine filter-feeding and grazing on bacterial mats for nutrition like other Lepetodrilus limpets. A large-sized species for Lepetodrilus, the average shell length is about 8 mm while the largest known specimen is 12 mm. <br /> <br /> It is morphologically very similar to the sister species Lepetodrilus schrolli Beck, 1993 with a more western distribution in Manus Basin, southwest Pacific, but can be distinguished by having a much larger shell (L. schrolli averages around 3 mm and the largest known specimen is only 5.5 mm in shell length) with a more posterior apex, a radula with the central tooth having a longer cusp, and a deeper pallial cavity with shorter shell muscles. It is very abundant at the vent fields where it occurs, forming dense assemblages on hard substrata. Nevertheless, due to the extremely limited distribution at vent fields, it is rarely sampled. <br /> <br /> This species was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023.
Pyropelta ovalis Beck in Chen & Sigwart, 2023<br /> PYROPELTIDAE<br /> Paratype #2 (NSMT-Mo 79406)<br /> -2000 m, White Lady hydrothermal vent site (16°59'S 173°55'E), North Fiji Basin, Taken by the manned submersible HOV Nautile, STARMER II cruise dive PL21, 1989/vii/16, 5.5 mm <br /> <br /> Only known from two deep-sea hydrothermal vent fields in the southwestern Pacific (White Lady vent field, North Fiji Basin and Hine Hina vent field, Lau Basin), Pyropelta ovalis is a medium-sized pyropeltid limpet with an elongate, narrow, oval shaped shell. As typical for pyropeltid limpets inhabiting hydrothermal vents, the shell is usually heavily corroded on the dorsal surface, revealing a mesmerising pattern of irregular concentric lines represnting different degrees of corrosion at various parts of the shell. Pyropeltid limpets are considered to be grazers on bacterial mats growing on the hard substrates where they inhabit, and this species appears to be no exception. The handful of known specimens are little-varied with an average shell length just shy of 5 mm; the shown specimen is the largest one known at 5.5 mm. <br /> <br /> An elongate shell form for the genus combined with a radula with broad, rounded cusp on the central tooth and short, stiff denticles on the cusps of marginal teeth differentiates this species from other described Pyropelta species. It appears to be uncommon at the vent sites it inhabits, and this plus the great depth and rather small sizes of these sites means it is very rarely sampled. This species was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023.
Pseudorimula leisei Beck in Chen & Sigwart, 2023<br /> LEPETODRILIDAE<br /> Dorsal and lateral views: Holotype (MNHN-IM-2000-38680), 4.5 mm; Ventral view: Paratype 5 (SMF 370358), 2.7 mm <br /> -1853 m, Hine Hina hydrothermal vent site (22°32'S 176°43'E), Lau Basin, Taken by the manned submersible HOV Nautile, BIOLAU cruise dive BL03, 1989/v/15 <br /> <br /> A lepetodrilid "slit limpet" inhabiting deep-sea hydrothermal vents, Pseudorimula leisei is only known from the surface of sulfide 'chimneys' in active vent sites of North Fiji and Lau Basins, Southwestern Pacific. Due to the limpet shell form with a distinct slit, Pseudorimula was originally thought to be closely related to Fissurellidae. Later, however, molecular evidence showed that it was in fact more closely related to Lepetodrilus limpets which lack a slit but also typically inhabit chemosynthesis-based ecosystems like vents. There are only two other described Pseudorimula species, including P. marianae McLean, 1989 from the Mariana Trough, Southern Pacific and P. midatlantica McLean, 1992 from the Mid-Atlantic Ridge, Atlantic Ocean. In terms of shell morphology, P. leisei differs from both of these species in having a narrower shell with the apex positioned near to the posterior margin rather than central, and stronger radial ribs. The radular characters are also distinctive in that it has central and lateral teeth with coarse denticles and sharply pointed cusps. Though the exact diet of Pseudorimula species is unclear, they are most likely grazers that feed on bacterial mats. <br /> <br /> Typical shell length around 3 mm, very large specimens may exceed 5 mm. In larger specimens the shell surface is typically overlaid by a layer of sulfide mineral deposits which obscures the surface sculpture. Despite being locally common at the vent sites it inhabits, due to the very small size of these sites and the great depth it is very rarely sampled. It was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023. This species was named in honour of Dr Thorsten Leise, an entomologist who was a close friend of Beck when they both worked at Philipps-University of Marburg.
Symmetromphalus mcleani Beck in Chen & Sigwart, 2023<br /> NEOMPHALIDAE<br /> Holotype (MNHN-IM-2000-38688)<br /> -1842 m, Hine Hina hydrothermal vent site (22°32'S 176°43'E), Lau Basin, Taken by the manned submersible HOV Nautile, BIOLAU cruise dive BL01, 1989/v/13, 7.1 mm <br /> <br /> With the known distribution limited to deep-sea hydrothermal vents in North Fiji and Lau Basins in the southwestern Pacific, Symmetromphalus mcleani is a neomphalid snail characterised by up to 12 broad, radial ribs on the shell and a scaly periostracal margin which distinguishes it from the two described congeners. The periostracum is typically yellowish brown with a silky sheen. As typical for neomphalids it is a sexually dimorphic species, with the left cephalic tentacle being modified and enlarged into a penis in males; while in females both cephalic tentacles are of equal size. Like other congeners, it is thought to be a sessile filter-feeder based on its foot and gill morphology. Typical shell length around 5 mm, the largest specimen recorded so far is 8.9 mm. <br /> <br /> Despite being locally common at the vent sites it inhabits, due to the very small size of these sites and the great depth it is very rarely sampled. First collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, who drafted the description since at least 1997 but did not publishe it until he passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023. This species was named in honour of Dr James Hamilton McLean (1936-2016), who was the curator of Mollusca at the Natural History Museum of Los Angeles County and a renowned gastropod taxonomist.
Symmetriapelta wareni Beck in Chen & Sigwart, 2023<br /> PELTOSPIRIDAE<br /> Holotype (MNHN-IM-2000-38693)<br /> -2000 m, White Lady hydrothermal vent site (16°59'S 173°55'E), North Fiji Basin, Taken by the manned submersible HOV Nautile, STARMER II cruise dive PL12, 1989/vii/07, 4.1 mm <br /> <br /> Only known from deep-sea hot vents in North Fiji and Lau Basins (including the nearby northern Tonga-Tofau Volcanic Arc), Symmetriapelta wareni is a peltospirid characterised by a more-or-less symmetrical limpet-formed shell with scaly radial ribs. Though the vent-endemic Peltospiridae is known to be extremely variable in shell morphology among genera, this is the first limpet-shaped species with a central apex position and strong radial ribbing -- hence a new genus Symmetriapelta was named in order to house this species. The strength of ribs is very variable among individuals, and those with weaker ribs exhibit a larger number of them. However, across the whole range of rib strength the pattern of having one stronger rib followed by three to five weaker ones and another stronger rib, remains consistent. <br /> <br /> Despite being locally common at the vent sites it inhabits, due to the very small size of these sites and the great depth it is very rarely collected. It is considered to be a grazing gastropod feeding on bacteria growing on hard surfaces in vent fields. Typical shell length around 3.5 mm, very large specimens may exceed 5 mm. This species was first collected by French and Japanese joint expeditions in 1989 and studied by the German malacologist Lothar A. Beck, but the description remained unpublished until Beck passed away in 2020. Finally in 2022, Chong Chen and Julia Sigwart continued Beck's work based on his material and text, leading to its publication in 2023. This species is named after the eminent malacologist Anders Warén, curator emeritus in Swedish Museum of Natural History.
Lyria laseroni (Iredale, 1937)<br /> VOLUTIDAE<br /> Off Iluka, New South Wales, Australia, 29.2 mm <br /> <br /> Unmistakable with an unusually low spire and squat shell form for its genus, the "Laseron's Lyria" is a small volutid endemic to eastern Australia. Almost all specimens have been found in the northern half of the eastern coast of New South Wales, though there are scattered reports from more southern parts of the same state and it has also supposedly been recorded off Lord Howe Island. A very rarely seen species, almost all specimens have been collected as empty, beached shells and virtually no live-taken records are known. Occasional shells have been trawled up to about 50 m deep, and it probably inhabits sandy bottoms around this depth though this remains speculative. Though its diet is unknown, it is most likely a carnivorous and predatory gastropod feeding on invertebrate animals like other Lyria species. <br /> <br /> Early whorls carry about a dozen weak axial ribs, but these disappear in the body whorl which only carry fine spiral striae. Specimens vary considerably in colouration, ranging from pale tan to very dark brown; but how much of this is due to fading is unclear. Typical shell length around 25 mm, very large specimens may reach 35 mm. It was named in honour of Charles Francis Laseron (1887-1959), a malacologist and paleontologist who worked mostly in Sydney, Australia and described dozens of new species around the region. Its unusual shell form led to a new genus, Lyreneta, being established to house it at the time of description, though today this is recognised as a junior synonym of Lyria.
Babelomurex japonicus (Dunker, 1882)<br /> MURICIDAE<br /> -100 m, By tangle net, Bohol Island, Central Visayas, Philippines, 50.0 mm <br /> <br /> In contrast to its name, the "Japanese Latiaxis" is a coralliophiline muricid with a rather wide distribution range in the Pacific Ocean, from Japan to the Philippines to Hawaiian Islands, U.S.A. One of the most common latiaxis species, it is nevertheless one of the most attractive with a pure-white, intricately sculptured shell. Like all coralliophilines it lives in association with corals upon which it feeds by suctorial feeding. Majority of specimens are collected around 100 m deep, though its depth range is much broader between 50~400 m depth. <br /> <br /> The main source used to be deep-water gill nets and dredges in Japan, but with the advent of tangle nets in the Philippines that has become the most common source; trawls in East China Sea have also collected numerous specimens in the recent years. It is a rather variable species in terms of sculpture, especially the development of shoulder spines which can vary greatly in both length and breadth (and therefore frequency). Typical shell length around 35 mm, extremely large specimens may reach 60 mm. In Japan it is known by an elegant Japanese name,"Tennyo-no-Kamuri", meaning "Tiara of a Heavenly Maiden".
Bathybembix macdonaldi (Dall, 1890)<br /> CALLIOTROPIDAE<br /> -700 m, Trawled in nets for Royal Red Shrimp, Off Caldera, Atacama Region, Chile, 2006, 65.5 mm <br /> <br /> The magnificently sculptured "McDonald's Top" is a large calliotropid ranging between Pacific Panama and Chile. A deep-water species, it is a deposit-feeding gastropod inhabiting muddy bottoms between 200~1200 m deep; though most specimens are found between 500~1000 m deep. The holotype was collected off Manta, Ecuador in about 730 m depth by USFC Albatross. A very rarely seen species most likely due to the very deep depths it lives in, while in the natural habitat it is probably not uncommon. <br /> <br /> The shell always carries a strong spiral keel bearing numerous nodules on the periphery, while the more posterior keel near the suture is weaker and may or may not carry beads. The shell itself is pearly white, while the periostracum is greenish and has a silky sheen. Typical shell height around 60 mm, very large specimens may reach 80 mm. Originally described in the genus Turcicula, that genus is now considered a junior synonym of Lischkeia (in Turcicidae) and it was moved to Bathybembix in Calliotropidae. It was named after Colonel Marshall McDonald, who led the USFC Albatross expedition when the holotype was collected.
Fusilaria garciai Snyder, 2013<br /> FASCIOLARIIDAE<br /> -200 m, Taken in fish trap, Off Cabo Camarón, Gracias a Dios, Honduras, 183.2 mm <br /> <br /> A large and elegant fasciolariid so far only known from Honduras, the "García's Spindle" was so unusual that a new genus was described to house it. A unique feature among fasciolariids is that there are both interrupted and continuous lirae inside the outer lip, combined with the sharp columaellar folds which are usually two to three in number (though a few additional, much weaker ones may also be present). So far it appears to be a very rare species, with virtually all specimens have been collected as crabbed empty shells from traps set at about 200 m depth. No information is available on its diet, but it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animal like other fasciolariids. Typical shell length around 160 mm, very large specimens may approach 200 mm. <br /> <br /> This species was first discovered by the American linguist and conchologist Emilio Fabian García of Lafayette, Louisiana who has described many new species of gastropods especially from Gulf of Mexico and Caribbean Sea. García collected the type series from a lobster trap off Honduras, which were all crabbed, and donated two specimens to Academ of Natural Sciences of Drexel University, Philadelphia, U.S.A.; this species was thus named in his honour.
Sveltia centrota (Dall, 1896)<br /> CANCELLARIIDAE<br /> -120 m (-400 ft.), Dredged, Off northwest of Isla Danzante, Gulf of California, Mexico, 1970's, 24.3 mm <br /> <br /> Characterised by a single row of long spines on the shoulder, the "Spiny Nutmeg" is a unique cancellariid ranging from Mexico to Pacific Panama with records also from the Galápagos Islands, Ecuador; the type locality is Cocos Island, Costa Rica. Each whorl typically bears 8-10 more or less evenly spaced varices with sharp, slightly recurved spines. It is a rarely seen species, usually trawled or dredged from around 100-200 m deep on soft bottoms. Though its diet is unknown, it is likely a suctorial feeder on the body fluid of other animals like most cancellariids. Typical shell length aroud 25 mm, very large specimens may reach 35 mm. <br /> <br /> It is most similar to Sveltia gladiator (Petit, 1976) from the Galápagos Islands, but can be differentiated as S. gladiator is much larger (typical shell length 45 mm and reaching 55 mm) and also exhibits multiple spines on each varix. The shell of S. gladiator is semi-transparent and less solid than that of S. centrota. Other similar species include Sveltia yoyottei Petit & Harasewych, 2011 from around Guadeloupe which has much shorter spines and also smaller shells (typical shell length 10 mm, large specimens reach 15 mm); and Sveltia lyrata (Brocchi, 1814) from off western Africa which has a much taller spire and shorter spines.
Conus dusaveli (Adams, 1872)<br /> CONIDAE<br /> -80~100 m, By tangle net, Tinina, Balut Island, Davao Occidental, Philippines, 74.2 mm <br /> <br /> The "Du Savel's Cone" is an extremely illustrous classic rarity among the conids, with an intriguing history. The holotype was owned by a Mr Du Savel, its namesake, when it was described in 1872 and supposedly came ex pisces (i.e. from the stomach of a fish) off Mauritius. It remained elusive and one of the greatest rarity among cones as no other specimen was found, and the holotype exchanged hands several times for high prices. Unsurprisingly it made into S. Peter Dance's 50 "Rare Shells" (1969), but shortly after that in 1972 two cone shells dredged off Okinawa, Japan in the National Museum of Tokyo was revealed to be this species. Then the first dive collected specimens were collected also in Okinawa in the late 1970s, and by end of the 1980s specimens began turning up from the deep-water tangle nets of Philippines. Today it is only uncommon, and its distribution centre is from Philippines to Okinawa, Japan; although records also exist from as far as New Caledonia. The holotype which was unique for exactly 100 years after description, and currently resides in the Melvill-Tomlin Collection in the National Museum of Wales; the orignially stated type locality of Mauritius is likely erroneous. It is a carnivorous gastropod that hunts fish by injecting poison with its toxoglossate radula, and inhabits sandy bottoms of moderate depths around -50~250 m deep. Very variable in colouration and pattern and less so in form; typical shell length around 75 mm but very large specimens can exceed 90 mm.
Homalocantha dovpeledi Houart, 1982<br /> MURICIDAE<br /> -30 m, SCUBA dived, Taken on coral covered by sea anemones, Red Sea, Eilat, Israel, 2005/viii, 53.6 mm <br /> <br /> Endemic to the Red Sea, the "Dov Peled's Murex" is characterised by a brownish shell with flat spines that bifurcate at the distal end. A rarely seen species, likely partly due to its restricted distribution and the fact that the shell is usually completely overgrown, making it very challenging to spot. The shell is easily recognisable but specimens do vary considerably in terms of the colouration and spine development. Vast majority of shells are orange-tan in colour, though they can range from whitish to very dark brown. A carnivorous and predatory species feeding on other invertebrate animals, it inhabits hard bottoms around reefs in shallow depths betweeen about -10~50 m. Typical shell length around 50 mm, very large specimens may reach 65 mm. It was named after Dov Peled of Tivon, Israel, who was a prominent shell collector and dealer for Red Sea species. Peled collected the type material for a number of species between eastern Africa and Red Sea, and as a result a few species including this one were named after him.
Buccinum clarki (Kantor & Harasewych, 1998)<br /> BUCCINIDAE<br /> -205 m, Trawled on black sand, North of Atka Island, Alaska, U.S.A., Leg. Roger Clark, 1997/vii, 55.4 mm <br /> <br /> The "Clark's Whelk" is a bathyal buccinid endemic to the Aleutian Islands, where it inhabits soft bottoms between about 150~500 m deep. The shell is ornamented by numerous fine spiral cords and lacks prominent axial sculpture; the operculum is unusual in being small, triangular, and having a subcentral nucleus. This operculum morphology, together with it having a very large osphradium, led to its original description in genus Bathybuccinum. However, a recent phylogenetic study synonymised Bathybuccinum with Buccinum, and therefore it is now placed in that genus. A carnivorous and predatory gastropod, it presumably feeds on other invertebrate animals. Its restricted range in the Aleutian Islands means it is a rather rarely seen species. Typical shell length around 45 mm, very large specimens may exceed 65 mm. Young specimens tend to exhibit stronger peripheral keels on the shell, which becomes much weaker on the body whorl of larger specimens. The species name was dedicated to the American conchologist Roger N. Clark who participated in many surveys around the Aleutian Islands and collected the type material.
Halicardia flexuosa (Verrill & Smith, 1881)<br /> VERTICORDIIDAE<br /> -1000 m, Trawled, Off Namibia, 48.0 mm <br /> <br /> A deep-sea bivalve with very unusual shell morphology characterised by strong 'folds', the "Flexed Verticord" is a large verticordiid with a very wide distribution throughout the Atlantic Ocean. Published records indicate scattered specimens have been collected from localities spanning off Massachusetts, U.S.A. (type locality) to Iceland to Scotland to Bay of Biscay to Namibia to even the western coast of South Africa. These records tally up to only about 10 live-taken specimens and a few dozens of dead and disarticulated single valves, making it an extremely rare species. Live individuals have been taken from deep waters between approximately -500~2000 m, whereas empty valves have been collected from a wider bathymetric range between about -200~2500 m. <br /> <br /> The shell always carries three major 'folds', the median one by far the strongest; this is a unique feature that separates this species from other named congeners. The overall development of these cords vary from specimen to specimen and influences the overall shell form, where those with stronger cords exhibit a higher shell shape with more angular margins. As in other Halicardia species, numerous fine radial striae are also present on the shell but do not influence the overall shell form. A carnivorous bivalve, it captures small prey (mainly crustaceans) using a strong suction current enabled by anatomical adaptations such as the gills being modified into mucsular septa. Verticordiids are also capable of using adhesive fluid on the siphons to help capture prey, and have evolved muscular oesophagus and muscular stomach to crush them. <br /> <br /> Typical shell height around 30 mm, very large specimens can exceed 45 mm. It is the type species of the genus Halicardia, the name of which refers to the shell form that appears to be heart-shaped when viewed from the side. The specific epithet 'flexuosa' was named in reference to the three folds, or 'flexes' on the shell surface.
Lotoria armata (Sowerby III, 1897)<br /> CYMATIIDAE<br /> Dived in shallow water, Northern Queensland, Australia, 64.0 mm <br /> <br /> Characterised by a spiny shell with numerous short spines on the varices and very strong intervarical nodes, the highly distinctive "Armed Triton" is perhaps the rarest and most sought-after cymatiid of all. This species was made famous when it was rediscovered by Russ Webb of the Oregon Shell Club who found a live specimen in Fiji in 1996 and then posted photos on the (online) Hawaiian Shell News for identification in 1997. Other collectors including Harry G. Lee and Betty Jean Piech correctly identified the species, and followed up with comments noting that only seven specimens were known at the time and that it took exactly a century since description for a specimen to be collected with detailed collecting data. Even today it is only known from not much more than a couple dozens of specimens despite inhabiting shallow waters from just a couple of meters down to about 20 m deep, the reasons behind its rarity is unclear. <br /> <br /> The holotype was a specimen with unknown locality, though Sowerby III speculated that it might have come from the Marquesas Islands since its collector B.C. Thomas had collected most of his material in French Polynesia. All later specimens collected with reliable data, however, were from an area of the South Pacific much further to the west including Vanuatu, New Caledonia, Fiji, and Queensland of Australia; indicating Sowerby III's speculation was likely incorrect. Live specimens have been collected on top of coral reefs or on rocky slopes near reefs, and at least one has been found beached after storm. It is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals like typical cymatiids. Though always instantly recognisable, it is quite variable in the extent of spine development and also the base colour of the shell can range from light brown to dark red. Typical shell length around 60 mm, the largest specimens can exceed 80 mm. Originally described in Lotorium (now synonym of Cymatium), it was once moved to Ranularia based on its long anterior siphonal canal but later transferred to Lotoria largely on the basis of having an operculum with an antetior terminal nucleus rather than a subcentral one typical of Ranularia.
Galeodea maccamleyi Ponder, 1983<br /> CASSIDAE<br /> -50~100 m, Off Cape Moreton, Queensland, Australia, 34.1 mm <br /> <br /> An unusually small species for its genus with a typical shell length around 30 mm and the largest specimens reaching only 40 mm, the "McCamley's Bonnet" is a cassid endemic to southern Queensland, Australia, ranging approximately between Swain Reefs and the Capricorn Channel. Its prickly shell is characterised by four evenly spaced spiral rows of whitish nodules on a pale or darkish brown background, as well as a dark protoconch (most Galeodea species have white protoconchs). Furthermore, the fine but strong, numerous spiral threads distributed across the entire shell surface even on the early teleoconch whorls also help separate it from other congeners. <br /> <br /> A carnivorous gastropod presumably feeding on echinoderms like other cassids, it inhabits soft bottoms of moderate depths between about -100~400 m deep. It is a rare species, majority of specimens have been collected dead as empty shells; live-taken specimens retaining a striking colour pattern are seldom seen. The first known specimens were collected by the Queensland shell collectors F. McCamley and Jim Whittle who provided the material to the Australian Museum for study and description. It was named after McCamley, who donated the holotype specimen plus two paratypes to the museum upon the description of this species.
Volutoconus bednalli (Brazier, 1878) <br /> VOLUTIDAE<br /> -450m, Trawled on sandy reef in the Arafura Sea, Off Indonesia, 1995, 148.2 mm <br /> <br /> The "Bednall's Volute" is a classic rarity among the volutes and one of the most striking species characterised by a shell with a unique and extremely attractive chocolate-laced pattern. One of S. Peter Dance's 50 "Rare Shells" (1969); it was described from a shell that belonged to the Australian collector William T. Bednall, its namesake. This shell remained the sole known specimen until 1893, and by early 1900s more specimens had appeared. An anecdote tells that divers used to exchange each specimen caught with a bottle of brandy. <br /> <br /> Today it is known to be a moderately rare species ranging from northern Australia (in the Arafura Sea and the Timor Sea) to eastern Indonesia. It is a predatory gastropod inhabiting shallow to moderately deep water around -50~150m deep, and usually lives on sandy bottoms. Typical shell length around 110 mm, although extreme giants may exceed 165 mm. The spire height varies greatly and accounts for much of the size variation. The extent of surface sculpture on the shell may also vary from rather smooth to strong and wrinkle-like; and the base colouration ranges between pure white and yellowish white.
Eofavartia tatei (Verco, 1895)<br /> MURICIDAE<br /> -38 m, Dived, Among seaweed on coarse sand, Off Cape Le Grand, Esperance, Western Australia, Australia, 1999, 29.4 mm <br /> <br /> An unmistakable muricid with a multifaceted-looking shell, the "Tate's Murex" is endemic to the south coast of Australia and ranging roughly between Esperance, Western Australia and Backstairs Passage, South Australia. Originally described in the genus Murex, it was later moved to Murexiella (now synonymised with Favartia) where it stayed for decades. In 2013 it was transferred again to Subpterynotus based on fine details of the varical ornamentation, despite typical Subpterynotus species were only known from fossils outside the Indo-West Pacific all having three varices per whorl. Recently in 2020, it was instead attributed to Eofavartia as a relict species of that genus which is also known from Pliocene fossils in Australia, noting that it lacks two key characters of Subpterynotus -- trivaricate shell and intervarical ribs. Currently it is considered to be the only extant species of the genus whose fossil record extends back to Palaeogene. <br /> <br /> A carnivorous and predatory gastropod probably feeding on other invertebrate animals, it inhabits rather shallow waters between 20~50 m deep and is a rarely seen species. Though it cannot be confused with other living muricids it is somewhat variable in the development of the final varix, and the shell colouration can range between whitish to dark brown. Typical shell length around 25 mm, very large specimens may exceed 35 mm. It was named in honour of Ralph Tate (1840-1901), who worked as a professor of geology at the University of Adelaide but also made significant contributions to both invertebrate paleontology and botany.
Pyrulofusus deformis (Reeve, 1847)<br /> BUCCINIDAE<br /> -150~250 m, Trawled, Bristol Bay, Bering Sea, Alaska, U.S.A., 1978/viii, 98.5 mm <br /> <br /> The "Sinistral Arctic Whelk" is a cold-water buccinid whelk notable for producing a normally sinistral shell. Though perhaps best known from Sea of Okhotsk and Bering Sea, its distribution extends to the Arctic Ocean where it has a nearly circumpolar range -- the type locality is actually Spitsbergen in northern Norway. A carnivorous gastropod, it inhabits a wide-range of substrates from rocky to muddy to sandy bottoms and across a rather broad bathymetric range between about 10~300 m deep. Like other Pyrulofusus species it goes through direct development and hatches as crawling juveniles over 1.5 cm in shell length, from large eggs about 2.5 cm in diameter. An egg collected from Alaska was found to contain three hatchlings, almost completely filling up the available space. Though supposedly not uncommon in its natural habitat, the limited availability of material from its range makes it a moderately rarely seen species. Typical shell length around 100 mm but this is greatly variable, with mature specimens ranging between around 50~150 mm. Both the shell surface colouration and the colour inside the aperture are rather variable, from whitish yellow to dark chestnut to even reddish violet. <br /> <br /> It is often confused with its another sinistral species in the same genus, the rarer Pyrulofusus harpa (Mörch, 1858). The two species are actually not difficult to distinguish, as P. harpa carries coarse, regular, strongly raised spiral cords across the entire shell that is lacking in P. deformis. Furthermore, P. harpa has a much narrower distribution range, being only found off Alaska including the Aleutian Islands. Though there are some records of supposedly P. harpa from Sea of Okhotsk to off Kamchatka Peninsula, extensive research samplings have not recovered a single specimen reliably localised in this area and these records therefore most likely represent misidentified specimens of P. deformis.
Priotrochatella constellata (Morelet, 1847)<br /> HELICINIDAE<br /> On limestone, Sierra de Casas, Isla de la Juventud (Isle of Pines), Cuba, 1994/ix, 12.6 mm<br /> <br /> Endemic to Sierra de Casas, a mountain range on Isla de la Juventud (also known as Isle of Pines) of Cuba, Priotrochatella constellata is among the world's most eye-catching landsnails characterised by numerous delicate blade-like varices on a strongly carinated shell with an offset coiling in the last two whorls. The base shell colouration is white to very light yellow, overlaid by patches of darker colour that can range from yellow to strawberry red. These patches are distributed rather regularly on earlier whorls, but become increasingly sparse and irregular on the later ones. The shell is otherwise little-varied among individuals; in fully mature individuals the lip is thickened. Typical shell width around 10 mm, very large specimens may approach 15 mm. As is typical in helicinids it possesses a kidney-shaped operculum, which is thinly calcified with a papillose surface. <br /> <br /> A herbivorous grazer, it lives on limestone and feeds on the algae and lichens that grow on the same rocks. Though supposedly common in its local habitat, due to its restricted range in a politically difficult area it is a rarely collected species. In the recent years, it has become increasingly threatened by quarrying activities in and near its habitat. The genus Priotrochatella itself is restricted to Isla de la Juventu, Cuba and Jamaica; among all three known species P. constellata exhibits the most elaboratly ornamented shell. The coiling offset seen in the penultimate and final whorl in P. constellata is unique in Priotrochatella, and hence it cannot be confused with other species.
Barycypraea fultoni fultoni (Sowerby III, 1903) <br /> CYPRAEIDAE<br /> -97~105 m, Dredged on low-profile reef covered in sponge, Off Trafalgar, KwaZulu-Natal, South Africa, 59.6 mm <br /> <br /> A truly unique cypraeid species, the "Fulton's Cowrie" is one of the most famed and desirable cowries of all. Today its known range is from East London, South Africa to Mozambique, with a slight disjunction between the two countries where there are virtually no records. First discovered from the digestive tract of fishes (termed "ex pisce", mostly from the "Black Musselcracker" Cymatoceps nasutus (Castelnau, 1861)) off Natal, South Africa, for years this remained the only way of obtaining this species. Only after 1987 live and fresh-dead specimens have begun to surface through deep-diving and dredging in eastern South Africa, although these remained extremely rare. More recently, Russian trawlers hit the 'jackpot' when they discovered a large number of this species off Mozambique, causing the market price to drop significantly around the 1990s. <br /> <br /> Although sharing the general characteristics with the South African ones, individuals from Mozambique were larger, more inflated, and had more numerous teeth especially on the columellar side. Specimens varied greatly in form, and rarely an individual may be found with callous so extensive that the shell appears triangular from dorsal view. This triangular form of the Mozambique population was described as B. fultoni amorimi (Raybaudi, 1989). The more common, inflated and globular specimens found in Mozambique was initially described as a separate subspecies B. fultoni massieri (Lorenz, 1991) two years later, but after the investigation of a large series with numerous intergrades this is now synonymised with B. f. amorimi. The two subspecies recognised today are therefore segregated geographically: all specimens from South Africa are B. fultoni fultoni (shown here) and all specimens from Mozambique are B. fultoni amorimi. <br /> <br /> One of the 50 "Rare Shells" selected by S. Peter Dance (1969), trawl supplies from Mozambique has become scarce nowadays and thus this species has become very rare again overall, especially with its ever-increasing popularity and demand. The nominal subspecies from South Africa is still rare even as dead collected shells, and extremely rare as always in live-collected condition; the Mozambican subspecies is only moderately rare even when in good condition, though the triangular form is extremely rare. The surface of B. f. amorimi is typically naturally covered with fine granules, causing the surface to appear slightly dull; the surface of B. f. fultoni almost always appears naturally polished when alive. As the triangular form is much rarer and commanded high prices, the informal form name 'triangularis' has grew popular for differentiating strongly calloused specimens of B. f. amorimi, while using 'mozambicana' for typical, more slender specimens. As for the nominal South African subspecies, the form name 'miniatra' has been used to describe remarkably small, dark specimens (usually around 50 mm or less in shell length). The nominal subspecies is now usually collected by deep dredges, with occasional specimens taken by very deep diving. <br /> <br /> In addition to the variations in shell form mentioned above (very variable within each population), the spotting of the sides and the base are also highly variable. The mesmerising pattern on the dorsum is yet another source of variation, with those forming a cross-like pattern known as the "Maltese Cross" most highly prized among collectors. A carnivorous grazer feeding exclusively on sponges, it inhabits moderately deep waters around -60~150 m and live on flat bottoms with rubble and sponges. Typical shell length is around 60 mm for the nominal subspecies which may attain 75 mm in the largest specimens, while the subspecies B. f. amorimi averages at about 70 mm and can reach even 85 mm. The name 'fultoni' was given in honour of the British dealer Hugh C. Fulton, 'amorimi' was named for the Portuguese dealer Manuel Amorim, and 'massieri' was named after the South African conchologist and dealer Werner Massier.
Callipara bullatiana Weaver & duPont, 1967<br /> VOLUTIDAE<br /> -20 m, Dived on sand, Algoa Bay, Cape Province, South Africa, 1995, 55.2 mm <br /> <br /> The "Bullate Volute" is a uniquely shaped volutid endemic to South Africa, instantly recognisable from its short-spired, cylindrical shell lackin in shoulder nodules. Ranging from central Algulhas Bank to around Port Elizabeth, it inhabits shallow to moderate depths between around -10~50 m and is a carnivorous gastropod mainly feeding on other invertebrate animals. <br /> <br /> Initially, it was described as Voluta bullata Swainson, 1829 which was unfortunately a junior homonym of Voluta bullata Born, 1778 (now Bullata bullata (Born, 1778), a brazilian marginellid) which led to the replacement name Callipara bullatiana Weaver & du Pont, 1967. The genus Callipara was originally established to house just this species due to its strange shell shape, but later it became clear that the soft parts of this species is in fact very similar to other African volutids such as Callipara africana (Reeve, 1856) which were then housed in Festilyria. The shell structure and colouration are also in fact similar to C. africana, currently thought to be its closest living relative. As a result, Festilyria was synonymised with Callipara and all species in that genus were moved to Callipara. The reason behind C. bullatiana evolving an unusual shell shape, resembling and often compared with the Australian enigma Lyria laseroni (Iredale, 1937), which is very different from all of its congeners, remains unclear. <br /> <br /> Though clearly not a rare species in its natural environment due to beached empty shells being quite common, live animals have been surprisingly scarcely seen by divers and live-taken specimens remain rare. Generally stable in shell morphology with individuals usually differing only in the development of the shell pattern, though it is quite variable in size. The average shell length of mature specimens is around 55 mm, but the extremes can be as small as 40 mm and as large as 80 mm.
Paradusta barclayi (Reeve, 1857)<br /> CYPRAEIDAE<br /> -85~90 m, Dredged, Off Trafalgar, KwaZulu-Natal, South Africa, 28.6 mm <br /> <br /> A classic rarity from Indian Ocean, the "Barclay's Cowrie" is characterised by extremely strong, swollen teeth that extends across the lip and a dorsum densely dotted by brown speckles. Though best known from South Africa where the vast majority of specimens have been collected, its range extends northwards to Mozambique on continental Africa and has also been recorded from both Mauritius and the Chagos Archipelago. Once an exceedingly rare species, more recently deep-water dredges in South Africa has yielded some specimens, making it only moderately rare. Most specimens are however collected as empty shells and/or with drill holes and chips; intact live-taken specimens remain scarce. <br /> <br /> A spongivorous grazer like many other cypraeids, it inhabits moderate depths between about -50~200 m on low profile reefs where it is found among rubble and sponges. Though the distinctive teeth makes it unmistakable among living cowries, it is rather variable in shell form and the darkness of the dorsal patterning. Typical shell length around 25 mm, very large specimens may approach 35 mm. It was named in honour of the British conchologist Sir David William Barclay (1804-1888) who spent almost two decades living in Mauritius and was responsible for the discovery of many Indian Ocean mollusc species. <br /> <br /> Recently, a morphologically distinct population characterised by weaker but more numerous teeth and coarser dorsal patterning was found off northeastern Sumatra Island of Indonesia and given the subspecies name P. b. sumatrensis Lorenz, 2017. Currently only known from a few specimens, further data on this population may show that it should be treated as a distinct species in its own right.
Tonna hawaiiensis Vos, 2007<br /> TONNIDAE<br /> -200~250 m, By lobster trap, Off Oahu, Hawaii, U.S.A., 1980/vi, 139.2 mm <br /> <br /> As its name suggests, the "Hawaiian Black-Mouthed Tun" is a tonnid endemic to the Hawaiian Islands where it is known from a rather wide bathymetric range from about -5~200 m deep. Although locally common when taking into account crabbed and beached shells, live-taken specimens are rare; it appears to be more common in the Leeward Islands than the Windward Islands. The live animal is entirely black in colouration, and is presumably an active carnivorous and predatory gastropod feeding on echinoderms. Due to the remarkable blackish colouration around the aperture it has been long confused with Tonna melanostoma (Jay, 1839) from the Western Pacific, the only other species in the genus Tonna that shares this characteristic, with the Hawaiian specimens considered a form of T. melanostoma. <br /> <br /> At last, after examining many specimens of both species carefully side-by-side, the tonnid expert Chris Vos was able to show clearly that the two are separate species which led to the description of T. hawaiiensis. The two species differ most clearly in the spiral sculpture, with T. hawaiiensis having rounded, crested, and raised cords similar to T. variegata (Lamarck, 1822) and most interspaces lack obvious secondary cords, whereas T. melanostoma has broad, flat main cords with well-defined secondary cords between them, reminiscent of T. chinensis (Dillwyn, 1817). Although T. hawaiiensis appears to be greatly variable in size with a typical shell length around 100 mm but the largest specimen confirmed exceeds 200 mm, generally speaking it is smaller and more elongate in shell form than T. melanostoma (typical shell length around 200 mm, largest specimens exceed 300 mm). Even in the largest specimens of T. hawaiiensis the inside of the aperture is not fully darkened like that of adult T. melanostoma shells. Often the shell of T. hawaiiensis carry a pattern with randomly placed white patches, which is lacking in T. melanostoma. In young T. melanostoma the colouration of the main cords usually alternate between whitish and brownish (a feature lost in adults), but this is not seen in T. hawaiiensis of a similar size.
Bullata bullata (Born, 1778)<br /> MARGINELLIDAE<br /> -50~60 m, By lobster traps, Off Guarapari, Espirito Santo, Brazi, 2019/ii, 92.3 mm <br /> <br /> A marginellid with an unusually broad range of mature adult sizes, the "Bubble Margin" averages at around 60 mm in shell length but can be from anywhere between about 35~100 mm. Recently, two species previously considered to be the largest species of Marginellidae -- Marginellona gigas (von Martens, 1904) and Afrivoluta pringlei Tomlin, 1947 -- were shown to belong to a separate lineage outside of Marginellidae and thus moved to Marginellonidae (previously thought to be a subfamily under Marginellidae). This means B. bullata now grows to be the largest marginellid species in the world. Endemic to Brazil and inhabiting sandy bottoms of shallow to moderate depths between about -5~50 m, it is a carnivorous and predatory gastropod feeding on invertebrate animals though the exact diet is unclear. <br /> <br /> A common species, although most specimens have been collected from octopus dens with drill holes and live-taken individuals are actually uncommon. Vast majority of specimens have been taken in either Espirito Santo or Bahia states of Brazil. The mantle and head-foot share a much more extravagant colour pattern consisting of fine, intricate zebra patterns; the mantle also possesses numerous thick papillae. It is not a variable species in terms of shell characters except size and clarity and thickness of the spiral bands, but over the years a number of synonymous names have been proposed, such as Marginella bellangeri Kiener, 1834 and Marginella glauca Fischer, 1807.
Morum macdonaldi Emerson, 1981<br /> HARPIDAE<br /> -20~30 m, Dived on coral sand, Oceanside, Kwajalein, Marshall Islands, 1992/x, 16.7 mm <br /> <br /> The "MacDonald's Morum" is a small-sized harpid characterised by a regular, coarsely cancellate shell sculpture with the spiral ribs almost as strong as the axials, and a narrow, pustulated parietal shield confined to the columella wall. First recognised as new by a shell collector named D. J. MacDonald who collected about a dozen specimens on Kwajalein Atoll, Marshall Islands, the specimens were forwarded to the shell dealer Robert William Morrison (1929-2012), and then to the malacologist Dr William K. Emerson (1925-2016) based at the American Museum of Natural History. Emerson later described the species, naming it after MacDonald. Later, it was also recorded from Tuamotu Archipelago, French Polynesia, as well as the Caroline Islands, Micronesia. Partly due to its limited distribution on small Pacific islands and its minute body size, it has remained a very rarely seen species from the time of its discovery until today. <br /> <br /> A carnivorous and predatory gastropod most likely feeding on small crustaceans like other Morum species, it inhabits sand to rubble bottoms of shallow waters around -10~30 m deep. Typical shell length around 15 mm, very large specimens may reach 20 mm. Morum janae Monsecour & Lorenz, 2011 appears to have been described based on a beachworn empty shell of M. macdonaldi from Tuamotus, and should be treated as a junior synonym unless convincing evidence can be presented showing that the Tuamotus population is a distinct evolutionary lineage from the Marshall Islands population.
Neopetraeus binneyanus (Pfeiffer, 1857)<br /> BULIMULIDAE<br /> +1260 m, Collected on bush, Pataz, Pataz Province, La Libertad Region, Peru, 21.4 mm <br /> <br /> Immediately recognisable by its unusual and distinctive shell shape with a very strong medial keel across the whorls, Neopetraeus binneyanus is a bulimulid landsnail endemic to La Libertaz Region of Peru. It inhabits highland limestone areas around +1200 m in elevation, where it has been collected on rocks, bushes, trees, and cacti. Though the exact diet is unknown, it presumably is a grazer of plant and algae. The development of the keel can vary somewhat among individuals, and similarly the spire height is also rather variable. Vast majority of specimens are uniformly ivory to yellowish in shell colouration, but some specimens carry brown axial stripes. Typical shell length around 20 mm, very large specimens can approach 30 mm. It occurs together with the congener N. arboriferus paucistrigatus (Weyrauch, 1967) which has a smooth shell lacking in carination, and some individuals appear to be intergrades between the two. Whether these specimens represent hybrids or if the two taxa involved are actually just two names given to morphological extremes of the same evolutionary lineage require further investigation.
Drupa speciosa (Dunker, 1867)<br /> MURICIDAE<br /> -15~20 m, Dived under coral at night, Taiohae Beach, Nuku Hiva, Marquesas, 32.5 mm <br /> <br /> Characterised by a deep magenta aperture fringed by white, the “Splendid Drupe” is a shallow water muricid endemic to island groups within a small area of the South Pacific: Tuamotus Islands, Marquesas Islands, and Pitcairn Islands. Inhabiting hard substrates of shallow waters from low intertidal down to about 30 m deep, it is a carnivorous and predatory gastropod. Typical shell length around 30 mm, but very large specimens sometimes exceed even 55 mm. Although its specific diet is not known, its sister species Drupa rubusidaeus Röding, 1798 feeds on polychaete worms and it likely does the same. <br /> <br /> Despite being only uncommon locally, it is a rather rarely seen species due to its restricted range and also confusion with the morphologically similar D. rubusidaeus. These two species have largely overlapping distribution ranges due to D. rubusidaeus being a very widely distributed species across the warm Indo-West-Central Pacific, genetic analyses agree that they are two distinct lineages that diverged around six million years ago and likely speciated through allopatric speciation. Though superficially similar, the two species can be separated with good confidence by observing the aperture of mature specimens through the following two features: 1) D. speciosa has an inner ring of strong magenta always fringed by a white rim, whereas D. rubusidaeus typically exhibits a yellow to orange rim; 2) The white teeth on both the outer lip and columellar are stronger in D. speciosa leading them to stand out very clearly from the magenta ring, whereas in D. rubusidaeus the teeth are smaller and less crisp in appearance.
Calliotropis chunfuleei Chino, 2014<br /> CALLIOTROPIDAE<br /> -300~400 m, Taken on sand by shrimp trawler, Off Pratas Islands, South China Sea, 32.0 mm <br /> <br /> The "Chunfu Lee's Toothed Top" is a large calliotropid with an unmistakable shell morphology, with a pearly-white, depressed trochoid shape and ornamented by two very strong, nodulous peripheral keels and a few weaker ones on the base. Due to these keels the shape of the aperture appears twisted and is very striking, reinforced by the presence of a wide lateral extension of the inner lip which almost completely covers the wide umbilicus in mature adult specimens. Most of the shell lacks significant axial ribbing, except the narrow area between and around the two peripheral keels, where numerous intricate axial lamellae are present. <br /> <br /> Only known from soft bottoms of rather deep waters between -200~600 m off Pratas Islands in the South China Sea, its restricted and deep habitat may explain why such a remarkable species was not discovered and named until the early 2010's. Its description was based on three shells obtained by Chunfu Lee, a Taiwanese conchologist and its namesake, who forwarded them to the Japanese conchologist Mitsuo Chino for examination and description. Since then it has remained a very rare species, most specimens collected were empty shells inhabited by hermit crabs and often with black stains on the shell; live-taken specimens take some luck to find. Although its specific diet is not known, it is probably a deposit-feeding species. A little-varied species, though individuals may vary in the number of clearly visible spiral ridges on the base. Typical shell width around 25 mm, very large specimens may reach 35 mm.
Rostellariella lorenzi Morrison, 2005<br /> ROSTELLARIIDAE<br /> -200~400 m, Trawled on sand and mud, Arafura Sea north off Darwin, Northern Territory, Australia, 2000's, 94.5 mm <br /> <br /> Characterised by a nearly straight-sided spire carrying numerous weak spiral sculpture and a reddish-brown, flammule-like axial pattern that is unusual for the family, the "Lorenz's Tibia" is a rostellariid known exclusively from the Arafura Sea. An extremely rare species, it was first described from several empty shells trawled by Indonesian fishermen. Only a few specimens appeared around the time of its description, likely from the same sampling event, and then virtually none have been collected since. The known specimens have been trawled on soft bottoms of rather deep waters between 200~400 m deep, but likely no live-taken specimens have been collected. Though the exact diet of this species is unclear, it is probably a herbivorous to detritivorous gastropod feeding on algae and other organic material in the detritus. Typical shell length around 90 mm, very large specimens may exceed 100 mm. <br /> <br /> The supposedly Pliocene fossil species Rostellariella perlonga (Koperberg, 1931) from Timor has been noted to potentially represent the same species and may be a senior synonym, but no known specimens of R. perlonga retain a mature aperture and this cannot be confirmed with certainty as of yet. The recent Rostellariella barbieri Morrison, 2008 described from the Philippines is almost identical to R. lorenzi except it carries four dentitions on the outer lip instead of five, a character known to vary in other rostellariellid species. As such, it has been suggested that R. barbieri is likely just a junior synonym representing a Philippines population of R. lorenzi. The specific epithet 'lorenzi' honours Felix Lorenz, a well-known shell collector and dealer best known for his extensive expertise in cowries and allied-cowries.
Bursa luteostoma (Pease, 1861)<br /> BURSIDAE<br /> -80~120 m, By lobster trap, Mano Reef, Hawaiian Islands, U.S.A., 1994, 62.3 mm <br /> <br /> Endemic to the Hawaiian Archipelago, the "Yellow-Mouthed Frog Shell" is a bursid snail with a rather tall spire carrying strong nodules and a yellow aperture. It is among the rarest bursid species in the world, and is a greatly sought-after species by collectors; most specimens have been taken crabbed in loster traps and live-taken specimens are exceedingly rare. It has been found from very shallow waters less than 1 m deep down to about 100 m depth, and is thought to be a predatory and carnivorous gastropod feeding on other invertebrate animals. Typical shell length around 60 mm, very large specimens may exceed 85 mm. <br /> <br /> It is very similar to the common Bursa bufonia (Gmelin, 1791) which is widely distributed in the Indo-West Pacific. Typical specimens of B. luteostoma (shown) exhibit a narrower and taller spire ornamented with deeply sculptured, rugged nodules and can be distinguished relatively easily from typical B. bufonia. Some specimens attributed to B. luteostoma, mostly from shallower depths, exhibit weaker sculpture and broader spire than normal, making them difficult to distinguish from B. bufonaria. Different authors have expressed varying opinions on these broad B. luteostoma individuals, including 1) they are variations within B. luteostoma and B. bufonia does not occur in Hawaii, 2) they are B. bofonia and both species co-occur in Hawaii, and 3) B. luteostoma is a regional form and thus a junior synonym of B. bufonia. Though this debate is not settled completely, recent authors generally agree that at least the typical form of B. luteostoma is distinct from B. bufonia. <br /> <br /> The shell colouration of B. luteostoma is somewhat variable, the base colour can be light yellow to orange-tan and the amount of dark brown speckles vary greatly among individuals. The aperture is yellowish in vast majority of specimens, though it may also rarely exhibit whitish aperture with only a faint hint of yellow.
Ancillista fernandesi Kilburn & Jenner, 1977<br /> ANCILLARIIDAE<br /> -75~100 m, Trawled, Among small rocks on sandy-muddy bottom, Off Quissico, Inhambane, Mozambique, 2003, 66.4 mm <br /> <br /> A white shell strikingly enamelled by chocolate callous characterises the "Fernandes' Ancilla", an ancillariid known exclusively from southern Mozambique. It is an unusual member of the genus in terms of shell morphology, because in adults the spire is very heavily overlaid by two layers of callous that completely conceals the suture. The first layer of callous is yellowish brown and lighter in colouration, covering parts of the body whorl in addition to the spire; the second layer is dark reddish brown and is concentrated on the spire. These features mean it cannot be confused with any other congeners which typically only exhibit thin callous. Though a little-varied species, the extent of callous coverage on the body whorl varies somewhat among individuals. <br /> <br /> Originally described from three shells collected ex pisce from fish stomach between Inhaca Island and Zavora by the prominent Mozambique-born Portuguese collector and dealer César Pasos Fernandes (1930-2007), who contributed to our understanding of malacological diversity of Mozambique and the Cape Verde Islands by discovering numerous new species. This species was named after Fernandes in recognition of his efforts in collecting the types and offering them to KwaZulu-Natal Museum for study and description. Today it remains an extremely rare species, very few specimens have been collected alive since its description and even dead-taken shells are scarce. Live specimens have been collected on soft bottoms between -50~150 m deep, either by trawl or in traps. Though the diet of this species has not been studied, it is presumably a predatory and scavenging gastropod like other ancillariids. Typical shell length around 60 mm, very large specimens may exceed 85 mm.
Cocculina aurora Chen, Hilário, Rodrigues & Ramirez-Llodra, 2022<br /> COCCULINIDAE<br /> -3883 m, Hans Tore Vent chimney (82°53.8307'N, 6°15.3251'W), Aurora Vent Field, Gakkel Ridge, Central Arctic Ocean, ROV Aurora dive no. 12, 2021/x/08, R/V Kronprins Haakon cruise HACON21: Holotype (NHMUK 20220343), 4.5 mm <br /> <br /> An unusual cocculinid limpet only known from surfaces of dead chimney structures in the Aurora Vent Field, Central Arctic Ocean, Cocculina aurora is currently the only member of its family restricted to hydrothermal vent ecosystems and the second vent-inhabiting member of the family. Located >3880 m deep at a very high latitude of 82°53.83'N, Aurora is the world's northernmost deep-sea vent known so far. As it is under permanent sea ice cover, sampling there was extremely difficult and took multiple cruises with ice breakers before finally specimens could be retrieved. Cocculina aurora is perhaps the most dominant animal found there, occurring at high densities on chimney structures just meters away from high-temperature venting orifices. Like other Arctic vents explored so far, Aurora was devoid of typical large-bodied Atlantic vent fauna like vent shrimps or mussels and instead was mainly colonised by small gastropods and amphipods. <br /> <br /> Molecular phylogeny reconstruction showed that C. aurora evolved from ancestors living on sunken wood. Though this is similar to the only other vent cocculinid Cocculina enigmadonta Chen & Linse, 2020 from Antarctic vents (and also a whale fall), the phylogeny shows clearly that the two species adapted to hydrothermal vents independently. The shell of C. aurora is very high-profiled for the genus and the radula is unique with broad, multi-cuspid rachidian where the outermost lateral is reduced compared to typical cocculinids. This is considered to be an adaptation to grazing on bacterial mat instead of picking up wood pieces -- the major function of massive outer laterals in typical cocculinids. Typical shell length around 4 mm, very large specimens can reach 6.5 mm. The name "aurora" carries triple meaning alluding to Aurora, the goddess of dawn in Roman mythology, the type locality Aurora Vent Field, and the ROV Aurora that collected the type specimens.
Thalassocyon bonus Barnard, 1960<br /> THALASSOCYONIDAE<br /> -1200 m, Dredged, Off Hawke’s Bay, East of North Island, New Zealand, 52.4 mm <br /> <br /> Thalassocyon bonus is an enigmatic deep-water caenogastropod species and certainly one with some history — its familial assignment has undergone a number of dramatic revisions over the years. It was originally described under Cymatiidae in 1960 from South Africa, with the genus Thalassocyon newly established to house this species which clearly did not fit in any known genera. A few years later, T. tui Dell, 1967 was described from off New Zealand; the New Zealand malacologist Alan Beu rectified the family placement to Ficidae based on shell, radula, and periostracum characters. This was unusual as Thalassocyon looks completely different from species of Ficus, the type genus of Ficidae. Neverthelss, a study of its anatomy by the malacologists Anders Warén and Philippe Bouchet followed in 1990, concluding that its placement in Ficidae is likely correct. They also synonymised T. bonus and T. tui, rendering T. tui as junior synonym of T. bonus, since the two only differ in spire height and specimens found off Amsterdam Island, Indian Ocean in-between the two localities also exhibited intermediate spire height. <br /> <br /> The German malacologist Frank Riedel disagreed with this view, however, and described the Amsterdam Island population as new species T. wareni, 2000 while proposing all three populations should be treated as distinct species. The debate of synonymy is still not settled yet with different authors having different opinions, though the other names were listed as synonyms of T. bonus in the comprehensive review of Ficidae later in 2000 by the conchologists Marcel Verhaeghe and Guido Poppe and is the opinion followed here. Back in 1995, Riedel also attempted to elevate the genus to family level, Thalassocyonidae, but was not accepted by other authors at the time. So for many years, this species was considered to be a wonderous singular “outlier” species of Ficidae. <br /> <br /> Everything changed again in 2018, however, when Smithsonian's Ellen Strong and colleagues published the first molecular phylogeny that included this species. Their results rather shockingly placed Thalassocyon as closely related to Personidae, the distorsios, in the superfamily Tonnoidea (i.e., not even in Ficoidea, the superfamily containing Ficidae). Even more surprisingly, Distorsionella, a genus traditionally placed in Personidae and morphologically similar to other personids, actually came out more closely related to Thalassocyon than other personids. Based on these evidence, Strong and colleagues concluded that Thalassocyon must be an unusual genus highly modified from personid-like ancestors, united by features such as a small corneous operculum and very long proboscis that become coiled when retracted. They resurrected Thalassocyonidae to house this genus and also Distorsionella. Interestingly, this actually corrobrates the results of a phylogeny based on morphological data by the Brazilian malacologist Luiz Simone in 2011 which also placed it next to Personidae, indicating anatomical similarities between Thalassocyon and Ficidae are likely superficial. At last, after more than half a Century since its discovery, we might finally know where Thalassocyon bonus stands in the tree of life. <br /> <br /> Inhabiting great depths between about -1000~2700 m and ranging from South Africa to Amsterdam Island to Australia to New Zealand, it is a carnivorous and predatory gastropod whose stomach contents suggest the primary prey to be annelid worms. Though its distinctive shell morphology means it cannot be confused with any other species, it is somewhat variable in terms of spine development and spire height. The shell colour is fawn to reddish brown, with living specimens displaying a purplish colour inside the aperture that fades after death. Mature specimens usually have worn shells that are chalky white in appearance. It is an extremely rarely seen species due to the great depths it inhabits. Typical shell length around 50 mm, very large specimens can exceed even 75 mm.
Sthenorytis pernobilis (Fischer & Bernardi, 1857)<br /> EPITONIIDAE<br /> -265~275 m (-145~150 fms), Dredged, De Soto Canyon, Gulf of Mexico, Florida, U.S.A., Leg. J. Riley & Donna Black, 1970's, 27.8 mm <br /> <br /> With exquisitely raised blade-like axial ribs, the "Noble Wentletrap" is an incarnation of elegance and one of the most sought-after epitoniids of all by collectors. Widely distributed from southeastern U.S.A. around Florida to throughout Gulf of Mexico and Caribbean Sea to Brazil; it is a deep-water species with most specimens have been taken between -200~400 m deep and the deepest record going down to around 1400 m. Majority of specimens circulating today have surfaced from dredgings by the renowned J. Riley and Donna Black, who dredged deep habitats off western Florida during 1960's-1970's and sold the specimens yielded by the bucket -- it was luck of the draw whether one got something rare like Sthenorytis pernobilis. Other specimens have been collected here and there throughout its range, but these were extremely rare. Since the Blacks Dredgings stopped it has become a very scarce species, until today. <br /> <br /> Though a little-varied species, individuals do vary somewhat in shell characters such as the density of varices and the extent of blade-like extension. Most specimens have damaged varices, specimens displaying the full glory of the species are truly difficult to come by. Like other epitoniids it is a suctorial feeder on cnidarian animals, and it is considered to be a specialist on sea anemones and is likely semi-parasitic on them. Typical shell length around 30 mm, extremely large specimens can exceed even 50 mm. <br /> <br /> It is the only Atlantic species of the genus and can only be confused with its Pacific sister-species S. turbina (Dall, 1908) which occurs in similar depths and latitudinal ranges but in a different ocean, where it is best known from the Galápagos Islands. In intact specimens the two species are easily distinguished as the varices of S. pernobilis lacks the strong angulation typical of S. turbina. Another Pacific species of the genus is S. dianae (Hinds, 1844) ranging between Costa Rica and Galápagos Islands, but S. dianae exhibits much fewer varices per whorl and cannot be confused with S. pernobilis.
Colubrellina condita (Gmelin, 1791) <br /> BURSIDAE<br /> -20 m, Dived, Bungin Island, Sumbawa, West Nusa Tenggara, Indonesia, 2022/vii, 105.2 mm <br /> <br /> Characterised by a high spire and very finely granulose sculpture, the "Tall Frog Shell" is perhaps the rarest of all living bursid species. Despite being quite widely distributed in the Indo-West Pacific, ranging from Amami Islands, Japan to Vietnam to eastern Australia and New Caledonia, it appears to be extremely rare across the entire range. A carnivorous and predatory gastropod, it inhabits coral rubble bottoms in moderate depths around -10~100m and is most likely a vermivorous species feeding on polychaete worms like other bursids. The reasons behind its apparent rarity is unclear, and searches for the 'jackpot' locality continues. The fact that it can be found in shallow water well into the diving depths only adds to its mythical image. More specimens are known from the Philippines than other localities, almost certainly due to the great magnitude of shelling activity there. Typical shell length around 85mm, extremely large specimens may exceed even 115mm. <br /> <br /> Large, tall spired form of the very common Dulcerana granularis (Röding, 1798) is often (inadvertently or intentionally) mis-identified as C. condita, but the granulate sculpture of D. granularis is so much coarser that there is really no room for confusion. The spiral cords in B. granularis are also less numerous and wider (generally), plus the varices occur regularly every 180 degrees (in B. condita the varices are slightly offset every whorl). Part of the confusion is probably due to the great variability in form and size displayed by B. granularis, which is usually only around 40mm in shell length but occasionally exceed 80mm. In contrast, B. condita is actually a very little-varied species both in form and sculpture, although the colouration is somewhat variable from almost completely white to carrying extensive flame-like streaks of brown. <br /> <br /> In many adult specimens the early whorls are eroded or broken off, producing a 'truncated' appearance. The specific epithet is sometimes mis-spelt as 'conditina', probably due to Dr. Tadashige Habe using this spelling in his "Shells of the Western Pacific in Color Vol. 2" (1964). Two well-known synonyms are Ranella candisata Lamarck, 1822 (has been mis-spelt as 'candista' and 'caudisata') and Tritonium candisatum Röding, 1798. When species traditionally placed in genus Bursa was revised using molecular data and split into a few genera, this species was not available for study and its generic assignment remains uncertain; it is thus for the time being placed in the genus Colubrellina, for which it is the type species.
Raybaudia joycae (Clover, 1970)<br /> CYPRAEIDAE<br /> -150~200 m, Trawled, East China Sea, 49.7 mm <br /> <br /> Only found in a small part of the western Pacific ranging between Japan and Taiwan, the "Joyce's Cowrie" is a deep water cypraeid living in depths between about -100~300 m. The first specimen was collected in 1968 from 280 m deep in Taiwan Strait by a Taiwanese fishing vessel; it was recognised as a new species by the American conchologist and dealer Phillip W. Clover who soon described it in 1970 based on this single specimen. Since then it has become widely recognised as a classic rarity, being one of the rarest cowries of the region. Majority of specimens in the early years surfaced from Taiwan, supplemented by a few from southern Japan. Around 2010s, Chinese trawlers operating in the East China Sea yielded the first reliable source of this species, though they remained rare. Recently, reduction in the activity of the Chinese trawlers has led this species to become elusive as before once again. For some reason the shell in this species is very prone to growth lines and damage and the pattern development is extremely variable, with many specimens nearly patternless. As such, fine specimen shells with no major growth scar and decent colouration plus pattern remains very scarce. Though its diet is not known specifically, it is probably an omnivorous grazer feeding on sponges and other overgrowth. Typical shell length around 50 mm, very large specimens can exceed 65 mm. <br /> <br /> It is very similar in appearance to its sister species R. porteri (Cate, 1966), and for some years since its description many authors treated it as a subspecies of R. porteri. Today, the two are generally accepted to be distinct at the species level. The most obvious difference between the two is the teeth -- R. joycae exhibits much coarser teeth which extends significantly to either side of the aperture, while R. porteri has fine teeth that do not extend. Furthermore, the shell height of R. joycae is much greater than R. porteri of the same size; the dorsal spotting is also typically much more sparse in R. joycae than R. porteri. Though the distribution of the two species overlap in Taiwan, the distribution of R. porteri extends greatly to the south, ranging to the Philippines and even Queensland, Australia and Fiji. For many years these two species were placed in the genus Lyncina, until 2017 when they were separated out in their own genus Raybaudia, a name honouring the Italian conchologist Luigi Raybaudi Massilia (1913-2003). The specific epithet of R. joycae was dedicated to Joyce Clover, wife of the author Phillip W. Clover at the time of its description.
Bayerius knudseni (Bouchet & Warén, 1986)<br /> BUCCINIDAE<br /> -6465 m, Aleutian Trench (51°55.94'N, 166°51.84'W), By Agassiz Trawl, R/V SONNE Expedition SO293, 2022/viii/18, 22.0 mm (Senckenberg Natural History Museum Frankfurt Collection)<br /> <br /> Widely distributed in abyssal plains and trench habitats throughout Pacific Ocean, Bayerius knudseni is a small buccinid specialising in very deep waters between about 4700-6500 m deep. First described from the Kermadec Trench off New Zealand in the southern Pacific, morphologically indistinguishable individuals were later also found in and around Kuril-Kamchatka Trench in the northwestern Pacific. The specimen shown was captured by an Agassiz Trawl on-board our recent R/V SONNE SO293 "AleutBio" expedition from 6465 m deep in the Aleutian Trench, extending its distribution further north. An inhabitant of muddy bottoms, it is a carnivorous, predatory, and often scavenging gastropod. Though it is common where it occurs, the great depth of its habitat means it is rarely brought to the surface. Typical shell length around 15 mm, the largest known specimens approach 25 mm. Originally described in the genus Calliloncha, which is now considered to be a junior synonym of Bayerius. It is named in honour of Jørgen Knudsen (1918-2009), a Danish malacologist who was the curator of Mollusca at the Natural History Museum of Denmark between 1957-1986.
A super exciting find from our RV SONNE AleutBio expedition — a mythical “living fossil” monoplacophoran!<br /> <br /> Veleropilina oligotropha (Rokop, 1972)<br /> NEOPILINIDAE<br /> -6465 m, Aleutian Trench (51°55.94'N, 166°51.84'W), By Agassiz Trawl, R/V SONNE Expedition SO293, 2022/viii/18, 5.4 mm (Senckenberg Natural History Museum Frankfurt Collection)<br /> <br /> Long thought to be extinct since nearly 400 million years ago, the discovery of the first living monoplacophoran mollusc in May 1952 -- Neopilina galatheae Lemche, 1957 from 3750 m deep off Costa Rica -- was a truly sensational moment in zoology. Though superficially similar to limpets, monoplacophorans have a completely different anatomy such as lacking a true head and possessing multiple pairs of ventral, external gills, making them a distinct class of molluscs. Today, more than 35 living species have been described in seven genera, all contained in the family Neopilinidae; though many argue that the smaller genera united by a series of shell and anatomical features should be placed in a separate family, Micropilinidae. They are the rarest class of living molluscs, with each species known from only one or few collecting events.<br /> <br /> Veleropilina oligotropha is among the deepest living monoplacophorans and was first described from a single specimen collected 6065-6079 m deep in the Central Pacific, north of Hawaiian Islands. The specific epithet 'oligotropha' is a reference to its nutrient-poor, near-hadal habitat. In the last decade, it was rediscovered from about 4000 m depth in a section of the Pacific abyssal plain rich in manganese nodules known as the Clarion-Clipperton Zone, located roughly between Hawaii and Mexico. There it apparently lives on the manganese nodules, suggesting that it prefers hard substratum. It probably feeds on the surface biofilm covering the substrate, as has been observed for other monoplacophorans.<br /> <br /> The specimen shown was captured by an Agassiz Trawl on-board our recent R/V SONNE SO293 "AleutBio" expedition from 6465 m deep in the Aleutian Trench. Though it matches V. oligotropha in key characteristics of both shell morphology and external anatomy, this is far north of its known distribution and would be a significant range extension. Furthermore, its shell length of 5.4 mm is much larger than the few other known specimens that are typically around 2-3 mm. The apex of our specimen projects more anteriorly than the smaller specimens, but this likely reflects an ontogenetic change due to its larger size. This identification is therefore tentative, and further anatomical and genetic work in the laboratory is required for confirmation. Either way, this is a super exciting find!<br /> <br /> Original photographs by Julia D. Sigwart, Post-processing, composition, and text by Chong Chen.
Bayerius arnoldi (Lus, 1981)<br /> BUCCINIDAE<br /> -6465 m, Aleutian Trench (51°55.94'N, 166°51.84'W), By Agassiz Trawl, R/V SONNE Expedition SO293, 2022/viii/18, 42.8 mm (Senckenberg Natural History Museum Frankfurt Collection)<br /> <br /> A large buccinid inhabiting very deep abyssal waters between approximately 4500 m to 6500 m depth, Bayerius arnoldi is among the deepest members of the family. Originally described from specimens collected by the Soviet research vessel RV Vityaz in Japan Trench, it was subsequently also found from the Kuril-Kamchatka Trench and the Aleutian Trench as well as the surrounding abyssal plains, making it a very widely distributed species in the northern Pacific. A carnivorous, predatory, and often scavenging gastropod, it typically inhabits normal muddy bottoms but in Japan and Aleutian trenches it has also been reported from hydrocarbon seeps where they likely feed on large, symbiotic, vesicomyid clams. Though this species is not uncommon in its natural habitat, due to the abyssal depth it is a very difficult species to collect. The specimen shown was captured by an Agassiz Trawl on-board our recent R/V SONNE SO293 "AleutBio" expedition from 6465 m deep in the Aleutian Trench, within its known distribution range. Typical shell length around 40 mm, very large specimens can reach 55 mm. It is most similar to the congener Bayerius holoserica (Lus, 1971) known only from Kuril-Kamchatka Trench and its surrounding abyssal plain, but the two can be distinguished by B. arnoldi having twice as many spiral cords. The spiral cords of B. arnoldi vary in strength, with some becoming strongly raised primary cords which are lacking in B. holoserica.
An amazing find from our ongoing “AleutBio” expedition on-board R/V SONNE!<br /> <br /> Grimpoteuthis imperator Ziegler & Sagorny, 2021<br /> OPISTHOTEUTHIDAE<br /> -6279 m, Aleutian Trench (53°33.42'N, 161°14.99'W), By Agassiz Trawl, R/V SONNE Expedition SO293, 2022/viii/30, c. 290 mm (Senckenberg Museum Frankfurt Collection)<br /> <br /> The majestic "Emperor Dumbo" is a cirrate 'dumbo' octopus native to abyssal depths of northern Pacific Ocean. Described from a single male adult serendipitously dredged between 3913-4417 m deep in the Bering Sea portion of the Emperor Seamount Chain on-board the R/V SONNE cruise SO247, its discovery made the headlines worldwide and it was selected as one of the "Ten remarkable new marine species from 2021" in the World Register of Marine Species (WoRMS). A carnivorous and preadatory cephalopod, it is thought to capture small invertebrate animals (mainly annelid worms, bivalves, and small crustaceans) in its webbed arms and then use cirri on the arms to transfer the prey into the mouth. Known specimens have mantle length around 100 mm and body length around 300 mm.<br /> <br /> The specimen shown was captured by an Agassiz Trawl on-board our recent R/V SONNE SO293 "AleutBio" expedition from 6279 m deep in the Aleutian Trench, not far from the type locality of G. imperator. Though gross morphological features appear to match the holotype, further confirmation of its identification will be carried out in a laboratory post-cruise using finer anatomical features and molecular data. Our record is much deeper than the type locality, but perhaps not unexpected as dumbo octopuses in the genus Grimpoteuthis are known to be the deepest-living octopuses, with the deepest confirmed record being a sighting at 6957 m depth in the Java Trench. Earlier on our expedition, we also spotted a living individual of presumably the same species in about 5300 m depth on the southern wall of Aleutian Trench. Intact Grimpoteuthis specimens are very scarce due to the great depths they inhabit and also that majority of the specimens collected are heavily damaged, since dredges and trawl gears typically obliterate gelatinous animals. It is truly surprising that both the holotype and this specimen were recovered intact – an amazing feat for which we are grateful!
Cardiomya filatovae Scarlato, 1972<br /> CUSPIDARIIDAE<br /> -3463 m, Bering Sea (54.55°N, 172.58°W), By Agassiz Trawl, R/V SONNE Expedition SO293 "AleutBio", 2022/vii/27, 35.2 mm (Senckenberg Museum Frankfurt Collection)<br /> <br /> The "Filatov's Cuspidaria" is a large cuspidariid characterised by numerous radial ribs on the shell extending into the rostrum, with the interspaces being much wider than the ribs themselves. First described from a single empty shell found by the Gagara expedition in 3350 m deep in the Kuril Basin, it has since been recorded from Sea of Okhotsk and Bering Sea to the Aleutian Islands between the bathyal depths of 3260-3900 m. Despite numerous research expeditions to this wide range of northern Pacific over the years, only about 20 specimens have been collected, making it a very rarely seen species. The specimen illustrated here was collected by Agassiz Trawl from our recent 2022 "AleutBio" expedition on-board R/V SONNE in the Bering Sea, within the known range of the species. Like other cuspidariid bivalves, it is presumably a carnivorous and predatory bivalve feeding mainly on small crustaceans, capturing them by a sudden dramatic extenion of the siphon aided by a muscular septum that characterise the group. Typical shell length around 30 mm, very large specimens may reach 40 mm. Though it is similar in shell characters to closely-related congeners such as C. behringensis (Leche, 1883) and C. nipponica (Okutani, 1962), the radial sculpture with wider interspaces makes it clearly separable. It was named in honour of the Russian malacologist Zinaida Alexeyevna Filatova (1905-1984), Head of the Benthic Laboratory at the Shirshov Institute of Oceanology, who worked extensively on deep-sea molluscs.
Another deep-water species from our ongoing R/V SONNE “AleutBio” cruise!<br /> <br /> Aforia abyssalis Sysoev & Kantor, 1987<br /> COCHLESPIRIDAE<br /> -5280 m, Aleutian Trench (50°37.70'N, 169°46.72'W), By Agassiz Trawl, R/V SONNE Expedition SO293. 2022/viii/08, 57.5 mm (Senckenberg Museum Frankfurt Collection)<br /> <br /> Widely distributed in the lower abyssal depths of northern Pacific (3800-5500 m deep) approximately between Hokkaido, Japan and Alaska, U.S.A., the "Abyssal Aforia" is a cochlespirid "turrid" snail characterised by a shell sculpture consisting of high density of narrow spiral ribbing. In adult specimens the earlier whorls are almost always corroded away, due to its habitat being typically below the carbonate compensation depth. Generally a little-varied species, though individuals do vary slightly in their shell height to width ratio and the strength of the shoulder keel. In most specimens the keel is weak and hardly noticeable, but a few known specimens appear to carry considerably stronger carination.<br /> <br /> Although it is not uncommon in its natural habitat, the bathyal depth makes it a very challenging species to collect. The specimen shown here was obtained by the means of an Agassiz Trawl on the German R/V SONNE. A carnivorous and predatory gastropod inhabiting muddy bottoms, it most likely feeds on other invertebrate animals. Typical shell length around 50 mm, very large specimens may exceed 65 mm.<br /> <br /> Follow us here:<br /> https://aleutbio.sgn.one/en/
Something special from our current expedition: <br /> <br /> Tropidofusus aequilonius (Sysoev, 2000)<br /> COLUMBARIIDAE<br /> -3463 m, Bering Sea, By Agassiz Trawl, R/V SONNE Expedition SO293 "AleutBio", 2022/vii, 50.0 mm (Senckenberg Museum Frankfurt Collection)<br /> <br /> Only known from abyssal depths between around 3500-3900 m deep in the Bering Sea, the "Northern Pagoda" is not only the deepest-dwelling member of the family but also the single species inhabiting waters north of central Japan. In the literature it is only known from two specimens, collected on two occasions in the Bering Sea, comprising the type series -- making it an extremely rare species, attributable to its remote range and the very deep habitat. The specimen illustrated here was collected by Agassiz Trawl from our expedition on-board R/V SONNE. Living on muddy bottoms, though its exact diet is not known it is almost certainly a carnivorous and predatory gastropod feeding on polychaete worms like other columbariids. Typical shell length around 50 mm, the largest known specimen is 61.8 mm in length (the holotype).<br /> <br /> Originally described in the genus Fulgurofusus, it was later included in Tropidofusus when that genus was proposed based on low spire with a strong peripheral keel combined with very thin shell that lacked any axial sculpture. Currenly only three species are included in Tripidofusus, the other two being T. ypotethys Harasewych, 2019 from New Zealand and T. benthocallis (Melvill & Standen, 1907) from Scotia Sea. This makes Tropidofusus a genus with a disjunct distribution in high latitudes of the two hemispheres, and T. aequilonius is more closely related to two far-south species than numerous other columariid species in habiting subtropical to tropical waters. From the two southern species, T. aequilonius differs by having a weaker anterior carina and the presence of numerous weaker spiral striae anterior of the anterior carina.<br /> <br /> Though apparently a little-varied species judging from the known specimens, specimens do differ in the number of weaker spiral striae, and sometime an additional striae is present between the anterior carina and the peripheral keel. The specific epithet 'aequilonius' means northern in Latin, referring to its far-north distribution compared to all other columbariids.
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