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.

Ericusa naniforma Bail & Limpus, 2013 <br />
VOLUTIDAE<br />
-140 m, Taken by remotely operated vehicle (ROV), Off Rottnest Island, Western Australia, Australia, 58.9 mm <br />
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At an average shell length of just 60 mm and the largest specimens reaching 75 mm, Ericusa naniforma is the smallest known species of the Australian volutid genus Ericusa. Inhabiting moderately deep waters between 200~400 m deep, it has a rather narrow distribution between the Abrolhos Islands and Cape Leeuwin in Western Australia. Though its specific feeding ecology is not known, it is probably a predatory and carnivorous gastropod feeding on invertebrate animals like other volutids. The shell form differs very little among individuals and always carries a bulbous protoconch and strong, raised axial ridges, but the light beige shell pattern consisting mostly of blotches and spiral lines varies greatly. Most specimens are stained by a layer of rusty mud obscuring the shell patterns, hinting at a muddy substrate. A rarely seen species, vast majority of specimens have been crabbed; recently remotely operated vehicles have returned some excellent specimens. The species name 'naniforma' refers to its very small size among congeners. <br />
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The first specimens were trawled by the Western Australian Fisheries Department off Rottnest Island in the 1980’s, but it took about three decades for it to be named as a new species. Initially, it was thought to be a dwarf form of the very variable Ericusa papillosa (Swainson, 1822). Indeed, there is a dwarf population of E. papillosa extending from south of Cape Leeuwin into the Great Australian Bight; just south of the range for E. naniforma. Superficially this dwarf E. papillosa appears similar to E. naniforma but they can be reliably differentiated by the bulbous, protruding protoconch, the tapered spire, and the less well-defined patterning in E. naniforma. Though the dwarf E. papillosa also exhibit axial ribbing, these are much more irregular and stronger compared to those of E. naniforma. The two are not known to occur sympatrically.

Chaetoderma shenloong Chen, Liu, Gu, Qiu & Sun, 2024<br />
CHAETODERMATIDAE<br />
-1385 m, Inside dark-coloured mud around a vesicomyid clam colony, Haima methane seep (16°43.937'N, 110°27.681'E), Taken with a push-corer by ROV Pioneer, R/V Xiangyanghong 01 cruise XYH01-2022-06, 2022/ix/20, 150.2 mm <br />
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The first aplacophoran mollusc known to specifically inhabit deep-sea cold seep ecosystems driven by microbial chemosynthesis, Chaetoderma shenloong is so far known from two methane seeps in the South China Sea between 1100~1400 m deep. It lives buried deep in black, anoxic mud among chemosymbiotic vesicomyid clams, making it invisible from the surface and rather difficult to sample. Only a few specimens have been collected so far using long push cores mounted on remotely operated vehicles (ROVs), and it remains a very rare species. Though its feeding ecology remains unclear it may feed on bacteria in the sediment given the unusual habitat, and a potential symbiotic bacteria has been located in its intestine. <br />
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A gigantic chaetodermatid caudofoveate with an average body length around 120 mm and very large specimens exceeding 150 mm, it is the second largest caudofoveate known globally behind Chaetoderma felderi Ivanov & Scheltema, 2007 from Gulf of Mexico, which reaches 365 mm. These two species both possess isosceles-triangular sclerites that clearly distinguish them from other congeners, while the much narrower body form of C. felderi makes it easily separable from C. shenloong. <br />
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The species name 'shenloong' means 'divine dragon' in Mandarin Chinese, alluding the body form and sclerites of caudofoveates to Chinese dragons ('loongs'). This is also a reference to the Chinese saying 'You shall never see the head and tail of Shén Loong at the same time' used to refer to something highly elusive, like C. shenloong hidden deep inside black mud. Furthermore, this name takes inspiration from the dragon character Shenron ( = also Shenlong or Shenloong) in the Japanese manga series Dragon Ball by the artist Akira Toriyama (1955-2024).

Symmetriapelta radiata Chen, Poitrimol & Matabos, 2024 <br />
PELTOSPIRIDAE<br />
Holotype (MNHN-IM-2019-30341), 6.2 mm <br />
-3388 m, La Scala hydrothermal vent field, Woodlark Basin (9°47.944'S, 155°03.161'E), R/V L'Atalante CHUBACARC cruise, ROV Victor 6000 dive #738, 2019/v/28 <br />
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A limpet-formed peltospirid, Symmetriapelta radiata is only known from the La Scala hydrothermal vent field in the Woodlark Basin, southwestern Pacific. All known specimens have been collected during a single research cruise to that vent field in 2019, at 3388 m deep where individuals were found on surfaces of sulfide chimney structures or shells of the large abyssochrysoidean snail Ifremeria nautilei Bouchet & Warén, 1991. It is thought to be a grazing gastropod feeding on bacterial films growing on these substrates. Typical shell length around 5 mm, the largest specimen recorded so far is 6.2 mm. <br />
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The specific epithet 'radiata' refers to the numerous radial ribs forming the shell sculpture. The strength of this sculpture is very variable among individuals, ranging from very weak striations of equal strength to alternating between weak and strong, scaly ribs. This means it is difficult to separate this species from its two congeners, S. wareni Beck in Chen & Sigwart, 2023 and S. becki Chen, Poitrimol & Matabos, 2024, based on shell sculpture as its variation encompasses that of both congeners. Instead, the key character distinguishing S. radiata is in the radula, where the three innermost lateral teeth carry strong serrations lacking in the other two described Symmetriapelta species. The other two species are also not distributed in the Woodlark Basin.

Symmetromphalus mithril Chen, Poitrimol & Matabos, 2024<br />
NEOMPHALIDAE<br />
Holotype (MNHN-IM-2019-30328), female, 11.2 mm<br />
-3388 m, La Scala hydrothermal vent field, Woodlark Basin (9°47.944'S, 155°03.161'E), R/V L'Atalante CHUBACARC cruise, ROV Victor 6000 dive #738, 2019/v/28 <br />
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A limpet-formed neomphalid, Symmetromphalus mithril was recently discovered from a deep-sea hot vent field ('La Scala') in the Woodlark Basin, southwestern Pacific. It is so far only known from specimens collected during a single research cruise to the La Scala vent field at 3388 m depth, and has been shown to be genetically distinct from other congeners inhabiting other vents in the western Pacific. A filter-feeding gastropod, it lives attached to the surface of sulfide chimneys and has evolved a greatly enlarged gill to filter bacteria and other organic matter from the surrounding seawater. The shell morphology is rather variable as the edge is formed to fit the chimney surface, and is thus typically irregular. Like other neomphalids, the left cephalic tentacle develops into a large penis in males only. Typical shell length around 10 mm, the largest specimen recorded so far is 12.7 mm. <br />
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It stands out among its congeners by the silvery white periostracum in adults, as opposed to yellowish brown or tan in other species. The specific epithet 'mithril' alludes this periostracum to the fictional silvery metal of the same name in J.R.R. Tolkien's "The Lord of the Rings"; it means 'grey glitter' in Sildarin, one of the elvish languages constructed by Tolkien. The following characters also help distinguish it from other Symmetromphalus species: 1) a protoconch about 220–230 μm in size, 2) shell lacking broad and raised radial ribs, and 3) radula with 10–12 pairs of marginal teeth.

Fusivoluta wesselsi Kilburn, 1980<br />
VOLUTIDAE<br />
-150~200 m, Trawled, Southern Mozambique, 2003/v, 21.7 mm <br />
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Characterised by numerous sinuous axial ribs on a narrow, fusiform, and shouldered shell, the "Wessels' Volute" is a small volutid with a narrow range between Tugela Bank just north of Durban in South Africa and southern Mozambique. A rarely seen species, it inhabits mud to rubble bottoms in moderate depths between 50~200 m. Though its feeding ecology is not known specifically, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals like other Fusivoluta species. The shell surface is pale white, but may appear brownish when stained with mud. Typical shell length around 20 mm, very large specimens can exceed 25 mm. <br />
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It is perhaps most similar to Fusivoluta pyrrhostoma (R. B. Watson, 1882), another South African species, in overall appearance; but F. pyrrhostoma is a much larger species reaching about 90 mm in shell length and thus adult specimens have a much smaller protoconch relative to the teleoconch. The first few whorls of F. wesselsi are much more shouldered than that of F. pyrrhostoma, easily separating the two species even when comparing similar-sized specimens. It was named in honour of Hugo Jurie Wessels (1926-1992), a South African doctor and farmer who collected many things such as coins, stamps, eggs, as well as seashells with a focus on cowries.

Distorsio burgessi Lewis, 1972<br />
PERSONIDAE<br />
-20 m, Dived in on coral reef, Oahu, Hawaii, U.S.A., 47.9 mm <br />
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The "Checkerboard Distorsio", aptly named for its unmistakeable latticed parietal shield that makes it stand out among all known Distorsio species. Criss-crossed with spiral and axial ribs at similar strengths and spacings, the shield is ornamented by a series of squares, the borders of which are strikingly highlighted by a dark, reddish brown colouration. A famed endemic species of the Hawaiian Islands, it was first illustrated by the hawaiian conchologist and physician Clarence M. Burgess (1908-1999) in August 1963 on the Hawaiian Shell News as an unidentified Distorsio species. Later in 1972, it was formally described by the malacologist Harold Lewis (1927-1998) of Philadelphia as more material (a grand total of five specimens) became available. To this day it remains a very rare species with the majority of specimens collected being long-dead empty shells that have lost most of the colouration; very few live specimens have been taken since its discovery. A carnivorous and predatory gastropod, it is found in shallow subtidal waters down to about 40 m in depth and probably feeds on polychaete worms like other personids. Typical shell length around 50 mm, very large specimens are known to attain 70 mm. <br />
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Lewis named this species in honour of Burgess who first illustrated it in the literature. Since its discovery, the remarkable morphological similarity and completely opposite distribution patterns with its sister species Distorsio anus (Linnaeus, 1758) has been extensively discussed. In stark contrast to D. anus which is common across its extremely wide distribution range across the Indian and Pacific oceans from Hawaii to South Africa, D. burgessi is restricted to Hawaii where the two species co-occur in similar depths, though D. anus is by far more common. Lewis initially thought D. burgessi was a local variant of D. anus, until he had seen multiple specimens of D. burgessi which displayed consistent differences from a large series of Hawaiian D. anus. The two species have quite similar shell shapes, although D. burgessi lacks a strong secondary groove on the left side of the parietal shield that is characteristic of D. anus. The two differ significantly in shell colouration, however, where D. anus lacks the checkerboard pattern on the parietal shield and instead typically has dark patterns on the dorsum, across the body whorl. In D. burgessi, the body whorls only carry pale orange stains and in larger specimens even these orange stains are often absent, rendering the dorsum white. Furthermore, the siphonal canal of D. anus is also longer than that of D. burgessi. When live both species possesses an operculum and a hairy periostracum; the periostracum of D. burgessi is different from that of D. anus in being lighter in colouration and also in carrying shorter hairs.

Turrisipho lachesis (Mörch, 1869)<br />
COLIDAE<br />
-300~315 m, Trawled on muddy sand, 76°20'N 31°00'E, Barents Sea, Russia, 2000/ii/01, 42.3 mm <br />
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The "Destiny Colus" is a cold-water colid characterised by a very tall spire with about 10 slowly-expanding whorls in adults. A wide-ranging species in the northern Atlantic, it was originally described from western Greenland but has also been found off Nunavut in Canada, Faroe Islands, Norway, and the Barents Sea, among other localities in-between (74°N to 46°N and 78°W to 0°W). Despite its wide distribution it is a very rare species across its range. A carnivorous and predatory gastropod, it inhabits soft bottoms and has a wide bathymetric range like many buccinoidean species; depending on the local environment it can be found as shallow as -20 m and as deep as -1200 m, most specimens have been trawled between 200~500 m deep. The shell is covered in a layer of thin, hirsute periostracum but it peels easily and is lost in most specimens. Typical shell length around 35 mm, very large specimens can approach 50 mm. <br />
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The specific epithet 'lachesis' refers to the Greek goddess Lachesis, the middle-sister of the Three Fates (Moirai) -- Atropos, Lachesis, and Clotho. The Fates determine humans' destiny through manipulating the threads of life, which is spun by Clotho, drawn out by Lachesis, and cut by Atropos; hence the common name "Destiny Colus". Turrisipho undulatus (Friele, 1881) is a junior synonym.

Phalium exaratum (Reeve, 1848)<br />
CASSIDAE<br />
-50~60 m, Dredged, Taken from holothurian, Mahé, Seychelles, 69.1 mm <br />
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The "Furrowed Bonnet" is a rare cassid with a confined distribution range around the Mascarene Plateau between Seychelles and off Madagascar. A member of the Phalium bandatum (Perry, 1811) group, it is characterised by a shell with numerous spiral grooves covering the body whorl and the posterior part developing into three or four coarsely granulated ridges. The parietal callus is thick and well-developed in adults, where the parietal shield is developed into a complete oval. Development of the reddish brown rectangle-like patterns on the shell varies greatly among individuals, and the amount of granulation on the spire is also somewhat variable. A carnivorous and predatory gastropod feeding primarily on holothurians like other Phalium species, it is found on sandy and silty bottoms from shallow subtidal waters down to about 100 m deep. Typical shell length around 70 mm, very large specimens may reach 110 mm. Many authors have treated it as an Indian Ocean subspecies of P. bandatum in the past, but recently it has been considered as a separate species in its own right due to considerable differences from P. bandatum in both distribution and shell morphology.

Lyria kuniene Bouchet, 1979<br />
VOLUTIDAE<br />
-450 m, Dredged, Southwest off Isle of Pines, New Caledonia, 36.2 mm <br />
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Originally described from just a single specimen trawled off Isle of Pines, the "Kunié Volute" is a deep-water volutid endemic to New Caledonia. A very rare species characterised by sharp, clear-cut chestnut spiral lines visible only on the raised axial ribs, just a small number of specimens have been dredged live. Inhabiting waters around -200~500 m deep, it is a carnivorous and predatory gastropod feeding on other invertebrate animals. Larger shells tend to be much more shouldered than smaller ones, and the only other key variability is that the number of axial ribs can differ somewhat among individuals. The head-foot carries a striking pattern of numerous thick transverse reddish brown lines occasionally crossed by finer ones. Typical shell length around 50 mm, very large specimens may reach 80 mm. <br />
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Although some forms of L. boholensis Poppe, 1987 and L. planicostata (Sowerby III, 1903) can exhibit similar patterns of spiral lines only on the axial ribs, L. kuniene clearly differ in having a larger protoconch, a brighter background colouration, and a complete lack of 'zigzagged' lines. The specific epithet 'kuniene' is derived from "Kunié", the Kanak (language of the indigenous Melanesian inhabitants of New Caledonia) name for Isle of Pines.

Coralliophila ceciliae Araya, Garrido, Bonard & Aliaga, 2023 <br />
MURICIDAE<br />
-1 m, Under rocks living among sea anemones. south of Playa Rocas Negras (27°08'33"S, 70°53'51"W), Caldera, Region de Atacama, Chile, 14.0 mm (Holotype, MNHN 205454) <br />
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The first coralliophiline muricid recorded from continental Chile, the "Cecilia's Coral Snail" is a rare species known only from several specimens most of which are empty shells. These specimens were collected on or around large boulders in low intertidal waters down to shallow subtidal depths of about -2 m, between Caldera (27°S) and Chañaral de Aceituno (28°S) in Atacama, Chile. Live specimens were found among sea anemones, on which they presumably feed -- making it currently the only coralliophiline known to be associated with sea anemones in the entire eastern Pacific. Apart from slight differences in spire height it appears to be a rather little-varied species, judging from the few known specimens. Typical shell length around 15 mm, large specimens approach 20 mm. It was named after the Chilean malacologist Prof. Cecilia Osorio (University of Chile). The combination of the bright orange aperture, the lack of subsutural ramp, and a well-defined siphonal canal serves to distinguish this species from its known eastern Pacific congeners.

Rhinovasum triangulare (Smith, 1902)<br />
VASIDAE<br />
-40~50 m, Dived, Off south coast of Natal, KwaZulu-Natal, South Africa, 73.8 mm <br />
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The "Triangular Vase" is a vasid snail easily recognised by a shell with a strongly nodulose body whorl ending in a flaring, thinly glazed lip but lacking in ventral callus. A rare species only known from South Africa, vast majority of specimens have originated from off Natal. Inhabiting moderate depths between -20~100 m, it is a carnivorous and predatory gastropod feeding primarily on annelid worms. Though usually easily recognisable, the strength of nodules does vary among individuals. A thick, brown periostracum covers the shell when alive. Typical shell length around 70 mm, very large specimens may exceed 100 mm. <br />
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Since description its relationship with the "Truncate Vase" Rhinovasum truncatum (Sowerby III, 1892), another vasid endemic to South Africa, has been heavily debated. Most authors considered the two to belong to the same species, some treating them as forms and others as subspecies. The two differ morphologically in that the shell of R. truncatum lacks strong nodules and is generally of a paler colouration below the periostracum. The most recent treatise of the family Vasidae by the malacologist Geerat Vermeij in early 2024 (which also elevated Vasidae to family level again, instead of the previous subfamily rank under Turbinellidae) classified the two as separate and distinct species. At the same time, they were also moved from Vasum to a newly established genus Rhinovasum. Since apparent morphological intermediates between R. truncatum and R. triangulare are known, settling the true relationship between these two taxa definitively requires further study.

Variciscala raricostata (Sowerby II, 1844)<br />
EPITONIIDAE<br />
-5 m, Dived, Labuan Bajo, East Nusa Tenggara, Indonesia, 20.5 mm <br />
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Characterised by a random and irregular occurrence of thick varices over a background sculpture checkered by equal-strength axial and radial ribs plus very fine gemmules, the "Rare-ribbed Wentletrap" is an exquisite epitoniid with a very wide distribution across the entire Indo-West Pacific from Oman to Mauritius to Sri Lanka to Queensland, Australia. A very rare species known from scattered records in shallow subtidal waters between -1~25 m depth, it is presumably a predatory and perhaps parasitic gastropod feeding on cnidarians as is typical for epitoniids. An instantly recognisable species that cannot be confused with any other known epitoniids, the shell is little-varied with the exception of the varix placement. The head-foot has a whitish background overlaid by a fine net-like pattern of reddish brown, the cephalic tentacles are red. Typical shell length around 20 mm, very large specimens are known to exceed 25 mm. <br />
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Its scientific name has had a convoluted history, where in 1822 Lamarck first gave it the name Epitonium raricosta (Lamarck, 1822) despite already having used the same name for a different species in 1804, now Filiscala raricosta (Lamarck, 1804). This renders the 1822 name a junior homonym and thus unavailable for use in zoological nomenclature. Sowerby II recognised this problem, and in 1844 gave the replacement name Scalaria raricostata Sowerby II, 1844. Later, the genus Variciscala was established for its bizarre morphology with variable varices, and it is currently the only species in that genus. Variciscala kelea (Iredale, 1930) is a junior synonym.

Turbo debesi Kreipl & Alf, 2000<br />
TURBINIDAE<br />
-9 m, Dived, Albany, Western Australia, Australia, 16.4 mm <br />
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A very unusual member of genus Turbo, the "Debes' Turban" is characterised by a small shell with two spiral keels and a finely scaly sculpture. The strongest keel at the shoulder carries numerous triangular spines; the weaker basal keel often also carry spines but much smaller in comparison. The calcarous operculum has a central depression surrounded by two very deep ridges, and the operculum morphology became the basis for assigning it to Turbo rather than related genera such as Bolma or Astraea. It appears to be an extremely rare species, despite occurring at a shallow depth between 5~30 m deep where it lives on sand and coral debris. It is thought to be a herbivorous grazer feeding on algae like other turbinids, supported by some records collecting it on algae. Known specimens were all dived between Albany and north of Perth, and consequently it is considered to be an endemic of Western Australia. <br />
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Though it is somewhat variable in spine development and the development of reddish-brown colour patches on the shell, its strange morphology prevents it from being confused with any other known Turbo species, Typical shell length around 25 mm, very large specimens are known to approach 35 mm. This species was named in honour of Otto Debes of Heidelberg, Germany. The Australian conchologist and shell dealer Hugh Morrison was apparently the first to recognise this species as new to science, and he then passed it on to German conchologists Kurt Kriepl and Axel Alf for description.

Volutoconus mcmichaeli Habe & Kosuge, 1966<br />
VOLUTIDAE<br />
Trawled, Off Townsville, Queensland, Australia, 78.2 mm <br />
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The "McMichael's Volute" is a member of the eastern Australian "Volutoconus grossi (Iredale, 1927) complex", ranging between Cape Bowling Gree near Ayr to Great Palm Island in Queensland. A rather rare species inhabiting sandy bottoms of moderate depths around -30~100 m, it is a carnivorous and predatory gastropod feeding on other invertebrate animals. Typical shell length around 80 mm, very large specimens may reach 130 mm. It is one of three species in the "V. grossi complex" to exhibit a strongly ribbed protoconch, the other two being V. browni Bail & Limpus, 2013 and V. keppelensis Bail & Limpus, 2013. Usually V. mcmichaeli can be instantly differentiated by the much more well-defined spiral bands which are much darker than the tent-like patterns, ranging from very dark reddish brown to nearly black. However, rare specimens with light-coloured spiral bands have been found which are more easily confused with the other two species. Even then, the protoconch of V. keppelensis typically has more widely spaced ribs, and also the spire is shorter; while in V. browni the spire is taller and more tapered and the tent-like patterns are axially stretched. <br />
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This species was named in honour of Donald Fred McMichael (1932-2017), an Australian malacologist who published widely on both aquatic and terrestrial Australian molluscs. McMichael was a public servant of Australia who served in a wide range of posts during his life such as the Curator of Molluscs at the Australian Museum, Director of the National Museum of Australia, and Secretary of the Department of Home Affairs. Interestingly, after Habe & Kosuge published their name in 1966, McMichael published another description of the same animal as V. grossi helenae McMichael, 1966. Naturally, V. g. helenae is now treated as a junior synonym of V. mcmichaeli. For many years after its description, its taxonomic validity remained unclear with various authors treating it as a subspecies or form of V. grossi. Today it is considered a full species in its own right.

Volutoconus multiformis Bail & Limpus, 2013<br />
VOLUTIDAE<br />
-175~200 m, Trawled on sandy bottom, Off Swain Reefs, Queensland, Australia, 62.0 mm <br />
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Characterised by a domed protoconch densely ornamented with fine axial ribs, the "Multi-formed Volute" is a volutid in the eastern Australian "Volutoconus grossi (Iredale, 1927) complex". It is the only living eastern Australian Volutoconus with a finely ribbed protoconch which is more common in the western Australian species in the "Volutoconus hargreavesi (Angas, 1872) complex", but the shallow suture and a pastel reddish colouration sets it apart from those western species. Among the V. grossi complex it is also the smallest species with a typical shell length around just 65 mm, though very large specimens can occasionally exceed 90 mm. Indeed, prior to its formal description as a separate species it has been referred to as a 'dwarf form' of V. grossi for many years. <br />
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Ranging between Lady Musgrave Island to Swain Reefs and Elusive Reef in Queensland, it is a rather common species and by far the most available of all eastern Australia Volutoconus species. Living on sandy and muddy bottoms of moderate depths between about 150~250 m deep outside the Great Barrier Reef region, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals as is typical for the family. As its name suggests, it is quite polymorphic in terms of adult shell shape and sculpture, especially in that the spire height and strength of axial ribbing on the body whorl are very variable. The colouration also differs greatly among individuals, from saturation of the reddish background colour (even all-white specimens are known to occur) to distinctness of the darker spiral bands. Many specimens collected from muddy bottom have the body whorl covered by a thin layer of rusty stain.

Volutoconus browni Bail & Limpus, 2013<br />
VOLUTIDAE<br />
Trawled, Hydrographers Passage, Queensland, Australia, 89.5 mm <br />
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The "Brown's Volute" is a volutid in the eastern Australian "Volutoconus grossi (Iredale, 1927) complex", characterised by a strongly ribbed protoconch with a high, narrowly tapered spire. Ranging between Hydrographers Passage to Bait Reef of the Great Barrier Reef in Queensland, most specimens have been collected from Hydrographers Passage. Living on sand and coral rubble bottoms of moderate depths between about 80~100 m deep, it is presumably a carnivorous and predatory gastropod feeding on other invertebrate animals as is typical for the family. Its shell carries well-defined spiral bands of darker reddish brown and is covered by a pattern of axially stretched reddish brown tent-like marks. It is generally a very little-varied species, except minor variations in shell patterning. Typical shell length around 80 mm, very large specimens can exceed 110 mm. <br />
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Among the "V. grossi complex" it is most easily confused with V. keppelensis Bail & Limpus, 2013, which is quite similar but with a much shorter, more stout spire and the spiral bands are typically more diffuse plus the tent-like marks are less axially stretched. The recent finding of some possible intermediate forms between V. keppelensis and V. browni questions their separation at species level which requires further study. It has also been confused with V. mcmichaeli Habe & Kosuge, 1966, although they are actually easily told apart since V. browni lacks the very dark, blackish spiral bands that characterise V. mcmichaeli. It was named for Eddie Brown, a fisherman and shell collector who supplied numerous Australian specimens to the collecting community.

Volutoconus keppelensis Bail & Limpus, 2013<br />
VOLUTIDAE<br />
Trawled in prawn net at night, North Capricorn Channel, Queensland, Australia, 2021/iii, 76.8 mm　<br />
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A member of the eastern Australia "Volutoconus grossi (Iredale, 1927) complex", the "Keppel Bay Volute" is characterised by a very strongly ribbed protoconch with a broad and convex, relatively low spire. Ranging between northern Capricorn Channel to Mackay in Queensland, most specimens have been collected from Keppel Bay, hence the name. A rare species inhabiting sandy bottoms of moderate depths between about 50~100 m deep, it is a carnivorous and predatory gastropod feeding on other invertebrate animals. The shell carries slightly diffused reddish brown tent pattern, darker spiral bands may be either present or absent. The dorsal aspect of the foot is mottled with a similar but much more coarse tent-like, reddish brown pattern. Typical shell length around 80 mm, very large specimens can exceed 110 mm. <br />
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Among the "V. grossi complex" it is most easily confused with V. browni Bail & Limpus, 2013, which is differentiated by a much narrower, tapered spire and elongated body whorl marked with axially stretched tenting but is otherwise similar. The recent finding of some possible intermediate forms between V. keppelensis and V. browni questions their separation at species level which requires further study. It has also been confused with V. mcmichaeli Habe & Kosuge, 1966, although they are actually easily told apart since V. keppelensis lacks the very dark, blackish spiral bands that characterise V. mcmichaeli.

Verpa philippinensis (Chenu, 1843)<br />
PENICILLIDAE<br />
-10~20m, Dredged in sand, Nha Trang, Vietnam, 2013, 175.4mm <br />
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The "Philippines Watering Pot" is an unusual bivalve in the superfamily Clavagelloidea, known for the remarkable shift during development from growing a pair of true shells to building a calcareous tube, known as the adventitious tube. After settlement, it continues to grow its normal bivalved shell until about 2~3 mm in shell length, then aburuptly changes to making an adventitious tube. The tiny original vestigial valves remain on the outside of the tube, visible in an open state. A filter-feeding bivalve, it inhabits sandy bottoms from shallow subtidal depths down to about 100 m deep; though most specimens have been dived between 10~30 m depth. It is a widely distributed species in the western Pacific, where it ranges from southern Japan to northern Australia to the Philippines to Vietnam. <br />
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In life position, the 'watering-pot' end of the tube is buried in sand -- this end has a central slit surrounded by numerous small pores, which are in turn surrounded by a fringe of 'root-like' simple or bifurcating tubules. The number, size, and arrangement of these pores and tubules appear to vary greatly among individuals, likely reflecting morphological plasticity to suit different substrate types and conditions. The surface of the adventituous tube is ornamented by material from the animal's surrounding, mostly sand grains but occasionally also shells and stones. The other end is simple in construction, protruding above the sand to provide the siphons access to fresh seawater. <br />
<br />
Typical length of the adventituous tube around 130 mm, though extremely large specimens can grow to even 220 mm; those from Vietnam appear to be especially large. Although supposedly common in its suitable habitat, it is a rather uncommon species in collections as it is difficult to recognise and collect in the field. Due to its variable morphology, different forms have been given many names in the past, the most famous being Aspergillum strangulatum Chenu, 1843. This species has also been previously placed in genera Penicillus and Brechites.

Melanodrymia telperion Chen, Li, Sun, Beaulieu & Mullineaux, 2024<br />
MELANODRYMIIDAE<br />
-2513 m, From surface of inactive sulphide, Lucky's Mound site, East Pacific Rise (9°47.4031'N, 104°17.2122'W), R/V Atlantis cruise AT50-06, HOV Alvin dive 5134, 2022/xii/18, 1.2 mm (Holotype, SMF 374496) <br />
<br />
Only known from two inactive vent sites on the East Pacific Rise near the latitude of 9°50'N and between 2500-2550 m deep, Melanodrymia telperion is a melanodrymiid snail characterised by a lack of significant axial sculpture. Occurring on surfaces of inactive sulfide chimneys, M. telperion appears to feed on bacterial mats covering the chimeny surface. A rather scarce species even locally, its narrow and deep distribution makes it very challenging to collect. It is currently known from about a dozen specimens all collected by the manned submersible HOV Alvin during a single research expedition. Typical shell diameter around 1 mm, the largest known specimen is 1.2 mm. <br />
<br />
Melanodrymia species are characterised by a highly unusual 'discordant' surface sculpture which is neither axial nor radial -- raised elements appear at the suture and dissapear at the periphery. Together with the semi-transparent shell, this generates a texture like coarse frosted glass. No other known Melanodrymia species lack axial sculpture or have the base keel almost as strong as the peripheral keel, making M. telperion an easy species to identify. The apex is typically corroded in adult specimens. The specific epithet refers to Telperion (Quenya/Telerin, 'Silver + -rion'), the Silver Tree of Valinor in J.R.R. Tolkien's legendarium. The apical view of M. telperion resembles a full moon, resonating with Telperion as his last flower would eventually become the Moon of Middle-earth. <br />
<br />
Deep-sea hydrothermal vents have been eyed for deep-sea mining due to their 'chimney' sulfide structures being high-grade mineral ores, but this threatens hundreds of vent-endemic animal species. Recently, focus has been shifting to inactive sites where venting activity has ceased, as these sites lack high-density faunal communities typical of active sites. Nevertheless, we know little about the animals that occur on inactive sulfides, and recent findings of novel species like M. telperion suggest these inactive sites are also likely home to many endemic species that do not live anywhere else -- including active vent sites. <br />
<br />
(2024/ii/01)

Melanodrymia laurelin Chen, Li, Sun, Beaulieu & Mullineaux, 2024<br />
MELANODRYMIIDAE<br />
-2511 m, From surface of inactive sulphide, Lucky's Mound site, East Pacific Rise (9°47.4132'N, 104°17.2325'W), R/V Atlantis cruise AT50-06, HOV Alvin dive 5135, 2022/xii/19, 1.6 mm (Holotype, SMF 374491) <br />
<br />
A melanodrymiid snail characterised by numerous short spines on the spiral keel, Melanodrymia laurelin is only known from two inactive vent sites on the East Pacific Rise near the latitude of 9°50'N and between 2500-2550 m deep. Occurring on surfaces of inactive sulfide chimneys, M. laurelin appears to feed on bacterial mats covering the chimeny surface. Although locally quite common, its specialised and very narrow habitat means it is very difficult to collect. It is currently known from a few dozens of specimens all collected by the manned submersible HOV Alvin during a single research expedition. Typical shell diameter around 1.5 mm, the largest known specimen is 1.8 mm. <br />
<br />
Melanodrymia species are characterised by a highly unusual 'discordant' surface sculpture which is neither axial nor radial -- raised elements appear at the suture and dissapear at the periphery. Together with the semi-transparent shell, this generates a texture like coarse frosted glass. No other known Melanodrymia species carry similar spines on the shoulder periphery, making M. laurelin instantly recognisable. The apex is typically corroded in adult specimens. The specific epithet refers to Laurelin (Quenya, 'Song of Gold'), the Golden Tree of Valinor in J.R.R. Tolkien's legendarium. The apical view of M. laurelin resembles a sunburst shape, resonating with Laurelin as her last fruit would eventually become the Sun of Middle-earth. <br />
<br />
Deep-sea hydrothermal vents have been eyed for deep-sea mining due to their 'chimney' sulfide structures being high-grade mineral ores, but this threatens hundreds of vent-endemic animal species. Recently, focus has been shifting to inactive sites where venting activity has ceased, as these sites lack high-density faunal communities typical of active sites. Nevertheless, we know little about the animals that occur on inactive sulfides, and recent findings of novel species like M. laurelin suggest these inactive sites are also likely home to many endemic species that do not live anywhere else -- including active vent sites. <br />
<br />
(2024/i/25)

Manaria chinoi Fraussen, 2005<br />
EOSIPHONIDAE<br />
-100~200 m, Trawled, Off Balut Island, Davao Occidental, Philippines, 2000's, 92.6 mm <br />
<br />
The "Chino's Whelk" is a large eosiphonid whelk only known from the southern Philippines, where it is has been collected from rather deep waters between 100~300 m depth. A rare species, vast majority of the known specimens were collected as empty shells. Though the specific feeding ecology is not known for this species, it is almost certainly a carnivorous gastropod preying upon other invertebrates as is typical for its family. A little-varied species and adult shells are instantly recognisable; young shells have much stronger axial ribs than adults. Typical shell length around 80 mm and the largest known specimens exceed 90 mm, though the species can probably attain 100 mm or more. <br />
<br />
This species was named after the Japanese conchologist Mitsuo Chino, who collected most of the seven specimens used for its description. The spiral sculpture is unusual among Manaria species because it is uniform in strength across the whole shell and not alternating between weaker and stronger sections. The lack of axial sculpture at adult body whorl and the large size also makes it distinctive from other Manaria species. The most similar species is perhaps the type species Manaria thurstoni Smith, 1906 from the northern Indian Ocean, but M. thurstoni has a broader shell with stronger axial sculpture; the shell of M. thurstoni is also much smaller and averages at around only 30 mm in length.

Cymbiola imperialis ([Lightfoot], 1786)<br />
VOLUTIDAE<br />
-65 m, By net, Bongao, Tawi-Tawi, Mindanao, Philippines, 2020, 238.0 mm <br />
<br />
The aptly named "Imperial Volute" is a large volutid native to Sulu Sea between the Philippines and Malaysia, characterised by a crown of long spines around the shoulder. A carnivorous and predatory gastropod inhabiting sandy bottoms and feeding on other invertebrate animals, it is found from very shallow waters just below lowtide zone to about 80 m depth. A common species, its showy shell is often sold as souvenir or room decoration, almost all originating from the Philippines. <br />
<br />
Typical specimens exhibit a shell pattern combining lightning-like axial streaks and 3-4 broad spiral bands of irregular dark brown blotches, but some specimens lack the spiral bands entirely -- a form known as f. robinsona (Burch, 1954). The shoulder spines vary in strength and number among individuals, shells without spines have also been found but such specimens are extremely rare. The aperture colouration can also vary from pale yellow to very dark orange. The shell is covered by a layer of thin, brownish periostracum when alive; the periostracum is often glazed over on the ventral side by another layer of transparent calcium carbonate (callus). Typical shell length around 200 mm, very large specimens can exceed even 270 mm. <br />
<br />
Though the overall morphology of C. imperialis resemebles C. chrysostoma (Swainson, 1824), that species is much smaller and typically does not exceed 80 mm in shell length. Cymbiola nobilis ([Lightfoot], 1786) is another broadly similar species, but is easily distinguished by the shell being broader and lacking shoulder spines entirely.

Sinutor incertus (Reeve, 1863)<br />
CALLIOSTOMATIDAE<br />
On beach, Western side of Phillip Island, Victoria, Australia, Leg. Guido T. Poppe, 12.5 mm <br />
<br />
As its name suggests, the "Left-Handed Calliostoma" is a calliostomatid snail whose coiling is normally sinistral, the only member of its family to exhibit this feature. Endemic to Australia, it inhabits moderate depths between 30~300 m from Victoria to south coast Western Australia, including Tasmania. Though the feeding ecology of this species is unclear, it likely lives on cnidarian hosts upon which it feeds as is typical for calliostomatids. Quite a rare species, most specimens have been collected as empty shells beached after storms. The shell carries numerous fine spiral striations, and is covered by a pattern consisting of regularly spaced fine speckles of reddish brown, unfortunately often lost in beached shells (as shown). Typical shell length around 10 mm, very large specimens may reach 15 mm. The unique sinistral coiling renders it unmistakable among all other known calliostomatid species. The obtusely angled, rather convex base is also an unusual character for the family. Originally described in genus Zizyphinus (now synonym of Calliostoma), Sinutor was first established as a subgenus to house this strange species, and then it was raised to a full genus. Some authors still refer it to genus Calliostoma, as C. incertum.

Niso regia Kuroda & Habe, 1950<br />
EULIMIDAE<br />
Trawled in deep water, Off Kweishan Island (Turtle Island), Yilan County, Taiwan, 27.2 mm <br />
<br />
Characterised by a broad orange spiral band over a tall, white shell, the "Regal Niso" is a large eulimid native to the western Pacific where it ranges from Japan to South China Sea. Inhabiting sandy bottoms of rather deep waters around -100~300 m, it is a rare and seldom seen species. Most specimens seem to have been trawled by fishing boats from Taiwan. Though its specific diet is not known, eulimids are parasites of echinoderms and other Niso species feed on sea stars; N. regia likely also does the same. Unlike some other eulimids, the genus Niso is hemiparasitic and is mostly free-living on the seafloor, only attach to hosts when they need to feed. Typical shell length around 25 mm, very large specimens may reach 35 mm. The striking orange pattern is unique among known eulimids and it is therefore an easily recognisable species. It is also the largest species of genus Niso in the western Pacific, which likely inspired the species name.

Retrolucina voorhoevei (Deshayes, 1857)<br />
LUCINIDAE<br />
In muddy sand, Inhambane, Mozambique, 50.5 mm <br />
<br />
An elongate and laterally compressed thin shell with a nearly smooth surface characterises the "Voorhoeve's Lucina Clam", a highly unusual shallow water lucinid ranging from Oman to Mozambique in the Indian Ocean. Though a single record also exists from Algoa Bay in South Africa, the validity of this has been questioned pending further evidence. A very rare species, it has supposedly never been collected alive with all specimens being either beached or dived as empty valves in shallow waters down to about 10 m deep. Live individuals are thought to inhabit sandy bottoms of subtidal waters a little deeper than this, but this requires locating living specimens to confirm. As such, the feeding ecology of this species is not known specifically, but being a lucinid it almost certainly relies on chemosymbiotic bacteria living in specialised cells on the gill for energy. <br />
<br />
Typical shell length around 60 mm, very large specimens may reach 80 mm. A little-varied species, it cannot be mistaken with any other described living lucinids. Previously it was included in genus Eomiltha, but later it was separated into its own genus Retrolucina due to the unusual shell morphology. A close relative was the extinct Retrolucina defrancei (Deshayes, 1857) from Eocene deposits in Paris Basin, France, and R. voorhoevei is considered the sole survivor of this lineage today.

Amygdalum soyoae Habe, 1958<br />
MYTILIDAE<br />
-120 m, Dredged, Off Kagoshima (29°55'N, 127°34'E), Japan, 2000/ii/13, 14.3 mm <br />
<br />
Surely one of the most beautiful mytilids with a 'snowy' pattern of irregular radial white dots on a translucent blue background, Amygdalum soyoae is native to the western Pacific and ranges from central Japan to South China Sea around the Philippines. Though an overall little-varied species, development and details of the white speckling can differ considerably among individuals when looked closely. A rarely seen species, it is instantly recognisable by its shell patterning and can only be confused with the Caribbean species A. sagittatum (Rehder, 1935) with a similar pattern, but the two are so geographically distant that they cannot be mixed when locality data is available. <br />
<br />
It is a filter-feeding bivalve that seems to prefer a very specific habitat of sand, shelly sand, and rubble pockets accumulated on top of hard rocky bottoms between 50~250 m deep -- making it rather difficult to collect by dredging and contributing to its apparent scarcity in collections. Like other Amygdalum species it makes a nest, in this case from mud particles and fine byssus threads. Typical shell length around 15 mm, very large specimens may reach 20 mm. <br />
<br />
The first specimens were collected by the Japanese survey ship (S.S.) Soyo-Maru, which became the namesake of this species. The Soyo-Maru has been passed down through four generations of survey ships (completed 1911, 1955, 1970, and 1994), and have collected many previously undescribed molluscs and other animals from the deep sea around Japan by dredging. Initially it belonged to the Imperial Fisheries Experimental Station, later passed to what is now Japan Fisheries Research and Education Agency.

Neomphalus fretterae McLean, 1981<br />
NEOMPHALIDAE<br />
-2561 m, On the tube of Riftia pachyptila, Tempus Fugit hydrothermal vent field (0.769923°S, 85.911449°W), Galápagos Rift, ROV SuBastian dive #609, R/V Falkor (too) cruise FKt231024, 2023/xi/02, 25.8 mm <br />
<br />
When deep-sea hot vents were first found 2.5 km below surface on the Galápagos Rift in 1977, the largest animals like large vesicomyid clams, mussels, and the giant tubeworm were immediately lionised as icons of these ecosystems. But scientists found much more than these large-bodied symbiotic animals, including a suite of equally unusual but less conspicuous limpets. The largest and perhaps the most puzzling of them was Neomphalus fretterae, which could not be placed in any known suborder -- it was the first representative of the so-called "hot vent clade" of gastropods whose discovery would eventually lead to the establishment of a whole new subclass, Neomphaliones (within which it is now placed in order Neomphalida, superfamily Neomphaloidea, family Neomphalidae). <br />
<br />
Neomphalus fretterae has a limpet-formed shell as adults, but the first whorl after the protoconch is coiled. The white shell is overlaid by a rather thick, semi-transparent, light-brown periostracum which has a near-metallic sheen when wet, making different parts of the shell appear to glow in gold and silver under light. The shell is sculptured by numerous radial ribs, with primary ribs bearing numerous periostracal scales and the secondary ribs mostly smooth. The number of ribs vary greatly among individuals and some shells are almost completely devoid of primary ribs. It is anatomically adapted to filter-feeding using a much enlarged gill, food particles are then passed through a food groove over the right cephalic tentacle into the mouth. Living in dense aggregations near diffuse flow venting either on sulfide deposits or on giant tubeworms, the shell margin is irregular and grows to fit the immediate substrate shape -- this species does not usually travel distances. As is typical for the family Neomphalidae, in males the left cephalic tentacle is enlarged to serve as a penis. <br />
<br />
It is locally abundant at the Galápagos Rift vents but rare at East Pacific Rise sites between 9-21°N where it was subsequently found; as Galápagos vents have rarely been visited in the recent years it has only been collected on a handful of research cruises over four decades. Its known habitats span a depth range between 2400-2700 m deep. Typical shell length around 20 mm, very large specimens can reach 35 mm. It was named in honour of Dr Vera Fretter (1905-1992) of University of Reading, who made very important contributions to the anatomy and functional morphology of gastropod molluscs. Fretter also worked on this species, providing a detailed anatomical description of it.

Conus tisii Lan, 1978<br />
CONIDAE<br />
-350 m, By tangle net, Tinina, Balut Island, Davao Occidental, Philippines, 2023, 73.9 mm <br />
<br />
Ranging from southern Japan to Taiwan to the Philippines, Conus tisii is characterised by a shell with a low domed spire and two darker bands on the body whorl. Widely considered to be one of the "holy grails" of cone collectors, it is an extremely scarce species and one of the most sought-after species of the western Pacific. A carnivorous and predatory gastropod, it inhabits moderately deep waters between 100~400 m deep. <br />
<br />
The shell shape and patterning are both somewhat variable. The overall shell height-to-width ratio though the spire is always distinctly domed. Irregular very dark brown to black blotches occur on the two darker bands on the body whorl but their density and extent of coverage are erratic and vary greatly among individuals, ranging from being completely absent to filling most of the bands. Smaller dark brown dots are sometimes also present just above the shoulder edge, especially in large adults. Due to an abrupt shift in shell growth pattern, the first few whorls protrude from the domed spire as a sharp tip. This is often worn away in mature shells. The base shell colouration is white, but fresh shells typically carry a lilac hue that fades over time. Typical shell length around 110 mm, very large specimens are known to exceed 150 mm. <br />
<br />
It is most similar to Conus kostini Filmer, Monteiro, Lorenz & Verdasca, 2012 with which it was long confused. Compared to C. tisii, the shell of C. kostini is typically much lighter and more slender with a higher domed spire. The dark brown blotches on C. kostini is usually lighter-coloured than in C. tisii, and they are less defined to the main bands, often present extensively around the shoulder and extending on to the spire which is never the case in C. tisii. <br />
<br />
This species was first discovered as two trawled specimens off Taiwan and was then described by the eminent Taiwanese conchologist Tzu-Chiao Lan, who served as the President of the Malacological Society of Taiwan until his passing in 2004. The origin of the specific epithet "tisii" is puzzling. An etymology was not given for it in the description, though a widely alleged notion is that it is based on the English pronouciation of the alphabets "T.C." (initials of Lan's first name; Lan seldom used his first name in full and was usually referred to as T.C.). The rumour goes that Lan was under pressure from members of his malacological society that this large, spectacular new species should be named after him, but he also wanted to describe it himself. Though not prohibited in the International Code of Zoological Nomenclature, naming a species after oneself is broadly thought to be unethical and unprofessional. Perhaps using a perplexing name like "tisii" without a specific etymology satisfied his society while also allowed him to avoid clearly naming it after himself? Perhaps we will never know for sure.

Chytra kirkii (Smith, 1880)<br />
PALUDOMIDAE<br />
Lake Tanganyika, Hasole, Tanzania, 18.6 mm <br />
<br />
One of about 70 species of paludomid gastropods that diversified in both morphology and ecology after colonising Lake Tanganyika, the shell of Chytra kirkii has a remarkable resemblence to marine trochoids. This shape was of course convergently evolved from trochoids, and despite this great divergence of shell form from typical paludomids their gross anatomy appears to be strikingly similar. It is restricted to shallow to moderate depths in Lake Tanganyika between about 10~100 m deep, where it is a herbivorous grazer. Although not uncommon in the lake it is a rarely seen species due to the low availability of material from there. Both inner and outer lips of the aperture thickens at maturity, a feature setting it apart from many trichroid families such as Trochidae and Calliostomatidae. Living animals carry a spiral, dark brown, corneous operculum. Typical shell diameter around 20 mm, very large specimens may reach 30 mm. This species was named after Sir John Kirk (1832-1922), a British physician and naturalist who collected many new species of freshwater animals from East Africa. Although the first specimens of this species were not collected by Kirk, it was named to honour his work.

Lyria cassidula (Reeve, 1849)<br />
VOLUTIDAE<br />
-40 m, Dived on sand and rubble bottom, Shizuoka Prefecture, Japan, 31.1 mm <br />
<br />
The "Helmet Lyria" is a small volutid endemic to central and southern Japan, with a very robust shell ornamented with weak axial ribs. A carnivorous and predatory gastropod feeding on other invertebrate animals, it typically inahabits sand to rubble bottoms of shallow depths around 10~30 m deep but can rarely be found as shallow as the low tide line and as deep as 80 m. Overall an uncommon species, empty shells are often beached but it is surprisingly difficult to find live-collected specimens with operculum. One reason for this is that live specimens are simply rarely seen, but another reason is that the animal of Lyria will easily discard the posterior part of its foot -- where the operculum is attached to -- when attacked by a predator. This is thought to be an autotomic behaviour with the aim to distract the predator, and is also known from a number of other gastropod groups. Given time the foot will regenerate, sometimes with a new operculum which is typically deformed compared to the original one. As such, many live animals do no longer possess an operculum. <br />
<br />
The shell form is somewhat variable in terms of the density of axial ribs, as well as the spire height. Colouration and patterning of the shell are extremely variable, though always with lighter background overlaid by numerous spiral lines and irregular, darker brown patches. The aperture colouration can range from white to deep orange. A subspecies name, L. c. pallidula Habe, 1962, was given to specimens with much lighter colouration that are usually from deeper depths, but this likely represents a mere deep-water form. Typical shell length around 30 mm, extremely large specimens may reach 45 mm.

Neopilina galatheae Lemche, 1957<br />
NEOPILINIDAE<br />
-2461 m, On glassy basalt on the top of a half-collapsed lava tower (0°48.2986’N, 86°13.1732’W), Galápagos Rift, Taken by suction sampler on ROV SuBastian dive #603, R/V Falkor (too) cruise Fkt231024, 2023/x/28, 26.8 mm <br />
<br />
The legendary discovery of the first living monoplacophoran mollusc – Neopilina galatheae – trawled by the Galathea expedition from 3570 m deep off Costa Rica in 1952, was a sensational event in zoology of the 20th Century. This first finding of a whole class thought to be extinct since the Devonian (about 375 million years ago) made it one of the most famous “living fossils”. Every museum has a model of it, and it is mentioned in every biology course. But how many real specimens are there? Turns out, there are only 13 confidently identified specimens (and one fragment) collected on three occasions, until the specimen shown here was collected. <br />
<br />
With 10 specimens, the Galathea trawl was a“jackpot”, as follow-up cruises set to obtain further specimens near the type locality returned empty handed except the Vema expedition, which successfully collected a single specimen from 3718 m deep in 1958. Then, three live specimens turned up off Baja California, Mexico in 1959 where they were trawled between 2781–2809 m deep, plus a fragment from a grab sampler at 1828 m. The specimen shown here was serendipitously collected from glassy basalt on the Galápagos Rift in October 2023, the first specimen to be collected in 64 years and the first time it was observed live on the seafloor. This finding extends its distribution range from Baja California, Mexico to Galápagos Rift in very deep waters between 1828-3570 m depth on both hard and soft substrata. Monoplacophoran molluscs are thought to be detritivores, though N. galatheae apparently also feeds on xenophyophores (giant protists). <br />
<br />
Typical shell length around 30 mm, the largest specimen known is 37 mm, making it the largest living monoplacophoran. Some key morphological characteristics of this species are: five pairs of gills, well-developed postoral tentacles, apex being close to the anterior edge of shell, and the irregular concentric shell sculpture. It is the type species of genus Neopilina, which received its name for close morphological resemblence to the extinct tryblidiid monoplacophoran Pilina that lived between Ordovician and Silurian. The specific epithet was dedicated to the Danish HDMS Galathea whose expedition first recovered the species. <br />
<br />
Read more for free in my preprint paper here: Chen C*, Jamieson JH (Preprint). In situ observation and range extension of the first monoplacophoran Neopilina galatheae. bioRxiv, https://doi.org/10.1101/2023.11.08.566290

Panopea bitruncata (Conrad, 1872) <br />
HIATELLIDAE<br />
-1 m (-3.5 ft.) deep in sticky mud at extreme low tide (-0.3 m / -0.9 ft.), Dug up in mud flats to the northwest (gulf side) of Islamorada Key Bridge, Florida Keys, Florida, U.S.A., 1971/xii/04, 183.3 mm <br />
<br />
The "Atlantic Geoduck" is a very large hiatellid clam living buried very deep in soft mud, from where it filter-feeds by extending a very large, elongate, fleshy siphon above the sea bottom. Found in shallow to moderate depths between extreme low tide to at least 50 m deep on the Atlantic coast of North America, its confirmed range is from Chesapeake Bay around Virginia to Florida (where most specimens have been found) to Texas in the northern Gulf of Mexico. This may extend further southwards, as there are unconfirmed records from Yucatán Peninsula in Mexico. <br />
<br />
Unlike the better-known congener inhabiting the Pacific coast of North America -- the "Pacific Geoduck" Panopea generosa Gould, 1850 -- which is very common and widely used for seafood, living P. bitruncata is very rare. Until 1960's when definitive live-taken speciemns were collected, the recent material was only known from disarticulated empty shells and some authors considered it to be extinct. It is however a common constituent of Pliocene formations on the eastern U.S.A. such as at the Caloosahatchie, Shell Creek and Alligator Creek formations. <br />
<br />
For years whether the Pliocene fossils and the living individuals belong to the same species was debated, finally settling on the agreement that they are conspecific. There is some evidence that adult clams are unable to re-burrow once they are dislodged on to the seafloor from storms or other factors. Typical shell length around 150 mm, very large specimens can exceed 220 mm.

Calliostoma bellatrix Willan, 2002<br />
CALLIOSTOMATIDAE<br />
Trawled, Torres Strait, Australia, 38.5 mm <br />
<br />
A broad trochoid shell ornamented with two spiral rows of strong beads, one at and another just above the suture to generate a 'double-keeled' impression, makes the "Bellatrix Top" distinct from other described calliostomatids. Ranging from northern Australia through Timor Sea to southern Indonesia, it inhabits soft bottoms on the continental shelf between around 200~400 m deep. Though its specific diet is unknown, it is most likely a carnivorous grazer feeding on other invertebrate animals such as corals and sponges, as is typical for other calliostomatids. Typical shell diameter around 35 mm, very large specimens may reach 45 mm. <br />
<br />
The shell surface is irregularly marked with reddish brown axial streaks, and is strongly iridescent so that under strong light the shell appears to glow. This was the inspiration for its name -- Bellatrix, the third brightest star in the constellation of Orion. The broad, 'double-keeled' shell plus the lack of significant sculpture on most of the subsutural ramp are sufficient to distinguish it from other Calliostoma species. Though currently placed in a different genus, Bathyfautor coriolis Marshall, 1995 from New Caledonia is morphologically similar -- though that species has a much narrower shell with much weaker peripheral keels.

Cirsotrema bennettorum García, 2000<br />
EPITONIIDAE<br />
-300 m, Dredged, Grand Passage, New Caledonia, 26.9 mm <br />
<br />
Known only from moderately deep waters between 200-500 m depth off New Caledonia, the "Bennett's Wentletrap" is a highly characteristic epitoniid with a tall turbinate shell shape ornamented by dense blade-like axial lamellae. Some of these lamellae are thickened as strong varices, although the number and frequency of such varices are very variable among individuals and also among different whorls within the same individual. Otherwise the shell is little-varied and always white. On adult shells the first few whorls are almost always lost. Though the feeding ecology is unknown, it is most likely a parasitic gastropod living on and around sea anemone hosts upon which it feeds, like other epitoniids. Typical shell length around 25 mm, very large specimens may approach 35 mm. A rare species, most specimens known have been dredged on sandy bottom. Its shell morphology and sculpture are unique among known epitoniid species, and it is thus easily identified. It was named in honour of Jo (and Charles George "Rusty" Bennett, shell collectors from Florida, U.S.A.

Oocorys tosaensis Habe & Azuma, 1959<br />
CASSIDAE<br />
-400~600 m, Trawled, Pratas Islands, South China Sea, 33.2 mm <br />
<br />
Characterised by a thick, solid shell with a narrow, open umbilicus and coarse spiral ribs, Oocorys tosaensis is a deep-water cassid ranging from the southern half of Japan to Taiwan to South China Sea. Used to be an extremely rare and virtually unobtainable species, in the recent years some specimens have been trawled off Pratas Islands in the South China Sea. Nevertheless, it remains a rare species and live-collected specimens are especially hard to comeby. Inhabiting sandy to muddy bottoms between 200~600 m deep, it is a carnivorous and predatory gastropod feeding primarily on echinoderms. Typical shell length around 30 mm, very large specimens can exceed 40 mm. When alive the shell is covered by a layer of semi-transparent, greenish brown periostracum. Though some authors have considered it to be a junior synonym of the very variable Oocorys verrillii (Dall, 1889), this is unlikely due to the extremely consistent shell morphology of O. tosaensis -- most notably the open umbilicus that is missing in O. verrillii. Though once placed in the genus Hadroocorys, this is now considered to be a junior synonym of Oocorys.

Euhadra senckenbergiana (Kobelt, 1875)<br />
CAMAENIDAE<br />
Mt. Norikura, Takayama, Gifu Prefecture, Japan, 51.0 mm <br />
<br />
One of the most spectacular native landsnails of Japan, Euhadra senckenbergiana or the "Kuroiwa's Euhadra" as it is locally known, is widely distributed in Honshu Island from the Tohoku Region to Kyoto Prefecture; the centre of distribution is in central Honshu across Ishikawa, Fukui, Gifu, Nagano, and Niigata Prefectures. A rather rare species inhabiting forest floors, it prefers dense primeval forests and is a herbivorous grazer feeding on a variety of plant matter. Like many Euhadra species it can be very variable in colouration, the specimen shown is a typical specimen from highlands of the central Honshu region with rather irregular, thick axial growth lines overlaid with intermittent yellowish lines that form a flame-like pattern across the shell surface. Even within the same population, the pattern development can vary greatly. With an average shell diameter of 50 mm and the largest specimens reaching 60 mm, it is the second largest landsnail species native to Japan only after Euhadra awaensis (Pilsbry, 1902) which can exceed 65 mm. Its Japanese vernacular name is dedicated to the Japanese naturalist Hisashi Kuroiwa (1858-1930) who extensively studied the wildlife of Okinawa. <br />
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Though several subspecies names have been proposed for various populations with different morphological characteristics, the status of those names are mostly in a state of flux. For example, Euhadra awaensis was once considered a subspecies of E. senckenbergiana, but is now generally accepted as a separate valid species. The name E. s. ibukicola Pilsbry, 1928 was proposed for a smaller population narrowly distributed only in Mt. Suzuka and Mt. Ibuki, but is now thought to be a mere junior synonym. One subspecies that is still considered to be valid by most is E. s. notoensis Kuroda & Teramachi, 1954 inhabiting plains of the northern Honshu from Ishikawa to Niigata Prefectures, which has a brighter background colouration and lacks the flame-like patterns.

Chicoreus ramosus (Linnaeus, 1758)<br />
MURICIDAE<br />
Dived in shallow water, Sandakan, Sabah, Malaysia, Borneo Island, 230.2 mm <br />
<br />
The "Ramose Murex", also known as the "Branched Murex", is the largest living muricid species known with a shell length averaging around 200 mm and the largest specimens exceeding even 330 mm. A very widely-distributed species commonly seen across the entire Indo-West Pacific, it is found from South Africa to Japan to Australia, including Red Sea. The solid shell can be very variable in spine and siphonal canal development, from extremely elongate to short and stubby. Adult shells are typically white with some patches showing brownish spiral lines, but juveniles can be very colourful ranging from white to bright orange to almost completely black. The inner lip is usually brightly coloured, commonly pink or orange. <br />
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A carnivorous and predatory gastropod, it inhabits sand or rubble bottoms near coral reefs from low intertidal down to about 30 m deep and feeds on other molluscs, chiefly bivalves. As such, it is often considered a pest of bivalve aquaculture such as oysters or pearl oysters along with fellow muricids. Due to its rather large size and edible flesh, it is a important species for fisheries in some countries like India. The shell is commonly sold as decoration and can be easily found around the globe, though large, specimen-grade shells are surprisingly difficult to come by. It lays large clusters of about 400 eggs, each about 20 mm in length.

Pyrulofusus melonis (Dall, 1891)<br />
BUCCINIDAE<br />
-300 m, Trawled on mud, South of Pribilof Islands, Bering Sea, Alaska, U.S.A., 2010/vii, 127.2 mm <br />
<br />
Characterised by numerous slightly wavy axial ridges crossing with numerous very fine spiral lines, the "Melon Shaped Whelk" is a large cold-water buccinid native to the Bering Sea. Like many Bering Sea buccinids, it inhabits a very wide bathymetric range from shallow subtidal waters around 20~30 m to over 400 m deep; most specimens are trawled between 100~300 m deep. As is typical for genus Pyrulofusus, it is a direct developer that hatch as crawling juvenile snails from very large egg cases around 40~50 mm in diameter. <br />
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Though supposedly common in its natural habitat, it is a uncommonly collected species due to its inaccessible range in the Bering Sea. A carnivorus and preadatory snail, it feeds mostly on other invertebrate animals. The shell is somewhat variable in terms of the density of axial ridges, as well as the height-to-width ratio. The aperture colour can be yellow or white, fresh specimens carry a purple hue which unfortunately quickly fades. Typical shell length around 120 mm, very large specimens can reach 160 mm. The unique undulated shell surface from the irregular, wavy ridges serves as the key character that immediately distinguishes it from other congeners.

Stirpulina ramosa (Dunker, 1882) <br />
CLAVAGELLIDAE<br />
Shizuoka Prefecture, Japan, 98.6 mm <br />
<br />
A truly ecccentric and extraordinary bivalve, Stirpulina ramosa is a 'watering-pot' clavagellid that during development stops growing its bivalved shell and abruptly switches to growing a calcareous tube. Although an array of other superficially similar genera such as Brechites and Nipponoclava are known in the superfamily Clavagelloidea, recent researches have revealed that the bizarre life style of building an adventitious tube and living buried in the sand in fact evolved twice within the superfamily Clavagelloidea, once in Clavagellidae and once in Penicillidae. All other such genera belong to the Penicillidae radiation, and Stirpulina ramosa is the only extant member of the genus. This makes it the only surviving endobenthic tube-dwelling clavagellid in the world, a remnant species from Late Cretaceous and a "living fossil". All other living clavagellid species live a sessile life cemented to hard substrates and do not live buried in sand. A clear difference from the penicillids is that it only has the left valve cemented to the calcareous tube, whereas all tube-building penicillids have both valves cemented. The right valve remain free and mobile within the tube. Another difference is that the 'watering-pot' end of the tube consists of bifurcating tubules, a feature not seen in the 'watering-pot' of penicillids. <br />
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An endemic species of Japan inhabiting sand and gravel bottoms -50~200m deep south of Chiba Prefecture, it is a filter-feeder and the tip of its tube is always protruded slightly from sand to access sea water. A very uncommon species, usually only shattered empty tubes are collected; live-collected specimens are extremely scarce. The only recorded specimen with soft parts preserved was housed in the collection of Emperor Shōwa Hirohito, and this was dissected by the eminent malacologist Prof. Brian Morton in order to reveal the anatomical differences with penicillids. Typical length of the adventitious tube around 70mm, extremely long tubes may exceed 100mm.

Amoria subfossilis Bail & Limpus, 2011<br />
VOLUTIDAE<br />
Trawled, Off Swain Reefs, Queensland, Australia, 107.4 mm <br />
<br />
The "Subfossil Volute" is a poorly known volutid that has so far only been found off Swain Reefs in Queensland, Australia. It is a very rare species and all known specimens were supposedly trawled in deep water and were found as empty shells, hence the name. The characteristic golden zigzagged axial pattern and the yellowish cream background colouration are typical of subfossil volutids and suggest these shells have been dead for quite some time, although the exact time is unclear. It has been hypothesised as an extinct species, but it remains possible that a living population exists but has simply not been sampled. Given this situation, we know nothing about its ecology and true habitat, though it is almost certainly a carnivorous and predatory gastropod like other volutids. Typical shell length around 100 mm, very large specimens may approach 120 mm. <br />
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Among living Amoria it is most similar to A. jansae van Pel & Moolenbeek, 2010 which also occurs in Queensland. The two species can be distinguished based on A. subfossilis having a much wider shell with a stronger and sharper flaring of the outer lip. Typically the shell patterning of A. jansae is much darker in colouration, but this is most likely due to the shells of A. subfossilis fading rather than a real difference between the two species. They are both representatives of the subgenus Cymbiolista, which some consider to be a mere junior synonym of Amoria.

Lyria leslieboschae Emerson & Sage, 1986<br />
VOLUTIDAE<br />
-10~15 m, Dived, Off Masirah Island, Oman, 2020/xii, 89.9 mm <br />
<br />
Characterised by a high-spired shell with evenly dotted, closely spaced axial ribs and a diffused flame-like axial pattern, the "Leslie Bosch's Lyria" is a volutid endemic to Oman where it is only known from Masirah Island. Like many Omani mollusc species, it was first discovered by Dr Donald Taeke Bosch (1917-2012) and Eloise Bosch (1919-2016) who authored the book "Seashells of Oman" (1983). Donald Bosch was an American medical officer and Eloise Bosch was a teacher, and since they arrived in Oman in 1955 they became active as amateur conchologists, finding over 20 mollusc species new to science. <br />
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Lyria leslieboschae was discovered in January 1985 beached on the eastern side of Masirah Island, a total of four empty beached shells were sent to the American Museum of Natural History for study and subsequently described in 1986 by the malacologists Dr William Keith Emerson (1925-2016) and Walter Elmer Sage III (1949-1995). Named after Leslie Bosch, daughter-in-law of Donald and Eloise Bosch, this exquite species dissapeared for over three decades since Donald and Eloise Bosch retired -- until the recent reignition of collecting activities in Oman around 2020 by a few conchologists which led to the finding of at least a couple dozens of specimens. Nevertheless, it remains an extremely rare and sought-after species today and it has still only been found as empty beached shells or crabbed in shallow waters. Its true habitat remains undiscovered, but given most specimens have been found beached after severe storms, it likely inhabits moderate depths over 30 m deep off eastern Masirah Island. Its exact diet is not known, but it is probably a carnivorous and predatory gastropod like other volutids. Typical shell length around 90 mm, very large specimens can approach even 130 mm. <br />
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Though it is difficult to confuse with other Lyria species, it is morphologically closest to Lyria lyraeformis (Swainson, 1821) which has a more southernly distribution between Somalia and Mozambique. The two species can be easily distinguished based on the following key features: 1) the protoconch of L. leslieboschae is blunt and lacks a sharp calcarella characteristic of L. lyraeformis; 2) the outer lip of adult L. leslieboschae is sigmoid and ends in a narrow posterior canal but is simple in L. lyraeformis; 3) the flame-like diffused axial pattern of L. leslieboschae is lacking entirely in L. lyraeformis.

Cardilia semisulcata (Lamarck, 1819)<br />
CARDILIIDAE<br />
Shizuoka Prefecture, Japan, 18.7 mm <br />
<br />
An unusual shell morphology with very inflated and higher-than-long valves, Cardilia semisulcata belongs to the little-known bivalve family Cardiliidae. Despite being a widely distributed species in the Indo-West Pacific with records ranging from central Japan to Queensland, Australia to Oman, it is a very rare species virtually only seen as disarticulated, beached shells after storms. Even such single valves are scarce and are highly prized by beachcombers, few live-taken specimens with both valves are known. <br />
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Virtually nothing is known about its ecology, except that it lives buried in sand or mud between about -5~30 m deep. If the placement of Cardiliidae in Mactroidea is indeed correct (as is suggested by the hinge morphology) this would imply that cardiliids are most likely filter-feeders, though this requires further evidence. The holotype was supposedly collected from South Australia, but as it has never been seen south of New South Wales in Australia, this is likely erroneous. Typical shell length around 15 mm, very large specimens may reach 30 mm. <br />
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Due to superficial similarity to glossids with the strongly raised umbo, it was originally described as Isocardia semisulcata (Isocardia now a junior synonym of Glossus) in Glossidae. In 1835 the French paleontologist and malacologist Gerard Paul Deshayes (1797-1875) recognised its uniqueness and placed it in a new genus, Cardilia. Today Cardilia remains the only genus in Cardiliidae, and despite four living and 11 fossil species being recognised it remains one of the least studied bivalve families. In Japan it is known as "Kisa-Gai" (literally meaing "Elephant Shell"), due to the coiled umbo of each single valve vaguely resembling elephant noses.

Aporrhais elegantissima Parenzan, 1970<br />
APORRHAIDAE <br />
-30~50 m, Trawled, Off Dakar, Senegal, 58.7 mm <br />
<br />
Ranging along the western African coast between Mauritania and Angola, the "African Pelican's Foot" is a medium-sized aporrhaid snail typically carrying four spine-like digitations on the adult shell. A detritivorous gastropod species found on soft bottoms of moderate depths between 30~200 m deep, it is a common species and most specimens originate from Senegal. Though it has supposedly also been recorded from Morocco and Mediterranean Sea, these are not associated with reliable specimens and require further evidence to confirm. Two forms are known, with the smaller, short-spined form (typical shell length around 30 mm) being much more abundant than the larger, long-spined form (shown, typical shell length around 50 mm). Very large specimens of the latter form may reach 80 mm. The reason behind these two morphologically separable forms is unclear -- although sexual dimorphism as well as impacts of salinity and temperature has been suggested as possible explanations, the possibility that these represent two independently evolving lineages cannot be discarded at this time. <br />
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Ever since its description it has been confused with the closely related A. pesgallinae Barnard, 1963, with the two being considered synonyms since 1976. However, in a 2019 paper by Ulrich Wieneke and Virgilio Liverani it was clarified that A. pesgallinae is actually a distinct deep-water species endemic to 300~450 m deep off Namibia, reinstating A. elegantissima as a separate species in its own right. The two species differ in shell morphology where A. pesgallinae has a larger, wider spire with more compressed spire angle and stronger keels on the last whorl, more clearly sickle-shaped base in the abaxial digits, and a white colouration instead of brown, when compared to A. elegantissima. Both of these species are thought to hybridise with A. senegalensis Gray, 1838, producing the few known shells combining characteristics of both parent species.

Scutellastra kermadecensis (Pilsbry, 1894)<br />
PATELLIDAE<br />
Lowtide on rock, Raoul Island, Kermadec Islands, New Zealand, 1967/vii, 80.3 mm <br />
<br />
The "Kermadec Limpet", as its name suggests, is a pattelid true limpet endemic to the Kermadec Islands of New Zealand. A key highlight of this species is its size -- with an average shell length around 120 mm and giant specimens said to exceed even 170 mm, it is one of the largest species of extant true limpets. <br />
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Because it is so different and so much larger than any other true limpets known from around New Zealand and Australia, shortly after its description fierce debate ensued regarding its type locality. The malacologist John William Brazier (1842-1930) believed it was extremely unlikely that such a large limpet had remained undiscovered in the Kermadecs despite known expeditions already visited these islands, he hypothesised that this species is more likely to originate from South Africa, where many species of large-sized true limpets are known. Fortunately, the original locality of Kermadec Islands could be verified by Thomas Federic Cheeseman (1845-1923), curator of the Auckland Museum in New Zealand who collected the first specimens (including the type series), testifying that these limpets were numerous on the rocky shores surrounding a number of islands in the Kermadecs and that previous expeditions likely missed them because they landed in sandy beach instead of rocky shores. <br />
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Indeed, research visits to the Kermadecs later proved that this species is very common on these islands; but as since 1977 the Kermadecs have become a nature reserve with collections strictly forbidden, this species is now rarely seen in private collections. The shell is characterised by numerous strong radial ribs, although most large specimens have the dorsal surface completely eroded away. Younger individuals have a narrower shell with darker colouration (as shown), which then becomes broader, more rounded in shape, and lighter in colour with time. A herbivorous grazer, it feeds on algae growth on the rocky shore and inhabits very shallow waters in the lower intertidal.

Inquisitor elegans Bozzetti, 1993<br />
PSEUDOMELATOMIDAE<br />
-40~50 m, Trawled, Off Colochel, Tamil Nadu, India, 2023/i, 70.0 mm <br />
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A peculiar shell morphology with a broad, rounded subsutural ramp and a domed spire characterises the "Elegant Inquisitor", a handsome and rarely seen pseudomelatomid "turrid" snail native to the northern part of Indian Ocean. First described from four specimens trawled off Ras Hafun, Somalia, it was later also found off India; although it has not been recorded with certainty between these two localities, this is likely linked to biased sampling effort instead of representing a truly disjunct distribution. Most specimens have been dredged or trawled in moderate depths between 50~200 m deep on sandy bottoms. <br />
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Anterior to the prominent subsutural ramp, the shell carries a latticed sculpture where the axial ribs are much stronger than spiral ribs and is coloured by two to three broad spiral bands of reddish brown. These features make its shell not only instantly separable from other Inquisitor species but also quite attractive, and with rarity added on top it has become a much sought after species. Though almost certainly a carnivorous and predatory species feeding on invertebrate animals, no information is available regarding its feeding ecology. Typical shell length around 50 mm, very large specimens like the one shown can exceed 70 mm.

Marginellona gigas (von Martens, 1904)<br />
MARGINELLONIDAE<br />
-400 m, Trawled on muddy bottom, Spratly Islands, South China Sea, 2010, 193.9 mm <br />
<br />
A species famed for its convoluted taxonomic history, the "Pratas Volute" is now placed in neither Volutidae nor Marginellidae but instead in Marginellonidae. Initially described from a single specimen collected from 805 m deep off Nicobar Islands by the German Valdivia Expedition (1898-1899), certain similarities to volutids were noted but it was placed in Marginellidae largely based on the strange radula morpholology with a very wide central teeth bearing numerous cusps, similar to some radula known from other marginellids. Then later in 1967 the American malacologist Herald A. Rehder (1907-1996) named the same species again as Sigaluta pratasensis Rehder, 1967 based on specimens dredged by the American research ship "Albatross I" in 1907-1909 off Pratas Islands, South China Sea. Apparently unaware of von Martens' earlier work, Rehder only examined the shell morphology and placed it in Volutidae. This started a long confusion on whether this species should be placed in Marginellidae or Volutidae -- although radula features indicated the former, the very large size of this species with shell length averaging at around 120 mm being monstrous for Marginellidae and more typical for Volutidae. <br />
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In 1991 malacologists "Jerry" Harasewych and Yuri Kantor examined newly obtained specimens in detail, finding anatomical characters like the presence of a buccal caecum and a simple stomach that supported its placement in Marginellidae. So there it was sitting in subfamily Marginelloninae under Marginellidae until 2019, when the first molecular phylogeny to investigate it surprisingly found it to be sister to a group containing both Marginellidae and Cystiscidae. As such, Marginelloninae was moved outside of Marginellidae as a new family-level group, Marginellonidae. Currently Marginellonidae houses this species together with Afrivoluta pringlei Tomlin, 1947, another large-sized species found off South Africa that was also once placed in Volutidae. <br />
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Now we know its distribution to range from east Indian Ocean off Nicobar Islands to East China Sea, though it is by far most abundant in the South China Sea off Pratas Islands where it is a common fisheries by-catch between 300~1000 m depth. A carnivorous and predatory gastropod feeding on other invertebrate animals, it is found on both sandy and muddy substrates. Though generally instantly recognisable, specimens do vary in spire height and therefore the shell height to width ratio. Individuals mature at drastically different sizes, ranging from dwarf individuals maturing (with thickened lip) at around 60 mm and giants at over 210 mm. At its maximum size, it is by far the largest of all "marginelliform" gastropods (families Marginellidae, Cystiscidae, Marginellonidae). A few albino specimens with completely white shells have been found.

Conchocele koyamai Habe, 1981<br />
THYASIRIDAE<br />
Shizuoka Prefecture, Japan, 37.8 mm <br />
<br />
Characterised by a peculiar 'stepped' shell form where two well-defined posterior folds and two strong ridges divide each valve into five distinct regions, the "Koyama's Cleftclam" is a thyasirid bivalve endemic to central Japan on the Pacific side of Honshu Island with a range approximately between Wakayama Prefecture and Chiba Prefecture. The holotype is an empty left valve collected by in prawn dredge off Cape Shionomisaki, Wakayama Prefecture measuring 21.0 mm in length; for a long time this was thought to be the only known specimen. <br />
<br />
Though a few articulated specimens have been collected in recent years by dredges or deep-diving in sandy bottoms between 50~100 m deep, it remains an extremely rare species and highly sought after by Japanese collectors. A number of empty, disarticulated valves have even been beached-collected in Chiba Prefecture but such discoveries are also very scarce. No information is available on its ecology, and therefore its feeding habits are unknown; though it likely hosts sulfur-oxidising bacteria as symbionts on its gill like may other thyasirid species. Typical shell length around 25 mm, very large specimens like the one shown here can exceed 35 mm. <br />
<br />
Although described as a member of genus Conchocele, many of its conchological features do not align well with typical Conchocele. These include 1) the presence of a well-definied second posterior fold (termed submarginal sulcus), 2) numerous conical granules on the shell surface, and 3) numerous radial striations on the inner surface of the shell. As such, the need to make a new genus to house this species has been discussed but not yet realised. Due to these features, it cannot be confused with any other known thyasirid species. Its namesake was not clearly stated in the original description, but is most likely the Japanese conchologist Yasuo Koyama who was based in Wakayama Prefecture and was the first to collect many species (likely also this one).

Niso hendersoni Bartsch, 1953<br />
EULIMIDAE<br />
-27 m (-90 ft.), Dredged, Off St. Augustine, Florida, U.S.A., Leg. Michael Cahill, 1970's, 39.2 mm <br />
<br />
The "Beautiful Niso" is a highly unusual eulimid with a striking pattern on the shell, unlike most species which lack pattern altogether. A rare species and among the most coveted collector's item in the family, it ranges between North Carolina and Florida, U.S.A. and inhabits sandy bottoms of moderate depths around 20~200 m deep. Eulimids feed exclusively on echinoderms which they parasitise, the genus Niso is known to parasitise sea stars and N. hendersoni probably does the same. Like other species of Niso, it is most likely hemiparasitic and spends most of its time free-living and only attach to the host when feeding. Typical shell length around 25 mm, very large specimens may reach even 45 mm. <br />
<br />
It was named in honour of John Brooks Henderson Jr. (1870-1923), an American conchologist who was associated with Smithsonian Institute and carried out hundreds of dredges off Florida on his private yacht "Eolis", collecting numerous species undescribed at the time -- including this one. Morphologically it is very similar to its Pacific sister species Niso splendidula (Sowerby I, 1834) which ranges between Gulf of California to Ecuador. Though the two species have very similar pattern, the spiral bands on N. splendidula carry more closely spaced axial lines and darker in colouration. Due to the large size and the characteristic shell pattern, N. hendersoni cannot be confused with any other known eulimid species.

Fulgoraria elongata Shikama, 1962<br />
VOLUTIDAE<br />
-550 m (-300 fms.), Trawled, Off Chōshi, Chiba Prefecture, Japan, 1961, Ex-Coll. Tokio Shikama, 128.6 mm <br />
<br />
Characterised by an exceptionally narrow and thin shell for the genus, the "Elongate Japanese Volute" is a volutid only known from a small area east off Chiba Prefecture, Japan. A carnivorous and predatory gastropod, it inhabits sandy to muddy bottoms of rather deep waters around 200~800 m depth (majority from below 500 m) and most likely feeds on other invertebrate animals as is typical for members of genus Fulgoraria. Perhaps the rarest volute found around the Japanese Archipelago, only several dozens of specimens are known and mostly with broken lips due to its thin and frail shell structure. Its rarity can be partly attributed to its narrow range and the deep, inaccessible habitat, though it does also appear to naturally occur in low densities. The Japanese malacologist and paleontologist Tokio Shikama (1912-1978) who named it accumulated a number of specimens over the years, many of which later ended up in other collections. <br />
<br />
The shell surface is sculptured by about 20 axial folds per whorl, strongest at the early teleoconch whorls and diminishing with growth. Typically, a sparse and irregular zigzagged 'lightning' axial pattern is present on the teleoconch whorls. Two to three weak columellar folds are present, though only one may be clearly visible from the aperture. Typical shell length around 150 mm, very large specimens are known to reach even 200 mm. This species is often confused with the tall-spired form of the much more common Fulgoraria kaneko Hirase, 1922, not because the two species are similar morphologically but because specimens of F. kaneko have been illustrated erroneously under the name of F. elongata in key identification guides for the group like "Volutes" (1992) by Poppe & Goto. Fortunately, this was corrected in the "Conchological Iconography" of Fulgorariinae by Pilsbry & Olsson (1954). The real F. elongata is much closer to the F. megaspira (Sowerby I, 1844) complex, but is distinct in having an exceptionally elongate and thin shell, as well as the much deeper habitat depth.

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