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Dr. Chong CHEN

Dr. Chong CHEN

Deep-sea biologist. Malacologist. Evolutionary biologist. "Mollusc collector", photographer.

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The C. Chen Collection: “Kogkhulion”

“Kogkhulion” (Greek: “Conch”) is a photographic reference to world molluscs using specimens from the C. Chen Collection; continually updated. Mouse-hover over an image will display the scientific name, clicking/tapping reveals the full image with a detailed species account. For a searchable version, click here.

Bolma johnstoni (Odhner, 1923) <br /> TURBINIDAE<br /> -90~120m, Trawled, Off N'zeto (aka. Ambrizete), Zaire, Angola, 48.4mm <br /> <br /> Bolma johnstoni is a stunning turbinid characterised by a well-developed, near-black basal callous which makes it unforgettable and unmistakeable. The shell surface carry scaly sculpture and a single row of rather long spines, the operculum is an attractive reddish-brown coloured one with a granulose central area. A famous endemic species of Angola, it is a rare species due to its restricted distribution and is much sought-after by collectors. It inhabits rather deep water around -70~120m, and although no reliable data exists regarding its detailed feeding behaviours it is almost certainly a grazer. Typical shell diameter including spines around 40mm, very large specimens may exceed 50mm. In the original description it was placed in the genus Astraea, and later moved to Bolma, its current genus. On dealers' lists and collection databases it is quite often misspelt as "Bolma johnsoni" (missing a "t" in the specific epithet).
Perotrochus pseudogranulosus Anseeuw, Puillandre, Utge & Bouchet, 2015 <br /> PLEUROTOMARIIDAE<br /> -300m, Trawled, Off Nouméa, New Caledonia, 2011, 41.0mm <br /> <br /> Perotrochus pseudogranulosus is a recently described medium-sized slit shell, previously confused with P. caledonicus Bouchet & Métivier, 1982. Due to the well-known existence of a "smooth" and a "pustulose" form with apparently no intergrades, there has been a long suspicion that Perotrochus species from around New Caledonia, previously all attributed to P. caledonicus, might actually be a species complex of at least two species. Indeed, an investigation using both morphology and molecular sequencing of the COI barcoding gene revealed in 2015 that the two were distinct species. The "smooth" form with unbeaded to weakly beaded spiral ribs but lacking in significant pustulation matches the type series of P. caledonicus, whereas the "pustulose" form with strongly beaded ribs is a separate species described as P. wareni Anseeuw, Puillandre, Utge & Bouchet, 2015. Surprisingly however, a further previously undescribed species was detected from the Coral Sea material -- P. pseudogranulosus. Perotrochus pseudogranulosus is rather similar to P. caledonicus but can be distinguished by a more conical shell with much more flattened basal disc, the presence of a characteristic strong metallic lustre on the shell surface, and a more regular "checkerboard" pattern under the selenizone. The spiral cords tend to be finely beaded, especially above the selenizone, hence the specific epithet. Phylogenetic reconstructions using the COI gene suggest it is in fact most closely related not to P. caledonicus but to P. deforgesi Métivier, 1990, which is sister to the P. caledonicus -- P. wareni group. The original description was based only from materials collected from the Coral Sea and restricted to the Chesterfield Plateau; but seeing a number of specimens has turned up in the shell trade throughout the past years with the locality data near New Caledonia, its true distribution may extend to as far as western New Caledonia. Presumably a carnivorous grazer feeding mostly off sponges like other pleurotomariids, it inhabits rather deep water around -300~500m deep. Typical shell diameter around 40mm, extremely large specimens may exceed 55mm. This species appears to be rare in the shell trade market, much rarer than either P. caledonicus or P. wareni, most likely due to its main habitat in the Coral Sea is too remote for regular visits to be made.
Neptunea nivea Okutani, 1981<br /> BUCCINIDAE<br /> -1300m, Cape Erimo, Off Shoya, Horoizumi District, Hokkaido, Japan, 2010/x, 104.4mm <br /> <br /> Despite its plain appearance, Neptunea nivea is a cold-water whelk most sought-after by collectors of the family Buccinidae, especially in Japan. This is because it is a bathyal species inhabiting very deep water around -1000~3000m, and as a result it very rarely appears on the market. A carnivorous and scavenging gastropod inhabiting soft muddy bottoms, it is supposedly endemic to a small part of Pacific Japan ranging from Miyagi Prefecture to southern Hokkaido, although its true range may extend to the Sea of Okhotsk. Most specimens have been obtained as trawl by-catches from either off Kinkasan, Miyagi Prefecture or Cape Erimo, Hokkaido. The shell is ornamented by indistinct spiral ridges which is weakest on the body whorl, and bear a thin layer of greenish brown periostracum which is usually almost completely eroded away in adult specimens. The apex is usually corroded to a certain extent; the operculum is smaller than the aperture although a certain variation is seen in its size relative to the aperture. Typical shell length around 100mm, extremely large specimens may exceed 140mm. It may be confused with Neptunea convexa Goryachev, 1978, but differs from it by having a more inflated shell, deeper suture, and relatively shorter spire. It has been placed by some authors, such as Higuchi, 2006, in the genus Tacita; but it is currently generally accepted to be a member of Neptunea.
Buccinum lamelliferum Lus, 1976 sensu Higuchi, 2006<br /> BUCCINIDAE<br /> -1300m, Trawled, Off Kinkazan, Miyagi Prefecture, Japan, 2006/vi, 99.0mm <br /> <br /> The true identity of this dignified, graceful, and spectacularly sculptured whelk has been much debated. This shell is characterised by three very strong, erected spiral keels (the third is below the suture line and may be very weak) and inhabit soft bottoms of great bathyal depths between -1000~3000m. It is an extremely rare shell especially in collectible condition, partly due to the great depths it dwells in; it is much sought-after among Japanese collectors. Vast majority of specimens have been collected off Miyagi Prefecture, Japan. The Japanese collector Shigeo Higuchi beautifully showed six specimens in his major publication "Northern Shells" (2006, Plate 107-108, "Higuchi shells" hereafter) and referred them to the name Buccinum lamelliferum Lus, 1976 after the specimen illustrated (Fig. 209, p. 498) in Prof. Takashi Okutani's "Marine Mollusks in Japan" (2001). There is a very similar species, Buccinum kashimanum Okutani, 1964, which is known to show vast variation between having no spiral keels and having as many as five spiral keels; but Higuchi deemed his specimens differed from B. kashimanum by the lack of conspicuous spiral threads which characterises B. kashimanum. This was true for Higuchi's specimens which only had very fine and discreet striations (as illustrated here). Interestingly however, the specimen in the Okutani book that Higuchi compared with actually has noticeable spiral threads like B. kashimanum and is thus probably actually a variation of that species. Furthermore, it was realised that the holotype of B. kashimanum has a similar sculpture with two storng keels and only very weak spiral striations. A comparison with the holotype of B. lamelliferum also reveals that the holotype actually has four spiral keels and appear quite different from the Higuchi shells (although some of the B. lamelliferum paratypes did have three keels their positions differed). Whether the true B. lamelliferum is actually also a synonym of B. kashimanum is an interesting question but fresh specimens from the type locality (off Kuril Islands) is required to shed further lights on this matter. The distribution range of the true B. lamelliferum is probably only north of Hokkaido, Japan to Kuril Islands; whereas the range of B. kashimanum is from Kashima-nada, Ibaragi Prefecture to Hokkaido, Japan. It therefore appears that the Higuchi shells is most likely not B. lamelliferum but either an extreme variation of B. kashimanum or an undescribed species; recent publications such as Hasegawa, 2009 and Higuchi, 2014 have adopted the former explanation and refer to the Higuchi shells as B. kashimanum VAR. Nevertheless, in the shell trade market (especially locally in Japan), the name B. lamelliferum still refer to this form (i.e., the Higuchi shell) and this is unlikely to change for sometime as this form is much rarer and fetch much higher prices than standard B. kashimanum (which is only somewhat uncommon in good condition). Typical shell length around 90mm, extremely large specimens may exceed 110mm.
Leptoconus kawamurai (Habe, 1962) <br /> CONIDAE<br /> Naze, Amami Ōshima, Kagoshima Prefecture, Japan, 1989/vii, 51.4mm <br /> <br /> The "Kawamura's Cone" is an elegant Western Pacific conid with a relatively tall spire and tent-like pattern. Although it is widely accepted to distribute in the Ryukyu Islands from the Amami Islands (type locality) to southern Okinawa, morphologically similar specimens have been taken from Taiwan and even as far as Guam. Vast majority of specimens are dead-collected from sands pumped up from a few dozen metres deep for making beaches and harbour works in Okinawa, such specimens are uncommon. Live specimens are extremely rare and it was once even believed to be an extinct species, but the first live specimen was obtained in 1989 from Naze, Amami Ōshima Island, followed by a few more. A carnivorous and predatory gastropod probably feeding mostly on other molluscs, it inhabits rather shallow waters up to 50m deep. It is a There is a long debate about whether it is a geographic subspecies/form of Leptoconus milneedwardsi (Jousseaume, 1894) or a separate species, although in the recent years it is generally treated as a full species in its own right. It differs from L. milneedwardsi by the consistently much smaller size (up to 100 mm vs up to 180 mm in shell length) and a much shorter spire. Typical shell length around 70mm, extrmely large specimens may exceed 90mm.
Cymbiola perplicata (Hedley, 1902) <br /> VOLUTIDAE<br /> Lihou Reef, Coral Sea, Off Queensland, Australia, 1995/xii, 73.0mm <br /> <br /> The "Entangled Volute" is a delightful volute characterised by stunning golden axial lines, and is a much sought-after rarity among the volutes. The original description was based on three poor beached shells from Australian fishermen, but with no further specimens being found its true provenance remained a mystery. That is, until its re-discovery in the late 1970s by Mr. Tom Nielson of Yeppoon, Queensland, Australia and his team. Nielson had already re-discovered other rare shells, including another rare volute Cymbiola thatcheri (McCoy, 1868), using special shell dredges in the early 1970s on-board the chartered boat "Coralita". His early searches for C. perplicata funded by Mr. John du Pont had ended in no avail, however; and it was only after repeated cruises (also on-board the "Coralita") that he finally managed to locate and collect live specimens of C. perplicata in the Coral Sea. His early expeditions were recorded in a film entitled "In Search of the Perplicata", though virtually no remaining copies of it appear to exist. Today it is known to be an endemic of the Australian Coral Sea, and remains rather scarce still. A carnivorous gastropod like all volutes, it inhabits sandy bottoms of shallow to moderate depths around -2~40m. Typical shell length around 65mm, extremely large specimens may exceed 90mm.
Morum dennisoni (Reeve, 1842) <br /> HARPIDAE<br /> -200~250m, Trawled, Cuba, 2000/x, 52.0mm <br /> <br /> A truly magnificent orange-red parietal shield ornamented with white pustulation makes "Dennison's Morum" one of the most beautiful Moruminae species. A classic Carribean rarity first described from John Dennison's cabinet, it was selected as one of S. Peter Dance's 50 "Rare Shells" (1969) and was virtually unobtainable until the late 20th century. Somewhat variable in size, colouration, extent of shield pustulation, and strength of shoulder spines. The general form varies also according to size, with larger specimens becoming more elongated with weaker shoulder spines. A carnivorous and scavenging gastropod inhabiting sandy to muddy bottoms, it is usually found in rather deep water around -50~200m deep. Its geographic range is quite wide, from North Carolina, USA to as far south as Brazil. Most specimens are caught as by-catches of shrimp trawlers. Today it is still somewhat rare, and due to the high demand large specimens in good condition continue to fetch considerable prices. Typical shell length around 45mm, extremely large specimens may exceed 65mm.
Hysteroconcha lupanaria (Lesson, 1831)<br /> VENERIDAE<br /> Guaymas, Mexico, 1968/x, 78.2mm<br /> <br /> The "Panamic Comb Venus" is an immediate standout among bivalves with two rows of long spines protruding from the posterior slope of each valve as it is very unusual for a non-spondylid bivalve to have long spines. Younger specimens tends to have longer, more intact spines; large specimens usually have most spines broken off. It is a locally common burrowing filter feeder living on sandy bottoms from intertidal to -5m depth, but due to its limited distribution specimens are uncommon on the shell trade market. Large specimens with good spines, especially, are quite rarely seen. In life it is buried with its long spines positioned upwards, possibly used as a defence against predators. Distributed in the Eastern Pacific Ocean from Mexico to Peru, it is very similar to its congeners H. dione (Linnaeus, 1758) and H. multispinosa (Sowerby II, 1851). Hysteroconcha dione tends to have shorter spines and is distrubuted only in the Western Atlantic Ocean, whereas H. multispinosa is also an Eastern Pacific species but has more prominent, erect ribs and more numerous spines. Typical shell length without spines about 40mm, extremely large specimens may exceed 65mm and length including spines may exceed 90mm. It has long been placed in the genus Pitar, and is still often seen listed under that genus.
Tropidophora deburghiae (Reeve, 1861) <br /> POMATIIDAE<br /> High in tree tops, About 50km into mountainous primary forest accessible only by muddy trail, 40+ km north of Mananara on road to Maroantsetra, Coastal northeast Madagascar, 2000/x, 47.9mm <br /> <br /> A truly eccentric combination of shape and pattern makes "Mrs. de Burgh's Torpid" one of the most outstanding and famous out of many landsnail species endemic to the great island of Madagascar. It is endemic to northeastern Madagascar, living deep in rainforest and high on tree tops, making it a difficult species to collect. An assessment by the IUCN in 1996 concluded that it was an endangered species and although it is still considered rare and endangered today, little further information have become available to provide a reliable update on the current status of its population. The shell form is little-varied although the pattern vary slightly among specimens. It is often seen listed under the family Pomatiasidae, but Pomatiasidae is currently considered to be a junior synonym of Pomatiidae. Although a landsnail, its chalky operculum reveals its systematic position in the superfamily Littorinoidea, meaning it is in fact a close relative of periwinkles which have managed to invade the terrestrial ecosystem. Typical shell diameter around 45mm, very large specimens may exceed 55mm.
Perotrochus vicdani Kosuge, 1980 <br /> PLEUROTOMARIIDAE<br /> -200~250m, Balut Island, Davao Occidental, Mindanao, Philippines, 2008/x, 56.0mm <br /> <br /> The "Victor Dan's Slit Shell" is a vibrant light-weight Western Pacific pleurotomariid ranging from the Philippines to Vietnam, although vast majority of specimens known originate from the Philippines. It was the first extant slit shell species to be discovered in the Philippines, being described ten years earlier than Mikadotrochus gotoi (Anseeuw, 1990). The form is quite variable in terms of spire height and steppedness, and so is the colouration in terms of strength of redness as well as the amount of flammules. Specimens from the area between Balicasag and Siquijor tends to have more intense red colour than usual. A carnivorous grazer feeding mostly on sponges, it inhabits rather deep water around -100~400m in depth. Typical shell diameter around 50mm, extremely large examples are known to exceed 70mm. Although it used to be a very rare species in the past, thanks to deep-water tangle nets smaller sized specimens are only uncommon nowadays, although large specimens over 55mm in shell diameter remains scarce. It is named in honour of Mr. Victor Dan, a famous shell enthusiast, collector, and dealer based in the Philippines.
Bayerotrochus africanus (Tomlin, 1948) <br /> PLEUROTOMARIIDAE<br /> -300m, Trawled, Off Durban, Natal, South Africa, 1986/x, 116.7mm <br /> <br /> The "African Slit Shell" is a large, light weight pleurotomariid native to eastern and southern Africa, ranging from around Mozambique to South Africa. Most specimens originate as trawl by-catch off South Africa, and it appears to be an uncommon species. It is quite variable in colouration of the flammules, ranging from pale to deep red. A carnivorous grazer feeding mostly on sponges like other slit shells, it inhabits sandy to muddy bottoms of rather deep water around -150~400m in depth. It is quite similar to its common congener B. teramachii (Kuroda, 1955) found in the western Pacific, but has a more strongly stepped spire and its spiral striations are much less beaded compared to B. teramachii. The shell therefore typically appear broader and smoother with higher gloss than B. teramachii. Although B. teramachii has been considered to be its subspecies in the past, both are currently recognised as separate species in their own right. Typical shell diameter around 110mm, though very large specimens may exceed 130mm.
Bayerotrochus teramachii (Kuroda, 1955) <br /> PLEUROTOMARIIDAE<br /> -200~250m, Trawled, Off Makurazaki, Kagoshima Prefecture, Japan, 2010/vi, 90.6mm <br /> <br /> The "Teramachi's Slit Shell" is a brilliantly lustrous pleurotomariid ranging from Honshu, Japan to Taiwan to South China Sea. It is characterised by the golden surface with a metallic sheen, as well as numerous fine but strongly and regularly beaded spiral lirae. The delicately beaded sculpture is more or less consistent among specimens. The shell form, on the contrary, is quite variable especially the spire profile. It was previously considered a Western Pacific subspecies of Bayerotrochus africanus (Tomlin, 1948) but today it is widely accepted as a full species in its own right. Indeed, it is rather similar to many Indo-Pacific Bayerotrochus species including B. africanus but also others such as B. westralis (Whitehead, 1987) and B. philpoppei Anseeuw, Poppe & Goto, 2006; these may form a species complex but genetic data required for further insights is currently lacking. Once a rare species and commanded high prices but since deep-water trawlers in Japan and Taiwan started bringing large quantities to surface its price has plummeted, even more so after the Chinese trawlers started doing the same. It is now the second most common pleurotomariid on the shell trade market, after Mikadotrochus hirasei (Pilsbry, 1903). A carnivorous grazer feeding mostly on sponges, it inhabits sandy bottoms of rather deep water around -200~600m. Typical shell diameter around 100mm, extremely large specimens may exceed 140mm. Its name honours the late Mr. Akibumi Teramachi, who is widely accepted as the greatest Japanese collector of the time. Teramachi was a painter who lived in Kyoto, and after he passed away his collection was bequeathed to Toba Aquarium on the condition of permanent storage. This included the holotype specimen of B. teramachi, which still resides in the Toba Aquarium Collection today. Since then Toba Aquarium has become famous for its affliation with shell collecting and continues to have a shell dealer department today.
Lyncina kuroharai (Kuroda & Habe, 1961) <br /> CYPRAEIDAE<br /> -150m, Trawled, Okinoshima, Munakata, Fukuoka Prefecture, Japan, 1980/vii, 40.1mm <br /> <br /> The "Kurohara's Cowrie" is a lovely medium-sized cypraeid ranging from Honshu, Japan to East China Sea to Taiwan. A classic rarity among Western Pacific cowries, it can be safely separated from other superficially similar Lyncina species such as L. schilderorum Iredale, 1939 and L. sulcidentata (Gray, 1824) by its very fine teeth, curved aperture, and inflated shape. It is a omnivorous grazer living among sponges and rubbles, usually in relatively deep water around -50~250m, although it is occasionally found as shallow as -10m. Very rarely such specimens are washed up on the beach, becoming a rare trophy of beachcombers. Though in recent years Chinese trawlers have brought up numerous specimens from the East China Sea making it much easier to acquire, it is very prone to imperfections such as growth scars and octopus holes and perfect specimens are still very scarce today. Typical shell length around 40mm, extremely large specimens are known to exceed 60mm. It is named in honour of Kazuo Kurohara of Japan.
Mikadotrochus beyrichii (Hilgendorf, 1877) <br /> PLEUROTOMARIIDAE<br /> -100~120m, Trawled, Off Mimase, Kōchi, Kōchi Prefecture, Japan, 1969/vi, 84.4mm <br /> <br /> The "Beyrich's Slit Shell" is a striking pleurotomariid endemic to Japanese waters, best known from the central portion of Honshu Island. Although the third to be formally described it is actually the earliest living slit shell recorded and illustrated in the recent literature, being included in Japanese books such as "Kigai-zufu" (Kenkado Kimura, 1775) and "Mokuhachi-fu" (Sekiju Musashi, 1843) long before Perotrochus quoyanus (Fischer & Bernardi, 1856) was discovered in the Caribbean Sea. These Japanese books were unknown to scientists outside the country then, however. This species was thus overlooked until Franz Martin Hilgendorf (1839-1904), a German zoologist, found a specimen in a souvenir shop of Enoshima, Kanagawa Prefecture, Japan in 1876. He described it the following year, naming it after Heinrich Ernst Beyrich (1815-1896), a famous German palaeontologist who first proposed the term 'Oligocene'. It has traditionally been a greatly celebrated rarity, especially among Japanese collectors, and remains scarce nowadays. After Hilgendorf reported its existence the British Museum (Natural History) in London commissioned the University of Tokyo to find a specimen. It was the eminent professional marine animal gatherer Kumakichi Aoki (1864-1940), working for the Misaki Marine Station, who successfully collected a living specimen in the following spring. He was rewarded with the prize of 40 Japanese yen, a huge sum back then. Upon receiving the prize Aoki supposedly exclaimed "I've become a millionaire!", which leads to this species being sometimes called "Cho-ja-gai" (Millionaire Shell) in Japan, even today. A carnivorous grazer feeding on sponges, it usualy inhabits rocky bottoms around 100~300m deep but has been found as shallow was -30m, making it the shallowest living of all recent pleurotomariids. Strong, broad radial lirae on the shell surface are crossed by relatively infrequent axial ribs to generate the characteristic coarsely chequered sculpture. The frequency and extent of red flammules vary according to localities, with specimens from Chiba Prefecture and Tokyo Bay having the darkest colouration. The shell form also vary somewhat by locality, for example shells from Kōchi Prefecture (shown) are usually broader than typical specimens from Chiba Prefecture. Typical shell length around 70mm, very large specimens may exceed 100mm.
Perotrochus atlanticus Rios & Matthews, 1968 <br /> PLEUROTOMARIIDAE<br /> -200~250m, Trawled, Off Cabo de São Tomé, Rio de Janeiro, Brazil, 1998/x, 62.5mm <br /> <br /> The "Atlantic Slit Shell" is a gorgeous medium-sized pleurotomatiid endemic to southern Brazil, from around Rio de Janeiro to as far south as the Brazil-Uruguay border. The shell is heavily ornamented by finely beaded coarse spiral cords and numerous flammules, the colouration of which vary from red to brown and the saturation vary from one specimen to another. The characteristic shape of adult shells is formed by the gradual shifr of the whorls being smooth-sided, as in the early teleoconch, to strongly inflated and bulging ones in the later stages. It is locally only uncommon and is perhaps the most easily obtainable Atlantic slit shell, although it is very susceptible to erosion and bore-holes, specimens in fine conditon are thus still considerably rare. A carnivorous grazer feeding on sponges, it inhabits sandy to muddy bottoms of rather deep water around -150~300m. Typical shell diameter around 65mm, extremely large specimens are known to exceed 85mm. The spire is variable in height although usually it is usually low; the name Perotrochus notialis (Leme & Penna, 1969) refers to a high-spired form and is now considered to be a junior synonym.
Halicardia nipponensis Okutani, 1957 <br /> VERTICORDIIDAE<br /> -500~600m, Trawled, Off Sōma, Hamadōri, Fukushima Prefecture, Japan, 2006/viii, 32.0mm <br /> <br /> The exceptionally exquisite Halicardia nipponensis, with its unique shape formed by two strong radial ridges, is certainly one of the most unusual bivalves of all. It is a carnivorous bivalve inhabiting muddy bottoms of deep-water ranging from -500~1500m, and feeds on small invertebrates such as copepods by capturing them using mucus-lined tentacles. It is a renowned endemic of Japan only found off the northern half of the Pacific Honshu. An incredibly coveted species, especially in Japan where its beauty is greatly celebrated, it is only very rarely obtained by deep-water trawling and command high prices. When seen from the anterior view its shape resembles two hearts, the interior also carry heart-shaped hinge tooth. Futhermore, its side views are strongly reminiscent of the kanji (Chinese character) for "heart". It is therefore known in Japan as the "Nippon-otohime-gokoro" (literally, "Heart of the Japanese Maiden Princess"), aptly named by Prof. Takashi Okutani. This brilliant wamei (Japanese name) is part of the reason why it is an especially popular shell in Japan. Although its congener Halicardia maoria Dell, 1978 from New Zealand is tentatively reported to be associated with deep-sea hydrocarbon seeps, it is unclear whether H. nipponensis does the same. Typical shell length around 32mm, extremely large specimens are known to exceed 40mm.
Perotrochus quoyanus (Fischer & Bernardi, 1856) <br /> PLEUROTOMARIIDAE<br /> -200~210m, Collected by submersible, Off Sandy Lane Bay, Barbados, 1998/vi, 52.4mm<br /> <br /> First discovered by Commandant Beau in the Marie-Galante Island, Guadeloupe in 1855, the legendary "Quoy's Slit Shell" was the first living pleurotomariid species formally exposed to science. The encounter of this species is among one of the most important landmarks in malacology and generated great excitement, as previously this important ancestral lineage of basal gastropods were considered long extinct; the finding of living species opened up wholly new possibilities in studying the evolution of gastropods. It was therefore selected as one of S. Peter Dance's 50 "Rare Shells" (1969). The first specimen (i.e., the holotype) was taken from a fisherman's pot set in deep-water, and it was inhabited by a hermit crab. This was closely followed by the exposure of Entemnotrochus adansonianus (Crosse & Fischer, 1861) and Mikadotrochus beyrichii (Hilgendorf, 1877), up until now some 30 living pleurotomariid species have been described. In fact, M. beyrichii was illustrated in the Japanese books such as "Kigai-zufu" (Kenkado Kimura, 1775) and "Mokuhachi-fu" (Sekiju Musashi, 1843) long before the detection of P. quoyanus, but these books was not known to scientists in the western world then. Today, P. quoyanus is known to have a rather wide distribution around the Caribbean Sea from Yucatan, Mexico to Virgin Islands to Venezuela. Furthermore there is one recognised subspecies, P. quoyanus insularis Okutani & Goto, 1985, described from the Bermuda Islands and has a much taller spire with more swollen whorls. Specimens with a similar form has since been found as far as Honduras, however. The name Perotrochus gemma Bayer, 1965 was previously considered to be a separate species but is now regarded as a gemmate form of P. quoyanus and thus a junior synonym of it. The shell is therefore rather variable in spire height and strength of surface sculpture (i.e., 'gemmation'), the colouration is also variable from rather pale to strongly flamed with reddish axial bands. It is a carnivorous grazer feeding mostly on sponges and usually inhabit hard substrates in deep water around -180~350m. Due to its deep habitat it is still a rare shell, especially live-collected in fine conditon; such shells are virtually only obtainable using deep-water submersibles as trawls rarely operate near the rocky walls it inhabit. Typical shell length around 45mm, extremely large specimens may exceed 60mm.
Mikadotrochus salmianus (Rolle, 1899) <br /> PLEUROTOMARIIDAE<br /> -240m, Trawled, Off Tosa, Kōchi Prefecture, Japan, 1967/vi, Ex-Coll. Helen Boswell, 116.2mm <br /> <br /> The "Salmiana Slit Shell" is an elegant pleurotomariid with a blazing coluration and a characteristically tall spire, ranging from Honshu, Japan to Taiwan to Philippines. A much sought-after rarity, most specimens have generally come from Taiwan although recently Chinese fishermen have also trawled many (mostly poor) specimens from the East China Sea. It reaches the largest size in Tosa Bay, Japan where the shells are the thickest and with a rather pale colouration; the shells gradually thins down towards south with specimens from the Philippines being the lightest in build but with a dark colouration. Both Tosa Bay and Philippines specimens are still very scarce today, especially in large size, though in the East China Sea it is probably best described as uncommon. A carnivorous grazer feeding on sponges, it inhabits hard substrates of rather deep water around -100~400m. Typical shell length around 90mm, extremely large specimens are known to exceed 135mm. For many decades since its description it was confused with its congener Mikadotrochus beyrichii (Hilgendorf, 1877) due to the small quantity and poor quality of available specimens. As better specimens surfaced, however, its obvious differences with M. beyrichii quicky became apparent and it has become widely accepted as a valid species since the 1970s. A well-known synonym is Mikadotrochus schmalzi Shikama, 1961.
Entemnotrochus adansonianus (Crosse & Fischer, 1861) <br /> PLEUROTOMARIIDAE<br /> -120~130m, Collected by submersible, Off Half Moon Bay, West End, Roatán Island, Bay Islands, Honduras, 2009/ix, 129.3mm <br /> <br /> The majestic and magnificently flamed "Adanson's Slit Shell" is perhaps one of the most beautiful pleurotomariids, and also a renowned and celebrated classic rarity among them. As the first of S. Peter Dance's 50 "Rare Shells" (1969) a photo of one of the oldest surviving specimens, purchased by Samuel Archer in Barbados in the 1800s, serves as the book's cover. A rather widely ranging species in the western Atlantic Ocean, it is best known from the West Indies and Caribbean Sea but the full geographical distribution ranges from as far as Bermuda down to Brazil. Specimens from Bermuda differs from all others in having a more vertically compressed shell of much smaller size (to 100mm), the spire also appears much more strongly stepped as the whorls are strongly shouldered. These Bermudian specimens are thus separated as a valid subspecies, E. adansonianus bermudensis Okutani & Goto, 1983. It is a carnivorous grazer feeding on sponges like the majority of pleurotomariids, and inhabits vertical rocky walls of rather deep water around 100~300m in depth. Even with all these knowledge about its ecology it is still a very rare shell on the international market nowadays because the steep rock walls it inhabit is well protected from traditional fishing methods. Dredging or trawling only uncover dead-taken or crabbed specimens, and traps have been effective in gathering only crabbed shells. Most live-taken specimens in fine quality, like the one shown, have therefore been carefully collected by underwater submersibles. The subspecies E. a. bermudensis is rarer still, with virtually no live taken examples so far known. The pattern is somewhat variable, although most specimens carry alternating red and pale patches. Large specimens tends to have less sharp, saturated colouration. Typical shell diameter around 110mm, although extremely large examples are known to reach a staggering size of 190mm. It is the second largest of all living slit shells, only surpassed by its Pacific congener E. rumphii (Schepman, 1879). Currently these two species are the only recognised valid species of the genus Entemnotrochus.
Kendrickiana veitchi (Smith, 1971) <br /> PENICILLIDAE<br /> Low tide, Broome, Kimberley, Western Australia, Australia, 203.1mm <br /> <br /> The "Veitch's Wateringpot" is a strange and wonderful penicillid endemic to Western Australia and Southern Australia, Australia; best known from the Great Australian Bight. It is a member of the bivalve superfamily Clavagelloidea, characterised by their remarkable behaviour of switching from growing the true shell to building a calcareous tube, called the adventitious tube. At the earliest stages of life after settlement it bears a normal bivalved shell, which is still attached to the outside of the adventitious tube and visible; although in this species it is largely incorporated into the tube. Uniquely among penicillids its adventitious tube is strongly bulbous at the "watering-pot" end, divided into hundreds of small tubes, and is not distinctively fringed like most other species. A filter-feeding species, it appears to be restricted to soft bottoms of seagrass beds (such as Posidonia sp.) and inhabit subtidal waters down to about 50m deep. In life it lives vertically buried with the "watering-pot" end down. Although probably only uncommon locally, it is rarely seen in the international shell trade market. Previously it has been placed in the genus Brechites and then Foegia, but after detailed anatomical investigation a new genus, Kendrickiana, was erected to house it; it is currently the only species placed in that genus. Typical length of the adventitious tube around 200mm, although very large specimens are known to exceed even 370mm.
Paramoria guntheri (Smith, 1886) <br /> VOLUTIDAE<br /> -21m (-70 ft), In sandy rubble, By diver, Thorny Passage, South Australia, Australia, 54.5mm <br /> <br /> The deliciously patterned "Gunther's Volute" is a celebrated classic rarity among the volutes, endemic to southern Australia. Initially only known from a handful of dead-collected specimens, a live specimen was first discovered in May 1973 off Port Lincoln, South Australia. Photographs of this specimen was published, revealing to the world the equally beautiful animal, covered in a web-like pattern of similar colouration as the shell. A carnivorous and predatory gastropod, it inhabits sandy to muddy bottoms of shallow to moderate depths around -10~50m. Today it is still considerably rare and highly sought-after by collectors. The attractive pattern is rather variable and the axial lines vary considerably in frequency among specimens. The two spiral bands may be solid or dotted when present, but they may also be completely absent. The form without spiral bands is rarer and was originally described as a separate species Voluta adcocki Tate, 1889; now considered a synonym but is still widely used as a form name in shell trade. Furthermore, the shoulder nodes are also rather variable in strength. Typical shell length around 45mm, extremely large specimens may exceed 65mm.
Netastoma darwinii (Sowerby II, 1849) <br /> PHOLADIDAE<br /> Inside sand rocks, San Jorge Gulf, Caleta Olvia, Santa Cruz, Argentina, 2004/i, Coll. Andres R. Bonard, 39.2mm <br /> <br /> The "Darwin's Piddock" is a spectacular South American pholadid with a very peculiar shape, ranging from southern Brazil to Argentina. A rock-burrowing bivalve, it repeatedly rotates its shells using a set of specially adapted muscles to mechanically grind a tubular burrow in soft rocks, which it then reside within for the rest of its life. It is a filter-feeder inhabiting very shallow to shallow waters down to about 15m deep, during feeding it extends its siphons out of the burrow but rest of the body remains protected by the rock. A rather rare species, perhaps owing to the fact that it is difficult to locate, and even more difficult to extract intact from its rocky burrow. Typical shell length around 30mm, very large specimens may exceed 40mm. The genus Nettastomella was erected by Carpenter in 1865 to house this eccentric species, but it is now deemed to be an unnecessary replacement name for genus Netastoma, its current genus.
Gigantopelta aegis Chen, Linse, Roterman, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2785m, 'Tiamat Chimney', 37°47.03'′S, 49°38.97'E, Longqi hydrothermal vent field, Southwest Indian Ridge, ROV Kiel 6000 Dive 142 on-board RRS James Cook expedition JC67, 2011/xi/29, 40.2mm <br /> <br /> The "Aegis Shield" is a large hydrothermal vent endemic peltospirid known only from the Longqi (aka Dragon) hydrothermal vent field, Southwest Indian Ridge, Indian Ocean; which is a bathyal site around -2700~2800m in depth. It houses chemosynthetic endosymbiont bacteria in a much enlarged oesophageal gland, and appear to rely on these for nutrition. Interestingly both its shell and operculum are covered in a thick layer of iron oxide (i.e., rust), on the operculum especially this layer is a circular slab that can reach a thickness of 5mm. It is thus another "iron-armoured snail" like the 'scaly-foot gastropod' Chrysomallon squamiferum Chen et al., 2015. Most intriguingly however the 'scaly-foot', which it lives side-by-side with, has iron sulfide coating instead of iron oxide; it is not known why the two large peltospirids living in the same environment use different iron compunds to coat their exterior surface. Furthermore, its congener G. chessoia Chen et al., 2015 from Antarctic vents does not have such iron coating at all. The function (if any) of this coating is yet unclear, although microbial activity likely contribute to its formation. The specific epithet "aegis" refers to the renowned powerful mythical shield of Athena and Zeus from the Greek mythology; named for its great thickness and also the well-polished appearance which fits well with the description of the legendary shield which is sometimes described as "mirror-like". The bluish-white shell is quite thin, covered by a rather thick periostracum which is in turn covered by the thick rust layer. With an average shell length of 35mm and very large specimens reaching 44mm, it is a gigantic peltospirid only exceeded in size by C. squamiferum and G. chessoia. Although a common species in its habitat, due to the extreme difficulty in collecting specimens from hydrothermal vents, it is unfortunately a virtually unobtainable species for personal collection.
Gigantopelta chessoia Chen, Linse, Roterman, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2646m, ‘Cindy's Castle’ hydrothermal vent site, 56°05.31′S, 30°19.10′W, E2 segment, East Scotia Ridge, By ROV Isis Dive 189 on-board RSS James Cook cruise JC80, 2012/xii/12, 45.9mm <br /> <br /> The "ChEsSO's Shield" is a large hydrothermal vent endemic peltospirid known only from the Antarctic deep-sea hydrothermal vents in E2 and E9 segments of the East Scotia Ridge, off South Sandwich Islands. The vent sites it inhabits are bathyal, around -2400~2600m in depth range. It houses chemosynthetic endosymbiont bacteria in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With an average shell length of around 35mm and very large specimens exceeding 45mm, it is not only the largest peltospirid but also the largest member of the clade Neomphalina. Its size record is closely followed by the 'scaly-foot gastropod' Chrysomallon squamiferum Chen et al., 2015 (reaching 45.0mm) and its congener Gigantopelta aegis Chen et al., 2015 (reaching 44.2mm). The shell is rather thin but rigid, and covered by a thick olive to brown periostracum of a similar thickness. The operculum is unusually large for the family, most of which have reduced operculum or completely lost it, and covers the entire aperture. The genus name "Gigantopelta" is taken from "Giganto-", which means "giant" but is also an reference to the legendary Giants of the Greek mythology; and "pelta" meaning "shield", referring to the large operculum as well as the family name Peltospiridae. The specific epithet "chessoia" is taken from the ChEsSO (Chemosynthetic Ecosystems of the Southern Ocean) project, primarily funded by the Natural Environment Research Council, United Kingdom, which in 2010 first discovered and surveyed the Antarctic vents it inhabits. ChEsSO was part of the ChEss (Biogeography of Deep-Water Chemosynthetic Ecosystems) project in the Census of Marine Life initiative. Although a dominant species in its habitat, due to the extreme difficulty in collecting specimens from hydrothermal vents it is unfortunately a virtually unobtainable species for personal collection.
Samarangia quadrangularis (Adams & Reeve, 1850) <br /> VENERIDAE<br /> Dived, Zanpa-Misaki, Yomitan, Okinawa Island, Okinawa Prefecture, Japan, 2006/vi, 59.3mm <br /> <br /> The "Samarangia Clam" is a highly unusual venus clam with a peculiar habit of cementing sand grains over its shells to form 'pseudo-shells' that completely conceal the true shells, termed aranaceous coating. The sand grains are first held together by a mucus layer, and later become permanently concreted by aragonitic calcium carbonate. The function of this rather thick coating has been argued to be protective and camouflage, although no direct evidence has been presented. Surface of the arenaceous coating is ornamented with a number of prominent radial ribs, the strongest few being clearly nodulous. The underlying true shell is actually completely smooth and overlaid by a thin periostracum, the only way to see it is by removing the coating through intensive polishing. Its distribution range is quite wide in the Western Pacific from the Coral Sea to Honshu, Japan to Indonesia. Previously its range was thought to extend as far as Mauritius and Reunion, but recent studies have separated the Indian Ocean and Red Sea population as a distinct species -- Samarangia lewinsohni Mienis, 2011. A filter-feeding bivalve inhabiting sandy bottoms of rather shallow waters around -10~50m, it is not uncommon throughout its range. Typical shell length around 70mm, very large specimens may exceed 100mm.
Neancistrolepis glabra Habe & Ito, 1973 <br /> BUCCINIDAE<br /> -730~740m, 44°12'E 144°29'E, Trawled, Off Abashiri, Hokkaido, Japan, 2006/vii, 57.2mm <br /> <br /> Neancistrolepis glabra is a cold-water whelk with smooth, glossy periostracum ranging from Hokkaido, Japan to the Okhotsk Sea. A carnivorous and often scavenging gastropod, it inhabits sandy to muddy bottoms of quite deep water around -600~800m. It is a very rarely seen species on the international shell trade, even locally in Japan it is considered a rare species. In fully adult specimens, the outer lip thickens slightly and characteristically flares out, extending anteriorly. The periostracum is darker coloured in adults than juveniles and peels off rather easily when dried. The operculum is teardrop shaped and as usual for the genus Neancistrolepis it is much smaller than the aperture, though not as small as in the genus Parancistrolepis. Typical shell length around 100mm, very large specimens may exceed 140mm.
Spondylus crassisquama Lamarck, 1819<br /> SPONDYLIDAE<br /> -35~40m, Panama Bay, Panama, 2005/viii, 143.8mm <br /> <br /> Much better known by the name Spondylus princeps Broderip, 1833 which was recently synonymised with the current name, the showy "Pacific Thorny Oyster" gains its vernacular name from its distribution range in the Pacific Americas, from Baja California to Peru. Being rather variable in spine development and colouration it has a couple further synonyms including S. basilicus Reeve, 1856 which refers to an orange form, and S. dubius Broderip, 1833. Spondylus leucacanthus Broderip, 1833 with more sparce spines which are usually white was traditionally considered to be a form of this species but currently separated out as a valid species on its own right. A filter-feeding sessile bivalve like all spondylids, it lives attached to hard substrates around moderate depths of -10~50m. Typical shell length including spines around 100mm, very large specimens are known to exceed 170mm. Although a locally common species, specimens of fine quality are uncommon on the international shell trade market.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2785m, Longqi vent field, 37°47.03'S 49°38.97'E, Southwest Indian Ridge, Indian Ocean, 43.1mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2607m, Solitaire vent field, 19°33.41'S 65°50.89'E, Central Indian Ridge, Indian Ocean, Mauritius, 35.2mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 <br /> PELTOSPIRIDAE<br /> -2422m, Kairei vent field, 25°19.218S, 70°02.424E, Central Indian Ridge, Indian Ocean, 39.1mm <br /> <br /> The 'scaly-foot gastropod' is an iconic vent endemic gastropod known only from the Indian Ocean deep-sea hydrothermal vents. The foot, uniquely among gastropods, carry numerous corneous dermal sclerites often mineralised with iron sulfide along with the shell surface, making it the only extant metazoan known to use iron in the skeleton. First discovered at Kairei vent field, Central Indian Ridge (CIR), it has subsequently also been found in Solitaire field, CIR (off Mauritius) and Longqi field, Southwest Indian Ridge (SWIR). The Solitaire population has white sclerites instead of black due to lack of iron in them, most likely due to differences in the vent fluid composition. The function of sclerites has been speculated to be protective or detoxification (by accumulation of sulfide waste), but their true function is yet unknown. It is a holobiont hosting thioautotrophic (i.e., sulfur-oxidising) chemosynthetic endosymbionts in a much enlarged oesophageal gland, and appear to rely on these for nutrition. With shell length that averages at around 35mm and exceeds 45mm in large individuals, it is a very large peltospirid compared to most others which are below 15mm in shell length. Although discovered as early as 2001, a publication containing a formal description and name was not published until 2015.
Cymbiola perplicata (Hedley, 1902) <br /> VOLUTIDAE<br /> -30m, Dived on reef, Lihou Reef, Coral Sea, Australia, 60.0mm <br /> <br /> The "Entangled Volute" is a delightful volute characterised by stunning golden axial lines, and is a much sought-after rarity among the volutes. The original description was based on three poor beached shells from Australian fishermen, but with no further specimens being found its true provenance remained a mystery. That is, until its re-discovery in the late 1970s by Mr. Tom Nielson of Yeppoon, Queensland, Australia and his team. Nielson had already re-discovered other rare shells, including another rare volute Cymbiola thatcheri (McCoy, 1868), using special shell dredges in the early 1970s on-board the chartered boat "Coralita". His early searches for C. perplicata funded by Mr. John du Pont had ended in no avail, however; and it was only after repeated cruises (also on-board the "Coralita") that he finally managed to locate and collect live specimens of C. perplicata in the Coral Sea. His early expeditions were supposedly recorded in a film entitled "In Search of the Perplicata", though virtually no remaining copies of it appear to exist. Today it is known to be an endemic of the Australian Coral Sea, and remains rather scarce still. A carnivorous gastropod like all volutes, it inhabits sandy bottoms of shallow to moderate depths around -2~40m. Typical shell length around 65mm, extremely large specimens may reach 85mm.
Cyrtopleura costata (Linnaeus, 1758) <br /> PHOLADIDAE<br /> Dug out from intertidal mud, Low tide, Cedar Key, Florida, USA, Collected by Edward Nieburger, 1976/v/1, 172.4mm <br /> <br /> This delicate bivalve of otherworldly beauty is aptly named the "Angel Wing", and has attracted the adoration and fascination of shell collectors for hundreds of years. Each thin and almost translucent wing-like valves carry 24-27 strong radial ribs which carry numerous beads that convincingly look like feathers on the wing. It has a rather wide distribution range from Massachusetts, USA to as far south as Brazil, although vast majority of specimens on the market originate from Florida, USA. A large filter-feeding pholadid inhabiting muddy bottoms of very shallow water down to about -5m in depth, it is most common in intertidal waters just below the low-water mark and usually burrow deep into the mud, up to about a metre. The animal is bulky with a powerful foot as well as a hefty fused siphon which is so large that the two valves cannot be closed and instead permanently gape apart when alive. Each valve carry on the inside a apophysis, spoon-like appendage which is a point of attachment for the foot musculature. As usual for the genus Cyrtopleura it has a small butterfly-like mesoplax and also a large, entirely corneous protoplax (both shown) but lacks a metaplax. These accessory plates help cover part of the animal which would be exposed otherwise, due to the large gape in its valves, and is a common feature for members of the famly Pholadidae. When alive both valves are covered by a thin, brown periostracum which is often worn near the umbo. Although it is a common species, large specimens with both the mesoplax and especially the protoplax preserved are very difficult to acquire. Separated single valves are commonly washed ashore on beaches and is a beachcomber's favourite. Typical shell length around 130mm, extremely large specimens may reach 200mm. Its meat is edible and in Mexico, Cuba, and Puerto Rico it is harvested commercially for food and supports important fisheries. Aquacultural research has shown that it is a fast growing species and reaches 50-70mm shell lenth within six months of settlement.
Textilia adamsonii (Broderip, 1836) <br /> CONIDAE<br /> -20~30m, Dived, Rurutu Island, Austral Islands, French Polynesia, 1998/i, 41.0mm <br /> <br /> With truly spellbinding patterns the "Rhododendron Cone" is a great classic rarity among the conids and one of the most sought-after by collectors. One of S. Peter Dance's 50 "Rare Shells" (1969), it is still a very difficult shell to obtain today in fine condition. Although it is often beached after typhoons pass, but such specimens are typicall worn with badly damaged lip. A predatory gastropod like all conids, it is a piscivorous species which hunt fishes using venom injected from its harpoon-like radula. It inhabits sandy bottoms of coral reefs and lagoons and may be found from low intertidal waters down to moderate depths around -60m deep. The shell characteristically carry three broad spiral bands with sparse nebulous patterns which alternate with another three narrower spiral bands with small triangular spots. It has a rather wide distribution range in the Pacific Ocean ranging from Coral Sea to French Polynesia, and varies slightly in form, size, as well as pattern depending on the locality. Specimens from the Marquesas Islands, for example, are rather large and instantly recognisable by their exceptionally intense colouration and more cylindrical (rather than conical) form. Its vernacular name comes from a famous synonym, Conus rhododendron Jay, 1839, which is very appropriate but unfortunately must give way to Broderip's earlier name. Typical shell length around 35~40mm depending on the locality, extremely large specimens are known to exceed 55mm.
Angaria sphaerula (Kiener, 1838) <br /> ANGARIIDAE<br /> Panglao Island, Bohol, Philippines, 2010/x, 70.3mm <br /> <br /> With its astonishing ornamentation the "Kiener's Delphinula" is perhaps the most beautiful angariid, and one of the most exquisite of all gastropods. For a long time since its description it remained a very rare shell, even well into the 20th Century; S. Peter Dance chose it as one of his 50 "Rare Shells" (1969), describing it as "undoubtedly scarce and undeniably beautiful" (p.51). Today, however, it has been revealed to be a rather common species native to the tropical Western Pacific, best known from the Philippines where most specimens originate. An extremely variable species in spine formation, its spines can vary greatly in length, recurvedness, and in structure from a simple tube to being extensively webbed. It is also quite variable in colouration, the two common colours being red and green; an individual may change its colour during its life, as in the specimen shown which shifted from red to green. Large specimens of the form with frilly, webbed spines like flower petals are rare because the frills are exceedingly fragile and prone to damage; such specimens, especially when wholly red, are in great demand and command high prices. A grazing gastropod feeding on algae, it inhabits rocky surfaces of rather deep waters around -50~250m, its deep habitat contributed to its apparent rarity prior to the invention of tangle nets in the Philippines. Typical shell length around 60mm including spines, very large specimens may approach 100mm.
Spondylus regius Linnaeus, 1758 <br /> SPONDYLIDAE<br /> -60~80m, By lobster gillnets, Sakai, Minabe-Cho, Wakayama Prefecture, Japan, 1980/iii, 213.5mm <br /> <br /> The "Regal Thorny Oyster" is a glorious spondylid native to the western Pacific, ranging from Japan to Philippines. It is an exceedingly famous species and collector's item due to its large size, long spines, and gorgeous colouration; chosen by S. Peter Dance as one of his 50 "Rare Shells" (1969). Used to be a very rare species until the 20th Century but today it is a common shell, to the extent that it is often seen sold as home decoration. Giant or exceptional specimens, however, are still much prized and fetch high prices. Most specimens are reddish in colour with pale spines but uncommonly wholly orange specimens (as shown) are found, and rarely also yellow ones. Specimens from deep water often have very long spines which may be spatulate and undulating at tips, as well as more fine spines between the main ribs. This form has been given the name Spondylus cumingii Sowerby II, 1847, now considered a synonym of S. regius, and these are also much favoured by collectors. A sessile filter-feeding species living attached to hard substrates, it inhabits shallow to rather deep water ranging between -5~100m in depth. Typical shell length including spines 160mm, extremely large specimens may exceed 220mm. The depicted specimen is a superb deep water orange shell from Japan with all fine spines perfectly preserved.
Nodipecten magnificus (Sowerby I, 1835) <br /> PECTINIDAE<br /> -6~7m, Dived, Fernandina Island, Galápagos Islands, 2000/x, 97.2mm<br /> <br /> The "Magnificent Scallop" is a truly flamboyant pectinid and a famous endemic species of the Galápagos Islands. A much celebrated collector's item, it is a rarity on the shell trade market despite being locally not uncommon because Galápagos Islands is not only difficult to access but also a protected area with strict regulations implemented on collecting. A filter-feeding bivalve, it inhabits shallow sandy bottoms among reefs around -2~50m deep and often attaches itself to hard substrates using byssus threads. The number of ribs is generally between 12 and 13, quite numerous for the genus Nodipecten. Young shells (as shown) usually produce small nodules on the ribs as well as white markings but this stops after a certain size and ribs then become uniform in colouration and lack nodules. The normal colouration is a striking dark red but occasionally orange specimens are found, rarely also brown ones. Typical shell length around 170mm, very large specimens may exceed 220mm.
Beringius miyauchii Habe & Ito, 1972<br /> BUCCINIDAE<br /> -400~450m, Trawled, Off Urup Island, Kuril Islands, 2014/viii, 109.1mm<br /> <br /> The "Miyauchi's Neptune" is a cold-water buccinid with fascinating sculpture native to the Sea of Okhotsk, ranging from northern Hokkaido, Japan to the Kuril Islands. It is a very rare species and is extremely difficult to acquire in fine condition. Many consider it to be a form of Beringius frielei Dall, 1895 but it is clearly distinct from that species with much stronger sculpture, a much more slender shell, and shallower suture. It is also often treated as a subspecies of B. frielei, although this possibility cannot be excluded the geographical distribution of the two species overlap and it is perhaps best to consider them as separate species. A carnivorous and scavenging gastropod, it inhabits soft bottoms of rather deep water ranging between about -100~500m in depth. The apex is always corroded in adult specimens. Typical shell length around 100mm, very large specimens may exceed 130mm.
Austrasiatica hirasei (Roberts, 1913) <br /> CYPRAEIDAE<br /> -100~150m, Balut Island, Davao Occidental, Mindanao, Philippines, 2009/iv, 48.0mm <br /> <br /> The "Hirase's Cowrie" is an exceedingly elegant cypraeid ranging from Kii Peninsula, Japan to Philippines to Queensland, Australia. One of the 'three famed cowries' of Japan along with congener A. langfordi (Kuroda, 1938) and Nesiocypraea teramachii (Kuroda, 1938), it is a much coveted rarity and collector's item. Although in the recent years many specimens have surfaced from the East China Sea and those have been traded with relatively low prices, high quality specimens are still costly. Truly Australian specimens, especially, are extremely scarce. An omnivorous nocturnal gastropod, it inhabits relatively deep water around -100~200m. Typical shell length around 50mm, extremely large specimens may exceed 65mm. It is named in honour of the eminent pioneering Japanese collector Yoichiro Hirase. The first specimen is said to have been discovered from the hands of a young girl in the fishing village of Kii-Tanabe, Wakayama Prefecture, Japan; hence its wamei (Japanese vernacular name) is "Otome-dakara", meaning "Maiden Cowrie".
Otukaia kiheiziebisu (Otuka, 1939) <br /> CALLIOSTOMATIDAE<br /> -800~850m, Trawled, Off Minamisōma, Fukushima Prefecture, Japan, 2013/v, 35.1mm<br /> <br /> Characteristically ornamented with three pleating keels, the "Kiheizi's Top" is an extremely striking calliostomatid and a very famous classic rarity of Japan. It is endemic to Japan with its range restricted to the Pacific side of southern Hokkaido to Honshu to Shikoku. Although its feeding habits are not well known it is most likely a carnivorous grazer feeding on cnidarian and other sessile organisms. Most specimens are collected as trawling by-catch from soft bottoms of deep water around -200~1000 deep, but it is very rare throughout its range and is a highly sought after species. Typical shell length around 30mm, very large specimens as shown may exceed 35mm. It was christened 'kiheiziebisu' after a famous Japanese collector, Mr. Kiheizi Ōshima, who first collected it from the fish market of Chōshi, Chiba Prefecture; 'ebisu' literally means 'top shell' in Japanese. It is also the type species of genus Otukaia, as designated by Ikebe, 1942. Otukaia ikukoae Sakurai, 1994 is a southern form with finely granulated keels instead of smooth ones, it used to be considered as a separate species but is now understood as merely a form and thus treated as a junior synonym.
Zygochlamys delicatula (Hutton, 1873) <br /> PECTINIDAE<br /> -100m, Off Otago Peninsula, South Island, New Zealand, 1993/xii, 62.7mm<br /> <br /> The "Southern Queen Scallop" is a vividly coloured pectinid endemic to New Zealand, mainly distributed on the continental shelf of South Island, in the subantarctic waters southward of Kaikoura, Canterbury. Its size is large for the genus Zygochlamys, with an average shell length around 60mm and very large specimens exceeding 75mm. Due to this relatively large size and the fact that it is a rather abundant species, it is exploited commercially for food and is the only commercially important Zygochlamys species. A filter-feeding species living on soft bottoms, juveniles first settle attached on marine growth such as bryozoans or other mollusc shells. It is most abundant around moderate depths between -150~200m, but may be found across a wider bathymetric range of -70~300m. The colouration may vary from pastel yellow to reddish, and the upper valve is much more intensely coloured compared to the lower valve.
Spondylus echinatus Schreibers, 1793 <br /> SPONDYLIDAE<br /> Cebu Island, Central Visayas, Philippines, 1983/xii/27, 95.1mm<br /> <br /> Spondylus echinatus is a delightfully spined thorny oyster widely ranging across the Indo-West Pacific, south of Amami Islands, Japan. It is a very variable species in terms of spine development and colouration, which has resulted in a number of synonyms being given. A very famous one is Spondylus castus Reeve, 1856 and it is often still referred to as that, since it is listed in many books under that name. The brown shelled and white spined form as shown has been known as Spondylus albibarbatus Reeve, 1856. Both Anton, 1838 and Chenu, 1844 gave it the name Spondylus albus, but both are synonyms. Furthermore, a densely spinous form was given the name Spondylus spectrum Reeve, 1856. The juvenile shell is characteristically white with small black patches. A filter-feeding bivalve which lives a sessile lifestyle with the right valve attached on hard substrates, it is a common species found from low intertidal zone down to about -20m deep. Typical shell length around 90mm, very large specimens may exceed 130mm. Spondylus zonalis Lamarck, 1819 was traditionally considered to be a form of this species, but is now considered to be a separate full species in its own right.
Haliotis midae Linnaeus, 1758 <br /> HALIOTIDAE<br /> South Africa, 175.1mm<br /> <br /> The "Midas Ear Abalone", locally known as "Perlemoen", is a large haliotid endemic to South Africa with a beautifully radiating wave-like sculpture. A grazing gastropod feeding primarily on encrusting algae as juveniles and a variety of seaweed and drift algae as adults, it is a common species inhabiting moderately exposed rocky shores from intertidal waters down to about -30m deep. It is the only commercially important abalone species in South Africa, traditionally harvested for the meat and exported to Asian markets where the demand for its meat is very high. Since the 1960s it started to show signs of over-exploitation, and the stocks declined rapidly after entering the 21st Century leading to the South African government closing the fishery completely in February 2008. For the same reason it was listed in CITES Appendix III by South Africa on May 2007, although it was then deleted on June 2010. Nevertheless, illegal fishing and poaching continues today and products are often exported from nearby countries such as Namibia and Mozambique. Captive-bred aquacultural business also exist, producing live specimens often seen for sale on the markets of Hong Kong and China. Its shell is commonly sold as home decor in the polished and dyed state, natural shells in good condition are surprisingly difficult to find. In its natural habitat it is usually heavily encruscted by marine overgrowth and the characteristic undulating sculpture is often completely concealed. The dorsum colouration may vary from yellowish to dark red, the internal is iridescent and often carry bluish patches in large specimens. Typical shell length around 150mm, extremely large specimens may exceed even 220mm.
Cardita crassicosta Lamarck, 1819 <br /> CARDITIDAE<br /> -10~25m, Zamboanga, Zamboanga Peninsula, Mindanao, Philippines, 2013, 45.3mm<br /> <br /> The "Large-Ribbed Cardita" is an exceedingly beautiful and colourful western Pacific carditid ranging from Taiwan to Indonesia to Australia. It is tremendously variable in colouration which can be anything from white to red to yellow to violet to very dark brown, and is therefore popular among collectors to collect a set of many specimens to exhibit the whole palette. Although it is a common species some colour forms, such as purple, are rare. The form and sculpture is generally quite consistent; specimens may or may not have dark lines on top of their base colours, in most cases between ribs but sometimes also over the ribs. A suspension feeding bivalve, it inhabits sandy bottoms of intertidal and shallow subtidal waters down to about -40m deep. Typical shell length around 45mm, extremely large specimens may exceed even 70mm.
Fissidentalium metivieri Scarabino, 1995 <br /> DENTALIIDAE<br /> -200~250m, Trawled, Madagascar, 2000/x, 126.0mm<br /> <br /> The "Metivier's Tusk" is an elegantly curved tusk shell with a restricted distribution in the southwest Indian Ocean, virtually all known specimens originate from rather deep water of -200~800m around Madagascar where it is locally not uncommon. With the largest specimens exceeding 180mm in shell length it is the largest of all currently known recent scaphopod or tusk shell species. Typical specimens are much smaller and average at around 130mm, but even that is extremely large for a scaphopod. A selective deposit-feeder like other dentaliids, it presumably feeds on small organisms such as diatoms and foramniferans and lives almost completely buried head-down in soft bottoms, leaving only the very posterior tip of its shell for water exchange and waste expulsion. It locates food using the numerous ciliated tentacles, known as captacula, surrounding the head. The captacula uses cilia to transport smaller food particles and can also retract to bring larger food items to the mouth. Although the curvedness of the shell may vary slightly, it is generally consistent in both the sculpture and the white colouration. The apex or posterior aperture is characterised by a slit-like opening in this species.
Harpa costata (Linnaeus, 1758) <br /> HARPIDAE<br /> -4~5m, Mauritius, 2009/x, 64.5mm<br /> <br /> The illustrous shell of the "Imperial Harp", with its elegantly ornamentation of numerous ribs, is arguably one of the most fascinating and elegant of all molluscs. Though it is a classic rarity chosen by S. Peter Dance as one of his fifty "Rare Shells" (1969), it was only truly rare before the early 1900s when its provenance was revaled in Mauritius. Today we know its distribution is indeed a very restricted one in the Mascarene Basin, ranging from Mauritius to Reunion to eastern Madagascar; vast majority of specimens originate from Mauritius, where it is probably best described as locally uncommon. However, as there are legal restrictions to collecting in Mauritius and the fact that high quality specimens are scarce, its price remains high and continues to be one of the most sought-after species in Harpidae. Like other Harpa species it is a carnivorous and predatory gastropod feeding on small crustaceans, mainly crabs, and it inhabits sandy bottoms of shallow water down to about -15m deep. Typical shell length around 65mm, though the largest specimen known reaches a staggering size of 111mm. Though it is an unmistakable, instantly recognisable species with a little-varied general form, the width and frequency of ribs vary greatly. This led to a form with widely spaced ribs being described as Harpa laetifica Melvill, 1916, and a form with very dense ribs was given the name Harpa multicostata Sowerby I, 1822; both are now considered to be synonyms. Another well-known synonym is Harpa imperialis Lamarck, 1822, from which its common name originate. Furthermore, a local form from southeast Madagascar with supposedly stronger-than-usual yellow colouration in the aperture was recently named Harpa costata f. lutea Bozzetti, 2012; but this was described as a form and thus carries no taxonomic validity under the current International Code of Zoological Nomenclature.
Vulsella vulsella (Linnaeus, 1758) <br /> PTERIIDAE<br /> -10~25m, Bohol Island, Central Visayas, Philippines, 2013, 80.6mm<br /> <br /> The "Sponge Finger" is a strange pteriid with a most interesting way of life of being embedded in sponges. This extraordinary sponge-bivalve relationship is obligatory and host-specific with the host being Spongia sp., an undescribed species, and is believed to be mutually beneficial to both animals. The bivalve settles on the sponge, and then remarkably loses the byssus to rely on the sponge for life, becoming endozoic. A cluster of Vulsella serves as an endoskeleton for the sponge to grow, while the sponge covers them and protect them from potential predators. Recent studies further revealed that the sponge builds an internal canal system to take advantage of the bivalve's exhalent flow and increase its own filtering rate -- the two filter-feeding species work together to gather food more efficiently. This phenomenon is commonly observed across the very wide range of V. vulsella across the Indo-West Pacific, southwards from Honshu, Japan; in shallow water around -2~30m in depth. Its shape and pattern is very variable but larger individuals tend to grow long shells resembling a finger, hence its common name. Typical shell length around 70mm, very large specimens may exceed even 115mm. Though Vulsella's true systematic position has always been a topic of debate (some even gave it its own family, Vulsellidae), it was traditionally placed in Malleidae. Recent phylogenetic studies of the superfamily Pterioidea, however, revealed it to be distant from the true Malleidae but closer related to a mixed Pteriidae-Isognomonidae clade. Isognomonidae was thus synonymised with Pteriidae, and Vulsella was moved to Pteriidae.
Ceratostoma foliatum (Gmelin, 1791) <br /> MURICIDAE<br /> -6~12m (-20~40 ft), SCUBA dived on rocks, Cuyler Harbour, San Miguel Island, Channel Islands, Off Santa Barbara, California, USA, Coll. Rick Negus, 1991/viii, 59.4mm<br /> <br /> The "Leafy Hornmouth" is a gorgeously winged northeastern Pacific murex ranging from Alaska, USA to British Columbia, Canada to California, USA; it is perhaps best known from California, where it is a representative member of a great muricid diversity. A carnivorous and predatory gastropod mostly feeding on bivalves and barnacles, it is found on rocky substrates from the lower intertidal zone down to about -60m deep. Although not uncommon, it is not easy to find a collectible specimen with both good size and wings. The colouration can range from white to dark brown with banded specimens also occuring and is variable regardless of locality. The form, especially of the varices, is very variable but more consistent according to environment and locality; for example in southern California most specimens have flat flanged varices while those from northern Channel Islands (as shown) have strongly fluted varices that resemble Ceratostoma burnetti (Adams & Reeve, 1849) from western Pacific. The extent of varice development also varies according to the environment and thus locality. Typical shell length around 60mm, very large specimens may exceed 100mm.
Foegia novaezelandiae (Bruguière, 1789) <br /> PENICILLIDAE<br /> Subtidal from sand and rubble bottom, Shelly Beach, Pallarenda, Queensland, Australia, 68.2mm<br /> <br /> Foegia novaezelandiae is a small watering-pot clam best known from Western Australia but also recorded from Japan; although it bears the name "novaezelandiae" it is actually not found in New Zealand. It is a adventitious tube-building bivalve like other members of the superfamily Clavagelloidea, which in the very earliest stages of life bears a normal bivalved shell but soon stops growing it and switches to building a calcareous tube. A locally common filter-feeding species, it inhabits soft bottoms of shallow intertidal and subtidal water to -10m deep and lives vertically buried with the "watering-pot" end down. It is unique among the family to inhait hypoxic sediments and may be associated with chemoautotrophic bacteria, which forms a thin layer on its pedal disc. The true shells are largely hidden from surface of the tube in this species, as it is mostly covered by the secreted tube material. It is the type species of genus Foegia and since a new genus, Kendrickiana, was erected to house K. veitchi (Smith, 1971) it is the only species remaining in that genus. The typical length of the adventitious tube is around 80mm, very large specimens may exceed 100mm.
Babylonia pieroangelai Cossignani, 2008 <br /> BABYLONIIDAE<br /> -160m, Trawled, East China Sea, 2015, 83.4mm<br /> <br /> Babylonia pieroangelai is a large and eye-catching babyloniid ranging from southern Japan to East China Sea to Taiwan, characterised by a strongly toothed fasciole. It was recently separated from the superficially similar Babylonia perforata (Sowerby II, 1870) based on its deeper suture, much more angulated shoulder, larger size, and more elongated form. Though still considered by some as a subspecies or even synonym of B. perforata, generally it is accepted as a valid species in its own right for now; understanding the true relationship between these two names require further evidence. Distribution of the two do not overlap, with B. perforata having a more southwesternly restricted distribution from Burma to Thailand to Cambodia. It is an uncommon carnivorous and scavenging gastropod inhabiting sandy to muddy bottoms, its depth range is around -100~200m which is very deep for the genus Babylonia. Typical shell length around 75mm, very large specimens may exceed 85mm.
Volva volva (Linnaeus, 1758) <br /> OVULIDAE<br /> Punta Engaño, Lapu-Lapu city, Mactan, Central Visayas, Philippines, 2009/viii, 136.0mm<br /> The "Shuttle volva" is an unusual ovulid with both anterior and posterior siphonal canal elegantly and distinctly extended. Thanks to these it attains the largest size of all known recent ovulids, with an average shell length of around 100mm and the very largest exceeding even 180mm; though the size is quite variable among individuals. A carnivore and an ectoparasite of octocorals, it particularly favours members of the family Veretillidae as its host. Naturally it is associated with veretillid octocorals and often found living on them, in shallow to moderately deep sublittoral water around -10~200m in depth. It is a common species with a very wide range across the Indo-West Pacific, it can be found from Eastern Africa to the southern half of Japan to Australia. Though the shell is easily recognisable, the siphonal canals are rather variable and may be strongly bent and the body whorl is sometimes weakly angulated. It should be easily separable from other recognised Volva species by its typically much longer siphonal canals.
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