'' Idas simpsoni'', previously known as ''Adipicola simpsoni'', is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of saltwater clam, a marine

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family

Mytilidae Mytilidae are a family of small to large marine and brackish-water bivalve molluscs in the order Mytilida. One of the genera, ''Limnoperna'', even inhabits freshwater environments. The order has only this one family which contains some 52 gen ...

, the mussels. It is a deepwater species and is only found attached to the bones of dead

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

History

In 1900, some fishermen trawling the seabed between the

Hebrides The Hebrides (; gd, Innse Gall, ; non, Suðreyjar, "southern isles") are an archipelago off the west coast of the Scottish mainland. The islands fall into two main groups, based on their proximity to the mainland: the Inner and Outer Hebrid ...

and the

Shetland Islands Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the no ...

brought to the surface part of a whale skull to which was attached about twenty bivalve molluscs. They passed their find to

James Jenkins Simpson James Jenkins Simpson (24 November 1881 – 10 November 1936) was a British entomologist and marine biologist who worked in West Africa and Turkey. Background Simpson was the son of a gardener from Elgin; he studied at Elgin West End School and A ...

, a shell collector in Aberdeen, and he sent them on to the

conchologist Conchology () is the study of mollusc shells. Conchology is one aspect of malacology, the study of molluscs; however, malacology is the study of molluscs as whole organisms, whereas conchology is confined to the study of their shells. It includ ...

James Thomas Marshall James is a common English language surname and given name: *James (name), the typically masculine first name James * James (surname), various people with the last name James James or James City may also refer to: People * King James (disambiguati ...

. Marshall determined that the molluscs were new to science, and formally described them, naming the new species ''Myrina simpsoni''. Apart from one specimen which was found inside a baulk of drifting

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

wood, all specimens seen since then have been associated with the skeletons of dead whales, making this mollusc the first known species with such a restrictive habitat requirement. The species has since been transferred to the genus ''

Idas In Greek mythology, Idas (; grc, Ἴδας, Ídas), was a Messenian prince. He was one of the Argonauts, a participant in the hunt for the Calydonian Boar and contender with the gods. Idas was described as keen and spirited.Hyginus, ''Fabulae ...

'', making it ''Idas simpsoni''.

Description

This mollusc can grow to a length of about . The shell is equivalved, oblong and rather fragile, the posterior end being broad and rounded while the anterior end is narrower and more acutely pointed. The dorsal margin is flat and the hinge simple; the shell is embossed with fine concentric sculpturing. The exterior of the shell is grey and the interior is pearly.

Ecology

whale fall A whale fall occurs when the carcass of a whale has fallen onto the ocean floor at a depth greater than , in the bathyal or abyssal zones. On the sea floor, these carcasses can create complex localized ecosystems that supply sustenance to deep-s ...

, the sinking of a dead whale carcase to the sea floor, creates a complex localized ecosystem that can supply sustenance to deep-sea organisms for long periods of time. ''Idas simpsoni'' is described as living in abundance on weathered whale skulls.

References

{{Taxonbar, from=Q13358782 Mytilidae Molluscs of the Atlantic Ocean Molluscs described in 1900