Monday 30 December 2013

A new species of Giant Clam.

Giant Clams of the genus Tridacna are large Bivalve Molluscs in the Cockle Family (Cardiidae). They are extremely distinctive, both for their large size and their bright colouration, which is caused by symbiotic algae that live within the flesh of their mantles. Giant Clams are found throughout the Indian and Pacific Oceans, as well as in the Red Sea. There are currently eight described species (though there is some dispute among taxonomists, as species can be hard to tell apart), seven of which are listed on the International Union for the Conservation of Nature's Red List of Endangered Species. The Clams are threatened by habitat loss, as well as overharvesting; they are taken from the wild for their edible flesh, their shells and (increasingly) for sale in the aquarium trade.

A Giant Clam in the Red Sea. Woods Hole Oceanographic Institution.

In a paper published in the journal PLoS One on 20 November 2013, a team of scientists led by Thomas Huelsken and Jude Keyse of the School of Biological Sciences at the University of Queensland publish the results of a genetic study into the phylogeny of the genus Tridacna, which unexpectedly revealed the presence of a previously unknown species of Giant Clam.

The new species was found from the Ningaloo Reef of Western Australia east to the Solomon Islands and north as far as Taiwan, and is quite possibly also to be found further afield, since the species was discovered accidentally while sampling Clams thought to be of a different species, rather than by active collecting. The new species is morphologically indistinguishable from Tridacna maxima (the Small Giant Clam), but was more closely related to Tridacna crocea and Tridacna squamosa ( The Boring and Fluted Giant Clams). 

The species is not formally named in the paper, possibly because the study was based upon genetic analysis of tissue collected from living, wild Clams, whereas the designation of a species would require a type specimen in a museum collection, to which other putative members of the same species could be compared.

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