Sunday 30 September 2012

A new species of Pachychilid Snail from western Java.

Pachychilid Snails are freshwater Gastropods found throughout the tropics. They have thick shells and operculi (plates used to cover the entrance of the shell) enabling them to live in turbulent waters. Many species give birth to live young, rather than laying eggs. Their closest relatives are marine Gastropods not other freshwater forms.

In a paper published in The Raffles Bulletin of Zoology on 29 February 2012, Ristiyanti Marwoto and Nur Isnaningsih of the Museum Zoologicum Bogoriense at the Research Center for Biology in Cibinong, West Java, describe a new species of Pachychilid Snail from the River Cibangbay in Tasikmalaya, West Java.

Map of Java showing the site where the new species was found (star) as well as known sites where the closely related Sulcospira testudinaria occurs. Marwato & Isnaningsih (2012).

The new species is placed in the genus Sulcospira, which is found in fast moving streams and rivers throughout south China, Southeast Asia and western Indonesia. It is given the specific name kawaluensis, which refers to the Kawalu Subdistrict, where the snails were found. Sulcospira kawaluensis is a 10-28 mm dark-coloured Snail with a roughly oval shell, comprising four-to-six flattened whorls in the adults, though this is the result of earlier whorls being worn away rather than only this number being produced. The Snails were found living on stones at depths of ~40 cm in an area of the Cibangbay which also had sandy and gravely areas. The species was largely distinguished from its closest relative, Sulcospira testudinaria, on the basis of the teeth on its radula (the radula is the tongue of a Gastropod, it is covered in hooked teeth, used to scrape up food).

Sulcospira kawaluensis. (D) Is the operculum. Other pictures are the whole shell. Scale bar is 10 mm. Marwato & Isnaningsih (2012).

The raduli of Sulcospira kawaluensis (Top) and Sulcospira testudinaria (Bottom). Images on the left are taken from directly above, those on the right from behind at an angle of 45°.

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