Theodoxus (Clithon) oualaniensis Lesson, 1830

A rather large colony of Theodoxus (Clithon) oualaniensis Lesson, 1830 was living on the beach of Teluk Dalam (Pulau Perhentian, Malaysia) at the mouth of a little river. At low tide, the nerites were in the fresh water coming from the river, at high tide they were covered by the sea. They were mixed with gravel of same size as the snails. Although there was a great polymorphism in this population, the predominant colour, yellow-orange, was the one of the gravel. In 2003, I was only able to find dead shells.

First of all, Theodoxus (Clithon) oualaniensis was described by Lesson in 1830 in "Voyage de la coquille" and not 1831 as it is often mentioned .

Clithon oualaniensis
Clithon oualaniensis

As mentioned in the description the shell was first found on an island called Oualan which is in Micronesia. Oualan is now known as Kosrae.

The polymophism the species is well-known. Here is a page from Martini et Chemnitz, 2nd ed., 1879.

Click on the pictures for a closer view

Clithon oualaniensis
Clithon oualaniensis

EN CONSTRUCTION


Click on the pictures for a closer view
Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis
T1 • Fine axial pattern T2 • T3 • T4 • T4 • T5 •

Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis
£
T6 •
T6 • T7 • T8 • T9 • T10 •

Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis Clithon oualaniensis
T11 • T12 • T13 • T13 • T13 •

Link to the
Obis Indo-Pacific molluscan database page for this species :
Theodoxus (Clithon) oualaniensis Lesson, 1830


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Last update 3/10/06
© Copyright 2006 Sophie Valtat