Aaadonta fuscozonata ssp. depressa

Aaadonta fuscozonata depressa is a minute ground-dwelling snail for which only one live shell was found at a single locality on Ngemelis in 2005. The subspecies was previously known only from Peleliu, where three specimens were collected at two localities in 1936 by Y. Kondo. However, no specimens were found on this island in recent surveys. The species is listed as Critically Endangered, based on the limited area of occupancy, the single location, and a decline in its native habitat. Surveys to determine the current distribution of this species and population size, status and trends are recommended.

The historical geographic range of A. fuscozonata depressa was 12km². The subspecies was previously known only from Peleliu, where three specimens were collected at two localities in 1936 by Y. Kondo. The species was probably historically more abundant prior to this - indeed, substantial change had already occurred on that island by that time. The area of occupancy for this subspecies is now estimated at 1km², since few specimens have been found recently at a single locality on Ngemelis, a smaller nearby island.

A. fuscozonata depressa is threatened by destruction and modification of native lowland forest. Therefore it is not surprising that the subspecies has probably been extirpated from the highly modified island of Peleliu, whose forest was burned in World War II with flamethrowers (Hinz 1995; Crombie and Pregill 1999). Disruption of the ground, rocks and leaf litter may be of particular significance to this and other endodontid species. Endodontoid land snails are among the most threatened land snails on Pacific Islands in the few places where they still exist (Solem 1983), and therefore the fact that this subspecies is still extant is important. This subspecies is in need of conservation attention.

Field work to define the current distribution of this species, as well as research on its population status and trends, is required. Identification of priority sites for species conservation (e.g. key biodiversity areas that include threatened land snails) and reducing the impacts of human activities, especially on the small islands, is also urgently needed. The Palau Conservation Society has been supportive of recent land snail survey work in Palau.