The Palau Islands, as far as it is known, are home to three endemic tree-snail species, the Calypso Tree-Snail (Palaopartula calypso (Semper)), the Leucothoe Tree-Snail, and the Thetis Tree-Snail (Palaopartula thetis (Semper)), all of which seem to have originally been collected on the island of Peleliu.
These three species are most closely related to the species that live in Melanesia, yet form their own subgenus (Palaopartula), which has now been elevated to full genus status. [3]
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During field surveys in the year 2005, only one species, the Calypso Tree-Snail, could be relocated.
The notorious ‘snail killers’ (Rosy Wolfsnail (Euglandina rosea (Férussac)), Snail-eating Flatworm (Platydemus monokwari (De Beauchamp)) et al.), that have been introduced to so many islands, seem to haven’t yet reached the Palau Islands.
The Leucothoe Tree-Snail is, however, nevertheless, most likely extinct.
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References:
[1] Rebecca J. Rundell: The land snails of Belau: Survey of the 16 States. Report. Distributed to Federal, State and Local Governments and NGOs, Republic of Palau. 2005 [2] Ric Brewer; Jesse Czekanski-Moir; Rebecca J. Rundell: Partula Programme Consortium and Belau Partulidae update. Tentacle 15: 19-20. 2007 [3] Justin Gerlach: Icons of Evolution: Pacific Island Tree-Snails of the Family Partulidae. Phelsuma Press 2016 [4] John Slapcinsky; Fred Kraus: Revision of Partulidae (Gastropoda, Stylommatophora) of Palau, with description of a new genus for an unusual ground-dwelling species. ZooKeys 614: 27-49. 2016
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Photo from: ‘John Slapcinsky; Fred Kraus: Revision of Partulidae (Gastropoda, Stylommatophora) of Palau, with description of a new genus for an unusual ground-dwelling species. ZooKeys 614: 27-49. 2016’
The nominate race of this species was restricted to the island of Peleliu, Palau Islands.
The shells reached an average size of 0,19 to 0,24 cm in diameter.
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The majority of the habitat of this, and other snail species from the island of Peleliu, was destroyed during World War II, when large areas of the island forests were destroyed – by the summer of 1944 the island was occupied by about 11000 Japanese soldiers, which had entrenched themselves in subterranean tunnel systems. The US-Army, which landed on the island in the September of the year 1944, deployed flamethrowers and grenades, but also napalm bombs, to deforest the Japanese positions.
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Field searches in the years 2003, 2005, and 2007 were unsuccessful, and this form is now most probably extinct.
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References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part II, Families Punctidae and Charopidae, Zoogeography. Field Museum of Natural History Chicago, Illinois 1983
