St. John’s Mautodontha Snail (Mautodontha saintjohni)
This species was described in 1976; it was endemic to the island of Bora Bora in the Society archipelago.
The shells reach about 0,26 to 0,3 cm in diameter; they are white and bear prominent zigzag-shaped, reddish flammulations.
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References:
[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
The oldest known specimen of this species was collected on the island of Tahiti, Society Islands in 1769 during Cook’s first voyage around the world, the species was subsequently collected only five more times with the last specimen having been taken around 1850.
The species was apparently more widespread in the Society Islands, as at least one specimen was found on the island of Bora Bora, this was described as a distinct species in 1981, however, was later downgraded to synonymous status. [1]
The Tahitian Pavonia disappeared at the middle of the 19th century.
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References:
[1] F. R. Fosberg; M.-H. Sachet: Pavonia (Malvaceae) in the Society Islands. Bulletin du Muséum National d’Histoire Naturelle 4 sér. 3, section B, Adansonia 1: 15-18. 1981
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Depiction from: ‘Sydney Parkinson: A Journal of a Voyage to the South Seas, in his Majesty’s Ship the Endeavour. London: Stanfield Parkinson 1773’
This variably colored species was described in the year 1831.
The species was endemic to the island of Bora Bora, Society Islands, where it was the only member of its genus, and where it was still numerously found in the 19th century on the stems, branches, and leaves of the native vegetation.
The shells reached a height of nearly 2 cm and was usually pale yellowish to light brown with the apex being of the same color or slightly darker.
The Yellow Tree-Snail is now extinct. [1]
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The same species was introduced to the island of Maupiti sometimes after 1929, from where it is known, however, only from subfossil shells, found and photographed in 2010, 2012 and 2017 by J.-F. Butaud, J. Gerlach and others.
The species is extinct on Maupiti as well. [1][2]
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References:
[1] Justin Gerlach: Icons of Evolution: Pacific Island tree-snails, family Partulida, Phelsuma Press, Cambridge U.K. 2016 [2] Justin Gerlach: Partula survival in 2017, a survey of the Society Islands
