Minamijima Mandarina Snail (Mandarina luhuana ssp. minamijimana)

The Minamijima Mandarina Snail was described in 2007, it is known exclusively from Holocene deposits on the island of Minamijima, Ogasawara Islands, Japan; it was originally thought to be identical with Mandarina luhuana (Sowerby) and was named as Mandarina luhuana f. A Chiba. 

The shells reach sizes of about 2.2 cm in height and up to 4.2 cm in diameter; they differ from those of the nominate race in having a higher spire, a smaller number of whorls, a relative narrower umbilicus and a thinner shell, the shells are furthermore darker in color. [1]

“Many fossil specimens of this species are found in the sand dune.” [1] (see also photo below)

The species likely disappeared at the Pleistocene/Holocene border due to natural climate changes.

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References:

[1] Tadashige Habe: Fossil land snails from Minami-jima, Bonin Islands. Science Reports of the Tohoku University, Special Volume 6 (Hatai Memorial Volume): 51-53. 1973
[2] Satoshi Chiba: Taxonomic revision of the fossil land snail species of the genus Mandarina in the Ogasawara Islands. Paleontological Research 11(4): 317-329. 2007

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edited: 27.02.2024