Extinct Amastra Snail (Amastra extincta)

The Extinct Amastra Snail was scientifically named for the fact that it was already extinct for a long time when it was described in 1855.

The species is known exclusively from subfossil specimen collected somewhere on the island of O’ahu, Hawaiian Islands.

… from the original description.:

“Shell perforate, ovate-turrite, solid, striatulate, chalky. Spire long, tapering upwards, acute. Whorls 7, scarcely convex, the last less than one-third the total length, somewhat compressed around the perforation. Aperture slightly oblique, rhombic-oval, angular at the base. Columellar fold compressed, ascending almost from the base. Peristome simple, unexpanded, the margins joined by a thick, somewhat nodiferous callus, columellar margin dilated, free.” [1]

The shells reached sizes of about 1,6 cm in length. [1]

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References:

[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata. Vol 21: Achatinellidae (Amastrinae). 1911

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edited: 27.09.2020