Thaanum’s Amastra Snail (Amastra thaanumi) 

Thaanum’s Amastra Snail was described in 1911, it was restricted to a place named Ka’a’awa in the Koʻolauloa District on the northeastern coast of O’ahu, Hawaiian Islands.

The species was described on the basis of a single living specimen and several dead shells.

… from the description.:

“The shell is sinistral, imperforate, moderately solid, oblong, having a somewhat silky luster. Spire widely conic with somewhat convex outlines and rather obtuse summit. Embryonic whorls marked with faint, very fine growth-striae only; later whorls distinctly striate obliquely, the striae fine and somewhat thread-like. Upper whorls purplish-brown ith irregular whitish streaks, the last two whorls covered with a rich dark chestnut cuticle, yellowish next the suture, and deciduous in front of the aperture, showing a glossy light green under layer. Aperture rather oblique, livid or bluish white whithin, with a whitish callous rim within the dark-edged lip. Columella short, bearing a strong, triangular, downward-bent lamella. Parietal callus thin.“

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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: 28.09.2020