Tag Archives: Achatinella hybrida Newcomb

Achatinella stewartii (Green)

Stewart’s Oahu Tree-Snail (Achatinella stewartii)

Stewart’s Oahu Tree Snail was described in 1827.

The shells reach sizes of about 2,2 to 2,7 cm in height; they are usually very variably colored.:

„… the ground colour is usually greenish or some shade of yellow, sometimes a single blackish coloured band accompanies the suture, sometimes this band is doubled and of different shades, and on many specimens there are two bands, one at the suture and one in the middle of the whorls. In some varieties the base of the body whorl is dark brown, the rest of the shell being of a dark form, and not unfrequently the whole shell is without any markings whatever; in which case the colour is yellow, the aperture, when inverted is ear-shaped, the truncation of the columella is rounded and thickened in a remarkable manner at its edge; along the inner margin of the outer lip there is a strong callous ridge, as in most of the species of this genus, which gradually attenuates towards the edge of the lip, which is this and sharp inside, white and pinkish round the columella.“ [1]


The species was last found in 1961 somewhere on the slopes of the Pu’u ‘ohi’a (Mt. Tantalus); it is now extinct. [2]



[1] E. W. Thwing: Reprint of the original descriptions of the genus Achatinella. Bishop Museum Occasional Papers 3(1): 1-196. 1907
[2] Recovery Plan for the O’ahu Tree Snails of the genus Achatinella. U.S. Department of the Interior Fish and Wildlife Service. Region One, Portland, Oregon. April 1993


Depiction from: ‘W. Tryon; H. A. Pilsbry; a.o.: Manual of Conchology. Second series: Pulmonata, Vol. 22, Achatinellidae 1912-1914′

(public domain)


edited: 09.06.2021