Rosy Oahu Tree Snail (Achatinella rosea)

The Rosy Oahu Tree Snail was described in 1828, the species inhabited the Helemano- and Poamoho Ridges and adjacent places at the western slopes of the Ko’olau Mountains in eastern O’ahu, Hawaiian Islands.  

The shells reached heights of about 1,9 to 2,2 cm, they are white or pale rosy to strong pink or sometimes brown, unicolored or multicolored striped; many, but yet not all individuals of this species have a strong pink colored shell aperture (mouth).  

We also have some information about the appearance of the actual animal.:

“Animal, when young, of a bright straw yellow, with ocular appendages tinged with brown. In the adult, the color is a uniform light gray, with mantle and tentacles dark brown.” [1]

This is also considered some kind of variety or maybe subspecies of the Bulimus-like Oahu Tree Snail (Achatinella bulimoides Swainson).

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The last record for this species was the sighting of a single individual at the Helemano Ridge in 1949, since then the species is considered extinct. [2]

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Parts of the former range of the Rosy Oahu Tree Snail are still inhabited today by another tree snail species, Sowerby’s Oahu Tree Snail (Achatinella sowerbyana Pfeiffer) that somehow still manages to survive in the wild.  

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References:

[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

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edited: 08.06.2021