This form, described in 1920, was restricted to the island of Lana’i, Hawaiian Islands.
“Specimens from Lanai differ slightly from the Molokai form. The shells are slightly smaller, more conical in outline, tapering more gradually towards a somewhat acute summit; they are darker colored and with the pale zone only indicated near the aperture. There are 16 to 18 ribs on the last whorl; the embryonic whorls, under a strong lens, are distinctly, spirally striate; the columellar fold enters obliquely, is short, almost nodule-like when viewed above, and there is usually a minute basal fold, situated deep within. Length 2.5, diam. 1.5, apert. 0.92 mm.; 5 1/2 whorls.” [1]
***
According to a study from the year 2018, all Hawaiian species of this genus are now sadly extinct. [2]
*********************
(public domain)
*********************
References:
[1] George W. Tryon; Henry A. Pilsbry; a.o.: Manual of Conchology. Second Series: Vol.25, Pupillidae (Gastrocoptinae, Vertigininae) 1918-1920
[2] Norine W. Yeung; Kenneth A. Hayes: Biodiversity and extinction of Hawaiian land snails: how many are left now and what must we do to conserve them – a reply to. Integrative and Comparative Biology 58(6): 1157-1169. 2018
*********************
edited: 25.02.2024