Angustassiminea castanea is a species of small operculate snail, a terrestrial gastropod mollusk or micromollusk in the family Assimineidae.
Description The length of the shell attains 5 mm, its diameter 2.5 mm.
(Original description in Latin) The solid shell is imperforate, pyramidally conical and chestnut-colored. It is very shiny, finely striate and spirally lined. The spire is acute. The shell has seven rather convex whorls, which are disjoined by a thin suture. The body whorl is faintly angled, convex at the base, and it nearly occupies half the length of the shell. The aperture ispear-shaped and acute above, with a straight parietal wall. The peristome (margin) is straight, with a arched basal margin. The inner lip is slightly thickened and reflected above.
Distribution This marine species has been found off Japan.
References
Kuroda, T. (1958). On the more species of Assiminea from Japan (A feshwater gastropodous genus). Venus. 20(1): 16-22. Fukuda H. & Hasegawa K. (2017). Family Assimineidae. Pp. 813-816, in: T. Okutani (ed.), Marine Mollusks in Japan, ed. 2. 2 vols. Tokai University Press. 1375 pp.