Anatomy, relationships and distribution of Taiwanassiminea affinis (Bottger) (Caenogastropoda: Assimineidae), with a reassessment of Cyclotropis Tapparone-Canefri

Assiminea affinis (Mousson ms) Bottger, 1887(=A. queenslandica [Pilsbry ms] Thiele, 1927), a previously unrecognised Australian assimineid species, is described anatomically and allocated to the genus Taiwanassiminea Kuroda and Habe, 1950, first described from Taiwan. This is the first record of the genus from Australia. Taiwanassiminea affinis is found in slightly brackish waters in the upper tidal reaches of the larger rivers from northern Queensland to the Shoalhaven River in the southern half of New South Wales. The terrestrial Cyclotropis Tapparone-Canefri, 1883, which has somewhat similar shell and radular characters, is redefined and several species (Assiminea bedaliensis Rensch, 1934; Paludinella javana Thiele, 1927; Assiminea lentula, A. riparia and A. sororcula, all Benthem Jutting, 1963) previously included in Cyclotropis are transferred to Taiwanassiminea.