Nanopsis Henningsmoen, 1954

Salas, María José & Vaccari, N. Emilio, 2012, New insights into the early diversification of the Ostracoda: Tremadocian ostracods from the Cordillera Oriental, Argentina, Acta Palaeontologica Polonica 57 (1), pp. 175-190 : 182

Genus Nanopsis Henningsmoen, 1954

Type species: Beyrichia nanella Moberg and Segerberg, 1906 . Ceratopyge Shale , Ventlinge , Öland, Sweden; original designation. Late Tremadocian .

Species included: Nanopsis coquena Salas, Vannier, and Williams, 2007 , and Nanopsis pilloides ( Schallreuter, 1998) .

Discussion.— Nanopsis is characterized by a very simple morphology of nodes and sulci restricted to the dorsal half of the valves, and by the absence of any marginal structures. So far three species would be included in the genus: Nanopsis nanella ( Moberg and Segerberg, 1906) from the Baltic region ( Henningsmoen 1954; Tinn and Meidla 2004), Nanopsis coquena Salas, Vannier, and Williams, 2007 from the northwest of Argentina ( Salas et al. 2007) and Bumire pilloides Schallreuter from Western Australia ( Schallreuter 1998). Bumire Schallreuter, 1998 is a monospecific genus from the Floian of Australia that shares with Nanopsis its main features, suggesting that it should be regarded as a junior synonym of Nanopsis . Both forms share the same simple morphology. The valves are subelliptical and amplete to slightly postplete. They are bi or tri sulcate, the sulci are restricted to the dorsal half of the valves, S1 is poorly developed, S2 is the deepest and longest sulcus and S3 is poorly defined if it is present. Admarginal structures and dimorphism are absent.

Salas et al. (2007) also mentioned a possible synonymy with a Chinese Tremadocian species, however, the confirmation of this demands further analysis.

Stratigraphic and geographic distribution.— Norway and Sweden, and northwest Argentina in Tr2 ( Paltodus deltifer Biozone ), and Western Australia in Floian. Possibly in the Tremadocian of China.