Nierstraszella Sirenko, 1992

Type species. Lepidopleurus lineatus Nierstrasz, 1905 . Designated by Sirenko, 1992.

Diagnosis. Valves without insertion plates. Animals of moderate size, up to approximately 20 mm length. Girdle variable, covered in small, blunt to club-shaped spicules. Valves smooth, not sculptured, but covered in thick proteinaceous layer, which may form raised pustules. Radula major lateral teeth tricuspid in juvenile specimens and bicuspid in adults.

Remarks. There are two species recognised in the genus Nierstraszella, both of which are present in the material discussed here. Sirenko (1992) established the genus Nierstraszella and synonymised seven species (the nominal taxon Lepidopleurus lineatus and six junior synonyms) in a monotypic N. lineata . All of the material illustrated in that study (Sirenko 1992) are specimens of N. lineata sensu stricto. Subsequently, N. lineata was divided into two valid species on the basis of new specimens and re-examination of the type material, reviving one junior synonym ( Lepidopleurus andamanicus) and incorporating two others under N. andamanica (Sigwart 2009b) . The specimens examined in the course of this study are the same material examined by Sigwart (2009b), which illuminated the morphological differences separating the two currently recognised species of Nierstraszella .