Nymphaster Sladen, 1889

Nymphaster Sladen, 1889 View in CoL .

Nymphaster Sladen, 1885: 612 View in CoL (nomen nudum; diagnosed but no species named); 1889: 294; Fisher, 1917: 167; 1919: 261; Spencer and Wright, 1966: U62; Halpern, 1970: 222; 1970: 88; Downey in Clark and Downey, 1992: 253

Dorigona Perrier, 1885: 39 View in CoL ; 1894: 365; Koehler, 1909: 54 (Non Dorigona Gray 1866 View in CoL )

Diagnosis. A genus with strongly stellate body form, triangular arms with rapidly tapering, pointed tips. Abactinal surface showing weakly tabulate plates with granules covering surface. Superomarginals abutted over mid-radius along entire arm length, forming prominent frame around disk.

Comments. A widely distributed genus of Goniasteridae with 16 species in the Atlantic, Pacific, and Indian Oceans with approximately a dozen fossil species, represented primarily by ossicles from Cretaceous chalks in northern Europe (e.g. Breton, 1988). Nymphaster is a genus in need of taxonomic refinement. Both the Atlantic and Indian Ocean/Australian species, N. arenatus and N. moebi , respectively, have included one or more synonyms encompassing what has been argued as variation in each as a widespread species. In contrast, Fisher (1913, 1919) described eight species of Nymphaster from the central Pacific which have not been reviewed. Variation among Nymphaster species is widespread, as has been observed in N. moebi (see Mah, 2018) and N. arenatus ( Clark and Downey 1992) . Further efforts to test species boundaries are desirable, especially over widely distributed species.