Pillsburiaster Halpern, 1970a

Pillsburiaster Halpern, 1970a View in CoL .

Halpern, 1970a: 2; McKnight, 1973: 180; Downey in Clark and

Downey, 1992: 258; Clark and McKnight, 2001: 102 (key).

Diagnosis. Body pentagonal in most species, weakly stellate in some (R/r = 1.4 to 2.0). Abactinal plates mound-like to flat,

weakly tabulate, arranged irregularly. Abactinal surface densely covered by numerous, coarse, spherical granules forming close clusters, obscuring plate boundaries in some species. Secondary plates present. Marginal plates numerous, 14 to 35 per interradius. Bald region, variably small to large present centrally on superomarginal plate surface, absent in one species. Furrow spines 2 to 10. Subambulacral spines 2 to 4, thick, widely spaced followed by small but coarse granules in irregular arrangement. Pedicellariae, when present, spatulate.

Comments. Pillsburiaster was described by Halpern (1970) from the Atlantic, but subsequent discoveries and taxonomic refinement have found subsequent taxa to be wide-ranging, including 10 species, three from the Indian Ocean and six from the Pacific, including the recently reassigned (Mah in prep) P. micropelta ( Fisher, 1906) and the Atlantic P. geographicus Halpern, 1970.