The Echinoid Directory

Sarsiaster Mortensen, 1950, p. 155

Diagnostic Features	Test circular in outline with only faint indication of anterior sulcus; lower surface weakly convex, upper surface arched. Thin-tested. Apical disc ethmolytic with two gonopores (anterior genital plates without gonopores). Ambulacrum III sunken adapically, with small pore-pairs bearing suckered tube-feet, the tube-foot disc having a rosette of short laminae. Paired ambulacra petaloid; petals sunken and closed distally. Posterior petals generally about half the length of anterior petals. Pore-pairs not elongate, but slightly conjugate. Zones not strongly pinched as they cross the fasciole. Peristome D-shaped and slightly tilted towards anterior; with prominent lip. Labral plate longer than wide, extending to third ambulacral plate. Sternal plates symmetrical. Episternal plates offset. Periproct rounded, situated on posterior truncate face. Peripetalous fasciole present; indented by one plate behind anterior petals. Aboral tuberculation uniform and dense.
Distribution	Recent, Atlantic; 3120 m.
Name gender	masculine
Type	Sarsiaster griegii Mortensen, 1950, p. 155, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida, Hemiasterina, Hemiasteridae, ?Palaeostominae. Monotypic.
Remarks	Differs from Hemiaster in having an ethmolytic apical disc with two gonopores. Distinguished from Mecaster by having just two gonopores, not four, and more unequally developed petals than in Hemiaster. Mortensen, T. 1950. A monograph of the Echinoidea. V. Spatangoida 1. C. A. Reitzel, Copenhagen.