The Echinoid Directory

Gregoryaster Lambert, 1907, p. 59

Diagnostic Features	Test subcircular to ovate with shallow anterior sulcus; posterior face truncate. Test wedge-shaped in profile. Apical disc ethmolytic with four gonopores; central. Ambulacrum III in sulcus aborally which shallows close to the ambitus. Pore-pairs with enlarged periporal bulge; closely spaced and presumably associated with funnel-building tube-feet. Paired ambulacra petaloid; petals long, straight and sunken. Anterior petals widely diverging; posterior pair almost as long as anterior pair. Peristome close to anterior border. Labrum short and quadrate; sternal plates large and triangular; symmetric; forming most of oral surface. Episternal plates biserially offset. Periproct towards top of posterior truncate face. Peripetalous fasciole present, indented by two interambulacral plates behind the anterior petals and crossing plate 5 in interambulacra 1b and 4a. Traces of a thin marginal fasciole is variably present around the posterior of the test.
Distribution	Upper Cretaceous (Maastrichtian), India; ?Eocene, Spain; Miocene, circum Mediterranean.
Name gender	masculine
Type	Pericosmus coranguinum Gregory, 1892, p. 615, by original designation.
Species Included	Although Lambert & Thiery (1921) included many species from Upper Cretaceous to Miocene in age in this taxon, they did not realise the type species has traces of a posterior marginal fasciole. Consequently, few of species they list can be included for certain at present. \'Trachyaster\' heberti Cotteau, 1890 probably belongs here. G. expansa (Forbes, 1856); Campanian-Maastrichtian, southern India
Classification and/or Status	Spatangoida, Paleopneustina, Schizasteridae.
Remarks	Differs from Hemiaster in having long, narrow subequal petals in well defined grooves and in having the peripetalous fasciole indented behind the anterior petals by two plates and crossing the anterior interambulacra on plate 4. The lateroanal part of the marginal fasciole is variably developed, but traces can be seen in the holotype. It differs from Faorina in having no second branch to the peripetalous fasciole anteriorly, in having four rather than three gonopores, and amphiplacous plating adorally. Opissaster is basically similar but has no trace of the marginal fasciole and has much shorter posterior petals than anterior petals. Lambert, J. 1907 (for 1906). Etude sur les echinides fossiles de la molasse de Vence. Annales de la Societe des Lettres des Sciences et des Arts de l'Alpes Maritimes 20, 64 pp., 10 pls.