The Echinoid Directory

Petalaster Cotteau, 1885, p. 330

Diagnostic Features	Test relatively small (~ 25 mm), subcircular to ovate in outline, moderately depressed, with a rounded margins. Apical system anterior, with four gonopores. Ambulacrum III non-petaloid, other ambulacra petaloid with broad petals, tapering distally, and conjugate pores. Peristome slightly anterior, transverse, oval. Periproct marginal to inframarginal, transverse, oval. Bourrelets not developed; peristome sunken. Phyllodes simple, single pored. Buccal pores present.
Distribution	Originally recorded as Upper Senonian, Tunisia; age later confirmed as Upper Eocene by Cotteau (1887).
Name gender	masculine
Type	Petalaster maresi Cotteau, 1885, p. 330; by monotypy.
Species Included	Only the type species.
Classification and/or Status	Irregularia; Neognathostomata, Plesiolampadidae. Subjective junior synonym of Pseudopygaulus Coquand, 1862.
Remarks	Cotteau (1887, p. 468-469) states that when he erected his genus Petalaster he was unaware that Coquand had named a new genus (Pseudopygaulus) for Pseudopygaulus trigeri, a species that Cotteau considered congeneric with his Petalaster maresi. Cotteau therefore placed his Petalaster in synonymy under Pseudopygaulus. Kier (1962, p. 222) reports that he believes that P. maresi and P. trigeri are so similar that they are certainly congeneric, possibly conspecific. P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections 144, (3), 262 pp. Cotteau, G. 1884. Echinides nouveaus ou peu connus. Bulletin de la Societe Zoologique de France, 7 (3), pp. 37-51, pls 5 & 6 (plate 5, fig. 7).