The Echinoid Directory

• Test small, highly inflated, with rounded margin, gently rounded sides, pulvinate adoral surface with peristome and phyllodes depressed
• Apical system eccentric anteriorly, tetrabasal with four genital pores
• Petals long, extending almost to margin, open, narrow poriferous zones, tapering distally, pores conjugate, outer series elongate transversely; all ambulacral plates double pored
• Periproct marginal, elongate longitudinally,
• Peristome anterior, oblique, large, depressed
• Bourrelets slightly developed
• Phyllodes slightly broadened, double pored, with two series of pore-pairs in each half-ambulacrum
• No buccal pores
• No naked sternal area

Late Cretaceous (Cenomanian) of North Africa

• P. coquandi (Cotteau, 1869); Cenomanian, Algeria, Tunisia
• P. douarensis (De Loriol, 1901); Cenomanian, Algeria

Irregularia; Cassiduloida; Pygaulidae

Lambert & Thiery (1921, p. 40) and Mortensen (1948, p. 141, 143) consider Pygopistes as a synonym of Pygorhynchus. However, Kier (1962, p. 86) believes the two genera to be quite distinct. He points out that Pygopistes has a much more inflated test, with steeper sides, a more rounded marginal outline, a more pulvinate adoral surface, the apical system being more eccentric anteriorly, while the phyllodes have fewer pore-pairs.

Pygopistes differs from Pygaulus in having a more inflated test and a more anteriorly eccentric apical system.

P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp.

J. Lambert & P. Thiery. 1909-1925. Essai de nomenclature raisonnee des echinides. Libraire Septime Ferriere, Chaumont, 607 pp., 15 pls.

Pomel, A. 1883. Classification méthodique et Genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles 503, Aldolphe Jourdan, Alger, 131 pp.

T. Mortensen. 1948. A monograph of the Echinoidea: 4 (1): Holectypoida, Cassiduloida. Reitzel, Copenhagen, 363 pp., 14 pls.