The Echinoid Directory

Pygorhynchus L. Agassiz, 1839, p. 53, 99

[=Botriopygus d'Orbigny, 1856, p. 344; type species Catopygus obovatus L. Agassiz, 1836, p. 136; by subsequent designation of Cotteau, 1869, p. 121 (objective)]

Diagnostic Features	Test of medium to large size, with greatest width posterior to centre, anterior margin blunt, posterior pointed, low, or in a few species moderately inflated Apical system anterior, tetrabasal, with four genital pores Petals well developed, broad, closing distally, narrow poriferous zones with conjugate pores, all ambulacral plates double pored Periproct marginal to inframarginal, longitudinal Peristome anterior, depressed, oblique or regular Bourrelets well developed Phyllodes double pored, slightly broadened, with two series in each half-ambulacrum; 8 to 10 in each outer series, 3 to 5 in each inner series No buccal pores
Distribution	Early Cretaceous (Valanginian-Albian) of Europe, North Africa and the Americas.
Name gender	masculine
Type	Catopygus obovatus L. Agassiz, 1836, p. 136; by subsequent designation of Lambert, 1898, p. 162.
Species Included	P. obovatus (L. Agassiz, 1836; Valanginian, Europe Lambert & Thiery (1909-1925) list 3 species within this genus.
Classification and/or Status	Irregularia; Cassiduloida; Pygaulidae
Remarks	Pygorhynchus is similar to Pygaulus. Kier (1962, p. 83) reports that both genera have similar petals, an oblique peristome and a longitudinal periproct. Pygaulus can be distinguished from Pygorhynchus by the shape of its test being generally high, with a smoothly rounded anterior and posterior margin, parallel sides and inframarginal periproct. In Pygorhynchus the test is generally lower, the posterior pointed, with sides not parallel, but expanding posteriorly, and the periproct being more marginal in its position. Pygorhynchus also has more developed phyllodes than Pygaulus. Pygorhynchus is also quite similar to Parapygus (Kier, 1962, p. 83). Pygorhynchus is distinguished by its double-pored phyllodes and its lack of buccal pores, in contrast to the single pored phyllodes with buccal pores present in Parapygus. Differs from Hypopygurus Gauthier, 1889 only in lacking clear buccal pores. Agassiz, L. 1839. Description des Échinodermes fossiles de la Suisse. Première partie, Spatangoides et Clypéasteroides. Mémoires de la Société helvétique des Sciences naturelles, 3, i-viii + 1-101, 14 pls. 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.