The Echinoid Directory

Echinopygus d\' Orbigny, 1836, p. 303

[?=Echinanthites Leske, 1778, p. 194 (nomen nudum) ]

Diagnostic Features
  • Test large, length greater than width, margin angular with posterior greatly prolonged, aboral surface inflated with greatest height anterior to centre at apical system and with steeply sloping sides; greatest width posterior to centre; adoral surface concave.
  • Apical system anterior, tetrabasal, with four genital pores.
  • Petals broad and lanceolate, equal, long, extending over two-thirds distance to margin, with very wide interporiferous zones, strongly tapering distally.
  • Poriferous zones narrow, inner pores weakly oval, outer pores slit-like.
  • Periproct inframarginal, tear-drop shaped, with apex pointing adorally, width approximately equal to length.
  • Peristome anterior, pentagonal, slightly higher than wide.
  • Bourrelets strongly developed and tooth-like.
  • Phyllodes double pored, expanding towards peristome, distinctly depressed between bourrelets; one series of pore pairs in each half-ambulacrum with a wide space between series; pore pairs widely separated from edge of peristome.
  • No buccal pores; sphaeridial pits forming a double perradial series.
Distribution
Cretaceous (Valanginian - Cenomanian), Europe, Central and South America, Jurassic of East Africa.
Name gender masculine
Type
Clypeaster oviformis var. 2 Lamarck, 1816, p. 15 [=Echinoaus lampas de la Beche, 1819, p. 42], by subsequent designation of Lambert and Thiery 1921, p. 355.
Species Included
  • E. lampas (de la Beche, 1833); Cenomanian, France and England.
  • E. rostratus (L. Agassiz, 1839); Valanginian, western Europe.
  • E. tinoocoi Beurlen, 1966; Cenomanian, Late Cretaceous, Brazil.
  • E. jageuyanus Cooke, 1955; Albian, Early Cretaceous, Columbia.
Classification and/or Status
Irregularia; Neognathostomata; pygurid grade stem group.
Remarks

Echinopygus has previously been considered a synonym of Pygurus (Kier, 1962, p. 46) and assigned to the Clypeidae. The Clypeidae have phyllodes that are broad and double pored, with pore pairs forming arcs of two or three in each half-ambulacrum. Echinopygus has only a single series of double pores in each half-ambulacrum, and very tooth-like bourrelets.

D'Orbingy, A. 1854-60. Paléontologie Française. Terrains Crétacés. Tome 6. Echinodermes, Échinoides irréguliers. 596 pp, pls 801-1006. G. Masson, Paris. 1-32 (July 1854); 33-64 (Oct. 1854); 65-96 (Nov. 1854); 97-128 (Jan. 1855); 129-192 (Mar. 1855); 193-208 (May 1855); 209-224 (Aug. 1855); 225-272 (Nov. 1855); 273-320 (Oct. 1856) pp. 273-352 (Oct. 1856), pp. 353-384 (1857), pp. 385-400 (1858), pp. 401-432 (1858), pp. 433-596 (1860).

D\'Orbigny established the genus Echinopygus for the species Pygurus lampas and Pygurus rostratus. The type species was redescribed and figured by Smith & Wright (2000).

Smith, A. B. & Wright, C. W. 2000. British Cretaceous echinoids. Part 6. Neognathostomata (Cassiduloids). Monograph of the Palaeontographical Society 391-439, pls 130-138.