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The Echinoid Directory

Pygurostoma Cotteau & Gauthier, 1895, p. 51

Diagnostic Features
  • Test of medium to large size, oval, elongate, low, greatest width posterior of centre. Anterior margin rounded, slight tapering posteriorly; adoral surface slightly depressed towards peristome.
  • Apical system slightly anterior, tetrabasal, with four gonopores. Genital plates other than G2 very small.
  • Petals broad, long, equal, tapering distally but not closed. Pores conjugate, ambulacral plates beyond petals with single pores.
  • Peristome transverse, pentagonal.
  • Periproct inframarginal, longitudinal, associated with a small but distinct subanal indentation.
  • Bourrelets well developed, blunt and tooth-like; basicoronal plates longer than wide.
  • Phyllodes broad with a distinct outer and inner series in each half-ambulacrum, plus a broad scattering of pores in between.
  • Buccal pores present, but very small and rudimentary.
  • Very narrow, smooth tubercle-free granular zones both anterior and posterior of peristome.
Distribution
Upper Cretaceous (Senonian-Maastrichtian) of Iran, United Arab Emirates and possibly Central America (Kier & Lawson, 1978).
Name gender neuter
Type
Pygurostoma morgani Cotteau & Gauthier, 1895, p. 51; by monotypy.
Species Included
  • P. morgani Cotteau & Gauthier, 1895; Maastrichtian, UAE, Senonian of Iran.
  • ? P. pasionensis Cooke, 1949; Campanian, Guatemala.
Classification and/or Status
Irregularia; Cassiduloida; Faujasiidae; Faujasiinae.
Remarks

Pygurostoma is distinct from other faujasiids due to its densely pored phyllodes. Gongcrochanus has a similar floscelle, but has a supramarginal periproct and a more inflated test. The type species was redescribed by Smith (1995).

The species Pygurostoma pasionensis described by Cooke (1953) may belong here, but has more the appearance of Clypeolampas because of its parallel-open-ended petals.

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

C. W. Cooke. 1953. American Upper Cretaceous Echinoidea. Geological Survey Professional Paper 254-A, 1-43, pls 1-16.

Cotteau, G. & Gauthier, V. 1895. Mission scientifique en Perse par J. de Morgan; études géologiques des échinides fossiles. Volume 3, 1-107. E. Leroux, Paris.

A. B. Smith. 1995. Late Campanian-Maastrichtian echinoids from the United Arab Emirates-Oman border region. Bulletin of the Natural History Museum, London (Geology Series) 51(2), 121-240.