The Echinoid Directory

• Test subpentagonal in outline; depressed; weakly concave on oral surface
• Apical disc central; plating not clear in any specimen but one shows elongate narrow posterior ocular plates with auxilliary element in between.
• Narrow auxilliary elements run down the interradius of the posterior interambulacrum
• Periproct on oral surface immediatel;y subambital; at least 6 interambulacral plates separate it from the apical disc. A narrow, slightly depressed zone of auxilliary plates extends from apical disc to periproct interradially
• Ambulacra simple and non-petaloid aborally; plates narrow and tall with pore-pairs small and oblique. Continues as simple plating to the peristome and with pores set apart
• Peristome in short well; slightly longer than wide
• Tuberculation fine and uniform

Upper Jurassic (Tithonian), Algeria

Infraclypeus thalebensis Gauthier, 1875, p. 24, by original designation. Syntypes (5): Museum National d\'Histoire Naturelle, Paris J00926.

• Only the type species

Stem group irregular

Monotypic;

Distinguished from Galeropygus by Its oral perioproct and simple ambulacra without any pore-pair differentiation.

Gauthier, V., in Cotteau, G., Peron, A. & Gauthier, V. 1875. Échinides fossiles de l'Algérie; description des espèces déja recueillies dans ce pays et considérations sur leur position stratigraphique.
Annales des Sciences geologiques 6(4), p. 25.

Gauthier, V. 1884 in Cotteau, G, Peron, A. & Gauthier, V. Echinides fossiles de l'Algerie. 2, Etages Tithonique et Neocomien. G. Masson, Paris.