The Echinoid Directory

Contributed by Andrew Smith, August 2011

Tiaridia Pomel, 1883, p. 97

Diagnostic Features	(From Pomel, 1883) Test small, inflated Apical disc monocyclic Ambulacra weakly heterogeneous, with small tubercles developed adorally and just mamelonate granules adapically. Pore-zones uniserial throughout, plating trigeminate Tubercles perforate and crenulate Interambulacral plates with large primary tubercle with scrobicular circle; perforate and crenulate.
Distribution	Cenomanian, Upper Cretaceous, Algeria.
Name gender	feminine
Type	Hemicidaris batnensis Cotteau 1867, p. 395, by monotypy.
Species Included	Only the type species
Classification and/or Status	Camarodonta, Glyphocyphidae Monotypic
Remarks	The apical disc was later figured in Cotteau Peron & Gauthier (1878) Cotteau, G. 1867. Echinides nouveaux ou peu connus. Revue et Magazin de Zoologie serei 2, 19, 392-406. Cotteau, G. Peron, A. & Gauthier, V. 1878. Echinides fossiles de l'Algerie 4, Etage Cenomanien. G. Masson, Paris. Pomel, A. 1883. Classification methodique et genera des echinides vivants & fossiles. Thesis presentees a la Faculte des Sciences de Paris. Alger, A. Jourdan.