The Echinoid Directory

Thierychinus Lambert, 1911, p. 29

Diagnostic Features
  • Test subconical with rounded ambitus.
  • Apical disc small (<17% test diameter); plating unknown.
  • Ambulacra straight, about 70% width of interambulacra. Plating trigeminate; plate compound style unknown.
  • Pore zones forming two columns at ambitus and above, with two pore-pairs in outer and one in inner series; the outer series of offset pore-pairs separated from an inner series by a tubercle. Inner pore-pairs distinctly smaller. Each compound plate with two or three subequal tubercles identical to those of the interambulacra.
  • Interambulacra wide, composed of many wide plates each bearing two irreular rows of small, subequal tubercles. Tubercles imperforate and non-crenulate without a platform; areoles not differentiated. Tubercles become distinctly larger beneath the ambitus.
  • Interradial zone forming a narrow naked band adapically.
  • Peristome large; ca. 60% test diameter; buccal notches modest.
  • Spines and lantern unknown.
Middle Jurassic (Bajocian), France.
Name gender masculine
Thierychinus delaunayi Lambert, n.sp. 1911, (later described in Lambert & Thiery, 1914, p. 244, pl. 6, figs 5-7), by original designation. Holotype: Museum National d'Histoire Naturelle, Paris J00789.
Species Included
  • Only the type species.
Classification and/or Status

Euechinoidea, Echinacea, Stomechinidae.



Distinguished from Polycyphus by having a distinct inner series of pore-pairs separated from the outer band by a zone of tubercles.

Lambert, J. 1911. Sur trois genres des Echinides nouveaux. Annales de la Societe Linneenne Lyon 57, p. 29.

Lambert, J. & Thiery, P. 1909-1921. Essai de nomenclature raisonnee des echinides. Chaumont, Ferriere