The Echinoid Directory

Heteronucleus Lambert, 1911, p. 184

Diagnostic Features
  • Test small, oblong, low, with greatest height anterior to centre.
  • Apical system, anterior, tetrabasal, oculars large, posterior oculars in contact with each other, madreporite large, with four genital pores; genital plate 2 much larger than other genital plates.
  • Petals broad, open, parallel; petals II, II and IV extending almost to the margin, petals I and V extending two-thirds distance to margin. Interporiferous zones broad, twice the width of the poriferous zones. Pores conjugate, the two pores elongated transversely.
  • Nature of ambulacral pores beneath petals unknown.
  • Periproct supramarginal, two-thirds distance from the apical system to the posterior margin, longitudinal in a slight groove.
  • Peristome anterior - its shape unknown, covered with matrix in holotype.
  • Floscelle - unknown.
Upper Cretaceous (Senonian), Algeria.
Name gender masculine
Heteronucleus peroni Lambert, 1911, p. 184; by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Irregularia; Cassiduloida; Indeterminate.

Monotypic. Incertae sedis.


Lambert erected this genus because he thought that ambulacrum III was non-petaloid in the type species. There is only one specimen of the type species, located in the Lambert collection, Paris. Kier (1962, p. 64) reports that he studied the holotype, and believes that ambulacrum III was petaloid originally, but owing to the poor preservation of the anterior of the holotype, most of this petal is missing. In the absence of information concerning whether ambulacral pores are single or double beneath the petals it is impossible to place this genus.

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

Lambert, J. 1911. Note sur quelques echinides eoceniques des Corbieres septentrionales. Annales de l'Universite de Lyon 30, p. 184.