The Echinoid Directory

Family Trigonocidaridae Mortensen, 1903, p. 240

[ex Trigonocidarinae; =Genocidarinae Mortensen, 1942, p. 225]


 Camarodonta with:

  • apical disc dicyclic (rarely hemicyclic). Periproct subcircular with smooth edges (periproctal plates not indenting apical ring); suranal plate generally distinct amongst periproctal plates;
  • ambulacra trigeminate, with echinid style compounding; pore-pairs not expanded adorally;
  • primary tubercles in ambulacral and interambulacral zones similar in size; imperforate and weakly crenulate to non-crenulate;
  • no sharp sutural pits but test ornamented by radial epistroma or indentations around the primary interambulacral tubercles; often with strong epistromal ornamentation covering the rest of plate;
  • peristome with extremely feeble buccal notches.
?Upper Cretaceous (Turonian), Upper Eocene to Recent, worldwide.

Distinguished from Temnopleuridae by the lack of sharply defined sutural pits.

The following genus probably belongs here but is currently too poorly known to be assigned for certain: Grammechinus Duncan & Sladen, 1885

Pseudarbacina Fourtau, 1920

Mortensen, T. 1943. A monograph of the Echinoidea Part III.2, Camarodonta 1. C. A. Reitzel, Copenhagen.