The Echinoid Directory

Tetraromania Solovjev, 1971, p. 64

Diagnostic Features
  • Test ovate with weak frontal sulcus at ambitus that continues to the peristome.
  • Apical disc widely disjunct. Four gonopores; the posterior two gonopores placed on ocular plates II and IV. Genital plates 1 and 4 rudimentary or lost.
  • Posterior ocular plates some distance anterior of the periproct.
  • Ambulacra flush; all five ambulacra apetaloid aborally.
  • Plastron meridosternous; paired interambulacra amphiplacous.
  • Peristome small, subcircular, without labral projection.
  • Periproct inframarginal, at end of slightly projection.
  • Aboral tuberculation of scattered primary tubercles set in a groundmass of fine granules. Protofasciole encircles the periproct.
Lower Cretaceous (Berriasian to Barremian), Europe, former USSR.
Name gender feminine
Dysaster ovulum Desor, 1842, p. 22, by original designation. Holotype: Museum National d'Histoire Naturelle, Paris J01258.
Species Included
  • T. ovulum (Desor, 1842); Barremian, Europe, former USSR.
  • T. jaccardi (Desor, 1869); Hauterivian, Europe, USSR.
  • T. sp. Solovjev, 1971; Berriasian-Valanginian, former USSR.
Classification and/or Status

Irregularia, stem group Atelostomata, Tithoniidae.



Distinguishes from the very similar Tithonia by having the posterior oculars placed at some distance anterior to the periproct, and in having the labral plate in contact with two succeeding plates. Corthya has the same apical disc structure and a similar plastron plating, but differs in having a higher periproct and a shallow anterior sulcus.

Solovjev, A. 1971. Late Jurassic and Early Cretaceous disasterids of the USSR. Transactions of the Palaeontological Institute, Academy of Sciences of the USSR 131, 1-120, pls 1-16 [in Russian]