The Echinoid Directory

Periaster d'Orbigny, 1853, p. 269

Diagnostic Features
  • Test ovate with distinct anterior sulcus; posterior face truncate.
  • Apical disc ethmophract with four gonopores; central.
  • Anterior ambulacrum sunken from apex; pore-pairs enlarged and closely spaced adapically, presumably bearing funnel-building tube-feet
  • Paired ambulacra petaloid aborally and sunken; posterior petals shorter than anterior petals.
  • Petals with smooth, undivided perradial zone.
  • Peristome kidney-shaped and facing forward.
  • Labrum short and projecting to cover peristome in oral view; extending to second ambulacral plate. Sternal plates symmetrical with saggital median suture. Episternal plates offset.
  • Periproct on posterior truncate face.
  • Peripetalous fasciole indented at anterior, behind the anterior petals and in the posterior interambulacrum. Lateroanal fasciole present.
Upper Cretaceous (Cenomanian), Europe.
Name gender masculine
Periaster elatus, d\'Orbigny, 1853, p. 269; [Spatangus elatus Desmoulins, 1837, p. 406], by subsequent designation of Lambert 1918, p. 8.
Species Included
  • P. elatus (Desmoulins, 1837); Cenomanian, France.
  • P. undulatus (Agassiz); Cenomanian, France.
  • Numerous other species listed by Lambert & Thiery (1924) but few likely to be congeneric.
Classification and/or Status

Spatangoida, Paleopneustina, Schizasteridae.

Presumed paraphyletic.


Differs from Hemiasteridae in having deeply indented peripetalous fasciole and a short labral plate. Close to Linthia and differing only in having an ethmophract rather than ethmolytic apical disc. Presumably the most primitive schizasterid genus.

For a discussion of this genus see Neraudeau et al. 2003.

Neraudeau, D., Cronier, C. & Villier, L. 2003. The genus Periaster and the origins of the schizasterid echinoids: a short review. Pp. 87-90 in J.-P. Feral & B. David (eds) Echinoderm Research 2001. A. A. Balkema, Rotterdam.

Orbigny, A. d' 1854-60. Paléontologie Française. Terrains Crétacés. Tome 6. Echinodermes, Échinoides irréguliers. 596 pp, pls 801-1006. G. Masson, Paris. 1-32 (July 1854); 33-64 (Oct. 1854); 65-96 (Nov. 1854); 97-128 (Jan. 1855); 129-192 (Mar. 1855); 193-208 (May 1855); 209-224 (Aug. 1855); 225-272 (Nov. 1855); 273-320 (Oct. 1856) pp. 273-352 (Oct. 1856), pp. 353-384 (1857), pp. 385-400 (1858), pp. 401-432 (1858), pp. 433-596 (1860).