The Echinoid Directory

Waurnia McNamara & Philip, 1984, p.341

Diagnostic Features
  • Test large, ovoid, with anterior notch effectively absent; rounded in profile.
  • Apical disc ethmolytic, with 4 gonopores. Positioned well anterior of centre.
  • Anterior ambulacrum very narrow and hardly sunken. Pore-pairs uniserial and small; with pores almost vertically aligned.
  • Paired petals almost flush with test; narrow and parallel-sided. Anterior pair extending to ambitus; posterior pair shorter and only extending about half-way to ambitus. Anterior paired petals set almost at 180 degrees.
  • Periproct large and longitudinally oval; on slightly undercut posterior face.
  • Peristome kidney-shaped with labral plate projecting.
  • Labral plate short and wide. Sternal plates broad and fully tuberculate. Plastron plating not known in detail.
  • No primary tubercles differentiated. Aboral tubercles apparently dense and fine.
  • Peripetalous and latero-anal fascioles developed. The peripetalous fasciole passing below the ambitus around the anterior.
Late Oligocene, Australia.
Name gender feminine
Pericosmus nelsoni McCoy, 1882, p. 17, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Spatangoida, Paleopneustina, Prenasteridae

Monotypic; junior subjective synonym of Brissomorpha  Laube, 1853


Very close to Prenaster differing only by having a larger periproct on a steeply undercut posterior face and narrower, less developed petals. Saviniaster, here treated as a junior synonym of Prenaster, also has poorly developed petals.

McNamara K. J. & Philip, G.M. 1984. A revision of the spatangoid echinoid Pericosmus from the Tertiary of Australia. Records of the Western Australia Museum 11, 319-356.