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.
Distribution	Late Oligocene, Australia.
Name gender	feminine
Type	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
Remarks	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.