The Echinoid Directory

Apoxypetalum McNamara, 1993, p. 40

Diagnostic Features	Test ovate with shallow anterior sulcus at ambitus. Depressed in profile with sunken apical marsupium in females (male illustrated here). Apical disc ethmolytic with four gonopores; plate G2 projects behind posterior oculars. Apical disc anterior of centre. Anterior ambulacrum very slightly depressed aborally; with simple pore-pairs. Petals short and rather broadly depressed; cruciform; anterior petals with anterior column of pore-pairs becoming rudimentary adapically; other pore-pairs circumflexed and conjugate. Peristome D-shaped, without projecting labrum; closer to centre than anterior. Labral plate short, about as long as wide; extending to second ambulacral plate. Plastron triangular, expanding posteriorly, with sagittal keel. Periproct at top of short posterior truncate face. Bilobed subanal fasciole and narrow peripetalous fasciole present; not indented interradially. Larger tubercles present only adjacent to the adapical portion of the frontal ambulacrum and immediately in front of the anterior pair of petals.
Distribution	Upper Oligocene of Australia.
Name gender	neuter
Type	Apoxypetalum chenjafra McNamara, 1993, p. 40, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida, Micrasterina, unnamed family. Monotypic; subjective junior synonym of Brissopatagus Cotteau, 1863.
Remarks	Differs from Brissopatagus Cotteau in having shorter and slightly less sunken petals but is otherwise very similar. McNamara, K. J. 1993. A new genus of brissid echinoid from the Upper Oligocene of Victoria. Proceedings of the Royal Society of Victoria 105, 39-48.