The Echinoid Directory

Radiobrissus Fourtau, 1913, p. 66

Diagnostic Features	Test ovate without anterior sulcus; posterior face truncate. Test depressed in profile. Apical disc ethmolytic with four gonopores; a little anterior of centre. Anterior ambulacrum flush, narrow; pore-pairs small and undifferentiated. Paired ambulacra petaloid; long, parallel, with narrow interporal zone; weakly depressed. Pore-pairs conjugate. In the anterior petals pore-pairs in the anterior column become rudimentary adapically. Peristome D-shaped apparently with labral plate raised to rear. Plastron plating not known for certain; fully tuberculate and apparently rather wide. Periproct on posterior truncate face. Subanal fasciole present; shield-shaped. Peripetalous fasciole narrow; not indented behind anterior petals; ambital around anterior. Aboral tuberculation coarse and heterogeneous inside peripetalous fasciole.
Distribution	Miocene (Vindobonian), Gebel Geneffe, Egypt.
Name gender	masculine
Type	Radiobrissus gneffensis Fourtau, 1913, p. 66, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida, Micrasterina, Brissidae. Monotypic; subjective junior synonym of Metalia (Eobrissus) Bell,1904
Remarks	Differs from Trachypatagus in having a shield-shaped subanal fasciole, not a bilobed one, and from Metalia by having non-confluent posterior petals. Metaliopsis has a sunken anterior ambulacrum and does not have the anterior atrophied pore-pairs in the anterior petals