The Echinoid Directory

Protobrissus Lambert, 1907, p. 719

Diagnostic Features	Test small, elongate with faint anterior sulcus; depressed above and below. Apical disc anterior of centre; tetrabasal and ethmolytic; genital plate 2 slender but not projecting far to the rear. Ambulacrum III flush adapically but weakly depressed by ambitus. Pore-pairs not seen so presumably small adapically. Paired ambulacra petaloid and weakly depressed. The anterior pair widely divergent and slightly shorter than the posterior pair. Pore-pairs elongate with perradial zone about same width as a pore-pair. No occluded plates at end. Phyllodes short. Peristome ovate and downward facing. Labrum extending to second ambulacral plate; slightly longer than wide. Sternal plates paired and episternal plates probably opposite, although this part of the test badly abraided. Periproct large and on short truncate posterior face. Tuberculation heterogeneous aborally, with mixed tubercles and granules. Marginal fasciole present but not well developed.
Distribution	Lower Palaeocene (Garrumnian); Ariege, French Pyrenees.
Name gender	masculine
Type	Protobrissus mortenseni, Lambert, 1907 p. 719, by original designation.
Species Included	Four other species are listed by Poslavskaia & Moskvin (1960), which are better known. However, there is no certainty that they are congeneric with Lambert's species.
Classification and/or Status	Spatangoida, Micrasterina, family uncertain. Monotypic, Incertae sedis.
Remarks	Based on an individual 15 mm in length that may be a juvenile (the periproct is supramarginal). Lambert, J. 1907. Note due quelques echinides de la Haute-Garonne. Bulletine de la Societe geologique de France, serie 4 6, p. 719, pl. 25, figs 17-20.