The Echinoid Directory

• Test ovate without anterior sulcus.
• Apical disc ethmolytic, with 4 gonopores. Madreporic plate projecting to the posterior of the posterior ocular plates.
• Anterior ambulacrum narrow and flush; pore-pairs small, simple isopores.
• Other ambulacra petaloid and depressed, the anterior pair almost at 180 degrees. Petals sunken and straight-sided; closed distally; no occluded plates at tip.
• Periproct large; inframarginal with well developed apical hood; opening taller than wide.
• Peristome wider than long; kidney-shaped and overarched by labrum.
• Labral plate short and wide; not extending beyond first ambulacral plate. Sternal plates large and densely tuberculate; plastron strongly bowed.
• No large primary tubercles differentiated aborally.
• Tuberculation abraded so that fasciole arrangement unknown.

Miocene, Cuba.

Hernandezaster hernandezi Sanchez Roig, 1949, p. 212, by original designation.

Only the type species.

Spatangoida, Micrasterina, Brissidae.

Monotypic: subjective junior synonym of Meoma Gray, 1851.

Only a single specimen exists of this species and genus, and this has been redescribed by Kier (1984). The specimen is too worn to tell what fascioles are present, but the plastron structure, apical disc and petal arrangement are all consistent with this being a brissid, as Kier suspected. It is very close to Meoma in petal shape and periproct position and differs only by its complete lack of a frontal groove.

It differs from Brissus in having its periproct inframarginal, on the steeply undercut posterior face and the anterior petals more strongly angled. Brissomorpha has a similar hood projecting over its periproctal opening, but differs in having its petals more or less flush and in lacking a lateroanal fasciole.

Kier, P.M. 1984. Fossil spatangoid echinoids of Cuba. Smithsonian Contributions to Paleobiology 55, 1-336.