The Echinoid Directory

Prosostoma Pomel, 1883, p. 55

[=Pseudasterostoma Duncan, 1889, p. 203 (objective) ]

Diagnostic Features
  • Test ovate without anterior sulcus; test with relatively flat base and domed upper surface in profile.
  • Apical disc unknown.
  • Anterior ambulacrum flush with plates slightly wider than tall; pore-pairs rudimentary.
  • Paired ambulacra petaloid; petals long (extending to ambitus), straight-sided and open distally, with wide perradial zone, but curving inwards immediately below the ambitus. Two occluded plates at ends of anterior petals.
  • Peristome close to anterior border; subelliptical and transverse; situated in a depression.
  • Plastron plating mostly obscured but labral plate relatively short compared to sternal plates (the median sternal plate suture extends along most of the visible oral surface); sternal plates fully tuberculate; no tubercles in adjacent ambulacral zones.
  • Periproct circular and not in the slightest sunken; just subambital on short posterior face.
  • Test too worn to tell whether there are fascioles or not; aboral surface without any larger primary tubercles.
Miocene, Cuba.
Name gender neuter
Asterostoma jimenoi Cotteau, 1870, p. 180; by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Spatangoida, Paleopneustina, ?Paleopneustidae.

Monotypic: ?junior synonym of Paleopneustes.


Kier (1984, p. 125) reported that the holotype had been lost and considered this taxon too little known to be determinable. In fact the type is in the collections of the Ecole de Mines in the University of Lyon (EM12132.  It is possibly a species of Paleopneustes.

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

Pomel, A. 1883. Classification méthodique et genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles, 503, 131 pp. Aldolphe Jourdan, Alger.