The Echinoid Directory

Semipetalion Szorenyi , 1963, p. 193

Diagnostic Features
  • Test cordate with anterior sulcus; flat based and depressed in profile with low, sharp ambitus. Posterior truncated.
  • Apical disc ethmolytic, with 4 gonopores; subcentral.
  • Anterior ambulacrum sunken from apex and deepening towards ambitus; pore-pairs small, undifferentiated.
  • Anterior paired petals with pore-pairs in anterior column rudimentary adapically and only small and poorly developed distally.
  • Posterior petals bowed, with equally developed columns of conjugate pore-pairs.
  • Periproct on short posterior face.
  • Peristome wider than long; ovate; downward facing.
  • Labral plate narrow and elongate.
  • Paired sternal plates triangular and fully tuberculate.
  • Numerous coarse tubercles in all but the posterior interambulacrum. Primary tubercles sunken.
  • Subanal fasciole present.
  • Latero-oral interambulacral tubercles in rows with slightly sunken areoles.
Upper Eocene, Hungary.
Name gender neuter
Atelospatangus (Semipetalion) anomon Szorenyi, 1963, p. 195, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Spatangoida, Micrasterina, Loveniidae.



Distinguished from Nacospatangus by its four gonopores and deep anterior sulcus. Distinguished from Atelospatangus by having small but distinct petal pore-pairs towards the ends of the anterior column of the anterior paired petals.

Szorenyi, von E. 1963. Einiges uber Mitglieder der Familie Spatangidae (Echinoidea). Palaeontologische Zeitschrift, 37, 185-197, pls 14-15.