The Echinoid Directory

Miotoxaster Pomel, 1883, p. 44

Diagnostic Features
  • Test cordiform with shallow but distinct anterior sulcus; posterior face obliquely truncate. Ambitus rounded.
  • Apical disc ethmophract with four gonopores (genital plate 2 separates the posterior genital plates but not the posterior ocular plates; central.
  • Ambulacrum III weakly sunken from apex to peristome; pore-pairs small and circumflexed, very different from those in the paired petals.
  • Paired ambulacra petaloid; petals flush, the anterior pair flexed and about twice as long as the posterior pair; open distally. Both pore-pairs slit-like. Petaloid zones ending gradually.
  • Peristome small, subcircular and downward-facing.
  • Labrum long, triangular, with handle extending to plate 5.a.2; extending to ambulacral plate 3. Sternal plates subequal in size but with oblique suture. Episternal plates offset.
  • Periproct small and rounded, towards the top of posterior truncate face.
  • No fasicoles.
  • Aboral surface with small scattered tubercles set in a groundmass of granules.
Lower Cretaceous (Hauterivian to Aptian, ?Albian); Europe.
Name gender masculine
Echinospatagus breyniusi d'Orbigny, 1859, p. 173, by original designation.
Species Included
  • M. breyniusi (d'Orbigny, 1859); Aptian, France.
  • M. seyneusis (Lambert, 1920); Barremian, France.
  • M. trigonalis (Desor 1847); Albian, France.
  • Others not checked....
Classification and/or Status

Spatangoida, stem group (toxasterids).

Subjective junior synonym of Epiaster d'Orbigny, 1853.

Differs from Toxaster in having a genital plate 2 separating the posterior genital plates in the apical disc, and pore-pairs in the anterior ambulacrum that are differentiated from those in the paired ambulacra. Differs from Pliotoxaster in having the paired ambulacra flush, not sunken.

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.