The Echinoid Directory

Moiropsis A. Agassiz, 1881, p. 205

Diagnostic Features
  • Test ovate with anterior sulcus; base slightly pointed; inflated in profile.
  • Apical disc ethmolytic, with 2 gonopores, the anterior gonopores missing; posterior genital plates widely separated.
  • Anterior ambulacrum deeply sunken adapically but shallowing by ambitus. Pore-pairs and tube-feet specialized; arranged uniserially. Sunken part not as long as the anterior petals.
  • Other ambulacra also deeply sunken, forming slit-like depressions on aboral surface.
  • Periproct small and marginal, on concave truncate face. Subanal region projecting slightly.
  • Peristome large; wider than long; kidney-shaped.
  • Labral plate short and wide; in broad contact with sternal plates; extending to first ambulacral plate only.
  • Aboral tuberculation fine, uniform and dense; oral tubercles also dense and uniform.
  • Well-developed peripetalous and lateral fascioles, the peripetalous fasciole following the petals closely.
Distribution
Miocene to Recent, West Pacific.
Name gender feminine
Type
Schizaster claudicans A. Agassiz, 1879, p. 21; by original designation.
Species Included
  • M. depressa Hayasaka, 1948; Miocene, Taiwan.
  • M. claudicans Agassiz, 1879; Recent, Kei Islands.
Classification and/or Status

Spatangoida, Paleopneustina, Schizasteridae.

Monophyletic.

Remarks

Easily recognized by its narrow slit-like ambulacral petals and frontal groove, and its two gonopores. It differs from the closely related Moira only in having the sunken zone of the frontal ambulacrum short and ending behind the anterior petals.

Agassiz, A. 1881. Report on the Echinoidea, dredged by H.M.S. Challenger during the years 1873-1876. - pp. 1-321, pls 1-45

Mortensen, T. 1951. A monograph of the Echinoidea. V. Spatangoida 2. C. A. Reitzel, Copenhagen