The Echinoid Directory

Contributed by Andrew Smith, August 2011

Pseudowashitaster Tanaka, in Takana & Kozai, 1982, p. 346

Diagnostic Features
  • Test large, ovate with anterior groove
  • Apical disc very far towards the posterior; ethmophract with 4 gonopores.
  • Ambulacrum III in sulcus aborally; wide, with uniform,  uniserially arranged pore-pairs; the two pores elongate, especially the outer, and slightly variable in width
  • Paired petals flush and strongly flexed.  The anterior petals have only rudimentary pores in the anterior column and are more than 3 times as long as the posterior petals. Posterior petals strongly divergent
  • Oral plating unknown
  • Peripetalous fasciole (?parafasciole) present
Distribution Lower Cretaceous (Barremian), Japan
Name gender masculine
Type Pseudowashitaster mysticus Takana, in Takana & Kozai, 1982, p. 348
Species Included Only the type species
Classification and/or Status

Spatangoida, Toxasteridae


Remarks In overall morphology this is very close in appearance to Heteraster but differs in having a well defined peripetalous fasciole and less heterogeneous pore-pairs in its anterior ambulacrum.  While toxasterids in general lack fascioles, partially developed bands occur in Washitaster and this taxon is better considered as a toxasterid that has independently evolved a peripetalous fasciole than as a hemiasterid convergent on Heteraster.

Takana, K. & Kozai, T. 1982. Some Cretaceous echinoids from the Monobe area, central Shikoku. Transactions and Proceedings of the Palaeontological Society of Japan 126, 341-355.