The Echinoid Directory

Ellipsechinus Lutken, 1864, p. 165

Diagnostic Features
  • Apical disc hemicyclic with posterior oculars commonly exsert; small.
  • Test almost circular.
  • Ambulacral plating polygeminate with 6-8 pore-pairs to a compound plate, arranged in arcs in the type species; arcs separated by adradial secondary tubercles.
  • Ambulacra widened to form large phyllodes adorally.
  • One large primary tubercle to each ambulacral and interambulacral plate. Secondary tubercles flank the primary tubercle on interambulacral plates; sometimes approaching the size of the primary.
  • Buccal notches small; phyllodes developed.
  • Spines stout and pointed; usually about as long as the test diameter.
Distribution Recent, West coast of America from California to Peru.
Name gender masculine
Type Ellipsechinus macrostomus Lutken, 1864 (=Echinometra vanbrunti A. Agassiz, 1863) by original designation.
Species Included Only the type species
Classification and/or Status Camarodonta; Echinoida; Echinometridae.

Subjective junior synonym of Echinometra Gray, 1825.
Remarks Differs from the type species of Echinometra, E. lucunter only in having slightly more expanded ambulacra adorally. Mortensen (1943, p. 354) and others do not see this as justification for generic separation.

Lutken, C. F. 1864. Vid. Medd. naturh. Foren. Kbh. [1863], p. 162, 165.