The Echinoid Directory

Contributed by Andrew Smith, April 2008

Mecaster longus (Cotteau & Gauthier, 1895, p. 40)

[=Hemiaster longus Cotteau & Gauthier, 1895]

Diagnostic Features Distinguished from typical Hemiaster by its elongate outline, its semiethmolytic apical disc, and its short, subquadrate labral plate.
Distribution Senonian, Upper Cretaceous, Iran.
Classification and/or Status A species of Mecaster
Remarks This species differs significantly from species of Hemiaster, as it has a semiethmolytic apical disc with genital plate 2 separating the posterior genital plates but not the posterior ocular plates, and has a short and subquadrate labral plate.  There is a well defined peripetalous fasciole and no sign of a latero-anal or subanal fasciole.

Cotteau, G. & Gauthier, V. 1895. Echinides fossiles. In, Mission scientifique en Perse par J. de Morgan 3. Etudes geologiques, partie II - Paleontologie. E. Leroux, Paris.