The Echinoid Directory

Contributed by Jenna Sullivan, May 2007

Echinolampas posterocrassus Gregory, 1890, p. 483

Diagnostic Features "Form a depressed, rounded pentagon: sides tumid. Apex a little behind the calycinal system; anterior slope gentle. Apical system precentral; basal pores large: those of the posterior pair the further apart. Ambulacra long, narrow: slightly petaloid but almost parallel, open below. The pore pairs of the anterior pair slightly unequal. Those of the posterior pair markedly so. Mouth anterior, in the highest part of the actinal depression; pentagonal; phyllodes very rudimentary. Anus triangular; infra-marginal." (Gregory, 1890, p. 483)
Distribution Upper Oligocene or Lower Miocene of Victoria, Southern Australia; Tasmania (Table Cap). (Roman, 1965, p. 295)
Type Holotype: Natural History Museum E3381.
Classification and/or Status Species of Echinolampas.
Remarks Differs from Echinolampas similis Agassiz, in a greater proportional breadth, and the greater inequality of the poriferous zones in each of the posterior petals. It can be easily distinguished from the other Australian species of this genus by its depressed form and the marked inequality in the length of the poriferous zones of the petaloid portions of the posterior ambulacra. Is general form reminds one of Echinolampas dispar Fritsch, from the Eocene of Borneo; from this it differs in that the mouth is more excentric in position. The anus is triangular (instead of round as in the Malaysian species), and in the latter the posterior part of the test is much wider than the anterior. (Gregory, 1890, p. 484)

Roman, J. 1965. Morphologie et Evolution des Echinolampas. Memoires du Museum National d'Histoire Naturelle. Paris. :285

Gregory, J.W. 1890b. Some Additions to th Australian Tertiary Echinoidea. Geological Magazine (dec. III) 7, 483, pl. 13, figs 4-6.