The Echinoid Directory

• Test small, moderately inflated, ovoid, greatest width posterior to centre, adoral surface flate, slightly sunken towards the peristome.
• Apical system central, compact, monobasal, with three gonopores, no gonopore in left anterior genital plate, distinct sexual dimorphism. Ocular plates very small, often separated from the central part of the apical disc.
• Ambulacra narrow, simple, nonpetaloid, with small plates and rudimentary or atrophied pores.
• Peristome anterior, circular.
• Periproct supramarginal, longitudinally oval at the end of a shallow anal sulcus.
• Phyllodes simple, with ambulacral pores enlarged adorally, uniserial, with one occluded plate in each of the posterior ambulacra adorally.
• Bourrelets poorly developed.
• Buccal pores present.
• Tubercles small, evenly distributed.
• Naked sternal zone present in interambulacrum 5.

Early to Late Eocene of Australia.

Pisolampas concinna Philip, 1963, p. 719; by original designation.

• Only the type species.

Irregularia; Cassiduloida; Neolampadidae.

Philip (1963, p. 718) reports that Pisolampas is similar to Neolampas in having only three genital pores, however, the separation of the ocular plates from the central part of the apical disc is a feature not seen in Neolampas. Pisolampas is easily distinguished from Neolampas by the position of the periproct, being supramarginal in Pisolampas and inframarginal in Neolampas.

Pisolampas is similar to Nannolampas and Tropholampas in the structure of the apical system.

G. M. Philip. 1963. Two Australian Tertiary neolampadids, and the classification of cassiduloid echinoids. Palaeontology 6 (4), pp. 718-726.