The Echinoid Directory

• Test of medium size, ovate in outline with rounded anterior and posterior margin, sometimes weakly pointed at the posterior; in profile low, flattened adapically, slightly depressed towards the peristome.
• Apical system anterior to subcentral, monobasal, with four genital pores.
• Petals narrow, subparallel and open distally, anterior three petals distinctly shorter than the posteriors in the type species, outer pores not much elongated. All ambulacral plates beyond petals single pored.
• Periproct inframarginal, longitudinal.
• Peristome transversely elongate, elliptical in outline.
• Bourrelets more or less absent, no vertical walled entrance to peristome, narrow band 2-3 milliaries deep forming ring around opening.
• Phyllodes simple, single pored, narrow, remaining similar in width towards peristome.
• Buccal pores present.
• Tubercles on adoral surface approximately the same size as on the adapical surface.

Palaeocene (Danian-Thanetian) to Lower Eocene (Ranikot) of Pakistan.

Plesiolampas elongata Duncan & Sladen, 1882, p. 10, by monotypy.

• P. elongata Duncan & Sladen, 1882; Danian, western Pakistan.
• P. ovalis Duncan & Sladen, 1882; Late Thanetian, western Pakistan.
• P. placenta Duncan & Sladen, 1882; Paleocene to Lower Eocene, Pakistan.
• P. curriae Kier, 1957; Late Paleocene, Somalia.

Irregularia; Neognathostomata; Plesiolampadidae.

Plesiolampas is similar to Echinolampas but with a longitudinal periproct and less pronounced phyllode development (Smith & Jeffery, 2000). Plesiolampas is distinguished from Oriolampas by its transversely elongate, elliptical peristome, which is distinctly subpentagonal in Oriolampas.

P. M. Duncan & W. P. Sladen. 1882. The fossil Echinoidea from the strata beneath the trap (Cardita beaumonti beds). Palaeontologica Indica, 14th series 1 (3), 1-20, pls. 1-4.

A. B. Smith & C. H. Jeffery. 2000. Maastrichtian and Palaeocene echinoids: a key to world faunas. Special Papers in Palaeontology, 63, 406 pp.