The Echinoid Directory

Eolampas Duncan & Sladen, 1882, p. 61

Diagnostic Features
  • Test relatively small (~ 25 mm), ovate in outline, inflated, with a rounded anterior margin and slightly point posterior margin.
  • Apical system anterior, monobasal, with four gonopores.
  • Ambulacrum III non-petaloid, other ambulacra petaloid with broad petals, typically closed, with conjugate pores. Ambulacral plates beyond petals with single pores.
  • Peristome slightly anterior, transverse, oval; with vertical-walled entrance covered in fine dense tuberculation.
  • Periproct marginal to inframarginal, transverse, oval to sub triangular.
  • Bourrelets not developed.
  • Phyllodes simple, single pored, with a single series, plus one or two occluded pores in each half-ambulacrum.
  • Buccal pores present.
Distribution
  • Eocene of Pakistan and India.
Name gender feminine
Type
Eolampas antecursor Duncan & Sladen, 1882, p. 61; by monotypy.
Species Included
  • E. antecursor Duncan & Sladen, 1882; latest Palaeocene- Lower Eocene, Pakistan, India.
  • E. excentricus Duncan & Sladen, 1882; Eocene, Pakistan, India.
Classification and/or Status

Irregularia; Neognathostomata, Plesiolampadidae

Subjective junior synonym of Pseudopygaulus Coquand, 1862.

Remarks

When Duncan & Sladen erected their genus Eolampas, they were either not aware of Pseudopygaulus or did not consider it a valid genus (Kier, 1962, p. 221). They later (1887) stated that Pseudopygaulus and Eolampas are synonymous, a view held by subsequent authors. However, controversy has remained over which name has priority.

The type species of Pseudopygaulus and Eolampas are very similar and certainly congeneric. Eolampas antecursor and E. excentricus have slightly narrower petals than the type species of Pseudopygaulus (P. trigeri Coquand). Such a character is not worthy of generic distinction.

Duncan, P. M. & & Sladen, W. P. 1882. A description of the fossil Echinoidea of western Sind. The fossil Echinoidea from the Ranikot series of nummulitic strata in western Sind. Memoirs of the Geological Survey of India, Palaeontologica Indica, series 14, 1, part 3, fascicule 2, pp. 21-100, pls 5-20.

P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections 144, (3), 262 pp.