The Echinoid Directory

Linopneustes A. Agassiz, 1881, p. 167

Diagnostic Features
  • Test ovate with shallow but distinct anterior sulcus; upper surface domed, lower surface approximately flat. Plating thin.
  • Apical disc ethmolytic with four gonopores; central; gonopores situated on interior part of plates.
  • Anterior ambulacrum flush adapically, but becoming weakly sunken towards the ambitus. Pore-pairs small and vertical.
  • Paired ambulacra petaloid; petals extending most of the way to the ambitus; open, parallel-sided, without occluded plates at ends.
  • Peristome D-shaped and clearly visible in oral view; not strongly sunken. Phyllodes not strongly developed.
  • Plastron plating: Labral plate elongate and wedge-like, extending to third ambulacral plate. Sternal plates short and triangular. Episternal plates symmetric and paired; strongly indented by ambulacral plate 6 to rear.
  • Periproct at rear; just inframarginal. Oral side framed by interambulacral plates 5a/b.
  • Thin peripetalous fasciole present running around margin. Subanal fasciole present but often obliterated in adults. Three enlarged ambulacral plates indenting the posterior interambulacrum behind the episternals (plates 6-8).
  • No tubercles on posterior ambulacra on oral surface.
Recent, Caribbean and West Pacific.
Name gender feminine
Palaeopneustes murrayi A. Agassiz, 1873, p 168, by original designation.
Species Included
  • L. murrayi (Agassiz, 1879): Recent, West Pacific.
  • L. fragilis (de Meijere, 1902); Recent, West Pacific.
  • L. spectabilis (de Meijere, 1902); Recent, West Pacific.
  • L. longispinus (Agassiz); Recent, Caribbean.
  • L. brachypetalus Mortensen, 1950; Recent, Australia.
  • L. excentricus de Meijere, 1902; Recent, West Pacific.
Classification and/or Status

Spatangoida, Micrasterina, unnamed taxon 2.



Very close to Elipneustes in form, but with the sternal plate a little shorter than in that taxon, narrower and straighter petals and a more obvious frontal sulcus. Also close to Mazettia but that taxon has petals that converge and close distally, and do not reach the ambitus.

Agassiz, A. 1881. Report on the scientific results of the voyage of the H.M.S. "Challenger" during the years 1873-1876, Zoology, Vol. III, Part IX, Report on the Echinoidea. Longmans & Company, London, 321 pp.

Mortensen, T. 1950. A Monograph of the Echinoidea, Spatangoidea I. C. A. Reitzel, Copenhagen.