The Echinoid Directory

Parapneustes Koehler, 1912, p. 164

Diagnostic Features
  • Test ovate with faint trace of anterior sulcus at ambitus; posterior face truncate.
  • Apical disc ethmolytic with three gonopores; central.
  • Anterior ambulacrum slightly sunken; pore-pairs uniserial and tube-feet not strongly developed.
  • Petals of subequal length; parallel-sided and sunken; deeply so in the females.
  • Peristome kidney-shaped, facing forward into frontal groove. Labrum projecting to cover peristome in oral view.
  • Labral plate extending to just posterior of the second ambulacral plate.
  • Periproct on posterior truncate face. Subanal tube feet scarcely penicillate.
  • Marginal fasciole present; passing two or three plates below the ends of the anterior petals. Peripetalous fasciole indented behind anterior petals and absent anteriorly. The two fascioles remain separate to the anterior interambulacrum where they may become coalesced.
Distribution Recent, Antarctic and subantarctic. 
Name gender feminine
Type Parapneustes cordatus Koehler, 1912, p. 161, by subsequent designation of Fisher, 1966, p. U598.
Species Included
  • P. cordatus (Koehler, 1912); Recent, Antarctic.
  • P. reductus (Koehler, 1812); Recent, Antarctic.
Classification and/or Status Spatangoida, Paleopneustina, incertae sedis B.
Remarks Mortensen (1951) saw no reliable distinction between this taxon and Tripylus. However, the architecture of the plastron is very different, with the type species of Tripylus having a short and wide labral plate that extends no further back than ambulacral plate 1, whereas Parapneustes has a stout, subquadrate labral plate, almost as long as the sternal plates, which extends back to the third or fourth ambulacral plate. It also differs in having marginal and peripetalous fascioles separated. It comes closest to Amphipneustes in test architecture, but is distinguished from that taxon by retaining fascioles into adulthood. De Ridder et al. (1992) provide a discussion of this genus.

Koehler, 1912. Echinodermes (Asterias, Ophiures et Echinides). Deuxieme Expedition Antarctique Francaise (1908-1910), 16, 1-270 pp., 26 pls.

Mortensen, T. 1951. A monograph of the Echinoidea V. Spatangoida 2. C. A. Reitzel, Copenhagen.

De Ridder, C., David, B., & Larrain, A. 1992. Antarctic and Subantarctic echinoids from \'Marion Dufresne\' expeditions MD03, MD04, MD08 and from the \'Polarstern\' expedition Epos III. Bulletin du Musee national d\'Histoire naturelle, Paris 4e serie 14, 405-441.