The Echinoid Directory

Stomopneustes Agassiz, 1841, p. 7.

Diagnostic Features
  • Test low domal, with ambitus below mid-height.
  • Apical disc small, plating firmly bound to corona; hemicyclic, with the posterior two ocular plates insert. Periproct weakly subangular. Gonopores situated towards outer point of genital plates.
  • Ambulacra complex trigeminate, with large compound plates constructed from between 3 and 5 variably sized triads, overlapped by a single large primary tubercle. Pore-pairs in oblique triads forming broad adradial bands that incorporate scattered small tubercles; pore-zones expanded adorally into well developed phyllodes.
  • Primary tubercles highly variable in size on adjacent compound plates.
  • Interambulacral plates wider than tall. A single primary tubercle centrally placed, with smaller flanking secondary tubercles on ambital and adoral plates, these approaching size of primaries on ambital plates. Little space for secondary tuberculation on ambulacral or interambulacral plates.
  • No aboral naked interradial zone.
  • Primary tubercles imperforate and non-crenulate; mamelon rather massive.
  • Peristome small, almost flush; buccal notches deep and sharp.
  • Spines short and simple; no cortex.
  • Lantern stirodont.
  • Recent, Indian Ocean.
Name gender feminine
Echinus variolaris Lamarck, 1816, p. 47, by monotypy.
Species Included
  • S. variabilis (Lamarck, 1816); Recent, Indian Ocean.
Classification and/or Status

Euechinoidea, Echinacea, Stomopneustoida, Stomopneustidae



Mortensen, T. 1935. A monograph on the Echinoidea 2. Bothriocidaroida, Melonechinoida, Lepidocentroida and Stirodonta. C. A. Reitzel, Copenhagen.

Agassiz, L. 1841. Observations sur les progress récens de l’histoire naturelle des echinoderms. Monographie d’Échinodermes vivans et fossiles. Seconde Monographie, première section, 20 pp. Petitpierre, Neuchâtel.