The Echinoid Directory

Heterolampas Cotteau, 1862 p. 198 (72)

Diagnostic Features
  • Test subcircular in outline without anterior sulcus; posterior face truncate. Test depressed in profile with steeply rounded sides.
  • Apical disc ethmophract with four gonopores; the madreporic plate separates the posterior two genital plates; central.
  • Ambulacra all similar; all five ambulacra petaloid aborally and weakly sunken; the pore-pairs in ambulacrum III only a little narrower than those in other ambulacra.
  • Petals long and parallel-sided; open distally, with rather narrow interporal zone; no occluded plates at ends of petals.
  • Peristome ovate and subcentral; phyllode pores double and well-developed.
  • Labral plate triangular; extending to fifth ambulacral plate. Sternal plates large, triangular and symmetrical, with vertical median suture; forming most of plastron. Episternal plates biserially offset at rear; not indented by adjacent ambulacral plates.
  • Periproct on posterior truncate face.
  • Narrow peripetalous fasciole present, passing immediately around the ends of the petals. Not indented interradially. No other fascioles.
  • Aboral tuberculation comprises rather coarse tubercles set amongst small granules.
Distribution
Upper Cretaceous (Campanian), North Africa.
Name gender feminine
Type
Heterolampas maresi Cotteau, 1862, p. 199, by original designation.
Species Included
  • Only the type species.
Classification and/or Status

Spatangoida, Hemiasterina, Hemiasteridae.

Monotypic; possibly primitive sister taxon to the Asterostomatidae.

Remarks

Differs from Hemiaster in having long, equal petals and coarse aboral tuberculation. Differs from Mecaster in having petals and frontal ambulacrum only feebly depressed aborally and in having a primitive plastron arrangement. No other hemiasterid has a labral plate that extends as far to the rear as ambulacral plate 5.

The large number of ambulacral plates that adjoin the sternal plates suggests that this taxon may be antecedent to the Tertiary Asterostomatidae.

Cottesu, G. 1862. Echinides nouveaux ou peu connus. Revue et Magazine de Zoologie (2) 14, p. 198.