The Echinoid Directory

Lambertiaster Gauthier, 1892, p. 28

Diagnostic Features
  • Test cordiform with shallow anterior sulcus; posterior face rounded with short truncate face. Upper surface arched, lower surface weakly convex; ambitus rounded.
  • Apical disc with four gonopores; central.
  • Anterior ambulacrum gently depressed; pore-pairs differentiated, not elongate.
  • Other ambulacra petaloid aborally and weakly sunken; anterior and posterior petals subequal in length; open distally and without occluded plates.
  • Interambulacral zones keeled adapically.
  • Peristome small and pentagonal; downward-facing.
  • Labrum plate longitudinally elongate; flask-shaped; extending to fourth ambulacral plate. Sternal plates symmetric; subsequent plates alternating.  Adjacent ambulacral plates not indenting posterior interambulacrum.
  • Periproct on posterior truncate face at about mid-height. Opening framed by plates 6-8.
  • Three subanal por-pairs enlarged.
  • Peripetalous fasciole passing a few plates below the ends of the petals and branching anteriorly to form a double band.
  • Fasciole crosses plates 4 and 5 in the anterior interambulacra, plate 5 rising to 6 in the anterior column of the lateral interambulacra, passing to plate 7 in the posterior column, then passing over plates 9/10 in the posterior interambulacrum.
  • No subanal or lateroanal fasciole.
  • Aboral tuberculation fine.
Distribution
Upper Cretaceous (Campanian-Maastrichtian), North Africa.
Name gender masculine
Type
Lambertiaster douvillei Gauthier, 1892, p. 30, by original designation.
Species Included
Classification and/or Status

Spatangoida, Hemiasterina, Aeropsidae.

Monotypic.

Remarks
Differs from Periaster in having an elongate labral plate and a better developed peripetalous fasciole, which does not hug the ends of the petals, but passes several plates beneath the ends of the petal. It has a similar plastron and petal structure to Plesiaster but that taxon differs in lacking a subanal fasciole. Although Mortensen (1950) and Fischer (1966) both placed this taxon in the Palaeostomatidae, there is nothing to associate it with Palaeostoma other than its pentagonal peristome, which is seen in several other unrelated taxa also. The split anterior fasciole is reminiscent of Faorina but that genus has three gonopores and the fasciole around the anterior represents only the peripetalous fasciole, since it crosses plates 7-9 (i.e. well above the ambitus) in the anterior interambulacra. 

Overall there is a very close resemblance to Homoeaster, from which Lambertiaster differs primarily in having sunken petals.

Gauthier, V. 1892. Echinides de Tunisie. Annexe Carte geologique de Tunisie.