The Echinoid Directory

Contributed by Andrew Smith, October 2011

Jaubertisoma jauberti Vadet, Nicolleau & Reboul, 2010 , non Cotteau, 1863

Diagnostic Features
  • Test circular, in profile flattened below and above.
  • Apical disc about one third of test diameter, usually lost; structure unknown.
  • Ambulacra polygeminate, with 5 to 7 elements to a compound plate. Compound structure unknown, but all elements seem to reach the perradial suture. Pore-pairs biserial aborally and at the ambitus, expanding into weak phyllodes adorally.
  • Ambulacral plates with a single large tubercle. Secondary tubercles forming a zig-zagged line along the perradius.
  • Interambulacral plates wider than tall, with single large primary tubercle centrally placed. Secondary tuberculation coarse and dense, covering most of the plate surface outside the areole.
  • Ambulacral and interambulacral tubercles of similar size.
  • Aboral naked interradial zone present.
  • Primary tubercles noncrenulate and perforate (some may be imperforate according to Vadet et al. 2010).
  • Peristome large, about half of test diameter, almost flush; buccal notches moderately deep and well developed.
  • Spines and lantern unknown; apparently no primordial interambulacral plate.
Distribution Middle Jurassic (Bajocian-Bathonian), Atlas Mountains, Morocco
Remarks The specimen illustrated by Vadet et al. (2010) as Jaubertisoma jauberti (Cotteau) seems to differ from Cotteau's type specimen. Their specimen has  distinctly perforate tubercles and the placement within the Phymosomatoida is doubtful.

Vadet, A., Nicolleau, P. & Reboul, R. 2010. Les Echinides de l'Atlas marocain: Bajocien Bathonien. Premiere partie: les reguliers. Annales de la Societe d'Histoire Naturelle du Boulonnais 9/1, 1-40.