The Echinoid Directory

Contributed by Andrew Smith, August 2011

Cherreauma Vadet, Nicolleau & Pineau, 1996, p. 60

Diagnostic Features
  • Test hemispherical with flat base and domed upper surface.
  • Apical disc dicyclic without tuberculation.
  • Ambulacra narrow; plating trigeminate and pore-pairs uniserial above the ambitus and offset into triads adorally.  Pore-pairs on adapical surface obviously larger than those below the ambitus.  Adoral plating diadematoid with all three elements reaching the perradius and all overlapped by a primary tubercle.  Above the ambitus all elements equal and plate compounding acrosaleniid with a small primary tubercle overlapping two of the three elements.
  • Interambulacral plates very tall above ambitus, bearing a single primary tubercle; remainder of surface covered in fine granules.  Oral tubercles more closely spaced.
  • Presence/absence of basicoronal interambulacral plate unknown.
  • Peristome large, with obvious U-shaped buccal notches.
  • Lantern and spines unknown.
Distribution Middle Jurassic (Callovian), France.
Name gender feminine
Type Cherreauma cherreaui Vadet, Nicolleau & Pineau, 1996, p. 61, by original designation.
Species Included Only the type species.
Classification and/or Status Carinacea, Hemicidaridae, Pseudocidarinae.

Remarks The monocyclic apical disc, perforateand crenulate tubercles, and marked change in ambulacral plating and tuberculation at the ambitus all point to this being a Pseudocidarine, closely related to Pseudocidaris and Plesiocidaris.  It differes from both of these in the relatively small size and wide spacing of aboral primary interambulacral tubercles.  It looks remarkably similar to Cidaropsis michelini from the same horizon and locality, differing  in having crenulate adoral tubercles and no scrobicular rings around aboral tubercles.

Vadet, A., Nicolleau, P. & Pineau, J. P. 1996. Echinides fossiles du Callovien de la Sarthe et des confins de l'Orne. I: Les echinides reguliers. Memoires de la Societe academique du Boulonnais 17, 1-184.