The Echinoid Directory

Contributed by Andrew Smith, August 2011

Glyptocyphus Pomel, 1883, p. 87

Diagnostic Features	Test depressed with ambitus at about one-third test height Apical disc small (ca. 40% test diameter), plating unknown Ambulacra straight; five elements to a compound plate throughout, the middle element occluded from the perradius. Pore-pairs more or less uniserial, arranged in weak arcs at the ambitus. A large primary tubercle straddles all five elements at the ambitus Interambulacral plates wider than tall, bearing a large primary tubercle. On the upper surface there are large wedge-shaped sutural pits on either side of the primary tubercle and secondary tuberculation is greatly reduced to a short row above the primary tubercles. On ambital and adoral plates the primary tubercle is surrounded by a U-shaped ring of secondaries. All primary tubercles are imperforate and crenulate. Peristome relatively small and obviously sunken; buccal notches feeble
Distribution	Mid Cretaceous (Albian - Cenomanian), western Europe
Name gender	masculine
Type	Cyphosoma difficilis Agassiz, in Agassiz & Desor, 1846, p. 352, by subsequent designation of Lambert & Thiery (1911, p. 219).
Species Included	Only the type species.
Classification and/or Status	Camarodonta, Glyphocyphidae or Zeuglopleuridae Monotypic.
Remarks	Very close to Rachiosoma, which differs in having less pronounced wedge-shaped notches beneath its primary aboral interambulacral tubercles. In Rachiosoma apical disc plating is monocyclic whereas in other Zeugopleuridae the apical disc is hemicyclic. It is unfortunate therefore that the apical disc plating in Glyptocyphus remains unknown. The type species was redescribed by Smith & Wright (1996). Pomel, A. 1883. Classification méthodique et genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles, 503, 131 pp. Aldolphe Jourdan, Alger. Smith, A. B. & Wright, C. W. British Cretaceous echinoids. Part 4, Stirodonta 3 (Phymosomatidae, Pseudodiadematidae) and Camarodonta. Monograph of the Palaeontographical Society, 150, 268-341, pls 93-114