The Echinoid Directory

Gymnotiara Pomel, 1883, p. 101

[= Eosalenia Lambert, in Lambert & Savin, 1905, p. 311; type species Eosalenia miranda Lambert in Lambert & Savin, 1905, p. 311; ?=Endeodiadema de Loriol, 1890, p. 90, type species Endeodiadema lepidum de Lorio, 1890. ]

Diagnostic Features
  • Test rounded in profile with height about half of diameter; up to 38 mm in diameter.
  • Apical disc large, presumed monocyclic, but plates lost in all specimens.
  • Ambulacra with all elements reaching the midline. Pore-pairs in arcs of three from the ambitus adorally.
  • Primary tubercle overlapping two or three elements to form compound plates at ambitus and below; plating simple adapically.
  • Interambulacral plates carrying a single large primary tubercle; wider than tall at ambitus, but becoming taller adapically. Areoles confluent. Secondary granules confined to the adradial and interradial margins of the plate.
  • Tubercles with large boss, small perforate mamelon and distinct crenulation.
  • Peristome large with very large, U-shaped, buccal notches.
  • Spines unknown.
Jurassic (Pleinsbachian to Oxfordian) of western Europe.
Name gender feminine
Pseudodiadema varusense Cotteau, 1881, p. 231, by subsequent designation of Pawson & Fell, 1966, p. U 387.
Species Included
  • G. jessoni (Gregory, 1896, p. 465); ?Middle Jurassic (late Callovian), Upper Jurassic (Oxfordian) of France and England [= Eosalenia miranda Lambert in Lambert & Savin, 1905, p. 311]
  • G. kuhni Hess, 1971; Callovian, Switzerland.
  • G. varusense (Cotteau, 1881); Lower Jurassic (Pliensbachian) of Plan d'Aup, Var, France; Callovian of Sarthe, France.
  • G. dumortieri (Cotteau, 1881); Middle Jurassic (Bajocian) of Saint-Rambert, Ain, France.
  • G. sarthacensis Cotteau, 1856; Bathonian, France.
  • ?G. lepidum (de Loriol, 1890); Callovian, Portugal.
Classification and/or Status

Acroechinoidea, Aspidodiadematoida, Aspidodiadematidae.


Very similar in test form to the extant Plesiodiadema, differing from that taxon in having rudimentary tubercles adapically in interambulacral zones. It co-occurs with the echinoid Disaster in late Jurassic basinal mud facies, living well-below active wave base.

Distinguished from Culozoma by its narrower and taller interambulacral plating, proportionally larger interambulacral tubercles, and by its ambulacra which are never more than acrosaleniid-style in compounding (i.e. 2+1 pattern) and which have strictly uniserially arranged pore-pairs throughout.

Hess, H. 1971. Uber einige Echiniden aus Dogger und Malm des Schweizer Juras. Eclogae geologica Helvetica 64, 611-633.

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.

Vadet, A. & Slowik, D. 2001. Les oursins du Bajocien de Liocourt. Memoires de la Societe Academique du Boulonnais. Serie Histoire Naturelle 22, 1-48.