The Echinoid Directory

• Test depressed to subglobular; up to 15 mm in diameter.
• Apical disc large, presumed monocyclic, but plates lost in all specimens.
• Ambulacra with all elements reaching the midline and of similar size; no obvious grouping into triads.
• Ambulacral tuberculation rather irregular but tending to have primary tubercle on every third plate, sometimes every second plate. Primary tubercles confined to a single element.
• Interambulacral plates only slightly wider than tall, carrying a single large primary tubercle. Adapical plates with rudimentary tubercles only. Secondary granules confined to the outer corners of the plate.
• Tubercles with large boss, small perforate mamelon and distinct crenulation.
• Peristome with U-shaped buccal notches.
• Spines unknown.

Middle Jurassic (Bajocian) to Upper Jurassic (Oxfordian).

Eosalenia miranda Lambert, in Lambert & Savin, 1905, p. 311, by monotypy [=Pseudodiadema jessoni Gregory, 1896, p. 465].

• E. 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].
• Eosalenia sp. Vadet & Nicolleau, 2002 [as E. miranda]; Upper Bajocian, France.

Acroechinoidea, Aspidodiadematoida, Aspidodiadematidae.

Subjective junior synonym of Gymnotiara Pomel, 1883.

Aspidodiadema differs in having a large primary tubercle overlapping three ambulacral elements at the ambitus. Culozoma is very similar, but has ambulacral pore-pairs distinctly offset into triads at the ambitus and forming well developed phyllodes adorally. It also has fully formed primary tubercles on adapical interambulacral plates.

Lambert, J. in Savin, L. 1905. Revision des Échinides fossiles du Département de l’Isère. Bulletin de la Société de Statistique des Sciences naturelles et des Arts industriels du Département de l’Isère, (4) 8, 109-315.

Smith, A.B. 1995. Echinoids from the Jurassic Oxford Clay of England. Palaeontology 38. 743-755.

Vadet, A. & Nicolleau, P. 2002. Decouverte d'Eosalenia miranda dans le Bajocien superieur de Misere Chavagne. Annales de la Societe d\'Histoire Naturelle du Boulonnais 2(1); 1-3.