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The Echinoid Directory

Contributed by Andrew Smith, October 2010

Dubarechinus Lambert, 1937, p. 62

Diagnostic Features	Test small, spherical. Apical disc dicyclic; relatively large; lacking tubercles. Ambulacra narrow, straight, composed of simple plates from the ambitus adapically and in triads adorally, where all elements reach the perradius and two elements in each triad are overlain by a small primary tubercle. Pore-pairs small and uniserially arranged. Interambulacra composed of tall plates. Plates below the ambitus have a single small, centrally placed tubercle with surrounding granules; those at the ambitus and above have just granules. Single basicoronal interambulacral plate bordering the peristome. Primary tubercles perforate and non-crenulate. Peristome small and not sunken. Interambulacral edge to peristome strongly denticulated creating a very characteristic tridentate (triple-toothed) margin to the peristome. Spines and lantern unknown.
Distribution	Lower Jurassic (Pliensbachian), Morocco.
Name gender	masculine
Type	Dubarechinus despujolsi Lambert, 1937, p. 63. Syntypes (2): Museum National d'Histoire Naturelle, Paris J00955.
Species Included	Lambert (1937) included two species, D. despujolsi and D. termieri which differ only in size and are treated as synonyms (Vadet & Nicolleau 2005)
Classification and/or Status	Carinacea, stem group Arbacioida Monotypic.
Remarks	Distinguished by its simple ambulacral plating at the ambitus and above and by its very sparse primary tuberculation. Differs from the rather similar Gymnodiadema in having a single primary tubercle on adoral interambulacral plates rather than a row of equal-sized tubercles. Lambert, J. 1937. Echinides fossiles du Maroc. Notes et Memoires au Service des Mines et de la Carte Geologique au Maroc 39, 1-109, pls 1-4. Vadet, A. & Nicoleau, P. 2005. Les Oursins Domeriens de la region de Rich (Maroc). Annales de la Societe d'Histoire Naturelle du Boulonnais 5(1), 1-36. Smith, A.B. 2011. Gymnodiadema and the Jurassic roots of the Arbacioida (stirodont echinoids). Swiss Journal of Palaeontology 130, 155-171.