The Echinoid Directory

Leptechinus Gauthier, 1889, p. 107

[=Peronia Duncan, 1889, p. 82 (objective); =Prototiara Lambert, 1900, p. 34, type species Pleurodiadema jutieri Cotteau, 1883 ]

Diagnostic Features
  • Test small, subglobular.
  • Apical disc relatively large; monocyclic, with narrow ring of ocular and genital plates and large subpentagonal periproct with smooth margins.
  • Ambulacra straight, narrow; composed entirely of simple elements. Pore-pairs oblique and uniserially arranged throughout.
  • Perradial portion of ambulacral plate of same width as the pore zone; each plate with a small cluster of granules and every third element having a small but recognisable tubercle.
  • Interambulacral plates relatively tall, each with a rather large primary tubercle; tubercles non-crenulate and with a rather large imperforate mamelon. Areoles circular, weakly incised and separated by granules in each column. The remainder of the plate is covered in rather dense and somewhat heterogeneous granules and fine secondary tuberculation.
  • Peristome a little over 50% test diameter and flush; buccal notches very shallow and weakly defined but present.
  • Spines and lantern unknown.
Distribution Lower Jurassic (Pliensbachian) to Lower Cretaceous (Neocomian); North Africa.
Name gender masculine
Type Cyphosoma heinzi Peron & Gauthier, 1884, p. 96, by original designation.
Species Included
  • L. heinzi (Peron & Gauthier, 1884); Neocomian, Algeria.
  • L. jutieri (Cotteau, 1883); Upper Pliensbachian, France.
  • L. loryi (Lambert, 1910); Bathonian, France.
  • L. mestreae (Lambert, 1922); Bajocian, Spain.
Classification and/or Status Euechinoidea, Carinacea, ?Echinacea incertae sedis
Remarks The peculiar mixture of characters reported for this taxon leave it difficult to place. Its simple ambulacra with their cluster of granules, monocyclic apical disc and the imperforate primary tubercles make this an altogether singular taxon. It differs from Pleurodiadema in having a monocyclic apical disc and in having entirely simple ambulacral plating. 

Cotteau, G., Peron, P. A. & Gauthier, V. 1884. Echinides fossiles de l\'Algerie. 2. Etages tithonique & Neocomien. G. Masson, Paris, 99 pp., 9 pls.

Gauthier, V. 1889. Description des échinides fossiles recueillis en 1885 et 1886 dans la région sud des hautes-plateaux de la Tunisie, par M. Philippe Thomas. Exploration scientifique de la Tunisie, Géologie, Paléontologie, 116 pp., 32 pls. Imprimerie Nationale, Paris.