The Echinoid Directory

• Test small, depressed, domed above and flattened below; weakly pentagonal in outline.
• Apical disc small, hemicyclic (the posterior 2 ocular plates exsert); gonopores large. Genital plate 2 much larger than other genital plates.
• Ambulacra broad and straight. Pore-pairs in double column adapically becoming single at ambitus and expanding to form phyllode adorally.
• Adapical ambulacral plating consists of trigeminate element with primary tubercle alternating with two elements bound by a smaller tubercle. At ambitus plating trigeminate with ?upper element almost excluded from perradial suture and the other two elements bound by a primary tubercle the lower element being the larger. Adorally plating trigeminate with a large primary tubercle over each triad and upper and lower elements smaller.
• Interambulacra clearly zoned into upper, ambital and lower zones. The upper plates with two subequal tubercles. Towards the ambitus the primary tubercles reduce in size, the plates become much lower and more elongate and bear only small, dense, secondary tuberculation. Below the ambitus the plates become taller again and carry a row of 3 subequal primary tubercles. Primary tubercles with large mamelon and no platform; imperforate.
• Subambitally, ambulacral and interambulacral tubercles are similar in size.
• Peristome large; more than 50% test diameter.
• Spines and lantern unknown.

Lower Jurassic (Pliensbachian), Morocco.

Diplechinus hebbriensis Lambert, 1931, p. 15, by original designation.

• Only the type species.

Euechinoidea, Echinacea, Stomechinidae

Monotypic.

Lambert, J. 1937. Echinides fossiles du Maroc. Notes et Memoires du Service des mines et de la Carte geologique Maroc 39, 1-109.