The Echinoid Directory

• Test tall and subglobular.
• Apical disc small, dicyclic. Periproct elongate with rounded posterior and angular anterior. Posterior genital plate U-shaped. Suranal plate(s) present.
• Ambulacra straight; trigeminate throughout with single primary tubercle to each plate. Plate compounding diadematid style with central element largest and all three elements reaching the perradius. Ambulacral tubercles on every triad adorally, but reduced and more irregular above the ambitus
• Pore-pairs uniserial; slightly crowded adorally to form small phyllodes.
• Interambulacral plates relatively tall. Aboral plates with a single primary tubercle positioned adradially and remainder of plate covered in irregular granulation. Adoral plates with two subequal tubercles. Primary tubercles well separated, especially aborally.
• Peristome large with deep, U-shaped buccal notches.
• Lantern and spines unknown.

Early Jurassic (Hettangian-Sinemurian), France.

Diadema globulus L. Agassiz, in Leymerie, 1838, by original designation.

• Only the type species.

Pedinoida, Pedinidae.

?Paraphyletic (by exclusion of Pseudopedina).

Differs from Pseudopedina only in having a primary tubercle to each ambulacral compound plate and in having pore-pairs uniserially arranged from the ambitus adapically. Differs from Hemipedina in being much more globular and with adapical primary tubercles more adradial in position. It is also rather more sparsely tuberculate adapically. Close to Diademopsis, but differing in having taller ambital and adapical interambulacral plates on which the primary tubercles are distinctly separated.

Lambert, J. 1900. Étude sur quelques Échinides de l\'Infra-Lias et du Lias. Bulletin de la Société des Sciences Historiques et Naturelles de l\'Yonne 52 (for 1899)(2): 3-57.

Vadet, A. 1995. Note sur les genres Diademopsis et Hemipedina. Memoires de la Societe Academique du Boulonnais 16, 89-97.