The Echinoid Directory

• Test depressed with rounded ambitus.
• Apical disc dicyclic; strongly dimorphic. In females strongly sunken with central spout. Smaller and standard in males. Ring of tubercles surrounding the periproct.
• Ambulacra relatively narrow, trigeminate, plate compounding echinid-style. Pore-pairs more or less uniserial to peristome. Each triad with a large primary tubercle. Double series of large sutural pits up the perradius.
• Interambulacral plates with a central primary tubercle and smaller miliaries and granules on either side. Large elongate pits on horizontal sutures to either side of the primary tubercle.
• Interradial zone deeply sunken and without tubercles in females.
• Primary tubercles imperforate and weakly crenulate.
• Peristome slightly sunken; buccal notches hardly present.

Pliocene, England, France, The Netherlands.

Temnechinus excavatus Forbes, 1852, p. 5 (=Temnopleurus woodii Agassiz, in Agassiz & Desor, 1846, p. 360), by original designation.

• Only the type species.

Euechinoidea; Camarodonta; Temnopleuroida; Temnopleuridae.

Monotypic.

Distinguished from Coptechinus, which shows a similar sexual dimorphism in its apical disc structure, by its distinctly crenulate primary tubercles, and by the presence of sunken and naked interradii in females. Distinguished from Paradoxechinus by having a single large sutural pit on each side of the primary interambulacral tubercle. Hypsiechinus has a very similar sexual dimorphism, and has crenulate tubercles, but it lacks sutural pits.

Forbes, E. 1852. Echinodermata of the British Tertiaries. Monograph of the Palaeontographical Society.

Roman, J. 1983. Echinides "Marsupiaux" (Fam. Temnopleuridae) dans le Neogene de l'Ouest Europeen. Annales de Paleontologie 69, 13-42.

Jagt, J. W. M. & Idema, J. 2002. Notes on North Sea Basin Cainozoic echinoderms. Part 2. The echinoid Temnechinus woodii (Agassiz, in Agassiz & Desor, 1846) from the Pliocene of the Netherlands. Contributions to Zoology 70, 221-227.