The Echinoid Directory

Eoscutum Lambert, in Lambert & Thiery, 1914, p. 293

Diagnostic Features
  • Test small, discoidal, with flat base and subconical profile. Margin sharp.
  • Apical disc central; 4 gonopores.
  • Ten straight internal radial partitions.
  • Petals moderately well developed; open distally.
  • Interambulacra remain biserial to apex.
  • Interambulacral zones about 50% width of ambulacral zones at ambitus.
  • Basicoronal circlet moderately large with interambulacral plates only a little larger than the ambulacral plates.
  • Interambulacral zones continuous on oral surface.
  • Periproct supramarginal.
  • Food grooves effectively absent.
Distribution
Lower to Middle Eocene, Europe.
Name gender neuter
Type
Porpitella donicieuxi Lambert, 1905, p. 136, by original designation.
Species Included
  • E. donicieuxi (Lambert, 1905); Lower Eocene, Aude and Herault, France
  • E. dineuri (Roman, 1989); Middle Eocene, Oise, France.
Classification and/or Status

Clypeasteroida; Scutellina; stem group scutelliforms or laganiforms.

Presumably a plesiomorphic grade.

Remarks

Roman (1990) redescribed the type species based on approximately 150 specimens. The simple radial partitions and lack of food grooves are characteristic of all small scutellines and it is not clear what distinguishes E. donicieuxi from juveniles of later taxa. Roman (1989) placed his Middle Eocene species dineuri in the genus Scutulum. This reaches 30 mm in length but retains simple radial buttressing and lacks food grooves (Scutulum at that size has complex internal butressing and food grooves). The two species included in Eoscutum may represent early stem group members of the Scutellidae.

Lambert, J. & Thiery, P. 1909-1925. Essai de Nomenclature Raisonnée des Echinides. L. Ferrière, Chaumont, fasc. 1: i-iii, 1-80, pls 1-2 (March 1909); fasc. 2: 81-160, pls 3-4 (July 1910); fasc. 3: 161-240, pls 5-6 (May 1911); fasc. 4: 241-320, pls 7-8 (March 1914); fasc. 5: 321-384, pl. 9 (Sept. 1921); fasc. 6-7: 385-512, pls 10-11, 14 (Dec. 1924); fasc. 7-8: 513-607, pls 12, 13, 15 (Feb. 1925).

Roman, J. 1989. Echinoides paleogene du bassin de Paris. Apercus nouveaux. Actes de la 114e Congress national de la Societe sav. Paris, Section des sciences geologiques du Bassin parisien 293-304.

Roman, J. 1990. L`àncetre eocene des Scutellidae (Echinoidea; Clypeasteroida). Pp. 41-47 in C. de Ridder et al. (eds) Echinoderm Research. Proceedings of the Second European Conference on Echinoderms, Brussels. A. A. Balkem, Rotterdam.