The Echinoid Directory

Isolampas Lambert, 1906, p. 33

Diagnostic Features	Test of medium size, subovate in outline, with a slightly pointed posterior extremity, low in profile, with relatively flat adoral surface, but slightly depressed towards the peristome. Apical disc subcentral; monobasal, with four gonopores. Petals moderately developed; bowed and open distally. Pore-pairs small, subconjugate; circular. The two columns of pores-pairs in each petal of slightly unequal lengths; pores beneath petals single. Peristome anterior, pentagonal, transverse, wider than high. Periproct inframarginal, transverse. Phyllodes single pored, with two series in each half ambulacrum, plus a few scattered pores in between. Bourrelets weakly developed, forming vertical-walled entrance to peristome. Buccal pores present. Tubercles the same size adorally as adapically. No naked, granular zone in interambulacrum 5.
Distribution	Middle Eocene (Lutetian) of northern Africa.
Name gender	feminine
Type	Echinolampas goujoni Pomel, 1888, p. 129; by original designation.
Species Included	Isolampas goujoni (Pomel, 1888); Lutetian, Algeria.
Classification and/or Status	Irregularia; Cassiduloida; Echinolampadidae. Subjective junior synonym of Echinolampas (Echinolampas) Gray, 1825.
Remarks	Isolampas has all the diagnostic characters of Echinolampas, with asymmetric petals (the two pore series in each petal of unequal length), an inframarginal periproct on a relatively flat adoral surface that is slightly sunken towards the peristome, and feeble bourrelets. The type species of Isolampas belongs to the subgenus E. (Echinolampas) as it has petals that are bowed (not straight), with subconjugate pores of almost equal size, the outer pores not greatly elongated transversely, and phyllodes with only two distinct series in each half-ambulacrum. Lambert & Thiery (1909-1925) use the type species of Isolampas for describing their section (subgenus) three of Echinolampas; to which they refer 18 species. P. M. Kier. 1962. Revision of the cassiduloid echinoids. Smithsonian Miscellaneous Collections, 144 (3) 262 pp. Lambert, J. 1906. Etude sur les Echinides de la Molasse de Vence. Ann. Soc. Alpes-Maritime 20, p. 38. Lambert, J. & Thiery, P. 1909-1925. Essai de nomenclature raisonnee des echinides. Libraire Septime Ferriere, Chaumont, 607 pp., 15 pls.