The Echinoid Directory

Contributed by Jenna Sullivan, May 2007

Echinolampas jacquemonti d'Archiac and Haime, 1853, p. 211

Diagnostic Features "Test of moderate size. Apical disc eccentric in front and corresponds with the apical summit of the test, distant from the anterior extremity a little less tan two fifths of the length. Lateral margins are thick, tumid, and well-rouded on to the actinal surface, which also has a tumid characterin consequence of the slight but distinct depression arond the peristome. Apical disc small, with four genital pores, which are of comparatively large size and occupy nearly the whole of their plate; the anterior pair are rather closer together than the posterior pair. Whole central portion occupied by madreporiform body, the punctures of which are very small and numerous; the surface is often distinctly convex, and minute miliary granules are distributed irregularly over it. Ambulacral petals comparatively small, narrow, expanding rather rapidly for a short distance from the apex and then gradually contracting.Lateral interradial areas are broadest, nearly equal to the whole area included by the antero-lateral ambulacra. Peristome is rather large, distinctly pentagonal, with the transverse diameter rather greater than the longitudinal. Periproct is small, transverse, with an outline varying between suboval and subtriangular, placed close to th emargin on the slight rounding which unites the actinal surface with the ambitus, and immediately below the posterior rostration." (Duncan and Sladen, 1884, p. 332)
Distribution Lower Miocene of Kutch, Pakistan; Pengu Stage, Lower Miocene of Myanmar; Lower and Middle Fars series, Helvetian and Tortonian of Iraq; Inferior Miocene (?) of Somalia; Burdigalian of Zululand, South Africa; Santiago Formation, Lower Miocene of Mozambique; Miocene of Taiwan. (Roman, 1965, p. 285)
Type Holotype: Natural History Museum E78558.
Classification and/or Status Species of Echinolampas
Remarks Closely allied with Echinolampas indica, from the Miocene of Katchh, however, the test of E. indica is habitually higher, more regularly convex abactinally, and more tumid laterally. The inequality of the porifeous zones and the amount of their curvature is greater. The eccentricity of the apical disc is less, the proportions of the peristomial and periproctal apertures, as well as their form, are different. (Duncan and Sladen, 1884, p. 336)

Archiac, E. J. A. D. de St. S., le Vicompte d' and Haime, J. 1853. Description des Animaux Fossiles du Groupe Nummulitique de l'Inde, Paris, p. 211, pl. 14, fig. 5a, b.

Duncan, P.M. and Sladen, W. P. 1885. Tertiary and Upper Cretaceous Fossils of Western Sind. The fossil Echinoidea from the Gaj or Miocene Series . Memoirs of the Geological Survey of India Palaeontologica Indica 14(1): part 3, fascicule 5, 273-368, pls 44-55.

Roman, J. 1965. Morphologie et Evolution des Echinolampas. Memoires du Museum National d'Histoire Naturelle. Paris. :285