The Echinoid Directory

Contributed by Jenna Sullivan, May 2007

Conoclypus L. Agassiz, 1839, p. 61

[= Oviclypeus Dames, 1878, p. 44 (subjective) ]

Diagnostic Features
  • Large forms with thick test; aboral side conical; lower surface flat and sunken towards peristome.
  • Apical system central or slightly anterior; monobasal; four genital pores, no genital 5; madreporite strongly developed.
  • Ambulacra petaloid aborally, with broad poriferous zones, not, or at most slightly, converging towards the edge of the test. The pores are wide apart, conjugate; the inner pore is small, circular, the outer more or less elongate.
  • On the oral side the pores continue in a single series to the peristome. No true phyllodes, but "pseudophyllodes". The ambulacral plates are simple, only in the pseudo-phyllodes here and there a demi-plate may be found.
  • Adorally the interambulacra form conspicuous bourrelets.
  • Periproct inframarginal, longitudinally oval.
  • Peristome central, more or less transversely elongate; there are no buccal notches.
  • A well developed dental apparatus, with corresponding auricles.
  • Primary tubercles small, but scrobiculate, perforate, and crenulate; they do not show any arrangement in vertical series.
Distribution Eocene of circum-mediterranean countries, India and Madagascar (?Brazil); Miocene of Italy. (Mortensen, 1948, p. 352)
Name gender masculine
Type Clypeus conoideus Leske, 1778, p. 159, by subsequent designation of Lambert & Thiery, 1914, p. 286.
Species Included
  • C. conoideus (Leske, 1778); Middle Eocene, Europe
  • C. pilgrimi Davies, 1927; Lower Eocene, Pakistan
  • C. pinfoldi Gill, 1953; Lower Eocene, Pakistan
  • C. lorioli (Dames, 1877); Eocene, Italy & Slovenia
The following are indeterminate or wrongly assigned:
Conoclypus pulvinatus Sowerb, 1840 = indeterminate.
Classification and/or Status Irregularia; stem group Clypeasteroida; Conoclypidae.
Remarks Differs from Heteroclypeus in that the periproct is elongate, in contradistinction to the transverse oval periproct of Heteroclypeus. (Mortensen, 1948, p. 352).

Agassiz, L. 1839. Description des Échinodermes fossiles de la Suisse. Première partie, Spatangoides et Clypéasteroides. Mémoires de la Société helvétique des Sciences naturelles, 3, i-viii + 1-101, 14 pls.

Mortensen, T.H. 1948. A Monograph of the Echinoidea. IV.1 Cassiduloida and Holectypoida. C.A. Reitzel, Copenhagen. 4(1):350