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Clavicavea d'Orbigny, 1853

D'Orbigny's illustration of Clavicavea regularis. Scanning electron micrograph of Clavicavea regularis. Scanni ng electron micrograph of small colony of Clavicavea regularis. Scanning electron micrograph showing base of a Clavicavea regularis colony.
Scanning electron micrograph of branch surface of Clavicavea regularis. Scanning electron micrograph of Clavicavea regularis showing autozooidal apertures and cancelli. Scanning electron micrograph showing encrusting base of Clavicavea regularis. Scanning electron micrograph of distal branch of Clavicavea regularis.

Type species

Clavicavea regularis d'Orbigny, 1853, p. 941
Cretaceous, Senonian, Luines and Saintes, France

Syntypes: MNHN d'Orbigny Collection 8345 (2 specimens)

Diagnostic features

  • colony erect, dendroid, narrow-branched, branch diameter increasing modestly in a distal direction from a slightly expanded base which is covered by kenozooids; both syntypes comprise single, non-bifurcating branches

  • autozooids free-walled, arranged in well-defined longitudinal rows separated by rounded ridges; aperture subcircular with a slight rim

  • kenozooids of the cancelli-type, covering the entire base and most proximal part of the erect branch, and arranged in two series between the longitudinal ridges defining the autozooidal rows, about 10 cancelli per autozooid

  • gonozooid absent


Order Cyclostomata
Suborder Cancellata
Family Petaloporidae


Both syntypes are juvenile colonies and almost certainly assignable to Petalopora, P. costata (d'Orbigny, 1851) according to Gregory (1899, p. 377). The genus Clavicavea is therefore considered to be a synonym of Petalopora.

One of the syntypes is free of its substrate but the other encrusts an echinodern ossicle.


Gregory, J.W. 1899. Catalogue of the Fossil Bryozoa in the Department of Geology, British Museum (Natural History). The Cretaceous Bryozoa. Volume 1. BM (NH), London, 457 pp.

Orbigny, A. d' 1851-1854. Paléontologie Française, Terrains Crétacé, 5, Bryozoaires. Masson, Paris, 1192 pp, pls 600-800.