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Bimulticavea d'Orbigny, 1853


D'Orbigny's illustrations of Bimulticavea variabilis Low magnification scanning electron micrograph of the lectotype colony of Bimulticavea variabilis. Scanning electron micrograph of a maculum in Bimulticavea variabilis.
Scanning electron micrograph of kenozooids from the centre of a maculum of Bimulticavea variabilis. Scanning electron micrograph of Bimulticavea variabilis showing two fascicles and the depression bewteen. Scanning electron micrograph of autozooids and kenozooids in Bimulticavea varaibilis.

Type species

Bimulticavea variabilis d'Orbigny, 1853, p. 982
Cretaceous, 'Senonian', Meudon, France

Type material: MNHN R61820, d'Orbigny Collection (ex 8370) (8 pieces, including the lectotype (Buge 1975, p. 19), Voigt Photocard 5940)


Diagnostic features

  • colony multilamellar, the incomplete lectotype colony free-growing with an undulose basal exterior wall on the underside; maculate; zooidal walls often produced into low spines where three walls meet

  • autozooids free-walled, their elliptical apertures slightly salient and either aggregated into about 8 poorly-defined fascicles radiating from centres of maculae, or interspersed among kenozooids in intermacular regions; some apertures sealed by diaphragms

  • kenozooids free-walled with funnel-like, depressed polygonal apertures which are large at the centres of maculae but about the same diameter as those of autozooids in intermacular regions; some apertures sealed by complete or partial, iris-like diaphragms

  • gonozooid unknown


Classification

Order Cyclostomata
?Suborder Rectangulata
?Family Disporellidae


Remarks

This genus has generally been accepted as a 'lichenoporid', i.e. belonging to the cyclostome suborder Rectangulata. However, its affinities must remain in doubt in the absence of gonozooids which are not developed in either d'Orbigny's material or in the specimens described by Buge (1975). Buge regarded B. variabilis as belonging to Lichenopora but this Cretaceous-Miocene genus as now understood has tiny cone-shaped colonies (Gordon & Taylor 1997) quite unlike B. variabilis in form. Bimulticavea may, however, be related to the rectangulate genera Disporella and Patinella, or to the cerioporine genus Favosipora (see Gordon & Taylor 2001), depending on whether the gonozooid has a roof of interior or exterior wall respectively.


References

Buge, E. 1975. Présence de Lichenopora variabilis (d'Orbigny) (Bryozoa-Cyclostomata) dans le Campanian supérieur du bassin d'Aquitaine. Bulletin du Muséum National d'Histoire Naturelle, Sciences de la Terre 42: 17-28.

Gordon, D. P. & Taylor, P. D. 1997. The Cretaceous-Miocene genus Lichenopora (Bryozoa), with a description of a new species from New Zealand. Bulletin of The Natural History Museum, London, Geology Series 53: 71-78.

Gordon, D.P. & Taylor, P.D. 2001. New Zealand Recent Densiporidae and Lichenoporidae (Bryozoa: Cyclostomata). Species Diversity 6: 243-290.

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