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Bidiastopora d'Orbigny, 1849

Photograph of Bidiastopora cervicornis. Photograph of Bidiastopora cervicornis.
Scanning electron micrograph of frond of Bidiastopora cervicornis. Scanning electron micrograph of autozooids in Bidiatopora cervicornis. Scanning electron micrograph of Bidiastopora cervicornis autozooids with apertures sealed by terminal diaphragms.

Type species

Diastopora cervicornis Michelin, 1846, p. 241
Jurassic, Bathonian, Ranville, Normandy, France

Type material: MNHN R61247 Michelin Collection

Diagnostic features

  • colony erect, bifoliate comprising bifurcating strap-like branches ('adeoniform'), twisted and often abutting older branches

  • autozooids fixed-walled, the frontal wall short and suroounded by a salient boundary wall; apertures subcircular tending to have a straight or slightly bowed proximal edge, often occluded by a terminal diaphragm

  • kenozooids may be present at sharp edges of branches, especially in axils, fixed-walled

  • gonozooids lacking in type material; in putative apparent material, they are fixed-walled, longitudinally ovate with a large, transverse ooeciopore positioned subterminally.


Order Cyclostomata
Suborder Tubulipoina
Family Multisparsidae


Bidiastopora d'Orbigny, 1849 is usually regarded as a synonym of Multisparsa d'Orbigny, 1853 as their type species - Diastopora lamellosa Michelin, 1846 and Diastopora cervicornis Michelin, 1846, respectively - are thought to be identical, for example, by Walter (1970, p. 64). Despite Bidiastopora having priority, Multisparsa has been more widely used and is the type genus of a family.


Michelin, H. 1841-1848. Iconographie zoophytologique. Bertrand, Paris, 348 pp., 79 pls.

Orbigny, A. d' 1849. A. Description de quelques genres nouveaux de Mollusques bryozoaires. Revue et Magasin de Zoologie Pure et Appliquée (2) 1, 499-504.

Walter, B. 1970. Les bryozoaires jurassiques en France. Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon 35 [for 1969], 1-328.