A review of the biogeography of cretaceous belemnites

Abstract

A pattern of Boreal and Tethyan marine faunal realms was initiated in the Jurassic and continued into the Cretaceous. The belemnites first display this pattern in the Early Jurassic, and from the Middle Jurassic to earliest Cretaceous two morphologically distinct suborders, the Belemnitina and the Belemnopseina, were restricted to the boreal shelf seas and the Tethyan and Gondwanan shelf seas, respectively. An Austral marine realm was notably lacking during this interval. Significant change occurred in the late Barremian to early Aptian when the Belemnitina died out leaving the Belemnopseina, initially the Belemnopseidae, but followed by the Belemnitellidae, to invade their niches. An Austral Realm was initiated at this time, with the first appearance of a Gondwanan belemnopseine family, the Dimitobelidae. The Tethyan belemnite realm cannot be recognised after the Cenomanian, although the Belemnitellidae and Dimitobelidae defined Boreal and Austral belemnite realms throughout the Late Cretaceous. Climatic zonation remains the most often cited prime cause of provinciality in belemnites. However, examination of diversity patterns and faunal distributions reveals that palaeogeographic and palaeoceanographic factors were as important, if not more so, in determining Cretaceous provincial boundaries.