Microcrinoids (Echinodermata, Articulata, Roveacrinida) from the Cenomanian-Santonian chalk of the Anglo-Paris Basin: taxonomy and biostratigraphy
Gale, Andrew Scott
Revue de Paléobiologie
Pelagic microcrinoids of the suborder Roveacrinida (families Roveacrinidae and Saccocomidae) from the Cenomanian, Turonian, Coniacian and Santonian chalks of the Anglo-Paris Basin are revised taxonomically, and their stratigraphical distribution is used as the basis for a new zonation. The Saccocomidae includes two subfamilies, the Saccocominae and Applinocrinae. New Saccocominae described include the first Cretaceous records of the predominantly Jurassic genus Crassicoma, C. cretaceus sp. nov. and C. veulesensis sp. nov. (Turonian and Santonian, respectively) and Santonian species of Costatocrinus, C. erismus sp. nov., C. elegans sp. nov., C. rostratus sp. nov., forma latus nov. and forma angustus nov. The Turonian genus Roveacrinoides is transferred from the Roveacrinidae to the Saccocominae. Applinocrininae represented include the genera Applinocrinus and Sagittacrinus, and A. striatus sp. nov., S. tricostatus sp. nov. and S. transiens sp. nov. are described from the Santonian. The Roveacrinidae are represented by three subfamilies, the Roveacrininae, Orthogonocrininae nov. and Hessicrininae. The genus Roveacrinus is subdivided, with the resurrection of Drepanocrinus Jaekel, 1918, and description of Caveacrinus gen. nov., Dentatocrinus gen. nov. and Euglyphocrinus gen. nov. Drepanocrinus includes new species and formae from the Turonian and Coniacian, including D. marocensis sp. nov., D. westphalicus forma digitatus nov., D. westphalicus forma meadsensis nov., D. striatulus sp. nov., D. striatulus forma cuspidatus nov., D. striatulus forma pentapodus nov., D. striatulus forma conicus nov. and D. communis forma dubrisiensis nov. Roveacrinus labyrinthus sp. nov., R. falcifer sp. nov., R. bifidus sp. nov. and R. ferrei sp. nov. are described from the Cenomanian and Turonian. Caveacrinus gen. nov. contains two species, C. asymmetricus sp. nov. and C. serratus sp. nov., and Dentatocrinus gen. nov. has four: D. dentatus sp. nov., D. minutus sp. nov., D. compactus sp. nov. and D. hoyezi sp. nov. Both genera are of Turonian age. The Orthogonocrininae nov. includes the genera Orthogonocrinus, Hyalocrinus, Styracocrinus, Discocrinus and Lebenharticrinus. A new species of Orthogonocrinus, O. cantabrigensis sp. nov., is described from the Cenomanian, and two species of Lebenharticrinus from the Turonian (L. incisurus sp. nov., L. ultimus sp. nov.). Turonian and Coniacian (L. incisurus sp. nov.) and Santonian (L. ultimus sp. nov.). New Hessicrininae include species of Hessicrinus (H. robustus sp. nov., H. thoracifer sp. nov., H. primus sp. nov. of Turonian and Coniacian age), and Roveacrinus bairstowi Peck, 1955 is transferred to Hessicrinus. Lucernacrinus oculus sp. nov., Stellacrinus delicatus sp. nov. and S. angelicus sp. nov. are described from the Santonian, and S. stapes sp. nov. from the Coniacian. The detailed stratigraphical distribution of the species is used as a basis for the erection of roveacrinid zones for the uppermost Cenomanian, Turonian, Coniacian and Santonian. Lastly, the Cretaceous history of the Roveacrinida is reviewed in the light of the new material.