Taxonomy and phylogeny of stalked crinoids (Comatulida: Bourgueticrinina) from the Upper Cretaceous of France, southern England, UK and northern Germany

The taxonomy of Cretaceous stalked crinoids of the suborder Bourgueticrinina is revised in the light of new discoveries, including the extension of rhizocrinid taxa back to the Turonian Stage. These include two new species of the genus Carstenicrinus Roux, Eléaume and Amérizane, 2019 (C. praecursor sp. nov., C. minimus sp. nov.) which display progressive modifications of columnal articulations, and Michelicrinus crenellatus gen. et sp. nov., characterized by distinctive columnal articulations and highly modified external stereom. Newly discovered arms of species generally assigned to the Upper Cretaceous genus Bourgueticrinus d’Orbigny, 1841 demonstrate the presence of both 10- and 5-armed forms; the former are placed in a new genus, Aubecrinus, type species Antedon fischeri Geinitz, 1872. The genus Dunnicrinus Moore, 1967 is shown to be a synonym of Bourgueticrinus. This genus is reviewed and it is concluded that many species, based upon cup shape, relative developments of basal and radial plates and fused columnals, are synonyms. Bourgueticrinus ellipticus forma granosus nov., occurring in the middle Santonian of the Anglo–Paris Basin, is new. Cladistic analysis of 10 species, using 25 characters, supports the monophyly of the suborder Bourgueticrinina, the family Rhizocrinidae and the genus Bourgueticrinus, but leaves an unresolved polytomy at the base of the suborder.https://zoobank.org/urn:lsid:zoobank.org:pub:E2C2783A-D147-46A2-BF16-6A13692C656E