Crinoids from the Shenley Limestone (Albian) of Leighton Buzzard, Bedfordshire, UK

摘要

A diverse and exceptionally preserved crinoid fauna is described from the Early Albian (Leymeriella tardefurcata Zone) Shenley Limestone of Leighton Buzzard (Bedfordshire, England). It is unusual in the presence of a number of species which are the last records of genera common in and typical of the Jurassic (the isocrinid Balanocrinus smithi sp. nov., the millericrinids Apiocrinites gillieroni (de Loriol) and an unnamed species of Apiocrinites, and the cyclocrinid Cyclocrinus variolarius (Seeley)), in association with the first record of the typically Cretaceous Roveacrinidae (Discocrinus integer sp. nov.). Sclerocrinids (Cyrtocrinida) are represented by Torynocinus canon and Torynocrinus globosus sp. nov. The excellent preservation of the material permits new and taxonomically important observations to be made on cup structure in the sclerocrinid and roveacrinid species, and the first description of Torynocrinus brachials. Additionally, the material includes different growth stages and brachials which allow for extended diagnoses of known species. The fauna is also remarkable for the association of differently sized stalked crinoids attached either by cirri or holdfasts, and a pelagic roveacrinid.