An overview of the pterosaur assemblage from the Cambridge Greensand (Cretaceous) of Eastern England

Abstract

The Cambridge Greensand, a remaniC deposit that crops out in Cambridgeshire. eastern England, has yielded numerous. though fragmentary, late Early Cretaceous (Albian) vertebrate fossils including more than 2000 isolated pterosaur bones. So far. 32 species of pterosaur have been proposed in connection with the Cambridge Greensand material. but there has been and continues to be considerable confusion concerning the validity of these taxa, their relationships to each other and to other pterosaurs, and the material upon which they were established. A comprehensive systematic revision identified eleven valid species distributed among three families: the Ornithocheiridae (Ornithoeheirus sirnus and possibly a second. as vet un- named species of Ornithoeheirus. Coloborhynchus capito, Coloborhynchus sedgwickii, Anhangiiern cuvieri, and An1iririgiierrr jirtoni); the Lonchodectidae (Lonchodectes compressirostris, Lonchodectes rnachaerorhynchus, Lonchorlrcres niicrotiori and Lonchodecies plarystornus): and a species of edentulous pterosaur (Ornithostonin sedgwicki) that may represent the earliest record for the Pteranodontidac. It is possible that some of the taxa currently recognised represent sexual dimorphs (Colohor- hynchus cupito and Coloborhynchus sedgwickii, Lonchodectes compressirostris and Lonchodectes mrrc~i~ierijr~i~richrts), or dis- junct populations of a single species (Ornithocheirus sirnus and Ornithocheirus sp., Lonchodectes conipressirosrri.v and Loriclio- dectes microdon) and that there may be as few as seven valid species, but the Cambridge Greensand pterosaurs are too poorly known to demonstrate this at present. The Cambridge Greensand pterosaur assemblage is similar to a slightly youngel-. but much smaller assemblage from the Lower Chalk of England and shares some elements, such as ornithocheirids. in com- mon with many other late Early and early Late Cretaceous assemblages. It is distinguished by the absence of tapejarids and the presence of Lonchodectes which, so far, is only known from the Cretaceous of England. The disparity in taxonomic composition is possibly related to ecological differentiation, and might also reflect some provincialism in late Early and early Late Cretaceous pterosaur faunas.