The palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous), Isle of Wight, Southern England

Abstract

Abstract The Wessex Formation on the Isle of Wight yields an Early Cretaceous dinosaur fauna. Sedimentological evidence shows that this represents a mosaic of fluvial, floodplain and lacustrine environments within a relatively narrow east-west oriented valley. The vegetational cover on the alluvial plain had a savannahor chaparral-like aspect, probably of low productivity. The relative scarcity of small aquatic vertebrates, absence of coals, abundance of oxidixed sediments and the presence of immature calcretes indicate seasonal water supply. The dinosaur taxa compising the Wessex Formation faunal assemblage represent a single palaeocommunity which inhabited the local alluvial plain, although some species may have been transient. The fauna had a relatively low diversity and this is attributed to the low productivity of the local vegetation. Iguanodontids and Hypsilophodon were the dominant elements in the fauna. In contrast to Late Jurassic dinosaur faunas, sauropods are less abundant in the Wessex Formation, although they remain taxonomically diverse. It is concluded that climatic changes which took place in the Late Jurassic or Early Cretaceous resulted in the appearance of flow productivity vegetation and that this was incapable of supporting large sauropod populations.