The most complete ankylosaur skull ever found in the Wessex Sub-basin (Lower Cretaceous) of the Isle of Wight.

• DOI: 10.7287/peerj.preprints.3277v1
• Publication Date: 2018-01-13T13:53:58Z
• Authors: Stuart Pond
• Keywords: Postcrania

Ankylosaur remains are frequently recovered from the Lower Cretaceous Wealden deposits of Isle Wight, although vast majority these fossils represent postcranial elements and osteoderms. The rarity ankylosaur cranial material means any new specimens important for understanding morphology, palaeoecology evolution taxa. Here we describe a well-preserved partial cranium with associated Wessex Formation at Compton Bay. This is most complete skull ever Sub-basin now held Dinosaur Museum (DI), Sandown, IOW. A highly water worn specimen Sedgwick Earth Sciences was found Chilton Chine in early 1990s assigned to cf. Polacanthus , two crania compared here. consists posterior part basicranium roof including proximal paraoccipital processes, occipital condyle basal tuberosity. Both skulls share characters position some foramina exiting endocranium lateral curvature roof. DI differs by presence well-defined, notched border supraoccipital, flat rostal-caudal dorsal surface, being more bulbous angled ventrally, well-defined nuchal shelf smaller less robust. Differences between may be due sexual dimorphism, ontogeny or they different