Mosasaurs (Squamata: Mosasauridae) from the Late Cretaceous (Late Maastrichtian) of North Carolina, USA

Abstract

During April 2022, offshore dredging for a storm damage beach renourishment project placed large quantities of Upper Cretaceous (upper Maastrichtian) Peedee Formation sediment onto the shores of Holden Beach in Brunswick County, North Carolina, USA. The Cretaceous sediment is highly fossiliferous and has yielded a rich and diversified assemblage of fossils from mosasaurid reptiles. New fossil material, namely isolated teeth, consists of several dental morphologies from the mosasaur subfamilies Halisaurinae and Mosasaurinae. Five species are recognized: Halisaurus sp., Mosasaurus cf. beaugei Arambourg, 1952, Mosasaurus cf. hoffmannii Mantell, 1829, Prognathodon cf. solvayi Dollo, 1889 and Prognathodontini indet. In this assemblage, prognathodontins predominate, being the most abundant marine reptile find, with all other species being comparatively rare. The mosasaur assemblage of North Carolina shows close affinity with the phosphates of Morocco, containing species typical of both the northern and southern margins of the Mediterranean Tethys. These new discoveries improve our knowledge of the biodiversity of mosasaur fauna from the late Maastrichtian of North Carolina and add to the known paleobiogeographical distribution of these taxa. The material described within was collected courtesy of the efforts of amateur fossil hunters and seasonal tourists combing Holden Beach for fossilized remains.