An enigmatic marine reptile, Hispaniasaurus cranioelongatus (gen. et sp. nov.) with nothosauroid affinities from the Ladinian of the Iberian Range (Spain)

Abstract

An incomplete skull of a marine reptile with an atypical elongation of the postorbital region is described. The find comes from the Muschelkalk facies (Cañete Formation) of the Villora section (Iberian Range, Cuenca Province, Spain), characterised by a shallow marine (intertidal) environment and dated as Ladinian in age. The small skull has a rectangular shape, lacking, as preserved, upper temporal openings and a parietal foramen. The upper temporal openings might be secondarily closed. However, the absence of a parietal foramen and squamosals in the preserved part and the incompleteness of the pterygoids make a posteriorly postponed location of the upper temporal openings also conceivable. Teeth are all broken off but alveolar spaces indicate large and massive maxillary dentition. Micro-CT-data revealed a highly vascularised inner structure of the dorsal skull elements, which might indicate special feeding adaptations. Adding the new find to an existing phylogenetic analysis of Triassic marine reptiles reveals eosauropterygian, especially nothosauroid, affinities. However, morphological differences to nothosauroids justify the erection of a new genus and species for this enigmatic marine reptile. Its atypical morphology, without any extinct or modern analogue, fits well with the continuously increasing diversity of Triassic marine reptiles, exhibiting various specialised feeding strategies urn:lsid:zoobank.org:act:6D75AEC7-A5C5-4844-B71A-8215AB099134