Warm-Blooded Reptiles?: Existing reptiles are not thought to be endothermic, but what about extinct species? Three large extinct swimming reptiles, the ichthyosaurs, plesiosaurs, and mosasaurs, were active predators in the Mesozoic oceans. Bernard et al. (p. 1379 ; see the Perspective by Motani ) investigated their metabolism by analyzing the oxygen isotopes in their teeth, compared with fish in deposits from a variety of ocean environments. The data imply that the ichthyosaurs and plesiosaurs, which were both pursuit predators, probably controlled their own temperature. The data for the mosasaurs, which are thought to have hunted by ambush, are more equivocal.

Aristonectes parvidens Cabrera, 1941, and Morturneria seymourensis (Chatterjee and Small, 1989), two plesiosaurs from the Maastrichtian of South America and Antarctica whose phylogenetical position is controversial, are reviewed and found to be congeneric and conspecific. Most differences between the two type specimens are interpreted as related to ontogenetic growth: Morturneria is based on an immature, whereas Aristonectes is based on an adult, probably an old individual. Aristonectes exhibits an unique set of characters among Plesiosauria: a low and wide ogival skull, a paired vomeronasal fenestra, a mandible high anteriorly with a very short and high symphysis, a homodont dentition composed of numerous, strongly outwardly directed and poorly ornamented teeth (dental formula: 10–13 premaxillary, at least 51 maxillary and probably 60–65 dentary teeth, depending upon individual ontogeny). Moreover, Aristonectes shares several synapomorphies with the elasmosaurid clade, mainly strongly binocular-...

Marine reptiles are an adaptive assemblage including a mosaic of forms with fully marine groups (ichthyosaurs, “nothosaurs”;, plesiosaurs, placodonts, thalattosaurs and hupehsuchians), as well as groups containing continental representatives (turtles, crocodiles, lizards and snakes). Forty‐six families of marine reptiles are recorded during the Mesozoic. The fossil record of marine reptiles is punctuated by two major extinctions at the Middle‐Late Triassic transition (loss of 64% of families) and at the Cretaceous‐Tertiary boundary (36% of families died out). The Ladinian‐Carnian boundary event coincides with an important regressive phase and affects essentially coastal forms. The K/T boundary is characterized by selective extinctions among marine reptiles, probably linked with a break in the food chain.

A large azhdarchid pterosaur is described from the Late Maastrichtian phosphatic deposits of the Oulad Abdoun Basin, near Khouribga (central Morocco). The material consists of five closely associated cervical vertebrae of a single individual. The mid-series neck vertebrae closely resemble those of azhdarchids Quetzalcoatlus and Azhdarcho in that they are elongate, with vestigial neural spines, prezygapophysial tubercles, a pair of ventral sulci near the prezygapophyses, and without pneumatic foramina on the lateral surfaces of the centra. The Moroccan pterosaur is referred to a new genus and species of Azhdarchidae: Phosphatodraco mauritanicus gen. et sp.nov. It is mainly characterized by a very long cervical vertebra eight, bearing a prominent neural spine located very posteriorly. Based on comparisons with azhdarchid vertebrae, the estimated wing span of Phosphatodraco is close to 5 m. This discovery provides the first occurrence of Late Cretaceous azhdarchids in northern Africa. Phosphatodraco is one of the few azhdarchids known from a relatively complete neck and one of the latest-known pterosaurs, approximately contemporaneous with Quetzalcoatlus .