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Occultonectia
Polycotylidae is a family of plesiosaurs from the Cretaceous, a sister group to Leptocleididae. Polycotylids first appeared during the Albian stage of the Early Cretaceous, before becoming abundant and widespread during the early Late Cretaceous. Several species survived into the final stage of the Cretaceous, the Maastrichtian. With their short necks and large elongated heads, they resemble the pliosaurs, but closer phylogenetic studies indicate that they share many common features with the Leptocleididae and Elasmosauridae. They have been found worldwide, with specimens reported from New Zealand, Australia, Japan, Morocco, the US, Canada, Eastern Europe, and South America. Phylogeny Cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ... after Albright, Gillette and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiopleurodon
''Plesiopleurodon'' (/ˌpliːsiəˈplʊərədɒn/; el, plesios, meaning “near to”, ''pleuro'', meaning “side”, and ''don'', meaning “tooth”) is an extinct genus of Mesozoic marine reptiles, belonging to Sauropterygia, known from the Late Cretaceous of North America. It was named by Kenneth Carpenter based on a complete skull with a mandible, cervical vertebra, and a coracoid. In naming the specimen, Carpenter noted "Of all known pliosaurs, ''Plesiopleurodon wellesi'' most closely resembles ''Liopleurodon ferox'' from the Oxfordian of Europe, hence the generic reference." It was initially described as a pliosaur due to it short neck, a common trait of the family, although it is in the order Plesiosauria. However, later exploration into the relationships of both orders indicate that not all pliosaurs have short necks and not all plesiosaurs have long necks. It is distinguishable by its short neck, elongated head, and comparatively few teeth in the symphysis when comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
