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Full-Text Articles in Aquaculture and Fisheries
Morphologic And Ontogenetic Patterns In Elasmosaur Neck Length, With Comments On The Taxonomic Utility Of Neck Length Variables, F. Robin O’Keefe, Norton Hiller
Morphologic And Ontogenetic Patterns In Elasmosaur Neck Length, With Comments On The Taxonomic Utility Of Neck Length Variables, F. Robin O’Keefe, Norton Hiller
Biological Sciences Faculty Research
Elasmosaur cervical vertebrae are common fossils, but their taxonomic utility is limited due to a lack of understanding concerning their shape within and among taxa. In this paper, we analyze data from complete elasmosaur necks in an attempt to quantify and understand the variation in centrum dimensions. In accord with previous studies, variation in cervical centrum shape is found to stem from at least three sources: ontogeny, intracolumn variation, and intercolumn or taxonomic variation. Ontogenetic variability seems reminiscent of that seen in Cryptoclidus, with an overall positive allometry in the length of all centra that is accentuated in the mid-cervical …
A Cladistic Analysis And Taxonomic Revision Of The Plesiosauria (Reptilia: Sauropterygia), F. Robin O’Keefe
A Cladistic Analysis And Taxonomic Revision Of The Plesiosauria (Reptilia: Sauropterygia), F. Robin O’Keefe
Biological Sciences Faculty Research
The Plesiosauria (Reptilia: Sauropterygia) is a group of Mesozoic marine reptiles known from abundant material, with specimens described from all continents. The group originated very near the Triassic–Jurassic boundary and persisted to the end- Cretaceous mass extinction. This study describes the results of a specimen-based cladistic study of the Plesiosauria, based on examination of 34 taxa scored for 166 morphological characters. The Pliosauroidea is found to by polyphyletic due to the inclusion of the Polycotylidae; this second clade is instead a member of the Plesiosauroidea, and thus more closely related to elasmosaurs than to other ‘pliosaurs’. Characters of body proportion …