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- <p>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 such as neck length and head size are very labile, with the ‘pliosauromorph’ body plan evolving three times, while extremely long necks evolved in two clades. Characters from the entire skeleton support these relationships, although characters of the skull roof and palate are especially useful. Lastly, a new genus and species, Hauffiosaurus zanoni, is named based on German material of Toarcian age.</p> (1)
- Aspect ratio (1)
- Ecomorphology (1)
- Elasmosaur (1)
- Flight (1)
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Articles 1 - 3 of 3
Full-Text Articles in Aquaculture and Fisheries
Ecomorphology Of Plesiosaur Flipper Geometry, F. O’Keefe
Ecomorphology Of Plesiosaur Flipper Geometry, F. O’Keefe
F. Robin O’Keefe
The Plesiosauria is an extinct group of marine reptiles once common in mesozoic seas. Previous work on plesiosaur hunting styles has suggested that short-necked, large-headed animals were pursuit predators, whereas long-necked, small-headed animals were ambush predators. This study presents new data on the aspect ratios (ARs) of plesiosaur flippers, and interprets these data via comparison with AR in birds, bats and aircraft. Performance trade-offs implicit in AR variation are well-understood in the context of aircraft design, and these trade-offs have direct ecomorphological analogues in birds and bats. Knowledge of these trade-offs allows interpretation of variation in plesiosaur AR. By analogy, …
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
F. Robin O’Keefe
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 …
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
F. Robin O’Keefe
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 …