Richard Forrest

Book

Not Walking with dinosaurs: the swimming and flying reptiles of the mesozoic

Leicester Literary & Philosophical Society Geology Section. Saturday School Symposium 21 FEB 2004

Plesiosaur taxonomy is becoming ever more complicated. It was once seen as a simple dichotomy of long neck/small head (plesiosauroid) versus short neck/big head (pliosauroid). This view does not stand up to scrutiny. There is a range of forms, including fairly long-necked forms with rather large heads. Reconstructions of Plesiosaurs in general show similar body forms, the variation being in the neck and head. This is not the case. Some had rather flattened bodies; others were more barrel-shaped.
In biomechanical terms the long necks'are counterintuitive, yet the extreme extension of the neck occurred in at least two lineages. We don't know what Plesiosaurs were doing, but whatever it was, they were doing it very well. They were major predators in the marine ecology for 100 million years! An understanding of the biomechanical constraints is needed to identify taxonomic differences. The use of different structural solutions to achieve the same mechanical result demonstrates taxonomic diversity. A case in point is the range of different strategies for stiffening the Plesiosaur neck.

English