Cranial morphology of Platypterygius longmani Wade, 1990 (Reptilia : Ichthyosauria) from the Lower Cretaceous of Australia.

摘要: Exceptionally well-preserved remains belonging to the Australian Early Cretaceous (Albian) ichthyosaur Platypterygius longmani Wade, 1990 are described in detail. The material is used reconstruct some of cranial musculature and provide a brief functional analysis skull mandible. Preparation specimens using acetic acid application high-resolution X-ray computed tomographic analyses has revealed many previously unrecorded anatomical details, including absence coronoid squamosal, presence well-developed epipterygoid facets on pterygoid parietal (possibly indicating retention an unossified element). Reconstruction jaw suggests m. adductor mandibulae internus pterygoideus (serving close jaws against inertia drag surrounding water), possibly intramandibularis (acting accentuate static pressure along elongate mandible when were closed). Despite its large size (maximum total body length around 7 m), long, narrow snout P. longmani (together with preserved gut contents) indicates selective feeding relatively small prey such as fish, tetrapods probably cephalopods. Large orbits indicative visual hunter, but extensive external passages for nerves blood vessels might suggest dermal sensory system. massive stapes appears have lost all sound conductive function, serving primarily structural support basicranial region. © 2005 Linnean Society London, Zoological Journal Society, 2005, 145, 583–622.