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

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A partial skeleton (including both skull and postcranium) and referred dental material attributable to a new species of Oligo-Miocene kangaroo, Nambaroo gillespieae, are described from the Riversleigh World Heritage Area, northwestern Queensland, Australia. The holotype specimen is one of the oldest articulated fossil kangaroo skeletons yet discovered and includes the first postcranial material definitively attributable to the extinct family Balbaridae. Functional-adaptive analysis (including comparisons with modern taxa) of the hindlimb and pedal elements suggests consistent use of quadrupedal progression rather than true hopping. Robust forelimbs and an opposable first pedal digit (lost in most macropodoids) might also indicate limited climbing ability. Cladistic analysis of 104 discrete cranio-dental and postcranial characters coded for 25 ingroup and one outgroup taxon places N. gillespieae in a plesiomorphic sister clade (also containing other Balbarids and the propleopine Ekaltadeta ima) to all other macropodoids. This result supports recent revisions to the classification of kangaroos, which recognize Balbaridae as the most basal macropodoid family-level taxon.