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Department of Biology, Berry College, Mt Berry Station, GA 30149, USA
Dicynodonts were the dominant primary consumers of the latest Palaeozoic and early Mesozoic ecosystems. Of the 66 currently accepted genera of dicynodonts, three (possibly four) of these occur in the Fremouw Formation of Antarctica (i.e. Kingoria, Lystrosaurus, Myosaurus and ?Kannemeyeria). Modifications to the basic shearing mechanism of the jaws as well as postcranial morphology presumably reflect differences in the physical nature of the food consumed and foraging techniques used by dicynodonts. To date, five dicynodont feeding types have been recognized: invertebrate specialists, grubbers, browsers, forest litter foragers and flexible foragers. Three out of the five ‘central’ dicynodont feeding types are represented among the members of the early Mesozoic Antarctic palaeofauna. In order to more accurately assess systematic and ecomorphic relationships among dicynodonts, comprehensive generic diagnoses (that incorporate postcranial characters) are warranted; suggested revisions to the generic diagnoses of Antarctic dicynodonts are provided. Dicynodont distributions are evaluated in light of ecomorphic considerations, tectonic-orogenic events, sea-level fluctuations, palaeoclimates and floral changes. Available evidence, pertaining to austral taxa, suggests that: (1) Antarctica served as a refugium for kingoriamorphs in the Early Triassic, and (2) the informal members of the Fremouw Formation are correlated with more than one African biozone.
