A new crocodylian from the Early Eocene of south-eastern Queensland and a preliminary investigation of the phylogenetic relationships of crocodyloids

Abstract

Kambara implexidens sp. nov. is the second crocodylomorph from the Early Eocene (Ypresian) Tingamarra Local Fauna at Boat Mountain, near the township of Murgon, southeastern Queensland. Kambara is now the best represented genus of early Tertiary crocodylomorphs yet collected from Australia. The new species differs from Kambara murgonensis in several features, the most significant of which is possession of an interlocking dentition. Both species occur in a single stratigraphic horizon, possibly indicating two sympatric populations. The presence of adults and hatclings, coupled with the rarity of intermediately sized animals in the Murgon sample suggests the area may have been used as a nesting ground by one or both species. The new material permits a detailed reassessment of the phylogenetic relationships of Australia's Tertiary crocodylians, and provides impetus for a preliminary investigation into the relationships of many putative crocodylid stem taxa. We define Crocodyloidea and Crocodylidae as the des...