Using synchrotron imaging of two new early Jurassic crocodilians to understand locomotion and growth strategies in early crocodile evolution

Modern crocodiles are often seen as sluggish, primitive animals with sprawling postures and aquatic habits remaining unchanged over millions of years. However, they are derived from small, active protosuchians with erect postures. Understanding the biology of these extremely rare early crocodilians from the early Jurrasic is therefore critical for assessing early crocodilian history. We propose to scan two new early South African crocodilians that will assist in our understanding of this group and where the modern traits evolved in the phylogeny. The very gracile specimens preserve elements of the skull, body armour, and extremely long limbs. In this study, we propose to use PPC-SRμCT to image the complete fossil and further at submicron voxel size to image osteohistological cross-sections of the long bones of both fossils. These novel data on the evolution of different growth strategies, locomotion and ecology will help understand the early diversification of crocodilians.