1. University of Cambridge 1 Department of Earth Sciences , , Cambridge, CB2 3EQ , UK
2. Palaeontological Institute and Museum, University of Zurich 2 , 8006 Zürich , Switzerland
3. Royal Veterinary College 3 Structure and Motion Laboratory, Department of Comparative Biomedical Sciences , , North Mymms, AL9 7TA , UK
4. McDonald Institute for Archaeological Research, University of Cambridge 4 , Cambridge, CB2 3ER , UK