Scheyer et al. have examined the skeleton of the crocodylian P. mirandai. All other crocodylians examined to date only have two vertebrae in their sacrum, making P. mirandai the first reported case of a crocodylian with three sacral vertebrae. This is likely due to a change in the expression of the Hox genes in this species. Indicated as prz in the image, the prezygagophysis connects each vertebra with the anterior one in the spine.