Figure 5.

Hypothesized phylogenetic relationships of Isisfordia duncani and key postcranial transformations that occurred during the origin of eusuchian crocodyliforms. (a) Stratigraphically calibrated strict consensus of six equally optimal trees resulting from parsimony analysis of 176 characters in 45 taxa (46 if Allodaposuchus is included). Thick solid lines represent known minimal ranges (see Brochu 1997 and references therein), while the abbreviations above the names denote the area in which the taxon occurs (AF, Africa; ASIA, Asia; AUST, Australia; EUR, Europe; NA, North America; SA, South America; SE ASIA, Southeast Asia). See electronic supplementary material for character list, data matrix, analysis protocol, apomorphy list and bootstrap support indices. (b) Key postcranial transformations (sagittal segmentation of the paravertebral shield and the acquisition of procoelous vertebrae) that took place during the evolutionary transition from advanced neosuchians (represented by Bernissartia and Susisuchus) to basal eusuchians (Isisfordia) and, finally, crocodylians (represented by Crocodylus porosus). Abbreviations: bw, body wall musculature; derm, dermis; dermost acc, accessory osteoderm; dermost paravert, paravertebral osteoderm; gast, gastral rib; m epax, epaxial musculature; m rect, musculus rectus abdominalis; ms ilcost, myoseptum of the musculus iliocostalis; seg vertcost, vertebral segment of a thoracic rib; vert, vertebra; vis, viscera.