Procompsognathus:theropod, “thecodont” or both?

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Abstract
We show that Procompsognathus triassicus, long held to be a primitive theropod, is actually a paleontological chimera composed of the postcranial skeleton of a Segisaurus-like ceratosaur and the skull of a basal crocodylomorph. We dismember the holotype of P. triassicus on convincing evidence—theropod synapomorphies in the postcranium and crocodylomorph synapomorphies in the skull and referred material. We demonstrate, furthermore, that the holotype skull and a referred skull and partial forelimb belong to the contemporary basal crocodylomorph Saltoposuchus connectens. Saltoposuchus connectens, now with a nearly complete skull, carpus, and manus, is compared in detail to other basal crocodylomorphs. Current opinion maintains that S. connectens is the sister-group to all other crocodylomorphs and that other sphenosuchians constitute a paraphyletic assemblage of sister-taxa to Crocodyliformes. This view is overturned by a quantitative cladistic analysis of 20 characters, which suggests that by the Late Triassic crocodylomorphs had already split into two clades, Sphenosuchia and Crocodyliformes. Sphenosuchians evolved cursorial locomotor capabilities, with a digitigrade manus and particularly gracile long-bone proportions appearing in a subgroup including S. connectens. Crocodyliforms, in contrast, were more heavily armored, with stouter long-bones and a plantigrade manus and pes, and may not have evolved from cursorial predecessors as has generally been assumed.