New light on the Origin of Birds and Crocodiles

The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades

“…Walker (1970Walker ( , 1972Walker ( , 1990) convincingly showed that sphenosuchians were very closely related to Crocodyliforms, and this hypothesis has been validated by cladistic studies. Since the advent of cladistic methodologies, basal crocodylomorph workers have argued whether the Triassic and Jurassic sphenosuchians represent a monophyletic clade or a paraphyletic group that comprises a series of successive sister taxa of Crocodyliformes.…”

Distribution of Neurons Projecting to the Retina of <i>Caiman crocodilu</i><i>s</i>

“…Recent study of the skull of a crocodile from the Upper Triassic period, Sphenosuchus, sug gests that modern crocodilians may represent a 'frozen stage' in the evo lution of birds insofar as they appear to have undergone little change since this period [Walker, 1972]. Thus, crocodilians such as Caiman may provide excellent material for studying the origins of avian adapta tions.…”

The socio-sexual behaviour of extant archosaurs: implications for understanding dinosaur behaviour

“…Moreover, an approximately 260 million year split between the basal common ancestor of both the crocodilian and avian lineages (e.g. Walker 1972;Norman 1985) only adds to the question as to whether any parental care modes observed between the two clades can be considered as synapomorphies or homoplasies. It is entirely plausible that the parental behaviours of extant archosaurs evolved independently and such problems result in the 'female-only' ancestral care hypothesis being rejected.…”