Nature 279, 234 - 236 (17 May 1979); doi:10.1038/279234a0

New look at the origin of birds and crocodiles

K. N. WHETSTONE^* & L. D. MARTIN

Museum of Natural History and Department of Systematics and Ecology, University of Kansas, Lawrence, Kansas 66045
^*Present address: Dept of Palaeontology, British Museum of Natural History, Cromwell Road, London SW7 UK.

DURING the period 1926−73 most ornithologists and vertebrate palaeontologists supported Heilmann's theory of avian origins. Heilmann¹ argued that all dinosaurs and pterosaurs were too specialised to have been ancestral to birds. Instead he chose to derive birds directly from a primitive group of Triassic archosaurs, the Pseudosuchia. Heilmann's theory has recently been challenged by Walker²⁻⁴, who has suggested that birds evolved from an early crocodilian, and by Ostrom⁵⁻¹⁰, who argued that birds descended from theropod dinosaurs. We recently began a study of the otic region in archosaurs and birds, in search of advanced, homologous features which would give definitive support to one theory or the other. The results of this investigation, discussed below, strongly support a hypothesis of a common pseudosuchian origin for birds and crocodiles, independent of dinosaurs.

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