Systematic Position of Palaeortyx (Aves, ?Phasianidae) and Notes on the Evolution of Phasianidae

Postcranial skeletal morphology of the Oligocene-Miocene fossil galliform genus Palaeortyx is compared with modern representatives of Phasianoidea. In particular, Palaeortyx is compared with the modern African Ptilopachus, which was recently transferred to the American family Odontophoridae, to which Palaeortyx was originally assigned. It is shown here that Palaeortyx lacks derived features of Odontophoridae, and all the apparent similarities (including the deep fossa pneumotricipitalis dorsalis of the humerus) represent plesiomorphies of the clade Odontophoridae+Phasianidae or even a higher clade. No essential similarity between Palaeortyx and Ptilopachus can be observed. The greater similarity between Palaeortyx and Rollulinae is here considered as being plesiomorphic for Phasianidae s.s. It is thus concluded that Palaeortyx most likely represents a basal member of the Phasianidae and diverged before the Rollulinae and Phasianinae dichotomy. The evolutionary history of this genus and of the Phasianidae in general is discussed.