Figure 2
From: Vocal specialization through tracheal elongation in an extinct Miocene pheasant from China
Photo and line drawing of the thoracic region of the holotype specimen of Panraogallus hezhengensis (HMV 1876). The tracheal loop is indicated by the red line and compared with that in the Helmeted curassow (Pauxi pauxi) (c), Black curassow (Crax alector) (d), Crested guineafowl (Guttera pucherani) (e), and Wood grouse (Tetrao urogallus) (f), which are adapted from ref.48. Anatomical abbreviations: cav–free caudal vertebrae, cc–cnemial crest, cmc–carpometacarpus, dc–deltopectoral crest, fi–fibula, ft–femur trochanteric crest, fu–furcula, hh–humeral head, if–ilioischiadicum foramen, ml?–muscular line, pat–patches, pd–pedal digits, pp–preacetabular process, py–pygostyle, pr–projection for the spur attachment on the tarsometatarsus, ses–sesamoid bone, st–sternum, tr–tracheal ring, tra–trabecula, and trc–tracheal coiling/loop.
