Figure 4 : Hands of Chongmingia zhengi gen. et sp. nov. (STM9-9), in comparison with other basal avialans.

From: A new basal bird from China with implications for morphological diversity in early birds

Figure 4

(a) Photograph and (b) line drawing of the right hand of STM9-9; (c–g) line drawings of hands of other basal avialans (not scaled): (c) reconstructed hand of STM9-9; (d) Archaeopteryx (after ref. 7); (e) Jeholornis prima; (f) Sapeornis chaoyangensis (after ref. 11); (g) Confuciusornis sanctus; (h) interpretative drawing of modern bird’s hand with primary remiges in dorsal view. The remiges are attached to the major metacarpal and supported by the minor metacarpal; the lift force (upward purple vector, F) provided by the minor metacarpal is increased by the increased the lever arm (red dashed line, La) when the minor metacarpal is caudally bowed. Abbreviations: I-III, alular, major, minor digit; al-1, the proximal phalanx of the alular digit; am, alular metacarpal; ma-1, 2, phalanges 1, 2 of the major digit; mam, major metacarpal; mc, manual claw; mim, minor metacarpal; uln, ulnare. Scale bars, 10 mm (a). (The photographs and line drawings were taken by Min Wang).