Darwinopterus carpus and another 5th manual digit

I appreciate it when authors provide close-ups of the pterosaur carpus. It gives me a chance to once again document the near universal presence of a vestigial manual digit 5 and other ptero traits missed by other workers.

Figure 1. The carpus of Darwinopterus linglongtaenis. Vesitigial digit 5 is scattered on metatarsal 4. The pteroid articulates in the saddle of the radiale. The preaxial carpal articulates on the first distal carpal now fused to the other distal carpals in a syncopal.

Figure 1. Click to enlarge. The carpus of Darwinopterus linglongtaenis. Vesitigial digit 5 is scattered on metatarsal 4. The pteroid articulates in the saddle of the radiale. The preaxial carpal articulates on the first distal carpal now fused to the other distal carpals in a syncopal.

Here digit 5 is scattered, but all the elements are there. In red: distal carpal 5. In green: metacarpal 5. In blue: two proximal phalanges. In amber: a sharp ungual. This matches the pattern seen in basal fenestrasaurs in which manual digit 5 is not a vestige.

Note the pteroid is located in the saddle of the radiale (Peters 2009) and disconnected from the preaxial carpal (both former centralia, having migrated to the medial wrist, convergent with the mammalian prepollex).

References
Peters D 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29:1327-1330.
Wang X, Kellner AWA, Jiang S-X, Cheng X, Meng Xi and Rodrigues T 2010
. New long-tailed pterosaurs (Wukongopteridae) from western Liaoning, China. Anais da Academia Brasileira de Ciências 82 (4): 1045–1062. pdf online

wiki/Kunpengopterus

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