Wednesday, November 7, 2018

[PaleoOrnithology • 2012] Elaborate Plumage Patterning in A Cretaceous Bird

Confuciusornis sp.

in Li, Clarke, Gao, et al​., 2018. 
  DOI:  10.7717/peerj.5831 
Reconstruction by Velizar Simeonovski.

Integumentary patterns and colors can differentiate species, sexes, and life changes and can inform on habitat and ecology. However, they are rarely preserved in the fossil record. Here, we report on an extremely well-preserved specimen of the Cretaceous bird Confuciusornis with unprecedented complexity, including small spots on the wings, crest, and throat. Morphological and chemical evidence suggest that these patterns are produced by melanin, but unusual preservation prevents assignment of specific colors. Based on comparisons with extant birds, these patterns were likely used for camouflage, although other functions including sexual signaling cannot be ruled out. Our data show that even more elaborate plumage patterns than the spangles in Anchiornis and stripes in Sinosauropteryx were present at a relatively early stage of avian evolution, showing the significance of coloration and patterning to feather evolution.

Figure 1: Evidence of plumage diversity in the Confuciusornithidae from the new specimen (CUGB P1401). (A–D) The primary slab of CUGB P1401 showing details of the plumage including crest ornamentation on the (B) top and (C) back of the head as well as on the (D) secondary and (E) gular feathers. Dots indicate locations sampled for Raman and morphological analyses. Colored dots correspond to locations of SEM images and Raman spectra in Fig. 2. 

Figure 6: Reconstruction of the plumage in CUGB P140. Morphological data and probable eumelanin signatures are consistent darker preserved regions as associated with dark colors in the fossil (sampling regime explained in Fig. 1).
Reconstruction by Velizar Simeonovski.

The elaborate spotting on this specimen exceeds that found in exceptionally-preserved troodontids and compsognathids and rivals that in modern birds, suggesting that plumage patterns evolved greater complexity through avian evolution. This hypothesis remains to be tested as more exceptionally-preserved specimens are described.

Quanguo Li, Julia A. Clarke, Ke-Qin Gao, Jennifer A. Peteya and Matthew D. Shawkey​. 2018. Elaborate Plumage Patterning in A Cretaceous Bird.  PeerJ. 6:e5831.   DOI:  10.7717/peerj.5831

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