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Open AccessArticle

On the Preservation of the Beak in Confuciusornis (Aves: Pygostylia)

Biology Department, Centre College, 600 W. Walnut St. Danville, KY 40422, USA
Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing 100044, China
CAS Center for Excellence in Life and Paleoenvironment, Beijing 10010, China
Authors to whom correspondence should be addressed.
Diversity 2019, 11(11), 212;
Received: 27 October 2019 / Revised: 9 November 2019 / Accepted: 10 November 2019 / Published: 11 November 2019
(This article belongs to the Special Issue Origins of Modern Avian Biodiversity)
The Confuciusornithiformes represent the most stem-ward avian occurrence of an edentulous rostrum. Although a keratinous beak is widely considered to have covered the rostrum in confuciusornithiforms, this feature is almost never preserved, having been previously reported only in the holotype of Confuciusornis dui and the holotype of Eoconfuciusornis zhengi. This strongly contrasts with the widespread preservation of the keratinous sheaths that cover the manual and pedal ungual phalanges. Here, we report on a third occurrence of a preserved rhamphotheca in a specimen of Confuciusornis sanctus. We illuminated the preserved traces using laser-stimulated fluorescence. Similarly to E. zhengi, the rhamphotheca has been preserved only as a two-dimensional trace, whereas ungual sheaths are preserved in three dimensions. In contrast to the traces preserved in C. dui, the rhamphotheca in the discussed specimen of C. sanctus is straight rather than upturned. This hints towards hidden morphological diversity within the thousands of Confuciusornis specimens, in which species may be further differentiated by soft tissue features or behaviors, much like many living birds, that cannot be detected in fossils, even with exceptional preservation. View Full-Text
Keywords: beak; rhamphotheca; Confuciusornithidae; Confuciusornithiformes; preservation; hidden diversity; Jehol biota beak; rhamphotheca; Confuciusornithidae; Confuciusornithiformes; preservation; hidden diversity; Jehol biota
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MDPI and ACS Style

Falk, A.; O’Connor, J.; Wang, M.; Zhou, Z. On the Preservation of the Beak in Confuciusornis (Aves: Pygostylia). Diversity 2019, 11, 212.

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