Falk Amanda R, Kaye Thomas G, Zhou Zhonghe, Burnham David A
Centre College, Department of Biology, Danville, KY, United States of America.
Burke Museum of History and Culture, Seattle, WA, United States of America.
PLoS One. 2016 Dec 14;11(12):e0167284. doi: 10.1371/journal.pone.0167284. eCollection 2016.
In this paper we report the discovery of non-plumage soft tissues in Confuciusornis, a basal beaked bird from the Early Cretaceous Jehol Biota in northeastern China. Various soft tissues are visualized and interpreted through the use of laser-stimulated fluorescence, providing much novel anatomical information about this early bird, specifically reticulate scales covering the feet, and the well-developed and robust pro- and postpatagium. We also include a direct comparison between the forelimb soft tissues of Confuciusornis and modern avian patagia. Furthermore, apparently large, fleshy phalangeal pads are preserved on the feet. The reticulate scales, robust phalangeal pads as well as the highly recurved pedal claws strongly support Confuciusornis as an arboreal bird. Reticulate scales are more rounded than scutate scales and do not overlap, thus allowing for more flexibility in the toe. The extent of the pro- and postpatagium and the robust primary feather rachises are evidence that Confuciusornis was capable of powered flight, contrary to previous reports suggesting otherwise. A unique avian wing shape is also reconstructed based on plumage preserved. These soft tissues combined indicate an arboreal bird with the capacity for short-term (non-migratory) flight, and suggest that, although primitive, Confuciusornis already possessed many relatively advanced avian anatomical characteristics.
在本文中，我们报告了在中国东北早白垩世热河生物群的基干有喙鸟类孔子鸟中发现的非羽毛软组织。通过激光激发荧光对各种软组织进行了可视化和解读，提供了许多关于这种早期鸟类的新颖解剖学信息，特别是覆盖脚部的网状鳞片，以及发育良好且强健的前翼膜和后翼膜。我们还对孔子鸟的前肢软组织与现代鸟类翼膜进行了直接比较。此外，脚部保存有明显较大的肉质指垫。网状鳞片、强健的指垫以及高度弯曲的爪有力地支持了孔子鸟是一种树栖鸟类的观点。网状鳞片比盾形鳞片更圆且不重叠，从而使脚趾具有更大的灵活性。前翼膜和后翼膜的范围以及强健的初级飞羽羽轴证明孔子鸟具备动力飞行能力，这与之前的一些相反观点的报道不同。基于保存的羽毛还重建了一种独特的鸟类翅膀形状。这些软组织综合起来表明孔子鸟是一种具有短期（非迁徙性）飞行能力的树栖鸟类，并且表明，尽管孔子鸟较为原始，但它已经拥有许多相对先进的鸟类解剖学特征。
