Fred Ruhe
Well-known member
THE BIOLOGY OF EOCONFUCIUSORNIS
O'CONNOR, Jingmai, Institute of Vertebrate Paleontology & Paleoanthropology, Beijing, China; ZHENG, Xiaoting, Shandong Tianyu Museum of Nature, Pingyi, China; WANG, Xiaoli, Lingyi University, Lingyi, China; PAN, Yanhong, Nanjing, China; ZHOU, Zhonghe, Beijing, China
The basal confuciusornithiform Eoconfuciusornis is the oldest and most primitive bird with a beak and pygostyle. New information on this taxon reveals evolutionary trends in the Confuciusornithiformes, the most numerous clade of birds in the Jehol. The manual ungual disparity present in Confuciusornis is lesser developed in Eoconfuciusornis, and the deltopectoral crest of the humerus is not perforated by a foramen as it is in Confuciusornis. The second known specimen of Eoconfuciusornis preserves unusual soft tissue traces of the ovary, propatagium, and nearly its complete plumage including pennaceous feathers on the alular digit shorter than those that form the alula in ornithothoracines. The ovarian follicles preserve a stronger hierarchy than observed in Jeholornis and enantiornithines, consistent with osteohistological data, which both indicate that a higher basal metabolic rate evolved independently and apparently early in the evolution of the confuciusornithiforms. The preserved internal soft tissue of the propatagium, documented for the first time, is interpreted as the perimineralized remnants of the collagenous fascial sheet and fascial curtain. The internal structure bears remarkable similarity to that in living birds although the apparent absence of the propatagial ligament suggests that the confuciusornithiform propatagium could produce lift but not prevent hyperextension. The remiges preserve remnants of their Original patterning, supported by observable differences in melanosome morphology. The tail lacks rectrices, indicating that the earliest known confuciusornithiforms were sexually dimorphic in their plumage.
O'CONNOR, Jingmai, Institute of Vertebrate Paleontology & Paleoanthropology, Beijing, China; ZHENG, Xiaoting, Shandong Tianyu Museum of Nature, Pingyi, China; WANG, Xiaoli, Lingyi University, Lingyi, China; PAN, Yanhong, Nanjing, China; ZHOU, Zhonghe, Beijing, China
The basal confuciusornithiform Eoconfuciusornis is the oldest and most primitive bird with a beak and pygostyle. New information on this taxon reveals evolutionary trends in the Confuciusornithiformes, the most numerous clade of birds in the Jehol. The manual ungual disparity present in Confuciusornis is lesser developed in Eoconfuciusornis, and the deltopectoral crest of the humerus is not perforated by a foramen as it is in Confuciusornis. The second known specimen of Eoconfuciusornis preserves unusual soft tissue traces of the ovary, propatagium, and nearly its complete plumage including pennaceous feathers on the alular digit shorter than those that form the alula in ornithothoracines. The ovarian follicles preserve a stronger hierarchy than observed in Jeholornis and enantiornithines, consistent with osteohistological data, which both indicate that a higher basal metabolic rate evolved independently and apparently early in the evolution of the confuciusornithiforms. The preserved internal soft tissue of the propatagium, documented for the first time, is interpreted as the perimineralized remnants of the collagenous fascial sheet and fascial curtain. The internal structure bears remarkable similarity to that in living birds although the apparent absence of the propatagial ligament suggests that the confuciusornithiform propatagium could produce lift but not prevent hyperextension. The remiges preserve remnants of their Original patterning, supported by observable differences in melanosome morphology. The tail lacks rectrices, indicating that the earliest known confuciusornithiforms were sexually dimorphic in their plumage.
