In 1976 John Ostrom published an enlightening paper about the anatomical transformations in the shoulder girdle and forelimb elements along the origin of birds. Most of his ideas were based on comparing Archaeopteryx lithographica with the extant New World vulture Cathartes aura. Ostrom offered innovative ideas about range of movements and function of wing elements in the basal bird Archaeopteryx. Further, he explored anatomical transformations that may have occurred at early stages of the evolution of flight and established several hypothetical steps towards the acquisition of flapping flight in modern birds. Since then, however, our understanding of paravian diversity and anatomy has increased dramatically. Based on novel information derived from recent experiments, and currently available anatomical evidence of basal paravians, the present paper aims to review some important topics on pectoral girdle anatomy related to flight origins. Further, a brief analysis of pectoral girdle osteology and myology of the extant paleognath Rhea americana is also included with the aim to test whether Ostrom’s ideas still remain valid under this new context and based on available phylogenetic and anatomical frameworks.

中文翻译：

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基底帕拉维亚肩带形态的评论：基于非定型的兽脚和古鸟的新数据

1976年，约翰·奥斯特罗姆（John Ostrom）发表了一篇启发性论文，内容涉及鸟类起源时肩the带和前肢元素的解剖学变化。他的大部分想法都基于对始祖鸟石版画与现存的新世界秃鹰Cathartes光环的比较。奥斯特罗姆（Ostrom）提供了有关基础鸟类始祖鸟的机翼运动范围和机翼功能的创新思想。此外，他探索了可能在飞行进化的早期阶段发生的解剖学转变，并建立了一些假设性步骤以实现现代鸟类扑动飞行。但是，自那时以来，我们对巴拉圭族裔的多样性和解剖学的了解急剧增加。根据从最近的实验中获得的新颖信息，以及目前可获得的基底上颚动物的解剖学证据，本文旨在回顾一些与飞行起源有关的胸带解剖学的重要主题。此外，还包括对现存古美洲Rheagnaa胸带的骨学和肌病学的简要分析，目的是测试Ostrom的思想在新的背景下并基于现有的系统发育和解剖学框架是否仍然有效。