Forty new specimens of Ichthyornis provide unprecedented insight into the postcranial morphology of crownward stem group birds.
Forty new specimens of Ichthyornis provide unprecedented insight into the postcranial morphology of crownward stem group birds.
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四十个新标本的鱼鸟提供了前所未有的洞察颅后形态冠向干组鸟类。
DOI：
10.7717/peerj.13919
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发表时间：
2022
期刊：
影响因子：
2.7
通讯作者：
Field, Daniel J.
中科院分区：
文献类型：
--
作者：
Benito, Juan;Chen, Albert;Wilson, Laura E.;Bhullar, Bhart-Anjan S.;Burnham, David;Field, Daniel J.
鱼鸟长期以来一直被认为是了解恐龙-鸟类转变最新阶段的一个至关重要的化石分类单元，但自 19 世纪对部分骨骼的初步描述以来，几乎没有发现任何重要的新颅后材料。在这里，我们提供了来自 40 个先前未描述的标本的鱼鸟颅后形态的新信息，提供了迄今为止对鱼鸟颅后骨骼最完整的形态学评估。新材料包括四个部分完整的骨骼和许多保存完好的孤立元素，使得新的解剖学观察成为可能，例如以前未描述过的中生代真鸟类的肌肉附件。在鱼鸟以前未知或代表性较差的元素中，新标本包括几乎完整的轴向系列、下锁骨分叉、桡骨、腓骨、完整的跗跖骨和基本的下跗骨，以及中生代鸟类中第一个已知的几乎完整的三维胸骨之一。几个踏板指骨被保存下来，显示出明显增大的小腿，可能与用脚推动游泳有关。虽然可以诊断为鱼鸟，但新标本表现出很大程度的形态变异，其中一些可能与个体发生变化有关。结合我们的新数据并采用替代形态学数据集的系统发育分析恢复了鱼鸟属的Hesperornithes和Iaceornis的干系，符合最近关于鸟类干群最冠部分的拓扑结构的一些假设，并且我们为相关鸟类分支建立了系统发育定义的分支名称，以帮助促进未来工作中一致的论述。这些标本提供的新信息提高了我们对冠群鸟类起源之前最冠的非新鸟类鸟类形态进化的理解。
Ichthyornis has long been recognized as a pivotally important fossil taxon for understanding the latest stages of the dinosaur–bird transition, but little significant new postcranial material has been brought to light since initial descriptions of partial skeletons in the 19th Century. Here, we present new information on the postcranial morphology of Ichthyornis from 40 previously undescribed specimens, providing the most complete morphological assessment of the postcranial skeleton of Ichthyornis to date. The new material includes four partially complete skeletons and numerous well-preserved isolated elements, enabling new anatomical observations such as muscle attachments previously undescribed for Mesozoic euornitheans. Among the elements that were previously unknown or poorly represented for Ichthyornis, the new specimens include an almost-complete axial series, a hypocleideum-bearing furcula, radial carpal bones, fibulae, a complete tarsometatarsus bearing a rudimentary hypotarsus, and one of the first-known nearly complete three-dimensional sterna from a Mesozoic avialan. Several pedal phalanges are preserved, revealing a remarkably enlarged pes presumably related to foot-propelled swimming. Although diagnosable as Ichthyornis, the new specimens exhibit a substantial degree of morphological variation, some of which may relate to ontogenetic changes. Phylogenetic analyses incorporating our new data and employing alternative morphological datasets recover Ichthyornis stemward of Hesperornithes and Iaceornis, in line with some recent hypotheses regarding the topology of the crownward-most portion of the avian stem group, and we establish phylogenetically-defined clade names for relevant avialan subclades to help facilitate consistent discourse in future work. The new information provided by these specimens improves our understanding of morphological evolution among the crownward-most non-neornithine avialans immediately preceding the origin of crown group birds.
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影响因子：
3.7
作者：
Bell A;Chiappe LM
通讯作者：
Chiappe LM
影响因子：
2.6
作者：
Bell, Alyssa;Chiappe, Luis M.
通讯作者：
Chiappe, Luis M.
DOI：
10.1660/062.114.0111
发表时间：
2011-04-01
期刊：
Transactions of the Kansas Academy of Science
影响因子：
--
作者：
Bell, Alyssa;Everhart, Michael J.
通讯作者：
Everhart, Michael J.
影响因子：
3.7
作者：
Bailleul AM;Scannella JB;Horner JR;Evans DC
通讯作者：
Evans DC
DOI：
10.1016/j.palaeo.2017.12.010
发表时间：
2019-01-01
影响因子：
3
作者：
Bell, Alyssa;Wu, Yun-Hsin;Chiappe, Luis M.
通讯作者：
Chiappe, Luis M.