报告人：郭北辰

报告题目：Tracing macroevolutionary transformations of avian quadrate morphology

鸟类方骨的宏观演化历程

合作导师： 胡晗

评审委员会主任： 周忠和

委员（按姓氏拼音顺序）： 李小强、李志恒、王博、王敏、汪筱林 

时间：2025年12月1日 下午15:30

地点：首建9楼会议室

内容简介：

In birds, the quadrate acts as a hinge between the lower jaw and the skull, playing a key role in cranial kinesis. Thus, the evolution of avian quadrate form may be closely associated with feeding mechanics; however, the extreme variability of quadrate morphology among extant birds has dissuaded previous work. Here, we investigated morphological evolution of the quadrate spanning all major lineages of extant birds and key crown- and stem-bird fossils. With the first comprehensively homology-led anatomical atlas of avian quadrate morphology, we applied geometric morphometrics to quantitatively explore morphological evolution of the quadrate to investigate the ecomorphological relationships between the quadrate and an array of ecological categories and to trace the evolution of quadrate form throughout avian evolutionary history. We found feeding ecology do not predict quadrate morphology, whereas non-ecological factors, such as allometry and phylogeny, are strongly associated with quadrate form. This work illustrates that the quadrate of crown birds has evolved as an integrated unit, exhibiting strong associations with the morphologies of neighbouring bones with which it articulates; collectively, these results suggest a complex macroevolutionary scenario in which quadrate morphology evolved jointly with other elements of the avian kinetic system. Our results also illustrate the importance of incorporating fossil taxa into three-dimensional reconstructions of ancestral shape, as fossil-informed ancestral geometric reconstructions differ substantially from three-dimensional reconstructions of quadrate shape lacking fossils. These ancestral reconstructions help elucidate important aspects of the morphology and function of the avian feeding apparatus early in crown bird evolution.

在鸟类中，方骨（quadrate）連結下颌与颅骨，在鸟类頭颅能動性中有着至关重要的作用。因此，方骨形态的演化可能与取食方式密切相关。然而，现生鸟类方骨形态的多样性长期以来让相关研究变得相当困难。在本研究中，我们整合了现生鸟类所有主要类群以及若干关键的冠群与干群鸟类化石，系统性探讨方骨的形态演化。我们建立了首个以同源性为基础的鸟类方骨系统性解剖图谱，并运用几何形态测量学方法，对方骨的形态变化进行定量分析，从而探索方骨与不同生态类型之间的生态—形态关系，并追踪方骨形态在鸟类演化历史中的变化轨迹。结果显示，取食生态并不能有效预测方骨的形态特征；相反，非生态因素，如体型与系统发育历史，与方骨形态有着更强的关联。我们的分析还显示，冠群鸟类的方骨作为一个高度整合的单元进化，与其相连的邻近骨骼在形态上存在紧密的协同变化。这一发现揭示了方骨形态在鸟类頭颅能動系统中与其他结构协同演化的复杂宏观进化图景。此外，我们的研究强调了在祖先三维形态重建中纳入化石数据的重要性。相比仅使用现生数据的重建，加入化石資料后的祖先方骨形态模型表现出显著的差异。这些基于化石的重建结果为理解冠群鸟类早期取食系统的形态与功能演化提供了新的视角。

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