School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PT, UK
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.
J Exp Biol. 2019 Dec 10;222(Pt 23):jeb209783. doi: 10.1242/jeb.209783.
The avian ribcage is derived relative to other amniotes, and is hypothesised to be constrained in its movements during ventilation. The double-headed ribs form two articulations with the vertebrae, and are thought to rotate about a strict anatomical axis. However, this costovertebral joint constraint has not been demonstrated empirically and was not found in other taxa with double-headed ribs (i.e. crocodilians). Here, we used X-ray reconstruction of moving morphology (XROMM) to quantify rib rotation in wild turkeys () during breathing. We demonstrate that, as predicted from anatomy, the ribs do rotate in a hinge-like manner about a single axis. There is also evidence for elliptical motion of the sternum, as has been reported in other taxa. The evolution of the avian ribcage is closely related to the co-evolution of ventilation and flight, and these results are important for how we model ventilation mechanics in living and fossil birds.
禽类的胸廓相对于其他羊膜动物是衍生的，并且在通气过程中其运动被认为是受到限制的。双头肋骨与脊椎形成两个关节，并被认为是围绕一个严格的解剖学轴旋转。然而，这种肋椎关节的限制尚未得到经验证明，在具有双头肋骨的其他类群（即鳄鱼）中也没有发现。在这里，我们使用运动形态的 X 射线重建（XROMM）来量化野生火鸡（）呼吸过程中的肋骨旋转。我们证明，正如解剖学所预测的那样，肋骨确实是围绕单个轴以铰链的方式旋转。胸骨也有椭圆形运动的证据，这在其他类群中也有报道。鸟类胸廓的进化与通气和飞行的共同进化密切相关，这些结果对于我们如何在活体和化石鸟类中模拟通气力学非常重要。
