Lawson Adam B, Martinez Aracely, Hedrick Brandon P, Echols M Scott, Schachner Emma R
Department of Structural & Cell Biology, Tulane University School of Medicine, New Orleans, Louisiana, USA.
Department of Cell Biology and Anatomy, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
J Anat. 2025 Jan;246(1):1-19. doi: 10.1111/joa.14146. Epub 2024 Oct 7.
The anatomy of the avian lower respiratory system includes a complex interaction between air-filled pulmonary tissues, pulmonary air sacs, and much of the postcranial skeleton. Hypotheses related to the function and phylogenetic provenance of these respiratory structures have been posed based on extensive interspecific descriptions for an array of taxa. By contrast, intraspecific descriptions of anatomical variation for these features are much more limited, particularly for skeletal pneumatization, and are essential to establish a baseline for evaluating interspecific variation. To address this issue, we collected micro-computed tomography (μCT) scans of live and deceased African grey parrots (Psittacus erithacus) to assess variation in the arrangement of the lungs, the air sacs, and their respective invasion of the postcranial skeleton via pneumatic foramina. Analysis reveals that the two pairs of caudalmost air sacs vary in size and arrangement, often exhibiting an asymmetric morphology. Further, locations of the pneumatic foramina are more variable for midline, non-costal skeletal elements when compared to other pneumatized bones. These findings indicate a need to better understand contributing factors to variation in avian postcranial respiratory anatomy that can inform future intraspecific and interspecific comparisons.
鸟类下呼吸系统的解剖结构包括充满空气的肺组织、肺气囊以及大部分颅后骨骼之间的复杂相互作用。基于对一系列分类群的广泛种间描述,已经提出了与这些呼吸结构的功能和系统发育起源相关的假说。相比之下,关于这些特征的解剖变异的种内描述则更为有限,尤其是骨骼的气腔化,而这对于建立评估种间变异的基线至关重要。为了解决这个问题,我们收集了活体和死亡的非洲灰鹦鹉(Psittacus erithacus)的微型计算机断层扫描(μCT)图像,以评估肺、气囊的排列变化,以及它们通过气腔孔对颅后骨骼的各自侵入情况。分析表明,两对最尾端的气囊在大小和排列上存在差异,常常呈现出不对称的形态。此外,与其他气腔化骨骼相比,中线非肋骨骨骼元素的气腔孔位置变化更大。这些发现表明,需要更好地了解导致鸟类颅后呼吸解剖结构变异的因素,以便为未来的种内和种间比较提供参考。