To K H T, O'Brien H D, Stocker M R, Gignac P M
Department of Geosciences, Virginia Tech, Derring Hall, 926 W Campus Dr, Blacksburg, VA 24060, USA.
Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 W 17th Street, Tulsa, OK 74107, USA.
Integr Org Biol. 2021 Apr 30;3(1):obab007. doi: 10.1093/iob/obab007. eCollection 2021.
Synopsis Dietary requirements and acquisition strategies change throughout ontogeny across various clades of tetrapods, including birds. For example, birds hatch with combinations of various behavioral, physiological, and morphological factors that place them on an altricial-precocial spectrum. Passeriformes (=songbirds) in particular, a family constituting approximately more than half of known bird species, displays the most drastic difference between hatchling and adults in each of these aspects of their feeding biology. How the shift in dietary resource acquisition is managed during ontogeny alongside its relationship to the morphology of the feeding apparatus has been largely understudied within birds. Such efforts have been hampered partly due to the small size of many birds and the diminutive jaw musculature they employ. In this study, we used standard and diffusible iodine-based contrast-enhanced computed tomography in conjunction with digital dissection to quantify and describe the cranial musculature of the Black-throated Finch () at fledgling and adult stages. Our results reveal that in both the fledgling and the adult, cranial musculature shows clear and complex partitioning in the that is consistent with other families within Passeriformes. We quantified jaw-muscle sizes and found that the adult showed a decrease in muscle mass in comparison to the fledgling individual. We propose that this could be the result of low sample size or a physiological effect of parental care in Passeriformes. Our study shows that high-resolution visualization techniques are informative at revealing morphological discrepancies for studies that involve small specimens such as Passeriformes especially with careful specimen selection criteria.
包括鸟类在内的四足动物不同进化枝在个体发育过程中，其饮食需求和获取策略会发生变化。例如，鸟类孵化时具有各种行为、生理和形态学因素的组合，这些因素使它们处于晚成雏 - 早成雏的范围内。特别是雀形目（=鸣禽），这一鸟类家族约占已知鸟类物种的一半以上，在其取食生物学的这些方面，雏鸟和成鸟之间表现出最显著的差异。在鸟类个体发育过程中，饮食资源获取的转变是如何管理的，以及它与取食器官形态的关系，在很大程度上尚未得到充分研究。这种研究受到部分阻碍是由于许多鸟类体型小以及它们所使用的下颌肌肉组织微小。在本研究中，我们使用标准的和基于可扩散碘的对比增强计算机断层扫描结合数字解剖，来量化和描述黑喉草雀（）雏鸟和成鸟阶段的颅骨肌肉组织。我们的结果表明，在雏鸟和成鸟中，颅骨肌肉组织在[此处原文缺失具体部位信息]都呈现出清晰且复杂的分区，这与雀形目内的其他家族一致。我们量化了颌部肌肉大小，发现成鸟与雏鸟个体相比肌肉质量有所下降。我们认为这可能是样本量小或雀形目亲代抚育的生理效应导致的结果。我们的研究表明，高分辨率可视化技术对于揭示涉及小型标本（如雀形目）的形态差异具有重要意义，尤其是在有仔细的标本选择标准的情况下。
