Biological variables are frequently described by analyzing scaling relationships of the variable against body mass (M_B). Respiratory variables are no exception and allometric relations for oxygen consumption, pulmonary ventilation, tidal volume, breathing frequency, and lung volume have been described in the literature. While the allometric relations of respiratory variables given for mammals and birds are very consistent among different studies, scaling relationships for non-avian reptiles have only been scarcely described and show considerable variation between studies. Since no comprehensive study of allometric relations of respiratory variables has been carried out comparing the different groups of non-avian reptiles, we analyzed morphological and physiological variables of the respiratory system of crocodilians, chelonians, lizards, snakes, birds, and mammals, regarding the allometric relations of each variable from a phylogenetic perspective as well as related to lung morphology. Our results indicated that few respiratory variables possess significant phylogenetic signals and that tidal volume, breathing frequency (except mammals), and air convection requirement were independent of phylogeny. Contrary to the literature, lung volume of amniotes scaled isometrically to M_B, with the exception of lizards (M_B^0.78). Air convection requirement scaled isometrically in mammals and birds, but was more variable among non-avian reptiles, from a taxonomic perspective and in regard to different lung structures. In conclusion, respiratory variables among non-avian reptiles scaled more variably than previously expected, both according to phylogeny and to lung type, warranting future studies to explore structure-function relations of the reptilian respiratory system, especially regarding snakes and crocodilians, since these groups had very few data available for analysis.

通常通过分析变量与体重的比例关系来描述生物变量（M _B）。呼吸变量也不例外，有关耗氧量，肺通气量，潮气量，呼吸频率和肺活量的异速关系已经在文献中进行了描述。尽管在不同的研究中为哺乳动物和鸟类提供的呼吸变量的异形关系非常一致，但很少描述非禽类爬行动物的比例关系，并且在研究之间显示出相当大的差异。由于尚未对不同类别的非禽类爬行动物进行呼吸变量异速关系的全面研究，因此我们分析了鳄鱼，龟，蜥蜴，蛇，鸟和哺乳动物呼吸系统的形态和生理变量，从系统发育角度以及与肺形态有关的每个变量的异形关系。我们的结果表明，很少有呼吸变量具有重要的系统发育信号，并且潮气量，呼吸频率（哺乳动物除外）和对流需求与系统发育无关。与文献相反，羊水的肺容积等轴测成M_B，蜥蜴除外（M _B ^0.78）。空气对流需求在哺乳动物和鸟类中等距缩放，但从分类学的角度以及就不同的肺部结构而言，在非禽类爬行动物中变化更大。总之，根据系统发育和肺类型，非禽类爬行动物之间的呼吸变量比以前预期的变化更大，因此有必要进一步研究爬行动物呼吸系统的结构-功能关系，特别是关于蛇和鳄鱼，因为这些人群几乎没有可用于分析的数据。