Phylogenetic Reconstruction of Lung Evolution in Extant Squamata

ABSTRACT

The Squamata group exhibits remarkable diversity in lung structure. However, a comprehensive understanding of how this variation evolved within the clade is still lacking. To reconstruct the evolutionary history of lungs of living squamates, we conducted comparative phylogenetic analyses using categorized lung traits, such as lung type, respiratory epithelium type, and distribution of parenchyma, obtained from literature‐derived morphological data. Stochastic character mapping on an amniote phylogeny revealed uncertainties regarding the ancestral lung type at the amniote root, whereas strong support for a unicameral lung was found at the base of Lepidosauria, Squamata, Toxicofera, Iguania, and Anguimorpha. Correlation analysis revealed a small but significant association between epithelium type and distribution, suggesting a degree of correlated evolution among these traits.