Lipids in the American Alligator stratum corneum provide insights into the evolution of vertebrate skin.

In terrestrial vertebrates, the outermost layer of the skin, the stratum corneum (SC), provides a durable and flexible interface with the environment and is comprised of corneocytes embedded in lipids. However, the morphology and lipid composition of the SC varies throughout evolutionary history. Because crocodilians and birds phylogenetically bracket the Archosaurian clade, lipid composition in crocodilian SC may be compared with that of birds and other vertebrates to make inferences about broader phylogenetic patterns within Archosaurs while highlighting adaptations in vertebrate skin.