Remarks on the Evolution of Integumental Scale Armor

The document discussed the evolution of integumental scale armor, focusing on pangolins, which have large, hardened scales made of α-keratins and β-keratins that provide high abrasive wear resistance. These scales, soft at birth and hardening with age, serve as armor when the animal curls up, offering defense with their sharp edges. The study highlighted the water-to-land transition in tetrapods, which led to a significant diversification of keratin genes, contributing to the development of rigid integumental structures and further keratin diversification in tetrapod lineages.