Supplementary Dataset Folder - Evolution of Endothermy in Marine Vertebrates

Endothermy, metabolic heat production, has independently arisen in several vertebrate lineages. However, endothermy is rare among the approximately 36,000 known fish species. Our study investigates its evolutionary roots in marine environments by analyzing phylogenomic data from 1,051 ray-finned fish species, ecological and morphological traits, and genomes of 205 marine vertebrates. Using a novel time-dependent threshold model, we reveal a correlation between endothermy, body length, swim mode, and cetacean diversification during the Eocene-Oligocene, suggesting endothermy in ray-finned fishes evolved from competition with emerging cetaceans, promoting faster swimming. Additionally, we found 32 genes showing convergent evolution related to metabolism, muscle function, and neural responses in endothermic marine vertebrates. These findings challenge long-standing hypotheses, offering new insights into the adaptations essential for endothermy’s evolution in the ocean.