2025/09/30 by Jackson R. Phillips, Pedro Henrique dos Santos Dias, Molly C. Womack · 1 voice
Environmental Science · Agricultural and Biological Sciences · #Amphibian and Reptile Biology #Physiological and biochemical adaptations #Bat Biology and Ecology Studies
paper · doi:10.1093/evolut/qpaf192
openalex publication_date 2025/09/30 · openalex created_date 2025/10/28 · openalex updated_date 2026/07/28
The environmental factors associated with adaptive trait loss and the extent to which lost traits can be regained have been subject to much speculation and debate in evolutionary biology. We use tadpole lungs to test if previously proposed environmental factors, such as a stream habitat, are associated with larval lung loss and whether lungs can be regained following loss. We assembled a dataset of lung presence for the larvae of 529 anurans, finding 28 instances of larval lung loss, and develop a methodological framework to test the evolutionary associations between lung loss, general habitat type, terrestriality, and stream specialization, finding strong support for the final 2 factors in adaptive lung loss. The likelihood of regain is thought to depend on whether developmental pathways are preserved over time; accordingly, we predicted larval lung loss to be highly reversible. And yet, we found that larval lungs were never regained, despite lungless tadpoles evolving to live in habitats that favor lung use and all lungless tadpoles developing into lunged frogs. Traditional explanations of irreversibility do not easily explain why stage-specific trait loss would be irreversible, prompting us to examine alternative explanations for natural patterns of irreversibility observed across the tree of life.