2005/03/01 by Robert L. Carroll, Jason T. Irwin, David M. Green · 2 citations
Earth and Planetary Sciences · Environmental Science · #Paleontology and Evolutionary Biology #Amphibian and Reptile Biology #Evolution and Paleontology Studies #Biology #Devonian #Carboniferous #Late Devonian extinction #Paleontology #Paleozoic #Lungfish #Thermoregulation #Tetrapod (structure) #Zoology #Anatomy #Fish <Actinopterygii> #Ecology #Fishery
paper · pdf · doi:10.1111/j.1096-3642.2005.00151.x
openalex publication_date 2005/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
The adaptive reasons for the evolutionary transition between obligatorily aquatic lobe-finned fish and facultatively terrestrial early tetrapods have long been debated. The oldest adequately known amphibians, Acanthostega and Ichthyostega, from the final stage in the Upper Devonian (Famennian), can be clearly distinguished from the most advanced choanate sarcopterygian fish from the next older stage (Frasnian) by the presence of large pectoral and pelvic girdles, limbs generally resembling those of later Palaeozoic land vertebrates, and the absence of bones linking the back of the skull with the shoulder girdle. Upper Devonian and most Lower Carboniferous amphibians, like their aquatic predecessors, differed significantly from modern amphibians in their much larger size, up to a metre or more in length. Animals of this size, resembling modern crocodiles and the marine iguana, could have raised their body temperatures by basking in the sun and sustained them upon re-entry into the water. It is hypothesized that the physiological advantages of thermoregulation were a major selective force that resulted in the increasing capacity for the ancestors of tetrapods to move into shallow water, and later to support their bodies against the force of gravity and increase the size and locomotor capacities of the limbs.