What did the brains of the first land vertebrates look like?
By Mischa Dijkstra, Frontiers science writer / Dr Alice M Clement, Flinders University Dr Alice Clement. Image: Flinders University What did the brain of the early tetrapodomorphs, the first fish to develop limbs and walk on land, look like? Preserved brains are very rare in fossils, and even when preserved they were typically shrunken and deformed before becoming fossilized. For this reason, researchers mostly rely on casts of the cranial vault of fossils to study the early evolution of the brain. The closest living relatives of tetrapodomorphs, coelacanths, are known to have brains that are tiny compared to the braincase (1% of volume), so for them endocasts don’t give much information about brain morphology. But are coelacanths representative of extinct tetrapodomorphs in that regard? In a new study in Frontiers in Ecology and Evolution, Clement et al. show that this is likely not the case: among living amphibia – together with lungfish, the next closest living relatives of tetrapodomorphs – 4 basal species of frogs and caecilians have brains with a volume of 49-78% of the braincase. Their brains are somewhat larger relative to the braincase than those of lungfish, newts, and salamanders (38-47%), and the authors suggest that the […]