Phlegethontia set itself apart from the amphibian pack not only with its lack of limbs, but with its unusual, lightweight skull, similar to those of modern snakes (and most likely explained by convergent evolution).
Fish Out of Water - The First TetrapodsPrehistoric Amphibians - The Story of Amphibian EvolutionBefore the Dinosaurs - Pelycosaurs, Archosaurs and Therapsids
How Dinosaurs EvolvedHow Dinosaurs Are ClassifiedDinosaurs and Creationists
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