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Evolution of birds from feathered reptiles
Birds, in the sense of flying descendants of feathered reptiles (a more expansive group than the "true" birds in today's skies), evolved several times from within the theropods.
Crustacean-trapping teeth in mesosaurs and crabeater seals
The multi-lobed post-canines of Lobodon carcinophagus are a functional analogue to the long, thin cage-like teeth of Mesosaurus, as both cage and prevent the escape of small crustacean prey.
Teeth in aquatic reptiles
Aquatic reptiles tend to display one of three dentition types, well adapted to either seize and slice large vertebrate prey, pierce and gouge slippery fish, or entrap small prey such as crustaceans.
Teiid lizard dentition: convergence with other reptiles, mammals and fish
Teiids are skink-like lizards whose members show a stunning diversity of tooth types, providing rich evidence of convergence within the teiids themselves, in distantly related reptile groups and even in certain mammals and fish.
Complex tooth occlusion in notosuchid crocodiles and tritylodonts (proto-mammals)
Two unusual Early Cretaceous crocodiles provide a shining example of convergence, as their dentition parallels that observed in a group of advanced proto-mammals called tritylodonts.
Reptile dentition: convergence on complex occlusion
Some reptiles have transverse chisel-like teeth for slicing, and others have teeth bearing projections ('cusps') that interlock and slice or grind tough food. In each case evolutionary parallels are clear both within and outside the reptiles.
Beak structures in reptiles and birds
Among reptile taxa with beak structures, we find several cases of convergent evolution, for example between turtles, Uromastyx lizards, a number of herbivorous dinosaurs and the tuatara (Sphenodon) of New Zealand.
Venom and venom fangs in snakes, lizards and synapsids
Although the evolution of snake fangs itself provides us with a window on convergence, the presence of fang-like teeth in lizards, therapsids and mammals provides an even broader and more remarkable perspective.
Gliding in feathered reptiles
A number of reptile species have been discovered in the Mesozoic fossil record, bearing feathers that were apparently used to support gliding locomotion, rather than true, powered flight as we see in present day birds.
In the reptiles, different forms of skin membrane (called ‘patagia’) and in some extinct species, primitive feathers, have evolved convergently as adaptations for gliding.
Ancient opsins and vision in extinct animals
Spectral tuning of the eye generally depends on key substitutions of amino acid sites in opsin proteins.