Tetrapods (Greek τετραποδη tetrapoda, Latin quadruped, "four-footed") are vertebrate animals having four feet, legs or leglike appendages. Amphibians, reptiles, dinosaurs/birds, and mammals are all tetrapods, and even the limbless snakes are tetrapods by descent. The earliest tetrapods radiated from the Sarcopterygii, or lobe-finned fish.
Research by Jennifer A. Clack and her colleagues showed that the earliest tetrapods, such as Acanthostega, we...
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Tetrapods (Greek τετραποδη tetrapoda, Latin quadruped, "four-footed") are vertebrate animals having four feet, legs or leglike appendages. Amphibians, reptiles, dinosaurs/birds, and mammals are all tetrapods, and even the limbless snakes are tetrapods by descent. The earliest tetrapods radiated from the Sarcopterygii, or lobe-finned fish.
Research by Jennifer A. Clack and her colleagues showed that the earliest tetrapods, such as Acanthostega, were wholly aquatic and quite unsuited to life on land. This overturned the earlier view that fish had first invaded the land — either in search of prey (like modern mudskippers) or to find water when the pond they lived in dried out — and later evolved legs, lungs, etc.
The first tetrapods are now thought to have evolved in shallow and swampy freshwater habitats, towards the end of the Devonian, a little more than 365 million years ago. By the late Devonian, land plants had stabilized freshwater habitats, allowing the first wetland ecosystems...
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