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The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
Tulerpeton is considered one of the first "tetrapods" (in the broad sense of the word) to have evolved.It is known from a fragmented skull, the left side of the pectoral girdle, and the entire right forelimb and right hindlimb along with a few belly scales.
The kids finally get into Starfleet Academy, only to have the attack on Mars [f] drastically change things. Returning to Starfleet in the wake of the attack, Janeway has the new Protostar-class vessel, the USS Prodigy, turned into a training ship and gives it to the former Protostar crew along with field commissions to the rank of ensign.
That fish and its friends eventually evolved into a plethora of species that belong to a group collectively known as tetrapods, which encompasses all four-limbed vertebrate creatures that roam the ...
The tongue is anchored to the hyoid bone, which was once the lower half of a pair of gill bars (the second pair after the ones that evolved into jaws). [89] [90] [91] The tongue did not evolve until the gills began to disappear. Acanthostega still had gills, so this would have been a later development. In an aquatically feeding animals, the ...
The creature existed some 40 million years before dinosaurs evolved. Researchers have long examined such ancient predators to uncover the origins of tetrapods: four-legged animals that clambered ...
Limbs in vertebrates are occasionally organized into stylopod (relating to the humerus and femur), zeugopod (relating to the radius and tibia, along with associated structures) and autopod (relating to digits) categories, although anatomically, the evolutionary differences between these groups in early tetrapods tends to be vague. [2] [20]
New animals appeared in the warmer, drier regions near the equator as four-legged vertebrates called stem tetrapods evolved and split into groups that formed the basis for modern animals.