∞ generated and posted on 2016.11.06 ∞
Terrestrial vertebrate animals making up essentially all of the vertebrates other than the fish.
Tetrapods are called tetrapods because they have four limbs that in most cases are legs (the exceptions include our arms, bird as well as bat wings, the flippers of seals and whales, and also the absence of legs in, for example, snakes).
Though the number of digits (fingers and toes) per limb differed among various lobe-finned fish, tetrapods tend to possess either five digits or instead a reduced number of digits (e.g., horses).
Among extant vertebrates the tetrapods include the amphibians, the reptiles, the birds, and the mammals. Extinct dinosaurs also were tetrapods. The most primitive of tetrapods resembled lobe-finned fish (see, e.g., fishapod).