Ichthyostega is an early tetrapod that lived at the end of the Upper Devonian. It was a labyrinthodont, one of the first tetrapods in the fossil record. As with other tetrapods, ichthyostega possessed a mix of fish-like features (its head and the fin on its tail) and traits found in later amphibians including webbed feet and, presumably, the ability to breathe air for a short period of time. It represented an intermediate form between fish and amphibians. While it had lungs and limbs that allowed it to navigate through the shallow waters of swamps and had an amphibian build and life habits, with its fish-like tail and gills, it was not considered a true amphibian and spent most of its time underwater; true amphibians evolved in the Carboniferous Period. It was a fairly large animal. It averaged about 5 feet (1.5 m) in length with a broad body. The skull was flat with eyes located toward the back of the skull and possessed labyrinthodont type teeth.
Ichthyostega, tetrapod, labyrinthodont