The tetra pods - back boned animals with four limbs, including amphibians, reptiles, birds
and mammals - almost certainly evolved from some form of Devonian lobe-finned fish or
sarcopterygian. This would have possessed the same pattern of bones in its fin bases as .
found in limbs of terrestrial vertebrates. Osteolepis was a relative of such a fish. This is not
only because of the srrucruralsirnilarity between its fin bones anda tetrapod's limb bones,
but also because of other features found in -the first amphibian-type tetrapods. These include
an internal link between the nose and throat, termed the choanae, which most fish lack, but
all tetra pods have. Osteolepis lived in shallow bodies of fresh water, feeding on any prey it
could find, and was able to breathe air as well as obtaining oxygen through its gills