extinct genus of lobe-finned fishes from the Late Devonian; Osteolepiformes is a variation of this name that was given to a group of vertebrates that contained the closest relatives of the tetrapods. Osteolepis survived into later Devonian time. (The Devonian Period lasted from 416 million to 359 million years ago.) Its body was covered with large rhomboid scales; the upper lobe of the tail was more strongly developed than the lower lobe. The general bone pattern in the skull and jaws closely resembles that of the first tetrapods.