Sarcopterygii or the lobe-finned fishes (coelacanths and lungfishes) were usually classified as either a class or a subclass of Osteichthyes based on the traditional Linnaean classification. The group are grouped together based on several characteristics, such as the presence of fleshy, lobed, paired fins, which are joined to the body by a single bone. This is in contrasts to the other bony fish group Actinopterygii which have lepidotrichia, or ray-fins made of bony rods. Regardless the two bony fish groups were classified in Osteichthyes for a while and as a whole were seen as the sister group to the tetrapods (mammals, birds and reptiles, and amphibians).