Description
Sarcopterygii (; from Ancient Greek __ σάρξ (sárx) 'flesh', and __ πτέρυξ (ptérux) 'wing, fins') — sometimes considered synonymous with Crossopterygii (from Ancient Greek __ κροσσός (krossós) 'fringe') — is a taxon (traditionally a class or subclass) of the bony fish known as the lobe-finned fish or sarcopterygians , characterised by prominent muscular buds (lobes) within the fins. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only bony spines supporting the fins.
The group Tetrapoda, a mostly terrestrial superclass of limbed vertebrates including amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (with mammals being the only extant group), evolved from sarcopterygian ancestors; under a cladistic view, tetrapods are themselves considered a subgroup (or rather, the dominant crown group) within Sarcopterygii.
The known extant non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfishes.
