Sarcopterygii
Sarcopterygii (/ˌsɑːrkɒptəˈrɪdʒi.aɪ/; from Ancient Greek σάρξ (sárx) 'flesh', and πτέρυξ (ptérux) 'wing, fin') — 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 limb buds (lobes) within the fins, which are supported by articulated appendicular skeletons. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only skin-covered bony spines (lepidotrichia) supporting the fins.
| Lobe-finned fishes | |
|---|---|
| From top to bottom and left to right, examples of sarcopterygians: Guiyu oneiros, West Indian Ocean coelacanth, Australian lungfish and the tetrapodomorph Panderichthys rhombolepis. | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Superclass: | Osteichthyes |
| Clade: | Sarcopterygii Romer, 1955 |
| Subgroups | |
| |
The group Tetrapoda, a mostly terrestrial superclass of limbed vertebrates including amphibians, sauropsids (reptiles, including birds and other dinosaurs) and synapsids (mammals and their ancestors), evolved from sarcopterygian ancestors; under a cladistic view, tetrapods are themselves considered a subgroup (or rather, the dominant crown group) within Sarcopterygii.
Non-tetrapod sarcopterygians were once the dominant predators of freshwater ecosystems during the Carboniferous and Permian periods, but suffered significant decline after the Great Dying. Known extant non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfishes.