| Osteichthyes Temporal range: Late Silurian–Present | |
|---|---|
| |
| Guiyu, a primitive member of Osteichthyes. | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Osteichthyes |
| Major subgroups | |
Osteichthyes is a clade of vertebrates commonly referred to as bony fish[Note 1]. Members of the clade are distinguished by the presence of a bony skeleton, whereas other groups of vertebrates, like Chondrichthyans, Placoderms and Acanthodians have cartilaginous skeletons. The vast majority of all vertebrates are housed in this clade.
Description[]
Bony fish are characterized by the presence of a proper set of cranial bones (which fuse in more derived clades to form the cranium). The head and pectoral girdles are bony in all genera, and the rest of the skeleton is ossified in later species.
Classification[]
Osteichthyes is a clade of gnathostomates (jawed fish), sharing the clade with Acanthodians and Chondrichthyans. Bony fish are divided into two main groups: Actinopterygii (ray-finned fish) and Sarcopterygii (lobe-finned fish).
Evolution[]
The first jawed vertebrates evolved in the Ordovician and evolved during the Devonian. The oldest known fossils of Osteichthyes date back to the Silurian period. About 425 million years ago. Contrary to their name, these early fish didn’t yet evolve ossification, making them initially cartilaginous.