kidzsearch.com > wiki Explore:web images videos games
Temporal range: Devonian–Recent
Holocephali ("complete heads") is a subclass of cartilaginous fish, of which the order Chimaeriformes is the only surviving group. Holocephali has an extensive fossil record that starts during the Devonian period. However, most fossils are teeth, and the body forms of numerous species are not known, or, at best, poorly understood.