Temporal range: Jurassic–Recent
|Spotted gar, Lepisosteus oculatus|
|Bowfin, Amia calva|
Holostei are bony fish that retain characteristics from an early time in evolution. There are eight species divided among two orders, the Amiiformes represented by a single living species, the bowfin (Amia calva), and the Lepisosteiformes, the gars. There are more species to be found in the fossil record.
Holostei share with other non-teleost ray-finned fish a mixture of characteristics of teleosts and sharks. In comparison with the other group of non-teleost ray-finned fish, the chondrosteans, the Holostei are closer to the teleosts and further from sharks: the pair of spiracle found in sharks and chondrosteans is reduced to a remnant structure (in gars, the spiracles does not open to the outside); the skeleton is ossified (a thin layer of bone covers a mostly cartilaginous skeleton in the bowfins). In gars, the tail is still heterocercal but less so than in the chondrosteans; bowfins have many rayed dorsal fins and can breathe air like the bichirs.
The Holostei is often regarded as paraphyletic; as a result this infraclass is often not used, the two orders contained in it being often treated simply as members of the sub-class Neopterygii without any taxonomic association. However, recent work mitochondrial analysis of DNA seems to support its recognition, so the question is not yet resolved. Nearly all living bony fishes are teleosts.
The name derives from the Greek, holos meaning whole and osso (osteo) meaning bone: a reference to their bony skeletons.
- Ontario. Game and fish commission
- Rick Leah. "Holostei". University of Liverpool (http://www.liv.ac.uk).
- "Holostei". Integrated Taxonomic Information System. Retrieved 30 June 2006.