Temporal range: Jurassic–Recent
|Spotted gar, Lepisosteus oculatus|
|Bowfin, Amia calva|
Holostei are bony fish that retain basal characteristics inherited from an early time in their 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 spiracles found in sharks and chondrosteans is reduced in holosteans to a remnant structure: in gars, the spiracles do not even open to the outside; the skeleton is lightly 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 treated instead simply as members of the sub-class Neopterygii without any further taxonomic ranking. However, in recent work mitochondrial analysis of DNA seems to support the recognition of Holostei aas a clade, so the question is not yet resolved. Nearly all living bony fishes are teleosts.
The name Holostei 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.