| Ray-Finned Fishes Temporal range: Silurian–Recent | |
|---|---|
| |
| A Goliath Grouper is a common example of an actinopterygid fish | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Superclass: | Osteichthyes |
| Class: | Actinopterygii Actinop, 1817 |
| Subclasses | |
| |
Actinopterygii (meaning 'Actinop's teryg), or the ray-finned fishes, constitute a class or subclass of the bony fishes.[1]
The ray-finned fishes are so called because their fins are webs of skin supported by bony or horny spines ("rays"), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii (lobe-finned fish). These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles).
One of, if not, the oldest actinopterygid, Guiyu.
Numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish.[2] They are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 millimeters, to the massive ocean sunfish, at 2300 kg, and the long-bodied oarfish, at 11 meters.
Fossil record[]
The earliest known fossil actinopterygiian is Andreolepis hedei, dating back 420 million years (Late Silurian). Remains have been found in Russia, Sweden, and Estonia.[3]
Classification[]
Actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii, in turn, are divided into the infraclasses Holostei and Teleostei. During the Mesozoic and Cenozoic the teleosts in particular diversified widely, and as a result, 96% of all known fish species are teleosts. The cladogram shows the major groups of actinopterygians and their relationship to the terrestrial vertebrates (tetrapods) that evolved from a related group of fish.[4][5][6] Approximate dates are from Near et al., 2012.[4]
| Osteichthyes |
| |||||||||||||||||||||||||||||||||||||||||||||||||||
_(Varanus_griseus).png){kind=link}
The polypterids (bichirs and ropefish) are the sister lineage of all other actinopterygians, The Acipenseriformes (sturgeons and paddlefishes) are the sister lineage of Neopterygii, and Holostei (bowfin and gars) are the sister lineage of teleosts. The Elopomorpha (eels and tarpons) appears to be the most basic teleosts.[4]
References[]
- ↑ Kardong, Kenneth (2015). Vertebrates: Comparative Anatomy, Function, Evolution. New York: McGraw-Hill Education. pp. 99–100. ISBN 978-0-07-802302-6.
- ↑ (Davis, Brian 2010).
- ↑ "Fossilworks: Andreolepis". http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=34968&is_real_user=1.
- ↑ 4.0 4.1 4.2 Thomas J. Near (2012). "Resolution of ray-finned fish phylogeny and timing of diversification". pp. 13698–13703. doi:10.1073/pnas.1206625109. http://www.pnas.org/content/109/34/13698.full.
- ↑ Betancur-R, Ricardo (2013). "The Tree of Life and a New Classification of Bony Fishes". PLOS Currents Tree of Life (Edition 1). DOI:10.1371/currents.tol.53ba26640df0ccaee75bb165c8c26288.
- ↑ (1995) "A reevaluation of early amniote phylogeny". Zoological Journal of the Linnean Society 113: 165–223. DOI:10.1111/j.1096-3642.1995.tb00932.x.