Investigation of fundamental areas of vertebrate biology depend critically on a robust phylogeny of fishes, yet evolutionary relationships among the major actinopterygian and sarcopterygian lineages have not been conclusively resolved. Although a consensus phylogeny of teleosts has been emerging recently, it has been based on analyses of various subsets of actinopterygian taxa, but not on a full sample of all bony fishes. Here we conducted a comprehensive phylogenetic study on a broad taxonomic sample of 61 actinopterygian and sarcopterygian lineages with a chondrichthyan outgroup using a molecular data set of 21 independent loci. Relaxed-clock dating analysis employing a set of 24 newly applied fossil calibrations reveals divergence times that are more consistent with paleontological estimates than previous studies. Establishing a new phylogenetic pattern with accurate divergence dates for bony fishes illustrates several areas where the fossil record is incomplete and provides critical new insights on diversification of this important vertebrate group.
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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.
Ray-finned fishes occur in many variant forms. The main features of a typical ray-finned fish are shown in the adjacent diagram. Ray-finned fishes have many different types of scales; but all teleosts , the most advanced actinopterygii, have leptoid scales. The outer part of these scales fan out with bony ridges while the inner part is crossed with fibrous connective tissue. Leptoid scales are thinner and more transparent than other types of scales, and lack the hardened enamel or dentine-like layers found in the scales of many other fish.
Unlike ganoid scales, which are found in non-teleost actinopterygii, new scales are added in concentric layers as the fish grows. Ray-finned fish are very varied in size and shape, and in the number of their ray-fins and the manner in which they arrange them. Tuna are streamlined for straight line speed with a deeply forked tail. The swordfish is even faster and more streamlined than the tuna.
Salmon generate enough thrust with their powerful tail fin to jump obstacles during river migrations. Cod have three dorsal and two anal fins , which give them great maneuverability. Flatfish have developed partially symmetric dorsal and pelvic fins.
Fangtooth are indifferent swimmers who try to ambush their prey. The first spine of the dorsal fin of anglerfish is modified like a fishing rod with a lure. King of herrings. In nearly all ray-finned fish, the sexes are separate, and in most species the females spawn eggs that are fertilized externally, typically with the male inseminating the eggs after they are laid.
Development then proceeds with a free-swimming larval stage. In most cases this involves protogyny , fish starting life as females and converting to males at some stage, triggered by some internal or external factor. Protandry , where a fish converts from male to female, is much less common than protogyny. There are a few examples of fish that self-fertilise.
The mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to the fish's habit of spending long periods out of water in the mangrove forests it inhabits. This maintains genetic variability in a species that is otherwise highly inbred.
The earliest known fossil actinopterygiian is Andreolepis hedei , dating back million years Late Silurian. Remains have been found in Russia , Sweden , and Estonia. Actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii , in turn, are divided into the infraclasses Holostei and Teleostei.
The cladogram shows the major groups of actinopterygians and their relationship to the terrestrial vertebrates tetrapods that evolved from a related group of fish. Coelacanths , Lungfish. Sauropsids reptiles , birds. Polypteriformes bichirs , reedfishes. Acipenseriformes sturgeons , paddlefishes. Lepisosteiformes gars. Amiiformes bowfins. The polypterids bichirs and reedfish 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 appear to be the most basal teleosts. From Wikipedia, the free encyclopedia. Class of fishes. Anatomy of a typical ray-finned fish cichlid. Further information: Fish fin. Elongated bristlemouth. European conger are ray-finned fish. See also: Evolution of fish. Blue catfish skeleton.
Vertebrates: Comparative Anatomy, Function, Evolution. Saunders College Publishing. Sexual Development. The Behavior of Teleost Fishes. Goodwin; Robert P. Freckleton 19 March The Evolution of Parental Care. Gross; Richard Shine Journal of Theoretical Biology. Retrieved 15 September Environmental Biology of Fishes.
Reproductive Biology of Teleost Fishes. Archived from the original on 12 February Retrieved 14 May Near; et al. Bibcode : PNAS.. Archived from the original on 11 April Retrieved 11 April Archived from the original on 13 October Zoological Journal of the Linnean Society. Archived from the original on 25 December Hopkins; Arthur N. Popper BMC Evolutionary Biology.
Fishes of the World. Integrated Taxonomic Information System. Retrieved 3 April Froese and D. Pauly, editors February Archived from the original on 5 July Retrieved 8 January Family-group names of fossil fishes. Extant Actinopterygii orders by subclass. Lepisosteiformes Amiiformes. Elopiformes Albuliformes Notacanthiformes Anguilliformes.
Osteoglossiformes Hiodontiformes. Argentiniformes Galaxiiformes Salmoniformes Esociformes. Osmeriformes Stomiiformes. Ateleopodiformes Aulopiformes Myctophiformes Lampriformes Polymixiiformes. Percopsiformes Zeiformes Stylephoriformes Gadiformes. Extant chordate classes. Kingdom Animalia unranked Bilateria Superphylum Deuterostomia. Leptocardii lancelets. Ascidiacea sea squirts Appendicularia larvaceans Thaliacea pyrosomes, salps, doliolids.
Myxini hagfish Hyperoartia lampreys. Chondrichthyes cartilaginous fish: sharks, rays, chimaeras. Actinopterygii ray-finned fish. Amphibia amphibians. Mammalia mammals. Evolution of fish. Evolutionary biology portal.
Elasmobranchii Holocephali. Lists of prehistoric fish spiny sharks placoderms cartilaginous bony lobe-finned List of transitional fossils.
Osteichthyes and Actinopterygii John Merck Link to cladogram and phylogram cheat-sheets. Definition: The last common ancestor of Actinopterygii ray-finned fish and Sarcopterygii lobe-finned fish. Osteichthyan Trends:. Osteichthyes weren't the first vertebrates with bone, but they developed and used it in novel ways that cause their skeletons to preserve much more evolutionary information: Major trends: Widespread endochondral bone in the braincase and postcranial skeleton. Emergence of recognizable dermal elements of the head and pectoral girdle.
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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. Ray-finned fishes occur in many variant forms. The main features of a typical ray-finned fish are shown in the adjacent diagram. Ray-finned fishes have many different types of scales; but all teleosts , the most advanced actinopterygii, have leptoid scales.
Herpetichthyes, Amphibioidei, Choanichthyes or Sarcopterygii?
A strict cladistic view shows that some Sarcopterygii evolved into the tetrapods , a superclass including amphibians , reptiles including dinosaurs and therefore birds , and mammals. The living non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfish. Early lobe-finned fishes are bony fish with fleshy, lobed, paired fins , which are joined to the body by a single bone. The scales of sarcopterygians are true scaloids , consisting of lamellar bone surrounded by layers of vascular bone, dentine -like cosmine , and external keratin. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. These fins evolved into the legs of the first tetrapod land vertebrates, amphibians.