Actinopterygii or the ray-finned fishes, constitute a class or subclass of the bony fishes. 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). A – dorsal fin: B – fin rays: C – lateral line: D – kidney: E – swim bladder. Class Actinopterygii and Class Sarcopterygii. FishBase World Wide Web electronic publication. Accessed August 16, at http://www. Definition: The last common ancestor of Actinopterygii (ray-finned fish) and Sarcopterygii (lobe-finned fish). Osteichthyan Trends: Osteichthyes weren’t the first.
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Fishes — Overview B. First two branchial arches articulate to a single basibranchial.
Chang M-m, Liu Y-h, G. The notochord is not ossified Neural arches protect the nerve cord dorsal to the notochord Ribs may project from the notochord in the trunk region Haemal arches protect blood vessels ventral to the notochord Supraneurals may extend from the neural arches Occasionally, intercalary ossifications actinpterygii “intercalaries” – not shown form between neural or haemal arches.
For all other nodes, the use of different data partition schemes or exclusion of 3rd codon positions had negligible effects. It’s most interesting feature, however, may sarcooterygii its plesiomorphies, including: A thorough survey goes beyond the technical limitations of this course. Morphologically, lepistosteids occupy the end of a long branch encompassing much unique evolutionary change.
A new opercular element, the interopercular iop served to close the gap between the opercular series and jaw. Resulting topologies were compared to each other and to that obtained from a concatenated unpartitioned data set.
Three major teleost stem lineages, Elopomorpha, Osteoglossomorpha and Clupeocephala, then arose rapidly in the Middle Permian. Instead, it is lined by robust fulcral scales.
Introduction The evolutionary history of bony vertebrates remains an outstanding problem in the Tree of Life. The scales of sarcopterygians are true scaloidsconsisting of actinlpterygii bone surrounded by layers of vascular bone, dentine -like cosmineand external keratin. Arratia G The caudal skeleton of Jurassic sarcopterggii a phylogenetic analysis. Our estimate of Ma for divergence of crown Osteichthyes places the origin of Sarcopterygii and Actinopterygii in the Middle Silurian, with the sarcopterygian crown group evolving in the Early Devonian Ma and the actinopterygian crown group evolving at the Middle-Late boundary of the Devonian Ma.
The small jaws are hyostylic.
Ascidiacea sea squirts Appendicularia larvaceans Thaliacea pyrosomes, salps, doliolids. Palaeo Ichthyologica 7 Most analyses Xu et al. Pre- and postaxial elements branch from a metapterygial axis. West Indian Ocean coelacanth.
Hyoid arch cartilages ossify as: Science China Actinoptergyii Sciences 53 12 Vaguely like a sturgeon trying to be a barracuda. This appears to be another case where short times separating divergence events result in reduced phylogenetic signal. Among these, species richness is highly skewed with only 18 living species of Polypteriformes reedfishes30 species of sturgeons and paddlefishes Acipenseriformes7 species of gars Lepisosteiformesand a single species of bowfin Amiiformesrelative to at least 30, living species of teleosts Most morphological characters may thus xarcopterygii arisen outside the diversification window and be ancestral to many lineages symplesiomorphies or derived but unique to single descendant lineages autapomorphies.
Long JA A new rhizodontiform fish from the Early Carboniferous of Victoria, Australia, with remarks on the phylogenetic position of the group. Moythomasia nitida Actinpoterygii and Strunius sp. The present molecular date for crown neopterygians of Ma is surprisingly similar to the Ma estimate of Hurley et al. Actinnopterygii C, Rosen DE Review of ichthyodectiform and other Mesozoic teleost fishes and the theory and practice of classifying fossils.
The identity of the living sister group to Tetrapodomorpha has been controversial since the discovery of a living coelacanth in The ancestral osteichthyan had ossified neural and haemal arches, but the notochord remained unossified. Cosmoid scales Typically lack ganoine although the most basal members have it.
Comparative Anatomy, Achinopterygii, Evolution. Dialipina markae from Adventure Canada. Actinoopterygii early PaleoceneChina.
Development then proceeds with a free-swimming larval stage. Consequently, with the exception of teleosts and tetrapods, the pattern of vertebrate phylogeny close to the base of the tree is one of very long phyletic branches that lack intervening divergences leading to actinopterygki descendants.
In these notes, I place such names in “quotation marks. Living chondrosteans significantly reduce their amount of endochondral ossification.
However, sarcopterygian relationships are notoriously contentious 15 16 17 18 and much of the current view of ray-finned fish evolution remains based on morphological studies conducted nearly four decades ago 19 20 In Sarcopterygian lineages of Paleozoic age, a converse situation exists where fossil taxa e.
Myxini hagfish Hyperoartia lampreys. The Tetrapodomorpha contain the crown group tetrapods the last common ancestor of living tetrapods and all of its descendants and several groups of early stem tetrapodsswrcopterygii several groups of related lobe-finned fishes, collectively known as the osteolepiforms. The new result eliminates this problem and places the minimum divergence age of crown Actinopterygii in the Early Triassic.
We therefore focused analyses on the concatenated dataset of all 21 genes.
American Journal of Sciences The Evolution of Parental Care. Named the preopercular pop in actinopterygians, and arguably homologous to the preopercular and squamosal in srcopterygians Median elements: A similar classification was proposed by Wiley and Johnson 25 based on a actinopterygi of morphological synapormorphies from the literature.
Combined selection of partitioning schemes and substitution models for phylogenetic analyses. Therefore, it appears that diversification of the major teleost lineages is closely associated with amelioration of the restrictive environmental conditions resulting from Late Permian events.
The time tree for bony fishes is shown in Figure 2.