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Actinopterygii

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Lauren Sallan – 1st expert on this subject based on the ideXlab platform

  • major issues in the origins of ray finned fish Actinopterygii biodiversity
    Biological Reviews, 2014
    Co-Authors: Lauren Sallan

    Abstract:

    : Ray-finned fishes (Actinopterygii) dominate modern aquatic ecosystems and are represented by over 32000 extant species. The vast majority of living actinopterygians are teleosts; their success is often attributed to a genome duplication event or morphological novelties. The remainder are ‘living fossils’ belonging to a few depauperate lineages with long-retained ecomorphologies: Polypteriformes (bichirs), Holostei (bowfin and gar) and Chondrostei (paddlefish and sturgeon). Despite over a century of systematic work, the circumstances surrounding the origins of these clades, as well as their basic interrelationships and diagnoses, have been largely mired in uncertainty. Here, I review the systematics and characteristics of these major ray-finned fish clades, and the early fossil record of Actinopterygii, in order to gauge the sources of doubt. Recent relaxed molecular clock studies have pushed the origins of actinopterygian crown clades to the mid-late Palaeozoic [Silurian-Carboniferous; 420 to 298 million years ago (Ma)], despite a diagnostic body fossil record extending only to the later Mesozoic (251 to 66 Ma). This disjunct, recently termed the ‘Teleost Gap’ (although it affects all crown lineages), is based partly on calibrations from potential Palaeozoic stem-taxa and thus has been attributed to poor fossil sampling. Actinopterygian fossils of appropriate ages are usually abundant and well preserved, yet long-term neglect of this record in both taxonomic and systematic studies has exacerbated the gaps and obscured potential synapomorphies. At the moment, it is possible that later Palaeozoic-age teleost, holostean, chondrostean and/or polypteriform crown taxa sit unrecognized in museum drawers. However, it is equally likely that the ‘Teleost Gap’ is an artifact of incorrect attributions to extant lineages, overwriting both a post-Palaeozoic crown actinopterygian radiation and the ecomorphological diversity of stem-taxa.

Juan Marcos Mirande – 2nd expert on this subject based on the ideXlab platform

  • Combined phylogeny of ray-finned fishes (Actinopterygii) and the use of morphological characters in large-scale analyses
    Cladistics, 2017
    Co-Authors: Juan Marcos Mirande

    Abstract:

    This study evaluates the phylogeny of ray-finned fishes (Actinopterygii) combining most available information (44 markers from nuclear and mitochondrial DNA and 274 morphological characters). The molecular partition of the dataset was produced through a pipeline (GB-to-TNT) that allows the fast building of large matrices from GenBank format. The analysed dataset has 8104 species, including representatives of all orders and 95% of the 475 families of Actinopterygii, making it the most diverse phylogenetic dataset analysed to date for this clade of fishes. Analysed morphological characters are features historically consid- ered diagnostic for families or orders, which can be unequivocally coded from the literature. Analyses are by parsimony under several weighting schemes. General results agree with previous classifications, especially for groups with better gene sampling and those long thought (from morphological evidence) to be monophyletic. Many clades have low support and some orders are not recovered as monophyletic. Additional data and synthetic studies of homology are needed to obtain synapomorphies and diagnoses for most clades.

  • Combined phylogeny of ray‐finned fishes (Actinopterygii) and the use of morphological characters in large‐scale analyses
    Cladistics, 2016
    Co-Authors: Juan Marcos Mirande

    Abstract:

    This study evaluates the phylogeny of ray-finned fishes (Actinopterygii) combining most available information (44 markers from nuclear and mitochondrial DNA and 274 morphological characters). The molecular partition of the dataset was produced through a pipeline (GB-to-TNT) that allows the fast building of large matrices from GenBank format. The analysed dataset has 8104 species, including representatives of all orders and 95% of the 475 families of Actinopterygii, making it the most diverse phylogenetic dataset analysed to date for this clade of fishes. Analysed morphological characters are features historically considered diagnostic for families or orders, which can be unequivocally coded from the literature. Analyses are by parsimony under several weighting schemes. General results agree with previous classifications, especially for groups with better gene sampling and those long thought (from morphological evidence) to be monophyletic. Many clades have low support and some orders are not recovered as monophyletic. Additional data and synthetic studies of homology are needed to obtain synapomorphies and diagnoses for most clades.

Adam D Marsh – 3rd expert on this subject based on the ideXlab platform

  • first record of saurichthys Actinopterygii from the upper triassic chinle formation norian of western north america
    Journal of Vertebrate Paleontology, 2017
    Co-Authors: Ben T Kligman, William G Parker, Adam D Marsh

    Abstract:

    Citation for this article: Kligman, B. T., W. G. Parker, and A. D. Marsh. 2017. First record of Saurichthys (Actinopterygii) from the Upper Triassic (Chinle Formation, Norian) of western North America. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1367304.