| Autor: |
Sequeira, S. E. K., Sequiera, S.E.K., Coates, M. I., Coates, M.I. |
| Předmět: |
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| Zdroj: |
Palaeontology; Mar2000, Vol. 43 Issue 1, p153, 20p, 3 Black and White Photographs, 6 Diagrams, 1 Map |
| Abstrakt: |
The partly articulated specimen of the Palaeozoic (Early Carboniferous) chondrichthyan 'Cladodus'neilsoniTraquair from East Kilbride has been known since the late nineteenth century. As such, 'C.'neilsoniTraquair has been cited in numerous publications, but it has become increasingly clear that its anatomy and systematic affinities are obscure. This comprehensive redescription of 'C.'neilsonireveals new details of the neurocranium (including presence of an otico-occipital fissure), dentition, visceral arches (clarifying the condition of the basibranchial pattern plus elongate copula), and pectoral fin. These data refute previously suggested synonymies, such as between 'C'neilsoniand the contemporaneous BearsdenStethacanthus. Attribution of 'C.'neilsonito the taxonomically unsupportable genus 'Cladodus' is rejected, and the species is redesignated asGutturensisneilsonigen. nov. Preliminary cladistic analysis placesGutturensisneilsoniwithin a polytomy includingStethacanthus, the symmoriidCobelodus, and the root of a monophyletic group of neoselachian-like genera. ' Cladodont' as a diagnostic term for early chondrichthyan teeth is found to be insufficiently precise, referring to an ill-defined grade of tooth morphologies present in a wide variety of Palaeozoic genera. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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