Phylogeny of Rajiformes Inferred from Mitochondrial 12S Ribosomal DNA Sequences
| Autor: | Chin-Shen Chen, 陳進生 |
|---|---|
| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 Taxonmically, Rajiformes is included in subclass Elasmobranchii under class Chondrichthyes, being divided into 4 suborders and 12 families. The phylogenetic relationships within rajiformes are still in vague. In order to infer their phylogenetic relationships, a molecular approach with mtDNA 12S rRNA sequencing of 12 families and 33 species of rajiformes, chimaeras, and sharks, were analyzed. The results suggest that Rajiformes is not a monophyletic group. Subclass Elasmobranchii can be subdivided into two monophyletic groups: one with Torpedinoidei （Torpedinidae and Narcinidae）, Pristoidei （Pristidae）, Rajoidei （Rhinidae, Rhinobatidae and Rajidae） and sharks; another, Myliobatoidei which includes families Plesiobatidae, Hexatrygonidae, Dasyatidae, Urolophidae, Gymnuridae and Myliobatidae. Torpedinoidei is considered as the plesiomorphic sister group of sharks, Pristoidei and Rajoidei. Myliobaoidei is probably the most advanced group within the class Chondrichthyes. The significant finding we discover in this study is the clarification of toxonomial position of sharks, which should be clustered with skates phylogenetically. We hoped that the results present may deduce a new thinking of the phylogeny of Chondrichthyes. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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