Molecular Systematics of Lizardfishes (Aulopiformes: Synodontidae)
| Autor: | Shih-Yu Wang, 王世伃 |
|---|---|
| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Lizardfishes are a group of benthic carnivorous fishes that have cylindrical bodies and relatively large mouths, live mostly in the sandy bottom of tropic and sub-tropic seas. Belong to the family Synodontidae, the lizardfishes include 83 currently recognized species in 4 genera, Synodus, Harpadon, Saurida, and Trachinocephalus. However, the taxonomy of the family has been controversial since it had been established by Gill (1861). A robust phylogeny of this family is required for further taxonomy revision. In this study, we aimed to: (1) reconstruct a comprehensive phylogeny of the family Synodontidae along with its aulopiform allies; (2) test the monophyly of the family and the four recognized genera; (3) estimate the divergence times of synodontids under a robust phylogeny; (4) investigate the validity of the existing species within the family with an integrated approach in taxonomy (i.e. species delimitation). To infer the phylogeny of the family, a multi-gene dataset was composed of four nuclear genes (RH, RAG1, ZIC1 and ENC1) and three mitochondrial (COI, 12S, 16S) genes. The datasets used for the species delimitation analysis with two programs (ABGD and bPTP) included 975 mitochondrial COI gene sequences, of which 202 were newly generated in this study and 773 were retrieved from public and private sources. In the results, the Synodontidae was not monophyletic while each of the two subfamilies of the Synodontidae was resolved as a monophyletic group. Therefore, the elevation of the two subfamilies Synodontinae Gill 1861 and Harpadontinae Bleeker 1875 is suggested, i.e., from subfamily level to family level. Within the family, only two out of the four currently recognized genera are monophyletic, which are Harpadon and Trachinocephalus. The monophyletic Harpadon is sister to the clade composed of two of the four well-resolved Saurida lineages, while the monophyletic genus Trachinocephalus is sister to the clade composed of two of the three well-resolved Synodus lineages. The divergence time estimations recovered that the most recent common ancestor of the family Synodontidae arose during the Late Cretaceous, while that of the family Harpadontidae occurred during the Eocene. From the species delimitation analyses, 87 putative species (OTUs) were observed out of the 52 recognized species included in the study, indicating an underestimated biodiversity of the family. This study offers an insight into the systematics of the family Synodontidae, and provides a framework for further taxonomic and evolutionary studies. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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