| Summary: | 碩士 === 國立海洋大學 === 漁業科學系碩士在職專班 === 91 === Abstract
The family Scombridae is composed of 15 genera and 50 species of mostly epipelagic marine fishes in the world, including mackerels, Spanish mackerels , bonitos , and tunas. While, there are 11 genera and 22 species of scombrids in Taiwan. They are economically important fishes around the world .
Conventionally, the systematic taxonomy of Scombridae is based on morphology and osteology. In this study, the complete cytochrome b gene sequences (1140 bp) were used to infer the phylogenetic relationships of Scombridae in the coastal waters of Taiwan. All of the 22 and 4 outgroup sequences were subjected to Neighbor-joining, and Maximum parsimony methods. The results of analysis suggest that：(1) Sarda and Thunnus share a common ancestor , so Sarda belongs to Thunnini.(2) Thunnus is a monophyletic group. Axis+Euthynnus +Katsuwonus is monophyletic , too. The genetic distances between Euthynnus and Katsuwonus is very short , so it seems to be reasonable for combining these genera to one genus. (3) Grammatorcynus is close to outgroup , so it is a primitive species of scombrid. It should be categorized to Scombrini . (4) Acanthocybium and Gymnosarda share a common ancestor, and they are the sister groups of Sardini. Acanthocybium belongs to Sardini. (5) The classification of Sardini category is unstable , and the members of Sardini need to be re-evaluated for their position in Scombridae.
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