DNA Barcoding, Identification and Validation of the puffer fish (Order: Tetraodontiformes) in China Coastal Waters

Tetraodontiformes is a special group of higher teleosts, with a long and problematic taxonomic history due to their wide distribution and species diversity. It is a difficult task for both professionals and nonprofessionals to accurately identify all species only according to morphological characteristics. DNA barcoding can identify species at the molecular level. In this study, we collected 616 specimens of Tetraodontiformes and their DNA barcodes from the coastal waters of China. According to the morphological characteristics, 50 species were preliminarily identified, belonging to 23 genera, 6. Among them, DNA barcoding analysis showed that Takifugu pseudommus and Takifugu chinensis are the synonyms of Takifugu rubripes. And Lagocephalus wheeleri is the synonym of Lagocephalus Spadiceus. The third important finding is that the species of Takifugu have close genetic relationship. If T. rubripes, T. pseudommus and T. chinensis are taken as one species, the average interspecific genetic distance of Takifugu is 6.21 times of the average intraspecific genetic distance, which does not reach the DNA barcode threshold of more than 10 times proposed by Hebert. Among them, the genetic distance between T. oblongus and T. stictonotus is the largest, 0.045; And between T. bimaculatus and T. flavidus is the smallest, only 0.013. However, species can be clustered into separate clades in the NJ tree. In conclusion, this study provided molecular basis for solving the problem of confusion in the classification of Tetraodontiformes, it found that there are synonym phenomena in the order, and provided molecular evidence for clarifying the valid species names of Lagocephalus Spadiceus and Takifugu rubripes. The results can provide reliable DNA barcoding information for the identification and classification of Tetraodontiformes, and also provide technical support for the development and utilization of puffer fish resources and the identification of the original components of related commodities on the aquatic product market.