Speciation and Population Structure of Three Trichiurus Species Based on Mitochondrial DNA

Abstract

of three Trichiurus species based on mitochondrial DNA. Zoological Studies 48(6): 835-849. This study integrated most available genetic data of the “Trichiurus lepturus complex ” and examined its species status and population structure using mitochondrial (mt) DNA sequences. Both the maximum-parsimony and Neighbor-joining distance trees supported 3 clear branches at 100 % bootstrap value support. Due to a decisive genetic difference based on mtDNA cytochrome b, cytochrome oxidase subunit I, and 16S ribosomal RNA with the Kimura 2 parameter or maximum composite likelihood models, all historically confusing “T. lepturus complex” morphs were suggested to be 3 separate species: T. japonicus, T. lepturus, and T. sp. 2. This study suggested that T. lepturus from the Indo-Pacific in previous studies and T. sp. 2 are the same species. During the Miocene, these 3 Trichiurus species diverged from each other. According to the mtDNA phylogeographical patterns presented here, the vicariance events important to the speciation or structure of the “T. lepturus complex ” were: (1) a warming event occurring around Japan during the middle Miocene, (2) cold water upwelling close to the