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Vol. 48 No. 6, 2009
Speciation and Population Structure of Three Trichiurus Species Based on
Mitochondrial DNA
Kui-Ching
Hsu1, Nien-Tsu Shih2, I-Hsun Ni2, and
Kwang-Tsao Shao1,*
1Biodiversity
Research Center, Academia Sinica, Nankang, Taipei 115, Taiwan
2Department of Environmental Biology and Fisheries
Science, National Taiwan Ocean University, Keelung 202, Taiwan
Kui-Ching
Hsu, Nien-Tsu Shih, I-Hsun Ni, and Kwang-Tsao Shao (2009) 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
Neighborjoining 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
tip of South Africa, (3) archipelagoes of the West Pacific, (4) the
southeastern coast of Taiwan, (5) cyclical glacial periods, (6) the
Isthmus of Panama, (7) the 2500 km long stretch of deep water
separating the eastern and western Atlantic, and (8) freshwater plumes
of the Amazon River. Based on current data, the East Indies
Triangle of Indo-West Pacific was either a refuge or a colonization
source for T. sp. 2.
Key words: Trichiurus
lepturus, Trichiurus japonicus,
Trichiurus sp. 2,
Speciation, Phylogeography.
*Correspondence: Fax: 886-2-27883463.
E-mail:zoskt@gate.sinica.edu.tw
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