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Vol. 46 No. 5, 2007
Phylogeography of the Taiwanese Endemic Hillstream Loaches, Hemimyzon formosanus and H. taitungensis (Cypriniformes: Balitoridae)
Tzi-Yuan Wang1,2, Te-Yu Liao1,3, and Chyng-Shyan Tzeng1,*
1Department of Life Science, National Tsing Hua University, 101 Kuang-Fu Road, Sec. 2, Hsinchu 300, Taiwan
2Genomics
Research Center, Academia Sinica, 128 Academia Road, Sec. 2, Nankang,
Taipei 115, Taiwan. Tel: 886-2-27898756. Fax: 886-2-27898757. E-mail:
d868210@life.nthu.edu.tw
3Department of Vertebrate Zoology, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden
Tzi-Yuan Wang, Te-Yu Liao, and Chyng-Shyan Tzeng (2007)
Variations in nucleotide sequences within the mitochondrial control
region were used to determine the paleogeography of speciation and
diversification of 2 balitorids endemic to Taiwan. Examination of 11
populations of Hemimyzon formosanus and 5 populations of H. taitungensis
respectively revealed 23 and 11 haplotypes within the mitochondrial
control regions. Utilizing the neighbor-joining method and
maximum-parsimony trees, we showed the presence of 3 groups and 2
subgroups in H. formosanus, and 1 group in H. taitungensis. The nested clade analysis, a method with a higher resolution, revealed that the 1 group of H. taitungensis
could be further divided into 2 subgroups on the minimum spanning
network. The nested clade analysis predicted the evolutionary
divergence of populations in H. formosanus due to past fragmentation; furthermore, dispersion among populations of H. taitungensis
was caused by long-distance colonization. The moderate gene flow and
low genetic divergence within the mitochondrial control region suggest
that local range expansion and recent colonization occurred in H. formosanus in west-central Taiwan and in H. taitungensis in eastern Taiwan. Our study showed that one of the major influences on the speciation of both western H. formosanus and eastern H. taitungensis
was the Central Mountain Range of Taiwan. Moreover, deep genetic
divergence and morphological differences suggest new phylogenetic
species exist within H. formosanus.
Key words: Balitoridae, Morphology, D-loop, Evolutionary history, Cryptic species.
*Correspondence: Tel: 886-3-5742765. Fax: 886-3-5742765. E-mail:cstzeng@life.nthu.edu.tw
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