3Genetic structure
We reconstructed the phylogenetic relationships between the Naumann’s
and dusky thrush complexes and the red-throated and black-throated
thrush complexes based on haplotype sequences of the partial ND2 and COI
genes (Fig. 1). The BI and ML trees of the dataset had similar
topologies, and only the nodes of two thrush complexes were
significantly supported by the posterior probability (PP>
95%) and the bootstrap value (BS> 75). The rest of the
nodes within the Naumann’s and dusky thrush complexes or the
red-throated and black-throated thrush complexes were weakly supported
in both trees. Moreover, the haplotypes of the Naumann’s and dusky
thrushes and the red-throated and black-throated thrushes were mixed,
and no monophyletic subclade was observed for any thrush. We found that
when combined with the identification of morphological characteristics,
the haplotypes of most individuals were correctly assigned to their
corresponding species or Turdus complex. There were a few
haplotypes from intermediate specimens mixed between the twoTurdus complexes. Three haplotypes from Naumann’s thrush and one
haplotype from the dusky thrush were distributed in the clade of
red-throated and black-throated thrush complexes. In contrast,
three haplotypes from the black-throated thrush and four haplotypes from
the red-throated thrush were located in the clade of Naumann’s and dusky
thrush complexes.
Based on the microsatellite dataset, a NJ tree was constructed based on
SADs between individuals from the Naumann’s and dusky thrush complexes
and the red-throated and black-throated thrush complexes (Fig. 2).
Although the test performance was worse when SADs were used (data not
shown), and the bootstrap support values were relatively low, all
individuals were divided into two groups, corresponding to two thrush
complexes. Notably, each group was mixed with several individuals from
other groups.