3.3 | Species delimitation
At present, Sinocyclocheilus grahami is the onlySinocyclocheilus species described from Dianchi Lake (Regan,
1904). This species is distributed in the upper reaches of the Pudu
River and in a tributary on the right of the Jinsha River. In addition
to the S. grahami , three other Sinocyclocheilus species,S. guanduensis , S. huanglongdongensis and S. heiare known from (Xiao et al., 2004). Based on our examination of type
specimens of these three species, it is believed that the DNA sequence
results show that they are very different from each other, which is due
to the high genetic diversity of S. grahami . As the fourSinocyclocheilus species are not clearly differentiated in
morphology, S. guanduensis , S. huanglongdongensis andS. hei are considered to be synonyms of S. grahami (Zhao
& Zhang, 2009). The maximum likelihood (ML) tree revealed that theSinocyclocheilus populations from the Chenglong vauclusian spring
(C) and the Fuming vauclusian spring (F) in Dianchi Lake are clustered
within Sinocyclocheilus tingi . Furthermore, the morphological
characteristics of individuals from these populations were clearly
distinct from those of S. grahami and the synonymized taxaS. guanduensis , S. huanglongdongensis and S. hei .
We therefore propose that individuals from the Chenglong vauclusian
spring (C) and Fuming vauclusian spring (F) populations constitute an
undescribed Sinocyclocheilus species, which we intend to formally
describe at a later stage.
3.4 | Divergence
times estimates
Based on the RAD-seq data, we estimated the age of the most recent
common ancestor (MRCA) of Sinocyclocheilus in the central Yunnan
Basin at approximately 3.75~3.11 Ma. The earliest
differentiation event occurred at 2.54~2.15 Ma, between
the Mile (YN-ML) and Qujing (YN-QJ) populations. This was followed by
the differentiation of the Dianchi and Fuxian lake population (YN-DF)
and the Qujing population (YN-QJ) 1.43~1.18 Ma(Fig. 3) . The relatively late tectonic uplift of the Tibetan
Plateau 3.6 Ma (Qingzang movement: 3.6~1.7 Ma, Kunhuang
movement: 1.1~0.6 Ma) may have affected the population
dynamics of Sinocyclocheilus in the central Yunnan Basin.