2.5 | Divergence time estimation
We inferred divergence times for the Sinocyclocheilus using the MSC model in SNAPP. The absence of a specific fossil record provides a calibration for Sinocyclocheilus . To investigate the divergence times of geographic populations of Sinocyclocheilus in the central Yunnan Basin in accordance with molecular clock theory, we set three calibration points from previous studies on this group (Chen et al., 2009; Mao et al., 2021; Yang et al., 2021) and set the differentiation rate of S. grahami at 3.51 × 10-9 years (Yang et al., 2016). We ran an independent SNAPP analysis with 20 million MCMC generations, sampling at every 2,000 steps. Stationarity of the BEAST 1.8.2 (Drummond et al., 2012). analysis was assessed using TRACER 1.7.1 (Rambaut et al., 2018) and was considered as evidence of convergence when ESS values greater than 200. Maximum clade credibility (MCC) trees were obtained using TREEANNOTATOR 2.4.3 to burn-in the initial 10% of the all samples.