Phylogenetic Analysis
Based on previous studies (Li et al. 2009, Hofmann et al. 2017), we
identified Scutiger boulengeri containing six clades, for the
first time, after max range field works. To construct a phylogeny forS. boulengeri clades, we used MEGA-X (Kumar et al. 2018) to align
six selected mtDNA genomes (Genbank MW600725–MW600729 and FJ463132)
with genome from outgroup Oreolalax omeimontis (Genbank
EU180928). Phylogenetic trees were constructed separately by using
maximum likelihood (ML) and Bayesian inference (BI) methods, both of
which were implemented in PhyloSuite v1.2.1 (Zhang et al. 2020). The
best-fit BIC substitution model (TPM2 + F + G4) was selected in
ModelFinder (Kalyaanamoorthy et al. 2017). Divergence time for the
reconstructed trees was estimated with the
Reltime ML method using MEGA-X
(Kumar et al. 2018). Based on previous research, we choose the Most
Recent Common Ancestor (MRCA) of Scutiger and Oreolalax(53 Ma) as calibration point (Hofmann et al. 2017).