Table 9. Test results for group separation of compared species within clade 6 along first two PCA axes (PC1 and PC2).

PC	Group pairwise	Estimate	SE	df	t. ratio	P-value	Sig
PCA scores for each axis were grouped by species and compared pairwise using Tukey HSD tests to adjust for multiple comparisons. Sig: Significance levels. NS: Not significant. **: P<0.01; ***: P<0.001.
1	Yanshan – huishuiensis	–4.90	0.208	21	–23.581	<0.001	***
	Yanshan – nahangensis	–6.46	0.296	21	–21.811	<0.001	***
	huishuiensis – nahangensis	–1.56	0.313	21	–4.984	<0.001	***
2	Yanshan – huishuiensis	1.13	0.612	21	1.840	0.1812	NS
	Yanshan – nahangensis	–2.01	0.872	21	–2.300	0.0778	NS
	huishuiensis – nahangensis	–3.13	0.922	21	–3.398	0.0073	**