Morphological differences between FCDK and FCSH
We checked more than 50 individuals of each strain and found two morphological characteristics that could distinguish between adults of FCDK and FCSH (Figure 1a-h): the numbers of seta on the retinaculum (2 or 3 for FCSH vs. only 1 for FCDK), which was not included by Tully & Potapov (2015), and the numbers of ventral setae on the third segment of the thorax (3(4-6)+3(4-6) for FCSH vs. 2(3)+2(3) for FCDK), which is consistent with the observation of character 11 in Tully & Potapov (2015). However, the numbers of setae on dens and manubrium vary greatly between individuals, and we have not confirmed the differences corresponding characters 12 and 17 in Tully & Potapov (2015).