Using two calibration points, the ages of the clade including C.
sanguinolentus, C. lividus and C. conco (C. diadema was not included
in this analysis, because no 28S sequence was available for it) and
the clade including C. lividus and C. conco were estimated at
7.84 mya (5.12–12.46) and 2.738 mya (1.11–4.73) respectively
(Fig. 3).