When we repeated this analysis removing the fossil calibration
date based on Stirtonia, estimated divergences among the atelids
are shifted to be slightly more recent. With no Stirtonia calibration,
the estimated age of the most recent common ancestor (MRCA) of
the family Atelidae is inferred to be 11.1 Ma and that of Ateles to
be 5.7 Ma (Table 6). Exclusion of the A. marginatus sequence from
our dating analysis likewise yields slightly more recent divergence
date estimates among the atelids. Here, the MRCA of atelids is estimated
at 13.0 Ma and that of Ateles is inferred to be even more
recent, at 4.4 Ma (Table 6).