3.4. Timing of divergence
The BEAST analyses estimated the origination of the crown
group of the Onthophagini plus Oniticellini to 45.31 Mya (95%
HPD: 35.9–55.5 Mya), i.e. during the Eocene (Fig. 2). The monophyletic
Oniticellini originated around 30.69 Mya (95% HPD:
23.3–38.0 Mya), i.e. during the Oligocene. The New World Onthophagini
started diversifying during the Miocene around
20.42 Mya (95% HPD: 15.5–25.7). The split between the American
and Australian clade occurred three My earlier at ±23.17 Mya (95%
HPD: 17.6–28.7 Mya), while the divergence between the second
Australian clade and the Oriental Gibbonthophagus (‘O1’) was even
younger at ±19.87 Mya (HPD: 15.0–25.3 Mya).