Timing and tempo of primate speciation

Area of Science:

• Evolutionary Biology
• Molecular Phylogenetics
• Primate Taxonomy

Background:

• Molecular clocks provide estimates for divergence times across primate evolutionary history.
• Previous studies established divergence times for various primate taxonomic levels, including phylogroups, species, and genera.

Purpose of the Study:

• To estimate the typical maximum duration of speciation in primates using molecular clock data.
• To re-evaluate the classification of humans and chimpanzees based on molecular divergence estimates.

Main Methods:

• Utilizing published molecular clocks to calculate divergence times for primate phylogroups, species, and genera.
• Analyzing differences in divergence times among major primate groups (infraorders and superfamilies).
• Estimating speciation duration by considering prezygotic and post-zygotic isolation mechanisms.

Main Results:

• Primate speciation is estimated to be relatively rapid (1.1 Ma) compared to many vertebrates.
• Speciation duration ranges from 1.0 to over 4.0 million years, depending on the isolation mechanisms considered.
• Typical primate genus age is approximately 5.3 Ma, with variations across major groups.

Conclusions:

• Molecular divergence data suggest primate speciation is a protracted process, potentially taking millions of years.
• The classification of humans and chimpanzees warrants reconsideration using a molecular yardstick approach.
• Molecular analyses offer three potential taxonomic frameworks with significant implications for understanding hominid evolution.