Primate phylogenetic relationships and divergence dates inferred from complete mitochondrial genomes

Area of Science:

• Evolutionary Biology
• Molecular Phylogenetics
• Paleontology

Background:

• Primate origins and divergence times are debated due to limited early fossil evidence.
• Molecular estimates often conflict with fossil data, suggesting origins in the Cretaceous, predating known fossils.

Purpose of the Study:

• To resolve primate evolutionary history and divergence times using a comprehensive mitogenomic dataset.
• To investigate the impact of fossil calibrations on primate age estimates.
• To test the short-fuse model of primate origins.

Main Methods:

• Assembled 87 mammalian mitochondrial genomes, including 62 primate species from all families.
• Newly sequenced 11 mitochondrial genomes (8 Old World monkeys, 3 strepsirrhines).
• Performed phylogenetic analyses and explored 17 fossil calibrations to date the mitogenomic tree.

Main Results:

• Confirmed monophyly for all major primate clades with robust phylogenetic support.
• Resolved the positions of tarsiers and colugos relative to strepsirrhines and anthropoids.
• Estimated the Strepsirrhine/Haplorhine split at ~74Ma, placing crown primate origins in the Late Cretaceous.

Conclusions:

• Supports a Late Cretaceous origin for crown primates, consistent with a short-fuse model of rapid early diversification.
• Suggests that the early primate fossil record is likely undersampled.
• Provides a well-resolved phylogenetic framework for understanding primate evolution.