Miocene cercopithecoidea from the Tugen Hills, Kenya.

Area of Science:

• Paleontology
• Primate Evolution
• African Paleoecology

Background:

• The Tugen Hills, Kenya, contain Miocene-Pleistocene fossil sediments (15.5-0.25 Ma), offering insights into poorly understood African faunal evolution and environmental changes.
• This region is crucial for understanding primate evolution, with previous discoveries significantly contributing to the field.

Purpose of the Study:

• To describe new cercopithecoid primate fossils from Miocene deposits in the Tugen Hills.
• To evaluate previously described material and expand understanding of primate diversity and evolution in Africa.

Main Methods:

• Excavation and analysis of fossiliferous sediments from dated sites (Muruyur, Mpesida, Lukeino, Ngorora Formations).
• Taxonomic identification of cercopithecoid specimens, including Victoriapithecidae and colobines.
• Comparative analysis of fossil morphology with extant primate taxa and molecular divergence estimates.

Main Results:

• Identification of Victoriapithecidae gen. et sp. indet., cf. Parapapio lothagamensis, and at least two distinct colobine taxa.
• Fossil evidence suggests an extended geographic range for cf. Parapapio lothagamensis.
• Discovery of early African colobines (Tribe: Colobina) with derived characters aligning with molecular divergence data.

Conclusions:

• The Tugen Hills fossils represent some of the earliest known members of the modern African colobine radiation.
• Early African colobines were likely primarily arboreal, with semi-terrestrial forms representing secondary adaptations.
• These findings challenge previous hypotheses on colobine locomotor evolution and diversification timelines.