Dolichocebus gaimanensis Is Not a Stem Platyrrhine

Area of Science:

• Paleontology
• Primatology
• Evolutionary Biology

Background:

• The evolutionary history of New World monkeys (platyrrhines) remains incompletely understood.
• Previous hypotheses suggested early platyrrhines might be monophyletic and outside the crown radiation.

Purpose of the Study:

• To investigate the phylogenetic relationships between early Miocene platyrrhines from Patagonia and Colombia.
• To test existing hypotheses on platyrrhine evolutionary patterns.

Main Methods:

• Comparative morphological analysis of lower molars and canine morphology.
• Phylogenetic and phenetic analyses of fossil platyrrhine specimens.

Main Results:

• Lower molars of Dolichocebus gaimanensis and Laventiana annectens are indistinguishable.
• Canine morphology suggests Dolichocebus is closely related to Saimiri (cebines).
• These species link southern and northern South American Miocene monkey faunas, refuting early platyrrhine monophyly.

Conclusions:

• Dolichocebus and Laventiana are classified as congeners, representing a link between distinct Miocene platyrrhine faunas.
• Findings support the Long-Lineage Hypothesis, emphasizing prolonged ecophylogenetic stability in low-level taxonomic clades.
• The study refutes the hypothesis of monophyletic early platyrrhines outside the crown radiation.