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Amphipithecine primates are stem anthropoids: cranial and postcranial evidence.
J-J Jaeger1, C Sein2, D L Gebo3
1Laboratory PALEVOPRIM, UMR CNRS 7262, University of Poitiers, 6 Rue Michel Brunet, 86073 Poitiers Cedex 9, France.
Proceedings. Biological Sciences
|November 10, 2020
Summary
Fossil primate Ganlea megacanina cranial remains reveal it as a stem anthropoid, not an adapiform strepsirrhine. This finding clarifies early anthropoid evolution and Asian origins.
Area of Science:
- Paleontology
- Primate Evolution
- Anthropoid Origins
Background:
- The phylogenetic position of Myanmar amphipithecines, including Ganlea, has been debated since their discovery.
- Previous fossil evidence, primarily jaw fragments, lacked cranial elements crucial for resolving their evolutionary relationships.
Purpose of the Study:
- To investigate the phylogenetic status of amphipithecines using new cranial and skeletal remains.
- To clarify the early evolution of anthropoid cranial and skeletal features.
Main Methods:
- Analysis of cranial and associated ulna remains from a single individual of Ganlea megacanina.
- Comparative anatomical study of dentognathic, ulna, and skull features with extant and fossil primates.
Main Results:
- Ganlea megacanina exhibits anthropoid-like dentognathic traits and specific ulna and skull features (e.g., lacrimal duct orientation, orbital rim, fused metopic suture).
- Unlike crown anthropoids, Ganlea lacks postorbital closure, indicating this feature evolved later and convergently in tarsiers and anthropoids.
- Amphipithecines are reclassified as stem anthropoids.
Conclusions:
- Ganlea megacanina represents a stem anthropoid, providing insights into early anthropoid cranial and skeletal evolution.
- The findings support the hypothesis of anthropoid origins and early diversification in Asia.
- Postorbital closure evolved independently in anthropoids and tarsiers.
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