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Evidence for high-frequency hearing in a Permian stem reptile
Kelsey M Jenkins1, Rachel C Fleming2, Juan D Daza3
1Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA. jenkinskel@si.edu.
Nature Communications
|December 19, 2025
Summary
High-frequency hearing in reptiles evolved earlier than previously thought. Biomechanical analyses reveal that the stem reptile Youngina capensis likely possessed a tympanum and could hear high frequencies, suggesting this ability originated in the common ancestor of reptiles.
Area of Science:
- Paleontology
- Evolutionary Biology
- Bioacoustics
Background:
- The evolutionary history of hearing in reptiles remains unclear, with previous hypotheses suggesting independent evolution of tympanic hearing in different lineages.
- Quantitative support for the capacity of early reptiles to hear high frequencies is lacking.
Purpose of the Study:
- To investigate the evolutionary history of hearing in stem reptiles using functional and morphometric analyses.
- To determine the hearing capabilities of the stem reptile Youngina capensis and its implications for early reptilian hearing.
Main Methods:
- Functional and morphometric analyses of the reptilian stapes, including fossil data.
- Harmonic response analyses to assess stapedial displacement.
- Flexible discriminant analysis to predict tympanum presence.
Main Results:
- The stapes of Youngina capensis exhibited proximodistal displacement comparable to tympanic squamates.
- Y. capensis was predicted to possess a tympanum, while early-diverging stem reptiles were classified as low-frequency bone conductors.
- The evolution of an annular ligament, a slender stapes, and a tympanum facilitated hearing.
Conclusions:
- Relatively high-frequency hearing was likely present in the common ancestor of reptiles.
- This capability originated by the late Permian, challenging previous assumptions about early reptilian auditory evolution.
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