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Neurosensory anatomy and function in Seymouria
Kayla D Bazzana-Adams1,2, David C Evans1,2, Joseph J Bevitt3
1Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.
Journal of Morphology
|March 15, 2023
Summary
Seymouria, an early amniote, shows primitive brain and inner ear structures, lacking specializations seen in later species. This study reveals key details about its palaeoneuroanatomy and carotid artery morphology.
Area of Science:
- Paleontology
- Evolutionary Biology
- Neuroanatomy
Background:
- Seymouria is a key stem amniote for understanding amniote evolution.
- Previous research focused on osteology; recent studies use computed tomography (CT) for internal features.
Purpose of the Study:
- To reconstruct the first virtual cranial and otic endocasts of Seymouria using neutron CT.
- To reveal previously unrecognized details of Seymouria's palaeoneuroanatomy.
Main Methods:
- Neutron computed tomography (CT) was employed.
- Virtual cranial and otic endocasts were reconstructed.
Main Results:
- The brain and inner ear of Seymouria are largely plesiomorphic compared to crown amniotes.
- No evidence of increased encephalization or braincase ossification was found.
- Carotid artery morphology in Seymouria is similar to basal synapsid and sauropsid lineages, clarifying the plesiomorphic amniote condition.
Conclusions:
- Seymouria's neuroanatomy lacks specializations, despite a probable impedance matching hearing system.
- The findings provide insights into early amniote brain evolution and morphology.
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