Abstract
Modern birds possess highly encephalized brains that evolved from non-avian dinosaurs. Evolutionary shifts in developmental timing, namely juvenilization of adult phenotypes, have been proposed as a driver of head evolution along the dinosaur-bird transition, including brain morphology. Testing this hypothesis requires a sufficient developmental sampling of brain morphology in non-avian dinosaurs. In this study, we harness brain endocasts of a postnatal growth series of the ornithischian dinosaur Psittacosaurus and several other immature and mature non-avian dinosaurs to investigate how evolutionary changes to brain development are implicated in the origin of the avian brain. Using three-dimensional characterization of neuroanatomical shape across archosaurian reptiles, we demonstrate that (i) the brain of non-avian dinosaurs underwent a distinct developmental trajectory compared to alligators and crown birds; (ii) ornithischian and non-avialan theropod dinosaurs shared a similar developmental trajectory, suggesting that their derived trajectory evolved in their common ancestor; and (iii) the evolutionary shift in developmental trajectories is partly consistent with paedomorphosis underlying overall brain shape evolution along the dinosaur-bird transition; however, the heterochronic signal is not uniform across time and neuroanatomical region suggesting a highly mosaic acquisition of the avian brain form.
Original language | English |
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Article number | 7415 |
Number of pages | 10 |
Journal | Nature Communications |
Volume | 15 |
Issue number | 1 |
DOIs | |
Publication status | Published - 28 Aug 2024 |
Bibliographical note
Publisher Copyright:© The Author(s) 2024.
Keywords
- Animals
- Dinosaurs/anatomy & histology
- Brain/anatomy & histology
- Biological Evolution
- Birds/anatomy & histology
- Fossils
- Skull/anatomy & histology
- Phylogeny
- Alligators and Crocodiles/anatomy & histology