Endocranial development in non-avian dinosaurs reveals an ontogenetic brain trajectory distinct from extant archosaurs

Logan King*, Qi Zhao, David L Dufeau, Soichiro Kawabe, Lawrence Witmer, Chang-Fu Zhou, Emily J Rayfield, Michael J Benton, Akinobu Watanabe

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

1 Citation (Scopus)

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 languageEnglish
Article number7415
Number of pages10
JournalNature Communications
Volume15
Issue number1
DOIs
Publication statusPublished - 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

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