Skip to Content

Beyond endocasts: using predicted brain structure volumes of extinct birds to assess neuroanatomical and behavioral inferences Project ID: 00000C882 Public
35 Media · 33 Specimens · Managed by: Catherine Early

The shape of the brain influences skull morphology in birds, and both traits are driven by phylogenetic and functional constraints. Studies on avian cranial and neuroanatomical evolution are strengthened by data on extinct birds, but complete, 3D-preserved vertebrate brains are not known from the fossil record, so brain endocasts often serve as proxies. Recent work on extant birds shows that the Wulst and optic lobe faithfully represent the size of their underlying brain structures, both of which are involved in avian visual pathways. The endocasts of seven extinct birds were generated from microCT scans of their skulls to add to an existing sample of endocasts of extant birds, and the surface areas of their Wulsts and optic lobes were measured. A phylogenetic prediction method based on Bayesian inference was used to calculate the volumes of the brain structures of these extinct birds based on the surface areas of their overlying endocast structures. This analysis resulted in hyperpallium volumes of five of these extinct birds and optic tectum volumes of all seven extinct birds. Phylogenetic ANCOVA (phyANCOVA) were performed on regressions of the brain-structure volumes and endocast structure surface areas on various brain size metrics to determine if the relative sizes of these structures in any extinct birds were significantly different from those of the extant birds in the sample. Phylogenetic ANCOVA indicated that no extinct birds studied had relative hyperpallial volumes that were significantly different from the extant sample, nor were any of their optic tecta relatively hypertrophied. The optic tectum of Dinornis robustus was significantly smaller relative to brain size than any of the extant birds in our sample. This study provides an analytical framework for testing the hypotheses of potential functional behavioral capabilities of other extinct birds based on their endocasts.

Filter works:
Media Type
Object
Organization
Publication Status
Taxonomy (Name)
Team
Project
Data Manager
Data Uploader
View results as:
List Gallery
List of media items in this team
  ID Part Object Taxonomy Type Date Added Publication Status  
000116295 brain endocast FMNH:Birds:390488 Larus philadelphia Mesh 2020-05-20 Restricted Download  
000116294 brain endocast USNM:BIRDS:USNM 612711 Dacelo novaeguineae Mesh 2020-05-20 Restricted Download  
000116290 brain endocast amnh:birds:SKEL-8560 Crypturellus tataupa Mesh 2020-05-20 Restricted Download  
000116288 brain endocast amnh:birds:SKEL-2310 Colinus virginianus Mesh 2020-05-20 Restricted Download  
000116286 brain endocast amnh:birds:SKEL-21616 Bonasa umbellus Mesh 2020-05-20 Restricted Download  
000116287 brain endocast amnh:birds:SKEL-18788 Buteo swainsoni Mesh 2020-05-20 Restricted Download  
000116281 brain endocast USNM:BIRDS:USNM 343978 Ardea cinerea cinerea Mesh 2020-05-20 Restricted Download  
000116279 brain endocast CM:Birds:S15896 Apus apus Mesh 2020-05-20 Restricted Download  
000116277 brain endocast USNM:BIRDS:USNM 18278 Apteryx australis mantelli Mesh 2020-05-20 Restricted Download  
000116275 brain endocast USNM:BIRDS:USNM 613408 Amazilia tzacatl Mesh 2020-05-20 Restricted Download  
Number of results to display per page
Showing 11 - 20 of 35