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Direct quantification of skeletal pneumaticity illuminates ecological drivers of a key avian trait.

Authors :
Burton MGP
Benson RBJ
Field DJ
Source :
Proceedings. Biological sciences [Proc Biol Sci] 2023 Mar 29; Vol. 290 (1995), pp. 20230160. Date of Electronic Publication: 2023 Mar 15.
Publication Year :
2023

Abstract

Skeletal pneumaticity is a key feature of extant avian structure and biology, which first evolved among the non-flying archosaurian ancestors of birds. The widespread presence of air-filled bones across the postcranial skeleton is unique to birds among living vertebrates, but the true extent of skeletal pneumaticity has never been quantitatively investigated-hindering fundamental insights into the evolution of this key avian feature. Here, we use microCT scans of fresh, frozen birds to directly quantify the fraction of humerus volume occupied by air across a phylogenetically diverse taxon sample to test longstanding hypotheses regarding the evolution and function of avian skeletal pneumatization. Among other insights, we document weak positive allometry of internal air volume with humeral size among pneumatized humeri and provide strong support that humeral size, body mass, aquatic diving, and the presence or absence of pneumaticity all have independent effects on cortical bone thickness. Our quantitative evaluation of humeral pneumaticity across extant avian phylogeny sheds new light on the evolution and ontogenetic progression of an important aspect of avian skeletal architecture, and suggests that the last common ancestor of crown birds possessed a highly pneumatized humerus.

Details

Language :
English
ISSN :
1471-2954
Volume :
290
Issue :
1995
Database :
MEDLINE
Journal :
Proceedings. Biological sciences
Publication Type :
Academic Journal
Accession number :
36919426
Full Text :
https://doi.org/10.1098/rspb.2023.0160