Nsfdeb-BSF: evolution of the aerodynamic feathered wing: development of shape-function relationship through deep time

The National Science Foundation Division of Environmental Biology awarded the Field Museum of Natural History $811,851 on September 1, 2026, for research on the evolution of the aerodynamic feathered wing under the Biological Sciences program (CFDA 47.074).

The project combines fossil evidence from feathered dinosaurs spanning 165 million years with data from living birds to examine how forelimb feathers in pennaraptoran dinosaurs evolved into the complex aerodynamic wing system present in modern birds. The research addresses three specific aspects: primary feather count and variation, wing position as a proxy for wing-folding mechanisms, and the interaction between wing function and molt in slower-growing non-avian dinosaurs and early birds. Findings will be developed into an interactive exhibit at the Field Museum and disseminated through the museum's Teen Volunteer Program.

The award runs from September 1, 2026, through August 31, 2029, with work performed in Chicago, Illinois.

Abstract

Birds are the most successful group of land vertebrates on our planet and the only dinosaurs to survive the end-cretaceous mass extinction. Although feathers are one of the most defining avian traits, these unique structures were inherited from non-avian dinosaurs. The evolution of flight in dinosaurs is one of the most important evolutionary transitions in earth?s history, underpinning the enormous diveristy of birds today. Although skeletal changes are well documented, how feathers evolved into the aerodynamic wing is very poorly understood. This project combines information from living birds and feathered dinosaur fossils spanning 165 million years to explore how the feathers on the forelimbs of pennaraptoran evolved into the complex and efficient aerodynamic system present in birds today. This project explores the wing in three aspects: primary feather count and variation; wing position as a proxy for the wing folding mechanism; and the interaction between wing function and molt in slower growing non-avian dinosaurs and early birds. The findings of this work will be developed into an interactive exhibit at the field museum of natural history and findings will be disseminated via the teen volunteer program at the field museum. The origin and evolution of the feathered wing stands among the most consequential innovations in vertebrate history, enabling powered flight and shaping the ecological success of feathered dinosaurs including modern birds. Skeletal transformations underlying the transition from terrestrial non-avian dinosaur to volant avian dinosaur are well documented, while the structure and dynamics of the feathered wing from a non-aerodynamic to aerodynamic structure remain far less understood. This research addresses this knowledge GAP by examining how wing morphology and function CO-evolved through deep time with the appearance of volant locomotion in pennaraptoran theropod dinosaurs, integrating paleontological and neontological data to uncover how selective pressures shaped wing morphology across 165 million years of evolution, from the oldest known pennaraptoran dinosaurs with wing-like arrangements of feathers to modern birds. Wing morphology includes both fixed and variable components. Fixed traits, such as the skeleton, interact with variable traits, most notably feathers, which are subject to wear and molt. Fixed traits in neornithines, like patagia, evolved over time in extinct pennaraptora affecting forelimb function. Among volant neornithines, the number of primary flight feathers is a fixed trait varying by only a difference of two feathers between all studied taxa, but preliminary data suggests IT is variable in non-volant taxa. This suggests the number of primary feathers is controlled by aerodynamic constraints, yet how and when this pattern evolved is unknown. We pursue three interconnected aims: (i) testing whether post-mortem wing position reflects musculoskeletal adaptations for flight, offering a novel proxy for assessing flight ability in fossils; (II) evaluating the ratio between wing feather length and body size among feathered dinosaurs, to assess the frequency of flight-feather molt across growth stages and determine if protracted growth strategies impacted flight ability across the molt cycle; and (III) analyzing variation in primary feather number to identify developmental and aerodynamic constraints underlying the evolution of the feathered wing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.