Origin of flight: Could ‘four-winged’ dinosaurs fly?

  title={Origin of flight: Could ‘four-winged’ dinosaurs fly?},
  author={Kevin Padian and Kenneth P Dial},
Arising from: X. Xu et al. 421, 335–340 (2003); F. Zhang & Z. Zhou 431, 925 (2004); X. Xu et al. reply; F. Zhang et al. replyOur understanding of the origin of birds, feathers and flight has been greatly advanced by new discoveries of feathered non-avian dinosaurs, but functional analyses have not kept pace with taxonomic descriptions. Zhang and Zhou describe feathers on the tibiotarsus of a new basal enantiornithine bird from the Early Cretaceous of China. They infer, as did Xu and colleagues… 
A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus
The extensive feathering of this specimen, particularly the attachment of long pennaceous feathers to the pes, sheds new light on the early evolution of feathers and demonstrates the complex distribution of skeletal and integumentary features close to the dinosaur–bird transition.
The Extent of the Preserved Feathers on the Four-Winged Dinosaur Microraptor gui under Ultraviolet Light
Examination of the Microraptor gui specimen under ultraviolet light reveals that these feathers actually reach the body of the animal and were not disassociated from the bones, and that their arrangement and orientation is likely correct.
Hind Wings in Basal Birds and the Evolution of Leg Feathers
Together these fossils show that early avialans possessed four wings, rather than two, and provide solid evidence for the existence of enlarged leg feathers on a variety of basal birds, and suggest that extensively scaled feet might have appeared secondarily at an early stage in ornithuromorph evolution.
  • L. Xing, W. Persons, P. Currie
  • Environmental Science, Geography
    Evolution; international journal of organic evolution
  • 2013
The largest specimen of the four‐winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents, which offer unique insights into the ecology of nonavian dinosaurs early in the evolution of flight.
A fundamental avian wing-stroke provides a new perspective on the evolution of flight
This work presents the first comparison of wing-stroke kinematics of the primary locomotor modes (descending flight and incline flap-running) that lead to level-flapping flight in juvenile ground birds throughout development and puts forth an ontogenetic-transitional wing hypothesis that posits that the incremental adaptive stages leading to the evolution of avian flight correspond behaviourally and morphologically to transitional stages observed in ontogenetics forms.
The evolutionary continuum of limb function from early theropods to birds
It is emphasised that many false dichotomies or categories have been applied to theropod form and function, and sometimes, these impede research progress, and a combination of techniques that emphasises integration of neontological and palaeontological evidence and quantitative assessment of limb function cautiously applied with validated techniques and sensitivity analysis of unknown variables are needed.
Using physical models to study the gliding performance of extinct animals.
It is found that body orientation relative to the movement of air past the animal determines whether it is difficult or easy to maneuver, and therefore the design of gliders, both biological and man-made, is reviewed.
Pedal Claw Curvature in Birds, Lizards and Mesozoic Dinosaurs – Complicated Categories and Compensating for Mass-Specific and Phylogenetic Control
It is concluded that there is no strong mass-specific effect on claw curvature; furthermore, correlations between claw geometry and behaviour are consistent across disparate clades.
Rhetoric vs. reality: A commentary on “Bird Origins Anew” by A. Feduccia
A review of the full complement of facts pertaining to the avian origins debate is provided, motivated by a Perspectives article with numerous factual inaccuracies, to address the misplaced criticisms raised in that opinion paper.
Non‐avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China
The discovery of four-winged dinosaurs was suggested to provide strong evidence supporting the ‘tree-down’ hypothesis for the origin of avian flight, though in-depth analysis and more data are needed to confirm this.


Palaeontology: Leg feathers in an Early Cretaceous bird
A fossil of an enantiornithine bird from the Early Cretaceous period in China that has substantial plumage feathers attached to its upper leg (tibiotarsus) may be remnants of earlier long, aerodynamic leg feathers, in keeping with the hypothesis that birds went through a four-winged stage during the evolution of flight.
Four-winged dinosaurs from China
New evidence is provided suggesting that basal dromaeosaurid dinosaurs were four-winged animals and probably could glide, representing an intermediate stage towards the active, flapping-flight stage of proavians.
Cross-Testing Adaptive Hypotheses: Phylogenetic Analysis and the Origin of Bird Flight1
It is illustrated the cross-test of hypotheses of the evolution of several functions and adaptations related to the origin of bird flight with independently derived phylogenetic analysis, and shows that consilience does not support ideas that the close ancestors of birds were arboreal or evolved flight from the trees, nor that feathers evolved for flight.
Wing-Assisted Incline Running and the Evolution of Flight
  • K. Dial
  • Biology, Environmental Science
  • 2003
WAIR provides insight from behaviors observable in living birds into the possible role of incipient wings in feathered theropod dinosaurs and offers a previously unstudied explanation for the evolution of avian flight.
Functional Morphology in Vertebrate Paleontology
This paper presents a meta-analysis of the evolution of the hindlimb and tail from basal theropods to birds and the consequences of skull flattening in crocodilians and an analysis of the posture and gait of ceratopsian dinosaurs.
Exaptation-a missing term in the science of form
This work presents several examples of exaptation, indicating where a failure to concep- tualize such an idea limited the range of hypotheses previously available, and proposes a terminological solution to the problem of preadaptation.
Feathers of Archaeopteryx: Asymmetric Vanes Indicate Aerodynamic Function
Vanes in the primary flight feathers of Archaeopteryx conform to the asymmetric pattern in modern flying birds, suggesting that they evolved in the selective context of flight.