Model tests of gliding with different hindwing configurations in the four-winged dromaeosaurid Microraptor gui
- 25 January 2010
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (7), 2972-2976
- https://doi.org/10.1073/pnas.0911852107
Abstract
Fossils of the remarkable dromaeosaurid Microraptor gui and relatives clearly show well-developed flight feathers on the hind limbs as well as the front limbs. No modern vertebrate has hind limbs functioning as independent, fully developed wings; so, lacking a living example, little agreement exists on the functional morphology or likely flight configuration of the hindwing. Using a detailed reconstruction based on the actual skeleton of one individual, cast in the round, we developed light-weight, three-dimensional physical models and performed glide tests with anatomically reasonable hindwing configurations. Models were tested with hindwings abducted and extended laterally, as well as with a previously described biplane configuration. Although the hip joint requires the hindwing to have at least 20 degrees of negative dihedral (anhedral), all configurations were quite stable gliders. Glide angles ranged from 3 degrees to 21 degrees with a mean estimated equilibrium angle of 13.7 degrees, giving a lift to drag ratio of 4.1:1 and a lift coefficient of 0.64. The abducted hindwing model's equilibrium glide speed corresponds to a glide speed in the living animal of 10.6 m x s(-1). Although the biplane model glided almost as well as the other models, it was structurally deficient and required an unlikely weight distribution (very heavy head) for stable gliding. Our model with laterally abducted hindwings represents a biologically and aerodynamically reasonable configuration for this four-winged gliding animal. M. gui's feathered hindwings, although effective for gliding, would have seriously hampered terrestrial locomotion.Keywords
This publication has 21 references indexed in Scilit:
- A gliding lizard from the Early Cretaceous of ChinaProceedings of the National Academy of Sciences of the United States of America, 2007
- Biplane wing planform and flight performance of the feathered dinosaur Microraptor guiProceedings of the National Academy of Sciences of the United States of America, 2007
- Structure and function of hindlimb feathers in Archaeopteryx lithographicaPaleobiology, 2006
- Four-winged dinosaurs from ChinaNature, 2003
- Evolution of Vertebrate Flight: An Aerodynamic Model for the Transition from Gliding to Active FlightThe American Naturalist, 1985
- Body Proportions and Gliding Adaptations of Flying Squirrels (Petauristinae)Journal of Mammalogy, 1981
- Feathers of Archaeopteryx : Asymmetric Vanes Indicate Aerodynamic FunctionScience, 1979
- Archaeopteryx and the Origin of FlightThe Quarterly Review of Biology, 1974
- Dinosaur Physiology and the Origin of MammalsEvolution, 1971
- The Importance of the Nervous System in the Evolution of Animal FlightEvolution, 1952