2013/04/01 by Bianca Hohn-Schulte, Holger Preuschoft, U. Witzel +1 · 1 citation
Earth and Planetary Sciences · Environmental Science · Engineering · #Paleontology and Evolutionary Biology #Evolution and Paleontology Studies #Ichthyology and Marine Biology #Quadrupedalism #Trunk #Vertebral column #Geology #Anatomy #Biomechanics #Terrestrial locomotion #Forelimb #Bending #Tetrapod (structure) #Compression (physics) #Structural engineering #Biology #Materials science #Paleontology #Engineering #Ecology
paper · doi:10.1080/08912963.2012.755677
openalex publication_date 2013/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
The fossil Tiktaalik roseae from the Late Devonian induces clear definition of the biomechanical and functional preconditions for a terrestrial lifestyle including quadrupedal standing and locomotion on limbs. Therefore, we determined the internal stresses in this model organism under the influence of gravity using the finite element method. Stress patterns during symmetrical two-forelimb support result from bending of trunk and neck. During asymmetrical one-forelimb support, as occurs during terrestrial locomotion, torsional stresses are higher than those caused by bending. The observed patterns of compressive stresses correspond well with the arrangement of compression-resistant materials: vertebral column, shoulder girdle and ribs. The tensile stresses are in accordance with the arrangement of longitudinal and oblique muscles forming the body wall. Torsional stresses concentrate along the periphery of the trunk, leaving its cavity free from mechanical stresses. Theoretical mechanics indicate that the flat skull and the mobility of the neck were advantageous for lateral snapping, similar to crocodiles. The same movement on land requires sprawling and flexed forelimbs. Our results can be interpreted as explanations for the tetrapod bauplan as well as confirmation and refinement of existing hypotheses about the lifestyle at the border between water and land of this early predecessor of terrestrial tetrapods.