Lower rotational inertia and larger leg muscles indicate more rapid turns in tyrannosaurids than in other large theropods

PeerJ

article

Eric Snively¹  Haley O’Brien²  Donald M. Henderson³  Heinrich Mallison⁴  Lara A. Surring³  Michael E. Burns⁵  Thomas R. Holtz Jr⁶  Anthony P. Russell⁸  Lawrence M. Witmer⁹  Philip J. Currie^1,10  Scott A. Hartman^1,11  John R. Cotton^1,12 

[1] Department of Biology, University of Wisconsin-La Crosse;Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences;Royal Tyrrell Museum of Palaeontology;Museum fur Naturkunde;Department of Biology, Jacksonville State University;Department of Geology, University of Maryland, College Park;Department of Paleobiology, National Museum of Natural History;Department of Biological Sciences, University of Calgary;Department of Biomedical Sciences, Ohio University;Department of Biological Sciences, University of Alberta;Department of Geoscience, University of Wisconsin-Madison;Department of Mechanical Engineering, Ohio University

关键词: Theropoda;    Biomechanics;    Agility;    Phylogenetic ANCOVA;    Tyrannosauridae;    Predation;   

DOI  :  10.7717/peerj.6432

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Synopsis Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods. Methods To compare turning capability in theropods, we regressed agility estimates against body mass, incorporating superellipse-based modeled mass, centers of mass, and rotational inertia (mass moment of inertia). Muscle force relative to body mass is a direct correlate of agility in humans, and torque gives potential angular acceleration. Agility scores therefore include rotational inertia values divided by proxies for (1) muscle force (ilium area and estimates of m. caudofemoralis longus cross-section), and (2) musculoskeletal torque. Phylogenetic ANCOVA (phylANCOVA) allow assessment of differences in agility between tyrannosaurids and non-tyrannosaurid theropods (accounting for both ontogeny and phylogeny). We applied conditional error probabilities a(p) to stringently test the null hypothesis of equal agility. Results Tyrannosaurids consistently have agility index magnitudes twice those of allosauroids and some other theropods of equivalent mass, turning the body with both legs planted or pivoting over a stance leg. PhylANCOVA demonstrates definitively greater agilities in tyrannosaurids, and phylogeny explains nearly all covariance. Mass property results are consistent with those of other studies based on skeletal mounts, and between different figure-based methods (our main mathematical slicing procedures, lofted 3D computer models, and simplified graphical double integration). Implications 400 kg), toothed dinosaurian predator niches in their habitats.

【 授权许可】

CC BY