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Relationships of mass properties and body proportions to locomotor habit in terrestrial Archosauria

Peter J. Bishop, Karl T. Bates, Vivian R. Allen, Donald M. Henderson, Marcela Randau and John R. Hutchinson
Relationships of mass properties and body proportions to locomotor habit in terrestrial Archosauria
Paleobiology (November 2020) 46 (4): 550-568


Throughout their 250 Myr history, archosaurian reptiles have exhibited a wide array of body sizes, shapes, and locomotor habits, especially in regard to terrestriality. These features make Archosauria a useful clade with which to study the interplay between body size, shape, and locomotor behavior, and how this interplay may have influenced locomotor evolution. Here, digital volumetric models of 80 taxa are used to explore how mass properties and body proportions relate to each other and locomotor posture in archosaurs. One-way, nonparametric, multivariate analysis of variance, based on the results of principal components analysis, shows that bipedal and quadrupedal archosaurs are largely distinguished from each other on the basis of just four anatomical parameters (p < 0.001): mass, center of mass position, and relative forelimb and hindlimb lengths. This facilitates the development of a quantitative predictive framework that can help assess gross locomotor posture in understudied or controversial taxa, such as the crocodile-line Batrachotomus (predicted quadruped) and Postosuchus (predicted biped). Compared with quadrupedal archosaurs, bipedal species tend to have relatively longer hindlimbs and a more caudally positioned whole-body center of mass, and collectively exhibit greater variance in forelimb lengths. These patterns are interpreted to reflect differing biomechanical constraints acting on the archosaurian Bauplan in bipedal versus quadrupedal groups, which may have shaped the evolutionary histories of their respective members.

ISSN: 0094-8373
EISSN: 1938-5331
Serial Title: Paleobiology
Serial Volume: 46
Serial Issue: 4
Title: Relationships of mass properties and body proportions to locomotor habit in terrestrial Archosauria
Affiliation: Royal Veterinary College, Structure and Motion Laboratory, Hatfield, United Kingdom
Pages: 550-568
Published: 202011
Text Language: English
Publisher: Paleontological Society, Lawrence, KS, United States
References: 103
Accession Number: 2021-003290
Categories: Vertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables
Secondary Affiliation: University of Liverpool, GBR, United KingdomRoyal Tyrrell Museum of Palaeontology, CAN, CanadaNatural History Museum, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Abstract, Copyright, The Paleontological Society. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2021
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