Evolution of vertebral range of motion in Crocodylomorpha

Abstract

Crocodylomorphs have existed for ~235 million years, evolving an array of morphological diversity during this time, showing a variety of body sizes, diets, lifestyles, vertebral articulations, osteoderm arrangements, and locomotor modes. Reconstructing the evolution of this diversity is challenging because of their complexity, problems with fossil data, and the limited technology available to assess the biomechanics of that complexity, including the vertebral column of extinct and extant crocodylomorphs. This has changed in recent years with the introduction of new digital software (Autobend) which allows the three-dimensional biomechanics of joints in extinct and extant taxa to be studied, whilst being able to take soft tissues into account. This study uses these methods to reconstruct range of motion (ROM), the extent to which a part of the body can move around a joint, in the vertebral column, in crocodylomorph taxa from a range of time periods to see how ROM differs based on vertebral articulation, lifestyle, osteoderm coverage, and femur length. It is found that lateral bending in crocodylomorphs is mostly influenced by vertebral articulation and body length, two features which show great diversity within the clade, and highlight the significance of the evolution of the modern crocodilian bracing system. It also opens the door for further studies to be conducted, by looking into these features, to see if there are specific interclade variations.

Date of Award	2 Jul 2025
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Katrina Elizabeth Jones (Main Supervisor) & Russell Garwood (Co Supervisor)