This study confirms yet expands upon the results of the few previous sensitivity analyses performed on volumetric reconstructions of non-avian dinosaurs; body mass and inertial values are highly uncertain and show a wide range in plausible values, whilst the CM position is well constrained immediately in front and below the hip joint (Henderson 1999;
Hutchinson et al. 2007;
Bates et al. 2009). This analysis is the first to demonstrate the relatively modest effect of re-articulating poorly constrained osteological articulations on mass predictions. Increasing inter-vertebral spacing had a modest effect on total body mass and similarly little effect on CM position (as spacing anterior and posterior to the CM were increased), while the impact of altering the mediolateral orientation of the rib cage was largely negated by the necessary concomitant changes to the size of respiratory structures.
In addition to highlighting the importance of sensitivity analyses in soft tissue reconstructions of extinct taxa, these studies also provide the numerical data necessary for more robust evaluation of dinosaur anatomy. For example, whilst it is possible to postulate very large body masses for non-avian dinosaurs from volumetric reconstructions, these are only plausible if the skeleton is strong enough to withstand the forces generated during minimal locomotor exertion (e.g., walking, standing up). Although beyond the scope of this study, data generated from sensitivity analyses such as that reported here must subsequently be assessed in a functional context to further constrain plausible mass properties of non-avian dinosaurs.