Fossil Record 17(1): 33-39, doi: 10.5194/fr-17-33-2014
Osteoderm distribution has low impact on the centre of mass of stegosaurs
expand article infoH. Mallison
‡ Museum für Naturkunde – Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
Open Access
It has been hypothesized that the pronounced differences of stegosaurhumeral shapes, with large forms having more slender and small forms havingmore robust humeri, may be explained by a difference in relative centre ofmass (COM) placement caused by differing distributions of osteoderms. Totest this hypothesis, digital 3-D models of the bones and osteoderms of theTanzanian stegosaur Kentrosaurus aethiopicus and of the NorthAmerican stegosaur Stegosaurus armatus were used to createa 3-D computer-aided design life reconstruction. On these models osteodermplacement was varied drastically, recreating both existing and hypotheticalforms. These models show that COM position varies somewhat with realisticosteoderm distributions, but insufficiently to explain major differences inhumeral shape. The uniform weight distribution between forelimbs and hindlimbs found between the two taxa also casts doubt on the hypothesis thatdifferences in relative COM position caused by other factors than osteodermdistribution can explain differences in humeral robustness.