RESHAPING THE PAST: INVESTIGATING GEOLOGICAL DEFORMATION IN †DIICTODON USING 3D GEOMETRIC MORPHOMETRICS

Fossils are deformed by taphonomic and geological compression, potentially obscuring original shape and intraspecific variation that could reveal insights into sexual dimorphism, development, and microevolutionary processes indicated by asymmetry. Systematic quantitative studies are therefore needed to explore the influence of taphonomy on palaeontological analyses and determine the possibility of perceiving original biological shape or asymmetry. †Diictodon, a basal therapsid, is a model system for investigating these questions because it is abundant and well preserved, representing approximately half of all vertebrate fossils from the Late Permian Karoo Basin of South Africa. Here, we apply 3D geometric morphometrics to study a large dataset of 76 †Diictodon crania. We classify crania into five deformation styles, which form distinct clusters in multivariate space. Further, we examine the individual contributions of deformation style to intraspecific asymmetry and their effects on the capacity to conduct retrodeformation to restore original shape. In addition, we suggest the possibility that intraspecific variation within other fossil species may represent geological deformation rather than original biological disparity.