Oral presentation- Open Session 12th International Mammalogical Congress

Deep time to conservation: Quantifying shape variation within the last four vombatiform species through 3D geometric morphometrics. (#317)

Vera Weisbecker 1 , Hyab Mehari Abraha 1 , Claire Terhune 2 , Stephen Johnston 1 , Alana Sharp 3 , Cruise Speck 1 , Olga Panagiotopoulou 1
  1. University of Queensland, St. Lucia, Queensland, Australia
  2. Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, United States of America
  3. Division of Biosciences , University College London, London, United Kingdom

The koala and three species of wombat are the only survivors of the diverse clade of Vombatiformes, including many gigantic, herbivorous megafauna species. They are also specialized herbivores, which makes them susceptible to environmental change. Understanding the relationship between wombat/koala cranial shape and feeding ecology allows an assessment of their adaptability to current environmental change, and a chance to extrapolate on the evolution of the giant herbivorous Vombatiforms. Here, we use 3D geometric morphometric analysis to assess intra-and inter-specific cranial shape diversity in all three wombat species and the koala (n=29-31/each species). Not unexpectedly, principal component analysis and 3D warp visualizations of PC space revealed a dichotomy between broad and blunt crania of wombats and narrow, pincer-like snouts in koalas. However, koalas showed far less shape disparity than wombats, possibly due to their more extreme specialization on eucalypt folivory. All wombat species showed substantial intra-specific cranial shape variation, which unexpectedly was neither explainable by allometry nor broad geographical categories. The closely-related Northern and Southern hairy-nosed wombats (NHNW/SHNW) do not overlap much in principal component space, with SHNWs showing some shape similarity (teardrop-shaped, more procumbent skulls) with common wombats. This is unexpected because SHNWS feed on harder vegetation and live in more arid habitats than NHNWs and common wombats. From the lack of clear diet-related shape differences, we conclude that either wombat crania are extremely susceptible to localized (dietary) environments, or is not selected for feeding efficiency; extended sampling of captive specimens might provide an avenue of testing these alternatives.