Combined Biological Sciences Meeting

Department of Biochemistry & Molecular Biology, Bio21 Institute 
University of Melbourne   

Evolution of an arsenal: Diversification of the reptile venom system

The reptile venom system has been an area of long-standing interest and considerable conjecture, with some areas being particularly neglected; such as the predatory ecology of Varanus komodoensis (Komodo Dragon). We investigated the roles and potential interplay between cranial mechanics, toxic bacteria, and venom in V. komodoensis. Our analyses pointed to the presence of a sophisticated combined-arsenal killing apparatus. We found that the lightweight skull was relatively poorly adapted to generate high bite forces, but better adapted to resist high pulling loads. We rejected the popular notion regarding toxic bacteria utilisation. Instead, we demonstrated that the effects of deep wounds inflicted are potentiated through venom with toxic activities including anticoagulation and shock induction. Anatomical comparisons of V. komodoensis with Varanus (Megalania) prisca fossils suggested that the closely-related extinct giant was the largest venomous animal to have lived. These results are placed in their relative position within the larger picture through comparisons not only with other extant venomous lizards such as the gila monster but also in relation to the venomous snakes. This allowed for generalised statements to be made regarding the evolutionary selection pressures driving the changes in this integrated weapons system.

Click here for Dr Fry's biography