Abstract
An animal's interaction with its environment is facilitated by the complex workings of the musculoskeletal system via movement. An animal's method of moving through its environment is fundamental to its way of life, how it finds food, shelter, escapes predators, interacts with conspecifics, disperses or migrates. Musculoskeletal anatomy is well correlated with ecology; craniodental morphology is highly adaptive with respect to feeding strategy, while variation in postcranial anatomy reflects adaptation principally for locomotion. Marsupials and monotremes fill a diverse range of ecological niches that are reflected in a great diversity of structural forms. Patterns in the form and function of animals can inform our understanding of the evolution of diverse groups and the relationships between them. In this chapter, we consider examples of musculoskeletal anatomy of marsupials and monotremes that highlight patterns of both phylogenetic history and evolutionary adaptation.