Functional morphology and evolution of marsupial moles (Marsupialia: Notoryctemorphia)

Natalie Warburton

Research output: ThesisDoctoral Thesis

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Abstract

Marsupial moles (genus Notoryctes) are the most highly specialised burrowing marsupials. The specialisations of the appendicular musculo-skeletal system of the marsupial moles are extensive and widespread; the major alterations are concentrated in, but not restricted to, the forelimb. Many of the derived features of the muscular system appear to be adaptations for improving the mechanical advantage of the limbs for burrowing. A number of the specialisations of the muscular system of the marsupial moles are convergent with those previously documented in other fossorial mammals, including golden moles, rodents and armadillos. There are, however, a number of unique specialisations of the musculo-skeletal system of Notoryctes. The functional morphology of the locomotor apparatus of marsupial moles is interpreted on the basis of the descriptions of the anatomy of the skeletal and muscular systems. The burrowing technique of the marsupial moles is a modified form of the parasagittal digging method that is used by other fossorial mammals, such as golden moles, armadillos and some rodents including pocket gophers. Differences in the functional morphology of the hindlimb between marsupial moles and other fossorial mammals are a reflection of the fact that marsupial moles do not construct permanent open burrow systems, but instead constantly dig through loose soil, backfilling as they progress. The functional morphology of the tail is uniquely specialised in the marsupial moles to function as the fifth limb during the pentapedal burrowing locomotion of marsupial moles. The remains of Miocene fossil marsupial mole, while clearly pleisiomorphic with respect to the appendicular skeletal morphology of modern notoryctids, demonstrate a high degree of specialisation for digging. It is hypothesised that the Miocene marsupial mole was already substantially specialised for a fossorial lifestyle, and thus pre-adapted for a subterranean lifestyle developed in correlation with the desertification of the Australian continent. Phylogenetic affinities of marsupial moles within the Marsupialia have long been enigmatic. While specialisation of the musculo-skeletal system have been so widespread as to obscure almost any phylogenetically relevant patterns, there is some evidence to support an association between notoryctids and peramelid bandicoots. Interspecific differences between the two species of marsupial moles, Notoryctes typhlops and N. caurinus, are minor but do support the separation of the two species.
Original languageEnglish
QualificationDoctor of Philosophy
Publication statusUnpublished - 2003

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