Ariel Marcy is doing her PhD on Australian rodent evolution. Despite being recent arrivals to Australia, native rodents achieve distinction as the continent’s most speciose yet least studied mammalian group. Using 3D geometric morphometrics, she aims to catalogue the diversity of Australian rodents and use this new knowledge to investigate several aspects of rodent evolution since the Pleistocene. She aims to use her findings to improve understanding of mammalian evolution and how developmental traits, environment, geography, and climate interact to produce macro-evolutionary diversity patterns. As an undergraduate at Stanford University, I used GIS to demonstrate that differences in soil type and digging adaptations helped explain the unusual species distribution of North American pocket gophers (genus Thomomys), which I then followed up with a paper on how these gophers adapt to soil conditions through different evolutionary avenues (watch hermovie here!). I am also founder of educational game company, STEAM Galaxy Studios and designed our flagship educational game, Go Extinct! It’s a go-fish style card game that teaches humans 8 and up how land vertebrates are related, the evidence scientists use to classify them, and how to read evolutionary trees.
This year, Cruise will be undertaking an honours project investigating the evolution of mandible (lower jaw) shape within vombatiforms (including wombats and koalas). Wombats and koalas are some of the most iconic fauna of Australia, and also some of the most interesting evolutionarily. Today, vombatiforms are comprised only of four extant species, but represent a far more diverse, now extinct radiation beginning in the late Oligocene (including Diprotodon, the largest marsupial to ever live!). Koalas are browsing specialists on Eucalyptus while wombats are grazers, and extinct vombatiforms are thought to have fallen along this browser-grazer spectrum. In this project, Cruise will be using landmarking techniques on 3D skull reconstructions of wombats, koalas, and extinct vombatiforms to identify differences in their mandible morphology. From this, I aim to understand how mandible shape evolved throughout the vombatiforms, and how this relates to the function of the mandible and the ecology of the species.
Laura is undertaking an honours project investigating the evolution and development of the mammalian middle ear. The delicate sound-conducting middle ear ossicles present in mammals today evolved from load-bearing jaw bone elements in mammalian ancestors. Current theories propose that the development of the middle ear as a marsupial grows from neonate to adult recapitulates the successive stages of middle ear evolution. Laura is creating comprehensive 3D reconstructions of the bony elements and soft tissue of the mammalian middle ear and jaw adductor muscles using CT scans of marsupial heads at different life stages, to examine if and how these components change throughout development, and if this development recapitulates the evolution of the middle ear. Laura is also investigating the power of a recently developed STABILITY staining protocol used on the specimens, which allows soft tissue to be visible in CT scans with minimal distortion and damage to the specimen itself.
Past lab members
Alison did her honours on fine-tuning a DiceCT staining protocol for brain imaging in CT scans and getting the first quantitative volumetric growth data from marsupial brain partitions, based on virtual 3D reconstruction.
Kate did her honours on bandicoot limb morphology, to try and unravel the evolutionary story of marsupial limbs and why they failed to diversify into structures like that of the placentals (such as hooves, wings and flippers). Kates work suggests that the unusual birth mode of bandicoots at least partially lifts the developmental constraint off the bandicoot forelimbs, permitting them to become more diverse in structure than other marsupials – the paper is accepted and will come out soon, so watch this space!