Geometric Morphometrics (GM)

GM gives us a way to compare the shape of different things using maths and computers. What exactly do I mean by shape though? Well, imagine if you and all your friends draw a simple triangle on separate pieces of paper. Each drawing is a little different—one triangle is bigger, another is more tilted, and they all have slightly different lengths of their sides. But you want to compare the shapes of all the triangles, not their size or position on the paper.

We can use a clever little trick called Procrustes Superimposition that helps us compare the shapes of the triangles, by removing differences in size, position, and rotation. This is done by lining the triangles up so they are exactly on top of each other, then resizing them to all be the same size, and finally rotating them to match each other a closely as possible. After doing all this, what we have left is the shape that we can analyse and compare!

GM is like combining Connect-the-Dots with Tangrams!

To see how I apply GM to skulls, see video link (coming soon)

Anatomical Animations

I use a combination of digital modelling and animation techniques from Blender software, combined with advanced PowerPoint presentation design, to generate fun and engaging imagery for communicating complex ideas.

Publications

Mitchell DR, Wroe S, Martin M, Weisbecker V (2025). Testing hypotheses of skull function with comparative finite element analysis: three methods reveal contrasting results. Journal of Experimental Biology jeb-249747.

Mitchell DR, Potter S, Eldridge MD, Martin M, Weisbecker V (2024). Functionally mediated cranial allometry evidenced in a genus of rock-wallabies. Biology letters 20(3): 20240045.

Mitchell DR, Sherratt E, Weisbecker V (2024). Facing the facts: adaptive trade‐offs along body size ranges determine mammalian craniofacial scaling. Biological Reviews 99(2): 496-524.

Mitchell DR, Ledogar JA, Andrew D, Mathewson I, Weisbecker V, Vernes K (2024). The mechanical properties of bettong and potoroo foods. Australian Mammalogy 46(3): AM24006.

Marcy AE, Mitchell DR, Guillerme T, Phillips MJ, Weisbecker V (2024). Beyond CREA: Evolutionary patterns of non‐allometric shape variation and divergence in a highly allometric clade of murine rodents. Ecology and Evolution 14(7): e11588.

Kirchhoff CA, Cooke SB, Gomez JC, Mitchell DR, Stein T, Terhune CE (2024). Variation in Craniodental Pathologies Among Cercopithecoid Primates. American Journal of Primatology 86(11): e23681.

Fiorenza L, Mitchell DR, Kullmer O (2024). Pongo's ecological diversity from dental macrowear analysis. American Journal of Biological Anthropology 185(4): e25031.

Mitchell DR, Cairns SC, Körtner G, Bradshaw CJ, Saltré F, Weisbecker V (2023). Differential developmental rates and demographics in Red Kangaroo (Osphranter rufus) populations separated by the dingo barrier fence. Journal of Mammalogy 104(5): 929-940.

Sansalone G, Profico A, Wroe S, Allen K, Ledogar J, Ledogar S, Mitchell DR, Mondanaro A, Melchionna M, Castiglione S, Serio C, Raia P (2023). Homo sapiens and Neanderthals share high cerebral cortex integration into adulthood. Nature Ecology & Evolution 7(1): 42-50.

Terhune CE, Mitchell DR, Cooke SB, Kirchhoff CA, Massey JS (2022). Temporomandibular joint shape in anthropoid primates varies widely and is patterned by size and phylogeny. The Anatomical Record 305(9): 2227-2248.

Van Heteren AH, Wroe S, Tsang LR, Mitchell DR, Ross P, Ledogar JA, Attard MRG, Sustaita D, Clausen P, Scofield RP, Sansalone G (2021). New Zealand's extinct giant raptor (Hieraaetus moorei) killed like an eagle, ate like a condor. Proceedings of the Royal Society B 288(1964): 20211913.

Mitchell DR, Wroe S, Ravosa MJ, Menegaz RA (2021). More challenging diets sustain feeding performance: Applications toward the captive rearing of wildlife. Integrative Organismal Biology 3(1): obab030.

Mitchell DR, Kirchhoff CA, Cooke SB, Terhune CE (2021). Bolstering geometric morphometrics sample sizes with damaged and pathologic specimens: Is near enough good enough?. Journal of Anatomy 238(6): 1444-1455.

Romero AN, Mitchell DR, Cooke SB, Kirchhoff CA, Terhune CE (2022). Craniofacial fluctuating asymmetry in gorillas, chimpanzees, and macaques. American Journal of Biological Anthropology 177(2): 286-299.

Mitchell DR, Sherratt E, Sansalone G, Ledogar JA, Flavel RJ, Wroe S (2020). Feeding biomechanics influences craniofacial morphology at the subspecies scale among Australian Pademelons (Macropodidae: Thylogale). Journal of Mammalian Evolution 27: 199-209.

Sansalone G, Allen K, Ledogar JA, Ledogar S, Mitchell DR, Profico A, Castiglione S, Melchionna M, Serio C, Mondanaro A, Raia P, Wroe S (2020). Variation in the strength of allometry drives rates of evolution in primate brain shape. Proceedings of the Royal Society B 287(1930): 20200807.

Hart LJ, Bell PR, Smith ET, Mitchell DR, Brougham T, Salisbury SW (2021). A probable skeleton of Isisfordia (Crocodyliformes) and additional crocodyliform remains from the Griman Creek Formation (Cenomanian, New South Wales, Australia). Journal of Paleontology 95(2): 351-366.

Mitchell DR (2019). The anatomy of a crushing bite: the specialised cranial mechanics of a giant extinct kangaroo. PLoS One 14(9): e0221287.

Mitchell DR, Wroe S (2019). Biting mechanics determines craniofacial morphology among extant diprotodont herbivores: dietary predictions for the giant extinct short-faced kangaroo, Simosthenurus occidentalis. Paleobiology 45(1): 167-181.

Mitchell DR, Sherratt E, Ledogar JA, Wroe S (2018). The biomechanics of foraging determines face length among kangaroos and their relatives. Proceedings of the Royal Society B 285(1881): 20180845.

Mitchell DR (2018). The cranial mechanics of herbivory in kangaroos and relatives: an integrated geometric morphometric and finite element approach. PhD Thesis. University of New England, Armidale, Australia.

Mitchell DR, Reid A (2017). 'Octopus kapalae', sp. nov.: A new species of 'Octopus' from South-eastern Australia. Proceedings of the Linnean Society of New South Wales 139: 57-67.

Mitchell DR, Leung TL. (2016). Sharing the load: a survey of parasitism in the invasive freshwater pulmonate, Physa acuta (Hygrophila: Physidae) and sympatric native snail populations. Hydrobiologia 766: 165-172.

Allen L, Mitchell DR (2016). A new record of the Swamp Wallaby'Wallabia bicolor (Desmarest, 1804) (Marsupialia: Macropodinae) in South Australia. The South Australian Naturalist 90(1): 17-23.