I am a PhD student in the Structure & Motion Laboratory, supervised by John Hutchinson, Jennifer Clack, Renate Weller, and Stephanie Pierce. My research focuses on the biomechanics of evolutionary transitions between water and land. Specifically, I am studying the role of the vertebral column in locomotion in two groups: stem tetrapods and basal crocodylomorphs.
I received my MA in biological and medical illustration at Johns Hopkins University in 2009. My masters thesis, Visualising Quadrupedal Launch in Pterosaurs, gave me experience modeling locomotion in extinct animals and also brought me into contact with researchers at the Royal Veterinary College. I joined the Structure & Motion Laboratory in 2009 as the research group's Scientific Illustrator, and began my PhD project in 2010.
I received the Lazendorf Prize for scientific illustration in 2009 and the Jackson School of Geosciences Student Travel Grant from the Society of Vertebrate Paleontology in 2011.
Illustration portfolio at www.juliamolnar.com
PhD project title: "Evolutionary transitions of the biomechanical functions of limbs and vertebrae from water to land and land to water: examples from early Tetrapoda and Crocodylomorpha."
Animals have repeatedly shifted between largely aquatic and largely terrestrial modes of life during their evolution. Although the biomechanics of the crania and limbs have received much attention from palaeontologists, the functional evolution of the axial skeleton remains relatively neglected. Yet vertebral mechanics are crucial for the understanding of locomotion and body support on land. The goal of my thesis is to test hypotheses about the locomotor behaviour of extinct tetrapods and to describe the morphological and mechanical changes of the axial skeleton that accompanied the water/land transition in two clades: stem tetrapods and crocodiles.
I will fulfil my project aims by building biomechanical models of the axial columns of an early tetrapod (Pederpes finneyae) and two early crocodylomorphs. They will be used to derive ranges of motion and to create animations of possible (vs. impossible) vertebral motions. To inform the models, I will collect and analyse data from extant species on the relationship between vertebral morphology and axial stiffness. Finally, I will compare the models’ biomechanical parameters and possible motions with kinematic and behavioural data from extant species and, where possible, to fossil footprints of the extinct taxa. The outcomes of this project are not only testing various locomotor reconstructions of these pivotal taxa, but also new methodologies for analysing vertebral form, function and evolution.
Pierce, SE, Ahlberg, PE, Hutchinson, JR, Molnar, JL, Sanchez, S, Tafforeau, P, Clack, JA. 2013. Vertebral architecture in the earliest stem tetrapods. Nature 493(7432). doi:10.1038/nature11825
Molnar, JL, Pierce, SE, Clack, JA, Hutchinson, JR. 2012. Idealized landmark-based geometric reconstructions of poorly preserved fossil material: a case study of an early tetrapod vertebra. Palaeontologia Electronica Vol. 15, Issue 1; 32,18p; palaeo-electronica.org/content/issue-1-2012-technical-articles/165-digital-fossil-restoration
Hutchinson JR, Bates KT, Molnar J, Allen V, Makovicky PJ. 2011. A computational analysis of limb and body dimensions in Tyrannosaurus rex with implications for locomotion, ontogeny and growth. PLoS One 6(10): e26037
Molnar, JL. How giant reptiles flew: Visualizing quadrupedal launch in pterosaurs.
Master’s thesis, Johns Hopkins University School of Medicine.
Blog post, Palaeontologica Electronica Blog, 2011
Presentation of research (informal) to prospective students and parents, Royal Veterinary College Open Day, 2011