Vertebral Allometry

The vertebral column, particularly the lumbar region, plays a pivotal role in high speed running in mammals. However, body size variation also places biomechanical constraints on the mammal skeleton.

I am interested in how size variation and locomotor demands have influenced vertebral evolution in mammals, and implications for their extinct ancestors.

My doctoral work examined vertebral allometry through growth (ontogenetic) and across clades (evolutionary) to tease apart complex factors shaping axial evolution

Ontogenetic allometry

Organsims are shaped by biomechanical and developmental constraints as they grow. 

I used longitudinal data from four species to contrast vertebral growth in species with different degrees of locomotory specialization. This study showed that evolutionary plasticity in growth was largely responsible for locomotor adaptations between species in the lumbar region. 

Evolutionary allometry

Mammals have undergone remarkable diversification in size through their evolutionary history, but what impact has this had on locomotor adaptations?

I compared allometric patterns in three clades specialized for running: felids (cats), bovids (antelope), and equids (horses). I found that the vertebral column adapts structurally to meet the challenges of increasing size in similar ways in all three groups, and that there is a trade off between running style and size in mammals.

Further comparisons to semi-aquatic seals revealed a much weaker influence of size, illustrating a release from some mechanical constraints of land associated with this ecological transition.

When applied to the extinct ancestors of horses, my data suggested very different running styles for small-bodied fossil equids.

Publications

Jones, K. E. 2016. New insights on equid locomotor evolution from the lumbar region of fossil horses. Proceedings of the Royal Society B: Biological Sciences. 283(1829).

Jones, K. E. and Pierce, S. E. 2015. Axial allometry in a neutrally buoyant environment: effects of the terrestrial-aquatic transition on vertebral scaling. Journal of Evolutionary Biology. 29(3):594-601.

Jones, K. E. 2015. Evolutionary allometry of lumbar shape in Felidae and Bovidae. Biological Journal of the Linnean Society. 116(3):721-740.

Jones, K. E. 2015. Preliminary data on the effect of osseous anatomy on ex vivo joint mobility in the equine thoracolumbar region. Equine Veterinary Journal. Early view.

Jones, K. E. 2015. Evolutionary allometry of the thoracolumbar centra in felids and bovids. Journal of Morphology.  267(7):818-831.

Katrina. E. Jones

Presidential Fellow

Interdisciplinary Centre for Ancient Life

University of Manchester

katrina.jones@manchester.ac.uk

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