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Article: Ontogeny of the Massospondylus labyrinth: implications for locomotory shifts in a basal sauropodomorph dinosaur

Palaeontology - Volume 62 Part 2 - Cover
Publication: Palaeontology
Volume: 62
Part: 2
Publication Date: March 2019
Page(s): 255 265
Author(s): James M. Neenan, Kimberley E. J. Chapelle, Vincent Fernandez, and Jonah N. Choiniere
Addition Information

How to Cite

NEENAN, J.M., CHAPELLE, K.E.J., FERNANDEZ, V., CHOINIERE, J.N. 2019. Ontogeny of the Massospondylus labyrinth: implications for locomotory shifts in a basal sauropodomorph dinosaur . Palaeontology, 62, 2, 255-265. DOI: /doi/10.1111/pala.12400

Author Information

  • James M. Neenan - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
  • James M. Neenan - Oxford University Museum of Natural History Parks Road Oxford OX1 3PW UK
  • Kimberley E. J. Chapelle - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
  • Kimberley E. J. Chapelle - School of Geosciences University of the Witwatersrand Johannesburg South Africa
  • Vincent Fernandez - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
  • Vincent Fernandez - European Synchrotron Radiation Facility Grenoble France
  • Jonah N. Choiniere - Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa

Publication History

  • Issue published online: 14 February 2019
  • Manuscript Accepted: 20 August 2018
  • Manuscript Received: 25 May 2018

Funded By

European Synchrotron Radiation Facility. Grant Number: ES275
National Research Foundation of South Africa's African Origins Platform. Grant Number: 98800
Leverhulme Trust Early Career Fellowship. Grant Number: ECF‐2017‐360
DST‐NRF Centre of Excellence in Palaeosciences. Grant Number: OP2015/11JC
Palaeontological Scientific Trust (PAST)
University of the Witwatersrand
ESRF project. Grant Number: ES275

Online Version Hosted By

Wiley Online Library
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Abstract

Ontogeny is a vital aspect of life history sometimes overlooked in palaeontological studies. However, the changing geometry of anatomical structures during growth can be informative regarding ecological and functional reconstructions. The inner ear, or labyrinth, is an ideal ontogenetic study system because it has a strong functional signal in its morphology that is linked to locomotor mode. Yet almost nothing is known about labyrinth development in dinosaurs. We quantified labyrinth scale and geometry through ontogeny in the Early Jurassic dinosaur Massospondylus carinatus, which has an exceptional fossil record and is hypothesized to have undergone a gait change, from quadrupedal juvenile to bipedal adult. To test whether this putative locomotor shift is reflected in labyrinth morphology, computed microtomography (μCT) and propagation phase‐contrast synchrotron radiation microtomography (PPC‐SRμCT) were used to obtain labyrinths from eight specimens, ranging from near‐hatchling to adult. Labyrinths grow substantially but scale with slight negative allometry compared to skull length throughout ontogeny, the first time this has been documented in dinosaurs. Geometric morphometric analysis of the labyrinth using a sliding semilandmark approach shows some morphological change through ontogeny, but little evidence supporting a locomotor shift. These results have implications for our understanding of sauropodomorph development and provide a better understanding of dinosaur locomotory evolution.

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