Logo image
Back
Ontogenetic variation in the crocodylian vestibular system
Journal article   Peer reviewed

Ontogenetic variation in the crocodylian vestibular system

Julia A. Schwab, Mark T. Young, Stig A. Walsh, Lawrence M. Witmer, Yanina Herrera, Christopher A. Brochu, Ian B. Butler and Stephen L. Brusatte
Journal of Anatomy, Vol.240(5), pp.821-832
2021
DOI: 10.1111/joa.13601
url
https://www.research.ed.ac.uk/en/publications/8ad85e02-ae0b-473a-b943-a34af03b8fe0View
Open Access

Abstract

Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known about the vestibular system of the inner ear. Here we use 30 high-resolution computed tomography (CT) scans and three-dimensional geometric morphometrics to investigate the size and shape changes of crocodylian endosseous labyrinths throughout ontogeny, across four stages (hatchling, juvenile, subadult and adult). We find two major patterns of ontogenetic change. First, the labyrinth increases in size during ontogeny, with negative allometry in relation to skull size. Second, labyrinth shape changes significantly, with hatchlings having shorter semicircular canal radii, with thicker diameters and an overall dorsoventrally shorter labyrinth than those of more mature individuals. We argue that the modification of the labyrinth during crocodylian ontogeny is related to constraints imposed by skull growth, due to fundamental changes in the crocodylian braincase during ontogeny (e.g. verticalisation of the basicranium), rather than changes in locomotion, diet, or other biological functions or behaviours.

Details

Metrics

34 Record Views
18 Times Cited - Web of Science
Logo image