A comparison of the external morphology of the membranous inner ear in elasmobranchs

Authors

  • Carla Evangelista,

    Corresponding author
    1. Sensory Neurobiology Group, The School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
    • Queensland Brain Institute, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
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  • Morena Mills,

    1. Sensory Neurobiology Group, The School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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  • Ulrike E. Siebeck,

    1. Sensory Neurobiology Group, The School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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  • Shaun P. Collin

    1. Sensory Neurobiology Group, The School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
    Current affiliation:
    1. School of Animal Biology, The University of Western Australia, Crawley 6009, Western Australia, Australia
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Abstract

Studies on the elasmobranch inner ear have focused predominantly on a small group of sharks, particularly, carcharhinids. As a result, subsequent studies in other species have subdivided species into two main groups: those typical and those atypical of carcharhinid sharks. This study proposes a different set of inner-ear morphology groupings to those previously suggested. The inner ears from 17 species of elasmobranchs (representing both sharks and rays) are examined in this study and based on morphometric data some groups include both rays and sharks. Four groups are now proposed based predominantly on the shape and dimensions of the membranous otoconial organs, and characteristics of the semicircular canals. Evident morphological differences between the ear types belonging to the new groups include the membranes of the semicircular canals being bound to the otoconial organs in some species, while only being connected via the canal ducts in others, as well as clear variation present in saccular organ size. Previous studies examining variation in the inner ear have attributed differences to either phylogeny or functional significance. Results from this study suggest that neither phylogeny nor feeding strategy solely accounts for the morphological diversity present in the external morphology of the elasmobranch inner ear. J. Morphol., 2010. © 2010 Wiley-Liss, Inc.

Ancillary