Convergence vs. Specialization in the ear region of moles (mammalia). (8th April 2015)

• Record Type: Journal Article
• Authors: Crumpton, Nick; Kardjilov, Nikolay; Asher, Robert J.
• Is Part Of: Journal of morphology. Volume 276:Number 8(2015:Aug.)
• Page Start: 900
• Page End: 914
• Publication Date: 2015-04-08
• Subjects: Morphology -- Periodicals; Physiology -- Periodicals; Anatomy -- Periodicals; 571.3
• DOI: 10.1002/jmor.20391
• Languages: English
• ISSNs: 0362-2525

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>We investigated if and how the inner ear region undergoes similar adaptations in small, fossorial, insectivoran‐grade mammals, and found a variety of inner ear phenotypes. In our sample, afrotherian moles (Chrysochloridae) and the marsupial <italic>Notoryctes</italic> differ from most other burrowing mammals in their relatively short radii of semicircular canal curvature; chrysochlorids and fossorial talpids share a relatively long interampullar width. Chrysochlorids are unique in showing a highly coiled cochlea with nearly four turns. Extensive cochlear coiling may reflect their greater ecological dependence on low frequency auditory cues compared to talpids, tenrecids, and the marsupial <italic>Notoryctes</italic>. Correspondingly, the lack of such extensive coiling in the inner ear of other fossorial species may indicate a greater reliance on other senses to enable their fossorial lifestyle, such as tactile sensation from vibrissae and Eimer's organs. The reliance of chrysochlorids on sound is evident in the high degree of coiling and in the diversity of its mallear types, and may help explain the lack of any semiaquatic members of that group. The simplest mallear types among chrysochlorids are not present in the basal‐most members of that clade, but all extant chrysochlorids investigated to date exhibit extensive cochlear coiling. The chrysochlorid ear region thus exhibits mosaic evolution; our data suggest that extensive coiling evolved in chrysochlorids prior to and independently of diversification in middle ear ossicle size and shape. J. Morphol. 276:900–914, 2015. © 2015 Wiley Periodicals, Inc.</p> </abstract>