Testing convergent and parallel adaptations in talpids humeral mechanical performance by means of geometric morphometrics and finite element analysis

Authors

  • P. Piras,

    Corresponding author
    1. Center for Evolutionary Ecology, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    2. Dipartimento di Scienze Geologiche, Università Roma Tre, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    • Center for Evolutionary Ecology, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
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  • G. Sansalone,

    1. Center for Evolutionary Ecology, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    2. Dipartimento di Scienze Geologiche, Università Roma Tre, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    3. Dipartimento di Biologia e Biotecnologia “Charles Darwin”, “Sapienza” Università di Roma,Via Borelli 50, I-00161 Rome, Italy
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  • L. Teresi,

    1. LaMS - Modelling & Simulation Lab Università Roma Tre, Via Corrado Segre, 6 I-00146 Roma, Italy
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  • T. Kotsakis,

    1. Center for Evolutionary Ecology, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    2. Dipartimento di Scienze Geologiche, Università Roma Tre, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
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  • P. Colangelo,,

    1. Dipartimento di Biologia e Biotecnologia “Charles Darwin”, “Sapienza” Università di Roma,Via Borelli 50, I-00161 Rome, Italy
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  • A. Loy

    1. Center for Evolutionary Ecology, Largo San Leonardo Murialdo 1, 00146 Roma, Italy
    2. Environmetrics Lab, Dipartimento STAT, Università del Molise, Pesche I-86090, Italy
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Abstract

The shape and mechanical performance in Talpidae humeri were studied by means of Geometric Morphometrics and Finite Element Analysis, including both extinct and extant taxa. The aim of this study was to test whether the ability to dig, quantified by humerus mechanical performance, was characterized by convergent or parallel adaptations in different clades of complex tunnel digger within Talpidae, that is, Talpinae+Condylura (monophyletic) and some complex tunnel diggers not belonging to this clade. Our results suggest that the pattern underlying Talpidae humerus evolution is evolutionary parallelism. However, this insight changed to true convergence when we tested an alternative phylogeny based on molecular data, with Condylura moved to a more basal phylogenetic position. Shape and performance analyses, as well as specific comparative methods, provided strong evidence that the ability to dig complex tunnels reached a functional optimum in distantly related taxa. This was also confirmed by the lower phenotypic variance in complex tunnel digger taxa, compared to non-complex tunnel diggers. Evolutionary rates of phenotypic change showed a smooth deceleration in correspondence with the most recent common ancestor of the Talpinae+Condylura clade. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.

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