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Licensed Unlicensed Requires Authentication Published by De Gruyter October 27, 2020

Using a blind test to assess the discriminant power of morphological traits to distinguish between similar shrew species

  • Jacinto Román ORCID logo EMAIL logo , Felipe Siverio , Claudia Schuster , Juan Carlos Rivilla , Carmen Yuste , Luis Eduardo Biedma and Javier Calzada
From the journal Mammalia


The Canary Islands are home to a large variety of endemic fauna. The Canary shrew (Crocidura canariensis) has a distribution restricted to Fuerteventura, Lanzarote and the islets of Lobos and Montaña Clara. One of the main threats to the insular fauna is the arrival of exotic species. The greater white-toothed shrew (Crocidura russula) is an easily transportable animal and a potential competitor for C. canariensis. Therefore, C. russula should be taken into account in the management protocols for invasive species. One of the most easily applicable techniques for detecting shrews is the analysis of pellets. This study aims to assess which morphological characters are diagnostic and easy to use when identifying both species of shrews. For this purpose, a blind specific assignment has been made using seven previously described characters and another three added in the present study. The results show that the observer’s experience did not improve the correct identification rate and that only three of the evaluated characters have a high discriminant capacity. Finally, it was found that the combined use of the maximum number of characters and the identification by two independent observers reduces the probability of making a mistake in the determination to minimum values.

Corresponding author: Jacinto Román, Department of Conservation Biology, Doñana Biological Station, CSIC, C. Américo Vespucio 26, 41092Sevilla, Spain, E-mail:


The authors would like to thank Beneharo Rodríguez (GOHNIC) for the cession of owl pellets collected on Montaña Clara islet. Logistic and technical support were provided by scientific collection of Doñana Biological Station ICTS-RBD.

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.


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Supplementary Material

The online version of this article offers supplementary material (

Received: 2020-04-21
Accepted: 2020-09-21
Published Online: 2020-10-27
Published in Print: 2021-03-26

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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