Balmori de la Puente, AlfonsoNores, CarlosRomán, JacintoFernández González, AngelAymerich i Boixader, PereGosàlbez i Noguera, JoaquimEscoda, LídiaCastresana Ruiz-Carrillo, José Ignacio2020-07-202020-07-202019Balmori-de la Puente A, Nores C, Román J, Fernández-González A, Aymerich P, Gosálbez J, Escoda L, Castresana J. Size increase without genetic divergence in the Eurasian water shrew Neomys fodiens. Sci Rep. 2019; 9(1):17375. DOI: 10.1038/s41598-019-53891-y2045-2322http://hdl.handle.net/10230/45130When a population shows a marked morphological change, it is important to know whether that population is genetically distinct; if it is not, the novel trait could correspond to an adaptation that might be of great ecological interest. Here, we studied a subspecies of water shrew, Neomys fodiens niethammeri, which is found in a narrow strip of the northern Iberian Peninsula. This subspecies presents an abrupt increase in skull size when compared to the rest of the Eurasian population, which has led to the suggestion that it is actually a different species. Skulls obtained from owl pellets collected over the last 50 years allowed us to perform a morphometric analysis in addition to an extensive multilocus analysis based on short intron fragments successfully amplified from these degraded samples. Interestingly, no genetic divergence was detected using either mitochondrial or nuclear data. Additionally, an allele frequency analysis revealed no significant genetic differentiation. The absence of genetic divergence and differentiation revealed here indicate that the large form of N. fodiens does not correspond to a different species and instead represents an extreme case of size increase, of possible adaptive value, which deserves further investigation.application/pdfeng© The Author(s) 2019. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.info:eu-repo/semantics/articlehttp://dx.doi.org/10.1038/s41598-019-53891-yEvolutionary ecologyEvolutionary geneticsPhylogeneticsPopulation geneticsinfo:eu-repo/semantics/openAccess