White Rose University Consortium logo
University of Leeds logo University of Sheffield logo York University logo

Phylogeographic and morphometric studies on the Eurasian pygmy shrew Sorex minutus: insights into its evolutionary history and postglacial colonisation in Europe

Vega Bernal, Rodrigo Rafael (2010) Phylogeographic and morphometric studies on the Eurasian pygmy shrew Sorex minutus: insights into its evolutionary history and postglacial colonisation in Europe. PhD thesis, University of York.

[img] Text
Available under License Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 UK: England & Wales.

Download (13Mb)


Here, I investigate the phylogeography and morphology of the Eurasian pygmy shrew Sorex minutus, searching for significantly differentiated lineages, colonisation routes and demographic parameters that would explain the effects of the Quaternary glaciations on the current distribution of the species. I also explore the genetic and morphological diversity and origin of pygmy shrew populations in the British Isles, particularly focusing on Ireland and the Orkney islands. Mitochondrial and nuclear DNA markers were used for the phylogeographic analyses, and a geometric morphometrics approach was implemented on mandible and skull samples. There was an evident phylogeographic structure across Eurasia consistent with occurrence of southern glacial refugia, and there were two distinct lineages in Northern-Central Europe and near the Pyrenees supporting the existence of northern glacial refugia through the characteristics of their distribution and population expansion. Haplotypes from Britain belonged to these two northern lineages, with the Pyrenean lineage forming a peripheral ‘Celtic fringe’. I show that it is most likely that pygmy shrews on both Ireland and Orkney were introduced by humans from mainland British Celtic fringe rather than further afield, even though there is a haplotype found in Northern Spain identical to one in Ireland. Mandible size increased noticeably with decreasing latitude, but skulls showed no evident trend in size variation. Shape variation was significant but modest when analysing the sample divided into phylogeographical groups. However, the samples from different islands within the British Isles show that island evolution played an important role in morphological diversity, with mandible and skull shape divergence on small islands and low genetic diversity. These results notably expanded previous findings and indicate that S. minutus is an excellent model for understanding the effects of climate change on biological diversity, colonisation and differentiation in refugia, and island evolution, useful for the conservation of genetic and morphological diversity.

Item Type: Thesis (PhD)
Keywords: Phylogeography, geometric morphometrics, Sorex minutus, pygmy shrew, colonisation, glacial refugia, cytochrome b, Y chromosome introns, nuclear gene, Europe, Britain, Ireland, island
Academic Units: The University of York > Biology (York)
Identification Number/EthosID: uk.bl.ethos.533462
Depositing User: Mr Rodrigo Rafael Vega Bernal
Date Deposited: 19 Oct 2010 15:45
Last Modified: 08 Sep 2016 12:19
URI: http://etheses.whiterose.ac.uk/id/eprint/1039

You do not need to contact us to get a copy of this thesis. Please use the 'Download' link(s) above to get a copy.
You can contact us about this thesis. If you need to make a general enquiry, please see the Contact us page.

Actions (repository staff only: login required)