Phylogeography and historical demography of the Lusitanian snail Elona quimperiana reveal survival in unexpected separate glacial refugia

Abstract

BackgroundPresent day distributions of Palearctic taxa in northern latitudes mainly result from populations having survived in local patches during the Late Pleistocene and/or from recolonizing populations from southern temperate refugia. If well-studied Mediterranean and eastern European refugia are widely accepted, some recent biogeographical assumptions still remain unclear, such as the occurrence of multiple glacial refugia in Iberia and cryptic refugia in northern Europe during the last glaciations. The Lusitanian snail Elona quimperiana has a remarkably disjunct distribution, limited to northwestern France (Brittany), northwestern Spain and the Basque Country. By describing the phylogeographical structure of this species across its entire range, the present study attempts to identify refugia and subsequent recolonization routes.ResultsResults based on 16S and COI gene sequences showed that the low genetic diversity observed in the Brittany populations should be associated with a recent demographic expansion. By contrast, populations from Spain exhibit several differentiated lineages and are characterized by demographic equilibrium, while the Basque populations are the only ones harboring typical distinct haplotypes. The center of the star-like networks of both gene sequences is occupied by a common ancestral-like haplotype found in Brittany and Spain, which might have originated from the middle of Northern Spain (i.e. Asturias, eastern Lugo and western Cantabria). Estimates of the divergence time between the Spain-Brittany and Basque lineages strongly suggest that E. quimperiana survived the Pleistocene glaciations in distinct refugia on the Iberian Peninsula, one of which is situated in Picos de Europa, and the other in the Basque Country. The occurrence of a northern refugium in France cannot be rejected as of yet.ConclusionPresent results confirm the Iberian origin of the land snail E. quimperiana and strongly support the emerging phylogeographic hypothesis of multiple refugia in Iberia during the last glaciations. The scenario of a spatial expansion of E. quimperiana from an Iberian refuge located in Asturias to northern areas provides the most probable explanation for the present distribution of this land snail. By harboring distinct haplotypes, the Basque Country populations appear to be of great importance in terms of potential adaptation, long term persistence and hence, the conservation of E. quimperiana.

New evidence of sea‐level lowstands and paleoenvironment during MIS 6 and 4 in the Cantabrian coastal karst: the Cobiheru cave (North Iberia)

“…Thus, this species lived on the Cantabrian Coast since the late Middle Pleistocene and during the Upper Pleistocene, as suggested by the Upper Palaeolithic site of El Cuco rock-shelter in Cantabria (Gutiérrez-Zugasti et al, 2013). This finding supports the hypothesis that the Cantabrian Coast was a refugium for Elona quimperiana during the Last Glacial Cycle (Vialatte et al, 2008). This species also provides information on palaeoenvironmental conditions since this snail lives in a wet template climate, its diet being related to the fallen leaves of the deciduous forest with shade areas, frequently dominated by Quercus taxa (Ramos, 1998;Vialatte et al, 2008).…”

“…This finding supports the hypothesis that the Cantabrian Coast was a refugium for Elona quimperiana during the Last Glacial Cycle (Vialatte et al, 2008). This species also provides information on palaeoenvironmental conditions since this snail lives in a wet template climate, its diet being related to the fallen leaves of the deciduous forest with shade areas, frequently dominated by Quercus taxa (Ramos, 1998;Vialatte et al, 2008). Consequently, Elona quimperiana suggests the development of wet deciduous forest prior to 350 ka.…”

Phylogeography of Southern Water Vole (Arvicola sapidus): evidence for refugia within the Iberian glacial refugium?

“…In particular, A. sapidus patterns add evidence for the consideration of the North quadrant of Iberia as a subrefugium, as the spatial distribution of partition III overlaps with that described for divergent lineages in other species [e.g. vertebrates (Paulo et al 2008) and invertebrates (Vila et al 2005;Vialatte et al 2008)]. The Eastern Pyrenees (partition VII) have also been shown to harbour divergent population in other species (Vialatte et al 2008).…”

“…2008)]. The Eastern Pyrenees (partition VII) have also been shown to harbour divergent population in other species (Vialatte et al. 2008).…”

“…vertebrates (Paulo et al 2008) and invertebrates (Vila et al 2005;Vialatte et al 2008)]. The Eastern Pyrenees (partition VII) have also been shown to harbour divergent population in other species (Vialatte et al 2008). Interestingly, two Iberian refugia have also been proposed for Microtus agrestis, one in central Portugal and one in northern Spain (Jaarola & Searle 2004).…”