Population genetic structure in the Iberian cyprinid fish Iberochondrostoma lemmingii (Steindachner, 1866): disentangling species fragmentation and colonization processes

Abstract

Interplay between the complex geography, hydrogeomorphological history, past climatic changes, and anthropogenic pressures is likely responsible for the current diversity and species' distribution of freshwater fishes in the Iberian Peninsula. To further disentangle the evolutionary processes promoting the diversification of endemic Iberian Cyprinids through time and space, we explored the patterns of genetic diversity of the Iberian archedmouth nase, Iberochondrostoma lemmingii (Steindachner, 1866), using molecular markers rendering at different timescales: the mitochondrial gene cytochrome b and seven microsatellite loci. Both markers showed significant differentiation of populations though the relative genetic distances among populations were different between markers. Mitochondrial DNA results indicate the isolation of hydrographic basins as the main driver of population differentiation, with Tejo as the centre of diversification. The results also support connections between Tejo, Guadiana, and Guadalquivir, with levels of divergence suggesting an earlier severance of Guadalquivir, whereas Guadiana and Tejo maintained connections until a more recent past. Establishment of more peripherial populations in small southern basins (Quarteira and Almargem) could have been ruled by founder events. However, the analysis of present-day genetic configuration suggested by microsatellite data implies, for the first time, the involvement of other factors in the evolution of arched-mouth Iberian nase populations. Relative low genetic distances between inter-basin populations (Tejo and Guadiana) and the lack of concordance between differentiation and geography suggest a possible influence of human-mediated translocations in the population genetic patterns of I. lemmingii. High intra-basin differentiation levels were found within Tejo and Guadiana and may be associated with factors intrinsic to the species (e.g. low dispersal capability) or natural and/or artificial barriers to gene flow. The low vagility of the species appears to be an important factor influencing the evolutionary processes shaping the phylogeographical patterns of I. lemmingii, which could be relevant for the conservation of this threatened species.

Evolutionary history and population genetics of a cyprinid fish (Iberochondrostoma olisiponensis) endangered by introgression from a more abundant relative

“…Compared to other endangered freshwater fishes from Iberia or elsewhere, I. olisiponensis shows extremely low levels of genetic polymorphism and high population subdivision (e.g. Alves et al 2001a;Salgueiro et al 2003;Mesquita et al 2005;Sousa et al 2010;Dowling et al 2012;Lopes-Cunha et al 2012;Osborne et al 2012;Sterling et al 2012;Chen et al 2013). Furthermore, in addition to the suspected old hybridization events discussed above, we present clear evidence that I. olisiponensis is currently being subjected to strong genetic assimilation through hybridization with the sympatric I. lusitanicum (Gante et al 2010 and present study).…”

Phylogeography, historical demography and habitat suitability modelling of freshwater fishes inhabiting seasonally fluctuating Mediterranean river systems: a case study using the Iberian cyprinid Squalius valentinus

“…This genetic structure among basins, which has also been described for other Iberian freshwater fish species (Doadrio & Carmona ; Almada & Sousa‐Santos ; Lopes‐Cunha et al . ), can be linked to historical palaeogeographical factors related to the Plio‐Pleistocene formation of the current exorheic Iberian basins (Calvo et al . ) and to a lesser extent to the Mediterranean climate.…”

Paleobiogeography of an Iberian endemic species,Luciobarbus sclateri(Günther, 1868) (Actinopterygii, Cyprinidae), inferred from mitochondrial and nuclear markers

“…This study has shown the imprint of paleohydrological processes in the population structure of L. sclateri , characterized by a complex history leading to present‐day diverse watershed interconnections in southern Spain that have masked past relationships, in contrast with the clear patterns of population structure found in other freshwater fish populations inhabiting other areas of the Iberian Peninsula during the Plio‐Pleistocene (Doadrio & Carmona, ; Lopes‐Cunha et al., ; Robalo, Almada, Levy, & Doadrio, ). This study has also shown that the lack of a complete sampling could highly affect the explanation of the evolutionary processes that have modeled the population structure and the phylogeographic models of L. sclateri .…”