title: Evolutionary history of Ichthyosaura alpestris (Caudata, Salamandridae) inferred from the combined analysis of nuclear and mitochondrial markers.
abstract: Widespread species with morphologically and ecologically differentiated populations are key to understand speciation because they allow investigating the different stages of the continuous process of population divergence. The alpine newt, Ichthyosaura alpestris, with a range that covers a large part of Central Europe as well as isolated regions in all three European Mediterranean peninsulas, and with strong ecological and life-history differences among populations, is an excellent system for such studies. We sampled individuals across most of the range of the species, and analyzed mitochondrial (1442 bp) and nuclear (two nuclear genes -1554 bp- and 35 allozyme loci) markers to produce a time-calibrated phylogeny and reconstruct the historical biogeography of the species. Phylogenetic analyses of mtDNA data produced a fully resolved topology, with an endemic, Balkan clade (Vlasina) which is sister to a clade comprising an eastern and a western group. Within the former, one clade (subspecies I. a. veluchiensis) is sister to a clade containing subspecies I. a. montenegrina and I. a. serdara as well as samples from southern Romania, Bosnia-Herzegovina, Serbia and Bulgaria (subspecies I. a. reiseri and part of I. a. alpestris). Within the western group, populations from the Italian peninsula (subspecies I. a. apuana and I. a. inexpectata) are sister to a clade containing samples from the Iberian Peninsula (subspecies I. a. cyreni) and the remainder of the samples from subspecies I. a. alpestris (populations from Hungary, Austria, Poland, France, Germany and the larger part of Romania). Results of (∗)BEAST analyses on a combined mtDNA and nDNA dataset consistently recovered with high statistical support four lineages with unresolved inter-relationships: (1) subspecies I. a. veluchiensis; (2) subspecies I. a. apuana+I. a. inexpectata; (3) subspecies I. a. cyreni+part of subspecies I. a. alpestris (the westernmost populations, plus most Romanian populations); and (4) the remaining populations, including subspecies I. a. serdara, I. a. reiseri and I. a. montenegrina and part of subspecies I. a. alpestris, plus samples from Vlasina. Our time estimates are consistent with ages based on the fossil record and suggest a widespread distribution for the I. alpestris ancestor, with the split of the major eastern and western lineages during the Miocene, in the Tortonian. Our study provides a solid, comprehensive background on the evolutionary history of the species based on the most complete combined (mtDNA+nDNA+allozymes) dataset to date. The combination of the historical perspective provided by coalescent-based analyses of mitochondrial and nuclear DNA variation with individual-based multilocus assignment methods based on multiple nuclear markers (allozymes) also allowed identification of instances of discordance across markers that highlight the complexity and dynamism of past and ongoing evolutionary processes in the species.
authors.affiliation: Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ap. Postal 70-275, Ciudad Universitaria, México DF 04510, Mexico; Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales MNCN-CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Recuero
authors.affiliation: Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales MNCN-CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain; Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge CB2 3DY, UK.
authors.forename: David
authors.initials: D
authors.lastname: Buckley
authors.affiliation: Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales MNCN-CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: García-París
authors.affiliation: Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands.
authors.forename: Jan W
authors.initials: JW
authors.lastname: Arntzen
authors.affiliation: University Ovidius Constanţa, Faculty of Natural Sciences and Agricultural Sciences, Al. Universităţii 1, corp B, Constanţa 900470, Romania.
authors.forename: Dan
authors.initials: D
authors.lastname: Cogălniceanu
authors.affiliation: Instituto de Investigación en Recursos Cinegéticos, Ronda de Toledo, s/n, 13005 Ciudad Real, Spain. Electronic address: inigomsolano@gmail.com.
authors.forename: Iñigo
authors.initials: I
authors.lastname: Martínez-Solano
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D005060:Europe; D005260:Female; D006239:Haplotypes; D008957:Models, Genetic; D010802:Phylogeny; D012455:Salamandridae / Q000145:classification* / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial
keywords: Allozymes; Amphibia; Phylogeography; Systematics; mtDNA; nDNA