INVESTIGADORES
AVILA luciano Javier
congresos y reuniones científicas
Título:
Paraphyletic patterns in Eulaemus clade (Squamata:Liolaemus): evidence for new lineages and different demographic and historical processes based on a multilocus approach
Autor/es:
OLAVE, M.; AVILA, L.J.; SITES, J.W., JR.; MORANDO, M.
Lugar:
Curitiba
Reunión:
Congreso; IX Congreso Latinoamericano de Herpetologia; 2011
Institución organizadora:
Sociedade Brasileira de Herpetologia
Resumen:
The lizard genus Liolaemus is endemic to temperate South America and includes 225 recognized species. Since Laurent (1983) presented a morphologic study, the Liolaemus genus was divided in two subgenus: chiliensis and Eulaemus (Argentinean) groups, distributed mainly to the west (Chile) and east (Argentina) of the Andes, respectively. The genus distribution extends to Uruguay and Brazil on the east coast, and to Paraguay, Bolivia and Peru on the north. Morphological and mitochondrial characters have been used to propose phylogenetic hypotheses for different clades within this genus, most of them with incomplete taxon sampling and very low intraspecific sampling. On the other side, phylogeographic studies have revealed incongruences with traditional species taxonomy, different species complexes have been proposed, and it is clear that species limits are not well defined in most cases. Based on morphological and molecular evidence, several species previously considered unique species with a wide distribution range and high chromatic and morphologic variation, have been described as new taxa. This situation reveals the poor taxonomic knowledge of Liolaemus, which is commonly the principal cause for paraphyletic patterns in extensive phylogenetic studies. Also, incomplete lineage sorting and introgression are hypotheses that should be contrasted as plausible explanations for these patterns. To contrast those hypotheses, it is important to considerer that the mitochondrial genome is particularly useful to detect introgression, because a lack of recombination insures that all base positions introgress as a completely linked block. Thus, a mtDNA introgressed fragment will reflect the heterospecific origin of it’s mitochondrial genome; and recognizing this introgression requires evaluating a mitochondrial gene tree against a nuclear background that identifies the participating taxa. Thus, in order to detect and differentiate these patterns, intensive sampling (taxa, distribution range, and markers) is needed. In this work we present the first well-supported molecular phylogenetic hypothesis for Eulaemus taxa based on multiple nuclear molecular markers (protein coding loci, anonymous loci, intron locus) as well as mitochondrial markers (cytb-12S). The Eulaemus clade includes 73 described species, and we included multiple representatives of all large groups within the subgenus. We also included intensive intraspecific sampling for described species within the boulengeri and rothi complexes. Based on Bayesian analyses, we detect evidence of incomplete lineage sorting, hybridization and new candidate species.