Morphological diversity and phylogenetic relationships within a South-American clade of iguanian lizards (Liolaemidae: Phymaturus)

Abstract

With 36 species and at least nine potentially independent lineages (not formally described yet) occurring mostly in theAndes and adjacent Patagonia and Puna plateau areas, Phymaturus lizards represent one of the most endemic vertebrategroups of the arid southwestern region of South America. Phylogenetic relationships among species of Phymaturus areinferred using mainly a morphological data set of 206 characters. Also available sequences of mitochondrial DNA for sev-en terminals were added for a total evidence analysis. Most information is included in the discrete characters block; mostcharacters involve color pattern, osteology and squamation. Continuous characters were taken from body proportions,squamation and skeletons. Among morphological data, binary polymorphic characters were analyzed applying the scaledcoding criteria. Continuous characters were entered in the analysis using standardized ranges, a method that allows a sim-ple optimization to estimate distances/costs avoiding the arbitrary coding as discrete characters. For our parsimony anal-yses we chose the implied weights method, which underweights homoplastic characters. Several runs were madeanalyzing all the information combined and also separating morphological from molecular datasets. Binary polymor-phisms were also analyzed as missing data. All characters affected by sexual dimorphism were analyzed separating thesexes; female information was more congruent with the total evidence analysis. Characters involving continuous and poly-morphic information are relevant for searching and building phylogenetic hypotheses in Phymaturus. There exists signif-icant congruence between the molecular information analyzed in this study and previous published analyses. Within bothmain clades of Phymaturus, northern subgroups are those more recently originated during the genus diversification. Spe-cies belonging to the puna subclade of the palluma group are arranged in two natural groups, one distributed in the north(Catamarca and La Rioja provinces), and the other in the south, La Rioja and San Juan provinces. Within the patagonicusgroup, the majority of the species are arranged in a south-central Chubut clade, eastern-central Chubut clade, central Rio Negro clade and a Payunia clade.

On the evolution and diversification of an Andean clade of reptiles: combining morphology and DNA sequences of thepallumagroup (Liolaemidae:Phymaturus)

“…The main nodes found by Lobo et al . (2012a) were confirmed by a recent DNA analysis (Morando et al ., ). In Figure we show congruent nodes recovered in both independent studies.…”

“…Note that even when only half of the terminal taxa are shared between Lobo et al . (2012a) and Morando et al . (), and different optimality criteria for building the trees were used (parsimony and Bayesian analysis), around half of the nodes remain the same.…”

“…Corbalán, Scolaro & Debandi () found a population in Laguna Diamante (Mendoza) that was considered different from the other populations known in this region ( P. verdugo , P. palluma , and P. roigorum ), and described Phymaturus gynechlomus Corbalán, Scolaro & Debandi, . In Lobo, Abdala & Valdecantos (2012a), and more recently in Lobo & Etheridge (), P. gynechlomus is considered a synonym of P. palluma , contrary to the assertion made by Scolaro (). Lobo, Abdala & Valdecantos () described four new species from Argentina, including two assigned to the palluma group: Phymaturus querque Lobo et al ., and Phymaturus laurenti Lobo et al ., .…”

“…An updated list of recognized species (22) of the palluma group is shown in Table . About the phylogeny and relationships of the palluma group, the first approach was made by Lobo & Quinteros (); at that time a data set of 133 characters and 22 terminal taxa was analysed, finding several results that were confirmed in later investigations (Lobo et al ., 2012a; Morando et al ., ): (1) the palluma species group was recovered as monophyletic, supported by several apomorphies; (2) P. dorsimaculatus , the population reported from Chillán (Chile) and P. querque were found as basal to the group; and (3) the monophyly of a clade endemic from the Puna region of Argentina was recovered. Seven years later, a new morphological analysis was performed by Lobo et al .…”

“…Seven years later, a new morphological analysis was performed by Lobo et al . (2012a). This new analysis included 206 characters and 36 terminal taxa, and gave confirmation to those previous results.…”