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

High reproductive effort in a vulnerable lizard from high altitudes in Argentina: Reproductive biology and sexual dimorphism in Phymaturus extrilidus

Reproductive biology is fundamental to understanding the ecology and evolution of lizards which, in turn, is essential for the definition of the species´ conservation status. We studied life-history traits related to the reproduction of the Phymaturus extrilidus lizard, including the male and female reproductive cycles, litter size, mean annual reproductive output, reproductive effort, sexual maturity size and sexual dimorphism, body condition, and fat body cycles. We found sexual dimorphism in size and shape, supporting the hypotheses of sexual and fecundity selection. Females exhibited biennial reproductive cycles synchronous with the annual prenuptial male cycle, adjusted for the maturation of the vitellogenic follicles of females. Females of P. extrilidus have the highest mean annual reproductive output (MARO=1.14) recorded in Phymaturus, and this is accompanied by the highest reproductive effort (C=0.28, C energetic =0.31). Births occur from late summer to early autumn. The female reproductive cycle, strictly biennial, like all species of the P. palluma group, and the vitellogenesis in particular, appear to be limited by body condition and the amount of fat body stored. This study presents the fundamental reproductive traits of P. extrilidus that can provide valuable information to be used in the evaluation of the conservation status of this species.

Looking at the past to infer into the future: Thermal traits track environmental change in Liolaemidae

The diversity of habitats generated by the Andes uplift resulted a mosaic of heterogeneous environments in South America for species to evolve a variety of ecological and physiological specializations. Species in the lizard family Liolaemidae occupy a myriad of habitats in the Andes. Here, we analyze the tempo and mode of evolution in the thermal biology of liolaemids. We assessed whether there is evidence of local adaptation (lability) or conservatism (stasis) in thermal traits. We tested the hypothesis that abiotic factors (e.g., geography, climate) rather than intrinsic factors (egg-laying [oviparous] or live-bearing [viviparous], substrate affinity) explain variation in field active body temperature (T_b ), preferred temperature (T_p ), hours of restriction of activity, and potential hours of activity. Although most traits exhibited high phylogenetic signal, we found variation in thermal biology was shaped by geography, climate, and ecological diversity. Ancestral character reconstruction showed shifts in T_b tracked environmental change in the past ∼20,000 years. Thermal preference is 3°C higher than T_b , yet exhibited a lower rate of evolution than T_b and air temperature. Viviparous Liolaemus have lower T_b s than oviparous species, whereas T_p is high for both modes of reproduction, a key difference that results in a thermal buffer for viviparous species to cope with global warming. The rapid increase in environmental temperatures expected in the next 50-80 years in combination with anthropogenic loss of habitats are projected to cause extirpations and extinctions in oviparous species.

Connection, isolation and reconnection: Quaternary climatic oscillations and the Andes shaped the phylogeographical patterns of the Patagonian bee Centris cineraria (Apidae)

The joint effect of the Andes as a geographical barrier and the Quaternary glaciations as promoters of genetic divergence remains virtually unexplored in southern South America. To help fill this knowledge gap, in this study we investigated the demographic history of Centris cineraria, a solitary bee mainly distributed in Patagonia. We used mitochondrial and nuclear markers and performed phylogeographical and dating analyses, adjusted spatio-temporal diffusion and species distribution models, and used Approximate Bayesian Computation to identify likely historical demographic scenarios. Our results revealed that during glacial periods the Andes represented a barrier due to the extent of the ice-sheets and the occurrence of unsuitable habitats, while interglacials allowed for gene flow across the Andes. Secondary contact between previously isolated lineages was evident across at least two low-altitude Andean areas, the northern one being a putative glacial refugium. Our findings also suggest that C. cineraria has persisted in situ in four periglacial refugia located along a north–south transect, congruent with the maximum extent of the ice sheet during the Greatest Patagonian Glaciation. As the first phylogeographical study of Patagonian insects, our work reveals that the interaction between Quaternary climatic oscillations and the Andes as a barrier was the main driver of the spatial and demographic history of C. cineraria.

Macroevolution of sexual size dimorphism and reproduction-related phenotypic traits in lizards of the Chaco Domain

BACKGROUND

Comparing sexual size dimorphism (SSD) in the light of the phylogenetic hypothesis may help to understand the phenotypic evolution associated with sexual selection (size of whole body and of reproduction-related body parts). Within a macroevolutionary framework, we evaluated the association between the evolution of SSD and the evolution of reproduction-related phenotypic traits, and whether this association has favored female fecundity, considering also variations according to reproductive modes. We focused on the lizard species that inhabit the Chaco Domain since this is a natural unit with a high diversity of species.

RESULTS

The residual SSD was related positively with the residuals of the reproduction-related phenotypic traits that estimate intrasexual selection and with the residuals of inter-limb length and, according to fecundity selection, those residuals were related positively with the residuals of clutch size in oviparous species. Lizards of the Chaco Domain present a high diversity of SSD patterns, probably related to the evolution of reproductive strategies.

CONCLUSIONS

Our findings highlight that the sexual selection may have acted on the whole-body size as well as on the size of body parts related to reproduction. Male and female phenotypes evolutionarily respond to variations in SSD, and an understanding of these patterns is essential for elucidating the processes shaping sexual phenotype diversity from a macroevolutionary perspective.

But they move! Vicariance and dispersal in southern South America: Using two methods to reconstruct the biogeography of a clade of lizards endemic to South America

This study aims to identify events that modeled the historical biogeography of Phymaturus, using three methodologies: Spatial Analysis of Vicariance (VIP), Statistical Dispersal-Vicariance Analysis (S-DIVA), and Bayesian Binary Method MCMC (BBM). In order to assign areas for the Dispersal-Vicariance and the BBM analyses, we preferred not to use predefined areas, but to identify areas defined via an endemism analysis of Phymaturus species. The analyses were conducted using the same basic topology, which we obtained by constructing a metatree with two recent phylogenies, both morphology and molecular-based. This topology was also used to obtain time divergence estimates in BEAST, using more outgroups than for the metatree in order to get more accurate estimates. The S-DIVA analysis based on the metatree found 25 vicariance events, 20 dispersals and two extinctions; the S-DIVA analysis based on the BEAST tree yielded 30 vicariance events, 42 dispersal events and five extinctions, and the BBM analysis yielded 63 dispersal events, 28 vicariance events and 1 extinction event. According to the metatree analysis, the ancestral area for Phymaturus covers northern Payunia and southern Central Monte. A vicariant event fragmented the ancestral distribution of the genus, resulting in northern Payunia and southern Central Monte as ancestral area for the P. palluma group, and southern Payunia for the P. patagonicus group. The analysis based on the BEAST tree showed a more complex reconstruction, with several dispersal and extinction events in the ancestral node. The Spatial Analysis of Vicariance identified 41 disjunct sister nodes and removed 10 nodes. The barrier that separates the P. palluma group from the P. patagonicus group is roughly congruent with the southern limit of the P. palluma group. The ancestral range for the genus occupies a central position relative to the distribution of the group, which implies that the species must have migrated to the north (P. palluma group) and to the south (P. patagonicus group). To answer questions related to the specific timing of the events, a molecular clock for Phymaturus was obtained, using a Liolaemus fossil for calibration. The present contribution provides a hypothetical framework for the events that modeled the distribution of Phymaturus.

Structure, variation, and systematic implications of the hemipenes of liolaemid lizards (Reptilia: Liolaemidae)

The structure of copulatory organs is widely used in systematics for both differentiating species and for studying phylogenetic relationships. We describe the hemipenes of 42 species belonging to the genus Liolaemus, representing most of their internal groups. We reported 42 characters, the majority not published previously. We constructed a metatree based on previously proposed phylogenetic studies and optimized the hemipenial characters in this topology. Among the most informative characters are presence or absence of flounces or calyces on the sulcate face, ornamentation of the apex, presence or absence of an asulcate face prominence, and presence of a thickening on the proximal region of the asulcate face. Furthermore, we performed a phylogenetic analysis exclusively with the hemipenial characters, not with the intention of making a phylogeny based on this single set of characters, but rather to demonstrate their significance for the reconstruction of relationships in Liolaemus. The obtained results show that the main clades are recovered. We also compared the hemipenial morphology between closely related species to evaluate its taxonomic importance. We conclude that in Liolaemus, the hemipenes can be used both for the differentiation of species and to provide additional evidence for establishing their phylogenetic relationships.

Evolution of the cloacal and genital musculature, and the genitalia morphology in liolemid lizards (Iguania: Liolaemidae) with remarks on their phylogenetic bearing

In this study, we describe the intra- and interspecific anatomical variations of cloacal and related muscles of male and female genitalia in species of five iguanian genera (three liolemid:Ctenoblepharys,Liolaemus, andPhymaturusplusDiplolaemusleopardinusandTropidurusmelanopleurusas outgroups). We found variations (seventeen characters) in topology, origin and insertion areas, tendon morphology and size of the musculature of this region. We also describe the variations of hemipeneal morphology, which is especially notable for the hemipenis ofC. adspersa,D. leopardinus, andT. melanopleurus, as this is first time they are described in the literature. Among the most significant findings are the identification of three new muscles, two of them inserted on the roof of the cloacal chamber (anterior and posterior cloacal retractor) and the third inserted superficially in the floor of the cloaca, just before anterior to the precloacal glands row (superficialis cloacalis retractor). We report sexual dimorphism in seven muscle characters. Musculature related to hemiclitoris is reduced in proportion to its size in comparison to the degree of development of male genitalia and associated musculature. The evolution of characters was traced on the known phylogenetic hypotheses of relationships among families. Characters taken from the cloacal/genital myology bring similar support to the liolaemid tree even rooting the analysis using different outgroups. In addition, a phylogenetic study using only myological characters was performed. In this case,C. adspersawas found to be more related toLiolaemusspecies instead of being basal toLiolaemusplusPhymaturus.