Phylogeography of Sodreaninae harvestmen (Arachnida: Opiliones: Gonyleptidae): Insights into the biogeography of the southern Brazilian Atlantic Forest

Phylogenetic relationships of the genus Mischonyx Bertkau, 1880, with taxonomic changes and three new species description (Opiliones: Gonyleptidae)

The type species of Mischonyx Bertkau 1880, Mischonyx squalidus, was described based on a juvenile. The holotype is lost. Based on a revision of publications, the genus includes 12 species, all in Brazil. The objectives of this research are: to propose a phylogenetic hypothesis for Mischonyx based on Total Evidence (TE); propose taxonomic changes based on the phylogeny; and analyze the phylogenetic hypothesis biogeographically. Using the exemplar approach to taxon selection, we studied 54 specimens, 15 outgroups and 39 ingroup taxa using seven molecular markers (28S, 12S and 16S ribosomal genes, citochrome oxidase subunit I gene, carbamoyl-phosphate synthetase gene, internal transcribed spacer subunit 2 and histone H3 gene), totaling 3,742 bp, and 128 morphological characters. We analyzed the dataset under three optimality criteria: Maximum likelihood (ML), Maximum parsimony (MP) and Bayesian. We discuss the transformation of character states throughout the phylogeny, the different phylogenetic hypotheses using different datasets and the congruence of evidence between the clades obtained by the phylogenetic analysis and the biogeographical hypothesis for the Atlantic Forest areas of endemism. We estimate that Mischonyx clade diverged 50.53 Mya, and inside the genus there are two major clades. One of them cointains species from Paraná, Santa Catarina, South of São Paulo and Serra do Mar Areas of Endemism and the other has species from Espinhaço, Bocaina, South coast of Rio de Janeiro and Serra dos Órgãos Areas of Endemism. The first split inside these two clades occurred at 48.94 and 44.80 Mya, respectively. We describe three new species from Brazil: Mischonyx minimus sp. nov. (type locality: Petrópolis, Rio de Janeiro), Mischonyx intervalensis sp. nov. (type locality: Ribeirão Grande, São Paulo) and Mischonyx tinguaensis sp. nov (type locality: Nova Iguaçu, Rio de Janeiro). The genus Urodiabunus Mello-Leitão, 1935 is considered a junior synonym of Mischonyx. Weyhia spinifrons Mello-Leitão, 1923; Weyhia clavifemur Mello-Leitão, 1927 and Geraeocormobius reitzi Vasconcelos, 2005 were transferred to Mischonyx. Mischonyx cuspidatus (Roewer, 1913) is a junior synonym of M. squalidus Bertkau, 1880. In the results of the phylogenetic analyses, Gonyleptes antiquus Mello-Leitão, 1934 (former Mischonyx antiquus) does not belong in Mischonyx and its original combination is re-established. As it is now defined, Mischonyx comprises 17 species, with seven new combinations.

Rugged relief and climate promote isolation and divergence between two neotropical cold-associated birds

The role of historical factors in establishing patterns of diversity in tropical mountains is of interest to understand the buildup of megadiverse biotas. In these regions, the historical processes of range fragmentation and contraction followed by dispersal are thought to be mediated by the interplay between rugged relief (complex topography) and climate fluctuations and likely explain most of the dynamics of diversification in plants and animals. Although empirical studies addressing the interaction between climate and topography have provided invaluable insights into population divergence and speciation patterns in tropical montane organisms, a more detailed and robust test of such processes in an explicit spatio-temporal framework is still lacking. Consequently, our ability to gain insights into historical range shifts over time and the genomic footprint left by them is limited. Here, we used niche modeling and subgenomic population-level datasets to explore the evolution of two species of warbling finches (genus Microspingus) disjunctly distributed across the Montane Atlantic Forest, a Neotropical region with complex geological and environmental histories. Population structure inferences suggest a scenario of three genetically differentiated populations, which are congruent with both geography and phenotypic variation. Demographic simulations support asynchronous isolation of these populations as recently as ∼40,000 years ago, relatively stable population sizes over recent time, and past gene flow subsequent to divergence. Throughout the last 800,000 years, niche models predicted extensive expansion into lowland areas with increasing overlap of species distributions during glacial periods, with prominent retractions and isolation into higher altitudes during interglacials, which are in line with signs of introgression of currently isolated populations. These results support a dual role of cyclical climatic changes: population divergence and persistence in mountain tops during warm periods followed by periods of expansion and admixture in lower elevations during cold periods. Our results underscore the role of the interplay between landscape and climate as an important mechanism in the evolution of the Neotropical montane biota.

A fresh look at Cosmetus Perty, 1833 (Opiliones: Cosmetidae), with new synonymies and description of two new species from Colombia

Cosmetus Perty, 1833 is the type genus of the most diverse subfamily of Laniatores, Cosmetinae. The genus currently includes 22 valid species with a disconnected distribution, including coastal forests of NE Brazil, dry forests of the Ecuadorian Pacific, Choc-Darien moist forests and the Venezuelan Andes. The morphology among species in the genus is quite variable, but they share almost exclusively the fused spine in area III. The type species Cosmetus varius is little known due to few, poor quality illustrations, a vague type locality, and lost type material, and was misidentified by Koch in 1840, making it difficult to define or even taxonomically revise the genus. Herein we: (1) provide distribution maps for nominal Cosmetus species; (2) recognize the poorly defined type species C. varius as a species occurring in central-eastern Bahia, agreeing with the itinerary of Spix and von Martius; (3) synonymize three other species from central-eastern Bahia with C. varius; (4) provide images of the external morphology of three Brazilian species of the genus; and (5) describe two new sympatric species from the Colombian Pacific region (Choc-Darien moist forest), thus representing the first report of the genus for the country. Both Colombian species, Cosmetus acanti sp. nov. and Cosmetus villarreali sp. nov., have similar external morphology but are remarkably different in genital morphology. Morphological evidence indicates that Cosmetus may be an artificial group. However, given the chaotic taxonomy of the family Cosmetidae, and the deep intertwining of nomenclature, we do not know at the moment where each of those species should be classified.

Systematics and phylogeography of the Brazilian Atlantic Forest endemic harvestmen Neosadocus Mello-Leitão, 1926 (Arachnida: Opiliones: Gonyleptidae)

Neosadocus harvestmen are endemic to the Southern Brazilian Atlantic Forest. Although they are conspicuous and display great morphological variation, their evolutionary history and the biogeographical events underlying their diversification and distribution are still unknown. This contribution about Neosadocus includes the following: a taxonomic revision; a molecular phylogenetic analysis using mitochondrial and nuclear markers; an investigation of the genetic structure and species' diversity in a phylogeographical framework. Our results show that Neosadocus is a monophyletic group and comprises four species: N. bufo, N. maximus, N. robustus and N. misandrus (which we did not find on fieldwork and only studied the female holotype). There is astonishing male polymorphism in N. robustus, mostly related to reproductive strategies. The following synonymies have resulted from this work: "Bunoweyhia" variabilis Mello-Leitão, 1935 = Neosadocus bufo (Mello-Leitão, 1926); and "Bunoweyhia" minor Mello-Leitão, 1935 = Neosadocus maximus (Giltay, 1928). Most divergences occurred during the Miocene, a geological epoch marked by intense orogenic and climatic events in the Brazilian Atlantic Forest. Intraspecific analyses indicate strong population structure, a pattern congruent with the general behavior and physiological constraints of Neotropical harvestmen.

North-south and climate-landscape-associated pattern of population structure for the Atlantic Forest White Morpho butterflies

Atlantic Forest White Morpho butterflies, currently classified as Morpho epistrophus and M. iphitus, are endemic to the Atlantic Forest, where they are widely distributed throughout heterogeneous environmental conditions. Studies with endemic butterflies allow to elucidate questions on both patterns of diversity distribution and current and past processes acting on insect groups in this biodiversity hotspot. In the present study, we characterized one mtDNA marker (COI sequences) and developed 11 polymorphic loci of microsatellite for 22 sampling locations distributed throughout the entire Atlantic Forest domain. We investigated both the taxonomic limits of taxa classified as White Morpho and the structure and distribution of the genetic diversity throughout their populations. Genetic markers and distribution data failed to identify species diversification, population structure, or isolation among subpopulations attributed to different taxa proposed for the White Morpho, suggesting that the current distinction between two species is unreasonable. The Bayesian coalescent tree based on COI sequences also failed to recover monophyletic clades for the putative species, and pointed instead to a north-south oriented pattern of genetic structure, with the northern clade coalescing later than the southern clade. Northern samples also showed more intragroup structure than southern samples based on mtDNA data. Clustering tests based on microsatellites indicated the existence of three genetic clusters, with turnover between the states of Paraná and São Paulo. The north-south pattern found for the White Morpho populations is showed for the first time to a endemic AF insect and coincides with the two different bioclimatic domains previously described for vertebrates and plants. Population structure observed for these butterflies is related to climate- and landscape-associated variables, mainly precipitation and elevation.

Comparative phylogeography and palaeomodelling reveal idiosyncratic responses to climate changes in Neotropical paper wasps

The impact of the broad disjunction between Amazonia and the Atlantic Forest on biodiversity has been the theme of several discussions in recent decades. Here, we evaluate the effects of dependence on humid environments and the role of historical factors on the level, distribution and structuring of genetic variation in widely distributed Neotropical insects. For such, we test whether climatically stable zones (i.e. refuges) in both Amazonia and the Atlantic Forest concentrate higher genetic diversity in the social paper wasps Angiopolybia pallens and Synoeca surinama. We found that historical events have avoided the interchange of A. pallens between both rainforests at least since the Early Pliocene and that ancient colonization in north-western Amazonia and the Bahia refuge significantly predicts genetic diversity in populations of this species. Conversely, the split between the Atlantic Forest and remaining western populations of S. surinama is more recent (Plio-Pleistocene); this species has considerably lower genetic diversity than A. pallens and such diversity is mostly concentrated in Amazonia and in the cerrado biome (savanna) than in the Atlantic Forest. Finally, we propose that the occurrence of species that exhibit such distribution patterns should be taken into consideration when establishing areas for conservation.

From micro- to macroevolution: insights from a Neotropical bromeliad with high population genetic structure adapted to rock outcrops

Geographic isolation and reduced population sizes can lead to local extinction, low efficacy of selection and decreased speciation. However, population differentiation is an essential step of biological diversification. In allopatric speciation, geographically isolated populations differentiate and persist until the evolution of reproductive isolation and ecological divergence completes the speciation process. Pitcairnia flammea allows us to study the evolutionary consequences of habitat fragmentation on naturally disjoint rock-outcrop species from the Brazilian Atlantic Rainforest (BAF). Our main results showed low-to-moderate genetic diversity within populations, and deep population structuring caused by limited gene flow, low connectivity, genetic drift and inbreeding of long-term isolation and persistence of rock-outcrop populations throughout Quaternary climatic oscillations. Bayesian phylogenetic and model-based clustering analyses found no clear northern and southern phylogeographic structure commonly reported for many BAF organisms. Although we found two main lineages diverging by ~2 Mya during the early Pleistocene, species' delimitation analysis assigned most of the populations as independent evolving entities, suggesting an important role of disjoint rock outcrops in promoting high endemism in this rich biome. Lastly, we detected limited gene flow in sympatric populations although some hybridization and introgression were observed, suggesting a continuous speciation process in this species complex. Our data not only inform us about the extensive differentiation and limited gene flow found among Pitcairnia flammea species complex, but they also contain information about the mechanisms that shape the genetic architecture of small and fragmented populations of isolated rock outcrop of recently radiated plants.

Water locomotion and survival under water in a riparian harvestman (Opiliones, Arachnida)

Animals that live by rivers may benefit from being able to cross them, but behavioral adaptations are needed. Additionally, being able to remain submerged is also important if the animal moves under water. Here we asked whether the harvestman Heteromitobates discolor (Opiliones), that lives by rivers, (a) can propel itself across the water surface, (b) moves onto the water if disturbed and (c) can survive for long periods when submerged. Heteromitobates discolor exhibited two gaits on water, whereas a strictly terrestrial species was not able to propel itself. When experimentally submitted to simulated predator attack on a rock on the river, H. discolor walked onto the water, while a strictly terrestrial species did not. Finally, it was able to survive for 6 h under water, presumably due to the conspicuous air film that formed around its body, which was also observed in a strictly terrestrial species. Altogether, these observations suggest that the aquatic environment is not a barrier for regular activity and can be used as an extension of the terrestrial environment for H. discolor.