Many studies propose that Quaternary climatic cycles contracted and/or expanded the ranges of species and biomes. Strong expansion-contraction dynamics of biomes presume concerted demographic changes of associated fauna. The analysis of temporal concordance of demographic changes can be used to test the influence of Quaternary climate on diversification processes. Hierarchical approximate Bayesian computation (hABC) is a powerful and flexible approach that models genetic data from multiple species, and can be used to estimate the temporal concordance of demographic processes. Using available single-locus data, we can now perform large-scale analyses, both in terms of number of species and geographic scope. Here, we first compared the power of four alternative hABC models for a collection of single-locus data. We found that the model incorporating an a priori hypothesis about the timing of simultaneous demographic change had the best performance. Second, we applied the hABC models to a data set of seven squamate and four amphibian species occurring in the Seasonally Dry Tropical Forests (Caatinga) in northeastern Brazil, which, according to paleoclimatic evidence, experienced an increase in aridity during the Pleistocene. If this increase was important for the diversification of associated xeric-adapted species, simultaneous population expansions should be evident at the community level. We found a strong signal of synchronous population expansion in the Late Pleistocene, supporting the increase of the Caatinga during this time. This expansion likely enhanced the formation of communities adapted to high aridity and seasonality and caused regional extirpation of taxa adapted to wet forest.

Aim: To assess the effects of historical events on the tempo and mode of diversification of the lizard Polychrus acutirostris along the South American diagonal of open formations (DOF).Location: Caatinga and Cerrado biomes in Brazil. Methods:We sequenced fragments of one mtDNA and three nuDNA genes of 68 individuals from 33 localities. We used population assignment methods to access genetic structure and estimate lineage boundaries. Next, we estimated lineage relationships, intraspecific diversity, environmental niche similarity and demographic history. Finally, we tested 12 diversification scenarios using an approximate Bayesian computation (ABC) approach. Results:We recovered three non-overlapping, geographically structured lineages corresponding to Caatinga, north-east Cerrado and south-west Cerrado, with the major divergence event dating to the Late Neogene. We also recovered a complex scenario of divergence associated with gene flow and niche divergence. Main conclusions:We show a complex history of diversification along the South American DOF. Our findings support the role of environmental features as the likely drivers of P. acutirostris intraspecific diversification during the Late Neogene. K E Y W O R D Sapproximate Bayesian computation, Caatinga, Cerrado, phylogeography, Polychrus acutirostris,

The Pleistocenic Arc Hypothesis (PAH) posits that South American Seasonally Dry Tropical Forests (SDTF) were interconnected during Pleistocene glacial periods, enabling the expansion of species ranges that were subsequently fragmented in interglacial periods, promoting speciation. The lizard genus Lygodactylus occurs in Africa, Madagascar, and South America. Compared to the high diversity of African Lygodactylus, only two species are known to occur in South America, L. klugei and L. wetzeli, distributed in SDTFs and the Chaco, respectively. We use a phylogenetic approach based on mitochondrial (ND2) and nuclear (RAG-1) markers covering the known range of South American Lygodactylus to investigate (i) if they are monophyletic relative to their African congeners, (ii) if their divergence is congruent with the fragmentation of the PAH, and (iii) if cryptic diversity exists within currently recognized species. Maximum likelihood and Bayesian phylogenetic analyses recovered a well-supported monophyletic South American Lygodactylus, presumably resulting from a single trans-Atlantic dispersal event 29 Mya. Species delimitation analyses supported the existence of five putative species, three of them undescribed. Divergence times among L. klugei and the three putative undescribed species, all endemic to the SDTFs, are not congruent with the fragmentation of the PAH. However, fragmentation of the once broader and continuous SDTFs likely influenced the divergence of L. wetzeli in the Chaco and Lygodactylus sp. 3 (in a SDTF enclave in the Cerrado).

Table 1. Species used in analysis. For each species, the scientific name, type of organism, type of data, number of sequences, and reference of original publication is shown. SpeciesBroad Taxon Type of Data # sequences Original publication Bryopsis sp. Green Algae cpDNA 66 Krellwitz et al. (2001) Gracilaria tikvahiae Red Algae cpDNA 20 Gurgel et al.(2004) Xerula furfuracea Fungi nuDNA 41 Yang et al.(2009) & Petersen and Hughes (2010) & Hao et al.(2016) Sphagnum bartlettianum Bryophyta cpDNA + nuDNA 12 Shaw et al.(2005) Acer rubrum Angiosperm cpDNA 38 McLachlan et al.(2005) Apios americana Angiosperm nuDNA 18 Joly & Bruneau (2004) Dicerandra spp Angiosperm cpDNA 30 Oliveira et al.(2007) Fagus grandifolia Angiosperm cpDNA 23 McLachlan et al.(2005) Liquidambar styraciflua Angiosperm cpDNA 109 Morris et al.(2008) Prunus spp Angiosperm cpDNA 226 Shaw & Small (2005) Tilia americana Angiosperm cpDNA 297 McCarthy and Mason-Gamer (2016) Trillium cuneatum Angiosperm cpDNA 281 Gonzales et al.(2008) Uniola paniculata Angiosperm cpDNA 131 Hodel & Gonzales (2013) Bugula neritina Bryozoa mtDNA 30 McGovern & Hellberg (2003) Daphnia obtusa Crustacean mtDNA 36 Penton et al.(2004) Emerita talpoida Crustacean mtDNA 4 Tam et al.(1996) Farfantepenaeus aztecus Crustacean mtDNA 76 McMillen-Jackson and Bert (2003) Litopenaeus setiferus Crustacean mtDNA 92 McMillen-Jackson and Bert (2003) & Maggioni et al. (2001) &Vazquez-Bader et al.(2004) & Bremer et al.(2010) Pagarus longicarpus Crustacean mtDNA 67 Young et al.(2002) Pagarus pollicaris Crustacean mtDNA 13 Young et al.(2002) Busycon sinistrum Gastropod mtDNA 31 Wise et al.(2004) Lampsilis altilis Mollusk mtDNA 5 Roe et al.(2001) Lampsilis australis Mollusk mtDNA 5 Roe et al.(2001) Lampsilis ovata Mollusk mtDNA 2 Roe et al.(2001) & Campbell et al.(2005) Lampsilis perovalis Mollusk mtDNA 5 Roe et al.(2001) Lampsilis teres Mollusk mtDNA 2 Roe et al.(2001) & Lydeard et al.(2000) Spisula solidissima Mollusk mtDNA 52 Hare and Weinberg (2005) Ambystoma tigrinum Amphibian mtDNA 56 Church et al.(2003) Desmognathus wrightii Amphibian mtDNA 29 Crespi et al.(2003) Eumeces fasciatus Amphibian mtDNA 82 Howes et al.(2006) Eurycea bislineata Amphibian mtDNA 56 Kozak et al.(2006) Eurycea cirrigera Amphibian mtDNA 251 Kozak et al.(2006) Eurycea junaluska Amphibian mtDNA 6 Kozak et al.(2006) Eurycea multiplicata Amphibian mtDNA 46 Bonett & Chippindale (2004) Eurycea tymerensis Amphibian mtDNA 16 Bonett & Chippindale (2004) Eurycea wilderae Amphibian mtDNA 129 Kozak et al.(2006)

No abstract

Species diversification can be strongly influenced by geomorphological features, such as mountains, valleys and rivers. Rivers can act as hard or soft barriers to gene flow depending on their size, speed of flow, historical dynamics and regional topographical characteristics. The São Francisco River (SFR) is the largest perennial river in the Caatinga biome in north-eastern Brazil and has been considered a barrier to gene flow and dispersal. Herein, we evaluated the role of the SFR on the evolution of Lygodactylus klugei, a small gecko from the Caatinga. Using a single-locus species delimitation method (generalized mixed Yule coalescent), we defined lineages (haploclades). Subsequently, we evaluated the role of the SFR in structuring genetic diversity in this species using a multilocus approach to quantify migration across margins. We also evaluated genetic structure based on nuclear markers, testing the number of populations found through an assignment test (STRUCTURE) across the species distribution. We recovered two mitochondrial lineages structured with respect to the SFR, but only a single population was inferred from nuclear markers. Given that we detected an influence of the SFR only on mitochondrial markers, we suggest that the current river course has acted as a relatively recent geographical barrier for L. klugei, for ~450 000 years.

The Neotropics are one of the richest regions in biodiversity globally. Still, much remains unknown about the mechanisms and processes responsible for the accumulation of species in this region. Among the many limitations on our current knowledge on the region's biodiversity, understanding of community composition and species distributions is limited and greatly biased in many Brazilian regions. We present information on species composition, habitat use, geographic distribution, taxonomic accounts, and conservation of snakes from Rio Grande do Norte state, Northeastern Brazil. We compiled, from primary and literature data, 851 snake records from seven families and 47 species, with fi ve new records for the state. Species are mainly terrestrial and semi-arboreal and associated with at least six vegetation types from Caatinga and Atlantic Forest domains. None of the species is listed in threatened categories of IUCN, while two species are listed in the Brazilian Threatened Fauna list. Our data covers 32.34% of the state's area, a consequence of locally limited inventories and lack of longterm studies on snakes' fauna. The richest areas within the state are near large cities, which lack protected areas for the species they harbor, and highlights the necessity of protective policies and conservation actions.

Aim: Species adapt differently to contrasting environments, such as open habitats with sparse vegetation and forested habitats with dense forest cover. We investigated colonization patterns in the open and forested environments in the diagonal of open formations and surrounding rain forests (i.e. Amazonia and Atlantic Forest) in Brazil, tested whether the diversification rates were affected by the environmental conditions and identified traits that enabled species to persist in those environments.