Microgeographic speciation in a complex of Anatolian bush crickets facilitated by fast evolution of reproductive isolation.

Identifying the drivers of microgeographic speciation (i.e., speciation over small, local geographic scales) is key to understand the origin of speciose groups. Here, we use genomic data to infer the demographic processes underlying diversification in Poecilimon luschani (Orthoptera: Tettigoniidae), a species complex belonging to the most diverse genus of bush crickets from the Mediterranean region (>170 taxa) that comprises three recognized subspecies with small allopatric distributions in the topographically complex Teke Peninsula, southwestern Anatolia. Phylogenomic reconstructions that include all other taxa within the species group confirmed that subspecies of P. luschani originated from a common ancestor during the Pleistocene, supporting recent (<1 Ma) diversification within a small geographical area (ca. 120 × 80 km). Genetic clustering analyses corroborated the distinctiveness of each subspecies and the cohesiveness of their respective populations, with abrupt genetic discontinuities coinciding with contemporary range boundaries. Indeed, our analyses uncovered the presence of two sympatric cryptic sister lineages that diverged <300 ka ago and do not admix despite being co-distributed. Collectively, these results support that all lineages within the complex represent independently evolving entities corresponding to full-fledged species. Statistical evaluation of alternative models of speciation strongly supports a scenario of divergence in isolation followed by a period of limited gene flow during the last glacial period, when all lineages experienced marked expansions according to demographic reconstructions. Our study exemplifies how localized allopatric divergence and fast evolution of reproductive isolation can promote microgeographic speciation and explain the high rates of endemism characterizing biodiversity hotspots.

Resolving the taxonomy of the Polysiphonia scopulorum complex and the Bryocladia lineage (Rhodomelaceae, Rhodophyta).

Cryptic diversity is common among marine macroalgae, with molecular tools leading to the discovery of many new species. To assign names to these morphologically similar species, the type and synonyms have to be examined, and if appropriate, new species must be described. The turf-forming red alga Polysiphonia scopulorum was originally described from Rottnest Island, Australia, and subsequently widely reported in tropical and temperate coasts based on morphological identifications. A recent study of molecular species delineation revealed a complex of 12 species in Australia, South Africa, and Europe. These species are placed in a taxonomically unresolved lineage of the tribe Polysiphonieae. The aim of this study was to resolve the genus- and species-level taxonomy of this complex and related species using molecular and morphological information. Three morphologically indistinguishable species of the complex were found at the type locality of P. scopulorum, preventing a straightforward assignment of the name to any of the molecular lineages. Therefore, we propose a molecularly characterized epitype. Polysiphonia caespitosa is reinstated for the only species found in its type locality in South Africa. We describe seven new species. Only one species of the complex can be morphologically recognized, with the other eight species indistinguishable based on morphometric analysis. The studied complex, together with another seven species currently placed in Polysiphonia and two Bryocladia species, formed a clade distinct from Polysiphonia sensu stricto. Based on observations of Bryocladia cervicornis (the generitype), we describe our seven new species in the genus Bryocladia and transfer another nine species from Polysiphonia to Bryocladia.

First evidence of lithium toxicity in the cryptic species complex of the estuarine copepod Eurytemora affinis.

The development of renewable and low-carbon energy sources means that strategic elements such as lithium (Li) are increasingly being used. The data available on the effects of Li on aquatic organisms are relatively scarce. The copepod Eurytemora affinis, widely distributed in the brackish estuarine waters of the northern hemisphere, is a species of choice in ecotoxicology but in fact constitutes a cryptic species complex, composed of at least six cryptic species. Cryptic diversity can lead to misinterpretation and alter the reproducibility of routine ecotoxicological tests. In the present study, two cryptic species of the E. affinis complex from the Seine (European clade) and the St. Lawrence (North-Atlantic clade) estuaries were used to assess Li toxicity and to compare their differential sensitivity. Larvae were exposed to different concentrations of Li (0.4, 4.39, 35.36 and 80.83 mg L-1) under semi-static conditions for 96 h. Larval development stages were determined and log-logistic functions were fitted to evaluate mortality (LC50) and growth (EC50) parameters. After 96 h of exposure, the results showed that the European and North-Atlantic clades had LC50 values of 55.33 and 67.81 mg L-1 and EC50 values of 28.94 and 41.45 mg L-1, respectively. A moderate difference in sensitivity to Li between the European and North-Atlantic clades of the E. affinis complex was observed. Thus, the cryptic species diversity should be considered using E. affinis to avoid bias in the interpretation of the data. Despite environmental concentrations of Li are expected to increase over the next years, EC50 and LC50 found for E. affinis cryptic species are largely higher than Li environmental concentrations to provoke extreme effects.

Amblyceps crassioris, a new sisoroid catfish from Odisha, India (Siluriformes: Amblycipitidae).

Amblyceps crassioris, a new species of amblycipitid catfish, is described from the Mahanadi River basin in Odisha, India. The new species can be distinguished from its congeners in having a combination of the following characters: a deeply forked caudal fin, centrally projecting hooks on proximal lepidotrichia of median caudal-fin rays absent, jaws equal in length, lateral line absent, body depth at anus 15.1%-19.5% standard length (SL), caudal peduncle depth 13.0%-18.3% SL, adipose-fin base length 21.1%-27.1% SL, eye diameter 7.35%-14.1% head length and 38 total vertebrae.

Identification of fish specimens of the Tocantins River, Brazil, using DNA barcoding.

The fish fauna of the Tocantins River possesses many endemic species; however, it is little studied in molecular terms and is quite threatened by the construction of several hydroelectric dams. Therefore, the objective of this study was to identify the ichthyofauna of the Tocantins River using DNA barcoding. For this, collections were carried out in five points of this river, which resulted in the capture of 725 individuals from which partial sequences of the cytochrome oxidase subunit I (COI) gene were obtained for genetic analysis. A total of 443 haplotypes were recovered with the mean intraspecific K2P genetic distance of 1.82%. Altogether, 138 species were identified based on morphological criteria, which was a quantity that was much lower than that indicated by the four molecular methods (assemble species by automatic partitioning [ASAP], barcode index number [BIN], generalized mixed Yule coalescent (GMYC), and Bayesian Poisson tree processes [bPTP]) through which 152-157 molecular entities were identified. In all, 41 unique BINs were obtained based on the data generated in the BOLDSystems platform. According to the result indicated by ASAP (species delimitation approach considered the most appropriate in the present study), there was an increase of 17 molecular entities (12.32%), when compared to the number of species identified through their morphological criteria, as it can show cryptic diversity, candidates for new species, and misidentifications. There were 21 incongruities indicated between the different identification approaches for species. Therefore, it is suggested that these taxonomic problems be cautiously evaluated by experts to solve such taxonomic issues.

Exploring hidden diversity: Molecular insights into the Leporinus species of the rivers of the Brazilian states of Maranhão and Piauí.

The present study delved into the world of hidden diversity by examining specimens identified as Leporinus piau from the river basins of the northern Brazilian states of Maranhão and Piauí. Using genetic analyses that combined data from three mitochondrial markers and one nuclear marker, the study identified two well-supported groups, reinforcing the findings of previous publications. The first group, found in samples from the Itapecuru, Mearim, Turiaçu, and Pericumã basins, in Maranhão, appears to represent a relatively ancient diversification and the possibility of concealed cryptic diversity. The second group, comprising specimens from the Parnaíba (Piauí) and Mearim (Maranhão) basins, appears to have resulted from a more recent process of diversification and has a close relationship with Leporinus friderici from the type locality. Our findings not only confirm the existence of a complex scenario of cryptic diversity in the genus Leporinus from the study basins but also underscore the taxonomic inconsistencies within this group of fish. This study offers a comprehensive analysis of the species diversity of the Maranhão and Piauí basins, which are critical regions for the conservation of Amazonian fish, providing valuable insights for the sustainable management and conservation of these fish.

A new discovery of cryptic species in barred sand burrower Limnichthys fasciatus (Pisces: Creediidae) from the western Pacific, with evolutionary perspectives of anti-equatorial species.

Although the barred sand burrower, Limnichthys fasciatus, is widely distributed throughout the western Pacific, including Japan, Taiwan, and Australia, its morphology and genetics are poorly known. We discovered four cryptic species of Limnichthys from the western Pacific based on mtDNA cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (rRNA) sequences. Genetic distances showed remarkably large differences (12.7%-24.3% in COI and 7.9%-19.6% in 16S rRNA) between true L. fasciatus (type locality: southeastern Australia) and the others. A relaxed clock model with optimized selected substitution models showed that their deep divergence began in the middle Miocene epoch and subsequently diverged into the current cryptic species in the Plio-Pleistocene. A eurythermal common ancestor may have evolved independently in each region due to geographical events and paleoclimatic fluctuations, which made it possible for L. fasciatus complex to be an anti-equatorial species. Despite their deep genetic divergence, they showed marked phenotypic similarity, suggesting that they have experienced similar selective pressures related to their specific behavior.

MHC class II genes mediate susceptibility and resistance to coronavirus infections in bats.

Understanding the immunogenetic basis of coronavirus (CoV) susceptibility in major pathogen reservoirs, such as bats, is central to inferring their zoonotic potential. Members of the cryptic Hipposideros bat species complex differ in CoV susceptibility, but the underlying mechanisms remain unclear. The genes of the major histocompatibility complex (MHC) are the best understood genetic basis of pathogen resistance, and differences in MHC diversity are one possible reason for asymmetrical infection patterns among closely related species. Here, we aimed to link asymmetries in observed CoV (CoV-229E, CoV-2B and CoV-2Bbasal) susceptibility to immunogenetic differences amongst four Hipposideros bat species. From the 2072 bats assigned to their respective species using the mtDNA cytochrome b gene, members of the most numerous and ubiquitous species, Hipposideros caffer D, were most infected with CoV-229E and SARS-related CoV-2B. Using a subset of 569 bats, we determined that much of the existent allelic and functional (i.e. supertype) MHC DRB class II diversity originated from common ancestry. One MHC supertype shared amongst all species, ST12, was consistently linked to susceptibility with CoV-229E, which is closely related to the common cold agent HCoV-229E, and infected bats and those carrying ST12 had a lower body condition. The same MHC supertype was connected to resistance to CoV-2B, and bats with ST12 were less likely be co-infected with CoV-229E and CoV-2B. Our work suggests a role of immunogenetics in determining CoV susceptibility in bats. We advocate for the preservation of functional genetic and species diversity in reservoirs as a means of mitigating the risk of disease spillover.

Genome-wide data reveal cryptic diversity and hybridization in a group of tree ferns.

Discovery of cryptic diversity is essential to understanding both the process of speciation and the conservation of species. Determining species boundaries in fern lineages represents a major challenge due to lack of morphologically diagnostic characters and frequent hybridization. Genomic data has substantially enhanced our understanding of the speciation process, increased the resolution of species delimitation studies, and led to the discovery of cryptic diversity. Here, we employed restriction-site-associated DNA sequencing (RAD-seq) and integrated phylogenomic and population genomic analyses to investigate phylogenetic relationships and evolutionary history of 16 tree ferns with marginate scales (Cyatheaceae) from China and Vietnam. We conducted multiple species delimitation analyses using the multispecies coalescent (MSC) model and novel approaches based on genealogical divergence index (gdi) and isolation by distance (IBD). In addition, we inferred species trees using concatenation and several coalescent-based methods, and assessed hybridization patterns and rate of gene flow across the phylogeny. We obtained highly supported and generally congruent phylogenies inferred from concatenated and summary-coalescent methods, and the monophyly of all currently recognized species were strongly supported. Our results revealed substantial evidence of cryptic diversity in three widely distributed Gymnosphaera species, each of which was composite of two highly structure lineages that may correspond to cryptic species. We found that hybridization was fairly common between not only closely related species, but also distantly related species. Collectively, it appears that scaly tree ferns may contain cryptic diversity and hybridization has played an important role throughout the evolutionary history of this group.

Seasonal Dynamics of Zygnema (Zygnematophyceae) Mats from the Austrian Alps.

Filamentous green algae of the genus Zygnema are an essential part of hydro-terrestrial ecosystems. Despite several studies on their resistance to natural stresses, little is known about the composition of their assemblages and the changes they undergo over time. Two sites at altitudes above 2200 m a.s.l. in the Austrian Alps were selected for a 2-year observation period and sampled five times. Molecular phylogenetic analysis of the 152 isolated strains of Zygnema sp. was performed based on the rbcL and trnG sequences. Seven genotypes were found at these sites during the samplings, but their proportion varied throughout the seasons. The site with a more stable water regime also had a more stable representation of genotypes, in contrast to the site with fluctuating water availability. The mats formed resistant pre-akinetes at the end of the season with reduced photosynthetic activity. Contrary to expectations, the mats were not exposed to extremely cold temperatures in winter due to snow cover. Some genotypes have been previously observed at this site, indicating that the population composition is stable. This work highlights the importance of resistant pre-akinetes in surviving winter conditions, the ability of algae to re-establish mats, and the need to address the hidden diversity of the genus Zygnema.

Multilocus approach reveals distinct evolutionary units of the South American apapa Pellona flavipinnis (Valenciennes, 1837) (Clupeiformes, Pristigasteridae).

The discovery and characterization of cryptic diversity is important for conservation and management, especially for ichthyofauna, whose diversity is underestimated and understudied. Cryptic diversity is especially common in widely distributed species, and Pellona flavipinnis is one such species. Thus, the aim of the present study was to investigate and test whether P. flavipinnis harbours cryptic diversity. In this study we used the COI and control region sequences and microsatellite loci of 86-114 specimens from 11-12 locations throughout the Amazon basin, depending on the molecular marker used. We also included two COI GenBank sequences from the type locality of the species, the Paraná River. The results from COI sequences showed that P. flavipinnis from the Amazon basin presented two spatially structured lineages differentiated from P. flavipinnis from the Paraná River by 10.6%-9.8% (depending on the lineages) and 45 mutational steps. The genetic distance between the Amazon lineages was 2.4% using COI, with high population differentiation values (ФST = 0.8686 and ФST = 0.8483 for COI and control region, respectively). Among the five species delimitation methods employed, three indicated two lineages in P. flavipinnis in the Amazon basin, and all five methods indicated that the Amazonian lineages are different from that of Paraná. Results from microsatellite loci also showed that P. flavipinnis from the Amazon basin is composed of two evolutionary units. The results of 13 morphometric measurements indicated that there are no differences in shape between the P. flavipinnis lineages in the Amazon basin. The present findings suggest that there are two sympatric lineages of P. flavipinnis in the Amazon basin.

The first phylogenetic and species delimitation study of the nudibranch genus Gymnodoris reveals high species diversity (Gastropoda: Nudibranchia).

Nudibranchs are charismatic marine gastropods that lack a shell in the adult stage. While most nudibranchs feed on sessile animals such as sponges, bryozoans, and cnidarians, the nudibranch genus Gymnodoris Stimpson, 1855 evolved a more active and predatory lifestyle, including sea slug predation, cannibalism, and oddly enough, fish-fin parasitism. At the beginning of our work, no phylogenetic hypothesis existed for the genus, nor a clear picture of how Gymnodoris is related to other nudibranchs. Here we set out to reconstruct Gymnodoris phylogeny, investigate species diversity, and clarify the status of the genus name Analogium, which had been proposed for members of the genus with a linear gill filament arrangement. We present the first phylogenetic hypothesis for Gymnodoris, reconstructed by maximum likelihood and Bayesian inference using two mitochondrial and two nuclear loci, with gill filament arrangement plotted on the phylogeny. The backbone of the phylogeny remains unresolved with theseloci, however, we found that Gymnodoris comprises three main well-supported clades, which we refer to as the "subornata", "citrina" and "varied" clade, the latter two clades being comprised of several well-supported subclades. The sister group to Gymnodoris is a clade including the genera Vayssierea and Lecithophorus. Based on ABGD and PTP species delimitation methods, we conservatively estimate 65-70 species comprise our dataset. We further estimate that approximately 81% of the species we sampled are undescribed, and note that a linear gill filament arrangement has evolved multiple times within the genus. Gymnodoris is only monophyletic when the species with a linear gill arrangement are included. Therefore, at this time, we agree with the synonymy of Analogium striata with Gymnodoris striata by Rudman and Darvell (1990) and that the genus name Analogium is warranted as a junior synonym of Gymnodoris. Given the extensive undescribed diversity, and lack of resolution at some of the nodes in the phylogeny, patterns of diversification in diet are impossible to discern at this time and will require a large effort to both describe Gymnodoris species diversity and the diets of these candidate species.

A multi-locus approach to elucidating the evolutionary history of the clingfish Tomicodon petersii (Gobiesocidae) in the Tropical Eastern Pacific.

Marine species that are widely distributed in the Tropical Eastern Pacific (TEP) has served as a model for studying biogeographic patterns resulting from the effects of intraregional habitat discontinuities and oceanographic processes on the diversification and evolution of cryptobenthic reef fishes. Tomicodon petersii, a clingfish (Gobiesocidae) endemic to the TEP, is found on very shallow rocky reefs from central Mexico to northern Peru, and in the Cocos and Galapagos islands. We evaluated the effect of likely biogeographic barriers in different parts of the TEP on the diversification process of this species. We used one mitochondrial and three nuclear DNA markers from 112 individuals collected across the distribution range of T. petersii. Our phylogenetic results showed the samples constituted a monophyletic group, with three well-supported, allopatric subgroups: in the Mexican province, the Panamic province (from El Salvador to Ecuador), and the Galapagos Islands. The split between the Mexican and more southerly clades was estimated to occur at the end of the Miocene ca. 5.74 Mya, and the subsequent cladogenetic event separating the Galapagos population from the Panamic population at the junction of the Pliocene and Pleistocene, ca. 2.85 Mya. The species tree, Bayesian species delimitation tests (BPP), STACEY, and substantial genetic distances separating these three populations indicate that these three independent evolutionary units likely include two unnamed species. The cladogenetic events that promoted the formation of those genetically differentiated groups are consistent with disruptive effects on gene flow of habitat discontinuities and oceanographic processes along the mainland shoreline in the TEP and of ocean-island isolation, in conjunction with the species intrinsic life-history characteristics.

Ecological divergence and synchronous Pleistocene diversification in the widespread South American butter frog complex.

Phylogeographic studies primarily focus on the major role of landscape topography in driving lineage diversification. However, populational phylogeographic breaks may also occur as a result of either niche conservatism or divergence, in the absence of geographic barriers to gene flow. Furthermore, these two factors are not mutually exclusive and can act in concert, making it challenging to evaluate their relative importances on explaining genetic variation in nature. Herein, we use sequences of two mitochondrial and four nuclear genes to investigate the timing and diversification patterns of species pertaining to the Leptodactylus latrans complex, which harbors four morphologically cryptic species with broad distributions across environmental gradients in eastern South America. The origin of this species complex dates back to the late Miocene (ca. 5.5 Mya), but most diversification events occurred synchronically during the late Pleistocene likely as the result of ecological divergence driven by Quaternary climatic oscillations. Further, significant patterns of environmental niche divergences among species in the L. latrans complex imply that ecological isolation is the primary mode of genetic diversification, mostly because phylogenetic breaks are associated with environmental transitions rather than topographic barriers at both species and populational scales. We provided new insights about diversification patterns and processes within a species complex of broadly and continuously distributed group of frogs along South America.

Evolutionary convergence in body shape obscures taxonomic diversity in species of the African Labeo forskalii group: Case study of L. parvus Boulenger 1902 and L. ogunensis Boulenger 1910.

Labeo is the third most diverse genus of African cyprinids and is widely distributed across the continent. Labeo parvus, a small species originally described from the Congo basin, has been considered the only species of the L. forskalii group distributed across five African ichthyofaunal provinces (Nilo-Sudan, Congo, Cuanza, and Upper and Lower Guinea). However, morphological similarity between L. parvus and numerous congeners remains a central cause of taxonomic confusion within the genus. Here we employed a phylogenetic comparative approach to assess phenotypic convergence among species of the L. forskalii group, investigate the taxonomic status of L. parvus sensu lato (sl) in west Africa, and reevaluate the composition and distribution of L. parvus sensu stricto (ss). Our phylogenetic analysis provides no support for a sister relationship between L. parvus ss and any of the west African Labeo parvus-like species. Geometric morphometric and molecular phylogenetic data indicate that L. parvus ss is a Congo basin endemic, and seemingly ecologically equivalent species found in west Africa are L. ogunensis, L. obscurus and other undescribed or previously synonymized species. We discuss our findings in terms of convergent evolution using phylomorphospace and tests for phylogenetic signal.

A new species of Hoplias malabaricus species complex (Characiformes: Erythrinidae) from the Crepori River, Amazon basin, Brazil.

A new species belonging to the Hoplias malabaricus complex from the Amazon basin, Brazil, is described. The new species is characterized by 15-16 predorsal scales, 37-39 lateral-line scales, 5 scales from dorsal fin to lateral line, 38-39 vertebrae, iii-iv, 7-8 anal-fin rays, ii-iv, 12-15 caudal-fin rays, last vertical series of scales on the base of caudal-fin rays forming a straight line, 6-7 dark bands in anal fin and no distinctive dark bands or blotches on flanks. The new species is also distinguished from other congeners of the H. malabaricus species-group by means of landmark-based morphometrics and DNA Barcoding (Cytochrome c Oxidase I gene). An identification key to species of the H. malabaricus species complex is provided.

An evaluation of errors in the mitochondrial COI sequences of Hydrachnidia (Acari, Parasitengona) in public databases.

Public molecular databases are fundamental tools for modern taxonomic studies whose usefulness rely on the soundness of the data within them. Here, we study potential errors that can arise along the data pipeline from sampling, specimen identification and molecular processing (digestion, amplification and sequencing) to the submission of sequences to these databases by using the DNA sequences of Hydrachnidia (Acari, Parasitengona) as a case study. Our results indicate that molecular information is available for only about 3% of the Hydrachnidia species known to date; yet, within this small percentage, errors are present in almost 5% of the species analyzed (0.5% of the sequences and almost 11% of the genera). This study underscores the scarcity of genetic data available for Hydrachnidia, but also that the proportion of errors in DNA sequences is relatively small. Even so, it highlights the danger associated with using DNA sequences from public databases, particularly for species identification, and reinforces the need for greater quality control measures and/or protocols to avoid an intensification of errors in the (post) genomics era. Finally, our study emphasizes that potential errors may also reveal cryptic diversity within a species.

Volcanism and palaeoclimate change drive diversification of the world's largest whip spider (Amblypygi).

The tropics contain many of the most biodiverse regions on Earth but the processes responsible for generating this diversity remain poorly understood. This study investigated the drivers of diversification in arthropods with stenotopic ecological requirements and limited dispersal capability using as a model the monotypic whip spider (Amblypygi) genus Acanthophrynus, widespread in the tropical deciduous forests of Mexico. We hypothesized that for these organisms, the tropical deciduous forests serve as a conduit for dispersal, with their disappearance imposing barriers. Given that these forests are located in a region of complex geological history and that they fluctuated in extent during the Pliocene-Pleistocene glacial/interglacial cycles we combine molecular divergence dating, palaeoclimatic niche modelling and ancestral area reconstruction to test if and when habitat fragmentation promoted diversification in Acanthophrynus. Concomitant with the expected role of landscape change, we demonstrate that orogeny of the Trans-Mexican Volcanic Belt, in the Late Miocene or Early Pliocene (6.95-5.21 million years ago), drove the earliest divergence of Acanthophrynus by vicariance. Similarly, as expected, the later onset of glaciations strongly impacted diversification. Whereas a more stable climate in the southern part of the distribution enabled further diversification, a marked loss of suitable habitat during the glaciations only allowed dispersal and diversification in the north to occur later, resulting in a lower overall diversity in this region. Barriers and diversification patterns identified in Acanthophrynus are reflected in the phylogeography of codistributed vertebrates and arthropods, emphasizing the profound impact of Trans-Mexican Volcanic Belt orogeny and glacial/interglacial cycles as drivers of diversification in the Mexican Neotropics.

Comprehensive phylogeny of Myrmecocystus honey ants highlights cryptic diversity and infers evolution during aridification of the American Southwest.

The New World ant genus Myrmecocystus Wesmael, 1838 (Formicidae: Formicinae: Lasiini) is endemic to arid and semi-arid habitats of the western United States and Mexico. Several intriguing life history traits have been described for the genus, the best-known of which are replete workers, that store liquified food in their largely expanded crops and are colloquially referred to as "honeypots". Despite their interesting biology and ecological importance for arid ecosystems, the evolutionary history of Myrmecocystus ants is largely unknown and the current taxonomy presents an unsatisfactory systematic framework. We use ultraconserved elements to infer the evolutionary history of Myrmecocystus ants and provide a comprehensive, dated phylogenetic framework that clarifies the molecular systematics within the genus with high statistical support, reveals cryptic diversity, and reconstructs ancestral foraging activity. Using maximum likelihood, Bayesian and species tree approaches on a data set of 134 ingroup specimens (including samples from natural history collections and type material), we recover largely identical topologies that leave the position of only few clades uncertain and cover the intra- and interspecific variation of 28 of the 29 described and six undescribed species. In addition to traditional support values, such as bootstrap and posterior probability, we quantify genealogical concordance to estimate the effects of conflicting evolutionary histories on phylogenetic inference. Our analyses reveal that the current taxonomic classification of the genus is inconsistent with the molecular phylogenetic inference, and we identify cryptic diversity in seven species. Divergence dating suggests that the split between Myrmecocystus and its sister taxon Lasius occurred in the early Miocene. Crown group Myrmecocystus started diversifying about 14.08 Ma ago when the gradual aridification of the southwestern United States and northern Mexico led to formation of the American deserts and to adaptive radiations of many desert taxa.

Geographic restriction, genetic divergence, and morphological disparity in the Brazilian Atlantic Forests: Insights from Leposoma lizards (Gymnophthalmidae, Squamata).

Lineage differentiation, long-term persistence, and range limitation promote high levels of phylogenetic and phylogeographic endemisms and likely underlie the abundant morphologically cryptic diversity observed in the Brazilian Atlantic Forests (AF). We explore lineage differentiation and range restriction in the AF and ask if genetic divergence and morphological disparity are correlated by integrating coalescent-based species delimitation, molecular phylogenetic, and morphological analyses in the lizard genus Leposoma. We present the first species tree for Leposoma and of their tribe, the Ecpleopodini. The analyses are based on the largest dataset ever assembled for Leposoma in terms of number of species (all represented), genetic markers (12 loci), and geographic coverage (~2,500 km). The exercise allows us to robustly delimit species within the genus and phylogeographic lineages within all species. We find support for the monophyly of the genus and for the recognition of a yet undescribed species around the Baía de Todos-os-Santos, in the state of Bahia; this form is distinct from all other congeners, both genetically and morphologically. We find that L. baturitensis, from the northeastern state of Ceará, is basal to the genus - and sister to a clade of six species restricted to the AF across the eastern coast of Brazil. Relationships within this coastal clade are ((((L. annectans, Leposoma sp.), L. scincoides), L. puk) (L. nanodactylus, L. sinepollex)). Phylogenetic and phylogeographic analyses, together with precise distribution data, allowed us to update the ranges of species and phylogeographic lineages. We reveal pervasive geographic restriction of divergent lineages in Leposoma at and below species level and discuss how forest refuges and rivers might have contributed to it. We find that morphological disparity lags behind genetic divergence in the genus because although they are correlated, the first accumulates at a much slower rate than the latter. We hope to encourage new studies in the area of AF north of the Doce river; phylogeographic sampling in that region has been much less common relative to southern sites, yet it may hold the key to several important processes defining biodiversity patterns in eastern Brazil. This appears to specially apply to processes underlying geographic restriction of morphologically cryptic, yet genetic divergent lineages, as the case of Leposoma.