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The processes that restrict gene flow between populations are fundamental to speciation. Here, we develop a simple framework for studying whether divergence in morphology, climatic niche, time and space contribute to reduced gene flow among populations and species. We apply this framework to a model system involving a clade of spiny lizards (Sceloporus) occurring mostly in northeastern Mexico, which show striking variation in morphology and habitat among closely related species and populations. We developed a new time-calibrated phylogeny for the group using RADseq data from 152 individuals. This phylogeny identified 12 putative species-level clades, including at least two undescribed species. We then estimated levels of gene flow among 21 geographically adjacent pairs of species and populations. We also estimated divergence in morphological and climatic niche variables among these same pairs, along with divergence times and geographic distances. Using Bayesian generalised linear models, we found that gene flow between pairs of lineages is negatively related to divergence time and morphological divergence among them (which are uncorrelated), and not to geographic distance or climatic divergence. The framework used here can be applied to study speciation in many other organisms having genomic data but lacking direct data on reproductive isolation. We also found several other intriguing patterns in this system, including the parallel evolution of a strikingly similar montane blue-red morph from more dull-coloured desert ancestors within two different, nonsister species., (© 2024 The Author(s). Molecular Ecology published by John Wiley & Sons Ltd.)

The genus Mixcoatlus is composed of three species: Mixcoatlus barbouri, M. browni, and M. melanurus, of which the venom composition of M. melanurus, the most common species of the three, has only recently been described. However, very little is known about the natural history of M. barbouri and M. browni, and the venom composition of these two species has remained thus far unexplored. In this study we characterize the proteomic profiles and the main biochemical and toxic activities of these two venoms. Proteomic data obtained by shotgun analysis of whole venom identified 12 protein families for M. barbouri, and 13 for M. browni. The latter venom was further characterized by using a quantitative 'venomics' protocol, which revealed that it is mainly composed of 51.1 % phospholipases A 2 (PLA 2 ), 25.5 % snake venom serine proteases (SVSP), 4.6 % l-amino oxidases (LAO), and 3.6 % snake venom metalloproteases (SVMP), with lower percentages other six protein families. Both venoms contained homologs of the basic and acidic subunits of crotoxin. However, due to limitations in M. barbouri venom availability, we could only characterize the crotoxin-like protein of M. browni venom, which we have named Mixcoatlutoxin. It exhibited a lethal potency in mice like that described for classical rattlesnake crotoxins. These findings expand knowledge on the distribution of crotoxin-like heterodimeric proteins in viper snake species. Further investigation of the bioactivities of the venom of M. barbouri, on the other hand, remains necessary., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Multiple geological and climatic events have created geographical or ecological barriers associated with speciation events, playing a role in biological diversification in North and Central America. Here, we evaluate the influence of the Neogene and Quaternary geological events, as well as the climatic changes in the diversification of the colubrid snake genus Rhadinaea using molecular dating and ancestral area reconstruction. A multilocus sequence dataset was generated for 37 individuals of Rhadinaea from most of the biogeographical provinces where the genus is distributed, representing 19 of the 21 currently recognized species, and two undescribed species. Our analyses show that the majority of the Rhadinaea species nest in two main clades, herein identified as "Eastern" and "Southern". These clades probably diverged from each other in the early Miocene, and their divergence was followed by 11 divergences during the middle to late Miocene, three divergences during the Pliocene, and six divergences in the Pleistocene. The ancestral distribution of Rhadinaea was reconstructed across the Sierra Madre del Sur. Our phylogenetic analyses do not support the monophyly of Rhadinaea . The Miocene and Pliocene geomorphology, perhaps in conjunction with climate change, appears to have triggered the diversification of the genus, while the climatic changes during the Miocene probably induced the diversification of Rhadinaea in the Sierra Madre del Sur. Our analysis suggests that the uplifting of the Trans-Mexican Volcanic Belt and Chiapan-Guatemalan highlands in this same period resulted in northward and southward colonization events. This was followed by more recent, independent colonization events in the Pliocene and Pleistocene involving the Balsas Basin, Chihuahuan Desert, Pacific Coast, Sierra Madre Occidental, Sierra Madre Oriental, Sierra Madre del Sur, Trans-Mexican Volcanic Belt, and Veracruz provinces, probably driven by the climatic fluctuations of the time., Competing Interests: The authors Uriel Alonso García Sotelo, Uri Omar García Vázquez, and David Nahum Espinosa Organista declare that we have no significant competing financial, professional, or personal interests that might have influenced the performance or presentation of the work described in this manuscript., (© 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

We transfer Apodemia planeca R. de la Maza E. J. de la Maza E. 2017 to Emesis as Emesis planeca (R. de la Maza E. J. de la Maza E.) n. comb. based on phylogenetic hypotheses estimated with one mtDNA and two nDNA markers. This is a rare and poorly known metalmark, endemic to the central region of Balsas Basin in Michoacán, Mexico, originally described from material collected 23 years ago. Here we analyze new specimens from the type locality not included in the original description. With this new material, we describe the morphological variation of adults, including male and female genitalia. This variation is then discussed and compared with the original description. Emesis planeca n. comb. is restricted to the Tropical Deciduous Forest and the adults fly only in the dry season. Due to the spatial, temporal, and ecological rareness of Emesis planeca n. comb., considering it has not been collected in more than two decades and that the Tropical Deciduous Forest is one of the most threatened habitats in Mexico; we propose assigning a protection status to this species.

Tribe Emesidini Seraphim, Freitas Kaminski (Lepidoptera: Riodinidae) is distributed in America from southwest Canada to Brazil and Paraguay, and includes 57 species and 54 subspecies (Callaghan Lamas 2004; Penz DeVries 2006; Gallard 2008; Pelham 2008; De la Maza De la Maza 2017 a,b; Kaminski et al. 2017; Seraphim et al. 2018; Trujano-Ortega et al. 2018; Zhang et al. 2019). The tribe has great taxonomic, morphological and ecological diversity, as well as wide geographic and seasonal variation. This great variation and broad geographic range of some genera entail the need for a taxonomic review (Espeland et al. 2015; Trujano-Ortega et al. 2018).

The genus Rhadinaea is a diverse clade of New World dipsadid snakes, with 22 species arranged in six recognized species groups. The most recently described species, Rhadinaea eduardoi , was described based on a unique specimen collected in the Santa Catarina Juquila municipality in the Sierra Madre del Sur of southern Oaxaca, Mexico. Here, based on a reexamination of the holotype and the results of a phylogenetic analysis of the holotype of Rhadinaea eduardoi and representatives of several genera closely related to Rhadinaea , we reassessed the generic assignment of Rhadinaea eduardoi . In our phylogenetic hypothesis, R. eduardoi was nested within a strongly supported clade of Coniophanes fissidens samples, thus making Rhadinaea paraphyletic with respect to Coniophanes . Additionally, our reexamination of the holotype of Rhadinaea eduardoi revealed that the alleged presence of a subpreocular scale is only true on the right side of the head, and that this scale appears to be a malformed preocular scale; also, a reduction in dorsal scale rows is present; and posterior enlarged maxillary teeth are grooved. Herein we consider that Rhadinaea eduardoi should be placed in the synonymy of Coniophanes fissidens . Consequently, we recognized only five species groups within the genus Rhadinaea ., (Ricardo Palacios-Aguilar, Uri Omar García-Vázquez.)

Introgression is now commonly reported in studies across the Tree of Life, aided by recent advancements in data collection and analysis. Nevertheless, researchers working with nonmodel species lacking reference genomes may be stymied by a mismatch between available resources and methodological demands. In this study, we demonstrate a fast and simple approach for inferring introgression using RADseq data, and apply it to a case study involving spiny lizards (Sceloporus) from northeastern México. First, we find evidence for recurrent mtDNA introgression between the two focal species based on patterns of mito-nuclear discordance. We then test for nuclear introgression by exhaustively applying the "five-taxon" D-statistic (D FOIL ) to all relevant individuals sampled for RADseq data. In our case, this exhaustive approach (dubbed "ExD FOIL ") entails testing up to ~250,000 unique four-taxon combinations of individuals across species. To facilitate use of this ExD FOIL approach, we provide scripts for many relevant tasks, including the selection of appropriate four-taxon combinations, execution of D FOIL tests in parallel and visualization of introgression results in phylogenetic and geographic space. Using ExD FOIL , we find evidence for ancient introgression between the focal species. Furthermore, we reveal geographic variation in patterns of introgression that is consistent with patterns of mito-nuclear discordance and with recurrent introgression. Overall, our study demonstrates that the combination of D FOIL and RADseq data can effectively detect introgression under a variety of sampling conditions (for individuals, populations and loci). Importantly, we also find evidence that batch-specific error and linkage in RADseq data may mislead inferences of introgression under certain conditions., (© 2018 John Wiley & Sons Ltd.)

Integrative taxonomy has been generally considered as a goal in systematics for more than a decade. Here, we employed environmental, molecular, and morphological data to evaluate the species boundaries within the short-nosed skink Plestiodon brevirostris from south-central Mexico, one member of the morphologically conservative P. brevirostris group. Our molecular dataset includes one mitochondrial and two nuclear loci. The mitochondrial fragment includes the full length of the gene coding for the NADH dehydrogenase subunit 1 protein, a segment of the gene coding for 16S ribosomal RNA, and flanking tRNAs. The nuclear dataset includes fragments of the genes coding for the megakaryoblastic leukemia 1 and RNA fingerprint 35 proteins. We employed phylogenetic reconstruction, analyses of population structure and morphological variation, and species delimitation methods (including the integration of the three kinds of data in a unified probabilistic framework) to evaluate species limits. Our results suggest that P. brevirostris represents four distinct species. The information provided by each kind of data allowed us to discern between alternative explanations for the observed patterns of geographic structure. Two of the newly recognized lineages are poorly differentiated morphologically but apparently differ in environmental preferences and are allopatric. Additionally, one lineage is microendemic and parapatric with respect to another one. Moreover, our phylogenetic analyses suggest that other taxa within the P. brevirostris group may represent species complexes. We discuss our results in the context of integrative species delimitation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A new species of the Rhadinaeadecorata group is described based on two specimens from the Sierra Madre del Sur, Guerrero, Mexico. The new species differs from all other members of the genus Rhadinaea by having: eight supralabials; 149-151 (male) ventrals; 63-77 (male) subcaudals; two large pale nuchal blotches, forming an incomplete collar that occupies two scales laterally and is bissected along the dorsal midline; a postocular pale marking consisting of a well-defined, narrow line beginning behind the upper posterior margin of the eye and extending posteriorly nearly horizontally until connecting with the nuchal blotches; and the dark ground color of the flanks extending to the lateral portion of the ventrals. The large nuchal blotches distinguish the new species from the other members of the R.decorata group, except for R.cuneata and some individuals of R.hesperia (pale nuchal marking one-scale wide in R.marcellae , absent in the other species). The condition of the postocular pale marking distinguishes it from R.cuneata and R.hesperia (postocular pale marking wedge-shaped in R.cuneata , not connected with the pale post-cephalic markings in R.hesperia ). Furthermore, the number of subcaudals and the coloration of the lateral portion of the ventrals distinguish it from R.omiltemana and R.taeniata , the remaining congeners found in Guerrero (85-90 in males of R.omiltemana and 91-121 in R.taeniata ; dark color of the flanks not reaching ventrals in the former species, occasionally and faintly in R.taeniata ). Additionally, a new combination for R.stadelmani is proposed. The new species is the first described in the genus Rhadinaea in more than 40 years.

A new species of hylid frog is described from the southwestern edge of the Mexican Plateau from the states of Morelos and Mexico through Michoacán and Jalisco, reaching the Sierra Madre Occidental in Sinaloa and western Durango. The new species is part of the widespread Mexican hylid Sarcohyla bistincta (sensu amplo) complex, comprised of S. bistincta, S. pentheter, S. calthula, and S. ephemera. One subspecies of S. bistincta (labeculata) was proposed for an isolated population in Oaxaca. We restrict the group's nominal species, S. bistincta (sensu stricto), to the Sierra Madre Oriental of Mexico and southward into the Sierra Madre del Sur of Guerrero and Oaxaca. Examination of type material places S. calthula and S. ephemera in the synonymy of S. labeculata (new combination). The species allied to S. bistincta, namely, S. bistincta, S. labeculata, S. pentheter, and the new species described herein, are diagnosed and described following recent suggested taxonomic changes and new available material.

Two new genera of Riodinidae (Insecta: Lepidoptera) are described, Neoapodemia Trujano-Ortega, gen. n. ( Neoapodemia nais (W. H. Edwards, 1876), comb. n. , N. chisosensis Freeman, 1964, comb. n. ) and Plesioarida Trujano-Ortega & García-Vázquez, gen. n. ( Plesioarida palmerii palmerii (W. H. Edwards, 1870), comb. n. , P. palmerii arizona (Austin, [1989]), comb. n. , P. palmerii australis (Austin, [1989]), comb. n. , P. hepburni hepburni (Godman & Salvin, 1886), comb. n. , P. hepburni remota (Austin, 1991), comb. n. , P. murphyi (Austin, [1989]), comb. n. , P. hypoglauca hypoglauca (Godman & Salvin, 1878), comb. n. , P. hypoglauca wellingi (Ferris, 1985), comb. n. , P. walkeri (Godman & Salvin, 1886), comb. n. , P. selvatica (De la Maza & De la Maza, 2017), comb. n. ). Neoapodemia Trujano-Ortega, gen. n. is distributed in the southwestern USA and northeastern Mexico, while Plesioarida Trujano-Ortega & García-Vázquez, gen. n. is present from the southern USA to Central America. Species of these genera were previously classified as Apodemia C. Felder & R. Felder but molecular and morphological evidence separate them as new taxa. Morphological diagnoses and descriptions are provided for both new genera, including the main distinctive characters from labial palpi, prothoracic legs, wing venation and genitalia, as well as life history traits. A molecular phylogeny of one mitochondrial gene (COI) and two nuclear genes (EF-1a and wg) are also presented of most species of Apodemia , Neoapodemia Trujano-Ortega, gen. n. , Plesioarida Trujano-Ortega & García-Vázquez, gen. n. , and sequences of specimens from all tribes of Riodinidae. We compare the characters of Apodemia , Neoapodemia Trujano-Ortega, gen. n. and Plesioarida Trujano-Ortega & García-Vázquez, gen. n. and discuss the differences that support the description of these new taxa. This is a contribution to the taxonomy of the Riodinidae of North America of which the generic diversity is greater than previously recognized.

Middle American knob-scaled lizards of the genus Xenosaurus are a unique radiation of viviparous species that are generally characterized by a flattened body shape and a crevice-dwelling ecology. Only eight species of Xenosaurus, one of them with five subspecies (X. grandis), have been formally described. However, species limits within Xenosaurus have never been examined using molecular data, and no complete phylogeny of the genus has been published. Here, we used ddRADseq data from all of the described and potentially undescribed taxa of Xenosaurus to investigate species limits, and to obtain a phylogenetic hypothesis for the genus. We analyzed the data using a variety of phylogenetic models, and were able to reconstruct a well-resolved and generally well-supported phylogeny for this group. We found Xenosaurus to be composed of four major, allopatric clades concordant with geography. The first and second clades that branch off the tree are distributed on the Atlantic slopes of the Sierra Madre Oriental and are composed of X. mendozai, X. platyceps, and X. newmanorum, and X. tzacualtipantecus and an undescribed species from Puebla, respectively. The third clade is distributed from the Atlantic slopes of the Mexican Transvolcanic Belt in west-central Veracruz south to the Pacific slopes of the Sierra Madre del Sur in Guerrero and Oaxaca, and is composed of X. g. grandis, X. rectocollaris, X. phalaroanthereon, X. g. agrenon, X. penai, and four undescribed species from Oaxaca. The last clade is composed of the four taxa that are geographically closest to the Isthmus of Tehuantepec (X. g. arboreus, X. g. rackhami, X. g. sanmartinensis, and an undescribed species from Oaxaca). We also utilized a variety of molecular species delimitation approaches, including analyses with GMYC, PTP, BPP, and BFD ∗ , which suggested that species diversity in Xenosaurus is at least 30% higher than currently estimated., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Bees and flies are the main pollinators responsible for the maintenance of plant diversity and crop production. Studies of pollinator communities have focused on bees; however, community structures may vary among groups of pollinators. We describe and compare the diversity and resource use patterns of six Apoidea and two Diptera anthophile families in Cuatro Ciénegas in the northeast of Mexico. We sampled insects in two distinct geographic units (valley and mountains) and two seasons (rainy and dry). Spatial and temporal patterns in species composition and abundance of these families were identified and the diversity in each family compared. The spatial and temporal patterns in species composition, diversity, and resource use were different for each family. Overall, diversity was higher during the rainy season. Only fly families and the Andrenidae presented season-specific differences in species composition, in contrast with the other Apoidea. Two bee families visited more plant species per insect species during the rainy season, whereas flies visited the same number of plant species in both seasons. Apidae, Megachilidae, and Bombyliidae visited more plant species in the mountains, while the other families exhibited no differences between the mountains and the valley. The variation in the community structures of each group may reflect distinct life histories, resources needs during larval stages, and foraging behaviors. These differences are relevant in management and conservation programs that could benefit one group of pollinators while harming others with different characteristics. The traits of some families indicate their potential value as pollinators., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Forty one new records of species of Bombyliidae are reported for Coahuila in northeastern Mexico. Nine of these species are reported for the first time for the country. The specimens were collected in the Cuatro Ciénegas Basin and Sierra La Madera mountains during 2007-2013. The modified distributions of species are discussed. The gaps in the distribution of many species suggest an undersampling of this group of insects in the north of Mexico.

The widespread montane Mexican horned lizard Phrynosoma orbiculare (Squamata: Phrynosomatidae) represents an ideal species to investigate the relative impacts of Neogene vicariance and Quaternary climate change on lineage diversification across the Mexican highlands. We used mitochondrial DNA to examine the maternal history of P. orbiculare and estimate the timing and tempo of lineage diversification. Based on our results, we inferred 11 geographically structured, well supported mitochondrial lineages within this species, suggesting P. orbiculare represents a species complex. Six divergences between lineages likely occurred during the Late Miocene and Pliocene, and four splits probably happened during the Pleistocene. Diversification rate appeared relatively constant through time. Spatial and temporal divergences between lineages of P. orbiculare and co-distributed taxa suggest that a distinct period of uplifting of the Transvolcanic Belt around 7.5-3 million years ago broadly impacted diversification in taxa associated with this mountain range. To the north, several river drainages acting as filter barriers differentially subdivided co-distributed highland taxa through time. Diversification patterns observed in P. orbiculare provide additional insight into the mechanisms that impacted differentiation of highland taxa across the complex Mexican highlands., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Neogene vicariance during the Miocene and Pliocene and Quaternary climate change have synergistically driven diversification in Mexican highland taxa. We investigated the impacts of these processes on genetic diversification in the widely distributed bunchgrass lizards in the Sceloporus scalaris group. We searched for correlations between timing in diversification and timing of (1) a period of marked volcanism across the Trans-Mexican Volcanic Belt in central Mexico 3-7.5million years ago (Ma) and (2) a transition to larger glacial-interglacial cycles during the mid-Pleistocene. From our phylogenetic analyses of mitochondrial DNA we identified two major clades that contained 13 strongly supported lineages. One clade contained lineages from the two northern sierras of Mexico, and the other clade included lineages associated with the Trans-Mexican Volcanic Belt and Central Mexican Plateau. Results provided support for Neogene divergences within the S. scalaris group in response to uplift of the Trans-Mexican Volcanic Belt, a pattern observed in several co-distributed taxa, and suggested that Quaternary climate change likely had little effect on diversification between lineages. Uplift of the Trans-Mexican Volcanic Belt during specific time periods appears to have strongly impacted diversification in Mexican highland taxa., (Copyright © 2011 Elsevier Inc. All rights reserved.)