Extreme High-Elevation Mammal Surveys Reveal Unexpectedly High Upper Range Limits of Andean Mice.

AbstractIn the world's highest mountain ranges, uncertainty about the upper elevational range limits of alpine animals represents a critical knowledge gap regarding the environmental limits of life and presents a problem for detecting range shifts in response to climate change. Here we report results of mountaineering mammal surveys in the Central Andes, which led to the discovery of multiple species of mice living at extreme elevations that far surpass previously assumed range limits for mammals. We livetrapped small mammals from ecologically diverse sites spanning >6,700 m of vertical relief, from the desert coast of northern Chile to the summits of the highest volcanoes in the Andes. We used molecular sequence data and whole-genome sequence data to confirm the identities of species that represent new elevational records and to test hypotheses regarding species limits. These discoveries contribute to a new appreciation of the environmental limits of vertebrate life.

A new species of Escallonia (Escalloniaceae) from the inter-Andean tropical dry forests of Bolivia.

Over the last two decades, renewed fieldwork in poorly explored areas of the tropical Andes has dramatically increased the comparative material available to study patterns of inter- and intraspecific variation in tropical plants. In the course of a comprehensive study of the genus Escallonia, we found a group of specimens with decumbent branching, small narrowly elliptic leaves, inflorescences with up to three flowers, and flowers with red petals. This unique combination of traits was not present in any known species of the genus. To evaluate the hypothesis that these specimens belonged to a new species, we assessed whether morphological variation between the putative new species and all currently known Escallonia species was discontinuous. The lack of overlap in tolerance regions for vegetative and reproductive traits combined with differences in habit, habitat, and geographic distribution supported the hypothesis of the new species, which we named Escallonia harrisii. The new species grows in sandstone inter-Andean ridges and cliffs covered with dry forest, mostly on steep slopes between 1,300-2,200 m in southern Bolivia. It is readily distinct in overall leaf and flower morphology from other Escallonia species in the region, even though it does not grow in sympatry with other species. Because E. harrisii is locally common it may not be threated at present, but due to its restricted geographic distribution and the multiple threats of the tropical dry forests it could become potentially vulnerable.

Taxonomic status of Rhabdochona ictaluri (Nematoda: Rhabdochonidae) based on molecular and morphological evidence.

The genus Rhabdochona includes more than 100 species infecting freshwater fishes in all zoogeographical regions of the world. In Mexico, 12 nominal species of Rhabdochona have been recorded. Of these, Rhabdochona ictaluri was originally described as a parasite of endemic catfishes of the family Ictaluridae; however, the species was later considered on morphological grounds as a junior synonym of Rhabdochona kidderi. In this study, newly sampled specimens of R. ictaluri were obtained from the type host and type locality and were used to perform a detailed morphological analysis and molecular phylogenetic inferences through one mitochondrial and two nuclear genes; data were used in an integrative taxonomy context to test the taxonomic status of R. ictaluri. This approach proved to be very useful to confirm the validity of this species, and robust species limits were established between these two putative species considering morphology, molecular data, host association, and biogeography.

Combining ultraconserved elements and mtDNA data to uncover lineage diversity in a Mexican highland frog (Sarcohyla; Hylidae).

Molecular studies have uncovered significant diversity in the Mexican Highlands, leading to the description of many new endemic species. DNA approaches to this kind of species discovery have included both mitochondrial DNA (mtDNA) sequencing and multilocus genomic methods. While these marker types have often been pitted against one another, there are benefits to deploying them together, as linked mtDNA data can provide the bridge between uncovering lineages through rigorous multilocus genomic analysis and identifying lineages through comparison to existing mtDNA databases. Here, we apply one class of multilocus genomic marker, ultraconserved elements (UCEs), and linked mtDNA data to a species complex of frogs (Sarcohyla bistincta, Hylidae) found in the Mexican Highlands. We generated data from 1,891 UCEs, which contained 1,742 informative SNPs for S. bistincta and closely related species and captured mitochondrial genomes for most samples. Genetic analyses based on both whole loci and SNPs agree there are six to seven distinct lineages within what is currently described as S. bistincta. Phylogenies from UCEs and mtDNA mostly agreed in their topologies, and the few differences suggested a more complex evolutionary history of the mtDNA marker. Our study demonstrates that the Mexican Highlands still hold substantial undescribed diversity, making their conservation a particularly urgent goal. The Trans-Mexican Volcanic Range stands out as a significant geographic feature in Sarcohyla and may have acted as a dispersal corridor for S. bistincta to spread to the north. Combining multilocus genomic data with linked mtDNA data is a useful approach for identifying potential new species and associating them with already described taxa, which will be especially important in groups with undescribed subadult phenotypes and cryptic species.

Molecular systematics of swifts of the genus Chaetura (Aves: Apodiformes: Apodidae).

Phylogenetic relationships among swifts of the morphologically conservative genus Chaetura were studied using mitochondrial and nuclear DNA sequences. Taxon sampling included all species and 21 of 30 taxa (species and subspecies) within Chaetura. Our results indicate that Chaetura is monophyletic and support the division of the genus into the two subgenera previously identified using plumage characters. However, our genetic data, when considered in combination with phenotypic data, appear to be at odds with the current classification of some species of Chaetura. We recommend that C. viridipennis, currently generally treated as specifically distinct from C. chapmani, be returned to its former status as C. chapmani viridipennis, and that C. andrei, now generally regarded as synonymous with C. vauxi aphanes, again be recognized as a valid species. Widespread Neotropical species C. spinicaudus is paraphyletic with respect to more range-restricted species C. fumosa, C. egregia, and C. martinica. Geographically structured genetic variation within some other species of Chaetura, especially notable in C. cinereiventris, suggests that future study may lead to recognition of additional species in this genus. Biogeographic analysis indicated that Chaetura originated in South America and identified several dispersal events to Middle and North America following the formation of the Isthmus of Panama.

Revision of the species of Lytopylus from Area de Conservación Guanacaste, northwestern Costa Rica (Hymenoptera, Braconidae, Agathidinae).

Thirty two new species of Lytopylus (Agathidinae) are described with image plates for each species: Lytopylus alejandromasisisp. n., Lytopylus alfredomainierisp. n., Lytopylus anamariamongeaesp. n., Lytopylus angelagonzalezaesp. n., Lytopylus cesarmoraisp. n., Lytopylus eddysanchezisp. n., Lytopylus eliethcantillanoaesp. n., Lytopylus ericchapmanisp. n., Lytopylus gahyunaesp. n., Lytopylus gisukaesp. n., Lytopylus guillermopereiraisp. n., Lytopylus gustavoinduniisp. n., Lytopylus hartmanguidoisp. n., Lytopylus hernanbravoisp. n., Lytopylus hokwonisp. n., Lytopylus ivanniasandovalaesp. n., Lytopylus johanvalerioisp. n., Lytopylus josecortesisp. n., Lytopylus luisgaritaisp. n., Lytopylus mariamartachavarriaesp. n., Lytopylus miguelviquezisp. n., Lytopylus motohasegawaisp. n., Lytopylus okchunaesp. n., Lytopylus pablocobbisp. n., Lytopylus robertofernandezisp. n., Lytopylus rogerblancoisp. n., Lytopylus salvadorlopezisp. n., Lytopylus sangyeonisp. n., Lytopylus sarahmeierottoaesp. n., Lytopylus sergiobermudezisp. n., Lytopylus sigifredomarinisp. n., and Lytopylus youngcheaesp. n. A dichotomous key and a link to an electronic, interactive key are included. All specimens were reared from Lepidoptera larvae collected in Area de Conservación Guanacaste (ACG) and all are associated with ecological information including host caterpillar, collection date, eclosion date, caterpillar food plant, and locality. Neighbor-joining and maximum likelihood analyses of the barcode region of the mitochondrial cytochrome c oxidase subunit I gene (COI DNA barcode) were conducted to aid in species delimitation.

Montane and coastal species diversification in the economically important Mexican grasshopper genus Sphenarium (Orthoptera: Pyrgomorphidae).

The genus Sphenarium (Pyrgomorphidae) is a small group of grasshoppers endemic to México and Guatemala that are economically and culturally important both as a food source and as agricultural pests. However, its taxonomy has been largely neglected mainly due to its conserved interspecific external morphology and the considerable intraspecific variation in colour pattern of some taxa. Here we examined morphological as well as mitochondrial and nuclear DNA sequence data to assess the species boundaries and evolutionary history in Sphenarium. Our morphological identification and DNA sequence-based species delimitation, carried out with three different approaches (DNA barcoding, general mixed Yule-coalescent model, Bayesian species delimitation), all recovered a higher number of putative species of Sphenarium than previously recognised. We unambiguously delimit seven species, and between five and ten additional species depending on the data/method analysed. Phylogenetic relationships within the genus strongly support two main clades, one exclusively montane, the other coastal. Divergence time estimates suggest late Miocene to Pliocene ages for the origin and most of the early diversification events in the genus, which were probably influenced by the formation of the Trans-Mexican Volcanic Belt. A series of Pleistocene events could have led to the current species diversification in both montane and coastal regions. This study not only reveals an overlooked species richness for the most popular edible insect in Mexico, but also highlights the influence of the dynamic geological and climatic history of the region in shaping its current diversity.

Evolutionary diversification and speciation in rodents of the Mexican lowlands: the Peromyscus melanophrys species group.

Despite some studies of the species groups within the genus Peromyscus have been performed, both evolutionary relationships among species within groups and group composition have remained controversial. In this study, we address phylogenetic relationships among species in the Peromyscus melanophrys group (P. melanophrys, P. perfulvus, and P. mekisturus), using a molecular phylogenetic analysis. This analysis is the first to include the poorly known P. mekisturus. We conducted maximum likelihood and Bayesian inference analyses with the ND3, tRNA-Arginine, ND4L, and partial ND4 mitochondrial genes, and the GHR nuclear gene. We consistently recovered a P. melanophrys group that is monophyletic with respect to the set of outgroups. Also, we recovered two distinct clades within P. perfulvus and two within P. melanophrys, one of which contain P. mekisturus among other P. melanophrys, all with geographic consistency. According to our divergence time estimates, the P. melanophrys group diverged during the Pliocene and the main diversification events within the group occurred at the end of the Pliocene and through the Pleistocene.

Taxonomy and biogeography of Stephanoxis Simon, 1897 (Aves: Trochilidae)

After the description in the 19th century of two hummingbird species currently allocated to the genus Stephanoxis, Peters (1945) merged both taxa into a single species without providing any rationale. Here we re-evaluate the taxonomy and species limits of the representatives of this genus based on an extensive number of specimens. We demonstrate these taxa are better treated as full species under both the Biological and Phylogenetic Species Concepts due to their well-defined range and plumage patterns and reciprocally diagnosability. They have distinct, allopatric distributions segregated by a 160 km gap between the Serra do Mar, to the east, and Serra de Paranapiacaba, to the west, in the state of São Paulo. Stephanoxis species have ranges which are congruent with other montane bird species suggesting shared vicariance events during preterit interglacial periods.(AU)

Taxonomy and biogeography of Stephanoxis Simon, 1897 (Aves: Trochilidae)

After the description in the 19th century of two hummingbird species currently allocated to the genus Stephanoxis, Peters (1945) merged both taxa into a single species without providing any rationale. Here we re-evaluate the taxonomy and species limits of the representatives of this genus based on an extensive number of specimens. We demonstrate these taxa are better treated as full species under both the Biological and Phylogenetic Species Concepts due to their well-defined range and plumage patterns and reciprocally diagnosability. They have distinct, allopatric distributions segregated by a 160 km gap between the Serra do Mar, to the east, and Serra de Paranapiacaba, to the west, in the state of São Paulo. Stephanoxis species have ranges which are congruent with other montane bird species’ suggesting shared vicariance events during preterit interglacial periods.

Scapteromys aquaticus (Rodentia: Sigmodontinae) in Brazil with comments on karyotype and phylogenetics relationships

The swamp rats are distributed in Argentina, southern Paraguay, Uruguay and southern Brazil, with two species currently accepted: Scapteromys aquaticus Thomas, 1920 and Scapteromys tumidus Waterhouse, 1837. While S. aquaticus occurs in Argentina, Paraguay and western Uruguay, S. tumidus occurs in Brazil and Uruguay. Here we report for the first time the occurrence of S. aquaticus in gallery forest remnants in Southern Brazil. Karyologic analysis showed 2n = 32 and FNa = 40. Phylogenetic analyses, based on DNA sequences from the mitochondrial cytochrome-b gene indicate that the Brazilian and the Argentinian specimens of S. aquaticus shared one haplotype, while median joining analysis showed lack of population structure. This register, plus the karyotype data available for Brazilian population, recovered four karyomorphotypes in Brazil, corresponding to the two known species of Scapteromys and two unnamed species. This scenario indicates that more multidisciplinary studies are necessary to understand the actual diversity of Scapteromys.

Scapteromys aquaticus (Rodentia: Sigmodontinae) in Brazil with comments on karyotype and phylogenetics relationships

The swamp rats are distributed in Argentina, southern Paraguay, Uruguay and southern Brazil, with two species currently accepted: Scapteromys aquaticus Thomas, 1920 and Scapteromys tumidus Waterhouse, 1837. While S. aquaticus occurs in Argentina, Paraguay and western Uruguay, S. tumidus occurs in Brazil and Uruguay. Here we report for the first time the occurrence of S. aquaticus in gallery forest remnants in Southern Brazil. Karyologic analysis showed 2n = 32 and FNa = 40. Phylogenetic analyses, based on DNA sequences from the mitochondrial cytochrome-b gene indicate that the Brazilian and the Argentinian specimens of S. aquaticus shared one haplotype, while median joining analysis showed lack of population structure. This register, plus the karyotype data available for Brazilian population, recovered four karyomorphotypes in Brazil, corresponding to the two known species of Scapteromys and two unnamed species. This scenario indicates that more multidisciplinary studies are necessary to understand the actual diversity of Scapteromys.

Scapteromys aquaticus (Rodentia: Sigmodontinae) in Brazil with comments on karyotype and phylogenetics relationships

The swamp rats are distributed in Argentina, southern Paraguay, Uruguay and southern Brazil, with two species currently accepted: Scapteromys aquaticus Thomas, 1920 and Scapteromys tumidus Waterhouse, 1837. While S. aquaticus occurs in Argentina, Paraguay and western Uruguay, S. tumidus occurs in Brazil and Uruguay. Here we report for the first time the occurrence of S. aquaticus in gallery forest remnants in Southern Brazil. Karyologic analysis showed 2n = 32 and FNa = 40. Phylogenetic analyses, based on DNA sequences from the mitochondrial cytochrome-b gene indicate that the Brazilian and the Argentinian specimens of S. aquaticus shared one haplotype, while median joining analysis showed lack of population structure. This register, plus the karyotype data available for Brazilian population, recovered four karyomorphotypes in Brazil, corresponding to the two known species of Scapteromys and two unnamed species. This scenario indicates that more multidisciplinary studies are necessary to understand the actual diversity of Scapteromys.(AU)