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12,309 results for “America”
Data from: New DNA data from a Transthyretin nuclear intron suggest an Oligocene to Miocene diversification of living South America opossums (Marsupialia: Didelphidae).
Phylogenetic relationships of 19 species of didelphid marsupials were studied using two nuclear markers, the non-coding transthyretin intron 1 (TTR) and the coding interphotoreceptor retinoid binding protein exon 1 (IRBP), and two mitochondrial genes, the protein-coding cytochrome b (cyt-b) and the structural 12S ribosomal DNA (12S rDNA). Evolutionary dynamics of these four markers were compared to each other, revealing the appropriate properties presented by TTR intron 1 together with its well supported and resolved phylogenetic signal. Nuclear markers supported the monophyly of medium and large-sized opossums Metachirus+(Chironectes, Lutreolina, Didelphis, Philander), and the paraphyly of mouse-sized opossums, with the genera Gracilinanus, Thylamys, and Marmosops as a sister group to medium and large-sized didelphids. Conflicting branching patterns between mitochondrial and nuclear data involved the phylogenetic position of Marmosa-Micoureus-Monodelphis relative to other mouse-sized opossums. Nuclear phylogenetic inferences among genera were confirmed by the presence of synapomorphic indels observed in TTR intron 1. A Bayesian relaxed molecular clock dating of didelphid evolution using nuclear markers estimated their origin in the Middle Eocene (39.8 million years ago), with subsequent diversification during the Oligocene (Deseadan) and Miocene.
Data from: Earthworm invasion, white-tailed deer and seedling establishment in deciduous forests of northeastern North America
1. Earthworm invasions and high deer populations are among many stressors threatening long-term population viability of forest understorey plants in northeastern North America. Stressor effects are typically tested one at a time, however, stressors often co-occur, and plants respond to effects of multiple stressors simultaneously. 2. We used a factorial design to test independent and combined effects of non-native earthworms and native white-tailed deer on survival of seedling transplants of 15 native understorey plants in 5 forests in New York State. 3. Earthworm biomass was negatively correlated with survival of 12 of 15 species. We found no interactive effect of deer and earthworms, but did find a positive, non-consumptive effect of deer on Geranium maculatum and P. virginianum survival. 4. Deer and earthworm presence/absence indirectly influenced other trophic levels: earthworm presence increased the likelihood of insect attack, and deer exclusion increased the likelihood of rodent attack disturbance of transplants. 5. Synthesis: Invasive earthworms negatively affected seedling survival of many understorey plants, including species previously thought to benefit from earthworm associations. This effect was a function of earthworm biomass, a surrogate for earthworm activity. We expect deer herbivory to increase in importance, including indirect effects, as seedlings grow into browse height over the next years. Investigations of co-occurring stressors can result in 'ecological surprises' including previously overlooked non-consumptive effects or effects on other trophic levels.
Data from: Porcine colonization of the Americas: a 60k SNP story
The pig, Sus scrofa, is a foreign species to the American continent. Although pigs originally introduced in the Americas should be related to those from the Iberian Peninsula and Canary islands, the phylogeny of current creole pigs that now populate the continent is likely to be very complex. Because of the extreme climates that America harbours, these populations also provide a unique example of a fast evolutionary phenomenon of adaptation. Here, we provide a genome wide study of these issues by genotyping, with a 60k SNP chip, 206 village pigs sampled across 14 countries and 183 pigs from outgroup breeds that are potential founders of the American populations, including wild boar, Iberian, international and Chinese breeds. Results show that American village pigs are primarily of European ancestry, although the observed genetic landscape is that of a complex conglomerate. There was no correlation between genetic and geographical distances, neither continent wide nor when analysing specific areas. Most populations showed a clear admixed structure where the Iberian pig was not necessarily the main component, illustrating how international breeds, but also Chinese pigs, have contributed to extant genetic composition of American village pigs. We also observe that many genes related to the cardiovascular system show an increased differentiation between altiplano and genetically related pigs living near sea level.
Data from: Arrival and diversification of caviomorph rodents and platyrrhine primates in South America.
Platyrrhine primates and caviomorph rodents are clades of mammals that colonized South America during its period of isolation from the other continents, between 100 and 3 million years ago (Mya). Until now, no molecular study investigated the timing of the South American colonization by these two lineages with the same molecular data set. Using sequences from three nuclear genes (ADRA2B, vWF, and IRBP, both separate and combined) from 60 species, and eight fossil calibration constraints, we estimated the times of origin and diversification of platyrrhines and caviomorphs via a Bayesian relaxed molecular clock approach. To account for the possible effect of an accelerated rate of evolution of the IRBP gene along the branch leading to the anthropoids, we performed the datings with and without IRBP (3768 sites and 2469 sites, respectively). The time window for the colonization of South America by primates and by rodents is demarcated by the dates of origin (upper bound) and radiation (lower bound) of platyrrhines and caviomorphs. According to this approach, platyrrhine primates colonized South America between 37.0 +/- 3.0 Mya (or 38.9 +/- 4.0 Mya without IRBP) and 16.8 +/- 2.3 (or 20.1 +/- 3.3) Mya, and caviomorph rodents between 45.4 +/- 4.1 (or 43.7 +/- 4.8) Mya and 36.7 +/- 3.7 (or 35.8 +/- 4.3) Mya. Considering both the fossil record and these molecular datings, the favored scenarios are a trans-Atlantic migration of primates from Africa at the end of the Eocene or beginning of the Oligocene, and a colonization of South America by rodents during the Middle or Late Eocene. Based on our nuclear DNA data, we cannot rule out the possibility of a concomitant arrival of primates and rodents in South America. The caviomorphs radiated soon after their arrival, before the Oligocene glaciations, and these early caviomorph lineages persisted until the present. By contrast, few platyrrhine fossils are known in the Oligocene, and the present-day taxa are the result of a quite recent, Early Miocene diversification.
FIGURE 2 in The phylogenetic position of Gallinuloides Eastman (Aves: Galliformes) from the Tertiary of North America
FIGURE 2. Tree resulting from parsimony analysis of the data set for Galliformes presented by Dyke et al. (2003). Character numbers relevant to the placement of Gallinuloides are listed in the text and correspond with those presented in Table 1. Removal of Gallinuloides from 'Phasianidae' to a position consistent with older morphological interpretations of this bird requires examination of trees of at least five additional steps in length.
FIGURE 1 in The phylogenetic position of Gallinuloides Eastman (Aves: Galliformes) from the Tertiary of North America
FIGURE 1. The holotype and only currently described specimen of Gallinuloides wyomingensis Eastman held in the Museum of Comparative Zoology, Harvard University (MCZ), number 2221. Scale bar is 10 mm.
FIGURES 5–8 in A new polydesmid milliped genus and two new species from Oregon and Washington, U. S. A., with a review of Bidentogon Buckett and Gardner, 1968, and a summary of the family in Western North America (Polydesmida: Polydesmidae)
FIGURES 5–8. Retrorsia benedictae (all drawn at 400x magnification) 5, telopodite of left gonopod of holotype, medial view. 6, the same, lateral view. 7, telopodite of left gonopod of male from Pacific County, Washington, medial view. 8, the same, lateral view. F, tibiotarsal flange; other abbreviations as in figs. 3–4.
FIGURE 2 in A new polydesmid milliped genus and two new species from Oregon and Washington, U. S. A., with a review of Bidentogon Buckett and Gardner, 1968, and a summary of the family in Western North America (Polydesmida: Polydesmidae)
FIGURE 2. Distribution of Retrorsia; dots, R. leonardi; triangles, R. benedictae. OR, Oregon; WA, Washington.
FIGURES 3–4. Retrorsia leonardi. 3 in A new polydesmid milliped genus and two new species from Oregon and Washington, U. S. A., with a review of Bidentogon Buckett and Gardner, 1968, and a summary of the family in Western North America (Polydesmida: Polydesmidae)
FIGURES 3–4. Retrorsia leonardi. 3, right gonopod of holotype, medial view (drawn at 200x magnification). 4, telopodite of the same, lateral view (drawn at 400x magnification). C, coxa; E, endomerite; P, pulvillus; PF, prefemur; T, telopodite; TT, tibiotarsus.
FIGURE 1 in A new polydesmid milliped genus and two new species from Oregon and Washington, U. S. A., with a review of Bidentogon Buckett and Gardner, 1968, and a summary of the family in Western North America (Polydesmida: Polydesmidae)
FIGURE 1. Occurrence of the Polydesmidae in western North America; 1, Scytonotus; 2, Calianotus; 3, Utadesmus; 4, Speodesmus; 5, Bidentogon; 6, Retrorsia.
Data from: Genomic patterns of diversity and divergence of two introduced salmonid species in Patagonia, South America
Invasive species have become widespread in aquatic environments throughout the world, yet there are few studies that have examined genomic variation of multiple introduced species in newly colonized environments. In this study, we contrast genomic variation in two salmonid species (anadromous Chinook Salmon, Oncorhynchus tshawytscha, 11,579 SNPs and resident Brook Charr Salvelinus fontinalis, 13,522 SNPs) with differing invasion success after introduction to new environments in South America relative to populations from their native range in North America. Estimates of genetic diversity were not significantly different between introduced and source populations for either species, indicative of propagule pressure that has been shown to maintain diversity in founding populations relative to their native range. Introduced populations also demonstrated higher connectivity and gene flow than those in their native range. Evidence for candidate loci under divergent selection was observed, but was limited to specific introduced populations and was not widely evident. Patterns of genomic variation were consistent with general dispersal potential of each species and therefore also the notion that life history variation may contribute to both invasion success and subsequent genetic structure of these two salmonids in Patagonia.
Data from: Human-mediated disturbance in multitrophic interactions results in outbreak levels of North America's most venomous caterpillar
Abstract Anthropogenic environmental change is predicted to disrupt multitrophic interactions, which may have drastic consequences for population-level processes. Here, we investigate how a large-scale human-mediated disturbance affects the abundance of North America's most venomous caterpillar species, Megalopyge opercularis. Specifically, we used a natural experiment where netting was deployed to cover the entire canopies of a subset of mature southern live oak trees (Quercus virginiana) to exclude urban pest birds (grackles and pigeons), throughout an 8.1-km2 area encompassing a medical center in Houston, Texas. We used this experimental exclusion to test the following hypothesis: release from avian predators increases caterpillar abundance to outbreak levels, which increases the risk to human health. Results from a multi-year survey show that caterpillar abundance increased, on average, >7300% on netted versus non-netted trees. Thus, increases in caterpillar abundance, due to anthropogenic enemy release, increase human exposure to this venomous pest, and should be considered a health threat in the area. This study emphasizes the unforeseen consequences of ecological disturbance for species interactions and highlights the importance of considering ecology in urban planning.
FIGURE 2 in A new genus and six new species of the tropical Camptotypus genusgroup (Hymenoptera: Ichneumonidae; Pimplinae) from northern South America
FIGURE 2. Amazopimpla errabunda Sääksjärvi, Gauld & Jussila, sp.n. Mesosoma, anterior part of metasoma and hind leg, showing colour pattern (Holotype female).
FIGURE 6 in A new genus and six new species of the tropical Camptotypus genusgroup (Hymenoptera: Ichneumonidae; Pimplinae) from northern South America
FIGURE 6. Amazopimpla errabunda Sääksjärvi, Gauld & Jussila, sp.n. The tip of the ovipositor (Holotype female).
FIGURE 9 in A new genus and six new species of the tropical Camptotypus genusgroup (Hymenoptera: Ichneumonidae; Pimplinae) from northern South America
FIGURE 9. Amazopimpla lutea Palacio, Sääksjärvi, Gauld & Jussila, sp.n. The tip of the ovipositor (Paratype female).
FIGURE 8 in A new genus and six new species of the tropical Camptotypus genusgroup (Hymenoptera: Ichneumonidae; Pimplinae) from northern South America
FIGURE 8. Amazopimpla guayanaensis Sääksjärvi, Gauld & Jussila, sp.n. The tip of the ovipositor (Holotype female).
FIGURE 3 in A new genus and six new species of the tropical Camptotypus genusgroup (Hymenoptera: Ichneumonidae; Pimplinae) from northern South America
FIGURE 3. Amazopimpla farallonensis Palacio, sp.n. Mesosoma, anterior part of metasoma and hind leg, showing colour pattern (Holotype female).
FIGURES 5964 in A revision of Nearctic species of the genus Tropimenelytron Pace, 1983 (Coleoptera: Staphylinidae: Aleocharinae), a new genus for North America
FIGURES 5964. Genitalia of Tropimenelytron californicum Gusarov, sp. n. (paratypes from Mineral, California). 59 – spermatheca; 60 – median lobe of aedeagus, parameral view; 61 – median lobe of aedeagus, lateral view; 62 – apex of median lobe, parameral view; 63 – apex of median lobe, lateral view; 64 – apical lobe of left paramere, side facing median lobe. Scale bar 0.1 mm (59, 6264), 0.2 mm (6061).
FIGURES 5558 in A revision of Nearctic species of the genus Tropimenelytron Pace, 1983 (Coleoptera: Staphylinidae: Aleocharinae), a new genus for North America
FIGURES 5558. Details of abdominal segment 8 of Tropimenelytron californicum Gusarov, sp. n. (paratypes from Mineral, California). 55 – male tergum 8; 56 – male sternum 8; 57 – female tergum 8; 58 – female sternum 8. Scale bar 0.5 mm.
FIGURES 4548 in A revision of Nearctic species of the genus Tropimenelytron Pace, 1983 (Coleoptera: Staphylinidae: Aleocharinae), a new genus for North America
FIGURES 4548. Details of abdominal segment 8 of Tropimenelytron robustum Gusarov, sp. n. (holotype (4546), paratype from Hope, British Columbia (4748)). 45 – male tergum 8; 46 – male sternum 8; 47 – female tergum 8; 48 – female sternum 8. Scale bar 0.5 mm.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.