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1. Insights from a comprehensive study of Trypanosoma cruzi: A new mitochondrial clade restricted to North and Central America and genetic structure of TcI in the region

   https://doi.org/10.1371/journal.pntd.0010043  

   Lima-Cordón, Raquel Asunción; Cahan, Sara Helms; McCann, Cai; Dorn, Patricia L.; Justi, Silvia Andrade; Rodas, Antonieta; Monroy, María Carlota; Stevens, Lori (December 2021, PLOS Neglected Tropical Diseases)

   Dutra, Walderez O. (Ed.)

   More than 100 years since the first description of Chagas Disease and with over 29,000 new cases annually due to vector transmission (in 2010), American Trypanosomiasis remains a Neglected Tropical Disease (NTD). This study presents the most comprehensive Trypanosoma cruzi sampling in terms of geographic locations and triatomine species analyzed to date and includes both nuclear and mitochondrial genomes. This addresses the gap of information from North and Central America. We incorporate new and previously published DNA sequence data from two mitochondrial genes, Cytochrome oxidase II (COII) and NADH dehydrogenase subunit 1 (ND1). These T . cruzi samples were collected over a broad geographic range including 111 parasite DNA samples extracted from triatomines newly collected across North and Central America, all of which were infected with T . cruzi in their natural environment. In addition, we present parasite reduced representation (Restriction site Associated DNA markers, RAD-tag) genomic nuclear data combined with the mitochondrial gene sequences for a subset of the triatomines (27 specimens) collected from Guatemala and El Salvador. Our mitochondrial phylogenetic reconstruction revealed two of the major mitochondrial lineages circulating across North and Central America, as well as the first ever mitochondrial data for TcBat from a triatomine collected in Central America. Our data also show that within mtTcIII, North and Central America represent an independent, distinct clade from South America, named here as mtTcIII NA-CA , geographically restricted to North and Central America. Lastly, the most frequent lineage detected across North and Central America, mtTcI, was also an independent, distinct clade from South America, noted as mtTcI NA-CA . Furthermore, nuclear genome data based on Single Nucleotide Polymorphism (SNP) showed genetic structure of lineage TcI from specimens collected in Guatemala and El Salvador supporting the hypothesis that genetic diversity at a local scale has a geographical component. Our multiscale analysis contributes to the understanding of the independent and distinct evolution of T . cruzi lineages in North and Central America regions. 

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2. Consumer roles of small mammals within fragmented native tallgrass prairie

   https://doi.org/10.1002/ecs2.3441  

   Hope, Andrew_G; Gragg, Sabrina_F; Nippert, Jesse_B; Combe, Fraser_J (March 2021, Ecosphere)

   Abstract Grassland ecosystems globally are being negatively impacted by changes in climate, disturbance regimes, nutrient flux, and consumer guilds. Changes in the trophic ecology of consumers can substantially influence local resources, contributing to shifting diversity, community turnover, and other processes of ecosystem change. Small mammals are diverse and abundant within grasslands and yet the impact of changing ecosystems on small mammals and the role of these mammals as consumers are still both under‐studied. We assessed small mammal resource use within grassland and woodland vegetation types that have resulted from landscape‐scale experimental disturbance through fire treatments within the tallgrass prairie ecoregion of the North American Great Plains. We predicted that resource use would vary significantly among grassland vs. woodland communities, in turn reducing the role of small mammals in contributing to future maintenance of native prairies. We sampled five dominant species of rodents across three years and multiple habitats. Using stable isotope analysis, we investigated isotopic niche area and overlap to infer variation in diet, both within and among species. Resource use shifted in bivariate isotopic space seasonally but not across years when combining all species and habitats. Inferred spring diet (based on fur samples) was highly diverse and overlapping. Summer isotopic values (based on liver tissue) in woody habitat treatments were narrower and overlapped less than within grassland habitats. Consumers generally shifted from C₄herbivory to C₃herbivory, or greater omnivory, when analyzing grassland, shrubland, and woodland habitats respectively. Within the tallgrass prairie ecosystem, small mammal populations in herbaceous‐dominated habitats use a broader variety of resources than small mammals in proximate woody‐dominated habitats. As native grasslands experience woody encroachment, small mammal assemblages experience turnover of dominant species and associated changes in diet. Ecosystem changes such as cessation of frequent fire resulting in more woody habitats may include reduced roles by native small mammals as consumers/dispersers/propagators of native grassland plants. 

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3. Citellinema (Nematoda: Heligmosomidae) from North America with descriptions of 2 new species from the red squirrel Tamiasciurus hudsonicus and 1 from the Canadian woodchuck, Marmota monax

   https://doi.org/10.1017/S0031182022000737  

   Alnaqeb, Haitham; Galbreath, Kurt E.; Koehler, Anson V.; Campbell, Mariel L.; Jiménez, F. Agustín (August 2022, Parasitology)

   Abstract Citellinema Hall, 1918 includes 6 valid species of gastrointestinal nematodes of sciurids. Two species occur in the Palearctic and 4 in the Nearctic, 3 of which occur minimally across Colorado, Idaho and Oregon and 1, Citellinema bifurcatum , has a wide distribution across North America. Members of the genus are didelphic, possess a cephalic vesicle, a terminal spine-like process in females and feature robust spicules, consisting of a proximal end fused and semicylindrical shaft connected to a lamina supported by 2 terminal filiform processes. Typically, the size of the spicules is used to differentiate species. As part of the Beringian Coevolution Project, specimens provisionally identified as C. bifurcatum were collected through intensive field sampling of mammals and associated parasites from across localities spanning the Holarctic. These specimens revealed considerable genetic variability at both mitochondrial and nuclear loci, supporting the identification of deeply divergent clades. Examination of these new specimens, along with the holotypes of C. bifurcatum and Citellinema quadrivittati indicates that Citellinema monacis (previously synonymized with C . bifurcatum ) should be resurrected and 3 additional species described. We suggest that the apparent bifurcated nature of the spicule should be considered a generic diagnostic trait, while the proportional length of the lamina relative to that of the spicule is used as a specific character. We demonstrate the critical need for continued inventory of often poorly known assemblages of hosts and parasites, contributing to a growing baseline of archival specimens, collections and information that make explorations of faunal structure and diversity possible. 

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4. Discovery of Aulacidea follioti Barbotin, 1972 (Hymenoptera: Cynipidae: Aulacideini) in the United States and Canada

   Nastasi, Louis F; Deans, Andrew R (September 2024, Journal of the Entomological Society of Ontario)

   Aulacidea follioti Barbotin, 1972 (Hymenoptera: Cynipidae: Aulacideini) is a species of gall wasp inducing stem galls on Sonchus asper (L.) Hill (Asteraceae: Cichorieae). While this species is native to western Europe, we located specimens of this species deposited in several North American collections. The nine specimens we examined suggest that the species is present in several US states and Canadian provinces and has been present in North America since at least 1948. An observation showing the gall and larvae of the species in Oregon (USA) was uploaded to the community science platform iNaturalist in July 2024, confirming that the species is still present in North America. 

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5. One Antarctic slug to confuse them all: the underestimated diversity of Doris kerguelenensis

   https://doi.org/https://doi.org/10.1071/IS21073  

   Maroni, P. J. (June 2022, Invertebrate systematics)

   The Antarctic marine environment, although rich in life, is predicted to experience rapid and significant effects from climate change. Despite a revolution in the approaches used to document biodiversity, less than one percent of Antarctic marine invertebrates are represented by DNA barcodes and we are at risk of losing biodiversity before discovery. The ease of sequencing mitochondrial DNA barcodes has promoted this relatively ‘universal’ species identification system across most metazoan phyla and barcode datasets are currently readily used for exploring questions of species-level taxonomy. Here we present the most well-sampled phylogeny of the direct-developing, Southern Ocean nudibranch mollusc, Doris kerguelenensis to date. This study sampled over 1000 new Doris kerguelenensis specimens spanning the Southern Ocean and sequenced the mitochondrial COI gene. Results of a maximum likelihood phylogeny and multiple subsequent species delimitation analyses identified 27 new species in this complex (now 59 in total). Using rarefaction techniques, we infer more species are yet to be discovered. Some species were only collected from southern South America or the sub-Antarctic islands, while at least four species were found spanning the Polar Front. This is contrary to dispersal predictions for species without a larval stage such as Doris kerguelenensis. Our work demonstrates the value of increasing geographic scope in sampling and highlights what could be lost given the current global biodiversity crisis. 

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