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The tick species that comprise the Amblyomma maculatum group (Acari: Ixodidae) are widely distributed in the Nearctic and Neotropical regions, ranging from the United States of America (USA) to Argentina. This group includes three species: Amblyomma maculatum, Amblyomma tigrinum, and Amblyomma triste, which parasitize a high number of vertebrates, including domestic mammals and humans, where they are the main vectors of Rickettsia parkeri s.s. The identification, distribution, and validity of the three species within the group have been controversial and continue to raise questions. Previous studies have mostly focused on the analysis of partial nuclear and mitochondrial genes, highlighting the need for new integrative analyses that contribute to clarifying their systematics and ecology. In this investigation, we obtained the first mitochondrial genome of A. triste (14,808 bp), which, upon comparison with the reported mitochondrial genomes of A. maculatum, exhibits a genetic distance of 4.2%, providing new evidence for the validity of the former species. The order, composition, and structure of the mitogenome of A. triste are consistent with the characteristics reported for most Metastriata including taxa within Amblyomma, that count with several mitochondrial genomes published in the last few years. The attributes of the mitogenomes, such as the absence of paralogs and a small genome, confirm the utility in studies involving complexes of cryptic species as it also serves as a robust tool for inferring phylogenies. Furthermore, we reported new molecular markers at the mitochondrial level which can be used in phylogenetic studies for other tick species, especially those with controversial or challenging taxonomy. We highlight the need of sequencing the mitochondrial genome of A. tigrinum, which is part of the A. maculatum group, as well as experimental crosses of populations from different places in the Americas to obtain additional evidence for species recognition. [ABSTRACT FROM AUTHOR]

Plesiopelma longisternale is a widespread tarantula in Argentina and its limit is difficult to determine due to their morphological variation among populations. Males are distinguishable by the following character combination: a field of spines on the apical half of the palpal tibia, a very long embolus and a field of spines on the reotrolateral face of cymbium; females are characterized by long spiraled ducts distant from each other. Here, we used mitochondrial DNA (cox1) to reconstruct the first phylogeny of P. longisternale , in combination with morphological data and molecular species delimitation, to assess the taxonomic limits of this species. Our phylogenetic results confirm a close relationship among the populations from central Argentina and a new evolutionary independent lineage identified as a new species, Plesiopelma absconditus , which is here diagnose, described and illustrated. We further analyzed the diagnostic characters of P. longisternale through the examination of the types and specimens from many populations and found that their morphological intraspecific variations largely overlap. Altogether, our results demonstrate that some of the variability of P. longisternale in central Argentina represent polymorphisms of a single species supported by molecular data. In addition, we discovered a new species from this genus distinguishable by molecular and morphological data and highlight the need for multiple lines of evidence to solve the taxonomic problems in species of tarantulas. [ABSTRACT FROM AUTHOR]

The genus Ctenomys is the most speciose of all known subterranean rodents. Currently, most species of this genus are included in eight distinctive phylogenetic groups. The Ctenomys talarum phylogenetic group has remained invariant in terms of the number of species in recent years. This group of species forms a well-supported monophyletic clade composed of the nominal species Ctenomys talarum (Thomas 1898) and Ctenomys pundti (Nehring 1900), which are distributed in the pampas region, a vast plains extending westward across Central Argentina from the Atlantic coast to the Andean foothills. This phylogenetic group also includes some Pampean populations with an uncertain taxonomic status but geographically close to the distribution of C. pundti. These populations were originally associated with C. pundti and called in conjunction C. pundti complex. Due to the phylogenetic proximity between populations of this complex and C. talarum, the phylogenetic relationships within the C. talarum group are currently under review. Here we use mitochondrial DNA sequences of the non-coding region of D-loop (434 bp) to assess the historical demography and phylogeography of populations belonging to the C. talarum group. This study includes individuals from populations sampled across a wide region (approximately 518,000 km2) in Central Argentina. Analysis of molecular variance (AMOVA) and pairwise ФST estimates between sampling locations showed significant population genetic substructure at local and regional levels. However, phylogeographic genetic subdivision in the C. talarum group is rather weak and does not follow a pattern of isolation by distance. In this way, Bayesian analyses showed a weak signal of demographic expansion followed by a small reduction in the effective population size (Ne), which occurred approximately 2000 years before present (ybp). This reduction in the Ne was probably due to changes in the landscape configuration during the Late Holocene. According to our results and paleontological records, current populations of the C. talarum group are likely remnants of a much broader and more continuous historical distribution in the Pampas region. Finally, phylogenetic analyses (Bayesian and Maximum Likelihood inferences) showed that populations previously assigned to the C. pundti complex should be referred to belonging to C. talarum. [ABSTRACT FROM AUTHOR]

In the Neotropical region, the genetic diversity and bioclimatic preferences of Ephemeroptera are poorly known mainly due to the lack of studies. We used the 16S rRNA mitochondrial gene to examine the genetic structure of Baetodes huaico , an aquatic insect distributed in the Northwest of Argentina. Also, we performed an ecological niche modeling (ENM) to understand bioclimatic preferences and combine with the genetic data to understand historical dynamic distribution of B. huaico. We found that B. huaico populations are genetically structured into two distinct geographic groups. The ENM showed a distributional shift from south to north through time. Also, we recovered a stable region over time in the Southwest of Tucumán with the highest value of suitability and high genetic diversity; this region was previously proposed as a Pleistocene refuge. Our result suggests that the northern group was stable over time and underwent a recent demographic expansion coincident with a glacial refugium, whereas the southern group could have been affected by climatic fluctuations during. The results emphasize possible climatic influences in genetic population differentiation, and contributes to the knowledge of the genetic diversity of Ephemeroptera from subtropical Argentina laying the groundwork for future work for other freshwater insects in our region. [ABSTRACT FROM AUTHOR]

Jatropha curcas (Linnaeus, 1753) is a plant species in the order Malpighiales and the family Euphorbiaceae and is native to the tropical regions of America, such as Mexico and Argentina. Currently, this plant species inhabits tropical and subtropical regions of the world. Jatropha has been widely used as a biofuel plant to produce high-quality diesel engine fuel. In this study, the complete mitochondrial genome sequence of J. curcas was assembled into 561,839 bp circular nucleotides with a GC content of 44.6%. The mitochondrial genome of J. curcas comprises 33 known protein-coding genes, 22 tRNA genes, three rRNA genes, one ncRNA gene, and 85 open reading frame genes. Phylogenetic analysis showed this species is closely related to the castor bean (Ricinus communis). [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study was to enhance our understanding of the population history in South America, specifically Northwestern Argentina, by analyzing complete ancient mitogenomes of individuals from the Ojo de Agua archeological site (970 BP) in Quebrada del Toro (Salta, Argentina). Materials and Methods: We analyzed teeth from four individuals from the site Ojo de Agua (970 ± 60 BP), located in Quebrada del Toro (Andean region of Northwestern Argentina). DNA extracts were converted to double‐stranded DNA libraries and indexed using unique dual‐indexing primer combinations. DNA libraries were then enriched for the complete mitochondrial genome, pooled at equimolar concentrations, and sequenced on an Illumina® MiSeq™ platform. Reads from high quality libraries were trimmed, merged, and then mapped to the revised Cambridge Reference Sequence. The aDNA damage patterns were assessed and contamination estimated. Finally, variants were called, filtered, and the consensus mitogenome was constructed and used for haplogroup assignment. We also compiled available mitogenome sequences from ancient and present‐day populations from the Southcentral Andes and other surrounding regions in Argentina. Maximum Likelihood and Bayesian phylogenetic reconstructions were obtained using the generated dataset. Results: We successfully obtained the complete mitogenome sequence from one individual with an average depth coverage of 102X. We discovered a novel haplotype that was assigned to haplogroup D1. Phylogenetic reconstructions suggests that this haplotype falls within the sister branches of the D1j lineage, forming a well‐supported clade. The estimate TMRCA of this clade that includes D1j and its sister branches ranged between 12,535 and 18,669 ya. Discussion: The sequence analyzed in this study represents the first ancient mitogenome from within the valley region in Northwestern Argentina. We found that a representative of a lineage highly associated with D1j was already present approximately 1000 BP in the region. Our results agree with the proposed origin of D1j in other regions north of Patagonia and independent of the Pacific coast fast migratory route, contrary to what was originally hypothesized. This study highlights the lack of information regarding pre‐Hispanic genetic diversity and contributes to the knowledge about the peopling process in South America. [ABSTRACT FROM AUTHOR]

Ctenomys is one of the most speciose genera among South American rodents, whose systematics have not yet been fully elucidated. One of the difficulties for clarifying the identity of its species is the limited information available on some of them, erected more than a century ago and of which only the original descriptions are known, generally very poorly detailed. Our study provides new information about Ctenomys coludo Thomas 1920, based on the collection of topotype specimens that allowed us to perform more detailed morphological and molecular analyses, and to compare them with the available information referred to the holotype, with specimens deposited in museum collections, and other species of the genus that have been proposed as related to C. coludo. Our results allow us to place C. coludo as a member of the mendocinus group, proposing C. famosus Thomas, 1920 as a junior synonym for C. coludo. We also recognize Ctenomys johannis as a valid and full species, and provide unpublished information on it from the collection of specimens at the type locality. Thus, we add new areas for the distribution of these species and present their phylogenetic relationships. [ABSTRACT FROM AUTHOR]

Objective: This study aims to contribute to the recovery of Indigenous evolutionary history in the Southern Pampas region of Argentina through an analysis of ancient complete mitochondrial genomes. Materials and Methods: We generated DNA data for nine complete mitogenomes from the Southern Pampas, dated to between 2531 and 723 cal BP. In combination with previously published ancient mitogenomes from the region and from throughout South America, we documented instances of extra‐regional lineage‐sharing, and estimated coalescent ages for local lineages using a Bayesian method with tip calibrations in a phylogenetic analysis. Results: We identified a novel mitochondrial haplogroup, B2b16, and two recently defined haplogroups, A2ay and B2ak1, as well as three local haplotypes within founder haplogroups C1b and C1d. We detected lineage‐sharing with ancient and contemporary individuals from Central Argentina, but not with ancient or contemporary samples from North Patagonian or Littoral regions of Argentina, despite archeological evidence of cultural interactions with the latter regions. The estimated coalescent age of these shared lineages is ~10,000 years BP. Discussion: The history of the human populations in the Southern Pampas is temporally deep, exhibiting long‐term continuity of mitogenome lineages. Additionally, the identification of highly localized mtDNA clades accords with a model of relatively rapid initial colonization of South America by Indigenous communities, followed by more local patterns of limited gene flow and genetic drift in various South American regions, including the Pampas. [ABSTRACT FROM AUTHOR]

We report the results of bioarchaeological, genetic, malacological, and lithic analyses of a burial located in the Calamuchita Valley in the province of Córdoba in central Argentina. We discuss these findings from an osteobiographical perspective that considers the physical body from three spheres of analysis: biological, social, and political. The skeletal remains correspond to an adult male who died 3770 ± 90 14C years BP (4404–3850 cal BP). His mitochondrial lineage A2+16192-16248 could have originated in central Argentina; this lineage subsequently became extinct in modern populations. In association with the human bones, there were two lithic tools, ornamental shells, and a stone pendant arranged as a necklace. This type of context is infrequently found in the region and the period studied. Thus, this burial represents a rare and relevant record for regional and South American archaeology, providing the oldest direct evidence of a burial with grave goods in hunter-gatherer societies of the province of Córdoba, central region of Argentina. [ABSTRACT FROM AUTHOR]

The coastal dunes of the southeast of Buenos Aires province, Argentina, present two different described species of tuco-tucos: Ctenomys talarum and C. australis. Formerly, C. talarum was subdivided into three subspecies (C. t. talarum , C. t. recessus , and C. t. occidentalis), mainly based on its geographic distribution and phenotypic variation in characters of external morphology (e.g. body size and pelage color). This study assesses the phylogenetic relationships of C. talarum , focusing on the populations at the western end of its coastal distribution (localities of Pehuen-Có and Sauce Grande), which have been previously identified as highly genetically divergent. In this regard, populations distributed throughout the range of the species were sampled. Complete DNA sequences of the mitochondrial cytochrome b gene (1,140 bp), partial sequences of the mitochondrial D-loop region (426 bp), and partial sequences of the nuclear DNA intron 8 of the β-fibrinogen (about 870 bp) gene were used for the analyses. Phylogenetic inferences based on mitochondrial and nuclear markers were performed separately or combined to obtain a species tree. Populations distributed at the western end of the coastal dunes (between Pehuen-Có and Sauce Grande), previously assumed as C. talarum , were found to belong to an independent lineage relative to the other populations from the Pampas region. The average genetic distance between these two lineages is within the order of the genetic distances observed between different species of the genus. Also, our results show that this lineage of Ctenomys presents a high affinity with the magellanicus group, which is distributed further south, in Patagonia. In conclusion, tuco-tuco populations occurring in the coastal expanse between these two localities should be considered a possible distinct cryptic species, highly differentiated from C. talarum. [ABSTRACT FROM AUTHOR]

The present study investigates the spectrum and analysis of mitochondrial DNA (mtDNA) variants associated with Leber hereditary optic neuropathy (LHON) in an Argentinean cohort, analyzing 3 LHON-associated mitochondrial genes. In 32% of the cases, molecular confirmation of the diagnosis could be established, due to the identification of disease-causing variants. A total of 54 variants were observed in a cohort of 100 patients tested with direct sequencing analysis. The frequent causative mutations m.11778G>A in MT-ND4, m.3460G>A in MT-ND1, and m.14484T>C in MT-ND6 were identified in 28% of the cases of our cohort. Secondary mutations in this Argentinean LHON cohort were m.11253T>C p.Ile165Thr in MT-ND4, identified in three patients (3/100, 3%) and m.3395A>G p.Tyr30Cys in MT-ND1, in one of the patients studied (1%). This study shows, for the first time, the analysis of mtDNA variants in patients with a probable diagnosis of LHON in Argentina. Standard molecular methods are an effective first approach in order to achieve genetic diagnosis of the disease, leaving NGS tests for those patients with negative results. [ABSTRACT FROM AUTHOR]

Clinostomidae is a diverse family of digenean parasitizing fish-eating birds as adults and fishes as metacercariae. The species composition, within the genus Clinostomum has been steadily increasing in recent years. In Argentina, four named species of Clinostomum have been documented, accompanied by four metacercariae representing distinct genetic lineages whose adults have not been identified. This study focused on examining clinostomids in three fish species – Australoheros scitulus (ASI), Cichlasoma dimerus (CDIM), and Pimelodella laticeps (PLA) – at various localities in Argentina. We conducted both morphological and molecular characterizations of the Clinostomum metacercariae collected from these fish species. Molecular phylogenetic analyses using COI mtDNA were performed to determine the placement of these metacercariae within the clinostomid phylogenetic tree. Clinostomum ASC represents a distinct lineage, morphologically distinguishable from other sequenced metacercariae due to its body shape (widest anteriorly and becoming slender towards the posterior end); this lineage was found to be closely related to C. caffarae. While Clinostomum CDIM and Clinostomum PLA exhibited morphological differences, they clustered together genetically with metacercariae reported in previous studies as Clinostomum L3 and Clinostomum CVI. This outcome, coupled with a low genetic distance (0 to 3%), suggests that they are conspecific with metacercariae found in fish across Mexico, Costa Rica, and Argentina. In light of the extensive diversity of fish species in Argentine freshwater ecosystems (over 500 species), and considering the relatively constrained extent of prior investigations, the anticipation of unearthing additional Clinostomum species or lineages is plausible. [ABSTRACT FROM AUTHOR]

Members of the genus Strigea Abildgaard, 1790 are endoparasites of birds distributed worldwide. Adults of an undescribed species of the genus Strigea were collected from the intestines of two hawk species (Rupornis magnirostris and Accipiter coperii). Other species identified as Parastrigea macrobursa that were described in Argentina were also recovered from two hawk species (Buteogallus urubitinga and Buteogallus anthracinus) in three localities along the coasts of Mexico. Specimens of the two species were sequenced for three molecular markers, the internal transcribed spacers locus (ITS1-5.8S rDNA- ITS2) and the domains D1–D3 from the large subunit from nuclear ribosomal DNA and the cytochrome c oxidase subunit 1 from mitochondrial DNA. The newly sequenced specimens were aligned with other strigeids sequences downloaded from GenBank. Maximum likelihood and Bayesian analyses inferred with each molecular marker revealed that our specimens of Strigea sp. formed an independent lineage, which is recognized herein as a new species, Strigea magnirostris n. sp., representing the first species in Mexico and the 16th in the Neotropical region. Morphologically, the new species is distinguished from other congeneric species from the Americas by having an oral sucker with several papillae around it, well-developed pseudosuckers (118–248 μm), a tegument covered with tiny spines, a larger cone genital (193–361 × 296–637) and a larger copulatory bursa (247–531 × 468–784). Our phylogenetic analyses revealed that P. macrobursa is not closely related to other members of the genus Parastrigea and is nested within Strigea , suggesting that P. macrobursa should be transferred to Strigea to form Strigea macrobursa n. comb., expanding its distribution range from Mexico to Argentina. Finally, the analyses also revealed that the taxonomy and systematics of Strigea should be re-evaluated, combining morphological and molecular characteristics. [ABSTRACT FROM AUTHOR]

The morphological and molecular (mitochondrial cytochrome c oxidase subunit I, COI) characterization of a new species of the subfamily Geoplaninae (Geoplanidae) supports the erection of a new genus, Anophthalmoplana gen. nov. The most remarkable feature of Anophthalmoplana horticola sp. nov. is the absence of eyes, a feature so far only recorded in one species of Geoplaninae, Geobia subterranea. Other features of the species are: a narrow, ribbon-shaped body; a gonopore near the posterior tip; a creeping sole almost as wide as body width; cylindrical pharynx; voluminous extrabulbar prostatic vesicle; protrusible penis papilla occupying the whole male atrium; a common ovovitelline duct dorsal to the female atrium; the atrium being lined by an epithelium with a stratified appearance. Based on the mtDNA phylogeny, the specimens studied here form a separate clade from the genus Geobia, thus contradicting its inclusion in this genus or any other of the subfamily Geoplaninae. These results reinforce the morphological differences observed, regarding internal anatomy, from Geobia and other members of Geoplaninae. [ABSTRACT FROM AUTHOR]

The most frequent causative agent of diphyllobothriosis, a fish-borne parasitic zoonosis, is the broad fish tapeworm Dibothriocephalus latus distributed mainly throughout the Holarctic region. The larval stages of the tapeworm were also detected in native and introduced freshwater fish in several lakes in South America, particularly in the north-western Patagonia in Argentina. The main objective of the present study was to determine the genetic structure of D. latus from rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), and brook trout (Salvelinus fontinalis) from Gutiérrez Lake and Alicura Reservoir in Argentina using the sequences of three mitochondrial genes (cox1, cob, and nad3) and six polymorphic microsatellite loci. The results were compared with the corresponding molecular data of D. latus from Europe (Switzerland and Italy; the Alpine lakes region) and Asia (Siberia, Russia). Only one concatenated haplotype identical with the con-Ha1 specific for D. latus from the Alpine lakes region was detected in all individuals from Argentina. Three different alleles were detected in five out of six analysed microsatellite loci, indicating the presence of three sets of chromosomes. The same structure of microsatellite loci was recently observed in D. latus from Switzerland and Italy, in which triploidy was previously confirmed by cytogenetic study. The data on the mitochondrial genes, the allelic structure of microsatellite loci, and the principal coordinate analysis showed close genetic relationships between D. latus from Argentina and the Alpine lakes region, thus supporting the hypothesis of the European origin of the broad fish tapeworm from South America. [ABSTRACT FROM AUTHOR]

Cline variation in ecoregion transition zones can provide strong evidence for adaptation to different environments. We describe the geographical gradations of phenotypes and genetic variation between two rodent species across an environmental gradient in northwestern Argentina. We applied an integrative analysis of the genetic (mtDNA) and phenotypic (skull morphometrics and pelage colorimetrics) variation in Graomys griseoflavus and G. chacoensis, at the margin of their ranges along a local transect between the Chaco and the Monte Desert ecoregions. We aimed to test the hypothesis that phenotypic clines between species corresponds with the transition between these two ecoregions. Molecular identification based on 777 bp of the mitochondrial cyt b evidenced that both species did not occur in syntopy and corroborated a marked genetic differentiation. Subtle species differences were evident in both skull morphometrics and pelage colorimetrics. Generalized additive models of phenotypic traits suggested an ecological and evolutionary interaction between species and their environment. The tympanic bullae traits showed a significant cline variation across the transition zone, both being greater in the specimens from the Monte Desert ecoregion. The phenotypic shift along the transect showed disparate patterns not always coincident with the transition between ecoregions. These patterns could arise by means of selection (or phenotypic plasticity) due to local conditions favoring different traits in populations inhabiting distinct environments. [ABSTRACT FROM AUTHOR]

The canid genus Lycalopex comprises six recently diversified South American species whose evolutionary relationships have been remarkably challenging to resolve. We analyzed 6000 bp of mitochondrial DNA (mtDNA) from 55 Lycalopex individuals (L. sechurae = 4, L. culpaeus = 7, L.griseus = 8, L.gymnocercus = 17, L.vetulus = 13 and L. fulvipes = 6), and nine specimens from the closely related species Cerdocyon thous, Chrysocyon brachyurus and Speothos venaticus, to reconstruct their phylogenetic relationships, estimate the support for species-level monophyly, and date their divergences. In addition, we also sequenced seven nuclear segments from the same taxa. Three different phylogenetic approaches converged on the same mitochondrial topology with strong support for most nodes. All species were confirmed to be monophyletic for mtDNA, except for one intriguing case in which two L. vetulus individuals carried L. gymnocercus haplotypes, potentially implying a case of interspecies admixture. L. vetulus was the first species to diverge (ca. 1.2 Mya), followed by L. sechurae and then L. gymnocercus. The most internal group comprised L. griseus and the sister-species L. culpaeus and L. fulvipes, which diverged around 430,000 years ago in southern Argentina or Chile. The analysis of nuclear markers revealed several examples of intra-specific variation coupled with lack of species monophyly, consistent with pervasive incomplete lineage sorting and/or hybridization in this recent radiation. Our results provide robust mitochondrial resolution of this challenging radiation, and illustrate the difficulty of attaining similar success with traditional nuclear markers. [ABSTRACT FROM AUTHOR]

Biological invasions can pose a severe threat to coastal ecosystems, but are difficult to track due to inaccurate species identifications and cryptic diversity. Here, we clarified the cryptic diversity and introduction history of the marine amphipod Ampithoe valida by sequencing a mtDNA locus from 683 individuals and genotyping 10,295 single-nucleotide polymorphisms (SNPs) for 349 individuals from Japan, North America and Argentina. The species complex consists of three cryptic lineages: two native Pacific and one native Atlantic mitochondrial lineage. It is likely that the complex originated in the North Pacific and dispersed to the north Atlantic via a trans-arctic exchange approximately 3 MYA. Non-native A. valida in Argentina have both Atlantic mitochondrial and nuclear genotypes, strongly indicating an introduction from eastern North America. In two eastern Pacific estuaries, San Francisco Bay and Humboldt Bay, California, genetic data indicate human-mediated hybridization of Atlantic and Pacific sources, and possible adaptive introgression of mitochondrial loci, nuclear loci, or both. The San Francisco Bay hybrid population periodically undergoes population outbreaks and profoundly damages eelgrass Zostera marina thalli via direct consumption, and these ecological impacts have not been documented elsewhere. We speculate that novel combinations of Atlantic and Pacific lineages could play a role in A. valida's unique ecology in San Francisco Bay. Our results reinforce the notion that we can over-estimate the number of non-native invasions when there is cryptic native structure. Moreover, inference of demographic and evolutionary history from mitochondrial loci may be misleading without simultaneous survey of the nuclear genome. [ABSTRACT FROM AUTHOR]

The biodiversity of Neotropical region is affected by anthropogenic disturbance. Throughout Brazil, Argentina and Uruguay, the native fish, Cnesterodon decemmaculatus, is well distributed and widely used as an excellent bioindicator of environmental quality. We investigated the diversity and genetic structure of its populations along a water pollution gradient to answer the following questions: 1- Does the genetic diversity decrease under the stressful conditions of a severe water quality gradient? and 2- Is there any relationship between the haplotypes registered along the studied basin and those recorded in other distant basins? Two mitochondrial DNA markers, Cytochrome b and D-loop, were analyzed and four haplotypes were registered for both markers along the basin. H1 was present throughout all the river sections in high frequencies leading to a low genetic diversity. We suggest that only a few haplotypes tolerate the stressful conditions of mountain rivers. On the other hand, the presence of H4 at the site located downstream suggests a history of recent colonization from the southeast to the northwest of the biome. These results, together with the abundance decrease along the pollution gradient, and the non-migratory characteristic of C. decemmaculatus suggest that its populations may be at risk of local extinction. [ABSTRACT FROM AUTHOR]

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As currently understood, the subgenus Abrothrix (Angelomys) Teta et al. (33:153–182, 2017) includes four species of small (< 25 g), short-tailed mice (< 65% of the length of the head plus body), widely distributed from southern Peru to southernmost Argentina and Chile. At least four nominal forms of this subgenus (i.e., canescens Waterhouse 2:109–27, 1837, hershkovitzi Patterson et al. (23:1–16, 1984), llanoi Pine (40:63–68, 1976), and xanthorhina Waterhouse 2:109–27, 1837), reach the southernmost portion of South America, being their taxonomy largely discussed during the last century. In this contribution we reviewed all these nominal forms, which were alternatively considered as valid at the species level or as subspecies of A. olivacea, (Waterhouse 2:109–27, 1837) based both on molecular (D-loop) and morphological (qualitative and quantitative) evidence. Phylogenetic and phylogeographic analysis of molecular data depicts a main break between north (= olivacea) and south (= xanthorhina) population of the Magellan Strait, which is moderately reflected in multivariate analysis of morphological cranial traits. Based on these results, the lack of qualitative craniodental differences among samples, plus additional genetic evidences (SNPs), we discuss some alternative taxonomic scenarios (i.e., if xanthorhina is a valid species or a subspecies of olivacea). Within this context, we advocated for the recognition at the subspecies level of the nominal forms hershkovitzi and llanoi, based on their large phenotypic distinctiveness and geographical isolation. We consider these data to be of utmost importance for the conservation of the biodiversity of the delicate island ecosystems of southernmost South America. [ABSTRACT FROM AUTHOR]

We conducted a revision of the Neotropical genus Acrobrycon. A previous study synonymized the species, A. ipanquianus, distributed from the western portion of the Amazon River to the north-western region of the La Plata River Basin, and A. tarijae, with type locality in the Lipeo River in Bolivia. We revisited this result by collecting new morphometric, meristic, and genetic data (COI mitochondrial gene) for 24 individuals distributed along La Plata River Basin in Argentina, and discussed our results in the context of multiple biogeographic processes of isolation in that basin. Our results revealed a more complex history of diversification and geographic distribution across Acrobrycon species than previously suspected, probably associated with multiple biogeographic processes of isolation in La Plata River Basin. We present new evidence that led us to reconsider the validity of A. tarijae, which is distinguishable from A. ipanquianus by the number of vertebrae (37-39 vs. 41-42) and pleural ribs (12-13 vs. 14). These results were also supported by our molecular analyses that revealed a genetic divergence >4% between A. ipanquianus and A. tarijae. We also identified two main genetic clusters within A. tarijae: the first cluster consisted of specimens from the Bermejo, Pilcomayo, Itiyuro and Juramento river basins (northern Argentina); and the second cluster included specimens from the southernmost basins, such as the Salí River in Tucumán, Cuarto River in the province of Cordoba and the Quinto River in the province of San Luis. Our results suggest that the genetic structure observed in A. tarijae is the result of the type of drainage (endorheic vs. exorheic) and geographical distance. [ABSTRACT FROM AUTHOR]

In Argentina, the family Diplostomidae is composed of eight genera: Austrodiplostomum Szidat & Nani; Diplostomum von Nordmann; Dolichorchis Dubois; Hysteromorpha Lutz; Neodiplostomum Railliet; Posthodiplostomum Dubois; Sphincterodiplostomum Dubois; and Tylodelphys Diesing. During a parasitological survey of fishes from the Iguazú National Park we detected diplostomid metacercariae in the brain of Erythrinus cf. erythrinus. Fish were caught using crab traps, transported alive to the field laboratory, cold-anaesthetized and euthanized by cervical dissection. Some metacercariae were heat-killed in water and fixed in 10% formalin and others were preserved in alcohol 96% for DNA extraction. They were sequenced for the partial segment of the 28S rDNA, internal transcribed spacer (ITS) rDNA and cytochrome c oxidase subunit I (COI) mtDNA genes. Phylogenetic reconstruction was carried out using Bayesian inference and the proportion (p) of absolute nucleotide sites (p-distance) was obtained. In the 28S rDNA tree, the metacercaria sequenced grouped as Dolichorchis sp. The COI mtDNA p-distance between the metacercariae with Dolichorchis lacombeensis was 0.01. There is a small number of ITS sequences for the Diplostomidae family deposited in the GenBank. The oral sucker, ventral sucker, holdfast organ and the distance between oral and ventral suckers are larger in the adult compared with the metacercariae. Additionally, hind-body length and width are larger in the adult due to the development of the genital complex. Further studies using an integrative approach will help confirm the affiliation of other species to the genus Dolichorchis. [ABSTRACT FROM AUTHOR]

With about 68 recognized living species, subterranean rodents of the genus Ctenomys are found in a multiplicity of habitats, from the dunes of the Atlantic coast to the Andes Mountains, including environments ranging from humid steppes of Pampas to the dry deserts of Chaco region. However, this genus needs an exhaustive reevaluation of its systematic and phylogenetic relationships regarding the different groups that compose it. This knowledge is essential to propose biodiversity conservation strategies both at species level and at higher hierarchical levels. In order to clarify the taxonomy and the recent evolutionary history from populations of Ctenomys in the Pampas region, Argentina, phylogenetic relationships among them were evaluated using mitochondrial DNA sequences: gene encoding cytochrome b protein (1,140 bp) and the non-coding D-loop region (434 bp). To infer the divergence times inside the Ctenomys clade, a Bayesian calibrate tree using fossil remains data from different families within Caviomorpha was performed at first. Secondly, that calibration data was used as priors in a new Bayesian phylogenetic inference within the genus Ctenomys. This phylogenetic tree emphasized on species currently distributed on the Pampas region, more precisely considering both the talarum and mendocinus groups. Bayesian inferences (BI) were integrated with the results of a Maximum Likelihood approach (ML). Based on these results, the distributional limits of the mendocinus and talarum groups appear to be related to the physiognomy of the Pampas region soils. On the other hand, the validity of C. pundti complex as a differentiated species of C. talarum is debated. According to previous evidence from morphological and chromosomal studies, these results show a very low divergence between those species that originally were classified within the talarum group. Mitochondrial DNA sequences from populations associated with these putative species have not recovered as reciprocal monophyletic groups in the phylogenetic analyses. In conclusion, C. talarum and C. pundti complex might be considered as the same biological species, or lineages going through a recent or incipient differentiation process. The results obtained in this study have important implications for conservation policies and practices, since both species are currently categorized as Vulnerable and Endangered, respectively. [ABSTRACT FROM AUTHOR]

Here we report the first complete mitochondrial genome of the semi-slug Omalonyx unguis (d'Orbigny, 1836) (Gastropoda: Succineidae). Sequencing was performed on a specimen from Argentina. Assembly was performed using Sanger data and Illumina next generation sequencing (NGS). The mitogenome was 13,984 bp in length and encoded the 37 typical Metazoan genes. A potential origin for mitochondrial DNA replication was found in a non-coding intergenic spacer (49 bp) located between cox3 and tRNA-Ile genes, and its secondary structure was characterized. Secondary structure models of the tRNA genes of O. unguis largely agreed with those proposed for other mollusks. Secondary structure models for the two rRNA genes were also obtained. To our knowledge, the 12S-rRNA model derived here is the first complete one available for mollusks. Phylogenetic analyses based on the mitogenomes of O. unguis and 37 other species of Stylommatophora were performed using amino acid sequences from the 13 protein-coding genes. Our results located Succineoidea as a sister group of Helicoidea + Urocoptoidea, similar to previous studies based on mitochondrial genomes. The gene arrangement of O. unguis was identical to that reported for another species of Succineoidea. The unique rearrangements observed for this group within Stylommatophora, may constitute synapomorphies for the superfamily. [ABSTRACT FROM AUTHOR]

The guitarfishes Pseudobatos horkelii and Pseudobatos percellens meet the criteria for threatened status as Critically Endangered (CR) and Endangered (EN), respectively. Both species occur in the Southern Atlantic Ocean. Considering the lack of data on the genetic structure of these species, the present study evaluated the genetic variability and population structure of the P. horkelii and P. percellens in the southern region of Brazil and the northern coast of Argentina, based on sequences of mitochondrial DNA, Control Region (D-loop). Samples of P. horkelii (n = 135) were analyzed in six localities situated in Northern Argentina, along the Brazilian states' coast. The mean of nucleotide diversity was 0.0053, the FST was 0.4277 and demographic analysis of P. horkelii suggests the existence of stability of the populations, with D = 0.9929, FS = 2.0155, SSD = 0.0817, R = 0.2153. In P. percellens (n = 101) were analyzed from six Brazilian localities along the coast of Santa Catarina, Paraná, and São Paulo. The mean nucleotide diversity was 0.0014 and FST value of 0.2921, the demographic analysis indicates a high migration rate of P. percellens among the localities evaluated, with D = 0.5222, FS = 0.3528, SSD = 0.01785, R = 0.3890. [ABSTRACT FROM AUTHOR]

Capuchin monkeys (genera Cebus and Sapajus) show a wide range distribution, from Honduras to Argentina. The aim of this work was to evaluate the genetic and phenotypic variability of captive specimens putatively belonging to S. cay (SCY) and S. nigritus (SNI) at their southernmost distribution limit. Forty-four individuals held in five captive centers from Argentina were analyzed based on external morphology, karyology and DNA sequences of mitochondrial control region (mtDNA-CR). Three morphotypes associated with their probable geographical origin in SCY and a single morphotype in SNI were found. For SCY we could associate each morphotype with the most frequent karyotype. SNI showed a single phenotype and a homogenous karyotype. Heterochromatin showed geographical patterns within species. A 515-bp mtDNA-CR fragment was sequenced, defining fourteen haplotypes at 59 polymorphic sites. A network constructed with our 14 haplotypes and other 77 from S. apella, S. macrocephalus, S. cay and S. nigritus from bibliography revealed some phylogeographic signals. Our SCY and SNI samples rendered four groups that differed in multiple mutational steps, with SCY being more similar to S. apella than to S. macrocephalus. Also, we identified two genetic divergent SCY groups: samples from NOA and from NEA with high mitochondrial diversity. Our results highlight the relevance of using complementary genetic tools throughout the distribution ranges of SCY and SNI for a better assessment of their diversity. [ABSTRACT FROM AUTHOR]

Human skeletal remains of an adult male (20–24 years old) and a juvenile (4–8 years old), dated to 750 ± 85 14C years BP, were found on the southern margin of Mar Chiquita Lagoon (Córdoba, Argentina). Both individuals show signs of being victims of interpersonal violence, with arrowheads associated with the remains and perimortem lesions on the juvenile, as well as an unusual form of burial, with the juvenile partially overlapped with the adult. The aim of this work is to study a possible kin relationship between these two individuals through ancient DNA analysis. Biological kinship was evaluated by autosomal and Y-chromosome STR (short tandem repeat) typing, PCR-APLP for SNP determination and hypervariable region I sequencing of the mitochondrial DNA. Genetic analyses indicated that these individuals shared the same Y-chromosomal haplotype but different mitochondrial lineages. The likelihood ratio based on autosomal loci indicates that the genetic profiles of the human remains would be more likely to be that indicating a father-son bond. The paleogenetic approach combined with forensic genetic methods applied to this study allowed us to confirm a hypothesis that originated in bioarchaeological evidence. This study constitutes a unique case in Argentina of kinship determination based on DNA profiles of human remains in an archaeological context of interpersonal violence. It is important to highlight the contribution made by these studies to address topics usually hidden in bioarchaeological studies, such as community organization, cultural customs and mortuary practices. [ABSTRACT FROM AUTHOR]

This study analyzed mtDNA sequences of two bottlenose dolphin subspecies found along the northern Patagonian coast, Argentina: the endangered Tursiops truncatus gephyreus and the data deficient Tursiops truncatus truncatus. Three haplotypes were recovered from nine samples. The most frequent haplotype represented the coastal morph, also two haplotypes showing falcate dorsal fin, a characteristic describing the oceanic morph. This finding suggests that both morphs may exist in sympatry in Argentina. Furthermore, sampling was extended beyond the species' previously known range, including individuals as far as seven hundred kilometers to the south. Therefore, new genetic data, despite being preliminary, hint at an unexpectedly higher genetic diversity of matrilines than previously anticipated. [ABSTRACT FROM AUTHOR]

The validity of subspecies designations in the common and wide-ranging Neotropical white peacock butterfly, Anartia jatrophae , has been debated for decades and remains an unsettled and contentious taxonomic issue among lepidopterists. Originally described by Linnaeus in the mid-18th century from specimens obtained from northern South America (Suriname), subsequent authors proposed a variety of subspecies names based on differences in adult external morphology among geographical populations. Many of these differences, however, were subsequently found to occur seasonally within populations, leading some to conclude that only a single polymorphic species should be recognized. Here, we have analysed both new and publicly available mitochondrial DNA barcodes, obtained from specimens collected from southern USA to northern Argentina, to assess whether they could provide insight into this long-standing controversy. Our molecular analyses, using a combination of character-based (nucleotide composition), population genetic and phylogenetic approaches, indicated the presence of at least four distinct genetic lineages that we suggest are distinct at the subspecies level, namely A. j. jatrophae , A. j. luteipicta , A. j. saturata and A. j. semifusca. Justification for these assignments and the proposed geographical distribution of each subspecies within the Americas are discussed. [ABSTRACT FROM AUTHOR]

The delimitation of fishery stocks is an important aspect for the development and implementation of fishery stock management and sustainable use programs. Genetic analyses can provide useful information for the definition of population units, migration rates and changes in effective population sizes over long time frames. The black drum Pogonias courbina (Lacepede, 1803) is a marine fish that inhabits estuaries, bays and coastal waters of both hemispheres of the Western Atlantic, including Brazil, Uruguay and Northern Argentina. Intensely exploited at the Lagoa dos Patos Estuary in South Brazil, it is considered locally collapsed and since 2014 it is included in the National List of Endangered Fauna. Here we studied the population genetics of Pogonias courbina from South Brazil and the Argentinean and Uruguayan margins of the Río de la Plata Estuary, using the mitochondrial DNA control region. We showed that along the study area Pogonias courbina groups present high genetic diversity, no genetic structure, and are undergoing slight expansion. These characteristics favor resilience of the population, decreasing the extinction risk of local stocks. However, the slow recovery after the black drum fisheries collapse at Lagoa dos Patos indicates that the recolonization process is slow; this is corroborated by migration estimates, in which we observe a low number of migrants between Argentina/Uruguay and South Brazil. Therefore, we suggest that the South Brazil reproductive stock, impacted by regional fisheries, can be considered a unique stock in terms of management, independent of Uruguayan and Argentinean management strategies. However, an integrated management plan should ideally be considered for these groups, since impacts and conservation efforts are likely shared between areas. [ABSTRACT FROM AUTHOR]

In the present study, we analysed the genetic structure of Triatoma infestans populations with a phylogeographical approach using sequences of the mitochondrial NADH dehydrogenase subunit 5 (ND5) and the nuclear elongation factor-1 alpha (EF-1α) genes of bugs obtained from Argentina and Bolivia. Spatially circumscribed haplogroups were distinguished from the ND5 gene sequences, one distributed exclusively to the south of the studied area and, in agreement with the results from the EF-1α gene, one haplogroup limited to Bolivia and another to Morajú located in the Chaco region of Argentina. In both the ND5 and EF-1α networks, the most widespread haplogroup or allele group showed a star-like topology, which is compatible with a recent demographic expansion. The asymmetric historical gene flow detected from a population of the Chaco region towards Bolivia and the spatiotemporal phylogeographical reconstruction of lineage dispersal would support the hypothesis that postulates the Chaco biogeographical region as the area of origin for the species. However, additional studies with a broader sampling in the Andean region are needed to define with certainty whether the origin of T. infestans is Chacoan or Andean. [ABSTRACT FROM AUTHOR]

Leopardus geoffroyi is a small feline with a widespread distribution in a broad array of habitats. Here we investigate its evolutionary history to characterize the phylogeographical patterns that led to its present distribution using mitochondrial DNA from 72 individuals collected throughout its entire range. All haplotypes conformed to a monophyletic group, including two clades with a central/marginal disposition that is incongruent to the proposed subspecies. Spatial diffusion analysis showed the origin of the species within the oldest and more diverse central clade. A Bayesian Skyline Plot combined with a dispersal through time plot revealed two population increases at 190 000–170 000 and 45 000–35 000 years ago, the latter period accompanied by an increase in the dispersal rate. Species distribution models showed similar patterns between the present and Last Interglacial Period, and a reduction of high-probability areas during the Last Glacial Maximum (LGM). Molecular evidence confirms L. geoffroyi as a monotypic species whose origin is located in Central Argentina. The last glaciation had little effect on the pattern of distribution of the species: the population and range expansion that started before the LGM, although probably being halted, continued after the glaciation and resulted in the presence of this felid in the far south of Patagonia. [ABSTRACT FROM AUTHOR]

Varroa destructor, a parasitic mite of the western honey bee, Apis mellifera L., is a serious threat to colonies and beekeeping worldwide. Population genetics studies of the mite have provided information on two mitochondrial haplotypes infecting honey bee colonies, named K and J (after Korea and Japan, respectively, where they were originally identified). On the American continent, the K haplotype is much more prevalent, with the J haplotype only detected in some areas of Brazil. The aims of the present study were to assess the genetic diversity of V. destructor populations in the major beekeeping region of Argentina and to evaluate the presence of heteroplasmy at the nucleotide level. Phoretic mites were collected from managed A. mellifera colonies in ten localities, and four mitochondrial DNA (mtDNA) regions (COXI, ND4, ND4L, and ND5) were analyzed. Based on cytochrome oxidase subunit I (COXI) sequencing, exclusively the K haplotype of V. destructor was detected. Furthermore, two sub-haplotypes (KArg-N1 and KArg-N2) were identified from a variation in ND4 sequences and the frequency of these sub-haplotypes was found to significantly correlate with geographical latitude. The occurrence of site heteroplasmy was also evident for this gene. Therefore, ND4 appears to be a sensitive marker for detecting genetic variability in mite populations. Site heteroplasmy emerges as a phenomenon that could be relatively frequent in V. destructor. [ABSTRACT FROM AUTHOR]

The South American plains vizcacha, Lagostomus maximus inhabits primarily the Pampean and adjoining Espinal, Monte and Chaquenean regions of Argentina. In order to study the population genetic structure of L. maximus, a fragment of 560 bp of the mitochondrial DNA hypervariable region 1from 90 individuals collected from the 3 subspecies and 8 groups along Argentina was amplified and analyzed. We found 9 haplotypes. The haplotype network did not show an apparent phylogeographical signal. Although low levels of genetic variation were found in all the subspecies and groups analyzed, a radiation of L. maximus would have occurred from the North and Center of the Pampean region toward the rest of its geographic range in Argentina. Low levels of genetic diversity, the existence of a single genetically distinct population in Argentina and changes of its effective size indicate that metapopulation processes and changes in human population dynamics during the late-Holocene were important factors shaping the population genetic structure of L. maximus in Argentina. [ABSTRACT FROM AUTHOR]

Aim: To investigate the structure and rate of gene flow among populations of habitat‐specialized species to understand the ecological and evolutionary processes underpinning their population dynamics and historical demography, including speciation and extinction. Location: Peruvian and Argentine Andes. Taxon: Two subspecies of torrent duck (Merganetta armata). Methods: We sampled 156 individuals in Peru (M. a. leucogenis; Chillón River, n = 57 and Pachachaca River, n = 49) and Argentina (M. a. armata; Arroyo Grande River, n = 33 and Malargüe River, n = 17), and sequenced the mitochondrial DNA (mtDNA) control region to conduct coarse and fine‐scale demographic analyses of population structure. Additionally, to test for differences between subspecies, and across genetic markers with distinct inheritance patterns, a subset of individuals (Peru, n = 10 and Argentina, n = 9) was subjected to partial genome resequencing, obtaining 4,027 autosomal and 189 Z‐linked double‐digest restriction‐associated DNA sequences. Results: Haplotype and nucleotide diversities were higher in Peru than Argentina across all markers. Peruvian and Argentine subspecies showed concordant species‐level differences (ΦST mtDNA = 0.82; ΦST autosomal = 0.30; ΦST Z chromosome = 0.45), including no shared mtDNA haplotypes. Demographic parameters estimated for mtDNA using IM and IMa2 analyses, and for autosomal markers using ∂a∂i (isolation‐with‐migration model), supported an old divergence (mtDNA = 600,000 years before present (ybp), 95% HPD range = 1.2 Mya to 200,000 ybp; and autosomal ∂a∂i = 782,490 ybp), between the two subspecies, characteristic of deeply diverged lineages. The populations were well‐differentiated in Argentina but moderately differentiated in Peru, with low unidirectional gene flow in each country. Main conclusions: We suggest that the South American Arid Diagonal was preexisting and remains a current phylogeographic barrier between the ranges of the two torrent duck subspecies, and the adult territoriality and breeding site fidelity to the rivers define their population structure. [ABSTRACT FROM AUTHOR]

• Species limits tested with an extensive geographic sample and thousands of SNPs. • Genome-wide data supports six candidate species for the L. wiegmannii complex. • First diversification of the complex occurred during the Lower Pleistocene. • Quaternary sand dune expansion might have influenced early speciation in the complex. Coalescent-based algorithms coupled with the access to genome-wide data have become powerful tools for assessing questions on recent or rapid diversification, as well as delineating species boundaries in the absence of reciprocal monophyly. In southern South America, the diversification of Liolaemus lizards during the Pleistocene is well documented and has been attributed to the climatic changes that characterized this recent period of time. Past climatic changes had harsh effects at extreme latitudes, including Patagonia, but habitat changes at intermediate latitudes of South America have also been recorded, including expansion of sand fields over northern Patagonia and Pampas). In this work, we apply a coalescent-based approach to study the diversification of the Liolaemus wiegmannii species complex, a morphologically conservative clade that inhabits sandy soils across northwest and south-central Argentina, and the south shores of Uruguay. Using four standard sequence markers (mitochondrial DNA and three nuclear loci) along with ddRADseq data we inferred species limits and a time-calibrated species tree for the L. wiegmannii complex in order to evaluate the influence of Quaternary sand expansion/retraction cycles on diversification. We also evaluated the evolutionary independence of the recently described L. gardeli and inferred its phylogenetic position relative to L. wiegmannii. We find strong evidence for six allopatric candidate species within L. wiegmannii, which diversified during the Pleistocene. The Great Patagonian Glaciation (∼1 million years before present) likely split the species complex into two main groups: one composed of lineages associated with sub-Andean sedimentary formations, and the other mostly related to sand fields in the Pampas and northern Patagonia. We hypothesize that early speciation within L. wiegmannii was influenced by the expansion of sand dunes throughout central Argentina and Pampas. Finally, L. gardeli is supported as a distinct lineage nested within the L. wiegmannii complex. [ABSTRACT FROM AUTHOR]

Genetic studies on pre-Hispanic populations of the Southern Andes have been increasing steadily in the last decade. Nevertheless, ancient DNA characterization of Formative Period archaeological human remains is particularly scant, especially for Northwest Argentina. To expand current information on genetic characterization of the first agricultural communities of the southern Calchaquí Valleys, we present and discuss the first mitochondrial ancient DNA information obtained on samples dated to ca. 3,600–1,900 years before present from the Cajón Valley, Catamarca Province. Reproducible mtDNA hypervariable region 1 (HVR-1) sequences were obtained in seven individuals. Mitochondrial HVR-1 haplotypes were assigned to three of the four founding haplogroups, D1 (57.1%), C1 (28.5%), and B2 (14.2%), with absence of A2. Our results show that the Cajón Valley sample, with predominance of D1 and C1, differs from that commonly observed in ancient and modern Andean populations, which usually show a high prevalence of haplogroup B2. The fact that the Cajón Valley and Pampa Grande (Salta Province, Argentina) share a prevalence of haplogroup D1 could provide additional evidence to support possible genetic affinities between the valleys and the eastern sub-Andean region during the Formative Period in Northwest Argentina, expanding the archaeological evidence of contact between both populations. Future complete mitogenomic analysis will provide substantial information to formulate new hypotheses about the origins and phylogenetic relationships between the individuals of the Cajón Valley and other groups from the Andes, Gran Chaco, and the Amazon. [ABSTRACT FROM AUTHOR]

Hydrochoerus hydrochaeris is an herbivorous rodent that inhabits most wetlands of South America. It is a well-known species, but studies about their population genetics are scarce. The aim of this study was to analyze the genetic diversity, population genetic structure and historical population dynamics of the species in the Chaco-pampean region, using mitochondrial DNA control region sequences and a non-invasive sampling design. Our results showed the existence of four haplogroups in the study area. Haplogroup I is composed by individuals from most of the study area, while the remaining include individuals from some sites in Paraguay (haplogroups III and IV) or Argentina (haplogroup II). The genetic diversity was low in haplogroups I, III and IV. Our results suggest that the Paraná and Paraguay rivers would be acting as a migration corridor for the species. Historical population dynamics analyses and haplotype network showed past population expansions and secondary contact between haplogroups I–II and I–IV, which could be related to past climatic events such as the Iberá Wetlands formation. These results must be taken as working hypotheses for future studies about the population genetics of capybara and related species inhabiting the region. [ABSTRACT FROM AUTHOR]

Here, we examine the genetic diversity in the agricultural pest Nezara viridula (Linnaeus,) from populations of Argentina using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. The DNA sequence comparisons of 718 base pairs of the COI gene revealed seven haplotypes. The observed total haplotype diversity (Hd) value was of 0.138, and the nucleotide diversity was of 0.00039 and 0.00135 according to π and θW, respectively. Eight out of the 10 populations analysed, mostly from soya bean crops, only presented the more frequent haplotype, while 2 haplotypes were found in a mixed culture and 6 haplotypes in a peanut culture. Factors such as differential insecticide applications, as well as the surrounding habitat, and the host plant preference could be related to the genetic diversity differences observed among samples of N. viridula. The analysis of genetic diversity in samples collected in crops treated and non‐treated with insecticides, as well as in samples collected from different seasons, could help to clarify the role of the factors that led to the pattern of genetic diversity detected in this study. The result of a comparative analysis of COI gene sequences among populations from South America, Africa, Asia and Europe was consistent with the hypothesis of an African origin of N. viridula. On the other hand, the haplotypes of Europe were clustered with haplotypes from South America. In addition, specimens from Madeira (west of Europe) shared ancestry with South America and Europe. It has been suggested that a probable route of colonization of America could have been from Western Europe towards the eastern coasts of South America. [ABSTRACT FROM AUTHOR]

The lizard genus Phymaturus comprises two reciprocally monophyletic clades: Phymaturus palluma and Phymaturus patagonicus. Species belonging to the P. patagonicus clade occur in extra-Andean Patagonia, and some of them remain with unresolved phylogenetic relationships after studies based on morphological and nuclear and mitochondrial DNA (mtDNA) evidence. Here, we elucidate the taxonomic status of five putative species originally described according to morphotypes based upon morphometric and meristic characteristics and dorsal colour pattern: Phymaturus agilis, Phymaturus excelsus, Phymaturus manuelae, Phymaturus spectabilis and Phymaturus spurcus. We amplified a 657 bp fragment of COI mtDNA from 23 individuals and a 2708 bp fragment of cytochrome b, ND1, ND2 and eight transfer RNAs from another 114 individuals. We found strong support for two reciprocally monophyletic genetic lineages: a small clade for P. manuelae and a large polytomic clade for the rest of the presumed species. A haplotype network analysis unveiled a genetic structure for lineages in the large clade, suggesting that morphological differences are a consequence of population divergence. To complement the molecular analyses, we estimated morphotype proportions in populations and estimated morph heritability with the regression of offspring on females bearing species-typical phenotypes. Our results indicate that P. agilis, P. excelsus, P. spectabilis and P. spurcus compose a single highly structured species. [ABSTRACT FROM AUTHOR]

The Basque Diaspora in Western USA and Argentina represents two populations which have maintained strong Basque cultural and social roots in a completely different geographic context. Hence, they provide an exceptional opportunity to study the maternal genetic legacy from the ancestral Basque population and assess the degree of genetic introgression from the host populations in two of the largest Basque communities outside the Basque Country. For this purpose, we analyzed the complete mitochondrial DNA control region of Basque descendants living in Western USA (n = 175) and in Argentina (n = 194). The Diaspora populations studied here displayed a genetic diversity in their European maternal input which was similar to that of the Basque source populations, indicating that not important founder effects would have occurred. Actually, the genetic legacy of the Basque population still prevailed in their present-day maternal pools, by means of a haplogroup distribution similar to the source population characterized by the presence of autochthonous Basque lineages, such as U5b1f1a and J1c5c1. However, introgression of non-Basque lineages, mostly Native American, has been observed in the Diaspora populations, particularly in Argentina, where the quick assimilation of the newcomers would have favored a wider admixture with host populations. In contrast, a longer isolation of the Diaspora groups in USA, because of language and cultural differences, would have limited the introgression of local lineages. This study reveals important differences in the maternal evolutionary histories of these Basque Diaspora populations, which have to be taken into consideration in forensic and medical genetic studies. [ABSTRACT FROM AUTHOR]

The present study evaluated the possible occurrence of cryptic species among Merluccidae from Argentina by examining sequences of cytochrome c oxidase subunit I ( coI) mtDNA. This approach can discriminate Merluccius hubbsi and Merluccius australis; specimens with morphological diagnostic characters of Merluccius patagonicus formed a cohesive cluster with M. hubbsi specimens. BIN analysis confirmed the effectiveness of barcoding within a global context. [ABSTRACT FROM AUTHOR]

Information on distribution and hosts of hard ticks of northern Misiones Province in Argentina is presented in this study. Ticks were identified by morphological characters and by sequences of a 410 bp fragment of the mitochondrial 16S rRNA gene. A total of 292 ticks collected from the environment and wild and domestic mammals were identified: Amblyomma coelebs, A. brasiliense, A. dubitatum, A. incisum, A. ovale, Haemaphysalis juxtakochi and Rhipicephalus microplus. The presence of A. coelebs was confirmed for Argentina and the first record of H. juxtakochi in Misiones was presented. Some of the species as A. incisum, A. ovale and R. microplus are ticks of medical and veterinary importance. Therefore, further studies on the vectorial role of these species in Misiones Province are necessary to determine their epidemiological relevance. [ABSTRACT FROM AUTHOR]

• A new Hymenolepis species is described parasitizing Sigmodontine rodents in Argentina. • An update of species in Hymenolepididae from rodents is provided. • Hymenolepis species from North-South American rodents are morphologically analyzed. • Phylogenetic inferences of Hymenolepididae from rodents are proposed. Rodents are hosts of a wide diversity of cestodes. Fifteen genera included in the family Hymenolepididae parasitize rodents, and only four of these genera have been recorded from the Neotropical region. The purpose of this paper is to update species of Hymenolepididae from rodents, describe a new species of Hymenolepis based on morphological and molecular characterization (ITS1 rDNA and cox1 mtDNA), comparing the features among the species from North and South American rodents, and provide phylogenetic inferences of Hymenolepididae from rodents based on sequences available in the GenBank. Rodents were collected in the Parque Provincial Ernesto Tornquist, Buenos Aires, Argentina. Hymenolepis ivanovae n. sp. differs from other Hymenolepis species registered from North and South American rodents by body size, scolex, suckers, cirrus sac, cirrus, testes, and eggs, among others. Comparative morphometric data for Hymenolepis species from North and South American rodents is provided. Molecular analyses place H. ivanovae n. sp. within the genus Hymenolepis with strong support, and show it close to species of zoonotic importance. The new species is the first species of Hymenolepis described from Sigmodontinae rodents. [Display omitted] [ABSTRACT FROM AUTHOR]

The genus Aylacostoma Spix, 1827, is mainly endemic to South America, and comprises about 30 nominal species, most of which were described based solely on conchological features following the typological approaches of most of the 19th and the mid-20th century authors. Here, we redescribe Aylacostoma chloroticum Hylton Scott, 1954, and describe A ylacostoma brunneum sp. nov. from the High Paraná River ( Argentina- Paraguay) by means of morphological and molecular characters. Both are threatened species currently included into an ongoing ex situ conservation programme, as their habitats have disappeared because of damming and the filling up of the Yacyretá Reservoir in the early 1990s. We used DNA sequences from cytochrome b and cytochrome oxidase subunit I ( COI) genes to estimate their genetic distances, and the COI sequences were also used to assess their specific status under the evolutionary genetic species concept by means of the K/θ method. Our results clearly demonstrate that both must be recognized as evolutionary genetic species, despite only minor differences in morphological characters other than in the shells. © 2014 The Linnean Society of London [ABSTRACT FROM AUTHOR]

Squirrels have been traded in the pet market for several decades, and numerous species have established in the wild. The Asiatic speciesCallosciurus erythraeusandCallosciurus finlaysoniihave been introduced into other parts of Asia, in Europe and South America. In this study, (1) we conducted a genetic characterization ofC. erythraeusintroduced into Argentina and compared them with native and introduced populations in Asia, and (2) we analyzed genetic variation among the four invasion foci in Argentina in order to corroborate that the pathway of invasion was a single introduction event in the country and subsequent translocations. We analyzed mitochondrial (cytochrome b, Cyt b; cytochrome oxidase c subunit I, COI and D-loop) and nuclear (recombination activating gene I, RAGI) DNA markers using the classical method (DNA barcoding gap analysis) and also the Automatic Barcode Gap Discovery method (ABGD). The markers D-loop, COI, and RAG1 indicated that the introduced squirrels from the different invasion foci formed a monophyletic group that, together with only one haplotype for the D-loop and COI markers, supported the hypothesis of one introduction event into Argentina followed by subsequent translocations. Unexpectedly, sequences from squirrels captured in Argentina were more related toC. finlaysoniithan toC. erythraeusfor D-loop and Cyt b markers. However, intraspecific variation among sequences ofC. erythraeusbelonging to different subspecies or collected in different regions was large and comparable with the distance to the sequences from Argentina. The ABGD method also indicated large genetic variability withinC. erythraeusand close proximity between squirrels from Argentina andC. finlaysonii. The complex taxonomy ofCallosciurus, as occurs with the sister speciesC. erythraeusandC. finlaysonii, requires a thorough systematic revision. A simultaneous analysis of diagnostic morphological characters and genetic markers is needed and will provide new insight regarding the worldwide invasion of Asiatic squirrels. [ABSTRACT FROM AUTHOR]

Sub-population structure and intricate kinship dynamics might introduce biases in molecular anthropology studies and could invalidate the efforts to understand diseases in highly admixed populations. In order to clarify the previously observed distribution pattern and morbidity of Chagas disease in Gran Chaco, Argentina, we studied two populations (Wichí and Criollos) recruited following an innovative bio-cultural model considering their complex cultural interactions. By reconstructing the genetic background and the structure of these two culturally different populations, the pattern of admixture, the correspondence between genealogical and genetic relationships, this integrated perspective had the power to validate data and to link the gap usually relying on a singular discipline. Although Wichí and Criollos share the same area, these sympatric populations are differentiated from the genetic point of view as revealed by Non Recombinant Y Chromosome genotyping resulting in significantly high Fst values and in a lower genetic variability in the Wichí population. Surprisingly, the Amerindian and the European components emerged with comparable amounts (20%) among Criollos and Wichí respectively. The detailed analysis of mitochondrial DNA showed that the two populations have as much as 87% of private haplotypes. Moreover, from the maternal perspective, despite a common Amerindian origin, an Andean and an Amazonian component emerged in Criollos and in Wichí respectively. Our approach allowed us to highlight that quite frequently there is a discrepancy between self-reported and genetic kinship. Indeed, if self-reported identity and kinship are usually utilized in population genetics as a reliable proxy for genetic identity and parental relationship, in our model populations appear to be the result not only and not simply of the genetic background but also of complex cultural determinants. This integrated approach paves the way to a rigorous reconstruction of demographic and cultural history as well as of bioancestry and propensity to diseases of Wichí and Criollos. [ABSTRACT FROM AUTHOR]

Abstract: The spectacled porpoise (Phocoena dioptrica, Lahille, 1912) is one of the cetacean species about which least is known. Most information on the biology and ecology of this species has been obtained from stranded specimens and sightings at sea. In this study, analysis of 380bp fragment of mitochondrial DNA (mtDNA) control region sequences (N =50) was performed to provide a preliminary assessment of the genetic variation in spectacled porpoise specimens found stranded or by caught on the coast of Tierra del Fuego, Argentina. Results showed high levels of mtDNA diversity, as expected in large size and stable populations, and similar to other species of porpoises. The star-like shape phylogeny of haplotypes indicates a recent population expansion. This is the first report on the genetic variation of this species. Other lines of evidence (microsatellite loci, single-nucleotide polymorphism (SNPs)) are needed to improve our knowledge on the molecular biology of the spectacled porpoise. [Copyright &y& Elsevier]