Sérgio Luiz Althoff

DNA Barcoding of Sigmodontine Rodents: Identifying Wildlife Reservoirs of Zoonoses

Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments.

Variações na coloração de iraras (Eira barbara Linnaeus, 1758 - Carnivora, Mustelidae) da Reserva Biológica Estadual do Sassafrás, Santa Catarina, sul do Brasil

Tayras present color variations along their range of distribution. The objective of this study is to contribute to the understanding of these variations. In the State Biological Reserve of Sassafras, Santa Catarina, Brazil, 21 photographic records of tayras were obtained, comprising different coat colors. Two coat color classes were observed among photographed individuals: dark body with gray head and neck, and body, head and neck homogeneously white-yellowish. The frequency of records did not varied significantly between the two color classes, indicating that the white-yellowish coloration is common for this local population.

A new species of swamp rat of the genus Scapteromys Waterhouse, 1837 (Rodentia: Sigmodontinae) endemic to Araucaria angustifolia Forest in Southern Brazil

A new species of swamp rat of the genus Scapteromys from the Meridional Plateau of Southern Brazil is described. Morphological, molecular, and karyological analysis support the recognition of the new species, distinct from S. aquaticus and S. tumidus. Scapteromys sp. nov. is significantly smaller than the congeneric taxa considering most of the external and craniometric measurements and the pelage is conspicuously grayer and darker. It can be distinguished from S. tumidus by the laterally extended thenar pad of the manus and the parallel edges of the hamular process of the pterygoid, and from S. aquaticus by a grayer and darker pelage and smaller values of most external and craniometric measurements. Karyological analysis indicated a difference in chromosome numbers across the distributional range: 2n=34 and 2n=36. A total of 11 haplotypes were found along the range of the new species within the biogeographic province of Araucaria angustifolia Forest. Strongly supported substructure was found within the new taxon, resulting in two reciprocally monophyletic clades.

Mammalia, Myrmecophagidae, Myrmecophaga tridactyla (Linnaeus, 1758) and Cervidae, Ozotoceros bezoarticus (Linnaeus, 1758): contribution to the knowledge of the historical distribution in Santa Catarina, southern Brazil

The present study reports historical records of Myrmecophaga tridactyla and Ozotoceros bezoarticus from the north plateau of Santa Catarina state, southern Brazil, thus contributing to the knowledge about the distribution of these species. The possible causes of the extinction of Ozotoceros bezoarticus are also discussed as well as management tactics to conserve these species in southern Brazil.

Pleistocene climatic oscillations in Neotropical open areas: Refuge isolation in the rodent Oxymycterus nasutus endemic to grasslands

Pleistocene climatic oscillations favoured the expansion of grassland ecosystems and open vegetation landscapes throughout the Neotropics, and influenced the evolutionary history of species adapted to such environments. In this study, we sampled populations of the rodent Oxymycterus nasutus endemic to open areas in the Pampas and Atlantic Forest biomes to assess the tempo and mode of population divergence using an integrative approach, including coalescence theory, ecological niche models, and morphometry. Our results indicated that these O. nasutus populations exhibited high levels of genetic structure. Six major mtDNA clades were found, structuring these biomes into distinct groups. Estimates of their divergence times was indicated to be 0.571 myr. The high degree of genetic structure is reflected in the analyses of geometric morphometric; skull differences between lineages in the two ecoregions were detected. During the last glacial maximum, there was a strong increase in suitable abiotic conditions for O. nasutus. Distinct molecular markers revealed a population expansion over time, with a possible demographic retraction during the post-glacial period. Considering that all clades coalesce with the last interglacial maximum, our results indicated that reduction in suitable conditions during this period may have resulted in a possible vicariance associated with refuge isolation.

Contrasting patterns of RUNX 2 repeat variations are associated with palate shape in phyllostomid bats and New World primates

Establishing the genetic basis that underlies craniofacial variability in natural populations is one of the main topics of evolutionary and developmental studies. One of the genes associated with mammal craniofacial variability is RUNX2, and in the present study we investigated the association between craniofacial length and width and RUNX2 across New World bats (Phyllostomidae) and primates (Catarrhini and Platyrrhini). Our results showed contrasting patterns of association between the glutamate/alanine ratios (Q/A ratio) and palate shape in these highly diverse groups. In phyllostomid bats, we found an association between shorter/broader faces and increase of the Q/A ratio. In New World monkeys (NWM) there was a positive correlation of increasing Q/A ratios to more elongated faces. Our findings reinforced the role of the Q/A ratio as a flexible genetic mechanism that would rapidly change the time of skull ossification throughout development. However, we propose a scenario in which the influence of this genetic adjustment system is indirect. The Q/A ratio would not lead to a specific phenotype, but throughout the history of a lineage, would act along with evolutionary constraints, as well as other genes, as a facilitator for adaptive morphological changes.

First record of Molossops neglectus Williams & Genoways, 1980 (Chiroptera, Molossidae) from the state of Santa Catarina, southern Brazil

Herein we describe the first records of Molossops neglectus for the state of Santa Catarina, Brazil. The records are based on 3 specimens captured in the municipalities of Chapecó and São Domingos, in the western portion of the state. Considering that M. neglectus is an infrequent species in field surveys, new data on its geographical range is important to better understand the biology and ecology of M. neglectus.

Coxiella and Bartonella spp. in bats (Chiroptera) captured in the Brazilian Atlantic Forest biome

BackgroundThe role of bats as reservoirs of zoonotic agents, especially pathogenic bacteria such as Bartonella and Coxiella, has been discussed around the world. Recent studies have identified bats as potential hosts of species from the proteobacteria phylum. In Brazil, however, the role of bats in the natural cycle of these agents is poorly investigated and generally neglected. In order to analyze the participation of bats in the epidemiology of diseases caused by Bartonella, Coxiella, Rickettsia, Anaplasma and Ehrlichia, we conducted a descriptive epidemiological study in three biogeographic regions of the Brazilian Atlantic Forest.ResultsTissues of 119 bats captured in preserved areas in the states of Rio de Janeiro, Bahia and Santa Catarina from 2014 to 2015 were submitted to molecular analysis using specific primers. Bartonella spp. was detected in 22 spleen samples (18.5%, 95% CI: 11.9–26.6), whose phylogenetic analysis revealed the generation of at least two independent clusters, suggesting that these may be new unique genotypes of Bartonella species. In addition, four samples (3.4%, 95% CI: 0.9–8.3) were positive for the htpAB gene of C. burnetii [spleen (2), liver (1) and heart (1)]. Rickettsia spp., Anaplasma and Ehrlichia were not identified. This is the first study reporting C. burnetii and Bartonella spp. infections in bats from the Atlantic Forest biome.ConclusionsThese findings shed light on potential host range for these bacteria, which are characterized as important zoonotic pathogens.

Expansion of the southern limit of Vampyrodes caraccioli Thomas, 1889 (Chiroptera, Phyllostomidae) and first record for Santa Catarina state, southern Brazil

Three specimens of Vampyrodes caraccioli were collected in Corupá and São Bento do Sul, in Santa Catarina state, increasing its geographic distribution extension by 170 km south. These specimens also represent the first record for the species in Santa Catarina. The knowledge about bats in Santa Catarina has increased in recent years, showing the need of basic studies about richness and diversity in different regions.

Range extension of the Atlantic Forest Hocicudo, Oxymycterus dasytrichus (Schinz, 1821), to the state of Santa Catarina, southern Brazil

Six individuals of Oxymycterus dasytrichus (Schinz, 1821) were found on the coast of Parana and Santa Catarina (in the Atlantic Forest), expanding the known geographical distribution of the species ca. 280 km southward. The specimens represent the first record of the species for the state of Santa Catarina, and new localities to the region of southern Parana. The identification of the species relied mainly on interspecies comparative assessment of genetic distance based on DNA sequences data from the mitochondrial cytochrome- b gene and geographic distribution of taxa across biomes, particularly in the Atlantic Forest. Our findings highlight the role of protected areas, particularly the Guaraquecaba Environmental Protection Area, to preserve small mammals.