A new species of Akodon Meyen, 1833 (Rodentia: Cricetidae) from dry forests of the Amazonia-Cerrado transition.

Akodon is the most diverse genus of the tribe Akodontini, comprising 41 extant species. Although distributed in a wide range of environments in South America, the genus was long considered to be absent from Amazon Forest. Nonetheless, in recent decades, records of Akodon have been reported based on specimens from southern Amazonia, throughout the contact zone with Cerrado. Published data about the unique karyotype (2n=10), along with evidence of sister phylogenetic relationship (Cytb sequences) with Akodon cursor, a species from the Atlantic Forest, suggest that these specimens represent an undescribed species. Herein we hypothesize that these samples represent a new species of Akodon from Amazonia-Cerrado transitional areas. Through the analyses of 217 specimens from Mato Grosso and Pará states, Brazil, as well as 336 specimens of Akodon cursor species group from the Atlantic Forest, we provide qualitative and quantitative external and craniodental data that support their distinction in comparison with other congeners. The sister relationship between this new species and A. cursor provide additional evidence of a past connection between the two largest tropical forests of South America. Moreover, the recognition of Akodon n. sp. points to the presence of the genus in the Amazonia-Cerrado transition, an area currently under great anthropic pressure, highlighting the fact that we might be losing a portion of Brazilian biodiversity before even getting to know it.

Detection of Bartonella sp. and a novel spotted fever group Rickettsia sp. in Neotropical fleas of wild rodents (Cricetidae) from Southern Brazil.

The Neotropical region shows a great diversity of fleas, comprising more than 50 genera. The importance of the study of fleas is linked to their potential role as disease vectors. The aim of this study is to investigate the presence of Rickettsia spp. and Bartonella spp. in Neotropical fleas collected from wild rodents in Southern Brazil. From 350 rodents captured, 30 were parasitized by fleas. A total of 61 fleas belonging to two genera and six different species were collected (Craneopsylla minerva minerva, Polygenis occidentalis occidentalis, Polygenis platensis, Polygenis pradoi, Polygenis rimatus, and Polygenis roberti roberti). In 13 % of fleas of three different species (C. minerva, P. platensis, and P. pradoi) Rickettsia sp. DNA was found. Phylogenetic analysis of concatenated sequences of gltA, htrA, and ompA genes showed that Rickettsia sp. found in rodent fleas (referred as strain Taim) grouped together with Spotted Fever Group Rickettsia. In reference to Bartonella spp., five genotypes were identified in seven fleas of two species (C. minerva and P. platensis) and in five rodent spleens. Also, 207 frozen samples of wild rodents were screened for these pathogens: while none was positive for Rickettsia spp.; five rodent spleens were PCR-positive for Bartonella spp.. Herein, we show the detection of potential novel variants of Bartonella sp. and Rickettsia sp. in fleas collected of wild rodents from Southern Brazil. Further studies are needed to fully characterize these microorganisms, as well as to improve the knowledge on the potential role of Neotropical flea species as diseases vectors.

Molecular and morphologic characterization of Sarcocystis felis (Apicomplexa: Sarcocystidae) in South American wild felids from Brazil.

Wild felids are thought to share parasites with domestic cats. However, little is known of the coccidian parasites of wild felids. We investigated the presence of Sarcocystis spp. in tissues of 6 species of 90 Neotropical small felids killed in road accidents in the state of Rio Grande do Sul, Brazil by using microscopic and molecular techniques. Formalin-fixed tissues from 28 felids were examined, and Sarcocystis felis-like sarcocysts were detected in 4 wild cats (2 Puma yagouaroundi and 2 Leopardus guttulus). By transmission electron microscopy, sarcocysts from a P. yagouaroundi were identical to S. felis from domestic cats in the USA. Direct sequencing of PCR amplicons resulted the unambiguous sequences of the ITS-1 region from 18 of the 31 PCR positive wild cats; 5 sequences from each P. yagouaroundi, and Leopardus geoffroyi, 4 sequences from L. guttulus, and 2 sequences from each Leopardus wiedii, and Leopardus colocolo. Sequences analysis of ITS-1 region revealed the highest identiy (97-99%) with that of previously describe isolates of S. felis from domestic cats in the USA and identified them as S. felis. Tissues of 1 Leopardus pardalis tested by PCR and histology were negative. The phylogenetic relationship indicated that S. felis is quite different to species which employ opossums as their definitive host. This is the first report of S. felis infection in small wild felids from Brazil.

Molecular phylogenetic position of endangered Wilfredomys within Sigmodontinae (Cricetidae) based on mitochondrial and nuclear DNA sequences and comments on Wiedomyini.

Wilfredomys, a monotypic genus of endangered sigmodontine rats, was historically related to the tribe Thomasomyini or considered "incertae sedis". Given no molecular data is available for Wilfredomys, the phylogenetic position of this taxon is uncertain in relation to modern, molecular hypotheses of sigmodontine relationships. We investigate the phylogeny of Wilfredomys to provide a hypothesis of its position within Sigmodontinae based on nuclear and mitochondrial DNA sequences. Bayesian and maximum likelihood phylogenetic analyses recovered Wilfredomys oenax as sister to Wiedomys pyrrhorhinos, and Wie. cerradensis fell out sister to this clade. At the genus level, Phaenomys is sister to Wilfredomys + Wiedomys, forming a novel and well-supported sigmodontine clade. Our results suggest that tribe Wiedomyini should encompass Wilfredomys in addition to Wiedomys and Cholomys, thus the hypothesis that Wiedomys is paraphyletic should be investigated further. Another plausible classification scheme consistent with our results would be to expand Wiedomyini to encompass the clade composed of Phaenomys + Wilfredomys + Wiedomys. Last, our recovery of an "Atlantic clade" composed of lineages restricted to eastern South America supports the idea that this region has likely played an important role in sigmodontine diversification.

Pequenos mamíferos não-voadores (Didelphimorphia, Rodentia) em dois fragmentos de mata de restinga de Rio Grande, planície costeira do Rio Grande do Sul / Non-volant small mammals ((Didelphimorphia, Rodentia) in two forest fragments in Rio Grande, Rio Grande do Sul coastal plain, Brazil

As matas de restinga representam formações vegetais originais na Planície Costeira do estado do Rio Grande do Sul. O objetivo deste trabalho foi avaliar a composição de espécies de pequenos mamíferos não-voadores em dois fragmentos de matas de restinga (mata palustre e mata arenosa ciliar) no município de Rio Grande, região sul da Planície Costeira do Rio Grande do Sul. Um total de 234 indivíduos pertencentes a três espécies de marsupiais (Didelphidae: Cryptonanus guahybae, Didelphis albiventris, Lutreolina crassicaudata) e oito espécies de roedores (Cricetidae: Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, O. nigripes, Oxymycterus nasutus, Scapteromys tumidus; Muridae: Mus musculus, Rattus rattus) foi capturado. As espécies C. guahybae, D. albiventris, D. kempi, H. brasiliensis, O. nigripes, S. tumidus e M. musculus foram registradas no fragmento de mata palustre, enquanto que C. guahybae, D. albiventris, Lutreolina crassicaudata, D. kempi, O. flavescens, O. nigripes, S. tumidus e R. rattus ocorreram no fragmento de mata arenosa ciliar. Oligoryzomys nigripes e S. tumidus foram as espécies mais abundantes no fragmento de mata palustre, representando respectivamente 40,4 e 22,1% do total de indivíduos capturados. No fragmento de mata arenosa ciliar, as espécies mais abundantes foram O. nigripes e D. albiventris, representando respectivamente 63,4 e 12,4% do total de indivíduos capturados. Indivíduos de C. guahybae e O. nigripes foram capturados em estrato arbóreo (alturas entre 0,50 e 1,65 m) enquanto que todos os indivíduos das demais espécies foram capturados no solo.

The restinga forests represent original vegetal formations in Coastal Plain of Rio Grande do Sul state. This work aimed to evaluate the species composition of non-volant small mammals in two restinga forests (peat forest and sandy riparian forest) in Rio Grande, Southern Rio Grande do Sul Coastal Plain. A total of 234 individuals belonging to three species of marsupials (Didelphidae: Cryptonanus guahybae, Didelphis albiventris, Lutreolina crassicaudata) and eight species of rodents (Cricetidae: Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, O. nigripes, Oxymycterus nasutus, Scapteromys tumidus; Muridae: Mus musculus, Rattus rattus) was captured. The species C. guahybae, D. albiventris, D. kempi, H. brasiliensis, O. nigripes, S. tumidus and M. musculus were recorded in the peat forest while C. guahybae, D. albiventris, Lutreolina crassicaudata, D. kempi, O. flavescens, O. nigripes, S. tumidus and R. rattus occurred in the riparian sandy forest. Oligoryzomys nigripes and S. tumidus were the most abundant species in the peat forest, representing 40.4 and 22.1% of the total of captured individuals, respectively. The most abundant species in the riparian sandy forest were O. nigripes e D. albiventris, representing 63.4 and 12.4% of the total of captured individuals. Individuals of C. guahybae and O. nigripes were captured on trees (heights between 0.50 and 1.65 m) while all individuals of the remaining species were captured on the ground.

Identificação de marsupiais do Rio Grande do Sul através da microestrutura dos pelos-guarda / Identification of marsupials from southern Brazil using microstructure of guard-hairs

A análise dos padrões microscópicos de pelos de mamíferos é uma técnica não-invasiva que pode auxiliar na identificação dos marsupiais brasileiros. O objetivo deste trabalho foi identificar padrões microscópicos dos pelos-guarda (cutícula e medula) de marsupiais ocorrentes no Rio Grande do Sul (RS), propondo uma chave dicotômica para sua identificação a partir dessas estruturas. Além disso, nós apresentamos, com detalhes, os padrões tricológicos de espécimes do gênero Monodelphis, um gênero ainda taxonomicamente obscuro que requer revisão no RS. Obtivemos o material analisado por meio da coleta de pelos de marsupiais capturados em campo ou provenientes de coleções de diferentes instituições. Identificamos os padrões dos pelos de dez espécies de marsupiais: Caluromys lanatus, Chironectes minimus, Didelphis aurita, Didelphis albiventris, Cryptonanus guahybae, Gracilinanus agilis, Gracilinanus microtarsus, Lutreolina crassicaudata, Micoureus paraguayanus e Philander frenatus. Os indivíduos do gênero Monodelphis foram analisados em conjunto, como parte do grupo dimidiata. Encontramos três padrões dentro desse grupo, sugerindo que possa haver uma terceira espécie além das duas normalmente reconhecidas (M. brevicaudis e M. dimidiata). A análise dos padrões microscópicos dos pelos possibilitou a identificação, com sucesso, da grande maioria das espécies à que pertencem os marsupiais do Rio Grande do Sul. Os resultados obtidos sugerem que as duas espécies de Monodelphis grupo dimidiata possam ocorrer com uma distribuição distinta no estado, estando uma presente principalmente na porção norte e a outra na porção leste do RS, com sobreposição na região central.

The analysis of mammalian hairs is a non-invasive technique that may help in the identification of Brazilian marsupials. Our objective was to identify microscopic patterns of marsupial guard-hairs (cuticle and medulla) from species with occurrence in the state of Rio Grande do Sul, southern Brazil. We also present a hair-based identification key for this group. Specifically for Monodelphis, a still taxonomically obscure genus that needs revision, we present detailed description of observed hair patterns. We obtained the analyzed material by collecting hair samples of marsupials captured in field or else deposited in different zoological collections. We identified hair patterns of ten marsupial species: Caluromys lanatus, Chironectes minimus, Didelphis aurita, Didelphis albiventris, Cryptonanus guahybae, Gracilinanus agilis, Gracilinanus microtarsus, Lutreolina crassicaudata, Micoureus paraguayanus and Philander frenatus. Individuals of the Monodelphis genus were analyzed together, considered as part of the dimidiata group. We found three distinct patterns for this group, suggesting the possible occurrence of a third species besides the two already recognized (M. brevicaudis and M. dimidiata). These morphs show distinct distribution in the state, with some degree of distribution overlap. The analysis of microscopic patterns of mammal hairs allowed the successful identification of the great majority of marsupials that occur in the Rio Grande do Sul state. Our results suggest that the two Monodelphis species of the dimidiata group might occur with a distinct distribution in the state, one of them occupying mainly the northern part and the other one the eastern region, with some overlap in the central part of the state.

Karyology of the Atlantic forest rodent Juliomys (Cricetidae): A new karyotype from southern Brazil.

Juliomys is a small rodent from the family Cricetidae which inhabits the Atlantic forest and forests from Argentina to eastern Brazil. The three species recognized so far have different karyotypes. In this paper, we describe a new karyotype with 2n = 32, FN = 48 found in Juliomys specimens from a high-altitude area in the Atlantic forest of southern Brazil. The karyotype was analyzed after G- and C-banding and silver staining of the nucleolus organizer regions (Ag-NOR) and its G-banding patterns were compared with those of the newly described species Juliomys ossitenuis (2n = 20, FN = 36). The 2n = 32 karyomorph presented peculiar features and was very different from those of the other species of the genus: J. pictipes (2n = 36, FN = 34), J. rimofrons (2n = 20, FN = 34) and J. ossitenuis (2n = 20, FN = 36). Differences were mostly due to centric and tandem fusions, pericentric inversion and loss of heterochromatin. The karyotype represents a powerful tool to differentiate Juliomys species and our data suggest that the karyotype described herein belongs to a new species.

Karyology of the Atlantic forest rodent Juliomys (Cricetidae): a new karyotype from southern Brazil

Juliomys is a small rodent from the family Cricetidae which inhabits the Atlantic forest and forests from Argentina to eastern Brazil. The three species recognized so far have different karyotypes. In this paper, we describe a new karyotype with 2n = 32, FN = 48 found in Juliomys specimens from a high-altitude area in the Atlantic forest of southern Brazil. The karyotype was analyzed after G- and C-banding and silver staining of the nucleolus organizer regions (Ag-NOR) and its G-banding patterns were compared with those of the newly described species Juliomys ossitenuis (2n = 20, FN = 36). The 2n = 32 karyomorph presented peculiar features and was very different from those of the other species of the genus: J. pictipes (2n = 36, FN = 34), J. rimofrons (2n = 20, FN = 34) and J. ossitenuis (2n = 20, FN = 36). Differences were mostly due to centric and tandem fusions, pericentric inversion and loss of heterochromatin. The karyotype represents a powerful tool to differentiate Juliomys species and our data suggest that the karyotype described herein belongs to a new species.

Multiple interstitial ribosomal sites (NORs) in the Brazilian squirrel Sciurus aestuans ingrami (Rodentia, Sciuridae) with 2n = 40: an overview of Sciurus cytogenetics

This is the first time the karyotype of the Brazilian squirrel Sciurusaestuans ingrami, with 2n = 40, is described. The karyotype of this species comprises 18 pairs of biarmed and one minute pair of acrocentric autosomes, a medium-sized submetacentric X and a medium-sized acrocentric Y. Four pairs have an interstitial secondary constriction, co-located with nucleolar organizer regions (NORs), identified by silver-staining technique and fluorescent in situ hybridization (FISH) with ribosomal 18S/28S probes. The occurrence of multiple interstitial NORs is rare in rodents, and this is one of the few examples, identified by a molecular cytogenetics approach