Circulation of picobirnavirus in Neotropical free-ranging mammals.

Picobirnavirus (PBV) is a family of non-enveloped double-stranded RNA viruses with bisegmented genomes. Segment 1 encodes the capsid protein and segment 2 encodes RNA-dependent RNA polymerase. They exhibit high genomic heterogeneity and infect a wide range of vertebrate hosts, including humans. The objective of this study was to expand our knowledge of the circulation of PBV in free-living animals from two regions (Brazil and Argentina) of the Atlantic Forest. Fecal samples were analyzed from free-living animals: tapir, brocket deer, peccary, and different species of rodents and marsupials. A total of 133 samples were collected and analyzed by RT-PCR, of which 44 (33.08%) were PBV-positive. Nine amplicons were sequenced, five species from Argentina and four from Brazil, and phylogenetic analysis was performed. The nucleotide and amino acid identities of the PBV strains detected in animals from Argentina and Brazil were between 66.3% and 82.5% and between 55.3% and 74.2%, respectively. The analysed strains presented conserved nucleotide blocks without distinction of the host species. The phylogenetic tree showed that PBV strains from Atlantic Forest animals belonging to genogroup I were grouped into different clusters, without defining groups according to host species (human or animal) or the geographical area of detection. This is the first study on PBV in free-living animals in the Atlantic Forest. Our analysis suggested that PBV strains can infect different animal species, leading to PBV transmission between animals and humans. This reinforces the hypothesis of previous crossover points in the ecology and evolution of heterologous PBV strains.

Penile shape discriminates two cryptic species of Akodon Meyen, 1833 (Mammalia, Rodentia, Cricetidae) from eastern Brazil.

Glans penis morphology has been used as a powerful tool in mammal taxonomy to differentiate cryptic species. Neotropical rodent species Akodoncursor and A.montensis are cryptic, and interspecific hybrids are like their parental species. We investigated non-metric and metric phallic characters aiming to differentiate A.cursor from A.montensis. We also evaluated the parental species' influence of the phallic characters on hybrids. We analysed 96 male adults-56 A.cursor, 27 A.montensis, and 13 hybrids, subgrouping species by locality and hybrids by parental species (paternal vs maternal). We verified that A.cursor and A.montensis are distinguishable by penile-shape morphology: A.cursor has an elongated penile form with a flare in the distal portion and A.montensis has a barrel-shaped form. Also, dark spots in ventral view, if present in A.montensis, distinguish A.montensis from A.cursor. Although the non-metric characters differentiate the species, they do not distinguish the subgroups of A.cursor, A.montensis, and hybrids. The metric phallic characters indicated a significant difference between species and hybrids. These characters also differentiate the population groups of A.cursor. However, A.montensis subgroups and hybrids subgroups did not present a significant difference. This study shows the importance of penis morphology in the taxonomy of the cryptic rodent species A.cursor and A.montensis, representing a powerful tool to discriminate male specimens in mammal collections without karyotyping or sequencing, even though the specimens occurred in sympatric areas. Since most taxidermy protocols do not preserve the penis in mammal preparations, liquid preservation of some specimens or the removal of the penis before taxidermy for liquid preservation could be beneficial. We also recommend the organisation in museum collections of a penis bank for the A.cursor species group (or even all rodent species) to avoid losing this important information for species identification.

Karyotypes of Brazilian non-volant small mammals (Didelphidae and Rodentia): An online tool for accessing the chromosomal diversity.

We have created a database system named CIPEMAB (CItogenética dos PEquenos MAmíferos Brasileiros) to assemble images of the chromosomes of Brazilian small mammals (Rodents and Marsupials). It includes karyotype information, such as diploid number, karyotype features, idiograms, and sexual chromosomes characteristics. CIPEMAB facilitates quick sharing of information on chromosome research among cytogeneticists as well as researchers in other fields. The database contains more than 300 microscopic images, including karyotypic images obtained from 182 species of small mammals from the literature. Researchers can browse the contents of the database online (http://www.citogenetica.ufes.br). The system enables users to locate images of interest by taxa, and to display the document with detailed information on species names, authors, year of the species publication, and karyotypes pictures in different colorations. CIPEMAB has a wide range of applications, such as comparing various karyotypes of Brazilian species and identifying manuscripts of interest.

The imagos of some enigmatic members of the Hermanella complex (Ephemeroptera, Leptophlebiidae).

The imago stages of three species of the Hermanella complex are described mostly based on material from Roraima, northern Brazil: Hydrosmilodon gilliesae, Hydromastodon sallesi and Leentvaaria palpalis. Male imagos of Hydrosmilodon gilliesae and Leentvaaria palpalis both have a pair of large, broad projections at the posterior margin of the styliger plate, nearly covering the penis lobes; in Leentvaaria palpalis, however, these projections are fused. The male imago of Hydromastodon sallesi resembles Hydrosmilodon plagatus in that both species have a styliger plate with a robust projection that is curved towards the penis lobes. DNA barcoding is likely to be a powerful investigative tool for identifying and understanding species limits among these Ephemeroptera taxa, especially if it is used within an integrative taxonomic context. An updated identification key to the genera of the Hermanella complex is proposed.

Stage description, new combination and new records of Neotropical Brachycercinae (Ephemeroptera: Caenidae).

We present taxonomic contributions and new records for Neotropical Brachycercinae based on material from Brazil. We performed a phylogenetic analysis in order to test the relationship between Alloretochus Sun & McCafferty, 2008 and Latineosus Sun & Mc- Cafferty, 2008, and Alloretochus sigillatus was recovered in the Latineosus clade. Therefore, we propose a new combination, Latineosus sigillatus comb. n. The nymph of Latineosus sigillatus is described and is associated with imago through molecular tools. Moreover, Alloretochus peruanicus (Soldán, 1986) is reported for the first time from Brazil.

Neotropical forest expansion during the last glacial period challenges refuge hypothesis.

The forest refuge hypothesis (FRH) has long been a paradigm for explaining the extreme biological diversity of tropical forests. According to this hypothesis, forest retraction and fragmentation during glacial periods would have promoted reproductive isolation and consequently speciation in forest patches (ecological refuges) surrounded by open habitats. The recent use of paleoclimatic models of species and habitat distributions revitalized the FRH, not by considering refuges as the main drivers of allopatric speciation, but instead by suggesting that high contemporary diversity is associated with historically stable forest areas. However, the role of the emerged continental shelf on the Atlantic Forest biodiversity hotspot of eastern South America during glacial periods has been ignored in the literature. Here, we combined results of species distribution models with coalescent simulations based on DNA sequences to explore the congruence between scenarios of forest dynamics through time and the genetic structure of mammal species cooccurring in the central region of the Atlantic Forest. Contrary to the FRH predictions, we found more fragmentation of suitable habitats during the last interglacial (LIG) and the present than in the last glacial maximum (LGM), probably due to topography. We also detected expansion of suitable climatic conditions onto the emerged continental shelf during the LGM, which would have allowed forests and forest-adapted species to expand. The interplay of sea level and land distribution must have been crucial in the biogeographic history of the Atlantic Forest, and forest refuges played only a minor role, if any, in this biodiversity hotspot during glacial periods.

Gastrointestinal morphological alterations in obese rats kept under hypercaloric diets.

Hypercaloric diets have been successfully used as experimental models of obesity. This work compared morphological characteristics of inferior gastrointestinal organs. The experiment lasted 10 weeks, during which the rats' food consumption, body weight, distance between the mouth and neck, distance between mouth and neck, distance between neck and tail, and abdominal circumference were evaluated weekly. After the sacrifice of the rats, 20 variables referring to inferior gastrointestinal morphology were assessed. The results comprised descriptive statistics of the data, analysis of main components, linear correlation, and t-tests. Significant differences were found between the two groups for the variables of abdominal circumference, retroperitoneal fat, ratio between retroperitoneal fat/animal weight, stomach weight, ratio between animal weight/intestine weight and mesentery/animal weight, length of small intestine, length of large intestine, and lateral line of the cecum. The data allow us to state that a hypercaloric diet can be responsible an increase in fat in the abdominal cavity as well as gastrointestinal morphological alterations, principally in stomach development.

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.

Karyological geographic variation of Oligoryzomys nigripes Olfers, 1818 (Rodentia, Cricetidae) from Brazil

The karyotypes of 85 specimens of Oligoryzomys nigripes (Rodentia, Sigmodontinae) collected in the Cerrado and Atlantic Forest of seven states of Brazil were analyzed. Eighty four specimens presented a karyotype with 2n = 62 and one individual had 2n = 61 due to a monosomy of the X chromosome. High levels of intra- and inter-population karyotypic variability, due to sex chromosomes heteromorphisms and pericentric inversions in four autosomes (pairs 2, 3, 4 and 8), led to a variation of the autosomal arm numbers (fundamental number, FN) from 78 to 82. Synaptonemal complex analyses revealed normal meiosis in males heterozygous for pericentric inversions. We found 39 different cytotypes, 27 of which are herein described for the first time. A literature survey revealed 46 described karyotypes for O. nigripes. We tested the hypothesis that chromosomal variants frequencies are dependent on geographical distribution and we propose a model for the karyotypical evolution of Oligoryzomys nigripes with 2n = 62/FN = 78-82.