Dentes supranumerários em Necromys lasiurus (Rodentia, Cricetidae): primeiro registro em Sigmodontinae

There are several kinds of anomalies related to the teeth reported in mammals, and one of them is known as supernumerary teeth and is commonly noticed in the literature, being reported in nearly all orders of mammals. Here, we report the occurrence of supernumerary molars in the sigmodontine rodent Necromys lasiurus, a common and widespread small rodent of tribe Akodontini. In order to assess the patterns of morphometric variation of N. lasiurus in eastern South America, we examined the skulls of 1763 specimens. The supernumerary molars were found in 2 individuals, which represent a frequency of 0.11%. The origin of supernumerary teeth started a long discussion on tooth homology, whether this anomaly is a result of heredity, a mutation or an atavism. Based on the morphologies presented by the extra teeth encountered in N. lasiurus and on the evidences and hypothesis available in the literature, we consider that the presence of these supernumerary molars in one of the studied animals could be considered an atavism, and we also consider the extra molar presented by the other specimen is a malformation, due to some kind of random process occurred in later stages of the development of distal dental gem. To the best of our knowledge, this represents the first record of supernumerary molars in the subfamily Sigmodontinae and one of the few known cases in rodents.Diversos tipos de anomalias dentárias já foram descritas para mamíferos e uma delas é conhecida como dente supranumerário comumente reportada na literatura para quase todas as ordens de mamíferos. No presente trabalho apresentamos a ocorrência de molares extras em Necromys lasiurus, uma espécie de pequeno roedor sigmodontíneo comum e amplamente distribuído, membro da tribo Akodontini. Durante o levantamento de dados para avaliação morfométrica da variação da espécie no leste da América do Sul, foram examinados os crânios de 1763 espécimes. Os dentes supranumerários foram encontrados em dois indivíduos, representando 0.11% da amostra investigada. A ocorrência dos dentes supranumerários há muito tempo levanta questões acerca da homologia dentária, das mutações e dos atavismos que podem estar relacionados à origem desta anomalia. Baseados na morfologia apresentada pelos molares extra numerários de N. lasiurus, nós consideramos que a presença dos mesmos em um dos espécimes é um atavismo, e no outro, trata-se de uma malformação devido a um processo de origem tardia no desenvolvimento das gemas dentárias. Com base em nosso conhecimento de outras espécies e em toda a revisão bibliográfica, a ocorrência dos dentes supranumerários em N. lasiurus trata-se dos primeiros registros da anomalia para a subfamília Sigmodontinae e um dos poucos já registrados para a ordem Rodentia.Fil: Simoes Libardi, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz Esalq; BrasilFil: Reis Percequillo, Alexandre. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz Esalq; Brasi

Age and habitat quality matters: isotopic variation of two sympatric species of rodents in Neotropical Forest

Dietary studies allow us to understand important ecological patterns such as intra- and interpopulation variation and interspecific differences regarding the use of food sources. Stable isotopes have been successfully employed to detect dietary differences between species and feeding shifts within a species, as a response to age, habitat use, and resource availability. Here we investigated the stable isotope compositions of carbon and nitrogen of young and adult specimens of Euryoryzomys russatus and Sooretamys angouya and their stomach contents, in a complex mosaic of vegetation in the Brazilian Atlantic Forest. Isotopes indicated a pronounced inter- and intraspecific plasticity in resource use for E. russatus and S. angouya. Plant sources were the prevalent feeding items for E. russatus, with low to intermediate consumption of arthropods. For S. angouya, plants were dominant in the stomach content, but arthropod arose as an important source. E. russatus showed more variation in isotopic signature between grids than S. angouya, suggesting that the former was more affected by habitat changes. These results allow us to better understand the ontogeny, diet and the behavioral responses to environmental variations of both species. Finally, our study contributes to reduce the lack of knowledge about sympatric species ecology and aggregates information for their conservation.Fil: Bovendorp, Ricardo Siqueira. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Universidade Estadual Paulista “Júlio de Mesquita Filho”; BrasilFil: Simoes Libardi, Gustavo. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Sarmento, Mariana Montagner de Moraes. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Camargo, Plínio Barbosa. Universidade de Sao Paulo; BrasilFil: Reis Percequillo, Alexandre. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasi

Small mammals of the Estação Ecológica de Bananal, southeastern Atlantic Forest, Brazil, with description of a new species of Brucepattersonius (Rodentia, Sigmodontinae)

The Atlantic Forest harbors an impressive diversity of nonvolant small mammals. Despite having been the target of many ecological and taxonomical studies in the last decades, this group is still poorly known in several aspects – basic information on intrapopulational morphologic variation and proper diagnoses are lacking for many species, even for common taxa. This is related to the fact that large series of specimens from a single locality are extremely rare in scientific collections. A consistent sampling effort was conducted at Estação Ecológica de Bananal, northeastern São Paulo State, throughout seven field expeditions between 2003 and 2011, under the coordination of the Museu de Zoologia da Universidade de São Paulo, resulting in extensive series of nonvolant small mammals. We studied in detail the external and cranio-dental morphology of this sample (575 specimens), that we assigned to 31 known species besides one new species to science. Most species belong to order Rodentia (26 species) from the families Cricetidae (22 species) and Echimyidae (four species); the remaining (six species) are marsupials from the order Didelphimorphia, family Didelphidae. This is one of the most diverse assemblages ever recorded in this biome, and includes some of the rarest endemic rodents of the Atlantic Forest, such as Abrawayaomys ruschii, Blarinomys breviceps, Drymoreomys albimaculatus, Phaenomys ferrugineus, Phyllomys kerri and Rhagomys rufescens. This outstanding richness can be explained by the extensive sampling effort performed for a long period of time. Also, the capture success of the third expedition (8.25%) is among the highest rates obtained in the Atlantic Forest and the extensive use of pitfall traps was fundamental for trapping this high number of species. Herein, we provide an annotated list of nonvolant small mammals occurring at Estação Ecológica de Bananal, with comprehensive analyses of morphological variation and detailed diagnoses that will allow their proper identification, and will provide a sound basis for a better comprehension of the geographic variation of these taxa across the biome. We also present a formal description for a new species of Brucepattersonius from the mountain ranges along the Paraíba do Sul valley. For five species of sigmodontine rodents, we investigate the levels of ontogenetic and sexual variation, and while the first is accentuate in all analyzed species the second does not contribute significantly to intrapopulation variation

Geographic variation in a South American clade of mormoopid bats, Pteronotus (Phyllodia), with description of a new species

The subgenus Phyllodia (genus Pteronotus) comprises 9 species ranging from the western coast of Mexico to central Brazil, including Greater and Lesser Antilles. Two of them, Pteronotus rubiginosus and Pteronotus sp. 1, form an endemic South American clade within Phyllodia and are reported in sympatry for several localities in Guyana, Suriname, French Guiana, and northern Brazil. We herein performed a comprehensive investigation to fully characterize the cranial variation and genetic intraspecific structuring within this clade. We also integrated genetic, morphological, and acoustic evidence to formally describe the species previously reported as Pteronotus sp. 1. Specimens of P. rubiginosus occurring in sympatry with the new species have a more distinctive cranial phenotype than those from allopatric areas, suggesting character displacement as a potential force promoting divergence by decreasing resource competition or reproductive interactions between them. Although the 2 species are sympatric in several localities, the divergence in their echolocation calls also may be promoting resource partitioning at the microhabitat level, with P. rubiginosus foraging in less cluttered areas and the new species restricted to more cluttered areas. © 2018 American Society of Mammalogists, www.mammalogy.org

A new genus of oryzomyine rodents (Cricetidae, Sigmodontinae) with three new species from montane cloud forests, western Andean cordillera of Colombia and Ecuador

The Andean cloud forests of western Colombia and Ecuador are home to several endemic mammals; members of the Oryzomyini, the largest Sigmodontinae tribe, are extensively represented in the region. However, our knowledge about this diversity is still incomplete, as evidenced by several new taxa that have been described in recent years. Extensive field work in two protected areas enclosing remnants of Chocó montane forest recovered a high diversity of small mammals. Among them, a medium-sized oryzomyine is here described as a new genus having at least three new species, two of them are named and diagnosed. Although externally similar to members of the genera Nephelomys and Tanyuromys, the new genus has a unique molar pattern within the tribe, being characterized by a noticeable degree of hypsodonty, simplification, lamination, and third molar compression. A phylogeny based on a combination of molecular markers, including nuclear and mitochondrial genes, and morphological data recovered the new genus as sister to Mindomys, and sequentially to Nephelomys. The new genus seems to be another example of a sigmodontine rodent unique to the Chocó biogeographic region. Its type species inhabits cloud forest between 1,600 and 2,300 m in northernmost Ecuador (Carchi Province); a second species is restricted to lower montane forest, 1,200 m, in northern Ecuador (Imbabura Province); a third putative species, here highlighted exclusively by molecular evidence from one immature specimen, is recorded in the montane forest of Reserva Otonga, northern Ecuador (Cotopaxi Province). Finally, the new genus is also recorded in southernmost Colombia (Nariño Department), probably represented there also by a new species. These species are spatially separated by deep river canyons through Andean forests, resulting in marked environmental discontinuities. Unfortunately, Colombian and Ecuadorian Pacific cloud forests are under rapid anthropic transformation. Although the populations of the type species are moderately abundant and occur in protected areas, the other two persist in threatened forest fragments.Fil: Brito, Jorge. Instituto Nacional de Biodiversidad; EcuadorFil: Koch, Claudia. Zoologisches Forschungsmuseum Alexander Koenig.; AlemaniaFil: Reis Percequillo, Alexandre. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Tinoco, Nicolás. Pontificia Universidad Católica del Ecuador; EcuadorFil: Weksler, Marcelo. Universidade Federal do Rio de Janeiro; BrasilFil: Pinto, C. Miguel. Observatorio de Biodiversidad Ambiente y Salud; EcuadorFil: Pardiñas, Ulises Francisco J.. Instituto Nacional de Biodiversidad; Ecuador. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; Argentin

Diversidade de mamíferos do baixo Rio Jufari, Roraima, Brasil

Faunal inventories are essential to directly access the diversity of a region. Although the Amazon rainforest exhibit large estimates of mammal species richness, the region still exhibits large sampling gaps. Aiming to fill a sampling gap on the mammalian diversity in the Brazilian Amazon rainforest, we conducted an inventory of non-volant mammals at “terra firme” forest near the mouth of Rio Jufari, an affluent of north bank of Rio Negro, near its confluence with Rio Branco. To sample small mammals, we applied a total effort of 3,673 live trap nights, and 2,700 pitfall trap nights. For large mammals we performed unstandardized line transect census, and included, as well, records from occasional encounters and material donated by Caicubi community members. The pitfall traps proved to be extremely valuable for the small mammals sampling. We observed a low mammalian diversity when compared to other inventories throughout the Amazon basin. We recorded 27 species belonging to 25 genera, 16 families and nine orders of the Class Mammalia. The majority of recorded species is known from Guianan subregion. However, we present: extension on the known distribution records for Marmosops bishopi; taxonomic comments on the marsupial Monodelphis brevicaudata; and new collection record for species of the genera Oecomys and Makalata. It is remarkable the extremely low number of species from the order Primates. Data based on interviews suggested that this small number of primate specimens is historical, and areas closer to Rio Negro and Rio Branco exhibit higher diversity. Our samples showed that Rio Negro-Rio Branco confluence do not present an endemic mammalian fauna, once the region shares its mammalian composition with other confluence areas in the Amazon basin, especially with those on the northeastern Amazon region

Atlantic mammal traits: a dataset of morphological traits of mammals in the atlantic forest of south America

Measures of traits are the basis of functional biological diversity. Numerous works consider mean species-level measures of traits while ignoring individual variance within species. However, there is a large amount of variation within species and it is increasingly apparent that it is important to consider trait variation not only between species, but also within species. Mammals are an interesting group for investigating trait-based approaches because they play diverse and important ecological functions (e.g., pollination, seed dispersal, predation, grazing) that are correlated with functional traits. Here we compile a data set comprising morphological and life history information of 279 mammal species from 39,850 individuals of 388 populations ranging from −5.83 to −29.75 decimal degrees of latitude and −34.82 to −56.73 decimal degrees of longitude in the Atlantic forest of South America. We present trait information from 16,840 individuals of 181 species of non-volant mammals (Rodentia, Didelphimorphia, Carnivora, Primates, Cingulata, Artiodactyla, Pilosa, Lagomorpha, Perissodactyla) and from 23,010 individuals of 98 species of volant mammals (Chiroptera). The traits reported include body mass, age, sex, reproductive stage, as well as the geographic coordinates of sampling for all taxa. Moreover, we gathered information on forearm length for bats and body length and tail length for rodents and marsupials. No copyright restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data.Fil: Gonçalves, Fernando. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Bovendorp, Ricardo S.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Beca, Gabrielle. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Bello, Carolina. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Costa Pereira, Raul. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Muylaert, Renata L.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Rodarte, Raisa R.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Villar, Nacho. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Souza, Rafael. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Graipel, Maurício E.. Universidade Federal de Santa Catarina; BrasilFil: Cherem, Jorge J.. Caipora Cooperativa, Florianopolis; BrasilFil: Faria, Deborah. Universidade Estadual de Santa Cruz; BrasilFil: Baumgarten, Julio. Universidade Estadual de Santa Cruz; BrasilFil: Alvarez, Martín R.. Universidade Estadual de Santa Cruz; BrasilFil: Vieira, Emerson M.. Universidade do Brasília; BrasilFil: Cáceres, Nilton. Universidade Federal de Santa María. Santa María; BrasilFil: Pardini, Renata. Universidade de Sao Paulo; BrasilFil: Leite, Yuri L. R.. Universidade Federal do Espírito Santo; BrasilFil: Costa, Leonora Pires. Universidade Federal do Espírito Santo; BrasilFil: Mello, Marco Aurelio Ribeiro. Universidade Federal de Minas Gerais; BrasilFil: Fischer, Erich. Universidade Federal do Mato Grosso do Sul; BrasilFil: Passos, Fernando C.. Universidade Federal do Paraná; BrasilFil: Varzinczak, Luiz H.. Universidade Federal do Paraná; BrasilFil: Prevedello, Jayme A.. Universidade do Estado de Rio do Janeiro; BrasilFil: Cruz-Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Carvalho, Fernando. Universidade do Extremo Sul Catarinense; BrasilFil: Reis Percequillo, Alexandre. Universidade de Sao Paulo; BrasilFil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Duarte, José M. B.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil. Fundación Oswaldo Cruz; BrasilFil: Bernard, Enrico. Universidade Federal de Pernambuco; BrasilFil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Lamattina, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Ministerio de Salud de la Nación; ArgentinaFil: Vanderhoeven, Ezequiel Andres. Ministerio de Salud de la Nación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentin

Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species