Marcus Vinicius Brandão

On the occurrence of Holochilus chacarius (Cricetidae: Sigmodontinae) in Brazil, with taxonomic notes on Holochilus species

Quatro especies de Holochilus (Cricetidae: Sigmodontinae) sao atualmente reconhecidas. De acordo com a literatura, tres especies sao registradas para o Brasil: H. brasiliensis, H. chacarius e H. sciureus. Amostras provenientes do oeste do Brasil (Estados do Mato Grosso e Mato Grosso do Sul) sao geralmente reportadas como H. sciureus e, quando referentes a especimes do Pantanal, como H. chacarius. Entretanto, o estado taxonomico de especimes dessa regiao ainda nao foi propriamente avaliado atraves de analise morfologica detalhada e/ou especimes testemunho. Cerca de 110 especimes de Holochilus depositados em colecoes brasileiras foram analisados qualitativa e quantitativamente (testes univariados e multivariados). Nossos resultados suportam a existencia de tres especies (H. sciureus, H. brasiliensis e H. chacarius) no pais, as quais possuem diferencas morfologicas e morfometricas significativas entre si, assim confirmando que as amostras do Mato Grosso e Mato Grosso do Sul, outrora erroneamente identificados como H. sciureus, pertencem a H. chacarius. Esta especie difere de H. sciureus e H. brasiliensis por apresentar uma serie de caracteristicas da pelagem e do crânio, tais como: coloracao da pelagem castanho claro no dorso, levemente alaranjada nas laterais e branca no ventre; crista masseterica confluente ao nivel ou ligeiramente acima do forame mental e na parte anterior do m1; principais cuspides molares alternadas; lofideos compactados e com margens externas agudas (raramente prismatica), fossetideo anteromediano labialmente deslocado e subcircular (pequeno a medio); metaflexideo menos desenvolvido (muitas vezes nao atingindo a linha mediana do dente); protoconideo e hipoconideo subrectangulares e transversalmente orientados; mesoflexideo transversalmente orientado e mesolofo ausente. A distribuicao geografica atualizada de Holochilus no Brasil indica que H. sciureus esta presente na porcao norte do pais, sendo a unica especie presente na Amazonia e na Caatinga e seu limite no Cerrado ocorre no centro de Goias. Holochilus brasiliensis esta restrito ao leste do Brasil, sendo seu limite norte na Mata Atlântica do sul da Bahia. Holochilus chacarius esta presente nas areas do Pantanal do Mato Grosso e Mato Grosso do Sul. Um novo registro estende a distribuicao de H. chacarius para a porcao de Cerrado no leste do Mato Grosso, comprovando sua presenca neste bioma.

The genus Abrawayaomys Cunha and Cruz, 1979 (Rodentia: Cricetidae: Sigmodontinae): geographic variation and species definition

Abrawayaomys is a genus endemic to the Atlantic Forest with unique craniodental attributes within the radiation of sigmodontine rodents. Recent data hypothesized the existence of 2 species of Abrawayaomys, namely A. ruschii (from the Brazilian states of Espírito Santo, Rio de Janeiro, and São Paulo) and A. chebezi (from the Argentinean province of Misiones and the Brazilian state of Paraná), as well as a possible undescribed species (from the Brazilian state of Minas Gerais). Herein, based on a large series of recently collected specimens, we assessed the congruence between morphologic and molecular characters to search for discontinuities on these features across geography to delimit species within the genus, testing the aforementioned hypothesis. Morphological analyses, both qualitative and quantitative, showed that all characters are polymorphic throughout the geographic range of the genus. Results from phylogenetic analyses of cytochrome b (Cytb) data showed the topology (Misiones (Minas Gerais (São Paulo, Rio de Janeiro))), which is better explained as geographic rather than taxonomic variation, based on low values of genetic divergence observed between all specimens. Therefore, we reject the hypothesis of a polytypic Abrawayaomys, synonymizing A. chebezi to A. ruschii, and do not recognize specimens from Minas Gerais state as representing a distinct species.

New records of Chironectes minimus (Zimmermann, 1870) (Didelphimorphia, Didelphidae) from central Brazil, with comments on its distribution pattern

Abstract Chironectes minimus is a marsupial with unique morphological and ecological characteristics. Owing mainly to its semi-aquatic habits, it is rarely collected by conventional methods, being consequently underrepresented in scientific collections. Its distribution in South America is currently considered disjunct, with a north-west and a south-east portion, and a large gap of more than one thousand kilometers that comprises central Amazonia and a large portion of the Cerrado. On the basis of four museum specimens and two photographed live animals, we present six new records for the species. These records extend the species’ distribution, showing that its range is continuous from southern Amazonia and through Cerrado gallery forests, to the southern portion of its range in southeastern South America. Most known records of C. minimus are from preserved riparian forests that usually present certain characteristics, such as fast-flowing water, stony substrate, and/or natural holes used as dens. Therefore, we hypothesize that the occurrence of this species is more closely related to well-preserved riparian forests containing these types of habitats than to the biomes themselves. Consequently, this species is probably found through most tropical and subtropical South American biomes that present the aforementioned habitat types. Therefore, the previous distributional gap of the species, now filled on its central-east portion, was probably a sampling artifact.

Range extension of Centronycetris maximiliani (Mammalia: Chiroptera) for southern Amazonia

Bat species of the genus Centronycteris are some of the rarest Neotropical Emballonuridae and fewer than 50 specimens have been deposited in scientific collections. The aim of this study is to extend the distribution of Centronycteris maximiliani. Three C. maximiliani specimens were recorded in the Brazilian Amazonia, providing the first record of the species for the state of Rondonia, the southernmost record of the species for the Amazon biome in Brazil, and an additional record for the state of Para. Although these new records of C. maximiliani reinforce the idea that this species is widely distributed throughout the Amazon biome, its low capture rate reflects the rarity of this species, since only three specimens were collected during three to four year field effort.

Range extension of Lundomys molitor (Winge, 1887) (Mammalia: Rodentia: Cricetidae) to eastern Rio Grande do Sul state, Brazil

The distribution range of Lundomys molitor , a cricetid rodent species known from only six localities, herein is extended about 295 km with the inclusion of a record from Rio Grande do Sul state. The new locality represents the easternmost limit of the distribution of this poorly studied species.

Rediscovery and range extension of the black-shouldered opossum Caluromysiops irrupta Sanborn, 1951 (Didelphimorphia, Didelphidae) in Brazil

Abstract Caluromysiops irrupta is a rare marsupial that inhabits the western part of the Amazon forest. It is an arboreal and nocturnal species, and its real distribution is yet to be investigated. Since its description by Sanborn in 1951, only eight records were reported from Peru, Colombia, and northwestern Brazil. In this work, we provide a new record for Mato Grosso state, Brazil, based on a specimen captured during a faunal rescue of vegetation suppression. This record represents the easternmost limit of the distribution of the black-shouldered opossum and the second known specimen from Brazil, extending its range about 718 km toward an area close to lands under intensive use and high rate of deforestation. The present record is an evidence of the potential of faunal rescues for generating data, which are useful for conservation and management purposes in the Neotropics.

The presence of Wilfredomys oenax (Rodentia: Cricetidae: Sigmodontinae) in São Paulo state, southeastern Brazil: a locally extinct species?

The Rufous-nosed Mouse Wilfredomys oenax is a rare Sigmodontinae rodent known from scarce records from northern Uruguay and south and southeastern Brazil. This species is underrepresented in scientific collections and is currently classified as threathened, being considered extinct at Curitiba, Parana, the only confirmed locality of the species at southeastern Brazil. Although specimens from Sao Paulo were already reported, the presence of this species in this state seems to have passed unnoticed in recent literature. Through detailed morphological analyzes of specimens cited in literature, the present work confirms and discusses the presence of this species in Sao Paulo state from a specimen collected more than 70 years ago. Recently, by the use of modern sampling methods, other rare Sigmodontinae rodents, such as Abrawayomys ruschii, Phaenomys ferrugineous and Rhagomys rufescens, have been recorded to Sao Paulo state. However, no specimen of Wilfredomys oenax has been recently reported indicating that this species might be locally extinct. The record mentioned here adds another species to the state of Sao Paulo mammal diversity and reinforces the urgency of studying Wilfredomys oenax.