Rogério Vieira Rossi

A Revision of the Didelphid Marsupial Genus Marmosa Part 1. The Species in Tate's ‘Mexicana’ and ‘Mitis’ Sections and Other Closely Related Forms

Abstract We revise the nominal species of mouse opossums currently synonymized with Marmosa mexicana Merriam, 1897, and M. robinsoni Bangs, 1898, which include all of the trans-Andean taxa currently assigned to the nominotypical subgenus of Marmosa. In addition, we redescribe two other species that appear to be closely related to M. mexicana and M. robinsoni based on morphological or molecular citeria: M. rubra Tate, 1931, and M. xerophila Handley and Gordon, 1979. Based on first-hand examination of holotypes and other material (about 1500 specimens in total), we additionally recognize M. isthmica Goldman, 1912, and M. simonsi Thomas, 1899 (both currently synonymized with M. robinsoni), and M. zeledoni Goldman, 1917 (currently synonymized with M. mexicana), as valid species. For each of the seven species recognized as valid herein (M. mexicana, M. zeledoni, M. isthmica, M. robinsoni, M. xerophila, M. simonsi, M. rubra), we describe and illustrate diagnostic external and craniodental characters, tabulate measurement data from adult specimens, list all known examples of sympatry, and map geographic ranges based on specimens examined. The species newly recognized as valid herein, all of which occur in Central America and/or northwestern South America, substantially increase the known diversity of trans-Andean mouse opossums, but it is not currently known whether or not these represent a distinct radiation within the genus Marmosa.

Checklist dos mamíferos do Estado de São Paulo, Brasil

Sao Paulo harbors 231 mammal species until now. This is an estimate of its real diversity since many regions of the State continue poorly surveyed, and also reflects the lack of taxonomic work for certain mammal taxa. Nevertheless, our knowledge of the Sao Paulo mammals has increased in 20% in the last 12 years, especially in relation to bats and rodents. These new data are based in mammal inventories and also in the analysis of specimens housed in scientific collections associated with taxonomic revisions. We also know better about the mammal distribution in the distinct vegetation units present in the State, permitting us to divide the mammals in three distinct components: the most important one is the generalists, represented by species occurring in every landscape in the State, while the second one concentrates species inhabiting the open formations, and the third component the species associated with the forest formations. Besides, the number of studies dealing with the effect of fragmentation and the permeability of mammals in altered areas also has increased. Occurrence, abundance and vulnerability data were essential to raise strategies in order to choose priority areas and to indicate priority actions to conserve the mammals of the State, as well as to classify the species in the different proposed threaten categories, culminating in the List of the Threaten Species of the Sao Paulo State. However, there are many points yet poorly developed or poorly known, such as the limited number of zoological samples, and the lack of information about the ecology and natural history of many species, respectively. Its extremely important that we increase our samples in the scientific collections, especially in areas of Dense Ombrofilous Forests, in the Cerrado fragments, as well as in central and western areas of the State that continue poorly surveyed. The objective is to produce more taxonomic work in several mammalian groups, and also studies focusing in the phylogeography and in the population genetics in order to effectively diagnose the mammal richness of the State, as well as the evolutionary processes responsible for this diversification. Additionally, ecological data accompanying this information is needed in order to evaluate the conservation status of the Sao Paulo mammals to decide about the better strategies to manage and conserve these mammals. Keywords: mammals, biodiversity of the State of Sao Paulo, BIOTA/FAPESP Program.

Influence of pitfall trap size and design on herpetofauna and small mammal studies in a Neotropical Forest

One of the most commonly used sampling techniques to capture leaf litter amphibians, lizards and small mammals is a set of pitfall traps with drift fences. However, there are still many speculations concerning the effectiveness of different designs of pitfall traps and the most adequate size of each trap. To address this problem, we conducted the first standardized comparison of patterns of species richness, rank-abundance, and community structure of leaf litter amphibians, lizards and small mammals for two trap designs (I and Y format) and three bucket sizes (35, 62, and 100 L) in a Neotropical forest. Results are very similar for the herpetofauna, regardless of the pitfall trap design or size used, while for small mammals values of species richness were higher for 100 L pitfall traps, as compared to the smaller traps. Therefore, the use of 100 L pitfall traps is recommended to sample the terrestrial vertebrate fauna, in multidisciplinary studies. For surveys aiming only the herpetofauna the use of smaller (35 L) traps is acceptable, taking into consideration the cost-benefits obtained by the smaller traps, in comparison to the larger ones.

Phylogenetic Relationships of Mouse Opossums (Didelphidae, Marmosa) with a Revised Subgeneric Classification and Notes on Sympatric Diversity

ABSTRACT To resolve phylogenetic relationships among species of Marmosa we analyzed DNA sequences from one mitochondrial and three nuclear genes for every member of the nominotypical subgenus and from four species of the subgenus Micoureus. As reported in previous studies, the subgenus Marmosa was found to be paraphyletic, whereas Micoureus was recovered as a robustly supported clade. Species currently referred to the subgenus Marmosa form four strongly supported and morphologically diagnosable groups. Based on these results we recognize a total of five subgenera: Marmosa Gray, 1821 (for macrotarsus, murina, tyleriana, and waterhousei); Micoureus Lesson, 1842 (for alstoni, constantiae, demerarae, paraguayana, phaea, and regina); Stegomarmosa Pine, 1972 (for andersoni and lepida); Eomarmosa, new subgenus (for rubra); and Exulomarmosa, new subgenus (for isthmica, mexicana, robinsoni, simonsi, xerophila, and zeledoni). The best-supported hypothesis of relationships among these clades is ((Stegomarmosa (Marmosa + Micoureus)) (Eomarmosa + Exulomarmosa)), and our results additionally resolve many interspecific relationships within each subgenus. These clades have broadly overlapping geographic distributions, especially in western Amazonia, where the arboreal insectivorous-frugivorous niche of Marmosa is apparently partitioned among multiple sympatric congeners.

Mammals of Amapá State, Eastern Brazilian Amazonia: a revised taxonomic list with comments on species distributions

Abstract The Guiana Shield has large, preserved areas with high biological diversity. However, the knowledge of this biodiversity differs among the regions with the Brazilian portion poorly known compared to the French Guiana, Suriname, Guyana, and Venezuela. In the Amapá State, the information on mammals is very heterogeneous and represents a gap in the knowledge of the distribution and diversity of some groups. We compiled a list of the mammals of the Amapá based on the inventories, voucher specimens deposited in the collection Fauna of Amapá at Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá, and previous published studies. We present a list of 181 mammal species. Chiroptera was the order with the highest number of species (88) followed by Rodentia (32). The list includes 17 new occurrences: 16 for Amapá (five marsupials, eight bats, one canid, one cetacea and one rodent) and one for Brazil (one rodent). This species list is the most complete taxonomic review for the Amapá, contributes to the knowledge of mammal diversity north of the Amazon River, and helps increase the precision of the species ranges in the Guianas and the eastern portion of the Amazon.

Occurrence of Marmosa waterhousei in the Venezuelan Andes, with comments on its biogeographic significance

No abstract available

Proechimys (Rodentia, Echimyidae): characterization and taxonomic considerations of a form with a very low diploid number and a multiple sex chromosome system

BackgroundProechimys is the most diverse genus in family Echimyidae, comprising 25 species (two of which are polytypic) and 39 taxa. Despite the numerous forms of this rodent and their abundance in nature, there are many taxonomic problems due to phenotypic similarities within the genus and high intraspecific variation. Extensive karyotypic variation has been noted, however, with diploid numbers (2n) ranging from 14 to 62 chromosomes. Some heteromorphism can be found, and 57 different karyotypes have been described to date.ResultsIn the present work, we describe a cytotype with a very low 2n. Specimens of Proechimys cf. longicaudatus were collected from two different places in northern Mato Grosso state, Brazil (12°54″S, 52°22″W and 9°51′17″S, 58°14′53″W). The females and males had 16 and 17 chromosomes, respectively; all chromosomes were acrocentric, with the exception of the X chromosome, which was bi-armed. The sex chromosome system was found to be XY1Y2, originating from a Robertsonian rearrangement involving the X and a large acrocentric autosome. Females had two Neo-X chromosomes, and males had one Neo-X and two Y chromosomes. NOR staining was found in the interstitial region of one autosomal pair.ConclusionsComparison of this karyotype with those described in the literature revealed that Proechimys with similar karyotypes had previously been collected from nearby localities. We therefore suggest that this Proechimys belongs to a different taxon, and is either a new species or one that requires reassessment.

New records and geographic distribution extension of Neusticomys ferreirai and N. oyapocki (Rodentia, Sigmodontinae)

Abstract Little is known about the genus Neusticomys, one of the most poorly represented sigmodontine rodents in scientific collections. In this report, we provide new records of Neusticomys ferrerai and N. oyapocki in the Brazilian Amazonia and discuss possible limits for their geographic distributions. Three individuals of N. ferreirai were recorded during three distinct survey events. The first record extends the range of the species approximately 100 km westward, and the other two extend it approximately 1000 km northeastward. For N. oyapocki, our record extends the currently known range of the species approximately 300 km westward. All specimens were collected in primary forests by 60-liter pitfall traps. Considering our records of N. ferreirai and the ecoregions associated with them, we argue that the species range may extends north along the interfluves Xingu-Tocantins and Madeira-Tapajós and west to the Guaporé River. Similarly, the limits of the range of N. oyapocki may coincide with the Amazon river at south, the Negro river at west and the transition zones between the Guianan forests and savannas or coastal vegetation at east and north. Larger series of Neusticomys in collections are expected to be available in the future, as more inventories using pitfall traps are carried out in Amazonia.

New records and geographic distribution of the rare Glironia venusta (Didelphimorphia, Didelphidae)

No abstract available

Cryptic Species in Proechimys goeldii (Rodentia, Echimyidae)? A Case of Molecular and Chromosomal Differentiation in Allopatric Populations

The spiny rats of the genus Proechimys have a wide distribution in the Amazon, covering all areas of endemism of this region. We analyzed the karyotype and cytochrome b (Cyt b) sequences in Proechimys goeldii from 6 localities representing 3 interfluves of the eastern Amazon. A clear separation of P. goeldii into 2 monophyletic clades was observed, both chromosomally and based on Cyt b sequences: cytotype A (2n = 26♀/27♂, NF = 42) for samples from the Tapajos-Xingu interfluve and cytotype B (2n = 24♀/25♂, NF = 42) for samples from the Xingu-Tocantins interfluve and east of the Tocantins River. The karyotypes differ in a pericentric inversion and a centric fusion/fission and an average nucleotide divergence of 6.1%, suggesting cryptic species. Meiotic analysis confirmed the presence of a XX/XY1Y2 multiple sex chromosome determination system for both karyotypes. The karyotypes also vary from the literature (2n = 24, NF = 42, XX/XY). The autosome translocated to the X chromosome is different both in size and morphology to P. cf. longicaudatus, which also has a multiple sex chromosome determination system (2n = 14♀/15♀♂/16♀/17♂, NF = 14). The Xingu River is a barrier that separates populations of P. goeldii, thus maintaining their allopatric nature and providing an explanation for the molecular and cytogenetic patterns observed for the Xingu River but not the Tocantins River.