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‣ Skull Modularity in Neotropical Marsupials and Monkeys: Size Variation and Evolutionary Constraint and Flexibility

SHIRAI, Leila T.; MARROIG, Gabriel
Fonte: WILEY-LISS Publicador: WILEY-LISS
Tipo: Artigo de Revista Científica
Português
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An organism is built through a series of contingent factors, yet it is determined by historical, physical, and developmental constraints. A constraint should not be understood as an absolute obstacle to evolution, as it may also generate new possibilities for evolutionary change. Modularity is, in this context, an important way of organizing biological information and has been recognized as a central concept in evolutionary biology bridging on developmental, genetics, morphological, biochemical, and physiological studies. In this article, we explore how modularity affects the evolution of a complex system in two mammalian lineages by analyzing correlation, variance/covariance, and residual matrices (without size variation). We use the multivariate response to selection equation to simulate the behavior of Eutheria and Metharia skulls in terms of their evolutionary flexibility and constraints. We relate these results to classical approaches based on morphological integration tests based on functional/developmental hypotheses. Eutherians (Neotropical primates) showed smaller magnitudes of integration compared with Metatheria (didelphids) and also skull modules more clearly delimited. Didelphids showed higher magnitudes of integration and their modularity is strongly influenced by within-groups size variation to a degree that evolutionary responses are basically aligned with size variation. Primates still have a good portion of the total variation based on size; however...

‣ Diet and food selection by small mammals in an old-growth Atlantic forest of south-eastern Brazil

PINOTTI, Bruno T.; NAXARA, Laura; PARDINI, Renata
Fonte: TAYLOR & FRANCIS LTD Publicador: TAYLOR & FRANCIS LTD
Tipo: Artigo de Revista Científica
Português
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Here we describe the stomach contents of nine small mammal species (seven rodents and two didelphid marsupials) co-occurring in an old-growth Atlantic forest area. For four terrestrial rodents, we also compared the importance of arthropods in the diet and the selection of arthropod groups by comparing consumption with availability. Small mammals and arthropods were sampled in a 36-ha grid containing 25 sampling stations spaced every 150 m, and 47 stomach contents were analysed. While plant matter was the predominant item in the stomach contents of two rodents (Oligoryzomys nigripes and Rhipidomys mastacalis), four species presented arthropods as the main food item (the rodents Brucepattersonius soricinus and Oxymycterus dasytrichus, and the marsupials Monodelphis n. sp. and Marmosops incanus) and three consumed more plant matter than arthropods, but had significant amounts of both items (the rodents Delomys sublineatus, Euryoryzomys russatus and Thaptomys nigrita). Our results suggest that differences in diet, coupled with differences in habit and microhabitat preferences, are important factors allowing resource partition among species of the diverse group of co-occurring terrestrial small mammals in Atlantic forest areas. Moreover...

‣ Variety matters: adaptive genetic diversity and parasite load in two mouse opossums from the Brazilian Atlantic forest

MEYER-LUCHT, Yvonne; OTTEN, Celine; PUETTKER, Thomas; PARDINI, Renata; METZGER, Jean Paul; SOMMER, Simone
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
Português
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The adaptive potential of a species to a changing environment and in disease defence is primarily based on genetic variation. Immune genes, such as genes of the major histocompatibility complex (MHC), may thereby be of particular importance. In marsupials, however, there is very little knowledge about natural levels and functional importance of MHC polymorphism, despite their key role in the mammalian evolution. In a previous study, we discovered remarkable differences in the MHC class II diversity between two species of mouse opossums (Gracilinanus microtarsus, Marmosops incanus) from the Brazilian Atlantic forest, which is one of the most endangered hotspots for biodiversity conservation. Since the main forces in generating MHC diversity are assumed to be pathogens, we investigated in this study gastrointestinal parasite burden and functional associations between the individual MHC constitution and parasite load. We tested two contrasting scenarios, which might explain differences in MHC diversity between species. We predicted that a species with low MHC diversity would either be under relaxed selection pressure by low parasite diversity (`Evolutionary equilibrium` scenario), or there was a recent loss in MHC diversity leading to a lack of resistance alleles and increased parasite burden (`Unbalanced situation` scenario). In both species it became apparent that the MHC class II is functionally important in defence against gastrointestinal helminths...

‣ SEASONAL MICROHABITAT SELECTION BY TERRESTRIAL RODENTS IN AN OLD-GROWTH ATLANTIC FOREST

NAXARA, Laura; PINOTTI, Bruno T.; PARDINI, Renata
Fonte: ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS Publicador: ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS
Tipo: Artigo de Revista Científica
Português
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We tested the hypothesis that microhabitat variables, abundance of terrestrial rodents, and microhabitat selection patterns of terrestrial rodents vary between the cool-dry and warm-wet season in the Atlantic forest of Brazil. We selected variables associated with ecological factors potentially important to terrestrial rodents (physical structure of litter and woody debris, and arthropod availability) and established 25 small, independent sampling units covering 36 ha of a homogenous, mature Atlantic forest patch. Litter humidity and height, amount of small woody debris, arthropod availability, and terrestrial rodent abundance increased, whereas the quantity of large woody debris decreased in the warm-wet season. Greater spatial segregation among terrestrial rodents also was observed in this season, especially between morphologically similar species. The distribution of 3 of the 4 most common terrestrial rodents was influenced by microhabitat variables in at least I of the seasons, and these species also differed in their pattern of microhabitat selection between seasons. In general, the amount of small woody debris and litter humidity were more important for the microscale distribution of terrestrial rodents in the cool-dry season...

‣ Pequenos mamíferos não voadores da estação ecológica de Bananal, SP; Nonvolant small mammals of Estação Ecológica de Bananal, SP

Abreu Júnior, Edson Fiedler de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/02/2014 Português
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A Floresta Atlântica comparada a outros biomas brasileiros é proporcionalmente o mais diverso em espécies de mamíferos e com a maior taxa de endemismo. Dentre todos os mamíferos do Bioma, os pequenos não voadores constituem o grupo mais diversificado, representando acima de um terço da diversidade total, com cerca de 105 espécies. Contudo, ainda estamos longe da compreensão ideal de diversos aspectos que acercam a delimitação de grande parte destas espécies, como a amplitude da variação morfológica, suas relações filogenéticas e suas características biogeográficas. Em parte, isto se deve a falta de estudos que integram estas questões, por exemplo, através da descrição detalhada de faunas locais, como tem ocorrido para a região Amazônica. Neste contexto, o presente estudo teve por objetivo reconhecer a fauna de pequenos mamíferos não voadores da Estação Ecológica de Bananal (EEB), região nordeste do Estado de São Paulo, e apresentá-la através de uma lista comentada; além de discutir alguns aspectos biogeográficos do grupo no Bioma. Para isto foram examinados cerca de 550 espécimes colecionados nos anos de 2003, 2004 e 2011 na EEB e depositados no Museu de Zoologia da Universidade de São Paulo (MZUSP); foram examinados ainda...

‣ Pequenos mamíferos não voadores (Mammalia: Didelphimorphia e Rodentia) do baixo rio Xingu; Nonvolant mammals (Mammalia: Didelphimorphia and Rodentia) of the lower Xingu river

Godoy, Leandro Perez
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/05/2015 Português
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A região amazônica se destaca como a área de floresta tropical mais extensa e diversa do mundo. Essa diversidade é especialmente válida para os pequenos roedores e marsupiais que compõem o grupo mais diversificado de mamíferos Neotropicais, com estimativas de ocorrência de cerca de 107 espécies, sendo 91 endêmicas deste bioma. No entanto, nosso conhecimento sobre os limites específicos e geográfico destas espécies, bem como sua origem ainda está em sua infância. Diversas hipóteses buscam explicar essa a origem desta diversidade, sendo a dos rios como barreiras geográficas uma interpretação de diversificação para esta região, especialmente em grandes rios como o Xingu, que tem seu curso reto e seus tributários fluindo por um declive íngreme do norte do Escudo Brasileiro. Nesse contexto, o presente trabalho teve o objetivo de elaborar uma lista detalhada das espécies de pequenos mamíferos não voadores da região do baixo rio Xingu e discutir aspectos biogeográficos desse grupo para a Bacia Amazônica. Foram analisados aproximadamente 320 indivíduos obtidos através de visitas a coleções zoológicas e provenientes do Programa de Monitoramento, Resgate e Aproveitamento Científico da Fauna da Usina Hidrelétrica de Belo Monte. Foram realizadas análises quali- e quantitativas de características externas e crânio-dentárias...

‣ Distribuição da família Didelphidae (Mammalia, Didelphimorphia) no Rio Grande do Sul, Brasil; Distribution of didelphidae family (Mammalia, Didelphimorphia) in Rio Grande do Sul, Brazil

Ávila, Maurício Cendon do Nascimento
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
Português
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Os marsupiais são um importante componente da fauna de mamíferos sul-americanos e suas adaptações a diversos tipos de hábitat lhes permitiram ocupar diferentes nichos ecológicos. A família Didelphidae é a única família pertencente à ordem Didelphimorphia e compreende a maioria das espécies viventes de marsupiais americanos. Atualmente a família inclui 95 espécies reconhecidas, distribuídas em 19 gêneros recentes, das quais somente quatro não ocorrem na América do Sul. A sua distribuição é ampla e ocorre naturalmente do sudeste do Canadá até o sul da Argentina. As espécies ocupam todos os grandes biomas e quase todos os tipos de hábitats dentro deles com exceção de altitudes muito elevadas e das regiões extremamente desertificadas. No Brasil ocorrem 55 espécies de marsupiais da família Didelphidae divididas em quatro subfamílias, Glironiinae, Caluromyniae, Hyladelphinae e Didelphinae, distribuídas em 16 gêneros, das quais possivelmente 14 espécies ocorrem no Rio Grande do Sul. Ainda existem lacunas no que diz respeito à distribuição e taxonomia de muitas espécies de marsupiais e a falta de estudos focando esse grupo no extremo sul do Brasil dificulta ainda mais a compreensão da sua diversidade nessa região. Neste contexto...

‣ Evolutionary diversification in Central Brazil: where Amazonia and Cerrado meet; Diversificação evolutiva no Brasil Central: onde a Amazónia e o Cerrado se encontram

Rocha, Rita Gomes
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
Português
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Apesar da fauna de mamíferos Neotropicais ser uma das mais ricas do mundo, o nosso conhecimento sobre os limites de espécies, distribuições geográficas e relações filogenéticas está ainda agora no seu início. As áreas de transição entre os dois maiores biomas da América do Sul, o Cerrado e a Amazónia, são ainda menos conhecidas. Até ao momento, escassos estudos focaram os pequenos mamíferos destas áreas. Destes estudos, apenas dois apresentam dados taxonómicos e de distribuição geográfica de uma lista de espécies reduzida e, nenhum é focado nos processos evolutivos que conduziram à diversidade destas áreas. O presente trabalho tem como objectivo aumentar o conhecimento básico sobre a diversidade do médio Rio Araguaia, na região central do Brasil, através da amostragem e análise de espécies de pequenos mamíferos, integrando um intenso trabalho de campo, de laboratório e de museu. Desta forma, um total de 22 espécies é registado para o médio Araguaia. De entre estas espécies, descreve-se uma espécie nova de Rhipidomys, regista-se uma espécie não descrita de Thrichomys e uma potencial nova forma de Oligoryzomys, e também se apresenta uma diagnose emendada do obscuro Oecomys cleberi. Para cada espécie...

‣ Microhabitat of small mammals at ground and understorey levels in a deciduous, southern Atlantic Forest

MELO,GERUZA L.; MIOTTO,BARBARA; PERES,BRISA; CACERES,NILTON C.
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 Português
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Each animal species selects specific microhabitats for protection, foraging, or micro-climate. To understand the distribution patterns of small mammals on the ground and in the understorey, we investigated the use of microhabitats by small mammals in a deciduous forest of southern Brazil. Ten trap stations with seven capture points were used to sample the following microhabitats: liana, fallen log, ground litter, terrestrial ferns, simple-trunk tree, forked tree, and Piper sp. shrubs. Seven field phases were conducted, each for eight consecutive days, from September 2006 through January 2008. Four species of rodents (Akodon montensis, Sooretamys angouya, Oligoryzomys nigripes and Mus musculus) and two species of marsupials (Didelphis albiventris and Gracilinanus microtarsus) were captured. Captured species presented significant differences on their microhabitat use (ANOVA, p = 0.003), particularly between ground and understorey sites. Akodon montensis selected positively terrestrial ferns and trunks, S. angouya selected lianas, D. albiventris selected fallen trunks and Piper sp., and G. microtarsus choose tree trunks and lianas. We demonstrated that the local small-mammal assemblage does select microhabitats, with different types of associations between species and habitats. Besides...

‣ The importance of understorey on wildlife in a brazilian eucalypt plantation

Stallings,Jody R.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1990 Português
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Wildlife surveys were conducted in two stands of Eucalyptus, one homogeneous and the other with a native species understorey in the Atlantic forest region of southeastern Brazil Deforestation has reduced the original forested habitat to a patchwork of cultivated fields and mono-specific forestry plantations. Wildlife communities were depauperate in the homogeneous stand, but richer in eucalypt forest with native species understorey. Small mammals, particularly didelphid marsupials, used the understorey rather than the eucalypt emergent trees Primates were absent from both areas. The increasing demand for charcoal for the growing steel industry in the region means that eucalypt plantations will persist until an alternative energy source is found. It is essential that management efforts be directed towards multi-use strategies in these plantations Eucalypt plantations with a native species understorey might provide sufficient habitat to support some wildlife species of the rapidly disappearing Atlantic coastal forest ecosystem.

‣ Comparative lengths of digestive tracts of seven didelphid marsupials (Mammalia) in relation to diet

Cáceres,Nilton C.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2005 Português
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The relative proportions of the digestive tract were rarely explored to understand the behaviour and the ecology of neotropical marsupials. In this study, proportions of the digestive tract and diet were compared in seven opossum species. The animals studied were Didelphis albiventris Lund, 1840, D. aurita Wied-Neuwied, 1826, Metachirus nudicaudatus (Desmarest, 1817), Philander frenatus (Olfers, 1818), Lutreolina crassicaudata Desmarest, 1804, Monodelphis sorex (Hensel, 1872) and Caluromys lanatus (Olfers, 1818). Segments of digestive tracts of marsupials were measured and differences were statistically tested by Analysis of Variance and Covariance. Caecum and hard guts were responsible for the main differences among opossums, although all segments differed significantly. Caluromys lanatus was the most specialised species, with a large hard gut and caecum, small stomach and shorter small gut. The large caecum of M. nudicaudatus and the shortest hard gut of M. sorex were also noticed. The arboreal C. lanatus has a well different feeding habit and life style regarding other marsupials studied, such as M. sorex and M. nudicaudatus which are terrestrial, corroborating the results reached.

‣ Effects of gut passage on the germination of seeds ingested by didelphid marsupials in a neotropical savanna

Lessa,Leonardo Guimarães; Geise,Lena; Costa,Fabiane Nepomuceno
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2013 Português
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We analyzed the effects that passage through the guts of seven didelphid species had on the seed germination of 10 plant species. This study was conducted in an area of riparian woodland in a cerrado (savanna) reserve in southeastern Brazil. We found seeds of 23 angiosperm species in 427 fecal samples obtained from seven didelphid species. The plant families most often represented by the seeds found in the fecal samples were Melastomataceae (5 species) and Rubiaceae (4 species) . Most gut-passed seeds showed no significant difference in germinability when compared with the hand-extracted seeds. Among the ingested seeds, only those of Clidemia urceolata DC. (Melastomataceae) and Myrcia sp. (Myrtaceae) showed an increase in germinability (final proportion of germinated seeds), indicating that didelphid gut passage does not always benefit seed germination. The average germination time of consumed seeds ranged from 12 days (Cipocereus minensis (Werderm.) Ritter) to 171 days (Cordiera sessilis (Vell.) Kuntze). The small number of seeds destroyed after gut passage and the results obtained during the germination experiments underscore the importance of didelphid marsupials to the dynamics of plant reproduction, especially those of small-seeded cerrado species.

‣ Artificial nests as an alternative to studies of arboreal small mammal populations: a five-year study in the Atlantic Forest, Brazil

Loretto,Diogo; Vieira,Marcus Vinícius
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 Português
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Despite the great diversity of Brazilian Atlantic forest small mammals, natural history of most species is unknown due to their cryptic and nocturnal habits, but also due to the inadequacy of methods to capture some species, especially those of arboreal habits. A new technique, based on the use of artificial nests (AN) to record arboreal marsupials, is presented. Artificial nests were combined with traditional live traps to study the population ecology of four didelphid marsupial species. After 62 months of monitoring, 119 individuals were recorded 243 times (total success = 5.2%). Only 26 individuals (22%) were recorded by both AN and live trap methods, and two of the four species were never captured by live traps, only by AN. Live traps alone would have provided biased data of the structure of small mammal assemblages, creating artificial tendencies in population dynamics of many species. Detectability estimates based on mark-recapture data could correct bias resulting from the use only live traps, but these estimates require that at least some individuals of each age class or stage are captured. Only the combination of AN and live traps can produce more accurate data on population dynamics and assemblage structure. This study demonstrates that artificial nests represent a new method that should be combined with live traps in studies of small mammal assemblages and populations.

‣ Helminths of three species of opossums (Mammalia, Didelphidae) from Mexico

Acosta-Virgen, Karla; López-Caballero, Jorge; García-Prieto, Luis; Mata-López, Rosario
Fonte: Pensoft Publishers Publicador: Pensoft Publishers
Tipo: Artigo de Revista Científica
Publicado em 02/07/2015 Português
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From August 2011 to November 2013, 68 opossums (8 Didelphis sp., 40 Didelphis virginiana, 15 Didelphis marsupialis, and 5 Philander opossum) were collected in 18 localities from 12 Mexican states. A total of 12,188 helminths representing 21 taxa were identified (6 trematodes, 2 cestodes, 3 acanthocephalans and 10 nematodes). Sixty-six new locality records, 9 new host records, and one species, the trematode Brachylaima didelphus, is added to the composition of the helminth fauna of the opossums in Mexico. These data, in conjunction with previous records, bring the number of taxa parasitizing the Mexican terrestrial marsupials to 41. Among these species, we recognized a group of helminths typical of didelphids in other parts of the Americas. This group is constituted by the trematode Rhopalias coronatus, the acanthocephalan Oligacanthorhynchus microcephalus and the nematodes Cruzia tentaculata, Gnathostoma turgidum, and Turgida turgida. In general, the helminth fauna of each didelphid species showed a stable taxonomic composition with respect to previously sampled sites. This situation suggests that the rate of accumulation of helminth species in the inventory of these 3 species of terrestrial marsupials in the Neotropical portion of Mexico is decreasing; however...

‣ Dieta e Frugivoria por Marsupiais Didelfideos em uma floresta estacional semidecidual no Parque Nacional Do Iguaçu, Paraná, Brasil

Casella, Janaina
Fonte: Universidade Federal de Mato Grosso do Sul Publicador: Universidade Federal de Mato Grosso do Sul
Tipo: Dissertação de Mestrado
Português
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Atualmente a ordem Didelphimorphia apresenta uma única família, denominada Didelphidae, distribuída ao longo do continente americano (Emmons & Feer, 1997). No Brasil, são conhecidos pelo menos 15 gêneros e 65 espécies (Fonseca et al., 1996). Esse número ultrapassa 70 espécies quando considerada toda a Região Neotropical (Emmons & Feer, 1997). Os marsupiais neotropicais ocorrem desde as florestas austrais e habitats arbustivos da Patagônia, passando pelos Andes e toda extensão das florestas de planície subtropicais e tropicais, cerrados e chaco, até as regiões áridas de caatinga. Estendem-se ainda, representados por uma única espécie de gambá (Didelphis virginiana), até as regiões temperadas da América do Norte (Emmons & Feer, 1997). Os marsupiais didelfídeos ocupam uma grande variedade de nichos, sendo a maior parte dos gêneros de marsupiais neotropicais arborícolas ou ao menos escansoriais (Fonseca et al., 1996; Emmons & Feer, 1997). Podem ocupar um gradiente desde as espécies mais frugívoras, onívoras até as mais carnívoras (Santori & Astúa de Moraes, 2005). Essas diferenças entre as espécies nos nichos que ocupam podem permitir a coexistência de um maior número de espécies na comunidade, e devem implicar em especializações da morfologia diretamente ligadas à locomoção e à alimentação (Vieira...

‣ Morphological diversity in digital skin microstructure of didelphid marsupials

HAMRICK, MARK W.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/2001 Português
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The purpose of this study was to investigate how didelphid marsupials have diversified in morphology of their claws and digital pads as they evolved different foraging preferences such as terrestrial, aquatic, and arboreal feeding behaviours. Both arboreal and more terrestrial didelphids have papillary ridges on the digital pads of the fore and hindfoot. In contrast, the papillary ridges on the pedal digital skin of the water opossum Chironectes minimus have been replaced by nonoverlapping, thickened epidermal scales. Chironectes also differs from the other didelphids studied in having finger tips with reduced claws and digital pads that are covered with raised epidermal scales having projecting, finger-like cones arranged radially around the perimeter of each scale. The reduced claws and unusual digit skin microstructure of Chironectes likely improve this animal's ability to recognise and identify live animal prey under water using only its sense of touch.

‣ Ecology of small mammals in a Brazilian rural area

D'Andrea,Paulo Sergio; Gentile,Rosana; Cerqueira,Rui; Grelle,Carlos Eduardo V; Horta,Claudia; Rey,Luis
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1999 Português
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A small mammal study was carried out in Pamparrão valley, Sumidouro, State of Rio de Janeiro, Brazil, from June 1991 to July 1996. The area was characterised by small rural properties with vegetable plantations, pasture lands and small forest fragments. Small mammals were captured in seven line transects along the valley. Eleven small mammal species were captured: the didelphid marsupials Didelphis aurita, Philander frenata and Monodelphis americana, and the rodents Nectomys squamipes, Akodon cursor, Oligoryzomys nigripes, Bolomys lasiurus, Oecomys concolor (Sigmodontinae), Rattus ratlus (Murinae), Proechimys iheringi and Euryzygo-matomys guiara (Echimyidae). The heterogeneous habitat configuration probably allowed the occurrence of marsupials and more rodent species when compared to studies in monoculture areas.

‣ Jumping ability in the arboreal locomotion of didelphid marsupials

Delciellos,Ana Cláudia; Vinícius Vieira,Marcus
Fonte: Mastozoología neotropical Publicador: Mastozoología neotropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2009 Português
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Didelphid marsupials are considered to cross discontinuities between arboreal supports using a cautious locomotion, using the prehensile tail as fifth limb. However, this ability was only described for Caluromys philander. We describe and compare the locomotory performance and postural behavior of seven species of didelphid marsupials crossing discontinuities between artificial supports representing arboreal gaps. Individuals were captured in areas of Atlantic Forest in Rio de Janeiro State, Brazil. Animals were stimulated to jump from a fixed horizontal support one meter above the ground to an inclined support of same diameter. We measured the maximum distance of jump (40, 60, 80 or 100 cm) and reach or distance actually reached by the jump. Arboreal species (Marmosops incanus, Gracilinanus microtarsus, Micoureus paraguayanus, and C. philander) jumped longer distances and had longer relative reach in jumps than semi-terrestrial species (Didelphis aurita, and Philander frenatus). Only the specialized terrestrial Metachirus nudicaudatus did not jump in the tests. The relation between absolute reach and body size was weak and non significant. This study did not corroborate the view that didelphid marsupials cross discontinuities between arboreal supports only through a cautious locomotion...

‣ Diet variation of the marsupials Didelphys aurita and Philander frenatus (Didelphimorphia, Didelphidae) in a rural area of Rio de Janeiro state, Brazil

Ceotto,Paula; Finotti,Ricardo; Santori,Ricardo; Cerqueira,Rui
Fonte: Mastozoología neotropical Publicador: Mastozoología neotropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 Português
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We studied the natural diet of two didelphid marsupial species, Didelphis aurita and Philander frenatus, at a rural area on southeastern Brazil, through fecal sample analysis. Data analysis included intraspecific comparisons (age, gender, and climatic seasons) and interespecific comparisons. Frequencies of food items were compared with other studies to analyze diet differences in a spatial scale. Invertebrates were the most frequent food category found in samples of both species, followed by fruits and vertebrates. There were no differences in the consumption of invertebrates, vertebrates and fruits between sexes in the two species, but both consumed more fruits in more humid months. Juveniles of P. frenatus consumed less vertebrates than adults or subadults. P. frenatus consumed more vertebrates than D. aurita, which exhibited a higher diversity of fruits in its diets. These differences represent an important factor in diminishing intraspecific competition. Among different localities, invertebrates are the more common items in the diet of both species, being a fundamental alimentary resource, whereas fruit consumption seems to be smaller in the areas where water is less available (areas with longer periods or higher hidric deficits)...