Maurício Beux dos Santos

A new karyotype for Cavia magna (Rodentia: Caviidae) from an estuarine island and C. aperea from adjacent mainland

We describe a new karyotype for Cavia magna Ximenez, 1980 from an estuarine island and the karyotype of Cavia aperea Erxleben, 1777 from an adjacent mainland. The species have differences in diploid number (2n), autosomal fundamental number, quantity, and distribution of heterochromatin as dissimilar distributions of the nucleolus-organizing regions (Ag-NORs). The C. aperea karyotype has a diploid number of 64 as previously reported for C. aperea and most other Cavia species. In contrast, this new C. magna karyotype exhibits a variant diploid number of 2n = 62, considering that previous work reported a karyotype of 2n = 64 for C. magna. The discovery of a distinct diploid number within C. magna represents the first record of intra-specific chromosomal variation in a species of Caviidae. The diploid number of 2n = 62, heterochromatin quantity, Ag-NOR distributions, and inversed X chromosome from this population of C. magna are as seen in the geographically proximate (Cavia intermedia Cherem Olimpio and Ximenez; intermediate Cavy). These data provide further evidence supporting C. magna as the sister species of C. intermedia.

Pequenos mamíferos não-voadores (Didelphimorphia, Rodentia) em dois fragmentos de mata de restinga de Rio Grande, Planície Costeira do Rio Grande do Sul

The restinga forests represent original vegetal formations in Coastal Plain of Rio Grande do Sul state. This work aimed to evaluate the species composition of non-volant small mammals in two restinga forests (peat forest and sandy riparian forest) in Rio Grande, Southern Rio Grande do Sul Coastal Plain. A total of 234 individuals belonging to three species of marsupials (Didelphidae: Cryptonanus guahybae, Didelphis albiventris, Lutreolina crassicaudata) and eight species of rodents (Cricetidae: Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, O. nigripes, Oxymycterus nasutus, Scapteromys tumidus; Muridae: Mus musculus, Rattus rattus) was captured. The species C. guahybae, D. albiventris, D. kempi, H. brasiliensis, O. nigripes, S. tumidus and M. musculus were recorded in the peat forest while C. guahybae, D. albiventris, Lutreolina crassicaudata, D. kempi, O. flavescens, O. nigripes, S. tumidus and R. rattus occurred in the riparian sandy forest. Oligoryzomys nigripes and S. tumidus were the most abundant species in the peat forest, representing 40.4 and 22.1% of the total of captured individuals, respectively. The most abundant species in the riparian sandy forest were O. nigripes e D. albiventris, representing 63.4 and 12.4% of the total of captured individuals. Individuals of C. guahybae and O. nigripes were captured on trees (heights between 0.50 and 1.65 m) while all individuals of the remaining species were captured on the ground.

Diversity and habitat use by snakes and lizards in coastal environments of southernmost Brazil

O estudo teve como objetivo avaliar a composicao de especies de serpentes e lagartos em ambientes costeiros no extremo sul brasileiro. Foram feitas amostragens sistematizadas em habitats de dunas e restingas entre abril de 2009 e marco de 2010 por meio de armadilhas de interceptacao e queda, abrigos artificiais e procuras visuais. O ambiente de restinga revelou uma maior riqueza de especies do que as dunas. As taxocenoses revelaram uma menor riqueza do que a observada em outros biomas brasileiros, o que parece estar associado as condicoes microclimaticas menos estaveis e a baixa complexidade estrutural desses habitats (distribuicao vertical e horizontal da vegetacao). Essa hipotese parece ser reforcada pelo fato de tanto para serpentes quanto para lagartos as especies mais abundantes apresentam habitos fossoriais. Aparentemente a taxocenose de serpentes e determinada predominantemente pelas caracteristicas abioticas (microclima) do habitat enquanto que a de lagartos pelo padrao de cobertura vegetal.

Comportamento alimentar aquático de Liophis jaegeri (Günther 1858) (Serpentes, Dipsadidae) em cativeiro

Dietary composition is an essential component in niche dimension and interferes in the community structuring process. The needs related to feeding behavior drives the way species use their habitats. Despite the wide geographical distribution of Liophis jaegeri, studies concerning its general biology and feeding behavior are very scarce. The available information indicates that L. jaegeri is associated to humid or flooded habits, however the importance of aquatic preys in their diet has not received much attention. In general, the available information suggests that the presence of tadpoles and fishes in the digestive tract of dissected snakes are the result of incidental ingestion. In the present study, we present information on the ability of L. jaegeri to forage in aquatic habitats. Using video recordings made in captivity, we observed that snakes were able to detect, subdue and ingest efficiently the sympatric fish Cheirodon interruptus. These observations suggest that the importance of aquatic preys is higher than previously reported in the literature. Therefore, we believe that the existence of water bodies and the availability of aquatic preys play important roles in the habitat suitability for L. jaegeri snakes.

The Influence of Habitat Configuration on Anuran Species Composition in Subtemperate Wetlands of Southernmost Brazil

Abstract. Wetlands of southern Brazil exhibit unique habitat attributes, such as climate pattern and vegetation cover, that can function as an environmental filter for the establishment of species of Neotropical anurans and influence the composition of anuran assemblages. We examined the role of habitat heterogeneity in the composition and relative abundance of anuran species in subtemperate wetlands of southernmost Brazil. We carried out standardized sampling between May 2009 and April 2011 to examine anuran assemblages in marshes associated with grasslands and coastal dunes, as well as habitat heterogeneity. Habitat heterogeneity and anuran species richness were higher in grasslands. Abundance and species dominance, on the other hand, were higher in dunes. This might be due to more restrictive abiotic filters in dunes, such as the low heterogeneity of vegetation cover and lower availability of water bodies. The most common species in grasslands, Leptodactylus cf. latrans, Elachistocleis bicolor, and Pseudis minuta, exhibited a stronger association with habitats with larger and deeper water bodies and with the presence of floating vegetation. The most abundant species found in dunes, Rhinellla arenarum, Odontophrynus maisuma, and Physalaemus biligonigerus, had a stronger association with low vegetation. In addition to habitat associations, the ability to bury themselves might be a behavioral adaptation to dunes that favor species such as O. maisuma and P. biligonigerus, even under extreme microclimatic conditions. Our findings support the importance of the configuration of vegetation cover as well the heterogeneity of water bodies for the establishment of anuran species in subtemperate marshes of southern Brazil.

Wild boars and feral pigs (Suidae, Sus scrofa) in the Restinga of Rio Grande, RS, Brazil: Ecosystems of occurrence and preliminary data on environmental impacts

O presente trabalho reporta os ecossistemas de ocorrencia de javalis e porcos asselvajados ( Sus scrofa ) na Restinga de Rio Grande, regiao sul da Planicie Lagunar do Rio Grande do Sul, alem de trazer observacoes preliminares sobre impactos ambientais. Entre novembro de 2006 e fevereiro de 2009, foi registrada a presenca de S. scrofa nos seguintes ecossistemas: matas de restinga (mata paludosa e mata arenosa ciliar), pântano salobro, cordao de dunas costeiras e praia oceânica. Em relacao aos tipos fenotipicos, javalis foram observados no interior de ambos os fragmentos florestais, enquanto porcos domesticos foram encontrados no interior e na borda da mata palustre. Nao foi possivel determinar o fenotipo de ocorrencia no cordao de dunas costeiras e no pântano salobro, mas a presenca de S. scrofa nesses ambientes foi registrada atraves da identificacao de pegadas, fezes e escavacoes. A maior area escavada foi localizada no pântano salobro, apresentando 49m de extensao. Foi verificada a remocao da vegetacao graminea e herbacea e de plântulas e plantas jovens de especies arboreas nas areas acometidas por escavacoes. Sementes de Syagrus romanzoffiana foram identificadas em amostras de fezes no interior da mata palustre. Estes representam os primeiros registros de javalis asselvajados nos ambientes de restingas costeiras do Estado, incluindo o municipio de Rio Grande na relacao dos municipios rio-grandenses com ocorrencia confirmada da especie em vida livre, que ate o momento somam 32 localidades. Palavras-chave: especie exotica invasora, matas de restinga, pântano salobro, Suidae.