RESUMO Das 1.361 espécies de vertebrados que a Mata Atlântica abriga, 567 são endêmicas. Rodentia e Didelphimorphia somam 71% dos endemismos observados para mamíferos nesse bioma. No Brasil, esses animais ainda carecem de informações básicas a cerca de sua biologia, distribuição, e mesmo riqueza total. Esse trabalho objetivou identificar as espécies de marsupiais e roedores do Parque Estadual Rio da Onça e caracterizar a morfologia dos pelos-guarda e do conjunto cromossômico das mesmas, além de verificar a composição de pequenos mamíferos não voadores em diferentes ambientes e estratos vegetais. Foram realizadas treze campanhas de campo e como esforço adicional, três linhas de armadilhas de queda foram instaladas. O esforço amostral total foi de 6.633 armadilhas e 1.181 baldes distribuídos ao longo de 69 noites de amostragem, que resultaram em 196 capturas de 166 indivíduos de 12 espécies. Foram registradas sete espécies da Ordem Rodentia: Akodon montensis, Delomys sublineatus, Euryoryzomys russatus, Juliomys pictipes, Nectomys squamipes, Oligoryzomys nigripes e Thaptomys nigrita, além de cinco espécies de marsupiais da Ordem Didelphimorphia: Didelphis aurita, Gracilinanus microtarsus, Metachirus nudicaudatus, Marmosa paraguayana e Monodelphis iheringi. Os resultados tricológicos e citogenéticos foram condizentes com os disponíveis na literatura. Quanto à estratificação vertical, somente sete capturas foram feitas em árvore: quatro da espécie Marmosa paraguayana, duas de Didelphis aurita e uma de Akodon montensis. Portanto, para o ambiente de Terras Baixas da área de estudo, a amostragem realizada no extrato arbóreo e arbustivo do sub-bosque não contribuiu para o incremento da lista de espécies.

ABSTRACT The Atlantic forest possess 1,361 vertebrate species of which 567 are endemic. Rodentia and Didelphimorphia comprise 71% of the endemic mammals observed in this biome. In Brazil, these animals still lack basic information about their biology, distribution, and even total wealth. This study aimed to identify the species of marsupials and rodents present in Rio da Onça State Park and to characterize the morphology of guard hairs and chromosomal set thereof, besides verify the composition of small non-flying mammals in different environments and vegetation strata. Thirteen field campaigns were conducted and as an additional effort, three lines of pitfall traps were installed. The total sampling effort was 6.633 traps and 1.181 buckets spread over 69 nights of sampling, which resulted in 196 captures of 166 individuals of 12 species. Seven species of Rodentia Order were recorded: Akodon montensis, Delomys sublineatus, Euryoryzomys russatus, Juliomys pictipes, Nectomys squamipes, Oligoryzomys nigripes and Thaptomys nigrita and five species of marsupials (Didelphimorphia Order): Didelphis aurita, Gracilinanus microtarsus, Metachirus nudicaudatus, Marmosa paraguayana and Monodelphis iheringi. Trichological and cytogenetic results were consistent with those available in the literature. Regarding the vertical stratification, only seven captures were made in trees. Four of the species Marmosa paraguayana, two Didelphis aurita, and one Akodon montensis. Therefore, in the environment of the lowlands of the study area, sampling carried out on tree and shrub extract of the understory did not contribute to the increase of the species list.

No Brasil há 10 espécies de Akodon Meyen, 1833 e a maioria apresenta algum grau de sobreposição geográfica havendo inclusive registros de simpatia. A identificação das espécies é difícil e pode ser feita pela análise da estrutura morfológica de pelos. Assim, para a identificação da microestrutura de pelos de nove espécies brasileiras de Akodon, foram utilizados pelos-guardas primários de amostras de coleções zoológicas. Foi adotado o método de análise das escamas cuticulares e da medula. O padrão de cutícula para todas as espécies foi folidáceo estreito. Já para a medula foram reconhecidos três padrões básicos como multisseriada alveolar, multisseriada listrada e misto de alveolar e listrada. Akodon cursor é a única espécie com predomínio de quatro fileiras sendo que exemplares 2n = 14 e 2n = 15 apresentam medula alveolar e o 2n = 16, medula listrada e células longilíneas. Para Akodon paranaensis e A. lindberghi a medula se alterna entre três e quatro fileiras. As demais espécies apresentam três fileiras. Akodon mystax apresenta um maior espaçamento entre as células. Akodon reigi possui o setor intermediário com fileiras ovaladas e bem ligadas e Akodon toba tem as células da fileira central variando com uma e duas células alveolares pequenas. No padrão listrado, Akodon montensis apresenta espaço intercelular mais estreito em relação à espessura da célula. No padrão misto, Akodon azarae apresenta células com contorno evidente, já Akodon serrensis as células apresentam formato irregular. Assim, o uso da microestrutura dos pelos como ferramenta para a identificação das espécies de Akodon mostrou-se perfeitamente viável.

There are 10 species of Akodon Meyen, 1833 in Brazil and most have some degree of geographic overlap, even with records of sympatry between some species. The identification of the species is difficult and can be performed by the analysis of the morphological structure of hair. Thus, in order to identify the microstructure of the nine Brazilian species of Akodon, guard-hairs samples from zoological collections were used. We adopted the method of analysis of the cuticle scales and medulla. The cuticle pattern for all species was narrow leaf shaped. For the medulla three basic patterns have been recognized: alveolar multiseriate, multiseriate striped and a mixture of alveolar and striped. Akodon cursor is the only species which has a predominance of four layers of cells, the specimens 2n = 14 and 2n = 15 have an alveolar medulla and the specimen 2n = 16, has a striped medulla and elongated cells. For Akodon paranaensis and A. lindberghi the medulla alternates between three and four layers. The others species have three layers. Akodon mystax, have a larger spaces between the cells. Akodon reigi shows an intermediary sector with layers of oval and well connected cells and for Akodon toba, the cells of the central layer are found in one or two small alveolar layers. In the striped pattern, Akodon montensis have narrow intercellular space in regard to the thickness of the cell. In a mixed pattern, Akodon azarae presents cells with clear outline, and Akodon serrensis show cells with irregular shape. Thus, the use of the microstructure of hairs as a tool for identification of the species of Akodon proved to be practicable.

Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA3/DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA3/DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time.

In this study, the microsatellite technique was used to evaluate the genetic variability in populations of collared and white-lipped peccaries kept in captivity. Six primers developed for domestic pigs were used and amplified in both species. They revealed the presence of five polymorphic loci and one monomorphic locus. The polymorphic loci included 4 of the 16 alleles in collared peccaries, and 3 of the 10 alleles in the white-lipped peccaries. Polymorphic information content (PIC) in both species and all the loci was highly informative. The probability of paternity exclusion (PEC), if one of the parents is known, was almost as high in white-lipped peccaries (95.53%) as in the collared (99,48%). The Fst values for collared (0.042) and white-lipped (0.1387) peccaries showed that both populations are not structured. The Fis values for all loci, except ACTG2 in white-lipped peccaries (-0.0275) and in both species (0.1985 to 0.9284 in collared peccaries and 0.3621 to 0.4754 in the white-lipped), revealed a high level of homozygosis, probably caused by inbreeding. Data on heterologous amplification and genetic variability in collared and white-lipped peccaries are presented for the first time.

This paper describes, for the first time, the cytogenetic characteristics of some South Atlantic nereidid polychaetes, collected in Paranaguá Bay, southeast Brazil. Mitotic chromosomes were obtained from regenerative tissue after amputation of the posterior tips of the animals. Seven species, of five genera, were analyzed: 1) Platynereis dumerilii (2n=28; FN=56), which is considered cosmopolitan but is suspected to be a species-complex. Karyotypic divergences were detected when comparing chromosome morphology and NOR distribution from Paraná and North American populations (2n=28; FN=56), 2) Perinereis vancaurica (2n=28; FN=56), P. anderssoni (2n=28; FN=56) and P. ponteni (2n=28; FN=54). Karyotypes and NOR distribution allowed us to relate P. anderssoni (Paraná, Brazil) to P. macropus (Italy), the former showing a derived karyotype. The remaining karyotypes of species of Perinereis showed independent divergences; 3) Pseudonereis palpata (2n=28; FN=56), known from the south and south-east coast of Brazil; 4) Nereis oligohalina (2n=28; FN=50), occurring in the South Atlantic. The last two species share the conservative chromosome number of the family; and 5) Laeonereis culveri, occurring in both the South and North Atlantic, has the highest chromosome number in the family (2n=38). We discuss the important role of karyotypic evolution in the origin of modern families of polychaetes, when the current chromosomal diversity (2n=6 to 2n=64) was developed, followed by a period of chromosomal stability of nereidid polychaetes during the dispersion which followed the Pangea breakup, with the predominance of divergences of neutral chromosomal changes, involving mainly pericentric inversions and NOR amplifications.

Se describen por primera vez, las características citogenéticas de poliquetos nereidídeos provenientes de la Bahía de Paranaguá, sudeste de Brazil. Cromosomas mitóticos fueron obtenidos a partir de tejido regenerativo después de amputar la región posterior. Fueron analizadas siete especies pertenecientes a cinco géneros: 1) Platynereis dumerilii (2n=28; FN=56), considerada cosmopolita pero que probablemente constituya un complejo de especies. Fueron detectadas divergencias cariotípicas al comparar morfología cromosómica y distribución de NORs entre poblaciones de Paraná y Atlántico Norte, 2) Perinereis vancaurica (2n=28; FN=56), P. anderssoni (2n=28; FN=56) y P. ponteni (2n=28; FN=54). Los cariotipos y distribución de NOR permitieron relacionar P. anderssoni (Paraná, Brazil) con P. macropus (Italia), presentando la primera un cariotipo derivado. Los restantes cariotipos del género mostraron divergencias independientes; 3) Pseudonereis palpata (2n=28; FN=56), distibuída en el sur y sudeste de la costa brasilera; 4) Nereis oligohalina (2n=28; FN=50), que ocurre en el Atlántico sur. Las últimas dos especies comparten el número cromosómico conservado de la familia, y 5) Laeonereis culveri, que ocurre en toda la costa Atlántica, mostró el número cromosómico más alto de la familia (2n=38). Se discute la evolución cariotípica como rol importante durante el origen de las familias modernas de Poliquetos, cuando surge la actual diversidad cromosómica (2n=6 a 2n=64), seguido de un período de establidad cariotípica dentro de la familia Nereididae durante su dispersión, posterior a la ruptura de la Pangea, a partir de la cual pasan a predominar divergencias cromosómicas neutras, involucrando principalmente inversiones pericéntricas y amplificaciones de NORs.

Os animais silvestres têm sido utilizados como bioindicadores quando o ambiente é exposto a estressores químicos. Em geral, os agentes químicos podem induzir às alterações cromossômicas dos tipos falhas e quebras. Tayassu tajacu, é uma espécie aparentada dos porcos verdadeiro e apresenta uma grande estabilidade cariotípica. As únicas alterações descritas são em relação a forma do cromossomo X. Foram observadas falhas e quebras cromossômicas durante as análise citogenética. Estas alterações foram detectadas em cromossomos autossômicos. Levantamentos realizados na literatura associados as dados observados nos exemplares estudados, indicam um vermífugo, a base de ivermectina, como o possível causador dessas alterações cromossômicas.

Wild animals have been used as bioindicators in situations in which the environment was exposed to chemical agents. In general, chemical agents may induce chromosomal aberrations, such as breaks and gaps. The peccary, Tayassu tajacu is a pig relative that exhibits a very stable karyotype with the only described alterations being of the form of the X chromosome. Chromosomal gaps and breaks were observed at high frequencies during cytogenetics analyses. These alterations were observed in the chromosomes autossomics. Reviews of the literature and of the data described herein suggests that an vermifuge, the ivermectin base, was the most likely cause of these chromosomal alterations.

Sixteen species of ectoparasites were collected from 50 wild rodents, from August 1990 to August 1991, in an area of Araucaria augustifolia forest, in the municipality of Tijucas do Sul, State of Paraná, Brazil. Ectoparasites infested 98% of the rodents, with the highest indices of infestation found in the dry-cool season. Species that occurred in single or multiple infestations were recorded. Ectoparasite/host associations were significant (p<0.01) for Gigantolaelaps wolffsohni/Oryzomys nigripes, Polygenis pradoi/Oxymycterus sp. and Amblyopinus sp./Oxymycterus sp. The following represent new host records: Polygenis (Polygenis) tripus from Akodon serrensis and Hoplopleura sciuricola from Sciurus aestuans. New geographic records are given for two species of flea and one sucking lice.

Os cariótipos referentes a quatro machos de Alouatta fusca clamitans oriundos do Rio de Janeiro foram analisados através de técnicas de bandamento G, C e NOR. O número diplóide em todos os espécimes foi igual a 49, com a presença de três cromossomos não pareados. A comparação dos padrões de bandamento G com espécimes previamente descritos com 2n = 50 revelou a ocorrência de uma translocação do tipo Y-autossomo, modificando o sistema cromossômico de determinação sexual para o tipo múltiplo, X1X2Y/X1X1 X2X2. Os blocos de heterocromatina constitutiva se distribuíram na região pericentromérica de todos os cromossomos; segmentos intercalares e teloméricos foram visualizados em um par acrocêntrico e em outro submetacêntrico, respectivamente. As regiões organizadoras de nucléolo se localizaram no braço longo de dois pares de pequenos acrocêntricos.

The chromosome complements of four males of Alouatta fusca clamitans, caught in Rio de Janeiro State, Brazil, were analyzed by G-, C-, and NOR-banding techniques. The diploid number found was 49 in all the specimens. The presence of a heteromorphic pair of submetacentric chromosomes in the analyzed specimens, not present in males and females with 2n = 50 previously reported, and its G-banding pattern, led us to assume that this pair is involved in a Y-autosome translocation. Thus, the sex determination system appears modified to X1X1X2X2 /X1X2Y. Heterochromatic segments were found in the pericentromeric region of all the chromosomes, in the telomeric region of the short arm in pair 2, in the complete length of the short arm of pairs 5 and 6 and in the intercalary region of the long arm in pair 17. The nucleolar organizer regions were situated in the intercalary region of the long arm in two small acrocentric pairs.

The karyotype of Akodon cursor (initially identified as A. arviculoides) had been reported with chromosomal numbers 14 and 15 in the South and Southeast and 16 in Northeastern Brazil. We found the three cytotypes in a region of Southern Brazil. The G-band patterns of these specimens were the same as those from southeastern and northeastern regions. Seventeen different combinations of chromosomes due to a complex rearrangement in pair 1 and pericentric inversions in pairs 2 and 3 were identified. Seven of these combinations are new to in the literature.