The food habits and seed dispersal promoted by five didelphid marsupials, were investigated through fecal analysis in a cerrado reserve located in the central part of the Espinhaço mountain range in Minas Gerais state, southeastern Brazil. The studied species presented a remarkable constancy in their diets and just for C. philander a seasonal change in diet seems to be present with a high consumption of fruits during the wetter season. Arthropods such as hymenopterans, coleopterans and homopterans were the main food resource detected but seeds belonging to pioneer plants were found with high frequencies in samples of all didelphids. Fruits of pioneer plants belonging to the families Melastomataceae (Clidemia urceolata and Miconia holocericea) and Rubiaceae (Psychotria barbiflora and P. capitata) present high germination rates and were among the mostly consumed. In spite of the differences observed in food preferences, all of the didelphids studied must be considered effective seed dispersers of pioneer plants.

The variation in degrees of interdigitation (complexity) in cranial sutures among species of Caiman in different skull regions was studied by fractal analysis. Our findings show that there is a small species effect in the fractal dimension of cranial sutures, but most variation is accounted for by regional differentiation within the skull. There is also a significant interaction between species and cranial regions. The braincase sutures show higher fractal dimension than the facial skull sutures for all three species. The fractal dimension of nasal-maxilla suture is larger in Caiman latirostris than in the other species. The braincase sutures show higher fractal dimensions in C. sclerops than in the other species. The results suggest that different regions of the skull in caimans are under differential functional stress and the braincase sutures must counteract stronger disarticulation forces than the facial sutures. The larger fractal dimension shown by C. latirostris in facial sutures has probably a functional basis also. Caiman latirostris is known to have preferences for harder food items than the other species.Key words: cranial sutures, fractal analysis, osteology, Caiman. RESUMOAnálise comparativa da complexidade de suturas cranianas no gênero Caiman (Crocodylia, Alligatoridae)A variação no grau de interdigitação (complexidade) em suturas cranianas entre espécies de Caiman em diferentes regiões cranianas foi estudada por análise fractal. Os resultados mostram que há um pequeno efeito atribuível a diferenças interespecíficas na dimensão fractal das suturas, mas a maior parte da variação na dimensão fractal é causada por diferenças entre regiões cranianas. Há também uma interação significativa entre espécies e regiões cranianas. As suturas da caixa craniana apresentam dimensão fractal mais alta que as suturas craniofaciais nas três espécies. A dimensão fractal da sutura nasal-maxilar é maior em Caiman latirostris que nas outras espécies. As suturas da caixa craniana apresentam maior dimensão fractal em C. sclerops que nas outras espécies. Os resultados sugerem que diferentes regiões cranianas nas espécies de Caiman se encontram sob estresse funcional diferenciado. As suturas da caixa craniana precisam suportar maior força de desarticulação que as suturas craniofaciais. A maior dimensão fractal nas suturas craniofaciais de C. latirostris provavelmente é causada por uma demanda funcional. Caiman latirostris apresenta preferência por itens mais duros em sua dieta que as outras espécies.Palavras-chave: suturas cranianas, análise fractal, osteologia, Caiman. Rev. Brasil. Biol., 60(4): 689-694 690 MONTEIRO, L. R. and LESSA, L. G.

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.

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The diversity of Brazilian mammals is among the highest of the world. However this exceptional diversity is still widely unknown and great part of it is seriously threatened by human activities. In the present study we estimated species richness and relative abundance of medium and large size mammals for the region of Brasilândia de Minas, a city situated in a fragmented and poorly studied cerrado area of Minas Gerais state, Brazil. We obtained 63 records of 24 species, including eight species threatened with extinction. Our results support the hypothesis that many of the cerrado mammal species may be able to persist in fragmented agricultural landscapes. This paper shows that despite the anthropogenic disturbances detected, the studied area plays an important role in the conservation of medium and large size mammals in the cerrado biome.

We analyzed the feeding habits and the endozoochoric seed dispersal of six species of Neotropical small rodents in a riparian forest in the Cerrado biome at the central portion of Espinhaço Mountain Range, Brazil. The species presented a miscellaneous diet consuming arthropod, especially Hymenoptera (ants) and Isoptera (termites), fruits of pioneer species and vegetative parts of plants (stems and leaves). The high frequency of arthropods in the diet of all species studied reinforces its importance as a food resource for small Neotropical rodents, especially in environments with a marked seasonality, such as in the Cerrado. The number of intact seeds after gut passage and the higher germinability of the ingested seeds, compared to the control group, indicates that the studied rodents acted mainly as dispersers and not as predators of small seeds (≤ 1 mm) of pioneer species (Melastomataceae and Rubiaceae).

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Foi avaliado o estado de conhecimento atual sobre os hábitos alimentares das espécies de marsupiais didelfídeos brasileiros, analisando as informações disponíveis com relação à composição e variação de sua dieta entre biomas e comparando os resultados obtidos a partir dos principais métodos utilizados em estudos de dieta em campo. A variação sazonal de recursos parece ter forte influência na composição da dieta para a maioria das espécies estudadas, embora a maioria dos estudos seja meramente descritiva, não avaliando diretamente a disponibilidade de recursos no ambiente. Espécies com ampla distribuição geográfica podem apresentar variações na dieta entre diferentes biomas ou habitats. Apesar do número de estudos sobre os marsupiais brasileiros ter aumentado expressivamente nas últimas três décadas, informações fundamentais sobre os hábitos alimentares para a maioria das espécies são ainda escassas ou inexistentes. Palavras-chave: Didelphimorphia; Didelphidae; ecologia alimentar; dieta. ABSTRACT FOOD HABITS OF BRAZILIAN DIDELPHID MARSUPIALS: ANALISYS OF CURRENT STATE OF KNOWLEDGE. We evaluated the current knowledge on the feeding habits of Brazilian didelphids, considering the available information on changes in diet composition between biomes. We also compared the results obtained from the principal methods used in studies of diet in the field. Seasonal variation in resource availability appears to have a strong influence on the composition of the diet for most species, although most studies are merely descriptive, not directly assessing the availability of resources in the environment. Species with wide geographical range may vary their diet between different habitats or biomes. Despite the increase in the number of studies with the Brazilian marsupials over the last three decades, fundamental information on dietary habits for most species is scarce or nonexistent.