Small mammals (Didelphimorphia and Rodentia) from southwestern Buenos Aires Province, Argentina: taxonomy and distribution. Species of small mammals from southwestern Buenos Aires Province range within a wide variety of habitats: herbaceous (Pampean District), shrubs (Monte District), steppes, and xerophytic woodlands (Espinal District). Their natural history is still poorly known. In this paper we make a synthesis of the taxonomy and distribution of the marsupials (Marmosinae) and rodents (Sigmodontinae) of southwestern Buenos Aires Province. Distributional records and taxonomical information were obtained from field survey, analyses of raptor pellets, revision of specimens housed in collections in Argentina, and literature. Between Sierra de la Ventana (38° S) and the Río Negro (41° S) occur two species of marmosines and 14 of sigmodontine rodents. Some of these species show a restricted distribution (e.g., Phyllotis xanthopygus, endemic for Sierra de la Ventana), and others are widespread (e.g.Akodon azarae or Calomys musculinus) across different phytogeographic units. A cluster analysis at local scale shows an ordination of small mammal assemblages with the topology (Sierra de la Ventana + Southern Atlantic Coast) (Espinal + Monte). The zoogeographic unicity of the Monte in the study area is evidenced by two sigmodontines, Akodon iniscatus and Oligoryzomys longicaudatus. The micromammal assemblage of Sierra de la Ventana may be characterized as pampasic. The wide distribution of A. azarae and C. musculinus may reflect the anthropic activities developed during the last century. These activities on shrub steppe have certainly diluted the original zoogeographic boundaries and allowed the dispersion of opportunistic sigmodontine species.
Morphological adaptations of the tongue of Desmodus rotundus (Chiroptera: Phyllostomidae) related with their feeding habits. An analysis of the external morphology and histomorphology of the tongue, as well as an histochemical analysis of the glands of Desmodus rotundus, are here presented with the purpose of establishing a correlation between these structures and the feeding habits of this species. In the lingual surface they have the typical filiform papillae modified to different degrees of keratinization, and there are fungiform-like papillae in less amount. The intrinsic musculature and the presence of lynphocitary infiltration are described; the presence of important nervous packages was observed.
Chemical characteristics of salt licks and feeding habits of mountain tapir (Tapirus pinchaque) in the central Andes of Colombia. The chemical composition of salt licks and the diet of the mountain tapir (Tapirus pinchaque) were studied in the upper montane rain forests (2900–3700 m), in the Parque Regional Natural Ucumari and Parque Nacional Natural Los Nevados, Colombia. We collected water samples from the salt licks, 28 feces and voucher specimens of plants with tapir browsing sign. The chemical analysis of the water from salt licks showed higher concentrations of Na, N-NH4 y N-NO3 when compared to the water of a nearby stream used as control. The nitrogen of the water at the salt lick is probably being fixed by Nostoc, a Cyanobacteria associated with Gunnera manicata and G. magnifolia, two plants located in the upper part of the rocky cliff from where the water drains to the salt lick. It is likely that the tapirs are drinking these waters to complement their diet, especially in an environment like tropical montane forests where nitrogen is in low concentration. A total of 35 plant species showed browsing signs. The plant families that the tapir consumed the most were ferns (seven species), Melastomataceae (six species) and Rubiaceae (five species). In the feces there were mostly leaves and twigs and no fruits or seeds. Germination experiments should be carried out to determine if the mountain tapir is a seed dispersal as suggested in Ecuador.
New records of Glironia venusta and Didelphis albiventris (Didelphimorphia) from Peru. We report a new record of Glironia venusta from Peru. The new locality is the fifth record for the country, and the 18th for all of South America. Also, we extend the distribution of Didelphis albiventris to the Amazon Basin of northeastern Peru. The addition of these species to the biota of Iquitos reaffirm that this is one of the localities having the most species-rich marsupial fauna in the New World.