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34 result(s) for "Zeballos, Horacio"
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Description of a New Genus and Species of Semi-Aquatic Rodent (Cricetidae, Sigmodontinae, Ichthyomyini) from the Southern Peruvian Andes
We describe a new genus and species of the tribe Ichthyomyini (Rodentia: Sigmodontinae) based on three specimens collected in Machupicchu, Cusco, in the southern Peruvian Andes. Our study includes a comprehensive morphological analysis of 201 specimens representing all recognized species, employing multivariate statistics (principal component analysis) of external and cranial measurements, as well as phylogenetic methods. We used maximum parsimony for morphological data and concatenated molecular datasets (Cytochrome b [17 species], IRBP [15 species], and RAG1 [11 species]) analyzed via maximum likelihood and Bayesian inference. The new genus and species exhibit an allopatric distribution relative to other Ichthyomyini and are distinguished by the following combination of traits: dull slate-gray dorsal fur, lighter ventrally without contrast to the dorsum; incomplete philtrum; vestigial pinna concealed within head fur; long, broad hindfeet with a well-developed fringe of stiff hairs and brown soles; laterally compressed tail exceeding head-body length; type 1 carotid circulation pattern; absence of the orbicular apophysis of the malleus; presence of posteroloph and posterolophid in M1, M2, m1, and m2; unilocular hemiglandular stomach (non-reduced).
Systematics and diversification of the Ichthyomyini (Cricetidae, Sigmodontinae) revisited: evidence from molecular, morphological, and combined approaches
Ichthyomyini, a morphologically distinctive group of Neotropical cricetid rodents, lacks an integrative study of its systematics and biogeography. Since this tribe is a crucial element of the Sigmodontinae, the most speciose subfamily of the Cricetidae, we conducted a study that includes most of its recognized diversity (five genera and 19 species distributed from southern Mexico to northern Bolivia). For this report we analyzed a combined matrix composed of four molecular markers ( RBP3 , GHR , RAG1 , Cytb ) and 56 morphological traits, the latter including 15 external, 14 cranial, 19 dental, five soft-anatomical and three postcranial features. A variety of results were obtained, some of which are inconsistent with the currently accepted classification and understanding of the tribe. Ichthyomyini is retrieved as monophyletic, and it is divided into two main clades that are here recognized as subtribes: one to contain the genus Anotomys and the other composed by the remaining genera. Neusticomys (as currently recognized) was found to consist of two well supported clades, one of which corresponds to the original concept of Daptomys . Accordingly, we propose the resurrection of the latter as a valid genus to include several species from low to middle elevations and restrict Neusticomys to several highland forms. Numerous other revisions are necessary to reconcile the alpha taxonomy of ichthyomyines with our phylogenetic results, including placement of the Cajas Plateau water rat (formerly Chibchanomys orcesi ) in the genus Neusticomys ( sensu stricto ), and the recognition of at least two new species (one in Neusticomys , one in Daptomys ). Additional work is necessary to confirm other unanticipated results, such as the non-monophyletic nature of Rheomys and the presence of a possible new genus and species from Peru. Our results also suggest that ichthyomyines are one of the main Andean radiations of sigmodontine cricetids, with an evolutionary history dating to the Late Miocene and subsequent cladogenesis during the Pleistocene.
New record of Marmosa (Stegomarmosa) andersoni Pine, 1972 (Didelphimorphia, Didelphidae), a rare and endemic Peruvian marsupial
Marmosa ( Stegomarmosa ) andersoni Pine, 1972 is one of the rarest members of the genus Marmosa . This species is endemic to southeastern Peru and currently known from only 3 close localities in Cusco. Herein we report a new record for the species from Pasco, which extends its geographic distribution by 360 km and represents its northernmost record
Poachers alter mammal abundance, seed dispersal, and seed predation in a neotropical forest
We evaluated the hypothesis that poachers reduce the abundance of herbivorous mammals, and that this, in turn, alters seed dispersal, seed predation, and seedling recruitment for two palms (Attalea butyraceae and Astrocaryum standleyanum) in central Panama. Using physical evidence left by poachers and interviews with forest guards, we quantified poaching intensity for eight forest sites. We quantified mammal abundance using transect counts and small-mammal traps. Abundance was inversely related to poaching intensity for 9 of 11 mammal species (significantly so for 5 species), confirming the first component of the hypothesis. The outcome of interactions among seeds, mammals, and beetles also varied with poaching intensity. Nonvolant mammals were the only seed-dispersal agents, and rodents and beetles were the only seed predators. We quantified seed fate by examining the stony endocarps that encase the seeds of both palms. The large, durable endocarps were located easily on the forest floor and bear characteristic scars when a rodent or beetle eats the enclosed seed. The proportion of seeds dispersed away from beneath fruiting conspecifics was inversely related to poaching intensity, ranging from 85% to 99% at protected sites where mammals were abundant and from 3% to 40% at unprotected sites where poachers were most active. The proportion of dispersed seeds destroyed by beetles was directly related to poaching intensity, ranging from 0% to 10% at protected sites and from 30% to 50% at unprotected sites. The proportion of dispersed seeds destroyed by rodents was inversely related to poaching intensity, ranging from 85% to 99% at protected sites and from 4% to 50% at unprotected sites. Finally, seedling densities were directly related to poaching intensity. There was no single relationship between poaching intensity and the biotic interactions that determine seedling recruitment. The net effect of poaching on seedling recruitment can be determined only empirically. For these palms, seedling densities were directly related to poaching intensity.
First record of the Andean-mountain cavy Microcavia niata (Caviidae, Rodentia) from Peru
We report for the first time the presence of the Andean-Mountain Cavy, Microcavia niata, in Peru, being a new genus and species for Peruvian wildlife. We base our report on two specimens found in the highlands of Tacna, southwestern Peru.
Range extension of the rare Peruvian fish-eating rat Neusticomys peruviensis (Rodentia: Cricetidae) in Peru
Neusticomys peruviensis (Musser & Gardner 1974) is a semi aquatic rodent which belongs to the Ichthyomyini Tribe. It is an endemic species of Peru, previously known for three specimens: type specimen from Balta, another specimen from Rio Shesha, both from Ucayali department; and the third specimen from Pakitza (Madre de Dios department). We captured an additional specimen in Cusco Department. Its geographic distribution extends 84.15 km south of the previously known distribution range. This suggest that this species would have a broader distribution. More detailed studies are needed to know the ecology and distribution of these rodents.
Small vertebrates in the spectacled bear’s diet (Tremarctos ornatus Cuvier, 1825) in the north of Peru
There have been numerous studies about Spectacled bear´s diet, however little is known about the small vertebrates it consumes. This study present nine vertebrate species (seven rodent and two birds) as preys of the Spectacled bear, based on the analysis of six feces collected from two locations Upa (Amazonas) and Lagunas Arreviatadas (Cajamarca) in northern Peru. Six of these records were new food items and a new family Caviidae. Vertebrates were found only in the Upa location. Additionally a sampling of small non flying mammals was conducted in there. Our results suggest that the Spectacled bear would be a generalist species. It prefers plants, however if it finds vertebrates in the environment, it could feed on them.
Nuevos registros de murciélagos para el Perú
Presentamos el primer registro de tres mamíferos pequeños voladores para el Perú en base a especímenes colectados entre 2007 y 2014. Estos son: Eumops glaucinus, en la selva baja del centro del Perú; Molossus bondae en el bosque tropical del Pacífico, y Promops nasutus en bosques montanos del sureste. Los nuevos registros incrementan la diversidad de mamíferos del Perú a 579 especies.
importance of forest patch networks for the conservation of the Thorn-tailed Rayaditos in central Chile
Conservation of forest birds in fragmented landscapes requires not only determining the critical patch characteristics influencing local population persistence but also identifying patch networks providing connectivity and suitable habitat conditions necessary to ensure regional persistence. In this study, we assessed the importance of patch attributes, patch connectivity, and network components (i.e., groups of interconnected patches) in explaining the occupancy pattern of the Thorn-tailed Rayadito (Aphrastura spinicauda), a forest bird species of central Chile. Using a daily movement threshold distance, we identified a total of 16 network components of sclerophyllous forest within the study area. Among those components, patch area and vegetation structure-composition were important predictors of patch occupancy. However, the inclusion of patch connectivity and component size (i.e., the area of a network component) into the models greatly increases the models' accuracy and parsimony. Using the best-fitted model, a total of 33 patches were predicted to be occupied by rayaditos within the study area, but such occupied patches were distributed in only six network components. These results suggest that persistence of rayaditos in central Chile requires the maintenance of large single patches and patch networks providing habitat and connectivity.
Primer registro del ratón colombiano del bosque Chilomys instans (Cricetidae: Rodentia) en Cajamarca: actualizando el listado de mamíferos del Perú
El roedor Chilomys instans (Thomasomyini, Cricetidae) es una especie común en la comunidad de mamíferos que habita los Andes del Norte en Sudamérica. Aquí presentamos el primer registro de la especie para el Perú, en base a la revisión morfológica de tres ejemplares colectados en el departamento de Cajamarca (Andes del Centro). Se presentan comentarios sobre la taxonomía de C. instans e información sobre su historia natural. La amplia distribución del género Chilomys en los Andes pone de manifiesto la necesidad de realizar la revisión taxonómica de éste género para esclarecer los límites de las especies que la conforman.