Volumen y Número: Vol. 9

Ejemplar de la especie extinta Monachus tropicalis (Carnivora, Phocidae) en el Museo de La Plata (Argentina)

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Se confirma la presencia de un ejemplar adulto de la especie extinta Monachus tropicalis, Gray 1850, en la colección mastozoológica del Museo de La Plata (Argentina) sobre la base del análisis morfológico cráneo-dentario del mismo. A partir de los datos de colección que figuran en el libro de entradas y de la investigación bibliográfica realizada se infiere que el mismo fue colectado en una expedición realizada en el año 1886 a las islas Triángulo, Golfo de Méjico.

A specimen of the extinct species Monachus tropicalis (Carnivora, Phocidae) in the La Plata Museum (Argentina). The identification of an adult specimen of the extinct species Monachus tropicalis, Gray 1850, is confirmed based upon the analysis of its dentition and skull morphology. From the collection data stated in the catalogue as well as by bibliographical research we infer that the specimen was collected by an expedition carried out in 1886 to the Triangle Islands, Gulf of México.

La fauna pleistocena de la Formación Toropí en la provincia de Corrientes (Argentina)

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En el presente trabajo se dan a conocer los restos fósiles asignables a seis taxones de mamíferos exhumados de la Formación Toropí (Pleistoceno tardío – Holoceno temprano), en la localidad de Lavalle, provincia de Corrientes, Argentina. Estos fueron clasificados como Pampatheriidae: Pampatherium typum; Glyptodontidae: Glyptodon sp.; Mylodontidae: Scelidodon sp.; Toxodontidae: Toxodon sp.; Gomphotheriidae: Stegomastodon aff. S. platensis y Cervidae: Antifer aff. A. ensenadensis. Asimismo, se lleva a cabo una breve descripción de los restos y se mencionan los principales rasgos estratigráficos, paleobiogeográficos y paleoambientales de cada taxón. El conjunto de los restos exhumados permite inferir, para el Pleistoceno medio – Holoceno temprano de esta parte de la Mesopotamia, condiciones climáticas similares a las desarrolladas en el mismo lapso de tiempo en la región Pampeana. Bioestratigráficamente, es significativo el hallazgo de Scelidodon y Antifer aff. A. ensenadensis, ya que se constituyen en la primera cita para la Argentina de estos taxones en sedimentos más recientes que el Ensenadense.

The Pleistocene fauna from the Toropí Formation (Corrientes Province, Argentina). In this paper we report the remains of six fossil mammals from the Toropí Formation (late Pleistocene – early Holocene), Corrientes province (Argentina). These remains were classified as Pampatheriidae: Pampatherium typum; Glyptodontidae: Glyptodon sp.; Mylodontidae: Scelidodon sp.; Toxodontidae: Toxodon sp.; Gomphotheriidae: Stegomastodon aff. S. platensis y Cervidae: Antifer aff. A. ensenadensis. In this way, the rests are described and their stratigraphic and paleobiogeographic distribution is established. The taxa here described show similar climatic conditions between this area and the Pampean region during middle Pleistocene – early Holocene. Biostratigraphically, it is important to remark the first record in Argentina of Scelidodon and Antifer aff. A. ensenadensis in Lujanian sediments.

Sprainting sites of the Neotropical otter, Lontra longicaudis, in an Atlantic Forest area of southern Brazil

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This work was carried out in Reserva Volta Velha, an Atlantic Forest area in Itapoá, Santa Catarina State, in southern Brazil, from September 95 to March 97. The objectives were to tipify holts of the Neotropical otter [Lontra longicaudis (Olfers, 1818)] and determine the use of sprainting sites. Monthly, we went by boat along Saí-Mirim, Braço do Norte, and Volta Velha rivers looking for otter holts, scats and footprints. The results obtained indicate that on the studied rivers, characterized by presence of silty and/or sandy bottom and absence of rocks, otters use holts among tree roots, mainly where river banks are high. In this type of environment, dense vegetation protects holt structure against erosion and high banks represent a protection against flooding. The present work corroborates the importance of the alluvial dense ombrophyllous forest to keep habitat conditions favorable to the Neotropical otter.

Karyotypes of Brazilian representatives of genus Zygodontomys (Rodentia, Sigmodontinae)

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In this article we are reporting two cytotypes found in representatives of Zygodontomys genus trapped in two localities of Brazilian Amazon. From the locality of Surumú (Roraima) were analyzed 12 individuals (cytotype 1) which showed 2n = 86 / FN = 96–100, presenting the two largest pairs (1 and 2) as subtelo-submetacentrics, 4 or 5 medium to small biarmed pairs, the remainder being acrocentric. In Tartarugalzinho (Amapá) 7 specimens which displayed 2n = 84 / FN = 96–98 (cytotype 2) were caught. In both cytotypes the sexual pair is composed by a large submetacentric X chromosome and a median subtelocentric Y chromosome. By G-banding the largest pairs as well as the sex chromosomes could be identified. The C-bands occurred at the centromere of the majority of the autosomes and the short arm of the X and the whole Y chromosomes were heterochromatic. The NOR-bands were prevalently seen at the short arm of one medium and one small acrocentric pairs. Comparing the individuals studied in Brazil with those reported in Venezuela is observed that, although the same or similar diploid numbers, the morphology of the chromosomes of these taxa is quite different, the karyotypes of the specimens from Brazil having a smaller number of biarmed elements.The sexual pair is distinct also, the difference basically concerning to the size of the Y chromosome. Whether these karyotype differences may correspond to different morphological taxa is a subject that deserves further investigations.

Chave artificial para a identificação de Molossideos brasileiros (Mammalia, Chiroptera)

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O crescente número de trabalhos de campo sobre morcegos no Brasil e a importância deste grupo para a saúde pública evidencia que há a necessidade de chaves consistentes para identificar as espécies. Os molossídeos compõem a segunda família mais rica em espécies de morcegos ocorrendo no Brasil e este trabalho fornece uma chave de identificacação para as espécies deste grupo. Nós reconhecemos 24 espécies presentes no Brasil, incluindo Eumops maurus e E. dabbenei, cuja ocorrência é presumível e E. patagonicus na qual consideramos como espécie válida. Nós também tecemos alguns comentários taxonômicos.

Artificial key for identification of Brazilian molossids (Mammalia, Chiroptera). Increased fieldwork on bats in Brazil and the importance of these animals for public health evidence a need for consistent keys to identify species. Molossid bats are the second most species-rich family of bats occurring in Brazil. This paper provides an artificial key to species of free-tailed bats. We recognize 24 species for Brazil, including Eumops maurus, E. dabbenei, and Molossus currentium, presumably occurring in the country, and E. patagonicus, which we consider valid. We also provide some taxonomic comments.

Clave artificial para la identificación de los molósidos brasileños (Mammalia: Chiroptera). El creciente número de trabajos de campo sobre murciélagos en Brasil y la importancia de este grupo para la salud pública evidencian la necesidad de claves consistentes para la identificación de las especies. Los molósidos constituyen la segunda familia más diversa de murciélagos del Brasil, por lo que en este trabajo se presenta una clave de identificación para las especies de este grupo. Reconocemos 24 especies presentes en Brasil, incluyendo Eumops maurus, E. dabbenei y Molossus currentium cuya ocurrencia es probable, y E. patagonicus la cual consideremos como una especie válida. Se incluyen también algunos comentarios taxonómicos.

Lista comentada de los mamíferos de la Reserva de Biósfera Mar Chiquita, provincia de Buenos Aires, Argentina

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En este trabajo se presenta una lista de los mamíferos de la Reserva de Biósfera Mar Chiquita (provincia de Buenos Aires, Argentina) aportando información sobre sus relaciones con el hábitat. Se utilizó la información proveniente de muestreos de campo y de revisiones bibliográficas. Se registraron 28 especies de mamíferos agrupados en siete órdenes. El 86% correspondió a especies autóctonas y el 14% a especies introducidas. Los roedores constituyeron el grupo más representativo con un total de 16 especies. Los ambientes que presentaron las mayores riquezas específicas fueron: pastizales halófilos altos, praderas saladas, campos altos de pastoreo, cortaderales, bañados y albufera. La diversidad de ambientes que ofrece este ecosistema único permite la coexistencia de mamíferos que presentan un amplio espectro de estrategias ecológicas y características de historias de vida.

Mammals from Mar Chiquita Biosphere Reserve, Buenos Aires Province, Argentina. A checklist of mammals from Mar Chiquita Biosphere Reserve is presented, providing insights on their habitat relationships. The sources of information are field data and bibliographic research. We recorded 28 mammalian species belonging to seven orders. From the total, 86% corresponded to native species and 14% were introduced species. Rodents were the most representative group with 16 species. Halophitic tall and short grasslands, uplands, wetlands, and grasslands of Cortaderia selloana showed the highest species richness. The habitat diversity offered by this unique ecosystem allows the coexistence of mammals characterized by a wide spectrum of ecological strategies and life history traits.