Abstract The similarity between parasites communities’ decay with distance and its analysis may explain important ecological process such host dispersion. Patagonia is inhabited by two armadillo species, Chaetophractus villosus and Zaedyus pichiy. In this study we describe and analyze the variation on helminth fauna of these armadillos in Patagonia compared with northern localities described in previous studies. A total of 49 armadillos were collected in Patagonia. Quantitative descriptors of parasite ecology were calculated and community structure of helminths was analyzed following the central-satellite species hypothesis. The parasite richness in Patagonia decreases almost 50% in both armadillos. Zaedyus pichiy present the same central species in Patagonia as in northern localities. For C. villosus central-satellite species analysis could not be applied. The loss of some helminths in Z. pichiy could be the result of lower temperatures or the absence of intermediate arthropods hosts. But in C. villosus the absence of some helminths with Patagonian distribution could be explained by its recent dispersion in Patagonia. Trichohelix tuberculata still being the only helminth in C. villosus introduced population of Tierra del Fuego.

Abstract The pichi (Zaedyus pichiy; Cingulata: Chlamyphoridae) is an armadillo whose ectoparasite fauna is composed of ticks and fleas. Fleas were collected from 218 pichis in southern Mendoza, Argentina, in summer and winter of 2015 and 2016. Prevalences were analyzed and differences in the intensities of the total number of fleas related to host (age, sex, weight, size and physical condition) and environment-related (seasonality and year) factors evaluated. Phthiropsylla agenoris was the only species found. Intensities of fleas were higher in 2015, in juveniles, and in males. Individuals with poor physical condition were more parasitized than those with good or normal body condition. The main explanatory variable was sampling year. This factor was directly associated with precipitation. The extreme conditions and heavy rains during the El Niño event in 2015/2016 led to environmental changes that seem to have severely affected the life cycle of fleas.

ABSTRACT The aim of this work was to obtain the first estimates of survival rates (S), capture probability (p) and life expectancy for armadillos in South America by analyzing capture-mark-recapture data obtained from a population of Chaetophractus vellerosus (Gray, 1865) located in Magdalena, Buenos Aires, Argentina. From June 2006 to June 2011, we conducted 16 field surveys that resulted in 365 capture events of 152 adult C. vellerosus. For the survival analysis we used a Cormack-Jolly-Seber (CJS) modelling framework. Interannual variation in S made an important contribution to overall variation in the survival rate of C. vellerosus. The average life expectancy for females and males after attaining sexual maturity was estimated at 1.70 and 1.65 years respectively. The period of lowest survival probability was associated with dry seasons that might have affected the availability of food. This study provides the first estimates of demographic parameters for xenarthrans in South America.

During the last decades, the Pampas Region of Argentina has witnessed an expansion of the croplands at the expense of grasslands and pastures. As a result of no-till system, after harvesting the region shows large areas with stubbles. The aim of this study is to describe the assemblage of land birds and compare species richness and abundance at the community guild levels in crop and livestock fields during two contrasting periods of the year, when croplands remains at stubbles stage. Twenty-five sites were selected and in each one four samplings were conducted: two in spring-summer and two in autumn. In each site and each sampling, two crop and two livestock fields were chosen, totalling 392 fields. Birds were recorded in each field using a linear transect of 700 m by 100 m. Seventy-five species were recorded. Livestock fields supported greater species richness than crop fields throughout the study, provided by highest insectivore species richness. In spring-summer, there was a higher abundance in livestock fields, mainly of insectivore birds. There were not significant differences in species richness and abundance of granivorous birds between land uses, even though in autumn there was a sharp differential use of crop fields by the granivorous species Zenaida auriculata, which accounted for 36% of total abundance in crop fields during that period. The results show that there is an impoverishment of the bird assemblage in crop fields with regard to livestock fields and it can be expected that these trends will be accentuated as long as the substitution between these different land uses deepens.

En las últimas décadas, los agroecosistemas de la Región Pampeana en Argentina han sido objeto de cambios en los patrones de uso de la tierra caracterizados por la expansión de la agricultura en detrimento de pastizales y pasturas. Como resultado de la amplia adopción de la práctica de siembra directa, luego de la cosecha se registran en algunas zonas extensas áreas cubiertas con rastrojos. El objetivo de este trabajo es describir el ensamble de aves terrestres y comparar la riqueza específica y la abundancia a nivel comunitario y gremial de lotes agrícolas y ganaderos durante dos períodos contrastantes del año en los cuales los lotes agrícolas se encuentran en rastrojo. Se seleccionaron 25 sitios que fueron visitados en cuatro oportunidades: dos veces en primavera-verano y dos veces en otoño. En cada sitio y muestreo se eligieron dos lotes agrícolas y dos ganaderos independientes (392 lotes en total). En cada lote se registraron las aves en una transecta lineal de 700 m de largo y 100 m de ancho. Se registró un total de 75 especies. Los lotes ganaderos tuvieron una riqueza específica mayor que los agrícolas a lo largo de todo el estudio, aportada por una mayor riqueza de aves insectívoras. En primavera-verano hubo una mayor abundancia de aves en lotes ganaderos, particularmente de aves insectívoras. No hubo diferencias en la riqueza y la abundancia de aves granívoras entre lotes, aunque en el otoño se registró un marcado uso diferencial de los lotes agrícolas por parte de la especie granívora Zenaida auriculata, que acumuló el 36% de la abundancia en esos lotes agrícolas durante ese período. Los resultados muestran un empobrecimiento del ensamble de aves en lotes agrícolas con respecto a los ganaderos; es de esperar que estas tendencias se acentúen en la medida que se profundice la sustitución entre estos usos de la tierra.

The aim of this study was to analyze the parasitic fauna of a population of Chaetophractus vellerosus from Magdalena, Buenos Aires province, Argentina, by parasitological analysis. We evaluated the influence on the parasitic dynamics of different host parameters -age, sex, height and weight- as well as seasonality, vegetation and human impact. Oocysts of 2 species of Eimeria (Protozoa-Coccidea) and eggs of Aspidodera sp. Trichostrongylina, Ancylostoma sp. and Trichuris sp. (Nematoda) were found. Eimeria sp. and Aspidodera sp. were the most prevalent parasites, and Ancylostoma sp. was the lowest prevalent. Parasite loads of coccideans were higher in hosts young. Parasite loads of Trichuris sp. were higher in males. Only Trichostrongylina had greater loads in specimens with poor body condition. Trichostrongylina and Eimeria sp. were most prevalent in summer, while Aspidodera sp. was in winter. Neither vegetation nor human impact influenced in parasitic loads. This study enabled us to know the parasitic fauna of a population of C. vellerosus (Dasypodidae) in Argentina through coproparasitological analysis, and monitor it for 4 consecutive years.

El objetivo de este trabajo fue analizar la fauna parasitaria de una población de Chaetophractus vellerosus de Magdalena, provincia de Buenos Aires, Argentina, mediante análisis coproparasitológicos. Se evaluó la influencia de distintos parámetros del hospedero -edad, sexo, talla y peso- estacionalidad, cobertura vegetal y el impacto antrópico sobre la dinámica de la estructura parasitaria. Se hallaron ooquistes de 2 especies de Eimeria (Protozoa-Coccidea) y huevos de Aspidodera sp., Trichostrongylina, Ancylostoma sp. y Trichuris sp. (Nematoda). Los parásitos de mayor prevalencia fueron Eimeria sp. y Aspidodera sp., el de menor, Ancylostoma sp. Las cargas parasitarias de los coccidios fueron mayores en los hospederos juveniles; las de Trichuris sp. fueron mayores en los machos. Sólo los Trichostrongylina tuvieron mayores cargas en los hospederos con mala condición corporal. Trichostrongylina y Eimeria sp. fueron más prevalentes en verano, mientras que Aspidodera sp. lo fue en invierno. Ni la cobertura vegetal ni el impacto antrópico influenciaron sobre las cargas parasitarias. El presente estudio permitió conocer la fauna parasitaria de una población de C. vellerosus (Dasypodidae) en Argentina mediante el análisis coproparasitológico y su seguimiento durante 4 años consecutivos.

This contribution presents new data about the natural history of the Dasypus hybridus (Desmarest, 1804) (Mammalia, Xenarthra, Dasypodidae). A seasonal monitoring using the capture and release method was performed over the course of three years in a 100 ha of four cattle farms in the Buenos Aires province, Argentina. Data were collected on food habits, space and time use, behavior, thermoregulation, population data, and morphology. A total of 71 captures were made. The main food items recorded were plant matter, ants and coleopterans, and did not occur seasonal differences in food habits. Dasypus hybridus concentred their activities during daytime, and were recorded a low frequency of activities during cold seasons (fall and winter). The long-nosed armadillo prefer humid soils and grasslands with high vegetation cover, and selected forest to refuge. The southern long-nosed armadillo were asocial. Rectal temperature was positively correlated with environmental temperature. The sex proportion was near to one, and no sexual dimorphism was observed. In general, the results of this study are in agreement with previous observations of other species of the same genera, but is necessary to highlight the trend observed in food habits and thermoregulatory strategy. This work provides new information about different aspects of a poor studied species that occur in a habitat subjected to high pressure to modification and use.

En este trabajo se presentan nuevos aportes sobre la historia natural de la mulita pampeana Dasypus hybridus (Desmarest, 1804) (Mammalia, Xenarthra, Dasypodidae). Los estudios de campo fueron llevados a cabo en 100 ha de cuatro establecimientos agropecuarios de la provincia de Buenos Aires, Argentina. Durante tres años se realizó un muestreo estacional de armadillos por captura y liberación. Se obtuvieron datos de hábitos alimentarios, uso del espacio y del tiempo, comportamiento, termorregulación, datos poblacionales y morfológicos. Se realizaron 71 capturas. En la dieta el ítem principal registrado fue material vegetal, seguido por hormigas e insectos coleópteros; no se observó una diferencia estacional en los hábitos alimentarios. La actividad de las mulitas se concentra durante el día, existió una baja en la frecuencia de observación durante las estaciones frías (otoño e invierno). La mulita pampeana prefiere suelos húmicos, terrenos altos y pastizales densos y altos; asimismo seleccionan los montes para refugiarse. Son individuos asociales. La temperatura rectal mostró correlaciones positivas con la temperatura ambiente. La proporción de sexos fue cercana a uno y no se observó dimorfismo sexual. Los resultados obtenidos concuerdan parcialmente con lo observado para otras especies del género, destacando las tendencias observadas en los hábitos alimentarios y en la estrategia termorregulatoria. Este trabajo representa un aporte en varios aspectos de una especie poco estudiada en una zona bajo importantes presiones de uso y modificación de hábitat.

In this paper we analyze the distribution of extant armadillos species in the Buenos Aires province. The information comes from fieldwork, literature and collections. The analyses contain temporal and spatial aspects. We obtained 401 georeferenced records from seven species. Dasypus hybridus and Chaetophractus villosus are the most common and widely distributed armadillos. C. villosus appears to be facilitated by new agricultural practices and D. hybridus shows an increase in habitat use. A movement was registered for Zaedyus pichiy in the southeast of the province, which can be explained by changes in climate conditions. For Chlamyphorus truncatus this review shows the need for further studies since its distribution area is being intensely degraded. The only extinct species, Tolypeutes matacus, probably disappeared due to climatic and environmental changes. Dasypus novemcinctus appeared in the province few years ago, in the ecoregion Delta e Islas del Paraná. The presence of Euphractus sexcinctus, Cabassous tatouay and Dasypus septemcinctus has not been verified. The history of armadillo's distribution presented in this paper reflects climate and environmental changes. We believe these are key taxa, and the monitoring of these species will allow us to observe and interpret trends related to the use and modification of the environment as well as the conditions of temperature and precipitation.

En este trabajo se analiza la distribución de las especies actuales de armadillos registradas en el territorio de la provincia de Buenos Aires. La información proviene de trabajos de campo, revisión bibliográfica y colecciones de museo. Se analizan aspectos temporales y espaciales. Se obtuvieron 401 registros georreferenciados para siete especies. Dasypus hybridus y Chaetophractus villosus son los armadillos más comunes y ampliamente distribuidos en la provincia. C. villosus parece estar siendo favorecida por las nuevas prácticas agrícolas y D. hybridus muestra una ampliación en el uso del hábitat. Para Zaedyus pichiy se registraron cambios en la distribución en la zona sureste de la provincia, cuya explicación más consensuada son los cambios en las condiciones climáticas. Para Chlamyphorus truncatus esta revisión dejó ver la necesidad de realizar estudios, ya que la zona en donde se distribuye está siendo intensamente degradada. La única especie actual extinta, Tolypeutes matacus, probablemente haya desaparecido por cambios climático-ambientales. Dasypus novemcinctus ha ingresando en la provincia hace pocos años, registrándose en la Ecorregión Delta e Islas del Paraná. No se ha podido verificar la presencia de Euphractus sexcinctus, Cabassous tatouay y Dasypus septemcinctus. La historia de la distribución de los armadillos presentada en este trabajo sugiere que el registro producido durante los últimos años refleja cambios climático-ambientales. Así, el seguimiento de estos taxones permitirá observar e interpretar tendencias en lo que se refiere al uso y modificación del ambiente como así también en las condiciones de temperatura y precipitación, tan urgentes debido al cambio climático global.

We describe the structure and location of nests built by Oligoryzomys sp. and Holochilus brasiliensis in eastern Entre Ríos Province, Argentina. Nests were associated with water bodies. Nests of Oligoryzomys sp. averaged 18 cm length, 8 cm width, and 10 cm height and were found at elevated sites, while nests of H. brasiliensis were a few centimetres above water surface and had an ellipsoid shape with a mean size of 22.5 cm length, 13 cm width, and 18.7 cm height. A seasonal nest building pattern was observed that might indicate that these species construct their nests during spring and summer for breeding. Knowing the biology of these potential pest species of economic and public health importance in a natural environment will help defining an effective control program.

Se describe la estructura y ubicación de los nidos de Oligoryzomys sp. y Holochilus brasiliensis en el este de la provincia de Entre Ríos, Argentina. Los nidos se hallaron asociados a cuerpos de agua. Los nidos de Oligoryzomys sp. se encontraron en sitios elevados, su tamaño medio fue de 18 cm de largo, 8 cm de ancho y 10 cm de alto. Los nidos de H. brasiliensis se localizaron a unos pocos centímetros sobre la superficie del agua, tenían una forma elipsoidal con medias de 22.5 cm de largo, 13 cm de ancho y 18.7 cm de alto. Se observó un patrón estacional en su construcción; esto podría indicar que estas especies construyen sus nidos durante la primavera y el verano para albergar sus crías. Estas especies tienen importancia sanitaria y económica por lo cual es importante conocer su biología en ambientes naturales para establecer un adecuado programa de control.

Studies on the parasite fleas of Argentinean xenarthrans are scarce. This report describes new species of fleas that parasitize armadillos of Buenos Aires Province, Argentina. Polygenis (Polygenis) platensis (Rhopalopsyllidae) was collected from Chaetophractus vellerosus, and Tunga penetrans (Tungidae) from Chaetophractus villosus and Dasypus hybridus. Polygenis (P.) platensis constitutes the first record for dasipodids. This study extends the distribution of T. penetrans and cites two new parasite-host associations.

Los estudios realizados sobre las pulgas parásitas de xenartros argentinos son escasos. Esta contribución da a conocer nuevas especies de pulgas que parasitan a dasipódidos en la provincia de Buenos Aires, Argentina. Polygenis (Polygenis) platensis (Rhopalopsyllidae) se halló en Chaetophractus vellerosus, y Tunga penetrans (Tungidae) en Chaetophractus villosus y Dasypus hybridus. El hallazgo de P. (P.) platensis constituye el primer registro para dasipódidos. Se amplió la distribución conocida de T. penetrans y se citan dos nuevas asociaciones parásito-hospedador.

The study area is located in the middle-east of Entre Ríos; fitogeographically, the region is included in the Pampean Province, with relicts of the nearest Espinal Province and influenced by the Paranaese Province through the gallery forest of the streams. Eight field works were carried out (including trapping, owls pellets analysis, observation transects, indirect evidences, interviews and collection of vegetal species). Seven vegetal associations were detected: crop field, pasture, shrubland, xerophilic forest, gallery forest and exotic forest. In these associations there were found 33 mammal species (28 natives and 5 exotics) grouped in the families Cricetidae (6 spp.), Didelphidae (3 spp.), Mephitidae (1 sp.), Mustelidae (2 spp.), Molossidae (3 spp.), Vespertilionidae (2 spp.), Canidae (2 spp.), Muridae (2 spp.), Felidae (1 sp.), Dasypodidae (1 sp.), Phyllostomidae (1 sp.), Hydrochoeridae (1 sp.), Octodontidae (1 sp.), Procyonidae (1 sp.), Caviidae (1 sp.), Chinchillidae (1 sp.), Myocastoridae (1 sp.), Leporidae (1 sp.) and Cervidae (1 sp.). Considering that the major part of Entre Ríos province has became crop and livestock fields, it is important to remark the role assumed by the environments of Perucho Verna stream, and likewise the hundred of small rivers that cross the province, in the preservation of mammal assemblages, since it is in these streams where still remain-though very poor-many of the original environments and mammal assemblages.

En este trabajo se listan los mamíferos del arroyo Perucho Verna, provincia de Entre Ríos, Argentina. El área de estudio está localizada en el centro-este de Entre Ríos; fitogeográficamente, la región está incluida en la Provincia Pampeana, con relictos empobrecidos de la colindante Provincia del Espinal e influenciada por la Provincia Paranaense a través de la selva en galería de los arroyos. Se llevaron a cabo ocho trabajos de campo (incluyendo trampeos, análisis de egagrópilas, transectas de observación, evidencias indirectas, entrevistas y colección de especies vegetales). Se detectaron siete asociaciones vegetales: campo de cultivo, pastizal, arbustal, monte xerófilo, selva en galería y selva mixta. En estas asociaciones se encontraron 33 especies de mamíferos (28 nativas y 5 exóticas) agrupadas en las familias Cricetidae (6 spp.), Didelphidae (3 spp.), Mephitidae (1 sp.), Mustelidae (2 spp.), Molossidae (3 spp.), Vespertilionidae (2 spp.), Canidae (2 spp.), Muridae (2 spp.), Felidae (1 sp.), Dasypodidae (1 sp.), Phyllostomidae (1 sp.), Hydrochoeridae (1 sp.), Octodontidae (1 sp.), Procyonidae (1 sp.), Caviidae (1 sp.), Chinchillidae (1 sp.), Myocastoridae (1 sp.), Leporidae (1 sp.) and Cervidae (1 sp.). Considerando que la mayor parte de la provincia de Entre Ríos se ha convertido en campos de cultivo y ganaderos, es importante remarcar el rol ocupado por los ambientes del arroyo Perucho Verna, como así también de los cientos de pequeños cauces que atraviesan la provincia, en la conservación de los ensambles de mamíferos, ya que es en estos arroyos donde aún se conservan -aunque pauperizados- muchos de los ambientes y ensambles de mamíferos originales.

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 (38º S) and the río Negro (41ºS) 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 AtlanticCoast) (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.