Search

The maned wolf Chrysocyon brachyurus, the fourth largest canid, is categorized as Near Threatened on the IUCN Red List. The objectives of this study were to update information on the occurrence of this species in Argentina, compare the current distribution to that previously described for 1988–2008, and indicate the areas in which the species is exposed to particular hazards. We created a database that included 1,051 new records of C. brachyurus for 2009-2021, in addition to records for 1988–2008 that had not been reported previously. We calculated the area of occupancy of the species in Argentina to be 500,000 km2. Most of the new records of C. brachyurus are in the Chaco Seco, Espinal and Pampas ecoregions. Our findings indicate a current area of occupancy 61% higher than that calculated from records for 1988–2008. However the location and frequency of reported threats and the intense environmental transformation that characterizes the areas for which we obtained new records suggest counterintuitive implications for the conservation of the species because of increased human–wildlife interactions. Our study reveals the need for systematic research to improve the understanding of the ecological processes that affect the maned wolf in Argentina, and will aid in the development of conservation strategies for the species.

We report new data on the intersexual and geographical variation in body mass of the Geoffroy's cat (Oncifelis geoffroyi d'Orbigny and Gervais 1844), a little known small cat from South America, and combine them with the existing information to compare alternative hypotheses for variation in body mass. Most data on the body mass of O. geoffroyi have been obtained from previous research on this felid in four study areas of southern Brazil and central and southern Argentina. These data were added to those reported for other three additional locations. Our results set the body mass of O. geoffroyi to 4.26 ± 1.03 kg (mean ± SD, n = 56). We also show that males generally are heavier than females throughout most of this species' distributional range. Body mass dimorphism is 1.34 on average, but ranges from 1.19 and 1.21 in Uruguay and southern Chile, respectively, to 1.76 in the northern Pampas of Argentina. When data from the best sampled areas are considered (Torres del Paine, Lihué Calel, southern Pampas, Campos del Tuyú and southern Brazil), only male body mass varies with geographic location. More intriguingly, no correlation was found between body mass and latitude. Our results suggest a smaller mean weight of O. geoffroyi relative to what was previously published, but also suggest a wider variation. Our analysis do not support Bergmann's rule, according to which the largest individuals would occur in the southernmost regions of this cat's geographic distribution, while they seem supportive of a sexually-selected process affecting sexual size dimorphism in the Geoffroy's catSe reportan nuevos datos sobre la variación intersexual y geográfica de la masa corporal en el gato montés (Oncifelis geoffroyi d'Orbigny and Gervais 1844), un félido pequeño y poco conocido de América del Sur, y los combinamos con la información existente para evaluar dos hipótesis que explicarían esta variación. La mayor parte de los datos sobre masa corporal de O. geoffroyi fueron obtenidos en el marco de proyectos de investigación sobre este félido en cuatro áreas del sur de Brasil y centro y sur de Argentina. Estos datos se agregaron con registros para otras tres localidades. Nuestros resultados establecieron que la masa corporal promedio de O. geoffroyi fue de 4,26 kg (DE = 1,03 kg; n = 56). Demostramos además que los machos son más grandes que las hembras, y que este dimorfismo sexual ocurre en la mayoría de las localidades muestreadas a lo largo del rango de distribución de esta especie. El dimorfismo sexual en la masa corporal fue de 1,34 en promedio, pero varió entre 1,19 y 1,21 en Uruguay y Chile meridional, respectivamente, hasta 1,76 en la Pampa septentrional argentina. Al comparar los datos de las cinco localidades con mayor número de registros (Torres del Paine, Lihué Calel, Pampas meridionales, Campos del Tuyú y Brasil meridional) se encontró variación geográfica significativa solo en la masa corporal de los machos. No se registró una correlación positiva entre la masa corporal y la latitud. Estos resultados sugieren que el tamaño promedio de O. geoffroyi es menor que lo sugerido por registros anteriores, pero también sugieren que su variabilidad es mayor. Nuestro análisis no apoya la regla de Bergmann en cuanto a que los individuos más grandes se encontrarían en las regiones más meridionales de la distribución geográfica, mientras que sí apoyan un escenario de selección sexual para el dimorfismo sexual en el tamaño observado en este felino