Luciano J. M. De Santis

Taphonomy and dispersion of bones scavenged by New World vultures and caracaras in Northwestern Patagonia: implications for the formation of archaeological sites

Scavenger birds can feed on large- to small-sized vertebrates and may contribute in the formation of archaeological sites. To evaluate the modifications and dispersal patterns of bones produced by New World vulture and caracara from Northwestern Patagonia, samples of adult sheep, young sheep, and hare carcasses were offered and subsequently analyzed. New World vultures and caracaras quickly fed on the samples. Taphonomic and bone dispersal patterns suggest two types of accumulations: (1) open-air sites with large and medium-sized vertebrates represented by complete, fractured, scratched, notched, and punctured elements and (2) rock shelter or cave sites dominated by small vertebrates represented by broken, corroded, fractured, and digested elements.

MICROMAMÍFEROS, TAFONOMÍA Y AMBIENTES DURANTE LOS ÚLTIMOS 3.800 AÑOS A.P. EN EL VALLE MEDIO DEL RÍO GRANDE, MENDOZA, ARGENTINA

Desde una perspectiva tafonomica y paleoambiental se estudiaron restos de micromamiferos recuperados de dos sitios arqueologicos que abarcan un periodo temporal desde 3.800 anos a.p. hasta el siglo XX y se ubican en el curso medio del rio Grande, sudoeste de la provincia de Mendoza (Cueva de Luna y Alero Puesto Carrasco). La presencia de marcas de digestion ligera y moderada indica que los micromamiferos fueron depositados por aves strigiformes, posiblemente Tyto alba. Esto contrasta con el modelo de intensificacion de los recursos planteado para los grupos cazadores-recolectores que habitaron el sur de Mendoza hacia el 2.000 a.p. Los conjuntos zooarqueologicos mostraron cierta estabilidad taxonomica, presentando especies patagonicas (p.ej. Lestodelphys halli, Reithrodon auritus y Euneomys chinchilloides) y otras afines al desierto del Monte (p.ej. Galea leucoblephara, Akodon iniscatus y Calomys musculinus), en contraste con las muestras actuales donde principalmente se hallaron especies patagonicas, senalando un paleoambiente mas arido y calido que el actual.

Small mammals (Didelphimorphia, Rodentia and Chiroptera) from Pampean Region, Argentina

We studied small mammal assemblages recovered from owl pellets collected at 11 locations throughout the Argentina’s Pampean Region. We identified 21 species, including two marsupials, one bat, and 18 rodents. From the analysis of this dataset, we could distinguish three main groups of small mammals that currently inhabit the Pampean Region: 1) a group of taxa related to Pampean agroecosystems ( Calomys spp., Akodon azarae , and Oligoryzomys flavescens ); 2) a group of Brazilian species ( Cavia aperea , Oxymycterus rufus , Necromys lasiurus , Necromys obscurus , Holochilus brasiliensis , and Monodelphis dimidiata ); and 3) a group including species from Patagonia, Espinal and Monte phytogeographic provinces ( Microcavia australis , Oligoryzomys longicaudatus , Eligmodontia typus , Graomys griseoflavus , and Akodon molinae ). In addition, we documented the first record of a species of the large-bodied group of Calomys in Buenos Aires province, expanding its distribution ca. 420 km southward.

Skull morphometrics of adult male Antartic fur seal, Arctocephalus gazella, and South American fur seal A. australis

The skull morphometrics of adult male Antarctic fur seal, Arctocephalus gazella (Peters, 1875) and South American fur seal, A. australis (Zimmermann, 1783) were investigated using a collection of 45 and 38 skulls, respectively. Eighteen measurements were taken for each specimen. Comparative univariate and multivariate statistical analyses included standard statistics, one-way analysis of variance, principal component analysis and discriminant analysis. Individual variation was relatively high for some variables, as expressed by the coefficient of variation. Skulls of A. gazella were larger than those of A. australis for all but two variables: squamosal jugal suture and rostral length. Both species differed significantly as shown by both univariate and multivariate analyses. The discriminant function correctly classified all specimens. The standardized canonical coefficients showed that the variables which most contribute to the differentiation between species were, in decreasing order, the rostral length, palatal length, palatal width at postcanine 5 and braincase width. The present study corroborates that A. gazella and A. australis are phenotipically distinct species.