Trace fossils on penguin bones from the Miocene of Chubut,southern Argentina

Several traces of biological interaction were found on penguin bones from the basal levels (Aquitanian) of the Miocene Gaiman Formation in the lower Chubut valley of the Provincia del Chubut, Argentina. The fossil-bearing beds were deposited in littoral to sublittoral environments within sediments of mostly pyroclastic origin. We interpret many traces to have been produced by predators and/or scavengers while the penguins were still in a breeding area. Many bones show cracking marks due to aerial exposure. The material is disarticulated as is usual in recent breeding areas. Potential predators were coeval terrestrial mammals, most probably marsupial carnivores. After a marine transgression, these bones were buried or exposed on the sea bottom where they could be colonized by algae, sponges, cnidarians, and other benthic organisms. We identified sponge borings in several bones. Other traces are interpreted to have been produced by echinoderms feeding on sponges or algae. No evidence of other invertebrate predators such as muricid or naticid gastropods, or decapods was found. Finally, other traces appear to have been generated by shark and possibly teleostean vertebrates feeding on epibionts. One coracoid is interpreted to have been marked by a shark that is common in the Gaiman Formation, the carcharhiniform Galeocerdo aduncus. From an ethological (Seilacherian) classification, traces on bones from the Gaiman Formation include Domichnia (sponge perforations), Praedichnia (terrestrial marsupials, sharks, teleosteans) and Pasichnia (echinoderms). Remarkably, remains of marine organisms with skeletons made of calcium carbonate are very poorly preserved in the Gaiman Formation. Only large oysters, sparse shell fragments, skeletal moulds, and bioturbation is evident. The fossil assemblage is mainly composed of phosphatic (e.g. teeth, bones, crustacean parts) and siliceous (sponge spicules, diatoms) remains.     

Fixing the territory,a turning point: The paradoxes of the Wichí maps of the Argentine Chaco

Indigenous mapping is a powerful political tool for long-marginalized populations to create visibility and establish land claims. In the case of Argentina, a country that was built on a denial of the presence of Indigenous peoples in the national territory, the emergence of these maps stemming from participatory processes coincided with the recognition of these communities' territorial rights in 1994. However, this mapping of Indigenous territories freezes extremely dynamic and complex socio-spatial realities just as it inflects their representations. In this paper, I reassess the weight and the role that Indigenous cartographic representations play in the evolution of these populations' spatial capital. Paradoxically, they give rise to more contradictions than they clarify. These paradoxes demonstrate the varied relationships different generations maintain with their territory, just as they concern its structure and its cartographic form. Therefore, based on the case of the Wichí of the Argentinian Chaco, this paper contributes to the understanding of contemporary issues of indigeneity by adopting a critical approach to Indigenous cartography. Whereas in Argentina cartographic knowledge is undergoing a process of decolonization, this does not apply to the legal system or to society as a whole.     

The youngest non-lepidosirenid lungfish of South America (Dipnoi,latest Paleocene–earliest Eocene,Argentina)

The first lungfish tooth plate from the Las Flores Formation, Chubut, southern Argentina, is described. This is the youngest ceratodontid known from the continent. In Africa, ceratodonts disappeared in the Eocene. Afterwards, they are only known from Australia until their extinction during the Pleistocene. The Las Flores tooth plate also represents the southernmost lungfish known since the Coniacian (early Late Cretaceous).     

An experimental approach to the study of interpersonal violence in Northeastern Patagonia (Argentina), during the late Holocene

This paper incorporates an experimental approach to the study of violence patterns in Northeastern Patagonia (Argentina) during the late Holocene. The underlying hypothesis considers a close association between socio-ecologic alterations during the Medieval Climatic Anomaly (MCA) (ca. 1150-600 years BP; Stine, 1994, 2000) and a probable increase in conflict levels. In order to test this hypothesis, human skulls (n = 986) were analyzed for bone lesions, discriminating late bone lesions, such as those produced by metal tools. The experimental approach used swine (Sus scrofa domestica) skulls, as proxies for human skulls, and incorporated original sabers. From this discriminating analysis, it can be inferred that no significant increase in violence signs were recorded until the first stages of Hispanic-indigenous contact (first half of 17th century). These findings emphasize the need for a revision of the implications of the dynamics of human populations in Northeastern Patagonia during the late Holocene.