A late Pleistocene human footprint from the Pilauco archaeological site, northern Patagonia, Chile

Fossil footprints and what they mean for hominin paleobiology

Hominin footprints have not traditionally played prominent roles in paleoanthropological studies, aside from the famous 3.66 Ma footprints discovered at Laetoli, Tanzania in the late 1970s. This contrasts with the importance of trace fossils (ichnology) in the broader field of paleontology. Lack of attention to hominin footprints can probably be explained by perceptions that these are exceptionally rare and "curiosities" rather than sources of data that yield insights on par with skeletal fossils or artifacts. In recent years, however, discoveries of hominin footprints have surged in frequency, shining important new light on anatomy, locomotion, behaviors, and environments from a wide variety of times and places. Here, we discuss why these data are often overlooked and consider whether they are as "rare" as previously assumed. We review new ways footprint data are being used to address questions about hominin paleobiology, and we outline key opportunities for future research in hominin ichnology.

Experimental Development of Transport Percussion Marks on Obsidian Clasts, Pilauco Site, Chilean Northwestern Patagonia

In the Pilauco site (40°34′11″ S, 73°06′17″ W; 13,570 ± 70–12,540 ± 90 14C year BP), a previous geochemical trace analysis suggested that the Puyehue-Cordón Caulle Volcanic Complex is the most likely source for obsidian and dacitic glass artifacts at Pilauco. It was hypothesized that the glassy rocks were probably collected from a pebble beach deposit, as deduced by the presence of crescentic percussion marks on the artefact cortexes. An experimental study was designed using pebble obsidian clasts. Bidirectional transport produced by the waves on a beach was imitated by an oscillating table, using time lapses equivalent to a transport of 0.7 to 20 km. One hundred clasts were randomly selected and marked. The morphological changes were registered, measured and photographed after seven sequential runs. At the end of the experiment at 20 km, the mass loss of rounded and fractured clasts was 5% and 11%, respectively. Crescent, circular, pseudo-circular and irregular percussion marks occurred in both types of clasts. In all cases, the crescent marks developed a pseudo-frosted surface appearance, giving a whiter tone that masks the black color of the obsidian, exactly as observed in the cortex of the artifacts knapped in dacitic glass at the Pilauco site. Thus, it is highly probable that the vitreous material was obtained from a beach sourced by the Puyehue-Cordón Caulle Volcanic Complex.

Onthophagus pilauco sp. nov. (Coleoptera, Scarabaeidae): evidence of beetle extinction in the Pleistocene-Holocene transition in Chilean Northern Patagonia

The South American Pleistocene-Holocene transition has been characterized by drastic climatic and diversity changes. These rapid changes induced one of the largest and most recent extinctions in the megafauna at the continental scale. However, examples of the extinction of small animals (e.g., insects) are scarce, and the underlying causes of the extinction have been little studied. In this work, a new extinct dung beetle species is described from a late Pleistocene sequence (~15.2 k cal yr BP) at the paleoarcheological site Pilauco, Chilean Northern Patagonia. Based on morphological characters, this fossil is considered to belong to the genus Onthophagus Latreille, 1802 and named Onthophagus pilauco sp. nov. We carried out a comprehensive revision of related groups, and we analyzed the possible mechanism of diversification and extinction of this new species. We hypothesize that Onthophagus pilauco sp. nov. diversified as a member of the osculatii species-complex following migration processes related to the Great American Biotic Interchange (~3 Ma). The extinction of O. pilauco sp. nov. may be related to massive defaunation and climatic changes recorded in the Plesitocene-Holocene transition (12.8 k cal yr BP). This finding is the first record of this genus in Chile, and provides new evidence to support the collateral-extinction hypothesis related to the defaunation.

24.0 kyr cal BP stone artefact from Vale da Pedra Furada, Piauí, Brazil: Techno-functional analysis

Current archaeological paradigm proposes that the first peopling of the Americas does not exceed the Last Glacial Maximum period. In this context, the acceptance of the anthropogenic character of the earliest stone artefacts generally rests on the presence of projectile points considered no more as typocentric but as typognomonic, since it allows, by itself, to certify the human character of the other associated artefacts. In other words, without this presence, nothing is certain. Archaeological research at Piauí (Brazil) attests to a Pleistocene human presence between 41 and 14 cal kyr BP, without any record of lithic projectile points. Here, we report the discovery and interpretation of an unusual stone artefact in the Vale da Pedra Furada site, in a context dating back to 24 cal kyr BP. The knapping stigmata and macroscopic use-wear traces reveal a conception centred on the configuration of double bevels and the production in the same specimen of at least two successive artefacts with probably different functions. This piece unambiguously presents an anthropic character and reveals a technical novelty during the Pleistocene occupation of South America.