Aboriginal Australians represent one of the longest continuous cultural complexes known. Archaeological evidence indicates that Australia and New Guinea were initially settled approximately 50 thousand years ago (ka); however, little is known about the processes underlying the enormous linguistic and phenotypic diversity within Australia. Here we report 111 mitochondrial genomes (mitogenomes) from historical Aboriginal Australian hair samples, whose origins enable us to reconstruct Australian phylogeographic history before European settlement. Marked geographic patterns and deep splits across the major mitochondrial haplogroups imply that the settlement of Australia comprised a single, rapid migration along the east and west coasts that reached southern Australia by 49–45 ka. After continent-wide colonization, strong regional patterns developed and these have survived despite substantial climatic and cultural change during the late Pleistocene and Holocene epochs. Remarkably, we find evidence for the continuous presence of populations in discrete geographic areas dating back to around 50 ka, in agreement with the notable Aboriginal Australian cultural attachment to their country. Analysis of Aboriginal Australian mitochondrial genomes shows geographic patterns and deep splits across the major haplogroups that indicate a single, rapid migration along the coasts around 49–45 ka, followed by longstanding persistence in discrete geographic areas. Aboriginal Australians preserve one of the longest continuous cultural complexes known, with archaeological evidence dating initial settlement of the continent to around 50,000 years ago. Alan Cooper and colleagues have charted the subsequent progress of humanity in and around the continent in the form of 111 mitochondrial genomes from preserved hair samples. The results show that, from landfall in the north of Australia, people spread rapidly around the east and west coasts, meeting in southern Australia as early as 49,000 years ago. Strong regional patterns of mitochondrial DNA variation suggest that when people stopped moving they stayed put, putting down cultural roots that have weathered 50,000 years of significant cultural and climatic change.

Aboriginal mitogenomes reveal 50,000 years of regionalism in Australia

https://dialnet.unirioja.es/descarga/articulo/5173329.pdf

En la espiral de la energía

The end of the Pliocene marked the beginning of a period of great climatic variability and sea-level oscillations. Here, based on a new analysis of the fossil record, we identify a previously unrecognized extinction event among marine megafauna (mammals, seabirds, turtles and sharks) during this time, with extinction rates three times higher than in the rest of the Cenozoic, and with 36% of Pliocene genera failing to survive into the Pleistocene. To gauge the potential consequences of this event for ecosystem functioning, we evaluate its impacts on functional diversity, focusing on the 86% of the megafauna genera that are associated with coastal habitats. Seven (14%) coastal functional entities (unique trait combinations) disappeared, along with 17% of functional richness (volume of the functional space). The origination of new genera during the Pleistocene created new functional entities and contributed to a functional shift of 21%, but minimally compensated for the functional space lost. Reconstructions show that from the late Pliocene onwards, the global area of the neritic zone significantly diminished and exhibited amplified fluctuations. We hypothesize that the abrupt loss of productive coastal habitats, potentially acting alongside oceanographic alterations, was a key extinction driver. The importance of area loss is supported by model analyses showing that animals with high energy requirements (homeotherms) were more susceptible to extinction. The extinction event we uncover here demonstrates that marine megafauna were more vulnerable to global environmental changes in the recent geological past than previously thought. The Pliocene marine megafaunal extinctions caused functional diversity loss, which was not mitigated by newly evolved taxa in the Pleistocene. This paper points towards an abrupt loss of productive coastal habitats as a key extinction driver.

/pdf/the-pliocene-marine-megafauna-extinction-and-its-impact-on-2k4pbxwap7.pdf

The Pliocene marine megafauna extinction and its impact on functional diversity

Environmental histories that span the last full glacial cycle and are representative of regional
change in Australia are scarce, hampering assessment of environmental change preceding
and concurrent with human dispersal on the continent ca. 47,000 years ago. Here we present
a continuous 150,000-year record offshore south-western Australia and identify the timing of
two critical late Pleistocene events: wide-scale ecosystem change and regional megafaunal
population collapse. We establish that substantial changes in vegetation and fire regime
occurred B70,000 years ago under a climate much drier than today. We record high levels
of the dung fungus Sporormiella, a proxy for herbivore biomass, from 150,000 to 45,000
years ago, then a marked decline indicating megafaunal population collapse, from 45,000 to
43,100 years ago, placing the extinctions within 4,000 years of human dispersal across
Australia. These findings rule out climate change, and implicate humans, as the primary
extinction cause.

/pdf/humans-rather-than-climate-the-primary-cause-of-pleistocene-2gsl2u6wlk.pdf

Humans rather than climate the primary cause of Pleistocene megafaunal extinction in Australia.

Fil: Prevosti, Francisco Juan. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Evolution of South American Mammalian Predators During the Cenozoic: Paleobiogeographic and Paleoenvironmental Contingencies

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remain contentious, with major phases coinciding with both human arrival and climate change around the world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately, limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon data sets from the region. We identify a narrow megafaunal extinction phase 12,280 ± 110 years ago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediately prior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence and climate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts.

/pdf/synergistic-roles-of-climate-warming-and-human-occupation-in-5644rwheov.pdf

Teresa Civalero

Papers

Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation