Isotopic reconstruction of Proboscidean habitats and diets on enigmatic island of Sulawesi

Sulawesi is known for its complex geological and biogeographic history, which is reflected in their extinct and extant faunal assemblage. Evidence of oldest terrestrial fauna in Sulawesi was found in the Early Pleistocene sediment and evolved since then. Despite being mostly isolated from the mainland Southeast Asia; four successive Proboscidean taxa have been found from the southern part of the island. The four taxa are: Stegoloxodon celebensis, Stegodon sompoensis, Stegodon sp. B, and cf. Palaeoloxodon namadicus, in which respective taxa are included in successive faunal stages. The aim of this research is to reconstruct the diet and palaeoenvironment of these Proboscidean taxa by incorporating stable isotope analysis with the fossil faunal record, geology, and stratigraphy. Stable carbon (δ13C) and oxygen (δ18O) isotope analysis were especially used in this study. Our result suggests that Stegoloxodon celebensis and Stegodon sompoensis were flexible feeders and were able to adapt to different niches, from closed canopy forest to open vegetation, while the diets of Stegodon sp. B, Celebochoerus heekereni and cf. Palaeoloxodon namadicus suggest that they were more specialized.

Pleistocene sediment DNA reveals hominin and faunal turnovers at Denisova Cave

Denisova Cave in southern Siberia is the type locality of the Denisovans, an archaic hominin group who were related to Neanderthals1–4. The dozen hominin remains recovered from the deposits also include Neanderthals5,6 and the child of a Neanderthal and a Denisovan7, which suggests that Denisova Cave was a contact zone between these archaic hominins. However, uncertainties persist about the order in which these groups appeared at the site, the timing and environmental context of hominin occupation, and the association of particular hominin groups with archaeological assemblages5,8–11. Here we report the analysis of DNA from 728 sediment samples that were collected in a grid-like manner from layers dating to the Pleistocene epoch. We retrieved ancient faunal and hominin mitochondrial (mt)DNA from 685 and 175 samples, respectively. The earliest evidence for hominin mtDNA is of Denisovans, and is associated with early Middle Palaeolithic stone tools that were deposited approximately 250,000 to 170,000 years ago; Neanderthal mtDNA first appears towards the end of this period. We detect a turnover in the mtDNA of Denisovans that coincides with changes in the composition of faunal mtDNA, and evidence that Denisovans and Neanderthals occupied the site repeatedly—possibly until, or after, the onset of the Initial Upper Palaeolithic at least 45,000 years ago, when modern human mtDNA is first recorded in the sediments.

Pleistocene epilithic foraminifera from the Arctic Ocean

Attached epilithic foraminifera constitute an important but overlooked component of the benthic foraminiferal assemblage in the Pleistocene sediment of the central Arctic Ocean. We report 12 types of epilithic foraminifera that have colonised lithic and biogenic grains found in glacial sediments, including representatives of the genera Rhizammina, Hemisphaerammina, Ammopemphix, Diffusilina, Subreophax, Placopsilina, Placopsilinella, Hormosinelloides and Tholosina, accompanied by mat-like and ribbon-like forms of uncertain taxonomic affinity. The attached agglutinated forms appear to be colonisers, adapted to extremely oligotrophic conditions.