Early Pleistocene Research Articles

Computer simulation of scavenging by hominins and giant hyenas in the late Early Pleistocene

Consumption of animal-sourced food is an important factor in broadening the diet of early hominins, promoting brain and body growth, and increasing behavioural complexity. However, whether early hominins obtained animal food by scavenging or hunting large mammals remains debated. Sabre-toothed felids have been proposed to facilitate the expansion of early Homo out of Africa into Europe 1.4–0.8 Ma by creating a niche for scavengers in Eurasia as the carcasses abandoned by these felids still contained abundant edible resources. In contrast, it has been argued that the niche for a large scavenger was already occupied in Eurasia by the giant hyena, preventing hominins from utilising this resource. This study shows that sabre-toothed felids generated carcasses rich in edible resources and that hominins were capable of competing with giant hyenas for this resource. The simulation experiments showed that maintaining an optimum group size is essential for the success of the hominin scavenging strategy. Early hominins could outcompete giant hyenas only if they could successfully dispute carcasses with them. Thus, in the presence of a strong competitor, passive scavenging is essentially the same as confrontational scavenging.

Mammalian diversity and age of the Salicas Formation (Late Miocene–Early Pleistocene), Northwestern Argentina: State of knowledge and new contributions

Late Cenozoic sediments in the Sierras Pampeanas of La Rioja and Catamarca provinces, Northwestern Argentina, have yielded fossil mammal remains from the Salicas Fm. Herein, we provide a taxonomic review of previously published material and new fossils from El Degolladito area, plus the San Blas area, and north of the Sierra de Mazán region (Villa Mervil, Villa Mazán, Santa Teresita, and Salar de Pipanaco localities). Zircon dating of volcaniclastic levels of the Salicas Fm localities reveals that the fossil vertebrates span from ca. 8.7 to 2.4 Ma (Late Miocene–Early Pleistocene), which in El Degolladito area (ca. 8.7–7.9 Ma) is more abundant and taxonomically rich and includes Metatheria (cf. Thylatheridum sp., Lycopsis sp.), Rodentia (Cardiomys sp., Prodolichotis prisca, Caviidae sp. A., Lagostomus pretrichodactyla, Metacaremys primitiva, Pseudoplataeomys elongatus, Tetrastylus sp.), Meridiungulata (Neobrachytherium sp., Hemihegetotherium torresi, Paedotherium minor, Protypotherium minutum, Typotheriopsis sp.), and Xenarthra (Eosclerocalyptus proximus, Stromaphorus compressidens, Nopachthus coagmentatus, Chasicotatus peiranoi, Paleuphractus argentinus, Proeuphractus limpidus, Prozaedyus sp., Vetelia gandhii, Pampatheriidae indet, Pilosa indet.). Lagostomus cf. L. pretrichodactyla, H. torresi, and Vetelia sp. have also been recovered in the outcrops near San Blas (without dating), whereas to the north of the Sierra de Mazán (ca. 5.7–2.4 Ma) only remains Dasypodidae, Glyptodontoinei, and N. coagmentatus have been found. Based on our analysis, it seems that the sampling conducted in El Degolladito area may have not yet fully uncovered the complete range of mammal diversity. The association from El Degolladito share affinity with those of the Late Neogene of Argentina previously referred to “Chasicoan” and “Huayquerian”, like Palo Pintado Fm, “Chasicoan” faunas of Cerro Azul Fm (e.g., Cerro La Bota locality), Loma de Las Tapias assemblages A and B, which is congruent with the absolute dating obtained.

The Neogene to Quaternary evolution of the Neuquén Andes broken foreland forced by tectonic, climatic and surface processes (southern Central Andes)

The Andes offer a distinctive example of the intricate interplay among climate, tectonics, and surface processes. This is exemplified by the mountain range's north-south orientation, which contrasts with the prevailing east-west wind direction. This interplay controls the uplift evolution of the broken foreland and thus the sediment transfer and erosion from mountain ranges to their forelands. The Neuquén Andes is a peculiar segment of the southern Central Andes, registering dramatic North-South variabilities in elevation, climate, and tectonic intensities established during the Neogene and Quaternary. In this study, we aimed to identify the tectono-stratigraphic evidence of the Neogene to Quaternary evolution of paleo-environments and drainage networks in the intramountainous basin of Pampa de Agua Amarga in the broken foreland of the southern Neuquén Andes of Argentina.Starting with a non-depositional and/or erosional phase during the Paleogene, the Pampa de Agua Amarga Basin underwent several phases of syn-orogenic sedimentation in the late Oligocene to early Miocene. The basin gradually shifted from a lacustrine to an alluvial depositional environment, with alluvial deposits becoming dominant in the mid-Miocene and fluvial deposits dominating in the Pliocene. A significant event occurred during the late Pliocene to early Pleistocene when coarse fluvial deposits were deposited, marking the last aggradation phase. In the early Pleistocene, the onset of incision triggered the drainage system to cut through the downstream topographic barrier. The excavation of the basin was abrupt, as evidenced by a mid-Pleistocene stepped fluvial terrace and alluvial fan that filled a large canyon across the southern end of the downstream topographic barrier.The study confirms the regional trend that Miocene basin infill is related to dry climate and high tectonic uplift, which overwhelmed the erosive power of the drainage network. The lowering of tectonic uplift intensity in the southern Neuquén Basin during the Plio-Pleistocene, along with sudden fluctuations in the global colder and wetter climate, ultimately led to the excavation of the intramountainous basin. The Westerlies Wind Belts generate high precipitation rates in the southern Neuquén Andean Cordillera, feeding the Negro River catchment in the retroarc Andean broken foreland. Consequently, the erosive power of the Negro River catchment overcame the declining tectonic uplift, causing significant erosion of the entire broken foreland and Cordillera of the southern Neuquén Andes. Conversely, more intense tectonic uplifts in the northern Neuquén Andes built a more effective orographic barriers that limited precipitation rates of both the Westerlies Wind Belt and South America Summer Monsoon, and preserved the intramountainous basins and mountain interior from erosion.

FINDINGS OF THE PRE-DNIPRO FOSSIL MOLLUSCAN FAUNA IN WESTERN UKRAINE

Over the past two decades, we have been studying a wide range of Quaternary sediments in western Ukraine in close cooperation with Ukrainian and Polish scientists. The sediments often contain paleofaunal remains such as bones of large and small mammals, mollusk shells and ostracods. During the period of research, we have discovered and studied more than 30 locations of molluscan fauna. Most of them date back to the Upper Pleistocene. Contrarily, there are few sites that would represent the fauna that inhabited the study area before the Dnipro glaciation. The same can be noted by analyzing the results of research by predecessors, in particular M. Kunytsia and I. Melnychuk, authors of the Geological Atlas of Galicia. We found molluscan fauna in six points. Two of the identified locations, namely Kalynivka and Liuboml, are located within the Volyn Polissia and are confined to the sediments between the Tiligulian moraine and Dnipro glacial and water-glacial deposits. Three more sections are located in Podillia. These include the Medzhybizh section (located on the left bank of the Southern Bug River to the west of the village of the same name), the Skala Podilska (discovered within the Burdiakivskyi special quarry on the northern outskirts of the Mezhyhirtsi (an outcrop on the left bank of the Dniester downstream near the confluence of the Hnyla Lypa River). The last one is found the Halych section, which reveals the structure of the ancient (fifth) Dniester terrace near the confluence of the Lukva River. The issue of detailed stratification and correlation of the studied sections remains challenging. This is due to the long-time influence of denudation factors such as glacial exhumation, slope processes, etc., as well as the different history of development of the territory under study. Molluscan fauna represents both warm (interglacial) and cold (glacial) conditions. The oldest fauna was found in the sediments of the Shyrokyne climatolith (Skala Podilska section) and represents warm interglacial conditions. It was also possible to identify fauna from loess formations, which indicates the dominance of cold arctic-boreal-alpine conditions in the accumulation of loess material in the early Pleistocene (MIS 20). Keywords: malacofauna; Pleistocene; climatolith; loess; alluvium.

Ovis gracilis sp. nov. (Artiodactyla, Bovidae) from the Lower Pleistocene of the Taurida Cave in the Crimea and History of the Genus Ovis

Ovis gracilis sp. nov. (Artiodactyla, Bovidae) from the Lower Pleistocene of the Taurida Cave in the Crimea and History of the Genus Ovis

Origin of endemic species in a moderately isolated ancient lake: The case of a snakehead in Inle Lake, Myanmar

AbstractInle Lake is an ancient lake in Myanmar, which is an important area with unique and diverse fauna. Its ichthyofauna is believed to have formed non‐radiatively, but the historical processes are poorly understood. To elucidate the mechanisms that shape species diversity in this moderately isolated biogeographical ‘island’, this study focused on a typical endemic fish of Inle Lake, Channa harcourtbutleri (Channidae, Anabantiformes), with its widely distributed sister species, C. limbata, and estimated the historical distribution and diversification processes of the endemic fish based on genome‐wide polymorphism (MIG‐seq) and mitochondrial DNA data. Channa harcourtbutleri contained two genetically and morphologically distinct groups inhabiting Inle Lake and the surrounding rivers respectively. These two groups were genetically the closest to each other; however, the riverine group showed some similarity to the closely related species, C. limbata from Southeast Asia. The mtDNA haplotypes of the endemic species were not monophyletic; most of the riverine group had haplotypes identical or close to those of C. limbata from the upper Irrawaddy and Salween rivers. The time tree suggested that C. harcourtbutleri diverged from C. limbata in the early Pleistocene and then experienced secondary contact with C. limbata in the late Pleistocene. Genetic and morphological differentiation within C. harcourtbutleri suggests that local adaptation to different environments has played an important role for the coexistence of its two forms with some reproductive isolation. Further, the results highlight the importance of multiple colonization and allopatric speciation in shaping biodiversity in the long‐term, moderately isolated environments.

Did Early Pleistocene hominins control hammer strike angles when making stone tools?

In the study of Early Pleistocene stone artifacts, researchers have made considerable progress in reconstructing the technical decisions of hominins by examining various aspects of lithic technology, such as reduction sequences, hammer selection, platform preparation, core management, and raw material selection. By comparison, our understanding of the ways in which Early Pleistocene hominins controlled the delivery and application of percussive force during flaking remains limited. In this study, we focus on a key aspect of force delivery in stone knapping, namely the hammerstone striking angle (or the angle of blow), which has been shown to play a significant role in determining the knapping outcome. Using a dataset consists of 12 Early Pleistocene flake assemblages dated from 1.95 Ma to 1.4 Ma, we examined temporal patterns of the hammer striking angle by quantifying the bulb angle, a property of the flake's Hertzian cone that reflects the hammer striking angle used in flake production. We further included a Middle Paleolithic flake assemblage as a point of comparison from a later time period. In the Early Pleistocene dataset, we observed an increased association between the bulb angle and other flake variables related to flake size over time, a pattern similarly found in the Middle Paleolithic assemblage. These findings suggest that, towards the Oldowan–Acheulean transition, hominins began to systematically adjust the hammer striking angle in accordance with platform variables to detach flakes of different sizes more effectively, implying the development of a more comprehensive understanding of the role of the angle of blow in flake formation by ∼1.5 Ma.

The geoheritage of Olduvai Gorge, Tanzania: providing geological answers to human origin questions

Abstract While Olduvai Gorge, Tanzania, is most famous for its impressive and formative record of early human technology, Pleistocene fauna and hominin fossils, its geological record is equally important. At Olduvai, palaeoanthropologically significant sites are often preserved in primary context (not redeposited), and they can be contextualized within the palaeoenvironments in which the hominins lived. This has provided an exceptional opportunity to assess not only hominin evolutionary changes over time, but also to understand their adaptive behaviour including toolmaking, foraging and sociality. Abundant volcanic material from the nearby Ngorongoro Volcanic Highlands, interspersed within and between archaeology-bearing deposits, made Olduvai a target for some of the earliest applications of radiometric dating using the K/Ar system. Ultimately, the 40 Ar/ 39 Ar dating system has produced ages with exceptional precision. Early radiometric dating at Olduvai helped establish the antiquity of the hominin lineage, and early palaeomagnetic studies (and the ‘Olduvai event,’ the longest normal subchron within the reversed Matuyama Chron) were critical in establishing the importance of Olduvai in the field of geochronology. More recently, high-resolution palaeoclimate studies of the palaeolake that once occupied the Olduvai Basin have helped to reconstruct the palaeoenvironments encountered by hominin species. Over a century of geological research has secured Olduvai's status as an important site for geoheritage.

Low‐Latitude Forcing and High‐Latitude Response of the South Asian Summer Monsoon Through the Pliocene

AbstractPrecipitation carried by the Asian summer monsoon influences the livelihoods of millions of people, and there has been a great deal of work trying to reveal the driving mechanisms behind past changes. Compared to the widely studied East Asian summer monsoon, the behavior of the South Asian summer monsoon (SASM) in the Pliocene is still not well known. Here, we present new high‐resolution geochemical (Rb/Sr and Ti) data from the lacustrine Yuanmou Basin (Southwest China) spanning the Pliocene to early Pleistocene (4.30–2.0 Ma) that permit detailed analysis of hydroclimate changes related to orbital‐scale SASM variability. We find a clear weakening of the SASM at 2.9–2.75 Ma, which may be related to warming in the high‐latitude southern hemisphere and a weakening of atmospheric circulation at low latitudes over the Indian Ocean. Our results highlight that 405‐ and 100‐Kyr eccentricity forcing had a dominant role in driving climate change in the Yuanmou Basin during the Pliocene to early Pleistocene. Based on analysis of our data from the Yuanmou Basin, coupled with marine data from the Arabian Sea, we suggest that orbital‐scale SASM variability during the Pliocene was mainly controlled by changes in low‐latitude insolation. In addition, oscillations of the West Antarctic ice sheet after ∼3.5 Ma also significantly influenced the evolution of the SASM on orbital time scales.

Evolution of the North Anatolian Fault from a diffuse to a localized shear zone in the North Aegean Sea during the Plio-Pleistocene

SUMMARY The North Anatolian Fault is the ∼1200-km-long active continental transform boundary between Anatolia and Eurasia. This strike-slip system initiated around 10–12 Ma and experienced diachronous episodes of strain localization along its strike. The structural evolution of the ∼350-km-long fault segments crossing the North Aegean Sea remains to be accurately investigated. There, the modern North Anatolian Fault is localized along two main branches: the northern branch ends at the North Aegean Trough and the southern branch ends at the Edremit-Skyros Trough. The Evia Basin is located in the North Aegean Domain between the North Anatolian Fault and the Corinth Rift. This study presents seismic reflection lines crossing the aforementioned structures of the North Aegean Domain, which document their subsurface structure and the sedimentary record of their activity since the Messinian. The seismic-reflection data set is tied to regional-scale stratigraphic markers, which constrains the age of main tectonic events related to the formation of the North Anatolian Fault. The seismic-reflection lines show that the two main branches of the North Anatolian Fault became localized structures at 1.3–2 Ma, coevally with the formation of the Evia Basin. Since 2 Ma, the North Aegean Troughs developed as a series of horsetail basins propagating westwards at the termination of the branches of the North Anatolian Fault. On a regional scale, the wide and diffuse North Anatolian transtensive shear zone active from Serravalian to Late Pliocene turned into a narrower shear zone at the two main branches of the North Anatolian Fault since the Early Pleistocene. This abrupt episode of strain localization occurred in the frame of the major Early Pleistocene change in stress regime from NE–SW to N–S extension, which has been observed throughout the Aegean Sea.

Oligocene to Pleistocene mudwhelks (Gastropoda: Potamididae, Batillariidae) of the Eurasian Paratethys Sea – Diversity, origins and mangroves

Potamidids (Potamididae, Batillariidae) are today typical inhabitants of coastal mudflats in tropical and warm temperate seas. From the Oligocene to the Early Pleistocene, the Eurasian Paratethys Sea harbored a striking diversity of mudwhelks as well. Based on occurrences from 466 localities covering an area of about 3 million km2 we trace range expansions of potamidids from the Western Tethys and the Proto-Mediterranean Sea into the Eurasian Paratethys Sea, coinciding with global warming trends, such as the Miocene Climate Optimum, the Tortonian Thermal Maximum and the Mid-Pliocene Warm Period. For several species and genera, the stratigraphically oldest occurrences are documented from Rupelian localities south of the Paratethys, which indicates a northward migration over time. A hypothetical refuge along western Africa is hypothesized to explain the 9 Myr long gap between Oligocene and Sarmatian occurrences of Potamides in Europe. Highest potamidid diversities in the Central Paratethys coincided with the Miocene Climate Optimum. The second diversity peak is observed during the Sarmatian when the Volhynian flooding united the Central and Eastern Paratethys in a “Mega-Paratethys”. This event appears to have boosted potamidid diversity at least in the western part of the Paratethyan basin. About 25% of the species belong to Paratethyan lineages, which partly passed the Badenian/Sarmatian Extinction Event.A close relation with mangrove environments is documented for Mesohalina, Ptychopotamides and Terebralia and is assumed for Tiarapirenella. The retreat of mangroves from the Paratethys following the Miocene Climate Optimum is reflected by the loss of large species. Latest Middle Miocene to Late Miocene (Sarmatian) potamidid faunas were dominated by species of Tiaracerithium and Potamides, which were adapted to mudflats devoid of mangroves. Maeotian and Akchagylian potamidid faunas were low diverse, comparatively small and indicate two last phases of immigrations from the Mediterranean region. An influx from the Arctic region during the “Akchagylian marine incursion” can be excluded as explanation for the exotic occurrence of Akchagylian potamidids.

With Impressions Chosen from Another Time: Core Technologies and Debitage Production at the Lower Palaeolithic Site of Notarchirico (670–695 ka; layers F to I2)

The earliest evidence of bifaces in western Europe is dated to the initial phase of the Middle Pleistocene (la Noira, Notarchirico, Moulin Quignon, 700–670 ka), with the findings of Barranc de la Boella (1.0–0.9 Ma) considered to be an earlier local evolution. No transition assemblages are recorded during this time frame, and the “abrupt” appearance of bifaces during this time frame is associated with significant cognitive shifts in human technological behaviours (Acheulean techno-complex). The new investigations conducted at the site of Notarchirico unearthed 30 ka of repeated human occupation (695–670 ka, layers F-I2) during MIS 17, with evidence of bifacial tools in layer G (680 ka) and F along with other heavy-duty implements (LCTs, pebble tools, etc.). Massive production of debitage products realised on local raw materials collected in situ through simple and efficient core technologies characterises a large part of the lithic assemblage with a high ratio of diversified light-duty tools, including modified chert nodules. Despite core and flake assemblages being a recurrent trait of Lower Pleistocene contexts, the increase in retouched implements recorded at the onset of the Middle Pleistocene has been considered a significant technological shift. The technological analysis of the debitage products presented in this work highlights recurrent and systematic technological behaviours of the hominins of Notarchirico—who proved to efficiently overcome the raw materials dimensional constraints—even in the layers without bifaces. This may shed light on the meaning of cultural and behavioural innovation that the Acheulean techno-complex is thought to bring over Europe. It is plausible that given the substantial homogeneity of the lithic strategies within the sequence of Notarchirico, which only the “introduction” of the bifaces in the upper layers seems to interrupt, a supposed behavioural or cultural change in the site might have already occurred in the lowermost portion of the sequence. In this work, we evaluate the degree of change—if any—from a technological perspective by analysing the debitage reduction sequences.

Pleistocene Lang Trang fauna in North Vietnam: taxonomic composition and habitats

New data on the taxonomic composition and ecological characteristics of Late Pleistocene vertebrates and invertebrates from the Lang Trang cave in northern Vietnam are presented. Based on the materials collected in progress of the work of the Joint Vietnam - Russia Tropical Science and Technology Research Center in 2020-2022, various representatives of the Stegodon-Ailuropoda Fauna of the second half of the Middle - early Late Pleistocene of Southeast Asia were identified, including primates Gigantopithecus blacki, Pongo sp., Trachypithecus sp., Presbytis sp., Macaca nemestrina, M. cf. fascicularis, M. cf. mulatta, and Macaca sp., carnivorans Panthera tigris, Neofelis nebulosa, and Arctonyx collaris rostratus, a lipotyphlan Chodsigoa hoffmanni, a bat Ia io, rodents Hystrix kiangsenensis, Leopoldamys neilli, and Rattus rattus, proboscideans Stegodon sp. and Elephas maximus, perissodactyls Tapirus indicus, Dicerorhinus sumatrensis, Rhinoceros sondaicus, and Rh. unicornis, artiodactyls Sus scrofa, S. barbatus, Tragulus kanchil, Hydropotes inermis, Muntiacus muntjak, Axis porcinus, Rusa unicolor, Capricornis sumatraensis, Bubalus arnee, and Bos sp., a crocodile Crocodylus sp., a turtle Cuora sp. and an abundant gastropod association, presented by six terrestrial forms, two freshwater species and a coastal-marine species Ellobium aurismidae. Gigantopithecus blacki, Macaca cf. fascicularis, M. cf. mulatta, Neofelis nebulosa, Chodsigoa hoffmanni, Ia io, Leopoldamys neilli, Rattus rattus, Rhinoceros unicornis, Sus barbatus, Tragulus kanchil, Hydropotes inermis, Axis porcinus, crocodiles, turtles, and most of gastropod species were identified for the first time in the Lang Trang Fauna based on these studies. Of particular interest is the finding of the giant ape G. blacki, one of the latest in the fossil record. The habitats of the fauna are characterized as mosaic biotopes with a predominance of wet stations and the participation of mangrove swamps and coastal lowlands; these conditions could have existed in the area of the cave during a major marine transgression of the early Late Pleistocene.

The knapping strategies in the Paleolithic on the Yunnan-Guizhou Plateau, southwest China: A regional particularity

The Paleolithic industry in southern China has long been considered as “cobble-tool tradition” or “chopper-chopping tool”, or even “Mode 1” in the international community since the 1940s (Movius, 1948). However, these denominations are biased since local facts are much more diversified not only because of the discovery of the bifacial phenomenon in Bose (Guangxi, southern China), but also the presence of a debitage (core-flaking) tradition on the Yunnan-Guizhou Plateau of southwestern China. This study will present the general lithic traditions in the southwestern Chinese provinces of Guizhou and Yunnan, where existed a long-lasting debitage culture and small flake-tool industry in the lithic assemblages dating to the Early Pleistocene until the Early Holocene. These lithic traditions are still not well recognized among researchers, and this situation could hinder the discussion of other archaeological phenomena in this region, such as the emergence of the Hoabinhian in Yunnan Province. The debitage tradition in southwestern China may represent regional adaptations and technological stability of the populations in a subtropical mountainous and forest environment. In this context, the appearance of large shaped tools and other knapping strategies and bone industry in the final Late Pleistocene (after 50–40 ka BP) on the Yunnan-Guizhou Plateau seems to be a “sudden event” and may indicate local innovations or the arrival of new populations, and contribute to the cultural diversification in the region.

Characterization of the West Siberian lineage of zokors (Mammalia, Rodentia, Spalacidae, Myospalacinae) and divergence in molar development

AbstractZokors (Myospalacinae) continue to be the center of systematics discussions. Phylogenetic schemes based on molecular data do not always agree with each other, nor can phylogenetic schemes based on paleontological material be complete due to the only-partial description of West Siberian zokors. This paper tries to fill this gap and presents a description of the West Siberian lineage from the late early Pleistocene to the present, together with an analysis of molar development in other zokor lineages. We describe two new species and one subspecies (Myospalax myospalax krukoveri n. ssp., Myospalax convexus n. sp., Prosiphneus razdoleanensis n. sp.) ancestral to the extant Myospalax myospalax Laxmann, 1769. We also reveal differences in the ontogeny of molars of modern species that were not previously detailed. These differences, together with paleontological data, indicate that in the West Siberian lineage, peramorphosis occurred in the structure of the chewing surface (with the exception of the lower m1), whereas in all other zokor lineages, there was pedomorphosis. On the basis of these results, we suggest a new view on the systematics of Myospalacinae.UUID: http://zoobank.org/b06d6c99-1648-454b-9b95-4d869bfe8bdc

<i>Ovis gracilis</i> sp. nov. (Artiodactyla, Bovidae) in the Lower Pleistocene of the Taurida Cave in the Crimea and the History of the Genus <i>Ovis</i>

А new species Ovis gracilis sp. nov. is described based on the study of fossil remains of Bovidae from the Lower Pleistocene of the Taurida Cave, the Crimea. This not very large sheep had the horn cores with homonymous torsion and short sinuses, and slender metapodia. The remains of Ovis from Taurida are among the oldest in Europe and the first evidence of the presence of Ovis in the Еarly Pleistocene of the Crimea. The species O. gracilis was a part of the fauna of the Taurida Cave, dated within 1.8–1.5 Ma. The appearance of this species in the south of Eastern Europe could be associated with one of the early waves of dispersal from Asia, along the Alpine-Himalayan belt just prior to the Olduvai paleomagnetic episode.

Mesoscale Shoreline Evolution on a Carbonate Sand Island: Anegada, British Virgin Islands

Anegada, the easternmost island of the Virgin Islands group (Caribbean Sea), is a low Pleistocene carbonate platform surrounded by Horseshoe Reef, the world’s third-largest fringing reef. The western part of the island consists of an extensive beachridge plain (>40 ridges). The sandy carbonate shoreline exists in three morphodynamic domains that exhibit distinctive behaviour over the 59-year study period (1953 to 2012). The northern shore is dominated by westerly longshore drift under fair-weather conditions and cross-shore sediment transport during high-energy events. Storm wave run-up and high nearshore sediment availability contribute to the construction of shore-parallel beachridges. The western end of the island is affected by refracted waves that drive strong erosion and sediment transport. This is reflected in a succession of alternating rapid shoreline recession and progradation phases over the study period. The south–central shoreline is exposed to low wave energy and is stable and colonised by mangroves. The fringing reef plays a dominant role in mesoscale shoreline morphodynamics, both as a sediment source and in wave energy dissipation. Quasi-stable points and embayments suggest a strong influence of the reef framework in controlling the shoreline’s morphology and position. Sediment transfer from the reef to the shoreline appears to take place via shore-oblique, linear sediment transport pathways that develop across the lagoon in response to the modification of incoming waves. Cannibalisation of the shoreline sediment over the past 50 years is leading to straightening of the shoreline planform. This is counter to the long-term (Holocene) development of beachridges and suggests a change from a strongly positive to negative sediment budget.

Seasonality and lake water temperature inferred from the geochemistry and sclerochronology of quaternary freshwater bivalves from the Turkana Basin, Ethiopia and Kenya

Reconstructing past environmental variability at short (annual-decadal) time scales is critical for understanding ecosystem change and ecological drivers of evolution. One promising approach to reconstructing that variability is through the use of stable isotope geochemistry and sclerochronology, the study of growth banding in organisms that undergo accretionary growth. We used a combination of sclerochronology, conventional stable isotope ratios and clumped isotope paleotemperatures to improve our understanding of past seasonality and climate variability in the Turkana Basin (Kenya, Ethiopia), which experiences a highly seasonal (tropical semi-desert) climate. In this case study, we apply these approaches to both Early Pleistocene and Holocene bivalve shells (Etheria and Pseudobovaria) to develop a model using various proxies of seasonal-interannual temporal variability in lake temperature and isotope chemistry. We leverage this model to better understand how lakes in the Turkana Basin have changed over short time-scales in the past. One modern (1979) river oyster has exclusively negative δ18O values through ∼1.5 yrs of growth and clumped isotope temperature reconstructions (30.1–31.5 °C) consistent with a river delta provenance. Late Holocene shells show a wider range of isotopic variability within each shell's growth history than the modern sample (∼2‰ for the modern sample vs. 5–7‰ for the Late Holocene samples) and near modern paleotemperatures, suggesting growth under both seasonal Omo flood pulse and lacustrine conditions. Middle Holocene shells exhibit less δ18O variability, consistent with growth in fresher Lake Turkana water at the end of the African Humid Period (12-5 ka), and with both surface water temperatures and water column temperature range similar to the Late Holocene. The Early Pleistocene shells have large seasonal δ18O cycles (4–7‰), with δ18O values comparable to modern and Holocene deltaic shells, and a large range of paleotemperatures (21.8–31.3 °C, including temperatures notably cooler than those measured in the modern lake: 25–31 °C), reflecting growth under significant seasonality in paleo-Omo River runoff. Oxygen isotope cycles suggest high degrees of seasonality of the paleo-Omo River runoff (or that of other major influents) into paleolake Lorenyang at ∼1.6 Ma, which may be similar to modern hydroclimate conditions. Comparison to prior datasets from nearby outcrops in the same basin suggests an increase in hydroclimate seasonality between 1.9 and 1.6 Ma. The combination of clumped isotope paleotemperature estimates from shallow water species such as E. elliptica with TEX86 measurements (derived here from previously published, contemporaneous sediment core studies from the south basin of Lake Turkana), which record temperatures near the oxycline, may provide a new approach to estimating past temperature variability along a vertical profile in lakes, thereby providing information on water column mixing regimes. Our approach greatly expands our toolkit for understanding coupled climate seasonality and variability in the Turkana Basin.

Glacial–Interglacial Cycles and Early Human Evolution in China

China is a crucial region for investigating the relationship between climate change and hominin evolution across diverse terrestrial ecosystems. With the continuous development of palaeoclimatology, chronology, and archaeology, the environmental and hominin record of the Early and Middle Pleistocene in China is steadily accumulating, shedding light on the effects of climate change on the distribution of early human settlements and population dynamics. However, the migration and dispersal of these early humans within long-term climate fluctuations and their underlying mechanisms remain to be clarified. Based on the spatial-temporal distribution of 95 Early to Middle Pleistocene archaeological sites in China, we found that intensified hominin activities gradually shifted southward under the influence of multiple glacial–interglacial cycles. The frequent bidirectional movements of these early humans between north and south were assumed as follows. During glacial periods, hominins living in North China migrated to southern areas, while inter-glacial periods witnessed the northward expansion of hominins inhabiting South China. Among all the potential driving mechanisms, we suggest that the available resources in terrestrial ecosystems may be the most fundamental factor. Combined with paleoenvironmental and archaeological records, we provide an Asian perspective for a better understanding of how the glacial–interglacial cycles shaped early human evolution.

Evolutionary dynamics of Euphorbia carniolica suggest a complex Plio-Pleistocene history of understorey species of deciduous forest in southeastern Europe.

Deciduous forests form the dominant natural vegetation of Europe today, but were restricted to small refugia during Pleistocene cold stages, implying an evolutionary past shaped by recurrent range contractions and expansions. Cold-stage forest refugia were probably widespread in southern and central Europe, with the northwestern Balkan Peninsula being of particular importance. However, the actual number and location of deciduous forest refugia, as well as the connections between them, remain disputed. Here, we address the evolutionary dynamics of the deciduous forest understorey species Euphorbia carniolica as a proxy for past forest dynamics. To do so, we obtained genomic and morphometric data from populations representing the species' entire range, investigated phylogenetic position and intraspecific genetic variation, tested explicit demographic scenarios and applied species distribution models. Our data support two disjoint groups linked to separate refugia on the northwestern and central Balkan Peninsula. We find that genetic differentiation between groups started in the early Pleistocene via vicariance, suggesting a larger distribution in the past. Both refugia acted as sources for founder events to the southeastern Alps and the Carpathians; the latter were likely colonised before the last cold stage. In line with traditional views on the pre-Pleistocene origin of many southeastern European deciduous forest species, the origin of E. carniolica was dated to the late Pliocene. The fact that E. carniolica evolved at a time when a period of continuous forestation was ending in much of Eurasia provides an interesting biogeographical perspective on the past links between Eurasian deciduous forests and their biota.