Faunal Sequence Research Articles

The late Middle Pleistocene Zhongshan cave fauna from the Bubing Basin, southern China

The karstic caves in the Bubing Basin, Guangxi, southern China, contain abundant Quaternary mammalian fossils. These cave sites are located at varying altitudes that have been roughly correlated with chronological age (higher caves are older, lower caves are younger). A growing number of recent studies have established a regional biochronological sequence for these Bubing caves from the Early to the Late Pleistocene. Here, we describe a new mammalian assemblage from the Zhongshan Cave, that dates to the late Middle Pleistocene - Marine Isotope Stage 6 (191–130 ka). The age is supported by minimum ages derived from U-series dating of the deposits, and the ESR/U-series dating of one Rhinoceros tooth (∼184 ka). The Zhongshan mammalian assemblage, comprising 33 taxa of large-sized mammals, belongs to the Middle Pleistocene “Ailuropoda-Stegodon” faunal unit and, in this respect, most closely resembles the Ganxian fauna (362–168.9 ka). The high diversity and abundance of ruminant Artiodactyla (versus Perissodactyla) in the Zhongshan fauna suggest a diversity of forest to more open habitats in the Bubing Basin during this period.The Zhongshan fauna fills a gap in the biochronological framework of southern China, offering new insights into the evolutionary history of some mammalian lineages in the Bubing Basin. Overall, data indicate major changes in the Early to Late Pleistocene faunal sequence, particularly with more turnover during the Early-Middle Pleistocene transition compared to the Middle-Late Pleistocene transition.Comparison between faunas from the Bubing Basin with those from sites in the Chongzuo area, also in Guangxi, southern China, highlights two major phases in the general decline of large-sized mammals during the Middle to Late Pleistocene transitional period. In that respect, our results provide an updated biochronological background for further analyses of the region.

An integrative geochronological framework for the Pleistocene So'a basin (Flores, Indonesia), and its implications for faunal turnover and hominin arrival

Flores represents a unique insular environment with an extensive record of Pleistocene fossil remains and stone artefacts. In the So'a Basin of central Flores these include endemic Stegodon, Komodo dragons, giant tortoises, rats, birds and hominins, and lithic artefacts that can be traced back to at least one million years ago (1 Ma). This comprehensive review presents important new data regarding the dating and faunal sequence of the So'a Basin, including the site of Mata Menge where Homo floresiensis-like fossils dating to approximately 0.7 Ma were discovered in 2014. By chemical fingerprinting key silicic tephra originating from local and distal eruptive sources we have now established basin-wide tephrostratigraphic correlations, and, together with new numerical ages, present an update of the chronostratigraphy of the So'a Basin, with major implications for the faunal sequence. These results show that a giant tortoise and the diminutive proboscidean Stegodon sondaari last occurred at the site of Tangi Talo ∼1.3 Ma, and not 0.9 Ma as previously thought. We also present new data suggesting that the disappearance of giant tortoise and S. sondaari from the sedimentary record occurred before, and/or was coincident with, the earliest hominin arrival, as evidenced by the first records of lithic artefacts occurring directly below the 1 Ma Wolo Sege Tephra. Artefacts become common in the younger layers, associated with a distinct fauna characterized by the medium-sized Stegodon florensis and giant rat Hooijeromys nusatenggara. Furthermore, we describe a newly discovered terrace fill, which extends the faunal record of Stegodon in the So'a Basin to the Late Pleistocene. Our evidence also suggests that the paleoenvironment of the So'a Basin became drier around the time of the observed faunal transition and arrival of hominins on the island, which could be related to an astronomically-forced climate response at the onset of the Mid-Pleistocene Transition (MPT; ∼1.25 Ma) leading to increased aridity and monsoonal intensity.

Small game hunting in montane rainforests: Specialised capture and broad spectrum foraging in the Late Pleistocene to Holocene New Guinea Highlands

Moving into montane rainforests was a unique behavioural innovation developed by Pleistocene Homo sapiens as they expanded out of Africa and through Southeast Asia and Sahul for the first time. However, faunal sequences from these environments that shed light on past hunting practices are rare. In this paper we assess zooarchaeological evidence from Yuku and Kiowa, two sites that span that Pleistocene to Holocene boundary in the New Guinea Highlands. We present new AMS radiocarbon dates and a revision of the stratigraphic sequences for these sites, and examine millennial-scale changes to vertebrate faunal composition based on NISP, MNI, and linear morphometric data to shed light on variability in hunting practices, processes of natural cave deposition, and the local palaeoenvironment at the end of the LGM through to the Late Holocene. We show that Yuku was first occupied at least c. 17,500 years ago and that Late Pleistocene–Early Holocene hunters targeted a wide range of small-bodied and agile species from the mid-montane forest, with a particular focus on cuscus (Phalanger spp.). At Kiowa, occupied from around 12,000 years ago, a similar range of species were targeted, but with an added emphasis on specialised Dobsonia magna fruit bat hunting. We then integrate other zooarchaeological data from the wider Highlands zone to build a model of generalist-specialist hunting dynamics and examine how this more broadly contributes to our understanding of tropical foraging during the Late Pleistocene and Holocene.

A Villafranchian Hipparion-Bearing Mammal Fauna from Sésklo (E. Thessaly, Greece): Implications for the Question of Hipparion–Equus Sympatry in Europe

Recently collected fossil material in the Villafranchian locality of Sésklo, as well as a re-evaluation of a pre-existing, partly-published museum collection, allow the recognition of a lower faunal level in the locality, older than the main Equus-dominated fossil assemblage, dated in the Early Pleistocene (MNQ17). The lower level yielded, instead, an advanced hipparion, referred to the species Plesiohipparion cf. shanxiense, and a small number of associated taxa: an ostrich (Struthio cf. chersonensis), an unidentified proboscidean, the pig Sus arvernensis, two antelopes (Gazella cf. bouvrainae and Gazellospira torticornis), a large bovid (Bovini indet.), and a rhinoceros (Stephanorhinus sp.). The lower-level fauna is dated in the latest Pliocene (MN16) and indicates a rather open and dry palaeoenvironment. The faunal sequence in Sésklo shows that the hipparion did not co-occur with the stenonid horse, at least in this region. Previous reports on sympatry of these taxa may result from faunal mixing, requiring re-examination of the available samples.

Provisioning the Ritual Neolithic Site of Kfar HaHoresh, Israel at the Dawn of Animal Management

It is widely agreed that a pivotal shift from wild animal hunting to herd animal management, at least of goats, began in the southern Levant by the Middle Pre-Pottery Neolithic B period (10,000–9,500 cal. BP) when evidence of ritual activities flourished in the region. As our knowledge of this critical change grows, sites that represent different functions and multiple time periods are needed to refine the timing, pace and character of changing human-animal relationships within the geographically variable southern Levant. In particular, we investigate how a ritual site was provisioned with animals at the time when herd management first began in the region. We utilize fauna from the 2010–2012 excavations at the mortuary site of Kfar HaHoresh—the longest continuous Pre-Pottery Neolithic B faunal sequence in the south Levantine Mediterranean Hills (Early–Late periods, 10,600–8,700 cal. BP). We investigate the trade-off between wild and domestic progenitor taxa and classic demographic indicators of management to detect changes in hunted animal selection and control over herd animal movement and reproduction. We find that ungulate selection at Kfar HaHoresh differs from neighboring sites, although changes in dietary breadth, herd demographics and body-size data fit the regional pattern of emerging management. Notably, wild ungulates including aurochs and gazelle are preferentially selected to provision Kfar HaHoresh in the PPNB, despite evidence that goat management was underway in the Mediterranean Hills. The preference for wild animals at this important site likely reflects their symbolic significance in ritual and mortuary practice.

An innovative piston corer for large-volume sediment samples.

Coring is one of several standard procedures to extract sediments and their faunas from open marine, estuarine, and limnic environments. Achieving sufficiently deep penetration, obtaining large sediment volumes in single deployments, and avoiding sediment loss upon retrieval remain problematic. We developed a piston corer with a diameter of 16 cm that enables penetration down to 1.5 m in a broad range of soft bottom types, yields sufficient material for multiple analyses, and prevents sediment loss due to a specially designed hydraulic core catcher. A novel extrusion system enables very precise slicing and preserves the original sediment stratification by keeping the liners upright. The corer has moderate purchase costs and a robust and simple design that allows for a deployment from relatively small vessels as available at most marine science institutions. It can easily be operated by two to three researchers rather than by specially trained technicians. In the northern Adriatic Sea, the corer successfully extracted more than 50 cores from a range of fine mud to coarse sand, at water depths from three to 45 m. The initial evaluation of the cores demonstrated their usefulness for fauna sequences along with heavy metal, nutrient and pollutant analyses. Their length is particularly suited for historical ecological work requiring sedimentary and faunal sequences to reconstruct benthic communities over the last millennia.

Recent Foraminifera from the Chilka Lake, Orissa, East Coast of India

Chilka Lake is a brackish marine lagoon in the Orissa State, India. The Lake is divided into the Outer Channel, the Northern Sector, the Central Sector and the Southern Sector for the present study. A total of eighty eight species of foraminifera have been identified from the Chilka Lake. Asterorotalia inflata, A. Trispinosa, Cibicides lobatulus, Nonion grateloupi, Pararotalia nipponica, Ammobaculites exiguous, Miliammina fusca, M. fusca var., Quinqueloculina seminulum, Ammonia beccarii, A. Tepida, Elphidium craticulatum and Nonion deprssulus are abundant occurecne. Although the endemic species tolerate wide fluctuations in ecological variables, their reproduction is active under conditions of salinity from 30.0‰ to 40.0‰ and temperature from 27 0 to 32 0 C. Faunal sequences obtains from Outer Channel to the inner lake and from Northern Sector through Central Sector to Southern Sector, Miliammina fusca dominating in the Outer Channel and Quinqueloculina seminulum, the Central and Southern Sectors.

Mammal faunas in Europe at the end of the Early – Beginning of the Middle Pleistocene

Problems of mammal evolution in the Early and Middle Pleistocene are widely discussed in the literature. The stages of mammal evolution considered in their relation to other paleontological data, geological units and the paleomagnetic scale provide a solid basis for correlation of natural events within this time interval. The analysis of the data on the European mammal fauna makes it possible to compare the evolutionary stages of large and small mammal faunas and the evolutionary changes in indicator phyletic lineages between different regions and to find regional features of similarity or distinction. In this paper the authors made an attempt to analyze data on large and small mammal faunas in Eastern Europe within the interval from the Jaramillo paleomagnetic event to the beginning of the early Middle Pleistocene (1.07–∼0.7 Ma BP) and to compare them with analogous data from Western Europe. Main trends in evolution and distribution of large and small mammals (primarily Arvicolidae) during the studied time interval are revealed. The characteristics of the established principal stages in small mammal faunal sequences are given. The position of these stages with reference to the paleomagnetic and climatic-chronological scales are proposed.

Changes to the environment of intramontane basins in the light of malacological research of calcareous tufa: Podhale Basin (Carpathians, Southern Poland)

The profiles of calcareous tufa occurring in the Podhale Basin (Carpathians, Southern Poland) were subject to a detailed malacological analysis. Studies were carried out in 15 sites. Five of them represent the period of the Late Glacial and Holocene, and the remainder is tufa deposited during historical times. On the basis of malacological analysis, 10 faunistic assemblages were defined. Each developed under specific environmental and climatic conditions. The observed sequences of molluscan assemblages in vertical profiles were the basis for paleoenvironmental reconstruction, determining the main phases of climatic changes and the human impact on the natural environment. The faunal sequence observed indicates a cold climate and the predominance of open habitats in the Late Glacial, with progressing warming and the increasing significance of shaded habitats in the Early and Middle Holocene, as well as anthropogenic pressure in modern times. The results of malacological analysis were complemented with determination of the age of deposits by radiocarbon dating and the results of palynological analyses conducted in the sites of peatbogs occurring in Podhale. The reconstruction indicates similarities and differences in the paleogeographic development of mountain and upland areas of Central Europe.

Upper Givetian and Frasnian (Middle and Upper Devonian) conodonts from Ampriú (Aragonian Pyrenees, Spain): global correlations and palaeogeographic relations

Abstract: This report describes for the first time a part of the Middle and Upper Devonian conodont sequence of the Sierra Negra Subfacies in the Aragonian Pyrenees (Spain), establishing the basis for further sound correlations both across the distinct Pyrenean facies and subfacies and on other relevant world areas. The description of 20 conodont taxa and their stratigraphical distribution permits recognition of two separate time intervals. The older one corresponds to the lower Upper Givetian (Middle Devonian), hermanni to cristatus ectypus zones. The younger interval is uppermost Lower Frasnian to lower Middle Frasnian (Upper Devonian) and is equivalent to MN4–MN6 zones. The combination of litho‐ and conodont biofacies supports the distinction between the Sierra Negra and Renanué Subfacies. Conodont biofacies for the studied interval are partially close to the ones from the Compte Subfacies, but lithofacies are clearly different. This faunal similarity fosters accurate correlation between subfacies and stimulates further research aiming at Devonian Pyrenean basin(s) reconstruction. Additionally, this faunal sequence permits direct comparison with regions located in northern Gondwana and in the Russian platform for part of the interval. Comparison with Laurasia, mainly with the Northwest Territories of Canada and the north‐western United States, is also provided. Some taxa are also common with eastern and central Asia (China, Siberia, Tadzhikistan, Afghanistan), Australia and western USA (Nevada).

Aridity, faunal adaptations and Australian Late Pleistocene extinctions

The faunal extinctions of the Late Pleistocene saw the disappearance of a suite of giant marsupials, birds and reptiles from the Australian landscape. Attempts to explain these extinctions have invoked human activities and climate change as one or other of the primary drivers. Recently, the identification of some faunal species having adaptations to aridity has been forwarded as evidence that climate change could not have had a major role in the process. By default, humans must have been responsible. The notion of aridity and adaptations to aridity is examined in this paper with respect to the extant Red Kangaroo (Macropus rufus) and the extinct giant kangaroo Procoptodon goliah in particular. The few sites known that document intact Late Pleistocene faunal sequences are also considered in an attempt to unravel climatic versus human influences. A mounting body of evidence points to considerable climate change in the lead up to, during and after the period sometimes referred to as the ‘extinction window’ (between ∼50 and 40 ka). How many species were present at the time of human arrival remains unclear and there remains little evidence of a human-megafauna coexistence. The case for a primary human role in the extinction process is inferred rather than proven and further palaeoenvironmental studies are needed to clarify the role of climate change in this process.

Core-collapse supernovae and the Younger Dryas/terminal Rancholabrean extinctions

Early predictions that some supernovae release large quantities of prompt high energy photons are now corroborated by optical identification of core-collapse supernovae associated with extragalactic GRBS (beamed γ-ray bursts) and XRFS (beamed or un-beamed X-ray flashes). Given the in-galaxy supernova frequency and GRB and XRF recurrence statistics, significant Earth-incident events during the past several million years very likely occurred and nearby events should have affected the Earth and other planetary atmospheres, including terrestrial surface solar UV, the Earth’s climate, and its ecology. The Younger Dryas Stadial (∼12,900 to 11,550 calendar yr BP) began with sharply cooler temperatures in the Earth’s northern hemisphere, regional drought, paleoecological evidence compatible with increased UV, and abrupt increases in cosmogenic 14C and 10Be in ice and marine cores and tree rings. In North America, stratigraphic and faunal sequences indicate that a major pulse of mammalian extinctions (at least 23–31 genera) began very close to 12,830 calendar yr BP and was sudden: deposits one century younger are devoid of diverse extinct fauna remains. A 10 s beamed GRB within 2 kpc of the Earth delivers 100 kJ m −2 fluence to the Earth’s atmosphere, where it causes spallation and catalytic reactions depleting 35–50% O 3, and producing excess NO x species (which favor cooling, drought, and surface fertility), 14C, and 10Be. An un-beamed, 10 50 erg hard photon impulse at ∼250 pc produces similar terrestrial atmospheric effects. A well-characterized massive star supernova, the unusually close Vela event ( d = 250 ± 30 pc; total energy of 1–2 × 10 51 erg; age constrained from remnant nebula shock velocities considerations at 13,000–16,000 yr and from the pulsar characteristic age at ∼11,400 yr) may have initiated the Younger Dryas climate change, and caused the extinction of the terminal Rancholabrean fauna.

Cryptotephra from the 74 ka BP Toba super-eruption in the Billa Surgam caves, southern India

The ∼74 ka BP Youngest Toba Tuff (YTT), from the largest known Quaternary volcanic eruption, has been found for the first time as a non-visible ( crypto-) tephra layer within the Billa Surgam caves, southern India. The occurrence of the YTT layer in Charnel House Cave provides the first calendrical age estimate for this much debated Pleistocene faunal sequence and demonstrates the first successful application of cryptotephrochronology within a cave sequence. The YTT layer lies ∼50 cm below a major sedimentological change, which is related to global cooling around the MIS 5 to MIS 4 transition. Using this isochronous event layer the Billa Surgam Cave record can be directly correlated with other archaeological sites in peninsular India and palaeoenvironmental archives across southern Asia.

Dating megafaunal extinction on the Pleistocene Darling Downs, eastern Australia: the promise and pitfalls of dating as a test of extinction hypotheses

A key to understanding Late Pleistocene megafaunal extinction dynamics is knowledge of megafaunal ecological response(s) to long-term environmental perturbations. Strategically, that requires targeting fossil deposits that accumulated during glacial and interglacial intervals both before and after human arrival, with subsequent palaeoecological models underpinned by robust and reliable chronologies. Late Pleistocene vertebrate fossil localities from the Darling Downs, eastern Australia, provide stratigraphically-intact, abundant megafaunal sequences, which allows for testing of anthropogenic versus climate change megafauna extinction hypotheses. Each stratigraphic unit at site QML796, Kings Creek Catchment, was previously shown to have had similar sampling potential, and the basal units contain both small-sized taxa (e.g., land snails, frogs, bandicoots, rodents) and megafauna. Importantly, sequential faunal horizons show stepwise decrease in taxonomic diversity with the loss of some, but not all, megafauna in the geographically-small palaeocatchment. The purpose of this paper is to present the results of our intensive, multidisciplinary dating study of the deposits (>40 dates). Dating by means of accelerator mass spectrometry (AMS) 14C (targeting bone, freshwater molluscs, and charcoal) and thermal ionisation mass spectrometry U/Th (targeting teeth and freshwater molluscs) do not agree with each other and, in the case of AMS 14C dating, lack internal consistency. Scanning electron microscopy and rare earth element analyses demonstrate that the dated molluscs are diagenetically altered and contain aragonite cements that incorporated secondary young C, suggesting that such dates should be regarded as minimum ages. AMS 14C dated charcoals provide ages that occur out of stratigraphic order, and cluster in the upper chronological limits of the technique (∼40–48 ka). Again, we suggest that such results should be regarded as suspicious and only minimum ages. Subsequent OSL and U/Th (teeth) dating provide complimentary results and demonstrate that the faunal sequences actually span ∼120–83 ka, thus occurring beyond the AMS 14C dating window. Importantly, the dates suggest that the local decline in biological diversity was initiated ∼75,000 years before the colonisation of humans on the continent. Collectively, the data are most parsimoniously consistent with a pre-human climate change model for local habitat change and megafauna extinction, but not with a nearly simultaneous extinction of megafauna as required by the human-induced blitzkrieg extinction hypothesis. This study demonstrates the problems inherent in dating deposits that lie near the chronological limits of the radiocarbon dating technique, and highlights the need to cross-check previously-dated archaeological and megafauna deposits within the timeframe of earliest human colonisation and latest megafaunal survival.

Smithian (Early Triassic) ammonoids from Tulong, South Tibet

Intensive sampling of the Tulong Formation in South Tibet has facilitated the construction of a highly-resolved middle and late Smithian ammonoid succession. The new biostratigraphical sequence comprises the middle Smithian Brayardites compressus beds, Nammalites pilatoides beds, and the Nyalamites angustecostatus beds followed by the late Smithian Wasatchites distractus beds and Glyptophiceras sinuatum beds. This faunal succession correlates very well with that of other Tethyan sequences such as the Salt Range (Pakistan), Spiti (India), Oman and South China. The Smithian faunal sequence from Tulong contains several taxa with broad geographic distribution (e.g., Owenites, Paranannites spathi, Shigetaceras, Wasatchites), thus enabling correlation with faunal successions from areas outside the Tethys (e.g., USA, British Columbia, Arctic Canada, South Primorye, Siberia). Early Smithian ammonoid faunas are almost absent in Tulong because of a preservation bias (absence of carbonate rocks). Five new ammonoid genera ( Brayardites, Nammalites, Nyalamites, Shigetaceras, Tulongites) and six new species ( Brayardites crassus, Brayardites compressus, Prionites involutus, ? Subflemingites compressus, Tulongites xiaoqiaoi, Urdyceras tulongensis) are described.

Fishing up the Food Web?: 12,000 Years of Maritime Subsistence and Adaptive Adjustments on California's Channel Islands

Archaeologists working on California's northern Channel Islands have produced an essentially continuous record of Native American fishing and nearshore ecological changes spanning the last 12,000 years. To search for evidence of Pauly's “fishing down the foodweb” pattern typical of recent historical fisheries, we analyzed variation in the dietary importance of major marine faunal classes (shellfish, fish, marine mammals) on the islands through time. Faunal data suggest that the Island Chumash and their predecessors focused primarily on low-trophic-level shellfish during the Early and Middle Holocene, before shifting their economic focus to finfish and pinnipeds during the Late Holocene. Replicated in faunal sequences from the adjacent mainland, this trans-Holocene pattern suggests that Native Americans fished up the food web, a strategy that may have been more sustainable and had fewer ecological repercussions. Emerging technological data suggest, however, that some of the earliest Channel Islanders focused more heavily on higher-trophic-level animals, including marine mammals, seabirds, and waterfowl. These data emphasize the differences between the primarily subsistence-based foraging strategies of ancient Channel Islanders and the globalized market-based fisheries of modern and historic times, with important implications for understanding the long-term evolution and historical ecology of marine ecosystems.

The Liang Bua faunal remains: a 95 k.yr. sequence from Flores, East Indonesia

Excavations at Liang Bua, a limestone cave on the island of Flores, East Indonesia, have yielded a well-dated archaeological and faunal sequence spanning the last 95 k.yr., major climatic fluctuations, and two human species – H. floresiensis from 95 to 17 k.yr. 1 1 Recent excavations at Liang Bua indicate that the disappearance of Homo floresiensis and Stegodon from the sequence coincided with a volcanic eruption ∼17 ka ago - not ∼12 ka as previously interpreted. , and modern humans from 11 k.yr. to the present. The faunal assemblage comprises well-preserved mammal, bird, reptile and mollusc remains, including examples of island gigantism in small mammals and the dwarfing of large taxa. Together with evidence from Early-Middle Pleistocene sites in the Soa Basin, it confirms the long-term isolation, impoverishment, and phylogenetic continuity of the Flores faunal community. The accumulation of Stegodon and Komodo dragon remains at the site in the Pleistocene is attributed to Homo floresiensis, while predatory birds, including an extinct species of owl, were largely responsible for the accumulation of the small vertebrates. The disappearance from the sequence of the two large-bodied, endemic mammals, Stegodon florensis insularis and Homo floresiensis, was associated with a volcanic eruption at 17 ka and precedes the earliest evidence for modern humans, who initiated use of mollusc and shell working, and began to introduce a range of exotic animals to the island. Faunal introductions during the Holocene included the Sulawesi warty pig ( Sus celebensis) at about 7 ka, followed by the Eurasian pig ( Sus scrofa), Long-tailed macaque, Javanese porcupine, and Masked palm civet at about 4 ka, and cattle, deer, and horse - possibly by the Portuguese within historic times. The Holocene sequence at the site also documents local faunal extinctions - a result of accelerating human population growth, habitat loss, and over-exploitation.

Climate, people and faunal succession on Java, Indonesia: evidence from Song Gupuh

Song Gupuh, a partially collapsed cave in the Gunung Sewu Limestones of East Java, Indonesia, contains over 16 m of deposits with a faunal sequence spanning some 70 ka. Major changes in the range of animals represented show the impact of climate change and humans. The Terminal Pleistocene and Early Holocene was a period of maximum biodiversity. Human use of Song Gupuh and other cave sites in the region also intensified significantly from ca. 12 ka, together with a new focus on exploitation of small-bodied species (macaque monkeys and molluscs), the first evidence for import of resources from the coast, and use of bone and shell tools. Human activity, especially after the onset of the Neolithic around 2.6 ka, subsequently contributed to a progressive loss of many species from the area, including tapir, elephant, Malayan bear, rhino and tiger, and this extinction process is continuing. We conclude by discussing the biogeographical significance of Song Gupuh in the context of other sites in Java (e.g. Punung, Wajak) and further afield (e.g. Liang Bua).

Vertebrate paleontology, biostratigraphy, geochronology, and paleoenvironment of Qaidam Basin in northern Tibetan Plateau

Qaidam Basin is the largest terrestrial basin of the Tibetan Plateau and has the most continuous sedimentary record in the Cenozoic. Although constituting the first known fossil vertebrates of the Tibetan Plateau and discovered in early scientific expeditions in the 1930s, mammalian fossils from Qaidam Basin have not played a significant role in studying the basin stratigraphy. Our explorations in the Qaidam Basin during the past 8 years have resulted in the first well documented collection of fossil vertebrates from there. In addition to being the best organisms for terrestrial biostratigraphy in the Cenozoic, the new fossil vertebrates offer a unique window into the ancient biotas that chronicle the late Cenozoic uplift of the plateau and associated environmental changes. Here we establish for the first time a faunal sequence of early Oligocene to early Pliocene age. Four mammalian faunas are recognized: Olongbuluk Mammal Fauna (middle Miocene), Tuosu Mammal Fauna (early late Miocene), Shengou Mammal Fauna (early late Miocene), and Huaitoutala Mammal Fauna (early Pliocene). All four mammal faunas can be directly or indirectly tied to a paleomagnetic section in the Olongbuluk–Huaitoutala area, permitting robust calibration of the chronology of these faunas. At least four fish faunas are also found: Lulehe Fish Fauna (late early to early late Oligocene), Shengou Fish Fauna (early late Miocene), Eboliang Fish Fauna (late late Miocene to early Pliocene), and Yahu Fish Fauna (early Pliocene). The fish faunas represent the only records of their respective times in the Tibetan Plateau and thus by themselves cannot be used for age determination. However, these fish faunas are either integrated into paleomagnetic sections or directly tied to mammal faunas of known ages, permitting independent assessment of their chronology. Zoogeographically, Qaidam mammal faunas show increasing endemism through time, presumably related to topographic barriers formed by the growth and uplift of the Tibetan Plateau and to climatic changes triggered by the same tectonic process. Fishes that were trapped in internally drained basins developed pachyostotic morphologies caused by hypersaline environments, which are associated with the increasing aridity of the Tibetan Plateau since early Pliocene.

Large- and small-mammal distribution patterns and chronostratigraphic boundaries from the Late Pliocene to the Middle Pleistocene of the Italian peninsula

Over the last 50 years the studies on terrestrial mammals of the Italian peninsula have provided a large volume of data and a more detailed knowledge of faunal events during the Late Pliocene and Quaternary. Moreover geological, sedimentological, palynological and magnetostratigraphical investigations on the Pliocene–Pleistocene continental sedimentary basins have yielded the possibility of a detailed calibration of the faunal successions. Thus, palaeontologists have been able to reconstruct faunal sequences and to propose biochronological scales based on large and small mammals, respectively. In the present contribution an integration of the two biochronological scales is proposed, and the successions of bioevents are carefully compared. This integrated approach allows the constraint of the sequence of large- and small-mammal events in a more reliable way, and therefore it results in a more detailed and consistent chronological use of mammalian assemblages. Particular attention is paid to the faunal changes that correspond to the Middle–Late Pliocene (2.6 ma), Pliocene–Pleistocene (1.8 ma) and Early–Middle Pleistocene (Gauss–Matuyama transition) chronostratigraphical boundaries.