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The claims that children's hand and footprints on formerly soft travertine at Qiusang, Tibet, are about 200 ka old and are the earliest rock art on the planet are reviewed. The uranium-thorium results are inconsistent with a previous age estimate of another set of such prints nearby, which is itself at odds with finger-drawn Tibetan letters at that site. The claims also ignore the high susceptibility of open-site calcite travertine to surface retreat by weathering and the likely removal of uranium by rainwater. Similarly, deposition of detrital thorium can occur in such porous and weathered carbonates. Both processes are known to increase age estimates of reprecipitated carbonate deposits significantly. There is no evidence that hominins of the Middle Pleistocene occupied the central Tibetan Plateau during the penultimate glacial period. Several issues are considered, and recommendations are made for resolving the controversy. • The difficulties with applying uranium-thorium analysis to the dating of travertine are illuminated. • The most recent sensational claims based on this dating approach concern an open travertine site in Tibet. • It has been proposed that some hand and footprints are in the order of 200,000 years old. • The discovery of Tibetan writing characters suggests that the travertine markings can only be less than 1300 years old. • The significant discrepancy in this and previous studies is explained by leaching of uranium. [ABSTRACT FROM AUTHOR]

Acer (Sapindaceae) is an exceptional study system for understanding the evolutionary history, divergence, and assembly of broad-leaved deciduous forests at higher latitudes. Maples stand out due to their high diversity, disjunct distribution pattern across the northern continents, and rich fossil record dating back to the Paleocene. Using a genome-wide supermatrix combining plastomes and nuclear sequences (~585 kb) for 110 Acer taxa, we built a robust time-calibrated hypothesis investigating the evolution of maples, inferring ancestral ranges, reconstructing diversification rates over time, and exploring the impact of mass-extinction on lineage accumulation. Contrary to fossil evidence, our results indicate Acer first originated in the (north)eastern Palearctic region, which acted as a source for recurring outward migration. Warm conditions favored rapid Eocene-onward divergence, but ranges and diversity declined extensively as a result of the Plio-Pleistocene glacial cycles. These signals in genome-wide sequence data corroborate paleobotanical evidence for other major woody north-temperate groups, highlighting the significant (disparate) impact of climatic changes on the evolution, composition, and distribution of the vegetation in the northern hemisphere. • Genomics confirm paleobotanical data on origin and migration of north temperate flora. • American origin refuted in favor of northeastern Palearctic with outward migration. • Abundance of north-American fossils due to higher sampling and research intensity. • Warm conditions spur Eocene radiation – ranges, diversity decline with glacial cycles. • Climatic deterioration key to understanding north-temperate flora evolution, assembly. [ABSTRACT FROM AUTHOR]

The geologic and tectonic history of the Memnonia-Sirenum region of Mars has been reconstructed on the basis of geologic mapping and relative-age dating of rock units and structures using crater counts and superposition relations. Comparisons between the ages of rock unit formation and the orientations of the earliest structures associated with Tharsis demonstrate a strong interplay among tectonic, magmatic, and aqueous activity in the Memnonia-Sirenum region. Early Noachian geologic activity identified within this region includes the formation of large northeast-trending, extensional basins. Stratigraphic and tectonic evidence suggests that these basins formed concurrently with the early formation of Tharsis when the dynamo and associated magnetosphere were still in operation. In addition to the ancient basins, later Tharsis-influenced activity includes prominent tectonic fault systems associated with the formation of Tharsis and Arsia Mons. Detailed mapping of the faults indicates that structures associated with Memnonia and Sirenum Fossae resulted from the formation of Tharsis during the Middle to Late Noachian. Late-stage (Amazonian) activity also identified within this region includes valley networks and collapse depressions that are linked and/or occur among Tharsis-centered faults that cut features throughout this region, including Mangala Valles. • The Memnonia-Sirenum region contains some of the oldest stratigraphic units of the western hemisphere region of Mars. • The northeast trending basins and ranges identified appear to be the result of the initial Tharsis upwelling phase. • Continued upwelling resulted in the formation of the ridges and radial faults associated with the center of the uplift. • Basin development was influenced by changing hydrologic conditions linked to the formation of Tharsis. [ABSTRACT FROM AUTHOR]

Excavations in Hualongdong (HLD), East China, have yielded abundant hominin fossils dated to 300 ka. There is a nearly complete mandible that fits well with a partial cranium, and together they compose the skull labeled as HLD 6. Thus far, detailed morphological description and comparisons of the mandible have not been conducted. Here we present a comprehensive morphological, metric, and geometric morphometric assessment of this mandible and compare it with both adult and immature specimens of Pleistocene hominins and recent modern humans. Results indicate that the HLD 6 mandible exhibits a mosaic morphological pattern characterized by a robust corpus and relatively gracile symphysis and ramus. The moderately developed mental trigone and a clear anterior mandibular incurvation of the HLD 6 mandible are reminiscent of Late Pleistocene hominin and recent modern human morphology. However, the weak expression of all these features indicates that this mandible does not possess a true chin. Moreover, a suite of archaic features that resemble those of Middle Pleistocene hominins includes pronounced alveolar planum, superior transverse torus, thick corpus, a pronounced endocondyloid crest, and a well-developed medial pterygoid tubercle. The geometric morphometric analysis further confirms the mosaic pattern of the HLD 6 mandible. The combination of both archaic and modern human features identified in the HLD 6 mandible is unexpected, given its late Middle Pleistocene age and differs from approximately contemporaneous Homo members such as Xujiayao, Penghu, and Xiahe. This mosaic pattern has never been recorded in late Middle Pleistocene hominin fossil assemblages in East Asia. The HLD 6 mandible provides further support for the high morphological diversity during late Middle Pleistocene hominin evolution. With these findings, it is possible that modern human morphologies are present as early as 300 ka and earlier than the emergence of modern humans in East Asia. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Time-calibrated molecular phylogeny of Cetartiodactyla covering more than 90% of extant species. • The origin of Cetartiodactyla dates back to ∼67 Ma at the Cretaceous- Paleocene boundaries. • Relationship among major lineages and among families were recovered robustly. • Families divergence times are congruent with the available fossil records. • Missing-data has a limited effect on the estimation of the divergence times and in the support of the clades. Abstract Cetartiodactyla comprises one of the most diverse mammal radiations. Currently, 23 families, 131 genera and more than 330 species are recognized. Several studies have been trying to resolve its phylogenetic relationships. The most comprehensive dated phylogenetic hypothesis available includes only 55% of the extant species, precluding a clear understanding of ecological and evolutionary patterns in Cetartiodactyla. Here, we gathered all mitochondrial genetic data available in GenBank to build a robust Cetartiodactyla calibrated phylogenetic tree using 21 fossil calibration points. We found mitogenomic data for 225 species and included other 93 species from which there was at least one mitochondrial gene available. Using a Bayesian approach, we generated a dated tree comprising 90% of the extant Cetartiodactyla species (n = 318). The major lineages showed robust support and families divergence times are congruent with the available fossil evidence and with previously published phylogenetic hypotheses. By making available a dated phylogeny with extensively sampled clades, we expect to foster future studies on the origin, tempo and mode of Cetartiodactyla diversification. [ABSTRACT FROM AUTHOR]

Galveston Bay is the second largest estuary along the northern Gulf of Mexico coast, with a watershed containing one of largest concentrations of petroleum and chemical industries globally, as well as Houston, the fifth largest metropolitan area in the USA. Throughout the last century, extensive groundwater extraction to support these industries and an expanding population has resulted in significantly enhanced land subsidence (0.6–3.0 cm yr −1 ). The highest subsidence rates observed in the bay are within the lower 15 km of the San Jacinto River/Houston Ship Channel region (SJR/HSC), with distal areas in East and West Galveston Bays having subsidence rates on the order of 0.2 cm yr −1 . In order to investigate the impacts of subsidence on sedimentation, a series of 22 vibracores were collected throughout the bay, and 210 Pb and 137 Cs radioisotope geochronologies and grain size distributions were determined. Sediment accumulation rates are highest (1.9 ± 0.5 cm yr −1 ) in the SJR/HSC, and decrease (<0.6 cm yr −1 ) both seaward and towards low subsidence regions. These results indicate sedimentation rates are significantly (p < 0.01) higher in areas with elevated Relative Sea Level Rise (RSLR). However, throughout most of Galveston Bay sedimentation rates are lower (as much as 50%) than estimated RSLR, indicating a sediment accretionary deficit. In areas (e.g., Scott Bay) within the SJR/HSC, the bay has deepened by more than 1.5 m, suggesting that sediment accumulation cannot keep pace with RSLR. Ultimately, this has resulted in a loss of coastal wetlands and a conversion of marine habitats from relatively shallow to deeper water settings. [ABSTRACT FROM AUTHOR]

The Pongo fossil record of China extends from the Early Pleistocene to the Late Pleistocene, but to date, no late Middle Pleistocene samples of Pongo with precise absolute dating have been identified in southern China. Here, we report the recovery of 106 fossil teeth of Pongo from Ganxian Cave in the Bubing Basin, Guangxi, southern China. We dated the speleothems using Uranium-series and dated the two rhinoceros teeth using coupled electron spin resonance/Uranium-series dating methods to between 168.9 ± 2.4 ka and 362 ± 78 ka, respectively. These dates are consistent with the biostratigraphic and magnetostratigraphic age estimates. We further describe the fossil teeth from Ganxian Cave and compare them metrically to samples of fossil Pongo (i.e., Pongo weidenreichi , Pongo duboisi , Pongo palaeosumatrensis , Pongo javensis , and Pongo sp.) from the Early, Middle, and Late Pleistocene and to extant Pongo (i.e., Pongo pygmaeus and Pongo abelii) from Southeast Asia. Based on overall dental size, a high frequency of lingual cingulum remnants on the upper molars, and a low frequency of moderate to heavy wrinkling on the molars, we attribute the Ganxian fossils to P. weidenreichi. Compared with Pongo fossils from other mainland Southeast Asia sites, those from Ganxian confirm that dental size reduction of Pongo occurred principally during the Early and Middle Pleistocene. From the Middle to Late Pleistocene, all teeth except the P3 show little change in occlusal area, indicating that the size of these teeth remained relatively stable over time. The evolutionary trajectory of the Pongo dentition through time may be more complex than previously thought. More orangutan fossils with precise dating constraints are the keys to solving this issue. [ABSTRACT FROM AUTHOR]

The Abocador de Can Mata (ACM) composite stratigraphic sequence (els Hostalets de Pierola, Vallès-Penedès Basin, NE Iberian Peninsula) has yielded a diverse primate assemblage from the late Aragonian (Middle to Late Miocene). Detailed litho-, bio-, and magnetostratigraphic control has enabled an accurate dating of these fossil remains. Comparable data, however, were lacking for the nearby locality of Can Mata 1 (CM1), which yielded a dryopithecine canine of a female individual. Given the lack of hipparionin equids and giraffids, CM1 has been correlated to the latest Aragonian (Mammal Neogene [MN] zone MN7+8). Here we revise the age of CM1 based on fieldwork and associated paleomagnetic samplings undertaken in 2018–2021. Our results extend the ACM composite sequence upward and indicate that CM1 correlates to the earliest Vallesian (MN9). The updated ACM sequence has a thickness of ∼300 m and comprises 12 magnetozones correlated to subchrons C5Ar.1r to C5n.2n (∼12.6–11.1 Ma; latest MN6 to earliest MN9, late Aragonian to earliest Vallesian). CM1 is correlated to C5r.1r (11.146–11.056 Ma), with an interpolated age of 11.11 Ma, thus postdating the dispersal of hipparionin horses into the Vallès-Penedès Basin—which is correlated to the previous subchron C5r.1n, with an interpolated age of 11.18 Ma, and by definition marks the beginning of the Vallesian. CM1 also minimally postdates the earliest record of giraffids at ACM—representing their earliest well-dated occurrence in the basin—being correlated to C5r.1n with an interpolated age of 11.11 Ma. We conclude that CM1 has an earliest Vallesian (MN9) age of ∼11.1 Ma, intermediate between the Aragonian dryopithecins and the Vallesian hispanopithecins. Ongoing paleontological surveillance at ACM thus offers the prospect to yield additional earliest Vallesian ape remains, which are essential to clarify their taxonomic allocation as well as to confirm whether hispanopithecins evolved locally from dryopithecins rather than immigrating from elsewhere during MN9. [ABSTRACT FROM AUTHOR]

Dating the construction of dry-stone walls is challenging since such structures are typically built without any mortar that can be used for dating. Rock surface luminescence dating is a developing dating method that could advance chronological insights from structures constructed using dry-stone techniques. This study explores rock surface luminescence dating by targeting dry-stone walls from two enclosure complexes and a hut located in the pastoral upland landscape in Val di Sole, Italy. Gneissic rocks were collected from the dry-stone walls, including surfaces that were either exposed or covered (buried) during the time of sampling. Their respective exposure and burial histories were investigated by measuring the luminescence intensity in feldspar minerals from polymineral rock slices. From covered rock surfaces from one enclosure complex, we calculated recent burial ages (∽ 200 a) from one rock, and burial of ∽ 500 a (bottom surface) and 3750 ± 660 a (top surface) from a second rock. The top surfaces of two additional rocks date the construction of an adjacent hut to the Early Middle Ages. The luminescence-depth profile from one such rock has a complex exposure and burial history, including events that predate the hut's construction. Fitted exposure ages from a second enclosure complex suggest with significant errors either a recent age (<10 a) or construction during the 19th century AD. Burial dating using rock surface luminescence dating appears feasible for dry-stone walls provided that the rock surface was sufficiently exposed before being incorporated into the structure; here, the gneissic surfaces were bleached to depths of ∽ 0-2 mm before the last burial. Contrariwise, exposure dating generally underestimates the expected age. The variation in ages observed from our rock surfaces indicates that the degree of preservation of the wall, the position of the rock, erosion, and knowledge regarding the general archaeological setting are essential to interpreting the estimated ages. In this study, rock surface luminescence dating provides new, previously inaccessible chronological data with implications for interpreting human activities in the alpine areas of Val di Sole. [ABSTRACT FROM AUTHOR]

The rapid economic growth of the Republic of Korea (S. Korea) within the last half-century has resulted in a pronounced increase in anthropogenic Hg emission from coal combustion, oil refining, cement production, and waste incineration. The record of increasing atmospheric sources have been investigated with a historical reconstruction of Hg accumulation in 30 sediment cores collected from the Yeongsan Estuary. Within the last several decades, this region has undergone severe anthropogenic alteration, including the construction of an estuarine dam forming the Yeongsan Lake, and installation of numerous seawalls that eliminated vast tidal flats and restricted estuarine circulation. Total mercury concentrations (T-Hg) measured in sediments deposited after 1980 (23.2 ± 9.6 ng g −1 ; n = 273), were significantly higher than those reported for pre-industrial sediments (i.e. background values: 8.6 ± 2.7 ng g −1 ; n = 274). An extensive survey of surface samples show that T-Hg concentrations are highest above the dam, with a gradient to lower values further offshore. The concomitant timing of enrichment of T-Hg within the sedimentary record and increased National emissions in Korea suggests that regional sources dominate the input to the Yeongsan Estuary. This indicates that with sufficient regional historic emission data, T-Hg might be utilized as a geochronologic tool to aid in corroborating traditional radioisotopic methods. [ABSTRACT FROM AUTHOR]

In 2000, a complete fourth metatarsal (Mt4) of the ∼3- to 4-Million-year-old hominin Australopithecus afarensis was recovered in Hadar, Ethiopia. This metatarsal presented a mostly human-like morphology, suggesting that a rigid lateral foot may have evolved as early as ∼3.2 Ma. The lateral foot is integral in providing stability during the push off phase of gait and is key in understanding the transition to upright, striding bipedalism. Previous comparisons of this fossil were limited to Pan troglodytes , Gorilla gorilla, and modern humans. This study builds on previous studies by contextualizing the Mt4 morphology of A. afarensis (A.L. 333-160) within a diverse comparative sample of nonhuman hominoids (n = 144) and cercopithecids (n = 138) and incorporates other early hominins (n = 3) and fossil hominoids that precede the Pan - Homo split (n = 4) to better assess the polarity of changes in lateral foot morphology surrounding this divergence. We investigate seven morphological features argued to be functionally linked to human-like bipedalism. Our results show that some human-like characters used to assess midfoot and lateral foot stiffness in the hominin fossil record are present in our Miocene ape sample as well as in living cercopithecids. Furthermore, modern nonhuman hominoids can be generally distinguished from other species in most metrics. These results suggest that the possession of a rigid foot in hominins could represent a conserved trait, whereas the specialized pedal grasping mechanics of extant apes may be more derived, in which case some traits often used to infer bipedal locomotion in early hominins may, instead, reflect a lower reliance on pedal grasping. Another possibility is that early hominins reverted from modern ape Mt4 morphology into a more plesiomorphic condition when terrestrial bipedality became a dominant behavior. More fossils dating around the Pan - Homo divergence time are necessary to test these competing hypotheses. [ABSTRACT FROM AUTHOR]

Abstract: This paper critically reviews the various approaches used to estimate the age of the rock art in the Kimberley region of Western Australia. They include: (i) the relative superimposition of styles; (ii) the use of diagnostic subject matter (depictions of extinct animals, stone tool technology, introduced European and Asian objects and animals); (iii) the recovery of a ‘painted’ slab from a dated archaeological unit; (iv) radiocarbon dating of beeswax figures, charcoal pigments, organic matter in overlying mineral deposits and ‘accreted paint layers’ (oxalate rich crusts and amorphous silica skin), pollen grains from an overlaying mud-wasp nest; and (v) optically stimulated luminescence (OSL) dating of quartz grains from overlying mud-wasp nests. Future directions for rock art dating in the Kimberley include uranium-series dating of overlying and underlying mineral deposits. [Copyright &y& Elsevier]

Abstract: Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at two cave sites (El Harhoura 2 and El Mnasra) on the Atlantic coast of Morocco. We were able to calculate OSL ages for 32 of the 33 samples collected from the Middle Palaeolithic deposits, including the earliest and latest Aterian levels at both sites. These ages reveal periods of occupation between about 110 and 95 ka (thousands of years ago), and at ∼75 ka. A late Middle Palaeolithic occupation of El Harhoura 2 is also recorded at ∼55 ka. Our single-grain OSL chronologies largely support previous age estimates from El Mnasra and other sites along the Atlantic coast of Morocco, but are generally more precise, reproducible and stratigraphically more coherent (i.e., fewer age reversals). We compare the single-grain ages for El Harhoura 2 and El Mnasra with those obtained from single- and multi-grain OSL dating of Middle Palaeolithic deposits in the nearby sites of Contrebandiers and Dar es-Soltan 1 and 2, and with records of past regional environments preserved in sediment cores collected from off the coast of northwest Africa. A conspicuous feature of the new chronologies is the close correspondence between the three identified episodes of human occupation and periods of wetter climate and expanded grassland habitat. Owing to the precision of the single-grain OSL ages, we are able to discern gaps in occupation during Marine Isotope Stages 5 and 4, which may represent drier periods with reduced vegetation cover. We propose that these climatic conditions can be correlated with events in the North Atlantic Ocean that exert a major control on abrupt, millennial-scale fluctuations between wet and dry periods in northwest and central North Africa. [Copyright &y& Elsevier]

Abstract: Flake based assemblages (Mode 1) comprise the earliest stone technologies known, with well-dated Oldowan sites occurring in eastern Africa between ∼ 2.6-1.7 Ma, and in less securely dated contexts in central, southern and northern Africa. Our understanding of the spread and local development of this technology outside East Africa remains hampered by the lack of reliable numerical dating techniques applicable to non-volcanic deposits. This study applied the still relatively new technique of cosmogenic nuclide burial dating (10Be/26Al) to calculate burial ages for fluvial gravels containing Mode 1 artefacts in the Luangwa Valley, Zambia. The Manzi River, a tributary of the Luangwa River, has exposed a 4.7 m deep section of fluvial sands with discontinuous but stratified gravel layers bearing Mode 1, possibly Oldowan, artefacts in the basal layers. An unconformity divides the Manzi section, separating Mode 1 deposits from overlying gravels containing Mode 3 (Middle Stone Age) artefacts. No diagnostic Mode 2 (Acheulean) artefacts were found. Cosmogenic nuclide burial dating was attempted for the basal gravels as well as exposure ages for the upper Mode 3 gravels, but was unsuccessful. The complex depositional history of the site prevented the calculation of reliable age models. A relative chronology for the full Manzi sequence was constructed, however, from the magnetostratigraphy of the deposit (N>R>N sequence). Isothermal thermoluminescence (ITL) dating of the upper Mode 3 layers also provided consistent results (∼78 ka). A coarse but chronologically coherent sequence now exists for the Manzi section with the unconformity separating probable mid- or early Pleistocene deposits below from late Pleistocene deposits above. The results suggest Mode 1 technology in the Luangwa Valley may post-date the Oldowan in eastern and southern Africa. The dating programme has contributed to a clearer understanding of the geomorphological processes that have shaped the valley and structured its archaeological record. [Copyright &y& Elsevier]

Abstract: Most archaeologists using obsidian hydration dating (OHD) in the United States develop hydration rates from association of obsidian hydration rims with dates based on radiocarbon, subsequently using the rate for chronometric analysis. The overall accuracy of the process has never been quantified. This paper reports an accuracy analysis in which sources of uncertainty are defined and modeled and their effects quantified. A Monte Carlo simulation is used to quantify errors from rate development, while uncertainties in age resulting from chronometric analysis are calculated analytically. For typical ranges of error values, hydration rate errors of ∼5% or less are achievable in the absence of systematic errors, with errors of chronometric age estimates ∼20–30% or less. [ABSTRACT FROM AUTHOR]

Abstract: A set of 104 independently dated archaeomagnetic directions was used to extend the U.S. Southwest reference curve back to 375 cal BC and to calculate isolated mean VGPs centered on 960 cal BC and 2390 cal BC. Prior to this study, most U.S. Southwest reference curves extended to only ca. AD 585. This study employed Sternberg’s moving window technique with variably sized windows, rather than fixed windows, to smooth the dataset into a continuous curve. The size of each averaging window was determined by the density of data captured by the window, such that each window had a minimum data density of 5.0 and a minimum window size of 50 years. This approach differs from previous studies in the U.S. Southwest, which have applied a uniformly sized averaging window to a dataset regardless of the temporal distribution of the data. [ABSTRACT FROM AUTHOR]

Abstract: A well-corroborated morphological scheme of interrelationships for centipedes, once broadly accepted, has been in conflict with molecular data with respect to deep branching events. Expanded taxonomic coverage compared to previous analyses adds longer fragments for 28S rRNA and a structural alignment as part of a sample of four genes (two nuclear ribosomal and two mitochondrial) for 111 extant species; these sequence data are combined with morphology under parsimony and maximum likelihood, exploring both traditional multiple sequence alignment and direct optimization approaches. Novel automated procedures to incorporate secondary structure information are also explored. The molecular data in combination yield trees that are highly congruent with morphology as regards the monophyly of all centipede orders as well as the major groups within each of the large orders. Regardless of the optimality criterion or alignment strategy, the Tasmanian/New Zealand Craterostigmomorpha is resolved in a different position by the molecular data than by morphology. Addition of morphology overturns the placement of Craterostigmomorpha in favour of the traditional morphological resolution and eliminates the need to posit major character reversals with respect to developmental mode and maternal care. Calibration of the tree with Palaeozoic and Mesozoic fossils for a relaxed clock analysis corroborates the palaeontological signal that divergences between centipede orders date to the Silurian and earliest Devonian, and familial divergences are likewise almost wholly Palaeozoic. [Copyright &y& Elsevier]

Abstract: Terrestrial fossils that document the early colonization of land are scarce for >100 my after the Cambrian explosion. This raises the question whether life on land did not exist or just did not fossilize. With a molecular dating technique, we analyzed the origin of terrestrial chelicerate microarthropods (Acari, Oribatida) which have a fossil record since the Middle Devonian that is exceptional among soil animals. Our results suggest that oribatid mites originated in the Precambrian (571±37mya) and that the radiation of basal groups coincides with the gap in the terrestrial fossil record between the Cambrian explosion and the earliest fossilized records of continental ecosystems. Further, they suggest that the colonization of land started via the interstitial, ∼150 my earlier than the oldest fossils of terrestrial ecosystems. Overall, the results imply that omnivorous and detritivorous arthropods formed a major component in early terrestrial food webs, thereby facilitating the invasion of terrestrial habitats by later colonizers of higher trophic levels. [Copyright &y& Elsevier]

Abstract: Geological data from the Bura Hasuma region at Koobi Fora provide important constraints for estimating the ages of hominin fossils recovered there, including the cranium KNM-ER 1813. Strata of the upper Burgi, KBS, and Okote members in this part of Koobi Fora reflect three depositional regimes driven by changing paleogeography through time. The upper Burgi and lowermost KBS sequence in the southern Bura Hasuma region accumulated in a lacustrine to delta front setting, with highly localized depositional patterns, limiting the lateral extent of lithostratigraphic markers. Farther north, uppermost upper Burgi through KBS member strata document a fluctuating lake margin, with complex facies patterns. This interval is marked by laterally extensive lithostratigraphic markers, including molluscan packstones, beach sandstones, and stromatolite beds. The uppermost KBS and Okote members show a transition to dominantly fluvial character, with localized and discontinuous accumulation. An age model for the richly fossiliferous Area 123 sequence demonstrates the complexity of terrestrial accumulation patterns. Early lacustrine and delta front accumulation is marked by fairly continuous sedimentation, and high accumulation rates (up to ca. 91cm/k.yr.). The fluctuating lake margin interval reflects lower sedimentation rates coupled with intervals of exposure, decreasing accumulation significantly (to ca. 13cm/k.yr.). The capping fluvial interval is marked by significant erosion surfaces, breaks which may drop the overall accumulation rate even lower (ca. 0.3cm/k.yr.). The data provided here establish a geological framework at odds with a recent proposal of ages considerably younger (by ca. 250k.yr.) for many of the fossils from Area 123 and elsewhere. Tests of age models demonstrate that the younger ages are not possible. While minor refinements to age estimates for fossils are indicated by improved chronostratigraphic control, in the case of KNM-ER 1813, an age of younger than 1.78Ma is precluded on magnetostratigraphic grounds. [Copyright &y& Elsevier]

Abstract: The siphonous green algae are an assemblage of seaweeds that consist of a single giant cell. They comprise two sister orders, the Bryopsidales and Dasycladales. We infer the phylogenetic relationships among the siphonous green algae based on a five-locus data matrix and analyze temporal aspects of their diversification using relaxed molecular clock methods calibrated with the fossil record. The multi-locus approach resolves much of the previous phylogenetic uncertainty, but the radiation of families belonging to the core Halimedineae remains unresolved. In the Bryopsidales, three main clades were inferred, two of which correspond to previously described suborders (Bryopsidineae and Halimedineae) and a third lineage that contains only the limestone-boring genus Ostreobium. Relaxed molecular clock models indicate a Neoproterozoic origin of the siphonous green algae and a Paleozoic diversification of the orders into their families. The inferred node ages are used to resolve conflicting hypotheses about species ages in the tropical marine alga Halimeda. [Copyright &y& Elsevier]

Abstract: Sedimentary records of naturally occurring and fallout-derived radionuclides are widely used as tools for estimating both the ages of recent sediments and rates of sedimentation and bioturbation. Developing these records to the point of data interpretation requires careful sample collection, processing, analysis and data modeling. In this work, we document a number of potential pitfalls that can impact sediment core records and their interpretation. This paper is not intended as an exhaustive treatment of these potential problems. Rather, the emphasis is on potential problems that are not well documented in the literature, as follows: (1) the mere sampling of sediment cores at a resolution that is too coarse can result in an apparent diffusive mixing of the sedimentary record at rates comparable to diffusive bioturbation rates observed in many locations; (2) 210Pb profiles in slowly accumulating sediments can easily be misinterpreted to be driven by sedimentation, when in fact bioturbation is the dominant control. Multiple isotopes of different half lives and/or origin may help to distinguish between these two possible interpretations; (3) apparent mixing can occur due simply to numerical artifacts inherent in the finite difference approximations of the advection diffusion equation used to model sedimentation and bioturbation. Model users need to be aware of this potential problem. Solutions to each of these potential pitfalls are offered to ensure the best possible sediment age estimates and/or sedimentation and bioturbation rates can be obtained. [Copyright &y& Elsevier]

There is considerable interest in the possibility of using molecular phylogenies to estimate extinction rates. The present study aims at assessing the statistical performance of the birth–death model fitting approach to estimate speciation and extinction rates by comparison to the approach considering fossil data. A simulation-based approach was used. The diversification of a large number of lineages was simulated under a wide range of speciation and extinction rate values. The estimators obtained with fossils performed better than those without fossils. In the absence of fossils (e.g. with a molecular phylogeny), the speciation rate was correctly estimated in a wide range of situations; the bias of the corresponding estimator was close to zero for the largest trees. However, this estimator was substantially biased when the simulated extinction rate was high. On the other hand the estimator of extinction rate was biased in a wide range of situations. Surprisingly, this bias was lesser with medium-sized trees. Some recommendations for interpreting results from a diversification analysis are given. [Copyright &y& Elsevier]

Archaeological quartz artifacts and naturally fractured quartz fragments occur in a variety of cultural and geological contexts worldwide. For dating such objects we have developed the new Quartz Hydration Dating (QHD) technique. It relies on the phenomenon of water diffusion into quartz leading to the formation of a hydration layer that can be measured by a hydrogen profiling technique, and diffusivity data connecting the layer thickness with the hydration time. We have obtained such data by induced-hydration experiments in the temperature range 60 to 200 °C and derived a general equation for calculating diffusion coefficients which was validated by results from dated artifacts. The main factors influencing the diffusivity are temperature, the crystallographic orientation, measured as the angle between surface of hydration and crystal c-axis, and initial H content of the quartz. The experimental results are discussed in the frame of a diffusion-reaction model from the literature. The time range of QHD is 100 ya to over 100K ya. The error of age determination is 35%, but may be reduced to 20% by controlling for material variability. QHD is applicable to single-crystal specimens and aggregates of single crystals. Apart from its application to archaeology and geology, the technique is suited for detecting fakes. [Copyright &y& Elsevier]

An aeolian sand unit overlies the Middle Stone Age deposits at Blombos Cave on the southern Cape coast. These deposits contained culturally-important artefacts, including bone tools and pieces of engraved ochre, as well as a large number of worked lithics. The aeolian sand and two other remnants of the sand dune formed against the coastal cliff were dated using optical dating. To determine the dose received since deposition, measurements were made on 5 mg aliquots of purified quartz grains using the single-aliquot regenerative-dose (SAR) protocol. The results of several internal check procedures are reported and at least 15 replicate dose determinations are presented for each sample. Combining these dose values with measurements of the radioactive content of each sample resulted in an age of 69.2±3.9 ka for the unit within the cave, and a mean age of 70.1±1.9 ka for all three dune samples. This provides a minimum age for the Middle Stone Age material at Blombos Cave. [Copyright &y& Elsevier]

Snake Cave (Thailand) is an important site for the study of the evolution in Southeast Asia, leading to a discovery of rich and various faunas, including a human tooth. Fossils of large and small mammals converge to indicate, on the basis of faunal assemblage, a late Middle Pleistocene age for the fossiliferous layers; on the other hand, previous U-series dating of carbonates furnished a lower limit for the fossils of about 130 ky.In order to achieve a better comprehension of the chronology of the cave, the Uranium-series method for absolute age determination has been applied to some carbonates older than those studied previously and to fossils themselves.We used the isochron technique approach to yield valuable ages because spleleothem samples consist in a mixture of calcite and detrital contamination. The results obtained suggest that the main fossiliferous level is older than about 160 ky. The application of the U-series method to tooth samples from this tropical cave leads to erroneous ages, probably because of post depositional groundwater movements. [Copyright &y& Elsevier]

Fossiliferous deposits at Woranso-Mille span the period when Australopithecus anamensis gave rise to Australopithecus afarensis (3.8–3.6 Ma) and encompass the core of the A. afarensis range (ca. 3.5–3.2 Ma). Within the latter period, fossils described to date include the intriguing but taxonomically unattributed Burtele foot, dentognathic fossils attributed to Australopithecus deyiremeda , and one specimen securely attributed to A. afarensis (the Nefuraytu mandible). These fossils suggest that at least one additional hominin lineage lived alongside A. afarensis in the Afar Depression. Here we describe a collection of hominin fossils from a new locality in the Leado Dido'a area of Woranso-Mille (LDD-VP-1). The strata in this area are correlated to the same chron as those in the Burtele area (C2An.3n; 3.59–3.33 Ma), and similar in age to the Maka Sands and the Basal through lower Sidi Hakoma Members of the Hadar Formation. We attribute all but one of the LDD hominin specimens to A. afarensis , based on diagnostic morphology of the mandible, maxilla, canines, and premolars. The LDD specimens generally fall within the range of variation previously documented for A. afarensis but increase the frequency of some rare morphological variants. However, one isolated M 3 is extremely small, and its taxonomic affinity is currently unknown. The new observations support previous work on temporal trends in A. afarensis and demonstrate that the large range of variation accepted for this species is present even within a limited spatiotemporal range. The value added with this sample lies in its contribution to controlling for spatiotemporal differences among site samples in the A. afarensis hypodigm and its contemporaneity with non- A. afarensis specimens at Woranso-Mille. [ABSTRACT FROM AUTHOR]

This study demonstrates a novel approach to overcoming challenges associated with obtaining reliable radiocarbon dates for rock paintings. Using two independent methods, we obtained ages for Pecos River style paintings at Eagle Cave in Langtry, Texas. The first method employed plasma oxidation to isolate organic carbon directly from the paint layer for accelerator mass spectrometry C-14 measurement. The second method treated mineral accretion layers with phosphoric acid to isolate calcium oxalate for plasma oxidation cleaning, combustion, and C-14 measurement to obtain minimum and maximum ages for the paintings. Radiocarbon dates for the paintings are statistically indistinguishable, with a weighted average of 3280 ± 70 years BP calibrated to 1740-1420 cal BC (3690-3370 cal BP) at 2 sigma (95.4%) probability. Radiocarbon assays obtained for the overlying accretion layers are younger and underlying accretion layers are older. The chronological stratigraphy of the accretion and paint layers supports the validity of both dating methods. With accurate and reliable dating methods, rock paintings in the region can be studied alongside excavated cultural deposits to provide a more complete understanding of this hunter-gather society. These methods for dating rock paintings can be applied to many rock art provinces around the world. [ABSTRACT FROM AUTHOR]

• For the first time, Handeliodendron is resolved as the sister of Aesculus. • The American A. californica is sister to the Asian species within section Calothyrsus. • Asian origin of Aesculus in the Late Cretaceous with subsequent dispersals to America and Europe. • Co-evolution of ecological niches and morphological traits in some sections. In this study, we used RAD-seq data to resolve the phylogeny of the tribe Hippocastaneae (Sapindaceae) and conducted comparative analyses to gain insights into the evolution and biogeography of the group that had fossils dating back to the late Cretaceous. Hippocastaneae, including the horsechestnuts and buckeyes, is a well-supported clade in Sapindaceae that comprises 12–14 species in Aesculus , two in Billia , and one in Handeliodendron. Most species in the tribe are distributed in Eurasia and North America and exhibit a classic pattern of intercontinental disjunction in the Northern Hemisphere, while Billia occurs from southern Mexico to northern South America. The earliest fossils of Aesculus date back to at least the earliest Paleocene of eastern Asia and western North America, where there are also putative occurrences from the latest Cretaceous. The group provides an excellent system for understanding floristic disjunction in the Northern Hemisphere extending to the Neotropics. However, a strongly supported and well resolved phylogeny is presently lacking for the tribe. Previous phylogenetic studies using several gene regions revealed five well-supported clades in Aesculus , largely corresponding to five recognized taxonomic sections, but relationships among these clades and among Aesculus , Billia , and Handeliodendron were not well supported. In this study, we used RAD-seq data from 68 samples representing all clades and species of Hippocastaneae except Billia , for which we used one of two species, to further resolve relationships within the tribe. Our phylogenomic analyses showed strong support for a sister relationship between Aesculus and Handeliodendron , in contrast to previous findings which supported Billia as sister to Aesculus. Within Aesculus , relationships among sections were strongly supported as (sect. Calothyrsus , (sect. Aesculus , (sect. Macrothyrsus , (sect. Parryana , sect. Pavia)))). We found that the traditionally recognized section Calothyrsus was monophyletic, with all eastern Asian species sister to the western North American species, A. californica. Analyses of divergence times combined with biogeographic analyses suggested a Late Cretaceous origin of Hippocastaneae, in eastern Asia, western North America, and Central America (including southern Mexico), followed by isolation of Billia in Central America, extinction of the tribe ancestor in western North America, and divergence of Aesculus from Handeliodendron in eastern Asia. A Late Cretaceous origin of the common ancestor of Aesculus in eastern Asia was followed by dispersals into western North America, Europe, and eastern North America during the Late Cretaceous and the Paleogene. Our results support Aesculus as a relic of the boreotropical flora and subsequent intercontinental spread of the genus through the Bering and North Atlantic land bridges. We performed character mapping analyses, which revealed that biogeographic isolation and niche divergence may have played important roles in driving morphological evolution and lineage divergence in Aesculus. Our study demonstrates the value of RAD-seq data for reconstructing phylogeny back to the Late Cretaceous. [ABSTRACT FROM AUTHOR]

• Phylogenomic transcriptome analyses provides a robust phylogeny for the order Pseudoscorpiones. • Diversification of pseudoscorpions initiated somewhere between the Devonian and the Carboniferous. • Iocheirata (the venomous pseudoscorpions) is monophyletic and diversified mostly during the Mesozoic. • The lack of venom in Pseudoscorpiones is plesiomorphic, and not a synapomorphy of Epiocheirata. • Based on our results we proposed a new classification for Pseudoscorpiones. Pseudoscorpiones, with nearly 3700 described species, are an ancient and globally distributed group of arachnids with a fossil record dating back to the Middle Devonian. Previous attempts to reconstruct their phylogenetic history have used morphology or a few amplicons, mostly of rRNAs and mitochondrial genes, which have not been able to completely resolve family-level relationships nor the earliest nodes in the pseudoscorpion tree—those which are most informative about the origins of key characters like venoms and silk. Here we undertake a phylogenetic approach using 41 pseudoscorpion transcriptomes and a series of analyses that account for many of the common pitfalls faced in large phylogenomic analyses. All analyses, using concatenation methods and coalescent approaches, supported monophyly of Iocheirata (the venomous pseudoscorpions), which diversified mostly during the Mesozoic, but paraphyly of Epiocheirata, with a sister group relationship of Feaelloidea to Iocheirata, with Chthonioidea as their sister group. These three main lineages were established during the mid-to-late Paleozoic. Our phylogenetic scheme is consistent with the prior hypothesis that the lack of venom in Pseudoscorpiones is plesiomorphic and not a synapomorphy of Epiocheirata. Based on the results of this study, a new classification is proposed for Pseudoscorpiones including the following new nomenclatural and taxonomic acts: the new suborders Palaeosphyronida Harvey and Atoposphyronida Harvey for Dracochelidae and Feaelloidea, respectively; the newly recognized superfamily Garypinoidea for Garypinidae and Larcidae; the revised rank for Lechytiidae and Tridenchthoniidae, which are regarded as subfamilies of Chthoniidae; the revised rank for Tridenchthoniini and Verrucadithini which are regarded as tribes of Tridenchthoniinae; and the elevation of Hesperolpiinae as a distinct family, Hesperolpiidae. [ABSTRACT FROM AUTHOR]