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Oxyarietites boletzkyi n.gen., n.sp., nouveau genre et nouvelle espèce d’ammonite dans le Sinémurien inférieur de Bourgogne (France) : un rare précurseur des morphologies oxycônes pour le Jurassique.
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L’une des toutes premières ammonites à coquille presque oxycône observée dans les séries fossilifères après la crise faunique de la limite Trias/Jurassique est décrite. Elle provient du Sinémurien inférieur (chronozone à Semicostatum ou à Turneri) de Bourgogne (Mavilly-Mandelot, Côte-d’Or, France). Cette nouvelle forme, Oxyarietites boletzkyi n. gen., n. sp., possède une coquille involute, comprimée et carénée dont le type clairement suboxycône est nouveau pour le Sinémurien inférieur. En raison de son aire ventrale carénée, ce taxon se rattache probablement à la super-famille des Arietitoidea Hyatt, 1875 sensu Guex (1995) mais son attribution familiale est incertaine et son origine évolutive reste énigmatique. Outre son intérêt taxonomique, cette découverte est importante car elle pose le problème de la valeur adaptative des caractères liés à la géométrie des coquilles d’ammonites. Il est actuellement admis que les coquilles involutes, comprimées et carénées de type suboxycône et oxycône favorisent significativement l’hydrodynamisme et donc la mobilité des espèces qui les possèdent. Il est surprenant que l’acquisition de ce probable avantage adaptatif n’ait pas favorisé l’implantation au sein des peuplements du nouveau taxon, qui reste une forme rare. Dans tous les cas, la découverte d’O. boletzkyi n. gen., n. sp. rajeunit d’environ 2 millions d’années la mise en place des morphologies oxycônes au cours de la phase de reconstitution de la biodiversité post-crise Trias/Jurassique. Oxyarietites boletzkyi n.gen., n. sp., a new genus and species of ammonite for the Lower Sinemurian of Burgundy (France): a rare forerunner of the oxycone morphologies for the Jurassic. One of the very first quasi-oxycone ammonites following the Triassic/Jurassic boundary crisis is described. It was collected from the fossiliferous Lower Sinemurian (Semicostatum or Turneri Chronozone) strata of Burgundy (Mavilly-Mandelot, Côte-d’Or, France). The new taxon, Oxyarietites boletzkyi n. gen., n.sp., possesses an involute, compressed and keeled shell of suboxycone morphology, a shell type previously unknown for the Lower Sinemurian. The discovery makes younger by about 2 Ma the emergence of keeled (sub)oxycone shells following the Triassic/Jurassic boundary crisis. Its obviously keeled ventral area allows a probable assignation to the Arietitoidea Hyatt, 1875 sensu Guex (1995) superfamily, but family level assignation and its evolutionary origin remain obscure. Although, it is generally accepted that involute, compressed and keeled suboxycone and oxycone ammonite shells possess the best hydrodynamical abilities and mobility, the acquisition of this probable adaptive advantage in O. boletzkyi n. gen., n. sp. does not go together with abundancy in the fossil record.
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Oxychilus (Drouetia) viridescens (Gastropoda: Pulmonata: Oxychilidae), a new species from Santa Maria, Açores, and a review of the subgenus
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Oxygen and strontium isotopes as provenance indicators of fish at archaeological sites: the case study of Sagalassos, SW Turkey
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In this paper, we investigate the potential use of oxygen and strontium isotope ratios (d18Op and 87Sr/86Sr) measured in archaeological fish enamel as provenance indicators. d18Op and 87Sr/86Sr were measured in a suite of archaeological carp remains recovered from the Anatolian townsite of Sagalassos dated to the Early Byzantine period (AD 450e650) and compared to that of modern fish, river and lake waters from the Anatolian region. We used sequential leaches in weak acetic acid to remove diagenetic Sr from fossil tooth enamel, monitoring the effectiveness of this approach by measuring the Sr/Ca ratios of the leachates via an isotope dilution thermal ionization mass spectrometry method (ID-TIMS). d18Op values mostly excluded a riverine origin. 87Sr/86Sr ratios of one fish overlapped with the 87Sr/86Sr signatures of two lakes in the Anatolian region, and at least one lake (Gölcük) could be removed as a candidate owing to a very distinctive 87Sr/86Sr signature not found in any of the fish remains. Most of the tooth samples analyzed could not be assigned a precise geographical origin since the 87Sr/86Sr ratios measured in enamel did not match that of any of the local lakes selected as potential origin. This result suggests that carp may have originated from lakes that have not yet been sampled, although this conclusion is not supported by other archaeological evidence. Alternatively, the lack of correspondence between lakes and fish Sr isotope ratios highlights several possible sources of uncertainties including spatial heterogeneity in 87Sr/86Sr ratio within a lake, the contribution of dietary strontium to the 87Sr/86Sr ratio of fish tooth enamel, and post-mortem alteration of the tooth Sr isotope signal during fossilization. In spite of the high precision of the strontium isotope analyses and the wide range of variation in the surface waters of the Anatolian lakes and rivers, this method may remain limited to distinguishing between lakes situated in regions of bedrock of very distinct age and geology until these sources of uncertainty are more fully investigated.
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Oxygen concentration profiles in soft sediments of Lake Baikal (Russia) near the Selenga Delta
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Oxygen concentration profiles in sediment of two ancient lakes: Lake Baikal (Siberia, Russia) and Lake Malawi (East Africa)
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Palaega rugosa, a new species of fossil isopod (Crustacea) from Maastrichtian rocks of Tunisia.
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Palaeoenvironmental and sea sevel changes during the early to mid-Holocene in eastern Saudi Arabia and their implications for Neolithic populations
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RBINS Staff Publications 2020
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Palaeogenomic analysis of black rat (Rattus rattus) reveals multiple European introductions associated with human economic history
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The distribution of the black rat (Rattus rattus) has been heavily influenced by its association with humans. The dispersal history of this non-native commensal rodent across Europe, however, remains poorly understood, and different introductions may have occurred during the Roman and medieval periods. Here, in order to reconstruct the population history of European black rats, we first generate a de novo genome assembly of the black rat. We then sequence 67 ancient and three modern black rat mitogenomes, and 36 ancient and three modern nuclear genomes from archaeological sites spanning the 1st-17th centuries CE in Europe and North Africa. Analyses of our newly reported sequences, together with published mitochondrial DNA sequences, confirm that black rats were introduced into the Mediterranean and Europe from Southwest Asia. Genomic analyses of the ancient rats reveal a population turnover in temperate Europe between the 6th and 10th centuries CE, coincident with an archaeologically attested decline in the black rat population. The near disappearance and re-emergence of black rats in Europe may have been the result of the breakdown of the Roman Empire, the First Plague Pandemic, and/or post-Roman climatic cooling.
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RBINS Staff Publications 2022
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Palaeogenomics of Upper Palaeolithic to Neolithic European hunter-gatherers
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Modern humans have populated Europe for more than 45,000 years1,2. Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period3. Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe4, but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants.
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RBINS Staff Publications 2023
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Palaeogeographical and palaeoecological constraints on palaeozoic vertebrates (chondrichthyans and placoderms) in the Ardenne Massif - Shark radiations in the Famennian on both sides of the Palaeotethys
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Three chondrichthyan radiations are registered in the Famennian of the ArdenneMassif (Belgium). These radiations are already observed in Morocco and in the Carnic Alps, their acme being related with the early expansa transgression. Comparisons of univariate statistical descriptors like Margalef richness and Shannon–Wiener diversity index show variations between both margins of the Paleotethys, variations interpreted in terms of trophic relationships. The Ardenne area, a northern shallow carbonate platform is characterized during the Famennian by endemic shark taxa with durophagous dentition. The southern open deep-sea area, the Variscan Sea, contains large placoderms probably disclosing a negative feedback on “cladodont” chondrichthyans. This supports the hypothesis that the Armorica platelet behaved like a barrier between the central southern Laurussia and northern Gondwana.
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