24 research outputs found

    Evolution, systematics, and phylogeography of Pleistocene horses in the new world: A molecular perspective

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    The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the "stilt-legged" horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.Instituto Multidisciplinario de Biología CelularFacultad de Ciencias Naturales y Muse

    Species-specific responses of Late Quaternary megafauna to climate and humans

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    Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary remain contentious. We use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, underscoring the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.This paper is in the memory of our friend and colleague Dr. Andrei Sher, who was a major contributor of this study. Dr Sher died unexpectedly, but his major contributions to the field of Quaternary science will be remembered and appreciated for many years to come. We are grateful to Dr. Adrian Lister and Dr. Tony Stuart for guides and discussions. Thanks to Tina B. Brandt, Dr. Bryan Hockett and Alice Telka for laboratory help and samples and to L. Malik R. Thrane for his work on the megafauna locality database. Data taken from the Stage 3 project was partly funded by Grant #F/757/A from the Leverhulme Trust, together with a grant from the McDonald Grants and Awards Fund. We acknowledge the Danish National Research Foundation, the Lundbeck Foundation, the Danish Council for Independent Research and the US National Science Foundation for financial suppor

    The 10,000-year biocultural history of fallow deer and its implications for conservation policy

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    Over the last 10,000 years, humans have manipulated fallow deer populations with varying outcomes. Persian fallow deer (Dama mesopotamica) are now endangered. European fallow deer (Dama dama) are globally widespread and are simultaneously considered wild, domestic, endangered, invasive, and are even the national animal of Barbuda and Antigua. Despite their close association with people, there is no consensus regarding their natural ranges or the timing and circumstances of their human-mediated translocations and extirpations. Our mitochondrial analyses of modern and archaeological specimens revealed two distinct clades of European fallow deer present in Anatolia and the Balkans. Zooarchaeological evidence suggests these regions were their sole glacial refugia. By combining biomolecular analyses with archaeological and textual evidence, we chart the declining distribution of Persian fallow deer and demonstrate that humans repeatedly translocated European fallow deer, sourced from the most geographically distant populations. Deer taken to Chios and Rhodes in the Neolithic derived not from nearby Anatolia, but from the Balkans. Though fallow deer were translocated throughout the Mediterranean as part of their association with the Greco-Roman goddesses Artemis and Diana, deer taken to Roman Mallorca were not locally available Dama dama, but Dama mesopotamica. Romans also initially introduced fallow deer to Northern Europe but the species became extinct and was reintroduced in the medieval period, this time from Anatolia. European colonial powers then transported deer populations across the globe. We argue that these biocultural histories of fallow deer should underpin modern management strategie

    Cave bears from Southern Germany: Sex ratios and age structure. A contribution towards a better understanding of the paleobiology of Ursus spelaeus

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    Sex ratios of cave bears (Ursus spelaeus and U. deningeri) are known to vary greatly between sites. A number of explanations have been proposed to account for this variability, involving for example cave size, altitude, and the seasonality of food availability. This contribution presents demographic data from three sites in southern Germany which allow the rejection of these models; the factor(s) behind the variability in sex ratios is (are) still unknown. The data also suggest that, contrary to the case in living brown bears (U. arctos), males in cave bears may have reached a very old age more frequently than females.</p

    Les populations de rennes du Tardiglaciaire en Europe centrale et occidentale

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    On sait depuis longtemps que le renne (Rangifer tarandus) était une ressource importante pour les hommes du Tardiglaciaire d\u27une vaste zone géographique, et que les migrations annuelles des rennes, en particulier, étaient un facteur important dans la détermination des mouvements saisonniers et des stratégies de subsistance des populations humaines du passé. À part quelques exceptions, les tentatives pour déterminer les mouvements des troupeaux de rennes se sont cependant basées sur des données saisonnières douteuses (essentiellement la chute des bois) ou sur des suppositions injustifiées sur le comportement des animaux et la taille des troupeaux. Cet article envisage le problème par les données ostéométriques du matériel de Rangifer du Nord et du Sud de l\u27Allemagne, de Suisse et de France. Une tentative est faite pour distinguer d\u27éventuelles populations de rennes dans cette aire géographique. Les résultats montrent clairement une distinction entre le renne "du nord" et le renne "du sud", à la fois dans la taille et dans le degré de dimorphisme sexuel.It has long been recognized that reindeer (Rangifer tarandus) was an important resource for late Paleolithic people over a vast geographical area, and that yearly reindeer migrations in particular were an important factor determining the seasonal movements and subsistence strategies of past human populations. With a few exceptions, however, attempts to determine the movements of the reindeer herds have been based on doubtful seasonal data (mostly antler casting) or on unjustified assumptions about the behaviour of the animals and the size of the herds. This paper tackles this problem with osteometrical data of Rangifer material from northern and southern Germany, Switzerland and France. An attempt is made to distinguish possible reindeer populations in this area. The results show a clear distinction between "northern" and "southern" reindeer, both in their size and in their degree of sexual dimorphism.</p

    Pleistocene brown bears in the mid-continent of North America

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    Current biogeographic models hypothesize that brown bears migrated from Asia to the New World ~100 to 50 thousand years ago but did not reach areas south of Beringia until ~13 to 12 thousand years ago, after the opening of a mid-continental ice-free corridor. We report a 26-thousand-year-old brown bear fossil from central Alberta, well south of Beringia. Mitochondrial DNA recovered from the specimen shows that it belongs to the same clade of bears inhabiting southern Canada and the northern United States today and that modern brown bears in this region are probably descended from populations that persisted south of the southern glacial margin during the Last Glacial Maximum. <br/

    Evolution, systematics and phylogeography of pleistocene horses in the new world: a molecular perspective

    Get PDF
    The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents.Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the “stilt-legged” horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.<br/

    The Late Pleistocene distribution of vicuñas (Vicugna vicugna) and the "extinction" of the gracile llama ("Lama gracilis"): New molecular data

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    We present the results of a palaeogenetic analysis of two Late Pleistocene camelids originating in southern Chile. Our analysis of two mitochondrial DNA fragments (control region and cytochrome b gene) reveals that these specimens do not belong to an extinct taxon, but rather to extant vicuña (Vicugna vicugna), whose modern distribution is restricted to the extreme elevations of the Andes, more than 3500 km to the north of where these specimens originated. Our results also suggest fossil specimens from Patagonia that are currently assigned to the extinct taxon Lama gracilis, may actually belong to V. vicugna, implying a continuous distribution of the latter from the southern tip of South America to the Andes during the Final Pleistocene. The haplotypes of both specimens are not present in modern populations, suggesting a loss of genetic diversity concomitant with the contraction of the vicuña geographical distribution during the Final Pleistocene or early Holocene.<br/
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