Climate change in the past has led to significant changes in species' distributions. However, how individual species respond to climate change depends largely on their adaptations and environmental ...tolerances. In the Quaternary, temperate-adapted taxa are in general confined to refugia during glacials while cold-adapted taxa are in refugia during interglacials. In the Northern Hemisphere, evidence appears to be mounting that in addition to traditional southern refugia for temperate species, cryptic refugia existed in the North during glacials. Equivalent cryptic southern refugia, to the south of the more conventional high-latitude polar refugia, exist in montane areas during periods of warm climate, such as the current interglacial. There is also a continental/oceanic longitudinal gradient, which should be included in a more complete consideration of the interaction between species ranges and climates. Overall, it seems clear that there is large variation in both the size of refugia and the duration during which species are confined to them. This has implications for the role of refugia in the evolution of species and their genetic diversity.
The fossil record richly illustrates the origin of morphological adaptation through time. However, our understanding of the selective forces responsible in a given case, and the role of behaviour in ...the process, is hindered by assumptions of synchrony between environmental change, behavioural innovation and morphological response. Here I show, from independent proxy data through a 20-million-year sequence of fossil proboscideans in East Africa, that changes in environment, diet and morphology are often significantly offset chronologically, allowing dissection of the roles of behaviour and different selective drivers. These findings point the way to hypothesis-driven testing of the interplay between habitat change, behaviour and morphological adaptation with the use of independent proxies in the fossil record.
Tooth wear analysis techniques (mesowear and microwear) are employed to analyze dietary traits in proboscideans, perissodactyls and artiodactyls from 33 Pleistocene localities in Britain. The ...objectives of this study are to examine the variability in each taxon, to track dietary shifts through time, and to investigate resource partitioning among species.
The integration of mesowear and microwear results first allowed us to examine dietary variability. We identified differences in variability among species, from more stenotopic species such as Capreolus capreolus to more eurytopic species such as Megaloceros giganteus and Cervus elaphus. Broad dietary shifts at the community level are seen between climatic phases, and are the result of species turnover as well as dietary shifts in the more flexible species. The species present at each locality are generally spread over a large part of the dietary spectrum, and resource partitioning was identified at most of these localities. Mixed feeders always coexist with at least one of the two strict dietary groups, grazers or browsers. Finally, for some species, a discrepancy is observed between meso- and microwear signals and may imply that individuals tended to die at a time of year when their normal food was in short supply.
•Tooth wear analyses are used to infer diet in large herbivores from Pleistocene sites in Britain.•Integration of mesowear and microwear results allowed to examine dietary variability.•The dietary shifts are tracked and examined through time in each taxa.•Interspecific differences are used to investigate resource partitioning among species.
Temporal genomic data hold great potential for studying evolutionary processes such as speciation. However, sampling across speciation events would, in many cases, require genomic time series that ...stretch well back into the Early Pleistocene subepoch. Although theoretical models suggest that DNA should survive on this timescale
, the oldest genomic data recovered so far are from a horse specimen dated to 780-560 thousand years ago
. Here we report the recovery of genome-wide data from three mammoth specimens dating to the Early and Middle Pleistocene subepochs, two of which are more than one million years old. We find that two distinct mammoth lineages were present in eastern Siberia during the Early Pleistocene. One of these lineages gave rise to the woolly mammoth and the other represents a previously unrecognized lineage that was ancestral to the first mammoths to colonize North America. Our analyses reveal that the Columbian mammoth of North America traces its ancestry to a Middle Pleistocene hybridization between these two lineages, with roughly equal admixture proportions. Finally, we show that the majority of protein-coding changes associated with cold adaptation in woolly mammoths were already present one million years ago. These findings highlight the potential of deep-time palaeogenomics to expand our understanding of speciation and long-term adaptive evolution.
In the otherwise excellent special issue of Trends in Ecology and Evolution on long-term ecological research (TREE 25(10), 2010), none of the contributors mentioned the importance of natural history ...collections (NHCs) as sources of data that can strongly complement past and ongoing survey data. Whereas very few field surveys have operated for more than a few decades, NHCs, conserved in museums and other institutions, comprise samples of the Earth's biota typically extending back well into the nineteenth century and, in some cases, before this time. They therefore span the period of accelerated anthropogenic habitat destruction, climate warming and ocean acidification, in many cases reflecting baseline conditions before the major impact of these factors.
The cave lion,
Panthera spelaea, was widespread across northern Eurasia and Alaska/Yukon during the Late Pleistocene. Both morphology and DNA indicate an animal distinct from modern lions (probably ...at the species level) so that its disappearance in the Late Pleistocene should be treated as a true extinction. New AMS radiocarbon dates directly on cave lion from across its range, together with published dates from other studies – totalling 111 dates – indicate extinction across Eurasia in the interval ca. 14–14.5
cal ka BP, and in Alaska/Yukon about a thousand years later. It is likely that its extinction occurred directly or indirectly in response to the climatic warming that occurred ca. 14.7
cal ka BP at the onset of Greenland Interstadial 1, accompanied by a spread of shrubs and trees and reduction in open habitats. Possibly there was also a concomitant reduction in abundance of available prey, although most of its probable prey species survived substantially later. At present it is unclear whether human expansion in the Lateglacial might have played a role in cave lion extinction. Gaps in the temporal pattern of dates suggest earlier temporary contractions of range, ca. 40–35
cal ka BP in Siberia (during MIS 3) and ca. 25–20
cal ka BP in Europe (during the ‘Last Glacial Maximum’), but further dates are required to corroborate these. The Holocene expansion of modern lion (
Panthera leo) into south-west Asia and south-east Europe re-occupied part of the former range of
P. spelaea, but the Late Pleistocene temporal and geographical relationships of the two species are unknown.
ABSTRACT
Proboscideans, and elephants in particular, played a key role in Pleistocene mammal communities in Europe. The British Pleistocene fossil record provides a unique opportunity to study ...changes in proboscidean feeding ecology associated with environmental proxy data such as pollen records and the presence of competitors. Here we utilize a recently introduced dietary analysis method, mesowear angle analysis, for studying relationships between dietary variation in proboscideans, changes in available vegetation and the presence of sympatric proboscidean species. The method is based on recording the relief of worn molar surfaces as angle measurements, which reflect attrition‐ vs. abrasion‐dominated feeding and serve as a proxy for grazing vs. browsing diets. By comparison with pollen records, we show that blunt mesowear angles specifically reflect grass eating rather than open‐ground feeding in general. We further find that all British Pleistocene proboscidean species were relatively flexible feeders able to shift their dietary preference according to local vegetation composition. Nonetheless, when more than one proboscidean species occurred in the same environment, they always show significantly different mean mesowear signal, suggesting dietary niche separation.
Large-scale fluctuations in global climate and resulting changes in ecology had a profound effect on human evolution and dispersal. Though hominin remains are scarce, studies focussing on the more ...abundant records of fossil land mammal communities can contribute greatly to our knowledge of the palaeoenvironmental circumstances that influenced and directed the global spread of hominins. To produce a comprehensive and accurate account of the evolution of western Palaearctic habitat diversity between 2.6 and 0.4
Ma BP, information generated from large mammal communities from 221 key sites has been included in this study.
The palaeoecological conditions of the western Palaearctic during the Early and early Middle Pleistocene were principally controlled by the following key factors: (1) a widespread trend of temperature decrease, (2) the periodicity of the global temperature record, (3) the intensity of single climatic stages, (4) the temporal pattern of climatic variation, (5) geographical position, and (6) the distribution of continental water resources. A general picture of the evolution of western Palaearctic habitat diversity saw the replacement of extensive forested terrain by an alternating sequence of varied savannah-like and forested habitats during the 2.6–1.8
Ma span, as well as an alternation between different types of predominantly open habitats between 1.8 and 1.2
Ma. Both of these processes were governed by 41
ka temperature periodicity. During the 1.2–0.9
Ma time span, irregular climatic fluctuations were more common and habitat variability increased. The subsequent 0.9–0.4
Ma interval, a period controlled by 100
ka periodicity, was by comparison more stable, with longer climatic cycles alternating between open and forested landscapes. During the entire Early and early Middle Pleistocene, assemblages of large mammal communities reveal a distinct trend of decreasing continentality between Eastern and South-Eastern Europe on the one hand, and South-Western and North-Western Europe on the other. This trend was due to the effect of the Atlantic Ocean, while in Southern Europe the relatively low continentality was balanced by influences from the Mediterranean Sea.
When plotted against evidence of hominin occurrence, the data on western Palaearctic habitat diversity inferred from large mammal communities indicate clear environmental stimuli for the earliest human dispersal in Europe. These are: (1) a wide range of habitats, implying a high diversity of resources; (2) mild climates with low seasonality, implying a lack of strong environmental fluctuations. Around 1.8
Ma at the latest, hominins of African origin entered the western Palaearctic for the first time, taking advantage of the diversity of habitats and resources, particularly along large river systems. Their subsequent westward spread between 1.7 and 1.3
Ma was restricted to Mediterranean-influenced areas, which offered a high variability of habitats and relatively low seasonality. The increase in environmental diversity, which occurred from 1.2
Ma onwards, opened up South-Eastern and Eastern Europe for hominin occupation. According to the available records, North-Western and Central Europe were initially colonized during late Early to early Middle Pleistocene interglacials, when these regions experienced periods of low seasonality and considerable habitat diversity.
The use of elephant ivory as a commodity is a factor in declining elephant populations. Despite recent worldwide elephant ivory trade bans, mammoth ivory trade remains unregulated. This complicates ...law enforcement efforts, as distinguishing between ivory from extant and extinct species requires costly, destructive and time consuming methods. Elephant and mammoth ivory mainly consists of dentine, a mineralized connective tissue that contains an organic collagenous component and an inorganic component of calcium phosphate minerals, similar in structure to hydroxyapatite crystals. Raman spectroscopy is a non-invasive laser-based technique that has previously been used for the study of bone and mineral chemistry. Ivory and bone have similar biochemical properties, making Raman spectroscopy a promising method for species identification based on ivory. This study aimed to test the hypothesis that it is possible to identify differences in the chemistry of mammoth and elephant ivory using Raman spectroscopy. Mammoth and elephant tusks were obtained from the Natural History Museum in London, UK. Included in this study were eight samples of ivory from Mammuthus primigenius, two samples of carved ivory bangles from Africa (Loxodonta species), and one cross section of a tusk from Elephas maximus. The ivory was scanned using an inVia Raman micro spectrometer equipped with a x50 objective lens and a 785nm laser. Spectra were acquired using line maps and individual spectral points were acquired randomly or at points of interest on all samples. The data was then analysed using principal component analysis (PCA) with use of an in-house MATLAB script. Univariate analysis of peak intensity ratios of phosphate to amide I and III peaks, and carbonate to phosphate peaks showed statistical differences (p<0.0001) in the average peak intensity ratios between Mammuthus primigenius, Loxodonta spp. and Elephas maximus. Full width at half maximum hight (FWHM)analysis of the phosphate peak demonstrated higher crystal maturity of Mammuthus primigenius compared to living elephant species. The results of the study have established that spectra acquired by Raman spectroscopy can be separated into distinct classes through PCA. In conclusion, this study has shown that well-preserved mammoth and elephant ivory has the potential to be characterized using Raman spectroscopy, providing a promising method for species identification. The results of this study will be valuable in developing quick and non-destructive methods for the identification of ivory, which will have direct applications in archaeology and the regulation of international trade.
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