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The variability observed in the growing Middle Pleistocene hominin fossil record of Europe continues to trigger much debate on taxonomic issues and the biological processes that gave rise to Neanderthals. Here we present a metric and morphological comparative study of the dental samples recovered from the sites of Arago (southeast France) and Sima de los Huesos (SH) in the Sierra de Atapuerca (northern Spain). These sites are key to providing answers to these questions since they have yielded the largest hominin samples so far recovered for this time period. Despite the geographical proximity of the two sites and the contemporaneity of their hominin assemblages, we have observed remarkable metric and morphological differences between the teeth at Arago and SH. Whereas the SH teeth present an almost morphological identity with European Neanderthals, the Arago teeth exhibit a combination of plesiomorphic as well as some Neanderthal-derived features. In addition, the Arago crown dimensions are remarkably larger than those from SH, the differences being statistically significant for most variables. We hypothesize that during the Middle Pleistocene the European continent was settled at different points in time by hominin groups coming from Southwest Asia, probably from a common mother population evolving in this latter region. These first settlers can be identified by their more plesiomorphic morphology, whereas the most recent settlers are closer in appearance to Neanderthals. In addition, genetic processes such as isolation, genetic drift, directional adaptation or hybridization would have given rise to the puzzle we observe in the current fossil record.

One of the most interesting aspects of the settlement of Europe is the possible continuity or discontinuity of the populations living in this continent during the Early and Middle Pleistocene. In this paper we present an analysis of the mandibular fossil record from four important Pleistocene European sites, Gran Dolina-TD6-2 (Sierra de Atapuerca), Mauer, Arago, and Atapuerca-Sima de los Huesos. We focus this study in the recognition of key derived mandibular features that may be useful to assess the relationship among the populations represented at these sites. In order to make an approach to the ecological scenario, we also present a short review and discussion of the archaeological and paleoenvironmental evidences at that time. Our results suggest that probably there was a demographic discontinuity between the late Early Pleistocene populations (MIS 21-MIS 19), and those dated to the MIS 15. Hybridization between residents and new settlers cannot be discarded. However, some features of the Gran Dolina-TD6 hominins point to some relationship between the population represented in this site (probably dated to the MIS 21) and the European Middle Pleistocene and early Late Pleistocene populations. A hypothetical scenario is presented in order to understand this apparent contradiction with the model of discontinuity.

The Iberian lynx, endemic to the Iberian Peninsula, is the most threatened carnivore in Europe and the most endangered felid in the world. Widely distributed throughout Iberia during the Pleistocene and Holocene it is now confined to two small populations in southern Spain. Lynx species differentiation, based solely on morphological analysis from skeletal traits, is a difficult task and can potentially lead to misidentification. In order to verify whether Iberian lynx had a wider geographical distribution in the past, we successfully sequenced 152 base pairs (bp) of the cytochrome b gene and 183 bp of the mitochondrial control region in 20 Late Pleistocene and Holocene fossil remains of Lynx sp. from southern Europe. Our results confirm the presence of Iberian lynx outside the Iberian Peninsula demonstrating that this is a palaeoendemic species that had a wider distribution range in southern Europe during the Holocene and the Late Pleistocene. In addition, we documented the presence of both Palaearctic extant lynx species in the Arene Candide (north Italy) site during the Last Glacial Maximum.

The environmental conditions that existed during the period between 45 and 30 ka are of vital importance for addressing the transition between the Middle and Upper Paleolithic. It seems to be a hiatus of Paleolithic populations, a “no (hu)man’s land” in Central Iberia, coinciding with the mid part of Marine Isotope Stage (MIS) 3, between 42 and 28 cal kyr BP. This break in the archaeological record makes it difficult to address this period paleoecologically. Here we present a new cave site, Portalon del Tejadilla (Segovia), dated to a period roughly between ∼34.2 and 40.4 cal kyr BP in which cold-adapted faunas, such as woolly rhinoceros and giant deer, have been recovered in a hyena den site context. This site is located in Central Iberia, and more specifically, on the southern edge of the northern Plateau, an unexpected region for the presence of these faunas during the MIS 3. These new findings extend the geographical distribution of several species, including Coelodonta antiquitatis and Megaloceros giganteus. Furthermore, they document a climatic deterioration (colder and dryer) during the mid MIS 3 in Central Iberia in one of the coldest and driest episodes of the Late Pleistocene. Portalon del Tejadilla fills this temporal gap and provides valuable paleoecological information about the transition between the Middle to Upper Paleolithic.

The Sima de los Huesos (SH) site is the largest accumulation of human remains from the Middle Pleistocene known to date. Studies in the last two decades have proposed different hypotheses to explain carnivore activity in the SH human sample. This study provides new data in order to test these different interpretations, and therefore to understand the role of the carnivores in site formation at SH. Carnivores are usually not the origin of large accumulations of hominin fossils in the Eurasian record. The results show that marks of carnivore activity in the SH sample appear very infrequently, which we interpret as indicating that carnivore activity was very sporadic at the site. This is in stark contrast with previous studies. The comparison of bone modification patterns at SH to actualistic carnivore data allows us to suggest that bears were likely to have been the carnivore responsible for the modification observed on both human and bear fossils.

Pleistocene level TD6-2 of the Gran Dolina site (Sierra de Atapuerca, Spain) is the result of anthropogenic accumulation. Hominin groups occupied the cave as a home base, where they brought in, butchered and consumed the carcasses of ungulates and other hominins. In this paper, we reassess the role of carnivores in the formation and/or modification of the assemblage. We employed different methods to explore the scenario in which the TD6-2 assemblage was formed: (1) identifying the actor responsible for tooth marks; (2) determining the frequency of carnivore tooth marks and their distribution; (3) identifying the co-occurrence of modifications (butchering marks and carnivore tooth marks); (4) calculating the percentage of change and the epiphysis to shaft ratio. Carnivore tooth marks are scarce, as is the co-occurrence of hominin and carnivore modifications. However, not all tooth marks have been attributed to a particular agent due to the high equifinality between human and carnivore tooth marks. For these reasons, the frequency of tooth marks and the co-occurrence of modifications have been of little help in interpreting the role of carnivores. Axial skeletal remains and the epiphyses of the long bones are in large part missing. The percentage of change and the epiphysis to shaft ratio suggest moderate carnivore ravaging activity. Our data indicate that the role of carnivores in TD6-2 seems to have had an impact on the original assemblage after hominins had extracted a large amount of nutrients from the carcasses. Cannibalized hominin remains showed no carnivore tooth marks and have a greater presence of low survival bones compared to ungulate remains. These findings point to a different taphonomic history suggesting that TD6-2 represents a succession of settlements having different characteristics.

The suggestion that the Neanderthal linage hominids had predominantly rich diet in meat derived from large game is progressing towards views which propose a higher nutritional diversity, at least in some regions. These postulates situate hominids as the knower of their natural surroundings and make them capable of selecting within the range of resources available in their landscapes. Using a zooarchaeological approach, the taxonomical representation in an anthropogenic site could indicate both the environment diversity that human groups can exploit and the decisions that they make when selecting prey. The Optimal Foraging theory is a basic decision model that is ideally applied within a larger framework of constraining conditions such as differential prey distributions, food-consumer imbalances and/or competition, among others. Nevertheless, if this theory is applied to human behaviour, uncontrolled variables could exist and substantially alter some predictions. These variables may not always be related to the need to optimise the resources; additionally, they can respond to the questions related to nutritional ecology, cultural standards or social relationships conditioned by ecological or technological factors. Environmental and socio-cultural aspects invite us to reflect on the characteristics that delimit the pre-Upper Palaeolithic diet and its correct assessment in relation to the availability of prey in the environment and the human behavioural parameters. In this study, we present data from several levels of Bolomor Cave (Valencia, Spain, MIS 9-5e) and a sample from the TD10-1 sublevel of Gran Dolina (Sierra de Atapuerca, Burgos, Spain, MIS 9). Both sites have been interpreted as habitat places and allow us to infer the high plasticity of human groups with respect to methods and techniques of acquisition and use of a diverse spectrum of prey. Environmental availability, duration and type of settlement seem to significantly influence the taxonomical representation and must be taken into account when assessing diet breadth in these chronologies. We must add to these factors, human behavioural variables related to social and cultural aspects. Using this approach, we highlight the high variability in the subsistence strategies developed by hominids in the European Middle Pleistocene and propose several factors to consider when examining the early use of small prey.

Interpreting how environmental dynamics respond to global climate change and how this has affected human evolution and dispersal is an on-going topic of debate. During the early Middle Pleistocene (∼0.6–0.4 Ma), as compared to earlier, environmental conditions were relatively more stable, with longer climatic cycles alternating between open and forested landscapes. During this interval, humans spread successfully providing an important number of fossil sites where fossils or tools are reported. The Atapuerca-Sima de los Huesos (Burgos, northern Spain) site (Atapuerca-SH) is one of the earliest localities with hominin evidence in the European Middle Pleistocene, with the most important accumulation of Homo heidelbergensis so far. We have analyzed the abundant faunal record from Sima de los Huesos, which is mainly comprised of carnivores, in order to approach an interpretation of the palaeoenvironmental circumstances where these hominids inhabited within the Sierra. Other sites from Sierra de Atapuerca referred to the same Faunal Unit (FU 6), are roughly contemporaneous, and include important ungulates, which are here analyzed with Atapuerca-SH. Additional information provided by isotopic analysis helps elucidate the ancient ecology of taxa present in Sima de los Huesos allowing for an accurate portrayal of the setting in which humans lived. The timing of the spread of Homo heidelbergensis is dominated by a relative climatic and environmental stability and points to a landscape dominated by savannah-like open woodland.