A cranium for the earliest Europeans: phylogenetic position of the hominid from Ceprano, Italy

The human fossil evidence unequivocally pertaining to the first inhabitants of Europe at present includes the sample from Atapuerca-TD6 (Spain) and the incomplete adult calvaria discovered near Ceprano, in Southern Latium (Italy). On the basis of regional correlations and a series of absolute dates, the age of the Ceprano hominid is estimated to range between 800 and 900 kilo-annum (ka). In addition, the association with archaic (Mode 1) Paleolithic findings from the same area is suggested. After the completed reconstruction of the calvaria, we present here a new study dealing with the general and more detailed aspects of the morphology displayed by Ceprano, in comparison to fossil samples ranging between Early and Middle Pleistocene. According to our results, cranial features indicate that Ceprano represents a unique morphological bridge between the clade Homo ergaster/erectus and later Middle Pleistocene specimens commonly referred to Homo heidelbergensis (and/or to Homo rhodesiensis), particularly those belonging to the African fossil record that ultimately relates to the origin of modern humans. In conclusion, given its geographical, chronological, and phylogenetic position, an attribution to the species Homo antecessor is considered, although the sample from Atapuerca-TD6 is not directly comparable to Ceprano. Alternatively, a new species-ancestral to later European and African hominines-should be named to accommodate such a unique fossil specimen.     

Middle Pleistocene lower back and pelvis from an aged human individual from the Sima de los Huesos site, Spain

We report a nearly complete lumbar spine from the Middle Pleistocene site of the Sima de los Huesos (SH) that is assigned to the previously published SH male Pelvis 1 [Arsuaga JL, et al. (1999). Nature 399: 255-258]. The "SH Pelvis 1 individual" is a unique nearly complete lumbo-pelvic complex from the human Middle Pleistocene fossil record, and offers a rare glimpse into the anatomy and past lifeways of Homo heidelbergensis. A revised reconstruction of Pelvis 1, together with the current fossil evidence, confirms our previous hypothesis that the morphology of this pelvis represents the primitive pattern within the genus Homo. Here we argue that this primitive pattern is also characterized by sexual dimorphism in the pelvic canal shape, implying complicated deliveries. In addition, this individual shows signs of lumbar kyphotic deformity, spondylolisthesis, and Baastrup disease. This suite of lesions would have postural consequences and was most likely painful. As a result, the individual's daily physical activities would have been restricted to some extent. Reexamination of the age-at-death agrees with this individual being over 45 y old, relying on the modern human pattern of changes of the articular surfaces of the os coxae. The presence of degenerative pathological lesions and the advanced age-at-death of this individual make it the most ancient postcranial evidence of an aged individual in the human fossil record. Additional nonpathological SH lumbo-pelvic remains are consistent with previous hypotheses, suggesting a less-pronounced sagittal spinal curvature in Neandertals compared with Homo sapiens.     

Earliest human occupations at Dmanisi (Georgian Caucasus) dated to 1.85-1.78 Ma

The early Pleistocene colonization of temperate Eurasia by Homo erectus was not only a significant biogeographic event but also a major evolutionary threshold. Dmanisi's rich collection of hominin fossils, revealing a population that was small-brained with both primitive and derived skeletal traits, has been dated to the earliest Upper Matuyama chron (ca. 1.77 Ma). Here we present archaeological and geologic evidence that push back Dmanisi's first occupations to shortly after 1.85 Ma and document repeated use of the site over the last half of the Olduvai subchron, 1.85-1.78 Ma. These discoveries show that the southern Caucasus was occupied repeatedly before Dmanisi's hominin fossil assemblage accumulated, strengthening the probability that this was part of a core area for the colonization of Eurasia. The secure age for Dmanisi's first occupations reveals that Eurasia was probably occupied before Homo erectus appears in the East African fossil record.     

A radiation of arboreal basal eutherian mammals beginning in the Late Cretaceous of India

India's Late Cretaceous fossil mammals include the only undisputed pre-Tertiary Gondwanan eutherians, such as Deccanolestes. Recent studies have suggested a relationship between Deccanolestes and African and European Paleocene adapisoriculids, which have been variably identified as stem euarchontans, stem primates, lipotyphlan insectivores, or afrosoricids. Support for a close relationship between Deccanolestes and any of these placental mammal clades would be unique in representing a confirmed Mesozoic record of a placental mammal. However, some paleogeographic reconstructions place India at its peak isolation from all other continents during the latest Cretaceous, complicating reconstructions of the biogeographic history of the placental radiation. Recent fieldwork in India has recovered dozens of better-preserved specimens of Cretaceous eutherians, including several new species. Here, we incorporate these new specimens into an extensive phylogenetic analysis that includes every clade with a previously hypothesized relationship to Deccanolestes. Our results support a robust relationship between Deccanolestes and Paleocene adapisoriculids, but do not support a close affinity between these taxa and any placental clade, demonstrating that Deccanolestes is not a Cretaceous placental mammal and reinforcing the sizeable gap between molecular and fossil divergence time estimates for the placental mammal radiation. Instead, our expanded data push Adapisoriculidae, including Deccanolestes, into a much more basal position than in earlier analyses, strengthening hypotheses that scansoriality and arboreality were prevalent early in eutherian evolution. This comprehensive phylogeny indicates that faunal exchange occurred between India, Africa, and Europe in the Late Cretaceous-Early Paleocene, and suggests a previously unrecognized ～30 to 45 Myr "ghost lineage" for these Gondwanan eutherians.     

Early human occupation of Western Europe: paleomagnetic dates for two paleolithic sites in Spain

The lacustrine deposits infilling the intramontane Guadix-Baza Basin, in the Betic Range of Southern Spain, have yielded abundant well-preserved lithic artifacts. In addition, the lake beds contain a wide range of micromammals including Mimomys savini and Allophaiomys burgondiae and large mammals such as Mammuthus and Hippopotamus together with the African saber-toothed felid Megantereon. The association of the lithic artifacts along with the fossil assemblages, themselves of prime significance in the Eurasian mammal biochronology, is providing new insight into the controversy of the human settlement in Southern Europe. Despite the importance of the artifacts and fossil assemblage, estimates of the geological age of the site are still in conflict. Some attempts at dating the sediments have included biochronology, uranium series, amino acid racemization, and stratigraphic correlation with other well-dated sections in the basin, but so far have failed to yield unambiguous ages. Here we present paleomagnetic age dating at the relevant localities and thus provide useful age constraints for this critical paleoanthropological and mammal site. Our data provide firm evidence for human occupation in Southern Europe in the Lower Pleistocene, around 1 mega-annum ago. The current view of when and how hominids first dispersed into Europe needs to be reevaluated.     

Detecting genetic drift versus selection in human evolution

Recent paleoanthropological discoveries reveal a diverse, potentially speciose human fossil record. Such extensive morphological diversity results from the action of divergent evolutionary forces on an evolving lineage. Here, we apply quantitative evolutionary theory to test whether random evolutionary processes alone can explain the morphological diversity seen among fossil australopith and early Homo crania from the Plio-Pleistocene. We show that although selection may have played an important role in diversifying hominin facial morphology in the late Pliocene, this is not the case during the early evolution of the genus Homo, where genetic drift was probably the primary force responsible for facial diversification.     

An Early Pleistocene hominin mandible from Atapuerca-TD6, Spain

We present a mandible recovered in 2003 from the Aurora Stratum of the TD6 level of the Gran Dolina site (Sierra de Atapuerca, northern Spain). The specimen, catalogued as ATD6-96, adds to the hominin sample recovered from this site in 1994-1996, and assigned to Homo antecessor. ATD6-96 is the left half of a gracile mandible belonging to a probably female adult individual with premolars and molars in place. This mandible shows a primitive structural pattern shared with all African and Asian Homo species. However, it is small and exhibits a remarkable gracility, a trait shared only with the Early and Middle Pleistocene Chinese hominins. Furthermore, none of the mandibular features considered apomorphic in the European Middle and Early Upper Pleistocene hominin lineage are present in ATD6-96. This evidence reinforces the taxonomic identity of H. antecessor and is consistent with the hypothesis of a close relationship between this species and Homo sapiens.     

The origin of Neandertals

Western Eurasia yielded a rich Middle (MP) and Late Pleistocene (LP) fossil record documenting the evolution of the Neandertals that can be analyzed in light of recently acquired paleogenetical data, an abundance of archeological evidence, and a well-known environmental context. Their origin likely relates to an episode of recolonization of Western Eurasia by hominins of African origin carrying the Acheulean technology into Europe around 600 ka. An enhancement of both glacial and interglacial phases may have played a crucial role in this event, as well as in the subsequent evolutionary history of the Western Eurasian populations. In addition to climatic adaptations and an increase in encephalization, genetic drift seems to have played a major role in their evolution. To date, a clear speciation event is not documented, and the most likely scenario for the fixation of Neandertal characteristics seems to be an accretion of features along the second half of the MP. Although a separation time for the African and Eurasian populations is difficult to determine, it certainly predates OIS 11 as phenotypic Neandertal features are documented as far back as and possibly before this time. It is proposed to use the term “Homo rhodesiensis” to designate the large-brained hominins ancestral to H. sapiens in Africa and at the root of the Neandertals in Europe, and to use the term “Homo neanderthalensis” to designate all of the specimens carrying derived metrical or non-metrical features used in the definition of the LP Neandertals.     

Earliest evidence of modern human life history in North African early Homo sapiens

Recent developmental studies demonstrate that early fossil hominins possessed shorter growth periods than living humans, implying disparate life histories. Analyses of incremental features in teeth provide an accurate means of assessing the age at death of developing dentitions, facilitating direct comparisons with fossil and modern humans. It is currently unknown when and where the prolonged modern human developmental condition originated. Here, an application of x-ray synchrotron microtomography reveals that an early Homo sapiens juvenile from Morocco dated at 160,000 years before present displays an equivalent degree of tooth development to modern European children at the same age. Crown formation times in the juvenile's macrodont dentition are higher than modern human mean values, whereas root development is accelerated relative to modern humans but is less than living apes and some fossil hominins. The juvenile from Jebel Irhoud is currently the oldest-known member of Homo with a developmental pattern (degree of eruption, developmental stage, and crown formation time) that is more similar to modern H. sapiens than to earlier members of Homo. This study also underscores the continuing importance of North Africa for understanding the origins of human anatomical and behavioral modernity. Corresponding biological and cultural changes may have appeared relatively late in the course of human evolution.     

Evolutionary basis for the human diet: consequences for human health

The relationship of evolution with diet and environment can provide insights into modern disease. Fossil evidence shows apes, and early human ancestors were fruit eaters living in environments with strongly seasonal climates. Rapid cooling at the end of the Middle Miocene (15–12 Ma: millions of years ago) increased seasonality in Africa and Europe, and ape survival may be linked with a mutation in uric acid metabolism. Climate stabilized in the later Miocene and Pliocene (12–5 Ma), and fossil apes and early hominins were both adapted for life on ground and in trees. Around 2.5 Ma, early species of Homo introduced more animal products into their diet, and this coincided with developing bipedalism, stone tool technology and increase in brain size. Early species of Homo such as Homo habilis still lived in woodland habitats, and the major habitat shift in human evolution occurred at 1.8 Ma with the origin of Homo erectus. Homo erectus had increased body size, greater hunting skills, a diet rich in meat, control of fire and understanding about cooking food, and moved from woodland to savannah. Group size may also have increased at the same time, facilitating the transmission of knowledge from one generation to the next. The earliest fossils of Homo sapiens appeared about 300 kyr, but they had separated from Neanderthals by 480 kyr or earlier. Their diet shifted towards grain‐based foods about 100 kyr ago, and settled agriculture developed about 10 kyr ago. This pattern remains for many populations to this day and provides important insights into current burden of lifestyle diseases.     

Rates of anterior tooth wear in Middle Pleistocene hominins from Sima de los Huesos (Sierra de Atapuerca, Spain)

This study presents quantitative data on the rates of anterior tooth wear in a Pleistocene human population. The data were obtained for the hominin sample of the Sima de los Huesos site in Atapuerca, Spain. The fossil record belongs to a minimum of 28 individuals of the same biological population, assigned to the species Homo heidelbergensis. We have estimated the original and the preserved crown height of the mandibular incisors (I1 and I2) of 11 individuals, whose age at death can be ascertained from the mineralization stage and tooth eruption. Results provide a range of 0.276-0.348 and 0.288-0.360 mm per year for the mean wear rate of the mandibular I1 and I2, respectively, in individuals approximately 16-18 years old. These data suggest that incisors' crowns would be totally worn out toward the fifth decade of life. Thus, we expect the life expectancy of this population to be seriously limited. These data, which could be contrasted with results obtained on hominins at other sites, could be of interest for estimating the death age of adult individuals.     

A modern human pattern of dental development in lower pleistocene hominids from Atapuerca-TD6 (Spain)

The study of life history evolution in hominids is crucial for the discernment of when and why humans have acquired our unique maturational pattern. Because the development of dentition is critically integrated into the life cycle in mammals, the determination of the time and pattern of dental development represents an appropriate method to infer changes in life history variables that occurred during hominid evolution. Here we present evidence derived from Lower Pleistocene human fossil remains recovered from the TD6 level (Aurora stratum) of the Gran Dolina site in the Sierra de Atapuerca, northern Spain. These hominids present a pattern of development similar to that of Homo sapiens, although some aspects (e.g., delayed M3 calcification) are not as derived as that of European populations and people of European origin. This evidence, taken together with the present knowledge of cranial capacity of these and other late Early Pleistocene hominids, supports the view that as early as 0.8 Ma at least one Homo species shared with modern humans a prolonged pattern of maturation.     

An early modern human from the Peştera cu Oase, Romania

The 2002 discovery of a robust modern human mandible in the Pe?tera cu Oase, southwestern Romania, provides evidence of early modern humans in the lower Danubian Corridor. Directly accelerator mass spectrometry radiocarbon (14C)-dated to 34,000-36,000 14C years B.P., the Oase 1 mandible is the oldest definite early modern human specimen in Europe and provides perspectives on the emergence and evolution of early modern humans in the northwestern Old World. The moderately long Oase 1 mandible exhibits a prominent tuber symphyseos and overall proportions that place it close to earlier Upper Paleolithic European specimens. Its symmetrical mandibular incisure, medially placed condyle, small superior medial pterygoid tubercle, mesial mental foramen, and narrow corpus place it closer to early modern humans among Late Pleistocene humans. However, its cross-sectional symphyseal orientation is intermediate between late archaic and early modern humans, the ramus is exceptionally wide, and the molars become progressively larger distally with exceptionally large third molars. The molar crowns lack derived Neandertal features but are otherwise morphologically undiagnostic. However, it has unilateral mandibular foramen lingular bridging, an apparently derived Neandertal feature. It therefore presents a mosaic of archaic, early modern human and possibly Neandertal morphological features, emphasizing both the complex population dynamics of modern human dispersal into Europe and the subsequent morphological evolution of European early modern humans.     

Morphological and functional stasis in mycorrhizal root nodules as exhibited by a Triassic conifer

Mycorrhizal root nodules occur in the conifer families Araucariaceae, Podocarpaceae, and Sciadopityaceae. Although the fossil record of these families can be traced back into the early Mesozoic, the oldest fossil evidence of root nodules previously came from the Cretaceous. Here we report on cellularly preserved root nodules of the early conifer Notophytum from Middle Triassic permineralized peat of Antarctica. These fossil root nodules contain fungal arbuscules, hyphal coils, and vesicles in their cortex. Numerous glomoid-type spores are found in the peat matrix surrounding the nodules. This discovery indicates that mutualistic associations between conifer root nodules and arbuscular mycorrhizal fungi date back to at least the early Mesozoic, the period during which most of the modern conifer families first appeared. Notophytum root nodules predate the next known appearance of this association by 100 million years, indicating that this specialized form of mycorrhizal symbiosis has ancient origins.     

Early Cretaceous mammal from North America and the evolution of marsupial dental characters.

A mammal from the Early Cretaceous of the western United States, represented by a lower jaw exceptional in its completeness, presents unambiguous evidence of postcanine dental formula in an Early Cretaceous marsupial-like mammal, and prompts a reconsideration of the early evolution of marsupial dental characters. A marsupial postcanine dental formula (three premolars and four molars) and several marsupial-like features of the lower molars are present in the new taxon, but a hallmark specialization of marsupials (twinning of the hypoconulid and entoconid on lower molars) is lacking. This, coupled with recent evidence from the Late Cretaceous of the western United States, suggests that the distinctive marsupial dental formula evolved prior to the most characteristic specialization of lower molars and that apomorphies presumed to be diagnostic of the upper molars (such as auxiliary stylar cusps) were relatively more recent developments in marsupial history. Dental evidence supports the monophyly of higher (tribosphenic) mammals and suggests that the predominantly Old World Deltatheroida, recently proposed as a sister taxon to marsupials, represents a primitive and unrelated group of higher mammals; by this interpretation, early marsupials and their presumed close relatives are restricted to North America. This, together with the hypothesized relationships of South American/Australian marsupials (in the context of the North American Cretaceous radiation) and evidence from the fossil record of South America, in turn supports a North American origin for the group.     

The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography

We report the discovery of mammalian tribosphenic teeth from the basal Cenomanian of southwestern France that we refer to a new primitive marsupial-like form identified as a basal taxon of Marsupialiformes, a new clade recognized here to include the crown group Marsupialia and primitive stem lineages more closely related to Marsupialia than to Deltatheroida. Arcantiodelphys marchandi gen et sp nov. shares several significant marsupial-like features (s.l.) with marsupialiform taxa known from the North American Mid-Cretaceous. Among marsupialiforms, it shows a closer resemblance to Dakotadens. This resemblance, which is plesiomorphic within “tribotherians,” makes Arcantiodelphys one of the most archaic known Marsupialiformes. Moreover, Arcantiodelphys is characterized by an original and precocious crushing specialization. Both the plesiomorphic and autapomorphic characteristics of Arcantiodelphys among Marsupialiformes might be explained by an Eastern origin from Asian stem metatherians, with some in situ European evolution. In addition, the presence of a mammal with North American affinities in western Europe during the early Late Cretaceous provides further evidence of a large Euramerican biogeographical province at this age or slightly before. Concerning the paleobiogeographical history of the first stem marsupialiforms during the Albian–Cenomanian interval, 2 possible dispersal routes from an Asian metatherian ancestry can be proposed: Asia to Europe via North America and Asia to North America via Europe. The main significance of the Archingeay-Les Nouillers mammal discovery is that it indicates that the beginning of the stem marsupialiforms history involved not only North America but also Europe, and that this early history in Europe remains virtually unknown.     

Exceptionally preserved crustaceans from western Canada reveal a cryptic Cambrian radiation

The early history of crustaceans is obscured by strong biases in fossil preservation, but a previously overlooked taphonomic mode yields important complementary insights. Here we describe diverse crustacean appendages of Middle and Late Cambrian age from shallow-marine mudstones of the Deadwood Formation in western Canada. The fossils occur as flattened and fragmentary carbonaceous cuticles but provide a suite of phylogenetic and ecological data by virtue of their detailed preservation. In addition to an unprecedented range of complex, largely articulated filtering limbs, we identify at least four distinct types of mandible. Together, these fossils provide the earliest evidence for crown-group branchiopods and total-group copepods and ostracods, extending the respective ranges of these clades back from the Devonian, Pennsylvanian, and Ordovician. Detailed similarities with living forms demonstrate the early origins and subsequent conservation of various complex food-handling adaptations, including a directional mandibular asymmetry that has persisted through half a billion years of evolution. At the same time, the Deadwood fossils indicate profound secular changes in crustacean ecology in terms of body size and environmental distribution. The earliest radiation of crustaceans is largely cryptic in the fossil record, but "small carbonaceous fossils" reveal organisms of surprisingly modern aspect operating in an unfamiliar biosphere.     

The spread of modern humans in Europe

The earliest credible evidence of Homo sapiens in Europe is an archaeological proxy in the form of several artifact assemblages (Bohunician) found in South-Central and possibly Eastern Europe, dating to ≤48,000 calibrated radiocarbon years before present (cal BP). They are similar to assemblages probably made by modern humans in the Levant (Emiran) at an earlier date and apparently represent a population movement into the Balkans during a warm climate interval [Greenland Interstadial 12 (GI 12)]. A second population movement may be represented by a diverse set of artifact assemblages (sometimes termed Proto-Aurignacian) found in the Balkans, parts of Southwest Europe, and probably in Eastern Europe, and dating to several brief interstadials (GI 11–GI 9) that preceded the beginning of cold Heinrich Event 4 (HE4) (≈40,000 cal BP). They are similar to contemporaneous assemblages made by modern humans in the Levant (Ahmarian). The earliest known human skeletal remains in Europe that may be unequivocally assigned to H. sapiens (Peçstera cu Oase, Romania) date to this time period (≈42,000 cal BP) but are not associated with artifacts. After the Campanian Ignimbrite volcanic eruption (40,000 cal BP) and the beginning of HE4, artifact assemblages assigned to the classic Aurignacian, an industry associated with modern human skeletal remains that seems to have developed in Europe, spread throughout the continent.     

Significance of some previously unrecognized apomorphies in the nasal region of Homo neanderthalensis.

For many years, the Neanderthals have been recognized as a distinctive extinct hominid group that occupied Europe and western Asia between about 200,000 and 30,000 years ago. It is still debated, however, whether these hominids belong in their own species, Homo neanderthalensis, or represent an extinct variant of Homo sapiens. Our ongoing studies indicate that the Neanderthals differ from modern humans in their skeletal anatomy in more ways than have been recognized up to now. The purpose of this contribution is to describe specializations of the Neanderthal internal nasal region that make them unique not only among hominids but possibly among terrestrial mammals in general as well. These features lend additional weight to the suggestion that Neanderthals are specifically distinct from Homo sapiens.     

A northern glacial refugium for bank voles (Clethrionomys glareolus)

There is controversy and uncertainty on how far north there were glacial refugia for temperate species during the Pleistocene glaciations and in the extent of the contribution of such refugia to present-day populations. We examined these issues using phylogeographic analysis of a European woodland mammal, the bank vole (Clethrionomys glareolus). A Bayesian coalescence analysis indicates that a bank vole population survived the height of the last glaciation (approximately 25,000-10,000 years B.P.) in the vicinity of the Carpathians, a major central European mountain chain well north of the Mediterranean areas typically regarded as glacial refugia for temperate species. Parameter estimates from the fitted isolation with migration model show that the divergence of the Carpathian population started at least 22,000 years ago, and it was likely followed by only negligible immigration from adjacent regions, suggesting the persistence of bank voles in the Carpathians through the height of the last glaciation. On the contrary, there is clear evidence for gene flow out of the Carpathians, demonstrating the contribution of the Carpathian population to the colonization of Europe after the Pleistocene. These findings are consistent with data from animal and plant fossils recovered in the Carpathians and provide the clearest phylogeographic evidence to date of a northern glacial refugium for temperate species in Europe.