The Spine of Late Homo

Dental data are one of the most important sources of information on the evolution of ancient hominids. It preserves information about both the early stages of ontogenesis and the postnatal period of life. It is generally accepted that one of the main evolutionary trend within the genus Homo over the past two million years was reduction of teeth size. This trend substantially accelerated in modern Homo sapiens during the Upper Paleolithic and Neolithic. It is assumed that a number of factors could influence the teeth reduction process. However, no detailed understanding of its patterns, limits and chronological and territorial variability has been revealed so far. In this study, we analyze the variability of the upper second molar sizes in Neanderthals, Denisovans, Homo antecessor, Middle Pleistocene Homo from Sierra de Atapuerca (Gran Dolina), Homo erectus, Middle and Late Pleistocene Homo from China other than H. erectus, and compare them with the characteristics of the modern H. sapiens. The main goal of our analysis was to identify local chronological and geographical patterns in the evolution of the size of the second upper molars and assess their compliance with the general epochal trend. The results of the analysis showed that before the appearance of the Upper Paleolithic H. sapiens, two distinct local trends existed on the territory of Eurasia. The first trend, which can be detected in the European pre-sapiens humans, was a decrease in the molar size of the upper second molars. The second one, which got spread in the Middle Pleistocene in Asia, on the contrary, consisted of a sharp increase of the molar size, which formed the morphological specificity of the Denisovan lineage. No stable geographic differentiations of the size of the upper second molars are observed within H. sapiens sample.

Analyse phylogénétique des Hominidés de la Sierra de Atapuerca (Sima de los Huesos et Gran Dolina TD-6): l'évidence crânienne

Gran Dolina-TD6 versus Sima de los Huesos dental samples from Atapuerca: evidence of discontinuity in the European Pleistocene population?

Inner morphological and metric characterization of the molar remains from the Montmaurin-La Niche mandible: The Neanderthal signal

La séquence des rongeurs (Mammalia) des sites du Pléistocène inférieur et moyen d' Atapuerca (Burgos, Espagne)

The sites of Atapuerca are well known for their hominin-bearing localities of Early to Middle Pleistocene age. Trinchera Dolina yields western Europe’s oldest fossil hominin, the 850 ka Homo antecessor ; and at Sima de los Huesos there occurs the best collection of the Middle Pleistocene hominin Homo heidelbergensis . However, small mammals (Rodentia, Insectivora, Chiroptera and Lagomorpha) represent the largest number of species and greatest fossil abundance in the deposits of the Atapuerca cave complex. The small mammals are grouped by habitat categories, but because the ecology of mammals is complex, we base our study on the evolution of these categories throughout the sequence. The assemblage distribution at the Trinchera Dolina site reflects landscape and environmental changes during the past million years. Shifts between woodland, open land and moorland are indicated by the relative abundance of species based on diagnostic elements such as first lower molars. These data are combined with the distribution of large mammals, pollen, sediments and geological context of the Trinchera Dolina site. From this interdisciplinary approach, we conclude that the first hominins from western Europe ( Homo antecessor ) lived during a warm, wet and wooded interval, probably corresponding to Marine Isotope Stages 21 to 19. The transition from Early to Middle Pleistocene at Atapuerca is characterized by palaeoenvironmental changes recorded between levels TD5–6 and TD8–10, respectively. The general opening of the landscape at the beginning of the Middle Pleistocene could have favoured the dispersal of hominins ( Homo heidelbergensis ) across western Europe.

The Bayesian statistical approach considers teeth as forming a developmental module, as opposed to a tooth‐by‐tooth analysis. This approach has been employed to analyze Upper Pleistocene hominins, including Neandertals and some anatomically modern humans, but never earlier populations. Here, we show its application on five hominins from the TD6.2 level of the Gran Dolina site (Homo antecessor, Early Pleistocene) and the Sima de los Huesos site (Middle Pleistocene) of the Sierra de Atapuerca (Burgos, northern Spain). Our results show an advanced development of the third molars in both populations with respect to modern Homo sapiens. In addition, the Sima de los Huesos hominins differ from H. sapiens and H. antecessor in the relatively advanced development of their second molar. The relative mineralization of I1/M1 in H. antecessor appears to be similar to that of modern humans, as opposed to that of Neandertals, which appear to be unique. These observations, combined with reduced enamel formation times and the advanced development of the third molars, appear to indicate a shorter ontogenetic period in the hominins from Gran Dolina and Sima de los Huesos in comparison to modern human average.

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.

The early Middle Pleistocene human material from Boxgrove (West Sussex, UK) consists of a partial left tibia and two lower incisors from a separate adult individual. These remains derive from deposits assigned to the MIS 13 interglacial at about 480 ka and have been referred to as Homo cf. heidelbergensis. The much larger skeletal sample from the Sima de los Huesos (Atapuerca, Spain) is dated to the succeeding MIS 12, at about 430 ka. This fossil material has previously been assigned to Homo heidelbergensis but is now placed within the Neanderthal clade. Because of the scarcity of human remains from the Middle Pleistocene and their morphological variability, this study assessed whether the Boxgrove specimens fit within the morphological variability of the homogeneous Sima de los Huesos population. Based on morphometric analyses performed against 22 lower incisors from Sima de los Huesos and published material, the data from the Boxgrove incisors place them comfortably within the range of Sima de los Huesos. Both assemblages present robust incisors distinct from the overall small recent Homo sapiens incisors, and Boxgrove also aligns closely with Homo neanderthalensis and some other European Middle Pleistocene hominins. Following morphological and cross-sectional analyses of the Boxgrove tibia compared to seven adult Sima de los Huesos specimens and a set of comparative tibiae, Boxgrove is shown to be similar to Sima de los Huesos and Neanderthals in having thick cortices and bone walls, but in contrast resembles modern humans in having a straight anterior tibial crest and a suggestion of a lateral concavity. Based on the patterns observed, there is no justification for assigning the Boxgrove and Sima de los Huesos incisors to distinct paleodemes, but the tibial data show greater contrasts and suggest that all three of these samples are unlikely to represent the same paleodeme.

The Middle Pleistocene hominin mandible from Payre (Ardèche, France)

A sexual dimorphism more marked than in living humans has been claimed for European Middle Pleistocene humans, Neandertals and prehistoric modern humans. In this paper, body size and cranial capacity variation are studied in the Sima de los Huesos Middle Pleistocene sample. This is the largest sample of non-modern humans found to date from one single site, and with all skeletal elements represented. Since the techniques available to estimate the degree of sexual dimorphism in small palaeontological samples are all unsatisfactory, we have used the bootstraping method to asses the magnitude of the variation in the Sima de los Huesos sample compared to modern human intrapopulational variation. We analyze size variation without attempting to sex the specimens a priori. Anatomical regions investigated are scapular glenoid fossa; acetabulum; humeral proximal and distal epiphyses; ulnar proximal epiphysis; radial neck; proximal femur; humeral, femoral, ulnar and tibial shaft; lumbosacral joint; patella; calcaneum; and talar trochlea. In the Sima de los Huesos sample only the humeral midshaft perimeter shows an unusual high variation (only when it is expressed by the maximum ratio, not by the coefficient of variation). In spite of that the cranial capacity range at Sima de los Huesos almost spans the rest of the European and African Middle Pleistocene range. The maximum ratio is in the central part of the distribution of modern human samples. Thus, the hypothesis of a greater sexual dimorphism in Middle Pleistocene populations than in modern populations is not supported by either cranial or postcranial evidence from Sima de los Huesos.

A sexual dimorphism more marked than in living humans has been claimed for European Middle Pleistocene humans, Neandertals and prehistoric modern humans. In this paper, body size and cranial capacity variation are studied in the Sima de los Huesos Middle Pleistocene sample. This is the largest sample of non-modern humans found to date from one single site, and with all skeletal elements represented. Since the techniques available to estimate the degree of sexual dimorphism in small palaeontological samples are all unsatisfactory, we have used the bootstraping method to asses the magnitude of the variation in the Sima de los Huesos sample compared to modern human intrapopulational variation. We analyze size variation without attempting to sex the specimens a priori. Anatomical regions investigated are scapular glenoid fossa; acetabulum; humeral proximal and distal epiphyses; ulnar proximal epiphysis; radial neck; proximal femur; humeral, femoral, ulnar and tibial shaft; lumbosacral joint; patella; calcaneum; and talar trochlea. In the Sima de los Huesos sample only the humeral midshaft perimeter shows an unusual high variation (only when it is expressed by the maximum ratio, not by the coefficient of variation). In spite of that the cranial capacity range at Sima de los Huesos almost spans the rest of the European and African Middle Pleistocene range. The maximum ratio is in the central part of the distribution of modern human samples. Thus, the hypothesis of a greater sexual dimorphism in Middle Pleistocene populations than in modern populations is not supported by either cranial or postcranial evidence from Sima de los Huesos. Am J Phys Anthropol 106:19–33, 1998. © 1998 Wiley-Liss, Inc.

For paleoanthropologists working in the Middle Pleistocene, these are interesting times. New discoveries of artifacts and human fossils have been reported from western Europe, so that it now looks as though this continent was populated 800,000 years ago, if not earlier. One of the fossils, from Ceprano in Italy, is described as Homo erectus. Whether this ancient species ever reached Europe has been repeatedly questioned, but the Ceprano cranium is complete enough to provide some hard evidence. Other finds from Spain are even more spectacular. The Sima de los Huesos (‘‘Pit of Bones’’) in the Sierra de Atapuerca has yielded a wealth of skeletons that are best interpreted as early Neanderthals, perhaps close to 300,000 years in age. Older but unfortunately more fragmentary remains, also from Atapuerca, display no Neanderthal features and are claimed as representatives of a new species. Homo antecessor will require close study. These European discoveries focus fresh attention on the evidence accumulating from Africa and Asia. Human bones are known from the earlier Middle Pleistocene of Africa at localities such as Bodo in Ethiopia and Broken Hill in Zambia. The crania show anatomical features that distinguish them from Homo erectus. In the Far East, the people at Dali and other sites are also more advanced than Homo erectus, but their affinities to groups in the West are uncertain. This Middle Pleistocene record, still sparse but increasingly well dated, raises important questions. One concerns the fate of Homo erectus in different regions of the Old World. Another is how many distinct species should be recognized among the descendants of this ancient lineage. It is apparent that the traditional approach of lumping diverse humans together as ‘‘archaic’’ Homo sapiens will no longer work. The picture is highly complex, and several taxa probably are needed to accommodate the fossils. Evolutionary relationships among these populations must be clarified, but pose some major problems. I will address only a subset of these topics pertaining mainly to earlier Middle Pleistocene hominids.

Comparative analysis of the trigonid crests patterns in Homo antecessor molars at the enamel and dentine surfaces

Loss of the subarcuate fossa and the phylogeny of Nacholapithecus