Human taxonomic diversity in the pleistocene: Does Homo erectus represent multiple hominid species?

Recently, nomina such as “Homo heidelbergensis” and “H. ergaster” have been resurrected to refer to fossil hominids that are perceived to be specifically distinct from Homo sapiens and Homo erectus. This results in a later human fossil record that is nearly as speciose as that documenting the earlier history of the family Hominidae. However, it is agreed that there remains only one extant hominid species: H. sapiens. Has human taxonomic diversity been significantly pruned over the last few hundred millennia, or have the number of taxa been seriously overestimated? To answer this question, the following null hypothesis is tested: polytypism was established relatively early and the species H. erectus can accommodate all spatio-temporal variation from ca. 1.7 to 0.5 Ma. A disproof of this hypothesis would suggest that modern human polytypism is a very recent phenomenon and that speciation throughout the course of human evolution was the norm and not the exception. Cranial variation in a taxonomically mixed sample of fossil hominids, and in a modern human sample, is analyzed with regard to the variation present in the fossils attributed to H. erectus. The data are examined using both univariate (coefficient of variation) and multivariate (determinant) analyses. Employing randomization methodology to offset the small size and non-normal distribution of the fossil samples, the CV and determinant results reveal a pattern and degree of variation in H. erectus that most closely approximates that of the single species H. sapiens. It is therefore concluded that the null hypothesis cannot be rejected. © 1993 Wiley-Liss, Inc.     

Length estimate for KNM-ER 736, a hominid femur from the lower pleistocene of East Africa

Our knowledge concerning stature in earlyHomo is scanty. In this paper, based on comparison with the fossil femur KNM-ER 999, an estimate of 482 mm femur length is derived for KNM-ER 736, the latter dating from the Lower Pleistocene. From comparison with other fossil and modern femora, KNM-ER 736 appears to be the longest hominid femur so far recovered from a site of Early Pleistocene age. Moreover, the estimated femur length is higher than the published mean values of most modern populations. Provided that trunk and head proportions were not radically different from modernH. sapiens, the finding would suggest that a stature similar to that of modern man was already reached by East AfricanHomo as early as about 1.6 Myr before present.     

Position chronologique des sites de l’Homme moderne en Chine d’après la datation U-Th

The origin and evolution of modern Homo sapiens has been the subject of an intensive debate between exponents of two competing hypotheses, multiregional origins and “recent out of Africa”. This paper presents a synthesis of the chronological studies on seven hominid sites in China based on the U-series dating, five of them of intercalated speleothem calcites and other two of fossil materials. The results show that modern humans were present in China about 100 ka ago, much earlier than previously estimated, and that the so-called “temporal gap” of human presence in China between 40 and 100 ka is most probably nothing but an artifact caused by systematic errors of the dating methods. Further multidisciplinary studies on hominid sites in China may provide important evidence for resolving the hotly debated issues concerning the origin of modern humans.     

Fossil Humankind and Other Anthropoid Primates of China

More than 70 sites have yielded human fossils in China. They are attributed to Homo sapiens erectus and Homo sapiens sapiens. The earliest one is possibly about 1.7 Ma. A series of common morphological features, including shovel-shaped incisors and flatness of the face, characterize them. There is a morphological mosaic between H. s. erectus and H. s. sapiens in China. The existence of common features and the morphological mosaic suggest continuity of human evolution in China. That there are a few features which are more commonly seen in the Neanderthal lineage, occurring in a few Chinese fossil skulls, probably suggests gene flow between China and the West. Based on them, in 1998 I proposed an hypothesis—continuity with hybridization—for human evolution in China. The hypothesis is supported by paleolithic archeology, and it supports the multiregional evolution hypothesis of modern human origins. The anatomically modern humans of East Asia originated most probably in China. Although some nonhuman anthropoid primates of China—Gigantopithecus, Sivapithecus, Ramapithecus and Lufengpithecus—have been suggested as the direct ancestors of human beings, the discovery of more specimens and further studies do not support these suggestions. Therefore, it is most probable that the transition between apes and humans did not occur in China.     

A solution to the human paradox: fundamental ontogenies and heterochronies

Solving the human paradox means explaining how a genetic difference of a mere 1% can be consistent with 5 million years of anatomical transformation from great apes to present-dayHomo sapiens. The solution proposed here is that of the internal history of ontogenetic change. A concept of “fundamental ontogeny” is developed and deduced from comparison between living and fossil primates. The fossil human lineage can be summarized into five fundamental ontogenies corresponding to successive skull plans (bauplans) resulting from five major phases of craniofacial contraction: prosimians (adapiforms), monkey apes (propliopithecidae), great apes (dryopithecidae), australopithecines andHomo. The morphological areas defined by these skull plans include more-or-less numerous species. This concept leads to renewed debate about (i) the relationship between speciation and bauplans, and (ii) the mechanisms involved in the successive steps of cranio-facial contraction and the correlated morphological changes. It is suggested that, from great apes to modern man, numerous heterochronies (hypermorphosis, hypomorphosis and post-displacements) have occurred during ontogeny, allowing the acquisition of permanent bipedalism inAustralopithecus andHomo, the increased cranial capacity of primitive forms ofHomo, and the disappearance of simian characters associated with renewed increase in cranial capacity inH. sapiens.     

Variations and asymmetries in regional brain surface in the genus Homo

Paleoneurology is an important field of research within human evolution studies. Variations in size and shape of an endocast help to differentiate among fossil hominin species whereas endocranial asymmetries are related to behavior and cognitive function. Here we analyse variations of the surface of the frontal, parieto-temporal and occipital lobes among different species of Homo, including 39 fossil hominins, ten fossil anatomically modern Homo sapiens and 100 endocasts of extant modern humans. We also test for the possible asymmetries of these features in a large sample of modern humans and observe individual particularities in the fossil specimens.This study contributes important new information about the brain evolution in the genus Homo. Our results show that the general pattern of surface asymmetry for the different regional brain surfaces in fossil species of Homo does not seem to be different from the pattern described in a large sample of anatomically modern H. sapiens, i.e., the right hemisphere has a larger surface than the left, as do the right frontal, the right parieto-temporal and the left occipital lobes compared with the contra-lateral side. It also appears that Asian Homo erectus specimens are discriminated from all other samples of Homo, including African and Georgian specimens that are also sometimes included in that taxon. The Asian fossils show a significantly smaller relative size of the parietal and temporal lobes. Neandertals and anatomically modern H. sapiens, who share the largest endocranial volume of all hominins, show differences when considering the relative contribution of the frontal, parieto-temporal and occipital lobes. These results illustrate an original variation in the pattern of brain organization in hominins independent of variations in total size. The globularization of the brain and the enlargement of the parietal lobes could be considered derived features observed uniquely in anatomically modern H. sapiens.     

Les origines de l’art et les théories sur l’évolution humaine : le cas français

In recent years, we have witnessed an international debate about the question of the origins of art. On the one hand, some specialists have suggested that art appeared for the first time at the beginning of the Upper Paleolithic associated to the emergence of Homo sapiens sapiens. From this point of view, Paleolithic art as well as other hallmarks of behavioral modernity were exclusive to anatomically modern humans. On the other hand, some scholars have put into question the traditional paradigm concerning the origins of art and have suggested that artistic objects arose over a long period of time among different species, including Neanderthals. In order to contextualize this debate, we analyze in this article the history of the different interpretations and controversies concerning the question of the origins of art. Taking as reference the French case, we examine the connections between the different theories about art's origins suggested by Pleistocene art specialists during the last century and the dominant paradigms in human paleontology during the same period. Informed by one another, the question of the origins of art and that of human evolution seems to be inextricable linked.     

Human evolution at the Matuyama‐Brunhes boundary

The cranial morphology of fossil hominids between the end of the Early Pleistocene and the beginning of the Middle Pleistocene provides crucial evidence to understand the distribution in time and space of the genus Homo. This evidence is critical for evaluating the competing models regarding diversity within our genus. The debate focuses on two alternative hypotheses, one basically anagenetic and the other cladogenetic. The first suggests that morphological change is so diffused, slow, and steady that it is meaningless to apply species names to segments of a single lineage. The second is that the morphological variation observed in the fossil record can best be described as a number of distinct species that are not connected in a linear ancestor‐descendant sequence. Today much more fossil evidence is available than was in the past to test these alternative hypotheses, as well as intermediate variants. Special attention must be paid to Africa because this is the most probable continental homeland for both the origin of the genus Homo (around 2.5–2 Ma), 1 as well as the site, two million or so years later, of the emergence of the species H. sapiens. 2 However, the African fossil record is very poorly represented between 1 Ma and 600 ka. Europe furnishes recent discoveries in this time range around the Matuyama‐Brunhes chron boundary (780,000 years ago), a period for which, at present, we have no noteworthy fossil evidence in Africa or the Levant. Two penecontemporaneous sources of European fossil evidence, the Ceprano calvaria (Italy) 3 and the TD6 fossil assemblage of Atapuerca (Spain) 4 are thus of great interest for testing hypotheses about human evolution in the fundamental time span bracketed between the late Early and the Middle Pleistocene. This paper is based on a phenetic approach to cranial variation aimed at reviewing the Early‐to‐Middle Pleistocene trajectories of human evolution. The focus of the paper is on neither the origin nor the end of the story of the genus Homo, but rather its chronological and phylogenetic core. Elucidation of the evolutionary events that happened around 780 ka during the transition from the Early to Middle Pleistocene is one of the new frontiers for human paleontology, and is critical for understanding the processes that ultimately led to the origin of H. sapiens.     

The diploic venous system in Homo neanderthalensis and fossil Homo sapiens: A study using high-resolution computed tomography

Objectives

The diploic venous system has been hypothesized to be related to human brain evolution, though its evolutionary trajectory and physiological functions remain largely unclear. This study examines the characteristics of the diploic venous channels (DCs) in a selection of well-preserved Homo neanderthalensis and Upper Paleolithic Homo sapiens crania, searching for the differences between the two taxa and exploring the associations between brain anatomy and DCs.

Materials and Methods

Five H. neanderthalensis and four H. sapiens fossil specimens from Western Europe were analyzed. Based on Micro-CT scanning and 3D reconstruction, the distribution pattern and draining orifices of the DCs were inspected qualitatively. The size of the DCs was quantified by volume calculation, and the degree of complexity was quantified by fractal analyses.

Results

High-resolution data show the details of the DC structures not documented in previous studies. H. neanderthalensis and H. sapiens specimens share substantial similarities in the DCs. The noticeable differences between the two samples manifest in the connecting points surrounding the frontal sinuses, parietal foramina, and asterional area.

Discussion

This study provides a better understanding of the anatomy of the DCs in H. neanderthalensis and H. sapiens. The connection patterns of the DCs have potential utility in distinguishing between the two taxa and in the phylogenetic and taxonomic discussion of the Neandertal-like specimens with controversial taxonomic status.

     

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n = 127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M₁ and M₂ is small. In contrast, Aterian H. sapiens root surface areas peak at M₂. Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens.     

Neanderthal Skeletal Structure and the Place of Homo neanderthalensis in European Hominid Phylogeny

Although the debate rages on over whether the Neanderthals merit their own species status or should be viewed as an odd variant of Homo sapiens, recent evidence has accumulated that overwhelmingly supports the former interpretation. Among this evidence is a recent full-body skeletal reconstruction that not only highlights the extreme differences between the highly apomorphic H. sapiens and H. neanderthalensis in the construction of the thorax and pelvic girdle, but strongly suggests significant gait differences between the two species that add to the probability that the two kinds of hominid would not have recognized each other as breeding partners. This is hardly surprising since the two species possessed a relatively remote common ancestry, and it is indeed suggested here that Homo neanderthalensis was merely one species embedded within a diverse and endemic middle Pleistocene European hominid radiation. Clearly more than one lineage of hominids simultaneously occupied Europe during the middle Pleistocene.     

Allometry,merism, and tooth shape of the upper deciduous M2 and permanent M1

The aims of this study were to investigate the effect of allometry on the shape of dm² and M¹ crown outlines and to examine whether the trajectory and magnitude of scaling are shared between species. The sample included 160 recent Homo sapiens, 28 Upper Paleolithic H. sapiens, 10 early H. sapiens, and 33 H. neanderthalensis (Neandertal) individuals. Of these, 97 were dm²/M¹ pairs from the same individuals. A two‐block partial least squares analysis of paired individuals revealed a significant correlation in crown shape between dm² and M¹. A principal component analysis confirmed that Neandertal and H. sapiens dm² and M¹ shapes differ significantly and that this difference is primarily related to hypocone size and projection. Allometry accounted for a small but significant proportion of the total morphological variance. We found the magnitude of the allometric effect to be significantly stronger in Neandertals than in H. sapiens. Procrustes distances were significantly different between the two tooth classes in Neandertals, but not among H. sapiens groups. Nevertheless, we could not reject the null hypothesis that the two species share the same allometric trajectory. Although size clearly contributes to the unique shape of the Neandertal dm² and M¹, the largest H. sapiens teeth do not exhibit the most Neandertal‐like morphology. Hence, additional factors must contribute to the differences in dm² and M¹ crown shape between these two species. We suggest an investigation of the role of timing and rate of development on the shapes of the dm² and M¹ may provide further answers. Am J Phys Anthropol 154:104–114, 2014. © 2014 Wiley Periodicals, Inc.     

L’art Paléolithique est-il un « art » ?: Réflexions autour d’une question d’actualité

During the last years, an international debate about the concept of “Palaeolithic art” has taken place. On one hand, several specialists have critiqued the use of the concept of “art” in naming the images created by Homo sapiens during the Palaeolithic era. They claim that the use of this term implies the projection of a modern category to a world - that of prehistoric humans - which is completely different from our own. On the other hand, some archaeologists consider that the term “Palaeolithic art” does not imply an anachronistic interpretation of prehistoric representations. In presenting the historical context, which has made such a discussion possible, we consider the causes and effects of this controversy. Firstly, we analyze the traditional interpretation, which considered Palaeolithic images as “works of art”. Secondly, we examine the connections, which can be found between the debate about “Palaeolithic art” and certain polemics, which have arisen from the history of art and anthropological frameworks. Thirdly, we consider the arguments utilized by those who are for and those who are against the term “Palaeolithic art”. Finally, we emphasize the importance of this debate to better understand the categories and the concepts, which determine the scientific practice.     

“In Ways Unacademical”: The Reception of Carleton S. Coon's The Origin of Races

This paper examines the controversy surrounding anthropologist CarletonS. Coon's 1962 book, The Origin of Races. Coon maintained that thehuman sspecies was divided into five races before it had evolved into Homo sapiens and that the races evolved into sapiens at different times. Coon's thesis was used by segregationists in the United States as proof that African Americans were “junior” to white Americans and hence unfit for full participation in American society. The paper examines the interactions among Coon, segregationist Carleton Putnam, geneticist Theodosius Dobzhansky, and anthropologist Sherwood Washburn. The paper concludes that Coon actively aided the segregationist cause in violation of his own standards for scientific objectivity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cranial capacity in hominid evolution

We present an analysis of cranial capacity of 118 hominid crania available from the literature. The crania belong to both the genusAustralopithecus andHomo and provide a clear outline of hominid cranial evolution starting at more than 3 million years ago. Beginning withA. afarensis there is a clear increase in both absolute and relative brain size with every successive time period.H.s. neandertal has an absolutely and relatively smaller brain size (1412cc, E.Q.=5.6) than fossil modernH.s. sapiens (1487cc, E.Q.=5.9). Three evolutionary models of hominid brain evolution were tested: gradualism, punctuated equilibrium, and a mixed model using both gradualism and punctuated equilibrium. Both parametric and non-parametric analyses show a clear trend toward increasing brain size withH. erectus and a possible relationship within archaicH. sapiens. An evolutionary stasis in cranial capacity could not be refuted for all other taxa. Consequently, the mixed model appears to more fully explain hominid cranial capacity evolution. However, taxonomic decisions could directly compromise the possibility of testing the evolutionary mechanisms hypothesized to be operating in hominid brain expansion.     

The Homo sapiens ‘hemibun’: Its developmental pattern and the problem of homology

The occipital bun is widely considered a Neanderthal feature. Its homology to the ‘hemibun’ observed in some European Upper Palaeolithic anatomically modern humans is a current problem. This study quantitatively evaluates the degree of occipital plane convexity in African and Australian modern human crania to analyse a relationship between this feature and some neurocranial variables. Neanderthal and European Upper Palaeolithic Homo sapiens crania were included in the analysis as well. The results of this study indicated that there is a significant relationship between the degree of occipital plane convexity and the following two features in the examined crania of modern humans: the ratio of the maximum neurocranial height to the maximum width of the vault and the ratio of bregma–lambda chord to bregma–lambda arc. The results also revealed that some H. sapiens crania (modern and fossil) show the Neanderthal shape of the occipital plane and that the neurocranial height and shape of parietal midsagittal profile has an influence on occipital plane convexity in the hominins included in this study. This study suggests that the occurrence of the great convexity of the occipital plane in the Neanderthals and H. sapiens is a “by-product” of the relationship between the same neurocranial features and there is no convincing evidence that the Neanderthal occipital bun and the similar structure in H. sapiens develop during ontogeny in the same way.     

Reexamination of the immature hominid maxilla from Tangier,Morocco

Reexamination of the immature Upper Pleistocene hominid maxilla from Mugharet el-'Aliya (Tangier), Morocco is undertaken in light of new evidence on the growth and development of Upper Pleistocene hominids. Metric and qualitative comparisons were made with 17 immature Upper Pleistocene maxillae, and with a recent Homo sapiens sapiens sample. No unambiguous criteria for aligning the maxilla with Neandertals were found, although one character, the degree of maxillary flexion on the zygoma, strongly suggests that this child could be a representative of H. s. sapiens. The probable lack of a canine fossa in Mugharet el-'Aliya 1, the primary criterion used previously to align it with Neandertals, cannot be accurately extrapolated to its adult form from this juvenile. The present evidence suggests that it is inappropriate to refer to this fossil as “Neandertal-like” or as a North African “neandertaloid.” Thus, the Tangier maxilla should not be cited as evidence for the presence of Neandertal facial features in North Africa during the Upper Pleistocene. © 1993 Wiley-Liss, Inc.     

Homo erectus—who,when and where: A survey

The state of information bearing on Homo erectus as developed since about 1960 is surveyed, with the resulting effects on problems. Definitions of H. erectus still rest on the Far Eastern samples (Chou-k'ou-tien/Java), and thus relate to late Lower to middle Middle Pleistocene material. Numerous important individual finds, however, have expanded the total: extension of the early and very early Sangiran material; very early to later in Africa, and relatively late in Europe. Datings remain uncertain or controversial within broad limits, but with some important successes and revisions. Discussion by authors of problems concerns degree of divergence among H. erectus populations and rate of evolutionary change; both appear relatively slight, but the data are inadequate for much present judgment. The apparent zone of transition to more advanced morphology (H. sapiens, sensu lato) by the late Middle Pleistocene better reflects signs of regional divergence. Some writers—not all—believe that even the earliest European fossils known (e.g., Petralona) had already advanced to a H. sapiens basic level, with later change in the direction of Neanderthals. A separate African phylum, from OH 9, is also suggested; recent Chinese finds may provide a third different post-erectus population before the Upper Pleistocene. Taxonomic expression of all this gives some problems.     

The capitate of Australopithecus afarensis and A. africanus

The capitates of Australopithecus afarensis (AL 288-lw and AL 333–40) and A. africanus (TM 1526) have the identical combination of modern pongid, modern hominid, and unique characteristics. These traits include the combination of a length that is proximodistally shortened (Homo sapiens-like), a facet for the second metacarpal that is distolaterally facing (unique), the reduced styloid process on the third metacarpal (pongidlike), a dorsally placed trapezoid facet (pongidlike), mediolaterally constricted metacarpal III facet (pongidlike), a prominent palmar beak (pongidlike), a single elongated facet for the second metacarpal (H. sapiens-like), a waisted neck (pongidlike), and a reduced amount of “cupping” in the third metacarpal facet (H. sapiens-like). In overall shape the bones are more like H. sapiens than other extant hominids, although they are uniquely different. The two A. afarensis capitates provide no evidence that there are two postcranial morphotypes at Hadar. Available evidence shows that A. afarensis and A. africanus are strikingly similar postcranially. The morphological differences between the capitate of Australopithecus and H. sapiens may relate to the retention of climbing ability and an absence of certain grip capabilities in these early hominids.