Structure of bone in the skulls of Neanderthal fossils

Close inspection of surface bone in skulls of Neanderthal man reveals weathering cracks extensive enough in one specimen, La Chapelle-aux-Saints, to allow preliminary analysis of major patterns of orientation and to make inferences about functional relationships of structures. The fine structure of the bone of the brow ridges is very different from the rest of the skull in the two adults examined, having a peculiar vermiculate surface pattern. Weathering cracks do not appear in this region. This indicates that Neanderthal brow ridges are not closely related to normal mechanical forces such as chewing exertion. It may, however, give further support to theories of Neanderthal brow ridges as protection for the eyes. The localized structure of bone often differs from region to region, and offers new possibilities for the analysis of both contemporary and fossil forms.     

Mugharet el'Aliya: Affinities of an enigmatic north African Aterian maxillary fragment

Objectives

This study uses a virtual framework to examine the left maxillary fragment of the juvenile fossil from Mugharet el'Aliya, Morocco, found in association with an Aterian lithic industry. Previously, this fossil had been ascribed to modern humans or the Neanderthal lineage based on its “archaic”/“Neanderthal-like” features and apparent large size. Here, we conducted a novel 3D shape comparative analysis of the maxillary fragment to clarify its taxonomic affinities with regard to its size and ontogeny.

Materials and Methods

Eighty Computed Tomography and surface scans representing ontogenetic samples of Homo sapiens and Homo neanderthalensis were used to capture species-specific differences. The toolkit of geometric morphometrics in combination with surface registration and an elastic iterative closest point algorithm were used to create a dataset of meshes with an identical number of corresponding vertices for the maxillae. Multivariate statistics were applied to Procrustes superimposed coordinates derived from the vertices of this dataset.

Results

Our analysis showed affinities of the Mugharet el'Aliya individual with our H. sapiens sample, especially with a subadult individual from Qafzeh. No size-independent affinities with Neanderthals of comparable dental age could be identified.

Discussion

Our results add to the evidence connecting fossils from western Asia, especially Qafzeh and Skhul, and the North African Aterian. Furthermore, Mugharet el'Aliya adds to our knowledge of the ontogenetic development of adult morphology that is frequently used to characterize hominin groups, for example, Neanderthals and modern humans.     

A new discovery of Neanderthal settlements in Turkey: Sürmecik open-air campsite in Western Anatolia

Western Anatolia is the poorest region in terms of Turkey's Palaeolithic finds. In the past years, only a few Palaeolithic artefacts were known from the surface in the provinces of İzmir, Manisa, Kütahya and Afyonkarahisar in western Anatolia. After the fossil Homo erectus skull fragment was found in the travertine deposits in Kocabaş (Denizli) in 2002, the importance of the region more increased. After this important discovery, Dr. Kadriye Özçelik started a Palaeolithic survey in Denizli and found a large number of chipped stone tools from the Lower and Middle Palaeolithic periods. Nevertheless, the last important Palaeolithic discovery in the region was made in Sürmecik (Banaz-Uşak) in 2015. This is an open-air campsite belonging to the Middle Palaeolithic period. Here is also a mining area where a mining operation is conducted. The chipped stone artefacts of the Sürmecik Palaeolithic open-air campsite come from a clay layer between hematite and limonite deposits under a travertine layer of about 4.5–5 meters in thickness. Faunal remains represent mostly by equids species. All stages of Mousterian culture are clearly visible in this open-air campsite. Sürmecik is the richest middle Palaeolithic open-air campsite in Turkey. The 83,002 lithic pieces were collected in the excavations carried out in 2016 and 2017. It is thought that the lithic assemblage will exceed 100,000 with the ongoing studies. The group of bifacial leaf points in this collection is seen in Turkey for the first time. Four master thesis studies started on the lithic material of Sürmecik. It is planned to take some samples for dating analysis along with ongoing studies.     

Evaluating developmental shape changes in Homo antecessor subadult facial morphology

The fossil ATD6-69 from Atapuerca, Spain, dated to ca. 900 ka (thousands of years ago) has been suggested to mark the earliest appearance of modern human facial features. However, this specimen is a subadult and the interpretation of its morphology remains controversial, because it is unclear how developmental shape changes would affect the features that link ATD6-69 to modern humans. Here we analyze ATD6-69 in an evolutionary and developmental context. Our modern human sample comprises cross-sectional growth series from four populations. The fossil sample covers human specimens from the Pleistocene to the Upper Paleolithic, and includes several subadult Early Pleistocene humans and Neanderthals. We digitized landmarks and semilandmarks on surface and CT scans and analyzed the Procrustes shape coordinates using multivariate statistics. Ontogenetic allometric trajectories and developmental simulations were employed in order to identify growth patterns and to visualize potential adult shapes of ATD6-69. We show that facial differences between modern and archaic humans are not exclusively allometric. We find that while postnatal growth further accentuates the differences in facial features between Neanderthals and modern humans, those features that have been suggested to link ATD6-69's morphology to modern humans would not have been significantly altered in the course of subsequent development. In particular, the infraorbital depression on this specimen would have persisted into adulthood. However, many of the facial features that ATD6-69 shares with modern humans can be considered to be part of a generalized pattern of facial architecture. Our results present a complex picture regarding the polarity of facial features and demonstrate that some modern human-like facial morphology is intermittently present in Middle Pleistocene humans. We suggest that some of the facial features that characterize recent modern humans may have developed multiple times in human evolution.     

A comparison of antemortem tooth loss in human hunter‐gatherers and non‐human catarrhines: Implications for the identification of behavioral evolution in the human fossil record

Middle and Late Pleistocene fossil hominin specimens with severe antemortem tooth loss are often regarded as evidence for the precocious evolution of human‐like behaviors, such as conspecific care or cooking, in ancient hominin species. The goal of this project was to ask whether the theoretical association between antemortem tooth loss and uniquely human behaviors is supported empirically in a large skeletal sample of human hunter‐gatherers, chimpanzees, orangutans, and baboons. Binomial regression modeling in a Bayesian framework allows for the investigation of the effects of tooth class, genus, age, and sex on the likelihood of tooth loss. The results strongly suggest that modern humans experience more antemortem tooth loss than non‐human primates and identify age in years as an important predictor. Once age is accounted for, the difference between the humans and the closest non‐human genus (chimpanzees) is less pronounced; humans are still more likely on average to experience antemortem tooth loss though 95% uncertainty envelopes around the average prediction for each genus show some overlap. These analyses support theoretical links between antemortem tooth loss and modern human characteristics; humans' significantly longer life history and a positive correlation between age and antemortem tooth loss explain, in part, the reason why humans are more likely to experience tooth loss than non‐human primates, but the results do not exclude behavioral differences as a contributing factor. Am J Phys Anthropol 151:252–264, 2013. © 2013 Wiley Periodicals, Inc.     

Trinucleotide’s quadruplet symmetries and natural symmetry law of DNA creation ensuing Chargaff’s second parity rule

For almost 50 years the conclusive explanation of Chargaff’s second parity rule (CSPR), the equality of frequencies of nucleotides A=T and C=G or the equality of direct and reverse complement trinucleotides in the same DNA strand, has not been determined yet. Here, we relate CSPR to the interstrand mirror symmetry in 20 symbolic quadruplets of trinucleotides (direct, reverse complement, complement, and reverse) mapped to double-stranded genome. The symmetries of Q-box corresponding to quadruplets can be obtained as a consequence of Watson–Crick base pairing and CSPR together. Alternatively, assuming Natural symmetry law for DNA creation that each trinucleotide in one strand of DNA must simultaneously appear also in the opposite strand automatically leads to Q-box direct-reverse mirror symmetry which in conjunction with Watson–Crick base pairing generates CSPR. We demonstrate quadruplet’s symmetries in chromosomes of wide range of organisms, from Escherichia coli to Neanderthal and human genomes, introducing novel quadruplet-frequency histograms and 3D-diagrams with combined interstrand frequencies. These “landscapes” are mutually similar in all mammals, including extinct Neanderthals, and somewhat different in most of older species. In human chromosomes 1–12, and X, Y the “landscapes” are almost identical and slightly different in the remaining smaller and telocentric chromosomes. Quadruplet frequencies could provide a new robust tool for characterization and classification of genomes and their evolutionary trajectories.     

Size and placement of developing anterior teeth in immature Neanderthal mandibles from Dederiyeh Cave,Syria: Implications for emergence of the modern human chin

Evolutionary and functional significance of the human chin has long been explored from various perspectives including masticatory biomechanics, speech, and anterior tooth size. Recent ontogenetic studies have indicated that the spatial position of internally forming anterior teeth partially constrains adult mandibular symphyseal morphology. The present study therefore preliminarily examined the size and placement of developing anterior teeth in immature Neanderthal mandibles of Dederiyeh 1 and 2, compared with similarly‐aged modern humans (N = 16) and chimpanzees (N = 7) whose incisors are comparatively small and large among extant hominids, respectively. The Dederiyeh 1 mandible is described as slightly presenting a mental trigone and attendant mental fossa, whereas Dederiyeh 2 completely lacks such chin‐associated configurations. Results showed that, despite symphyseal size being within the modern human range, both Dederiyeh mandibles accommodated overall larger anterior dentition and displayed a remarkably wide bicanine space compared to those of modern humans. Dederiyeh 2 had comparatively thicker deciduous incisor roots and more enlarged permanent incisor crypts than Dederiyeh 1, but both Dederiyeh individuals exhibited a total dental size mostly intermediate between modern humans and chimpanzees. These findings potentially imply that the large deciduous/permanent incisors collectively distended the labial alveolar bone, obscuring an incipient mental trigone. It is therefore hypothesized that the appearance of chin‐associated features, particularly of the mental trigone and fossa, can be accounted for partly by developmental relationships between the sizes of the available mandibular space and anterior teeth. This hypothesis must be, however, further addressed with more referential samples in future studies. Am J Phys Anthropol 156:482–488, 2015. © 2014 Wiley Periodicals, Inc.     

Continuity and/or Discontinuity in the Pleistocene peopling of Europe?

Today, a number of European fossils are known which can be dated between 500,000 and 900,000 years ago. These remains provide evidence of an early human settlement of Europe, which apparently predates the emergence of Neanderthals. However, the taxonomic attribution of these fossils and their phylogenetic relationship to each other and to Neanderthals remains unclear. Evidence for a direct phylogenetic relationship with Neanderthals or a discontinuity is not yet conclusive. The task is complicated by the fact that the emergence of the Neanderthal population was not abrupt, but progressive. It is probable that the peopling of Europe during the entire Pleistocene was unique and presented from its very origins an “endemic” (a cul-de-sac) character, which may explain that the first traces of fossils in Europe illustrate particularities in comparison those from Africa and from Asia. Further paleontological discoveries will be needed to redefine the status of these features and to improve our understanding of human evolution in Europe.