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.     

The Early Middle Palaeolithic lithic industry of Dederiyeh Cave,Northwest Syria

The Lower-to-Middle Paleolithic transition of the Levant has attracted much attention, particularly because the early Middle Paleolithic is the period when the earliest anatomically modern humans fossils known to date in Eurasia have been attested in that part of Asia . The associated lithic assemblages are a significant source of information for investigating the cultural landscape of this important transition. This paper presents a new dataset from the 2003–2009 excavations at Dederiyeh Cave, northwest of Syria. A techno-typological analysis of the lithic industry reveals a common practice of blade blank production, which corroborates the other known early Middle Paleolithic assemblages of the Levant. However, its strong emphasis on Levallois core reduction and sidescraper manufacturing is noteworthy. The significance of this finding deserves further research from multiple viewpoints, including the functional and spatio-temporal variability of hominin activities in this period. It will be also important to interpret the techno-typological diagnostics of the early Middle Paleolithic assemblage of Dederiyeh considering its geographic location at the northern end of the Levant, distant from the previously known sites in the central and southern Levant.     

Human skeletal remains from the cave of Hearths,Makapansgat, Northern Transvaal

A detailed study has been made of the oldest South African Upper Pleistocene hominid remains found in Acheulian context in a well-stratified sealed cave deposit, the Cave of Hearths, Makapansgat, Northern Transvaal. Possibly 55,000 years of age, the remains comprise a juvenile right mandibular body with teeth, and part of a right radius. The mandible is highly robust, markedly prognathous, has a slight to moderate bony chin, an appreciable planum alveolare, a low supraspinous foramen, large alveolar part with big tooth roots, parallel upper and lower borders, a superior transverse torus and poorly developed genial apophysis. The teeth are fairly large, narrow and elongate; M₂ is smaller than M₁; both molars have a +5 cusp pattern, and the first molar shows moderate taurodontism. There is good evidence that the jaw shows congenital lack of M₃: after the Chinese Lantian jaw, this is the second oldest hominid mandible and the first African fossil man with this feature. The radius has a relatively large head atop a disproportionately narrow neck; marked angulation of neck on shaft; and a strongly developed bicipital tubercle. The remains show a cluster of features which ally them with African Neandertaloids and earlier hominids of N.W. Africa. These geographically widespread African remains may represent a transitional population between H. erectus and H. sapiens neanderthalensis. This population has been called by Campbell, this author and others H. sapiens rhodesiensis (after the first-discovered specimen from Broken Hill): to this taxon the Cave of Hearths bones are tentatively assigned.     

Estimation of adult stature from the calcaneus and talus

Calcanei and tali of 100 skeletons in the Hamann–Todd Collection at the Cleveland Museum of Natural History were measured. The skeletons represented 50 males and 50 females distributed equally by race, i.e., whites and blacks. Linear-regression equations, with standard errors ranging from 4.09 to 6.11 cm, were derived from these measurements for the purpose of estimating stature. Two independent control samples, including one comprised of remains of American servicemen lost in World War II and the Korea and Vietnam wars, were tested with relatively accurate results. © 1995 Wiley-Liss, Inc.     

Estimation stature from X-rays of metacarpals in the Turkish population

Determination of stature is as important as the determination of sex and age when analyzing and identifying the remains of skeletons. Stature, in an approximate and widespread manner, is determined by the femur and tibia, i.e. those long bones that affect stature directly. However, when long bones are not available or when they are found in a very badly preserved condition that does not permit any estimation on stature, then other bones of the body can also be used for this purpose. The aim of this study is to determine stature with the help of metacarpals in the Turkish population. In this study, by using the X-ray films of metacarpal bones of 100 females and 100 males, regression equations have been set up for 5 metacarpal bones. The coefficients of correlation existing between the metacarpal bones and stature, together with the standard errors of these equations, have been intensively examined in this study. The results of studies conducted by other researchers such as Musgrave & Harneja (1978) and Meadows & Jantz (1992) have been compared with the results of our study. As a result of this comparison, the difference existing between them has been found to be significant according to the results of the t-test (p < 0.05, p < 0.01 and p < 0.001). The significance of such results proves that the general body characteristics and body proportions of populations are differing from each other and therefore specific regression equations for the different populations have to be set up.     

Virtual reconstruction of the Neandertal lower limbs with an estimation of hamstring muscle moment arms

A major problem of fossil hominid analysis is a lack of complete specimens. Many individual specimens have been damaged by the effects of diagenesis and excavation. Significant advances in the field of three dimensional image processing (3D) have enabled the creation of accurately scaled reconstructions of individual fossil bones using mirrored parts of the same fossil bone or human/fossil hominid equivalents. This study presents, for the first time, a method to reconstruct a 3D virtual model of the lower limb of the Neandertal using different bones from different fossil remains (Spy II, Neandertal 1 and Kebara 2) and integrating them into a single model of the Neandertal lower limb. A biomechanical analysis of the model was performed, including computer graphics visualization of the results, motion displacement graphs and muscle moment arms. The overall method has been implemented into an open-source customized software (lhpFusionBox) developed for the biomechanical study of the musculoskeletal system.     

Estimation of stature from long bones utilizing the line of organic correlation

Estimation of stature from skeletal measurements is of great interest in some studies, e.g. in forensic anthropology, where victims have to be identified. A problem occurring in practice is that the individual whose stature has to be assessed is in general from an unknown population. Alternatives to ordinary least squares regression are discussed. Application of available information about stature/long bone proportions leads to a general proposal called thethe weighted line of organic correlation, which is fitted to a wide range of populations. The effects of sex and race upon this line are practically negligible. These properties makes it suitable for use not only for forensic purposes, but also for the estimation of stature based on skeletons or skeletal populations from the past.     

Estimation of stature in children from second metacarpal measurements.

On the basis of 552 boys and 542 girls aged 6 to 20 years, this study examines the estimation of stature from dimensions and maturity of second metacarpals by means of linear regression equations. A combination of length and width measurements provided a more accurate estimation than each measurement individually. When taken alone, length produced a more accurate estimation than width. Sex and age factors are useful for the estimation of stature, though these variables are often unknown in the isolated bone. The samples are divided into immature and mature groups (according to skeletal maturity). Regardless of sex, stature could be estimated from the metacarpal length and width with a standard error of 4.19 cm by means of a multiple linear equation in the immature group. The mature group should be considered with adults for this purpose. Thus, taking into account their skeletal maturity, living stature could be practically estimated from the second metacarpal with significant degrees of accuracy in children.     

Extremely acidic, pendulous cave wall biofilms from the Frasassi cave system, Italy

The sulfide-rich Frasassi cave system hosts an aphotic, subsurface microbial ecosystem including extremely acidic (pH 0-1), viscous biofilms (snottites) hanging from the cave walls. We investigated the diversity and population structure of snottites from three locations in the cave system using full cycle rRNA methods and culturing. The snottites were composed primarily of bacteria related to Acidithiobacillus species. Other populations present in the snottites included Thermoplasmata group archaea, bacteria related to Sulfobacillus, Acidimicrobium, and the proposed bacterial lineage TM6, protists, and filamentous fungi. Based on fluorescence in situ hybridization population counts, Acidithiobacillus are key members of the snottite communities, accompanied in some cases by smaller numbers of archaea related to Ferroplasma and other Thermoplasmata. Diversity estimates show that the Frasassi snottites are among the lowest-diversity natural microbial communities known, with one to six prokaryotic phylotypes observed depending on the sample. This study represents the first in-depth molecular survey of cave snottite microbial diversity and population structure, and contributes to understanding of rapid limestone dissolution and cave formation by microbially mediated sulfuric acid speleogenesis.     

Technical note: a re-evaluation of stature estimation from skeletal length in the grave

Several methods for stature estimation have been proposed over the years. Among these methods is anatomical reconstruction, regression based on long bone lengths, and measuring skeletal vertex - talus length in the grave for individuals buried in a supine position. Recent studies have dealt with the applicability of skeletal length in the grave (Petersen: Int J Osteoarchaeol 15 (2005) 106-114) and anatomical reconstruction (Raxter et al.: Am J Phys Anthropol 130 (2006) 374-384). The results from the latter study calls into question the results of the former study. Therefore an investigation of the potential bias of using skeletal length in the grave as an estimate of living stature has been performed. Twenty Medieval Danish skeletons were measured both in situ and in the laboratory, and the anatomically reconstructed stature (Raxter et al.: Am J Phys Anthropol 130 (2006) 374-384) was compared with the skeletal length in the grave. The results show that 2.5 cm should be added to skeletal length in the grave in order to obtain an unbiased estimate ofliving stature.     

The short die young: the interrelationship between stature and longevity-evidence from skeletal remains

It has long been observed that tall people display longer life spans. The current data were employed to verify this association within the bioarchaeological context. To this end, stature and its association with age-at-death were analyzed in a pooled sample of 2,923 skeletons. Height was estimated from proxy indicators based on the maximum length of the humerus, radius, femur, and tibia. Stature estimation followed the procedure outlined by Pearson ([1899] Philos. Trans. R. Soc. Lond. [A] 192:169-244), incorporating minor modifications by R?sing ([ 1988] Handbuch der vergleichenden Biologie des Menschen; Stuttgart: Gustave Fischer, p 586-600). Individual age estimates were classified into three mutually exclusive age groups: 20-39 years (591 males, 667 females), 40-59 years (876 males, 499 females), and 60+ years (171 males, 119 females). The results document that both sexes display a statistically significant inverse relationship between adult height and age-at-death (males, P < 0.01; females, P < 0.05). Taking an epidemiological approach, the risk model implies that the estimated odds of survival beyond age 40 improve by approximately 16% for 1 SD in bone length. However, not all bones may be equally adept at displaying the association. The radius failed to support the positive association between stature and longevity, which may be indicative of a relatively greater contribution of environmental factor to radius length. Overall, the relationship between body height and longevity is not causal but coincidental: mitigated by diverse environmental factors such as nutrition, socioeconomic stressors, and disease load.     

A uniquely modern human pattern of endocranial development. Insights from a new cranial reconstruction of the Neandertal newborn from Mezmaiskaya

The globular braincase of modern humans is distinct from all fossil human species, including our closest extinct relatives, the Neandertals. Such adult shape differences must ultimately be rooted in different developmental patterns, but it is unclear at which point during ontogeny these group characteristics emerge.Here we compared internal shape changes of the braincase from birth to adulthood in Neandertals (N = 10), modern humans (N = 62), and chimpanzees (N = 62). Incomplete fossil specimens, including the two Neandertal newborns from Le Moustier 2 and Mezmaiskaya, were reconstructed using reference-based estimation methods. We used 3D geometric morphometrics to statistically compare shapes of virtual endocasts extracted from computed-tomographic scans. Throughout the analysis, we kept track of possible uncertainties due to the missing data values and small fossil sample sizes.We find that some aspects of endocranial development are shared by the three species. However, in the first year of life, modern humans depart from this presumably ancestral pattern of development. Newborn Neandertals and newborn modern humans have elongated braincases, and similar endocranial volumes. During a ‘globularization-phase’ modern human endocasts change to the globular shape that is characteristic for Homo sapiens. This phase of early development is unique to modern humans, and absent from chimpanzees and Neandertals.Our results support the notion that Neandertals and modern humans reach comparable adult brain sizes via different developmental pathways. The differences between these two human groups are most prominent directly after birth, a critical phase for cognitive development.     

Estimation of stature and body mass from the skeleton among coastal and mid-altitude Andean populations

Adult stature and body mass represent fundamental biological characteristics of individuals and populations, as they are relevant to a range of problems from assessing nutrition and health to longer term evolutionary processes. Stature and body mass estimation from skeletal dimensions are therefore key to addressing biological and social questions about past populations. Anatomical reconstruction provides the most direct proxy for living stature but is only suitable for well-preserved remains. Regression equations for estimating stature from bone lengths are therefore extremely useful, though it is well recognized that differences in body proportions limit the cross-application of equations between samples. Here, we assess the accuracy of published stature estimation equations from worldwide and New World groups applied to archaeological samples from the central Andean coast and highlands of South America. As no existing equations are clearly appropriate, new sample-specific regression equations are presented. Anatomical stature reconstruction is further complicated by artificial cranial modification (ACM) influencing cranial height in Andean samples, so this problem is investigated in the current sample. Although ACM has minimal impact here, the possibility should be explored in other samples before anatomical stature estimation is attempted. Recommendations are also made for estimating body mass from femoral head diameter. The mean of three previously published equations is shown to offer minimal bias and the most reliable estimate of body mass in the study samples.