Differences between Neandertal and modern human infant and child growth models

Studying the emergence of distinctive human growth patterns is essential to understanding the evolution of our species. The large number of Neandertal fossils makes this species the best candidate for a comparative study of growth patterns in archaic and modern humans. Here, Neandertal height growth during infancy and early childhood is described using a mathematical model. Height growth velocities for individuals five years old or younger are modelled as age functions based on different estimates of height and age for a set of ten Neandertal infants and children. The estimated heights of each Neandertal individual are compared with those of two modern human populations based on longitudinal and cross-sectional data. The model highlights differences in growth velocity during infancy (from the age of five months onward). We find that statural growth in Neandertal infants is much slower than that seen in modern humans, Neandertal growth is similar to modern humans at birth, but decreases around the third or fourth month. The markedly slower growth rates of Neandertal infants may be attributable to ontogenetic constraints or to metabolic stress, and contribute to short achieved adult stature relative to modern humans.     

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.     

The estimation of adult stature from metacarpal bone length

Stature was measured (in cm) in 166 (120 male; 46 female) predominantly white adults (age range: 17–87 years). A radiograph of one hand of each subject was taken (for routine diagnostic purposes) and the inter-articular length of all five metacarpal bones was measured with a sliding caliper. These metacarpal lengths were then adjusted to compensate for enlargement during radiography. A significant correlation coefficient between stature and metacarpal length was observed in both sexes. Regression equations were computed from the length of each metacarpal, by which living stature may be fairly accurately estimated in the absence of any complete limb bones. The difference between our estimates and those obtained by more orthodox methods is usually less than 3%.     

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.     

Stature estimation from complete long bones in the Middle Pleistocene humans from the Sima de los Huesos, Sierra de Atapuerca (Spain)

Systematic excavations at the site of the Sima de los Huesos (SH) in the Sierra de Atapuerca (Burgos, Spain) have allowed us to reconstruct 27 complete long bones of the human species Homo heidelbergensis. The SH sample is used here, together with a sample of 39 complete Homo neanderthalensis long bones and 17 complete early Homo sapiens (Skhul/Qafzeh) long bones, to compare the stature of these three different human species. Stature is estimated for each bone using race- and sex-independent regression formulae, yielding an average stature for each bone within each taxon. The mean length of each long bone from SH is significantly greater (p < 0.05) than the corresponding mean values in the Neandertal sample. The stature has been calculated for male and female specimens separately, averaging both means to calculate a general mean. This general mean stature for the entire sample of long bones is 163.6 cm for the SH hominins, 160.6 cm for Neandertals and 177.4 cm for early modern humans. Despite some overlap in the ranges of variation, all mean values in the SH sample (whether considering isolated bones, the upper or lower limb, males or females or more complete individuals) are larger than those of Neandertals. Given the strong relationship between long bone length and stature, we conclude that SH hominins represent a slightly taller population or species than the Neandertals. However, compared with living European Mediterranean populations, neither the Sima de los Huesos hominins nor the Neandertals should be considered ‘short’ people. In fact, the average stature within the genus Homo seems to have changed little over the course of the last two million years, since the appearance of Homo ergaster in East Africa. It is only with the emergence of H. sapiens, whose earliest representatives were ‘very tall’, that a significant increase in stature can be documented.     

Relationships between lengths of long bones among recent Americans and Early Medieval Alamannic Germans

Relationships between lengths of long bones in early medieval Alamanns and in recent white Americans do not differ significantly. Lacking evidence of any differences between the contribution of trunk length to stature in the two samples, formulas for estimating stature based on relationships of bone lengths to stature in an American sample thus appear applicable to the Alamannic material.     

Human remains from Blombos Cave, South Africa: (1997-1998 excavations)

The Middle Stone Age (MSA) layers at Blombos Cave contain abundant bifacial Still Bay points, formal and ad hoc bone artefacts, and an intentionally incised bone piece. These artefacts add weight to arguments that some aspects of modern human behavior developed earlier in sub-Saharan Africa than elsewhere. Four human teeth were recovered from the MSA strata at Blombos during the 1997-1998 excavations. Two are heavily worn deciduous teeth, and two are incomplete permanent premolar crowns. The Blombos di(1)is comparatively large in relation to modern African homologues, falling within the lower part of the observed Neandertal range. The dm(1)and P(3)are comparable to modern teeth and smaller than most Neandertal crowns. The premolars preserve horizontal circum-cervical striae that suggest palliative toothpick use. The di(1)evinces labial scratches that resemble neither the "cutmarks" that have been observed on Neandertal incisors, nor the striae that have been recorded on modern human teeth.     

Body size prediction from juvenile skeletal remains

There are currently no methods for predicting body mass from juvenile skeletal remains and only a very limited number for predicting stature. In this study, stature and body mass prediction equations are generated for each year from 1 to 17 years of age using a subset of the Denver Growth Study sample, followed longitudinally (n = 20 individuals, 340 observations). Radiographic measurements of femoral distal metaphyseal and head breadth are used to predict body mass and long bone lengths are used to predict stature. In addition, pelvic bi-iliac breadth and long bone lengths are used to predict body mass in older adolescents. Relative prediction errors are equal to or smaller than those associated with similar adult estimation formulae. Body proportions change continuously throughout growth, necessitating age-specific formulae. Adult formulae overestimate stature and body mass in younger juveniles, but work well in 17-year-olds from the sample, indicating that in terms of body proportions they are representative of the general population. To illustrate use of the techniques, they are applied to the juvenile Homo erectus (ergaster) KNM-WT 15000 skeleton. New body mass and stature estimates for this specimen are similar to previous estimates derived using other methods. Body mass estimates range from 50 to 53 kg, and stature was probably slightly under 157 cm, although a precise stature estimate is difficult to determine due to differences in linear body proportions between KNM-WT 15000 and the Denver reference sample.     

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.     

Lower limb entheseal morphology in the Neandertal Krapina population (Croatia, 130,000 BP)

Although the Neandertal locomotor system has been shown to differ from Homo sapiens, characteristics of Neandertal entheses, the skeletal attachments for muscles, tendons, ligaments and joint capsules, have never been specifically investigated. Here, we analyse lower limb entheses of the Krapina Neandertal bones (Croatia, 130,000 BP) with the aim of determining how they compare with modern humans, using a standard developed by our research group for describing modern human entheseal variability. The entheses examined are those of the gluteus maximus, iliopsoas and vastus medialis on the femur, the quadriceps tendon on the patella, and soleus on the tibia. For the entheses showing a different morphological pattern from H. sapiens, we discuss the possibility of recognising genetic versus environmental causes. Our results indicate that only the gluteus maximus enthesis (the gluteal tuberosity), falls out of the modern human range of variation. It displays morphological features that could imply histological differences from modern humans, in particular the presence of fibrocartilage. In both H. sapiens and the Krapina Neandertals, the morphological pattern of this enthesis is the same in adult and immature femurs. These results can be interpreted in light of genetic differences between the two hominins. The possibility of functional adaptations to higher levels of mechanical load during life in the Neandertals seems less likely. The particular morphology and large dimensions of the Krapina enthesis, and perhaps its fibrocartilaginous nature, could have been selected for in association with other pelvic and lower limb characteristics, even if genetic drift cannot be ruled out.     

The Spy VI child: a newly discovered Neandertal infant

Spy cave (Jemeppe-sur-Sambre, Belgium) is reputed for the two adult Neandertal individuals discovered in situ in 1886. Recent reassessment of the Spy collections has allowed direct radiocarbon dating of these individuals. The sorting of all of the faunal collections has also led to the discovery of the remains of a Neandertal child, Spy VI. This individual is represented by two mandibular corpus fragments. The left fragment is the most complete and both sides preserve the mental foramen. Four deciduous teeth are associated with these mandibular remains: three incisors and one canine. The lower left canine (Spy 645a) conjoins with the corresponding alveolar socket in the left part of the mandible. Following extant standards, the developmental stage of the preserved teeth indicate an age at death of about one and a half years. In addition to performing a classical morphometric comparative study of the mandible and teeth, we have evaluated the dental tissue proportions using high-resolution microtomographic techniques. Our results show that Spy VI generally falls within the Neandertal range of variation. However, this specimen also exhibits particular traits, notably in the dental internal structural organization, which reveals that variation in the immature Neandertal variation is larger than what was variation currently represented by the available fossil record. These observations demonstrate the need for investigating the frequency and expression of immature Neandertal traits in fossil anterior teeth, as well as their temporal and geographic variation. Direct radiocarbon dating of the Spy VI specimen has been conducted in two different laboratories. The results of Spy VI confirm the age previously determined for the two adults, making the Spy Neandertal remains the youngest ever directly dated in northwest Europe.     

Stature and body mass estimation from skeletal remains in the European Holocene

Techniques that are currently available for estimating stature and body mass from European skeletal remains are all subject to various limitations. Here, we develop new prediction equations based on large skeletal samples representing much of the continent and temporal periods ranging from the Mesolithic to the 20th century. Anatomical reconstruction of stature is carried out for 501 individuals, and body mass is calculated from estimated stature and biiliac breadth in 1,145 individuals. These data are used to derive stature estimation formulae based on long bone lengths and body mass estimation formulae based on femoral head breadth. Prediction accuracy is superior to that of previously available methods. No systematic geographic or temporal variation in prediction errors is apparent, except in tibial estimation of stature, where northern and southern European formulae are necessary because of the presence of relatively longer tibiae in southern samples. Thus, these equations should bebroadly applicable to European Holocene skeletal samples.     

What molars contribute to an emerging understanding of lateral enamel formation in Neandertals vs. modern humans

Two hypotheses, based on previous work on Neandertal anterior and premolar teeth, are investigated here: (1) that estimated molar lateral enamel formation times in Neandertals are likely to fall within the range of modern human population variation, and (2) that perikymata (lateral enamel growth increments) are distributed across cervical and occlusal halves of the crown differently in Neandertals than they are in modern humans. To investigate these hypotheses, total perikymata numbers and the distribution of perikymata across deciles of crown height were compared for Neandertal, northern European, and southern African upper molar mesiobuccal (mb) cusps, lower molar mesiobuccal cusps, and the lower first molar distobuccal (db) cusp. Sample sizes range from five (Neandertal M(1)db) to 29 (southern African M(1)mb). Neandertal mean perikymata numbers were found to differ significantly from those of both modern human samples (with the Neandertal mean higher) only for the M(2)mb. Regression analysis suggests that, with the exception of the M(2)mb, the hypothesis of equivalence between Neandertal and modern human lateral enamel formation time cannot be rejected. For the M(2)mb, regression analysis strongly suggests that this cusp took longer to form in the Neandertal sample than it did in the southern African sample. Plots of perikymata numbers across deciles of crown height demonstrate that Neandertal perikymata are distributed more evenly across the cervical and occlusal halves of molar crowns than they are in the modern human samples. These results are integrated into a discussion of Neandertal and modern human lateral enamel formation across the dentition, with reference to issues of life history and enamel growth processes.     

La Ferrassie 6 and the development of Neandertal pubic morphology

Functional interpretations of the mediolateral elongation and superoinferior flattening of the superior pubic ramus of Neandertals require knowledge of its ontogeny. Metric comparisons between the La Ferrassie 6 Neandertal infant, aged 3-5 years, and a sample of modern infants reveal that the acetabulosymphyseal length of La Ferrassie 6, relative to femoral length and iliac breadth, falls at the limits of the range of variation of the modern infants, while the relative height of its superior pubic ramus is indistinguishable from that of the modern sample. It appears that acetabulosymphyseal elongation of the Neandertal pubis is a feature which is expressed quite early in ontogeny, well before puberty. Superoinferior flattening and ventral margin thinning of the superior ramus probably appear later in Neandertal ontogeny.     

Stature estimation in ancient Egyptians: a new technique based on anatomical reconstruction of stature

Trotter and Gleser's (Trotter and Gleser: Am J Phys Anthropol 10 (1952) 469-514; Trotter and Gleser: Am J Phys Anthropol 16 (1958) 79-123) long bone formulae for US Blacks or derivations thereof (Robins and Shute: Hum Evol 1 (1986) 313-324) have been previously used to estimate the stature of ancient Egyptians. However, limb length to stature proportions differ between human populations; consequently, the most accurate mathematical stature estimates will be obtained when the population being examined is as similar as possible in proportions to the population used to create the equations. The purpose of this study was to create new stature regression formulae based on direct reconstructions of stature in ancient Egyptians and assess their accuracy in comparison to other stature estimation methods. We also compare Egyptian body proportions to those of modern American Blacks and Whites. Living stature estimates were derived using a revised Fully anatomical method (Raxter et al.: Am J Phys Anthropol 130 (2006) 374-384). Long bone stature regression equations were then derived for each sex. Our results confirm that, although ancient Egyptians are closer in body proportion to modern American Blacks than they are to American Whites, proportions in Blacks and Egyptians are not identical. The newly generated Egyptian-based stature regression formulae have standard errors of estimate of 1.9-4.2 cm. All mean directional differences are less than 0.4% compared to anatomically estimated stature, while results using previous formulae are more variable, with mean directional biases varying between 0.2% and 1.1%, tibial and radial estimates being the most biased. There is no evidence for significant variation in proportions among temporal or social groupings; thus, the new formulae may be broadly applicable to ancient Egyptian remains.     

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.     

Comparison of the increase in body size between 1899 and 1970 in a specially selected group with that in the general population

Height and weight data for varsity football players from 1899 to 1970 were analyzed for evidence of a secular trend in such a specialized sample. Recent football teams ('61–'70) are, on the average, 2.6 inches (6.6 cm) taller and 35.3 pounds (16.05 kg) heavier than the teams at the turn of the century (1899–1910). The estimated trend over the 70 year span was 0.37 inches (0.94 cm) per decade for stature and 5.04 pounds (2.29 kg) per decade for weight. Unfortunately, it is not possible to partition these trends and obtain separate estimates for the “secular” effects and for those effects that might be attributed to “recruiting practices.” The observed trend for stature in football players corresponds with the upper limit of the estimated range for adult secular trend data for stature from Western European countries, and is greater than that reported for American young adult males both in college and in the general population.     

Last Interglacial Hominid and Associated Vertebrate Fossil Trackways in Coastal Eolianites,South Africa

Two Late Pleistocene hominid footprint sites are known in South Africa, one on the west coast (Langebaan) and the other on the southeast coast (Nahoon). Both trackways occur in calcareous eolianites and are dated to the Last Interglacial (～120 ka). The chief objective is to infer anatomical features of these early anatomically modern hominid footprint makers, about which little is known. At Nahoon, trackways of at least five species of vertebrates, including three hominid footprints, are preserved as casts. One footprint preserves excellent detail, appearing in all respects to be modern, but possibly with a deformity of the small toe. The impressions are shallow and suggest slight build. The stature of the footprint maker, as estimated from foot length (19.2 cm), is ～127 cm, considerably less than modern adult Khoi-San and was probably made by a juvenile. The step length is short relative to foot length, a consequence of walking uphill on a yielding substrate. The Langebaan trackway (preserved as natural impressions) comprises two intact prints and remnants of a third. Pronounced push up mounds flank the prints and preservation of toe impressions is poor. The foot length is 22.8 cm, indicating a stature of ～1.57 m. This falls within the range of modern adult Khoi-San, lending some support to the notion that Middle Stone Age people were of small stature. The depth of the prints and clumsy progression are suggestive of heavy build.     

Stature loss among an older United States population and its relation to bone mineral status

Age-related statural loss has been recorded but incompletely assessed in modern populations. In this study, data collected on stature during annual bone mineral assessments are analyzed for 1,024 Caucasian individuals from southern Arizona. Continued stabilization in reported maximum heights is seen in this population. With advancing age there is a gradual decrease in height apparently beginning in the mid-40s. Thereafter, there is a relatively rapid decrease in measured height. This contrasts to the much slower rates predicted from earlier populations (Trotter and Gleser: American Journal of Physical Anthropology 9:311-324, 1951). The rate of stature loss is associated with diminution of bone mineral density as well as with maximum height. Since there are suggestions of a secular trend toward greater reductions in bone mineral density, this study suggests there may be a secular trend toward an increase in statural loss with age.     

Stature estimation in prehistoric Native Americans of Ohio

In the present report we investigate stature estimation techniques in a sample of 64 (35 male, 29 female) prehistoric Native Americans from Ohio. Because living stature is unknown for these 64 individuals, we use Fully's (1956) anatomical method to provide the best estimates of living stature. In this method all osseous components of skeletal height are measured and soft tissue correction is added. Comparisons of regression equations commonly used for stature estimation in prehistoric Eastern Woodland Native American populations, but developed for East Asian and East Asian-derived populations (using lower extremity components), show that these commonly used equations consistently yield stature estimates 2 to 8 cm in excess of the best estimates from Fully's method. Based on the skeletal height measures of the 64 individuals in the present sample, we develop regression equations for the estimation of stature. These equations yield stature estimates virtually identical to estimates from Fully's method and may prove useful for stature reconstruction in other prehistoric Eastern Woodland Native American populations.