Hominid footprints at Laetoli: facts and interpretations

The history of discovery and interpretation of primate footprints at the site of Laetoli in northern Tanzania is reviewed. An analysis of the geological context of these tracks is provided. The hominid tracks in Tuff 7 at Site G in the Garusi River Valley demonstrate bipedality at a mid-Pliocene datum. Comparison of these tracks and the Hadar hominid foot fossils by Tuttle has led him to conclude that Australopithecus afarensis did not make the Tanzanian prints and that a more derived form of hominid is therefore indicated at Laetoli. An alternative interpretation has been offered by Stern and Susman who posit a conforming "transitional morphology" in both the Tanzanian prints and the Ethiopian bones. The present examines both hypotheses and shows that neither is likely to be entirely correct. To illustrate this point, a reconstruction of the foot skeleton of a female A. afarensis is undertaken, and the results are compared to the Laetoli tracks. We conclude that A. afarensis represents the best candidate for the maker of the Laetoli hominid trails.     

Neanderthal axial and appendicular remains from Moula‐Guercy,Ardèche,France

Excavations carried out during the 1990s at Moula‐Guercy cave Ardèche, France, yielded 108 hominid specimens dating to 100–120 Ka. In this paper, we describe and compare the 39 axial and appendicular specimens not including hand and foot bones. Among these remains are a large adult femur, several clavicles, a likely antimeric pair of radial heads, and a nearly complete superior pubic ramus. Analyses of this material indicate a clear affinity with Neanderthals by the presence of large and robust muscle attachments, thick long bone cortices, a long pubic ramus, and a superoinferiorly flattened clavicle shaft. The recovered remains reveal the presence of a mature male, a smaller mature individual, possibly a reproductive age female, an immature individual of age 10–12, and a second immature individual of age 4. Future analyses on the Moula‐Guercy remains will illuminate ties to other known Neanderthal populations and contribute to the ongoing debate over the relative rate of Neanderthal metric growth. Am J Phys Anthropol 152:530–542, 2013. © 2013 Wiley Periodicals, Inc.     

The creation of specific hominid names: Gloria in excelsis deo? or ego? or praxis?

The recent recommendation that it is preferable to recognize too many rather than too few species in the fossil record has led to a growing proliferation of specific names. Single specimens are being referred to different species by different authors, and new species are being proposed based on the juxtaposition of specimens from different sites and time levels representing different anatomical parts. In part this may represent the continuity of the Medieval assertion that a multitude of species is a better demonstration of the goodness of a divinely created world than a multitude of individuals in a single species. This has apparently accompanied the resurgence of the Medieval faith that species relationship are best demonstrated by the application of hierarchical Aristotelean logic. On the other hand, the suspicion remains that the vanity of the namer is frequently involved in the creation of new nomina. In general, anthropologists do not exhibit the “wide experience” and consequent “sound judgment” that Darwin recommended as necessary for those giving specific names. If the same criteria used to assign specific fossil names were applied to modern Homo sapiens, the different regional human populations would have to be recognized as specifically distinct. In opposition to the recommendation that we should recognize ever more specific names, there should be a moratorium called and no new species names should be proposed at all. The continuation of patterns of trivial trait configurations associated with the various inhabited regions of the world clearly indicates genetic continuity through time but, unless it can be shown that there is no reproductive continuity between one region and another, these differences do not warrant taxonomic recognition. Major adaptive changes such as significant increases in relative brain size do warrant formal named recognition.     

Morphology and function of the lumbar spine of the Kebara 2 Neandertal

The morphology of the lumbar spine is crucial for upright posture and bipedal walking in hominids. The excellent preservation of the lumbar spine of Kebara 2 provides us a rare opportunity to observe a complete spine and explore its functionally relevant morphology. The lumbar spine of Kebara 2 is analyzed and compared with the lumbar spines of modern humans and late Pleistocene hominids. Although no size differences between the vertebral bodies and pedicles of Kebara 2 and modern humans are found, significant differences in the size and orientation of the transverse processes (L₁‐L₄), and the laminae (L₅, S₁) are demonstrated. The similarity in the size of the vertebral bodies and pedicles of Kebara 2 and modern humans suggests similarity in axial load transmission along the lumbar spine. The laterally projected (L₂‐L₄) and the cranially oriented (L₁, L₃) transverse processes of Kebara 2 show an advantage for lateral flexion of the lumbar spine compared with modern humans. The characteristic morphology of the lumbar spine of Kebara 2 might be related to the wide span of its pelvic bones. Am J Phys Anthropol 142:549–557, 2010. © 2010 Wiley‐Liss, Inc.     

Affinity,hominid evolution and Creationism. New computer methods weaken the Creationists' position

Using samples of skulls of early and modern hominids and modern pongids we compare the plausibility of Evolutionist and Creationist viewpoints. Multivariate methods are used to assess the corollary of Creationism that all fossil specimens which Evolutionists consider to be hominids are either apes or humans. We conclude that the results of this study cannot easily be accommodated within a Creationist framework, and, therefore, contribute substantial evidence for the Evolutionist viewpoint.     

Brief communication: Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli,Senegal: Conceptualization of “fire behavior” and the case for a chimpanzee model

The use and control of fire are uniquely human traits thought to have come about fairly late in the evolution of our lineage, and they are hypothesized to correlate with an increase in intellectual complexity. Given the relatively sophisticated cognitive abilities yet small brain size of living apes compared to humans and even early hominins, observations of wild chimpanzees' reactions to naturally occurring fire can help inform hypotheses about the likely responses of early hominins to fire. We use data on the behavior of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal during two encounters with wildfires to illuminate the similarities between great apes and humans regarding their reaction to fire. Chimpanzees' close relatedness to our lineage makes them phylogenetically relevant to the study of hominid evolution, and the open, hot and dry environment at Fongoli, similar to the savanna mosaic thought to characterize much of hominid evolution, makes these apes ecologically important as a living primate model as well. Chimpanzees at Fongoli calmly monitor wildfires and change their behavior in anticipation of the fire's movement. The ability to conceptualize the “behavior” of fire may be a synapomorphic trait characterizing the human‐chimpanzee clade. If the cognitive underpinnings of fire conceptualization are a primitive hominid trait, hypotheses concerning the origins of the control and use of fire may need revision. We argue that our findings exemplify the importance of using living chimpanzees as models for better understanding human evolution despite recently published suggestions to the contrary. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Neanderthal hand and foot remains from Moula‐Guercy,Ardèche,France

The hand and foot remains from Moula‐Guercy cave (Ardèche, France) comprise 24 specimens of Eemian age (ca. 120 ka). The specimens include primarily complete elements, which are rare among the Moula‐Guercy postcrania. The hand remains have several characteristic Neanderthal traits including a laterally facing (parasagittally oriented) second metacarpal‐capitate articulation, a short styloid process, a wide proximal articular surface on the third metacarpal, and absolutely expanded apical tuberosities on the distal hand phalanges relative to modern humans. The foot remains include several incomplete elements along with an antimeric pair of naviculars, a medial cuneiform and cuboid, and a single complete element from each of the distal segments (one each: metatarsal, proximal foot phalanx, intermediate foot phalanx, distal foot phalanx). Consistent among the specimens are relatively wide diaphyses for length in the metatarsals and phalanges and large and prominent muscle attachments, both consistent with previously published Neanderthal morphology. The hand and foot collection from Moula‐Guercy is an important dataset for future studies of Neanderthal functional morphology, dexterity, and behavior as it represents a previously undersampled time period for European Neanderthals. Am J Phys Anthropol 152:516–529, 2013. © 2013 Wiley Periodicals, Inc.     

Can revisionism,in evolutionary biology,help in formulating hypotheses about hominid evolution?

While evolutionary theory has been undergoing considerable revision for more than a decade scarcely any biological scientists are willing to resurrect the notion of acquired inheritance since it totally jndermines the concept of ancestor-descendant stability. Acquired inheritance is divisible into two components, soma to germ transfer to replicable information and directed or anticipatory mutation. Pure soma to germ transfer still allows for random events or natural selection as is evident from E. Steel’s proposal of the “somatic selection hypothesis”. Directed mutation is non-stochastic and self-referent. Recent bacterial research has claimed strong support for directed mutation but this phenomenon still would not be important for the small proportion of living taxa (including primates) who sequester their germlines early in ontogeny. There is a basic incompatibility between purposeful responses to final growth stages in complex metazoans and the need to permanently fix future growth into heritable programs. Symposium on Foundations for different approaches to the study of human evolution September 1–3, 1989, Liblice, Czechoslovakia, Czechoslovak Academy of Science     

Brief communication: Investigation of the semicircular canal variation in the Krapina Neandertals

Previous studies comparing bony labyrinth morphology in geographically‐dispersed samples of Neandertals and modern Homo sapiens (H. sapiens) showed that Neandertals generally have smaller semicircular canals than modern H. sapiens (Hublin et al., 1996 ; Spoor et al., 2003 ; Glantz et al., 2008 ). Here we analyze the morphology of a single group of Neandertal specimens from one locale, the Krapina site, to determine the intraspecific variation in Neandertal semicircular canal sizes. Dimensions of the semicircular canals were collected from computed tomography scans of nine temporal bones. With the rare exception, the dimensions of the semicircular canals in the Krapina sample are similar to those previously reported across a geographically‐dispersed sample of Neandertals, further supporting previous studies that suggest low levels of variation in the semicircular canals for Neandertals. Am J Phys Anthropol 154:302–306, 2014. © 2014 Wiley Periodicals, Inc.     

The evolution of brain size and intelligence in man

The brain size of hominids has increased approximately threefold during the evolution of the hominids fromAustralopithecus toHomo sapiens. It is proposed that the principal reason for this increase is that larger brains conferred greater intelligence, and greater intelligence conferred a selection advantage. A number of anthropologists have difficulty accepting this thesis because they believe that brain size is not associated with intelligence in man. Evidence is reviewed, and new evidence from two studies is presented, to show that brain size as measured by head size is positively correlated with intelligence as measured by intelligence tests. On two recent samples statistically significant correlations of .21 and .30 were obtained between estimates of brain size and IQ. It is considered that brain size is positively associated with intelligence in man and that this is the major reason for the increase in brain size of the hominids during the last 3.2 million years.     

Tooth chipping can reveal the diet and bite forces of fossil hominins

Mammalian tooth enamel is often chipped, providing clear evidence for localized contacts with large hard food objects. Here, we apply a simple fracture equation to estimate peak bite forces directly from chip size. Many fossil hominins exhibit antemortem chips on their posterior teeth, indicating their use of high bite forces. The inference that these species must have consumed large hard foods such as seeds is supported by the occurrence of similar chips among known modern-day seed predators such as orangutans and peccaries. The existence of tooth chip signatures also provides a way of identifying the consumption of rarely eaten foods that dental microwear and isotopic analysis are unlikely to detect.     

Early hominid enamel hypoplasia.

Enamel hypoplasia in the South African Plio-Pleistocene fossil hominid sample is examined. The Swartkrans hominids are shown to have a higher incidence of hypoplasia than the Sterkfontein hominids. Within the Swartkrans sample, individuals with hypoplasia of the first upper molar have lower-than-expected ages of death. Possible taphonomic explanations for these observations are discussed.     

Cortical bone distribution in the femoral neck of hominoids: Implications for the locomotion of Australopithecus afarensis

Contiguous high resolution computed tomography images were obtained at a 1.5 mm slice thickness perpendicular to the neck axis from the base of the femoral head to the trochanteric line in a sample of 10 specimens each of Homo sapiens, Pan troglodytes, and Gorilla gorilla, plus five specimens of Pan paniscus. Superior, inferior, anterior, and posterior cortical thicknesses were automatically measured directly from these digital images. Throughout the femoral neck H. sapiens displays thin superior cortical bone and inferior cortical bone that thickens distally. In marked contrast, cortical bone in the femoral neck of African apes is more uniformly thick in all directions, with even greater thickening of the superior cortical bone distally. Because the femoral neck acts as a cantilevered beam, its anchorage at the neck-shaft junction is subjected to the highest bending stresses and is the most biomechanically relevant region to inspect for response to strain. As evinced by A.L. 128-1, A.L. 211-1 and MAK-VP-1/1, Australopithecus afarensis is indistinguishable from H. sapiens, but markedly different from African apes in cortical bone distribution at the femoral neck-shaft junction. Cortical distribution in the African ape indicates much greater variation in loading conditions consistent with their more varied locomotor repertoire. Cortical distribution in hominids is a response to the more stereotypic loading pattern imposed by habitual bipedality, and thin superior cortex in A. afarensis confirms the absence of a significant arboreal component in its locomotor repertoire. Am J Phys Anthropol 104:117–131, 1997. © 1997 Wiley-Liss, Inc.     

Analysis of an early hominid ulna from the Omo basin,Ethiopia

The discovery (in 1971) of a nearly complete right ulna from the Shungura Formation of the Omo basin provides the opportunity to analyze the forelimb structure of the Australopithecus boisei form of early hominid. Results from multivariate morphometric analyses show that this bone is unique in shape among the extant hominoids although it is most similar to Pan and Homo. Despite its long slender shaft and large distal articular surface the bone's overall morphology is quite unlike Pongo.     

The mixed dentition and associated skull fragments of a juvenile fossil hominid from Sterkfontein,South Africa

In April–May 1983, the late A.R. Hughes and his field team recovered more than 40 bone fragments and teeth from a single solution pocket of the Sterkfontein Formation. After preparation and reconstruction by JMC, it was recognised that these fragments represent a single juvenile individual (Stw 151), consisting of more than 40 cranial and dental parts, with mixed dentition. It constitutes the most complete set of jaws and teeth of an early hominid child since the Taung child was recovered in 1924. In this paper, the morphological and metrical features of the individual teeth are described. The other associated skull fragments (right ramus of the mandible, left petrous bone, right glenoid region) are also described. Comparisons are made with other South (and East) African fossil hominids. The beautiful preservation simultaneously of most of the deciduous teeth and of the permanent teeth exposed in their crypts allows an accurate analysis of the developmental sequence. A report on the dental developmental status of this juvenile is presented. On the basis of the microanatomical study of the developing permanent teeth, the estimated age at death is 5.2–5.3 years. Reconstructions of the maxillary and mandibular arcades are also offered. The morphological and metrical features of Stw 151 raise the possibility that it may represent a hominid more derived towards an early Homo condition than the rest of the A. africanus sample from Member 4. Am J Phys Anthropol 106:425–465, 1998. © 1998 Wiley-Liss, Inc.     

Aimed throwing of stones by tufted capuchin monkeys (Cebus apella)

The purpose of this research was to examine aimed throwing of stones by tufted capuchin monkeys (Cebus apella). Three capuchins (two adults and one juvenile) threw stones at a stationary target located outside their home cages. The monkeys subsequently discriminated between stationary targets and threw stones at a moving target. Each subject exhibited a distinct manual and postural throwing preference. These results demonstrate that capuchins have throwing capabilities which are thought to have been associated with early hominid evolution.