Homo erectus brain sizes by subspecies

Homo erectus fossils can be divided into four zoogeographic zones that show different rates of endocranial expansion during the Pleistocene. When these are also grouped into three time levels, we find small increases from early to middle forms, and regularly greater increases from middle to late forms. These increases fit a regular pattern that also accomodates all archaic types, including Neandertals, as late subspecies ofH. erectus.     

The natural history of the helicoidal occlusal plane and its evolution in early Homo

In modern man the pitch of the occlusal plane may vary along the tooth-row. When anterior cheek-teeth show a plane sloping upward palatally, whilst that on posterior cheek-teeth slopes upward buccally, there results a twisted or helicoidal occlusal plane (Ackermann). Several hypotheses have been proposed for the structural basis of the helicoidal occlusal plane. Campbell's proposal ('25) has gained widest acceptance, namely that the helicoid results from anteroposterior differences in upper and lower alveolar arch width. In the early 1960s, while studying the Olduvai hominids assigned to Homo habilis, the author noted changing occlusal slopes along the tooth-row and a slight helicoid, although these featues had not been noted in other early hominids. Subsequently, Wallace showed a total absence of the helicoid from South African australopithecines, and its presence in Swartkrans Homo, SK 45 and SK 80. Recent studies confirm the presence of the helicoid in all available specimens of H. habilis, including Stw 53 found at Sterkfontein in 1976. Hence, this trait may distinguish between Australopithecus and early Homo. Measurements of the maxillary arch widths have shown that, whereas in Australopithecus arch widths increase to a maximum at M3, in early Homo maxillary arch widths are greatest at M2. The decline in posterior maxillary arch width is part of a general reduction of that region. Thus despite striking elongation of premolars and M1 in early Homo, M2 and M3 are mesiodistally abbreviated. It is hypothesized that the onset of posterior arch reduction, with the appearance of a helicoid, was a structural and functional concomitant of the transition from the presumed australopithecine ancestor to H. habilis.     

Upper pleistocene human remains from Vindija cave,Croatia, Yugoslavia

Human remains excavated from Vindija cave include a large although fragmentary sample of late Mousterian-associated specimens and a few additional individuals from the overlying early Upper Paleolithic levels. The Mousterian-associated sample is similar to European Neandertals from other regions. Compared with earlier Neandertals from south central Europe, this sample evinces evolutionary trends in the direction of Upper Paleolithic Europeans. Compared with the western European Neandertals, the same trends can be demonstrated, although the magnitude of difference is less, and there is a potential for confusing temporal with regional sources of variation. The early Upper Paleolithic-associated sample cannot be distinguished from the Mousterian-associated hominids. We believe that this site provides support for Hrdli?ka's “Neandertal phase” of human evolution, as it was originally applied in Europe.     

Étude taphonomique d’assemblages fauniques de sites à Homo erectus du dôme de Sangiran (Pléistocène moyen,Java central,Indonésie)

Since the sixties, the National Indonesian Center for Archaeological Research, in collaboration with the Gajah Mada University, organizes field excavations on open-air sites in the Sangiran dome, one of the most famous places of palaeoanthropological discoveries in Southeast Asia. That project led to the discovery of Homo erectus more or less fragmentary fossils, and to the collection of numerous mammal fossils in open-air localities such as Tanjung, Sendang Busik, Ngrejeng Plupuh, Grogol Plupuh and Bukuran. Most of the bone assemblages from these sites come from the volcanic-sedimentary Kabuh layers (Early Middle Pleistocene) deposited in a fluvial context. The herbivores dominate the assemblages. The best-represented species are large bovids like Bubalus palaeokerabau or Bibos palaesondaicus and smaller cervids like Axis lydekkeri. The carnivore are very rare, only a Pachycrocuta brevirostris in Bukuran. The taphonomical study of the collections, involving several common and also modern methods, is among the first carried out on Javanese sites. The high degree of fragmentation is attested by the dominance of splinters among the fossils. In most sites, teeth and member extremities (autopodial) prevail. Conservation and fragmentation of fossil bones is not the same at all sites. Water action, either chemical or mechanical, is predominant, regarding the origin and the modification of the assemblages. The climato-edaphic traces like oxides and concretions are well represented on the bone surface. Different methods were applied to study transportation and to document the sites contexts in the frame of the ancient riverine paleogeography. Carnivores are almost absent in the material and traces of their action are rare, only in Bukuran and Ngrejeng. The tools are rare, only a bola in Tanjung 82 and chalcedony flakes in Tanjung 63–64. Anthropic influence is only obvious at Ngebung 2, a site in the west part of the dome, supported by fossil observation and correlated to the occurrence of lithic artefacts. This site was excavated during the 1990’s by a French-Indonesian team and it is a site of comparison for our study. Several analytical methods could be applied for the first time on Pleistocene faunal assemblages from Java, for example, the study of the fragmentation, that of fissuration and the characterization of the fluviatile transport undergone by the fossils.     

Reconstructing cranial evolution in an extinct hominin

Homo erectus is the first hominin species with a truly cosmopolitan distribution and resembles recent humans in its broad spatial distribution. The microevolutionary events associated with dispersal and local adaptation may have produced similar population structure in both species. Understanding the evolutionary population dynamics of H. erectus has larger implications for the emergence of later Homo lineages in the Middle Pleistocene. Quantitative genetics models provide a means of interrogating aspects of long-standing H. erectus population history narratives. For the current study, cranial fossils were sorted into six major palaeodemes from sites across Africa and Asia spanning 1.8–0.1 Ma. Three-dimensional shape data from the occipital and frontal bones were used to compare intraspecific variation and test evolutionary hypotheses. Results indicate that H. erectus had higher individual and group variation than Homo sapiens, probably reflecting different levels of genetic diversity and population history in these spatially disperse species. This study also revealed distinct evolutionary histories for frontal and occipital bone shape in H. erectus, with a larger role for natural selection in the former. One scenario consistent with these findings is climate-driven facial adaptation in H. erectus, which is reflected in the frontal bone through integration with the orbits.     

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.     

Parallel episodes of phyletic dwarfism in callitrichid and cheirogaleid primates

The Callitrichidae are the smallest anthropoids, whereas the Cheirogaleidae include the smallest of all primates. Using species‐level analyses, we show that these are derived conditions; both neonatal and adult body mass decreased in a gradual, phyletic manner in parallel across callitrichids, and across cheirogaleids. We identify lineages with particularly rapid decreases and highlight the pygmy marmoset, Callithrix pygmaea, as a phenotypic outlier. The life‐history traits associated with body‐mass reduction in each clade suggest that the convergent evolution of small body size was achieved by changes in different ontogenetic stages. Body‐size reduction in callitrichids appears to be almost exclusively due to alterations in prenatal growth rate, whereas body‐size reduction in cheirogaleids may have been largely due to reduced duration of growth phases. Finally, we use these results to discuss some of the debates surrounding the evolution of Homo floresiensis and suggest potential parallels between the evolution of H. floresiensis and callitrichids.     

Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca,Burgos, Spain)

Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site.