Stratigraphic context and taxonomic assessment of the large cercopithecoid (Primates, Mammalia) from the late Early Pleistocene palaeoanthropological site of Buia (Eritrea)

First record of Theropithecus (Cercopithecidae) from the Republic of Djibouti

We describe here several specimens of the genus Theropithecus from the southern shore of Lake Assal in the Republic of Djibouti; they are the first record of the genus from this country. We assign them to a derived stage of T. oswaldi. This identification has implications for the age of the informal 'Formation 1' from this area, which should probably be assigned to the Middle Pleistocene. In addition, the presence of T. oswaldi close to the Bab el Mandeb Strait strongly suggests that the species followed this route to India, rather than a more northern one.

New cranium of the large cercopithecid primate Theropithecus oswaldi leakeyi (Hopwood, 1934) from the paleoanthropological site of Makuyuni, Tanzania

The Pleistocene hominin site of Makuyuni, near Lake Manyara, Tanzania, is known for fossils attributable to Homo and Acheulean artifacts (Ring et al., 2005; Kaiser et al., 2010; Frost et al., 2012). Here we describe the fossil primate material from the Manyara Beds, which includes the first nearly complete female cranium of Theropithecus oswaldi leakeyi and a proximal tibia from the same taxon. The cranium is dated to between 633 and 780 Ka and the tibia to the Pleistocene. The T. oswaldi lineage is one of the most important among Neogene mammals of Africa: it is both widespread and abundant. The size of the dentition, cranium, and tibia all confirm the previously recognized trend of increasing body size in this lineage and make their taxonomic assignments secure. The morphology of this specimen provides new insights into the evolution of this lineage through time, as well as its geographic variation and sexual dimorphism. The cranium also shows damage consistent with a mammalian carnivore, most likely a felid. The identification of this material as representing T. o. leakeyi agrees with the Middle Pleistocene age estimates for the MK4 locality in particular and the Manyara Beds in general.

The endocast of the one-million-year-old human cranium from Buia (UA 31), Danakil Eritrea

OBJECTIVES

The Homo erectus-like cranium from Buia (UA 31) was found in the Eritrean Danakil depression and dated to 1 million years. Its outer morphology displays archaic traits, as well as distinctive and derived characters. The present study provides the description and metric comparison of its endocranial anatomy.

MATERIALS AND METHODS

UA 31 was originally filled by a diffuse concretion. Following its removal and cleaning, the endocast (995 cc) was reconstructed after physical molding and digital scan. Its morphology is here compared with specimens belonging to different human taxa, taking into account endocranial metrics, cortical traits, and craniovascular features.

RESULTS

The endocast is long and narrow when compared to the H. erectus/ergaster hypodigm, although its proportions are compatible with the morphology displayed by all archaic and medium-brained human species. The occipital areas display a pronounced bulging, the cerebellum is located in a posterior position, and the middle meningeal vessels are more developed in the posterior regions. These features are common among specimens attributed to H. erectus s.l., particularly the Middle Pleistocene endocasts from Zhoukoudian. The parietal lobes are markedly bossed. This lateral bulging is associated with the lower parietal circumvolutions, as in other archaic specimens. This pronounced parietal curvature is apparently due to a narrow cranial base, more than to wider parietal areas.

CONCLUSIONS

The endocast of UA 31 shows a general plesiomorphic phenotype, with some individual features (e.g., dolichocephaly and rounded lower parietal areas) which confirm a remarkable degree of morphological variability within the H. erectus/ergaster hypodigm. Am J Phys Anthropol 160:458-468, 2016. © 2016 Wiley Periodicals, Inc.

The late Early Pleistocene human dental remains from Uadi Aalad and Mulhuli-Amo (Buia), Eritrean Danakil: macromorphology and microstructure

Fieldwork performed during the last 15 years in various Early Pleistocene East African sites has significantly enlarged the fossil record of Homo erectus sensu lato (s.l.). Additional evidence comes from the Danakil Depression of Eritrea, where over 200 late Early to early Middle Pleistocene sites have been identified within a ∼1000 m-thick sedimentary succession outcropping in the Dandiero Rift Basin, near Buia. Along with an adult cranium (UA 31), which displays a blend of H. erectus-like and derived morpho-architectural features and three pelvic remains, two isolated permanent incisors (UA 222 and UA 369) have also been recovered from the 1 Ma (millions of years ago) Homo-bearing outcrop of Uadi Aalad. Since 2010, our surveys have expanded to the nearby (4.7 km) site of Mulhuli-Amo (MA). This is a fossiliferous area that has been preliminarily surveyed because of its exceptional concentration of Acheulean stone tools. So far, the site has yielded 10 human remains, including the unworn crown of a lower permanent molar (MA 93). Using diverse analytical tools (including high resolution μCT and μMRI), we analysed the external and internal macromorphology and microstructure of the three specimens, and whenever possible compared the results with similar evidence from early Homo, H. erectus s.l., H. antecessor, H. heidelbergensis (from North Africa), Neanderthals and modern humans. We also assessed the UA 369 lower incisor from Uadi Aalad for root completion timing and showed that it compares well with data for root apex closure in modern human populations.