RESUMEN
Here we analyze 1.07-0.99 million-year-old pelvic remains UA 173/405 from Buia, Eritrea. Based on size metrics, UA 173/405 is likely associated with an already described pubic symphysis (UA 466) found nearby. The morphology of UA 173/405 was quantitatively characterized using three-dimensional landmark-based morphometrics and linear data. The Buia specimen falls within the range of variation of modern humans for all metrics investigated, making it unlikely that the shared last common ancestor of Late Pleistocene Homo species would have had an australopith-like pelvis. The discovery of UA 173/405 adds to the increasing number of fossils suggesting that the postcranial morphology of Homo erectus s.l. was variable and, in some cases, nearly indistinguishable from modern human morphology. This Eritrean fossil demonstrates that modern human-like pelvic morphology may have had origins in the Early Pleistocene, potentially within later African H. erectus.
Asunto(s)
Fósiles/anatomía & histología , Hominidae/anatomía & histología , Pelvis/anatomía & histología , Sínfisis Pubiana/anatomía & histología , Animales , Eritrea , Femenino , MasculinoRESUMEN
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.
Asunto(s)
Hominidae/anatomía & histología , Cráneo/anatomía & histología , Animales , Antropología Física , EritreaRESUMEN
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 â¼1000 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.
Asunto(s)
Fósiles/anatomía & histología , Hominidae/anatomía & histología , Incisivo/anatomía & histología , Diente Molar/anatomía & histología , Animales , Eritrea , Fósiles/diagnóstico por imagen , Imagen por Resonancia Magnética , Microtomografía por Rayos XAsunto(s)
Cercopithecidae/clasificación , Fósiles , Hominidae/clasificación , Primates/clasificación , Cráneo/anatomía & histología , Animales , Evolución Biológica , Cercopithecidae/anatomía & histología , Eritrea , Sedimentos Geológicos , Hominidae/anatomía & histología , Humanos , Mamíferos/clasificación , Filogenia , Primates/anatomía & histologíaRESUMEN
We report on a late Oligocene proboscidean species from Eritrea, dated to 26.8 +/- 1.5 Mya. This "missing link" between early elephantiformes and Elephantimorpha is the oldest known nongomphothere proboscidean to probably display horizontal tooth displacement, typical of elephants [Elephantimorpha consists of Mammutida (mastodons) and Elephantida, and Elephantida includes gomphotheres, stegodons, and elephants]. Together with the newly discovered late Oligocene gomphotheres from Chilga, Ethiopia, the Eritrean taxon points to the importance of East Africa as a major area for the knowledge of the early evolution of Elephantimorpha before the faunal exchange between Eurasia and Africa.