The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Michel Brunet - One of the best experts on this subject based on the ideXlab platform.
-
Subocclusal dental morphology of sahelanthropus tchadensis and the evolution of teeth in hominins.
American Journal of Physical Anthropology, 2014Co-Authors: Edouard-georges Emonet, Likius Andossa, Hassane Taïsso Mackaye, Michel BrunetAbstract:The evolution of the teeth in hominins is characterized by, among other characters, major changes in root morphology. However, little is known of the evolution from a plesiomorphic, ape-like root morphology to the crown hominin morphology. Here we present a study of the root morphology of the Miocene Chadian hominin Sahelanthropus tchadensis and its comparison to other hominins. The morphology of the whole lower dentition (I1 -M3 ) was investigated and described. The comparison with the species Ardipithecus kaddaba and Ardipithecus ramidus indicates a global homogeneity of root morphology in early hominins. This morphology, characterized notably by a reduction of the size and number of the roots of premolars, is a composite between an ape-like morphology and the later hominin morphology. Trends for root evolution in hominins are proposed, including the transition from a basal hominoid to extant Homo sapiens. This study also illustrates the low association between the evolution of tooth root morphology and the evolution of crowns in hominins.
-
The mammal assemblage of the Hominid site TM266 (Late Miocene, Chad Basin): ecological structure and paleoenvironmental implications
Naturwissenschaften, 2009Co-Authors: Emmanuel Fara, Patrick Vignaud, Hassane Taisso Mackaye, Michel BrunetAbstract:Characterizing the paleoenvironmental context of the first Hominids is a key issue for understanding their behavioral and morphological evolution. The present study aims at reconstructing the paleoenvironment of the TM266 vertebrate assemblage (Toros-Menalla, Northern Chad) that yielded the earliest known Hominid Sahelanthropus tchadensis (7 Ma). For the first time, a quantitative analysis is carried out on the fossil mammal assemblage associated with that Hominid. Two complementary approaches were applied: (1) the analysis of the relative abundances of taxa and their habitat preferences; and (2) the study of the distribution of taxa within three meaningful ecovariables: locomotion, feeding preferences, and body mass. The resulting taxonomic and paleoecological structures are used to reconstruct the diversity and the relative extent of the habitats in that part of northern Chad seven million years ago. The paleoenvironment was composed of open areas with dry and humid grasslands, prevailing over wooded habitats. Water was also widely available as freshwater bodies and certainly swamps. It appears that the high habitat diversity of the landscape is a common feature among paleoenvironments associated with early Hominids.
-
morphological affinities of the sahelanthropus tchadensis late miocene Hominid from chad cranium
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Franck Guy, David Pilbeam, Daniel E Lieberman, Marcia Ponce S De Leon, Andossa Likius, Hassane Taisso Mackaye, Patrick Vignaud, Christoph P E Zollikofer, Michel BrunetAbstract:The recent reconstruction of the Sahelanthropus tchadensis cranium (TM 266-01-60-1) provides an opportunity to examine in detail differences in cranial shape between this earliest-known Hominid, African apes, and other Hominid taxa. Here we compare the reconstruction of TM 266-01-60-1 with crania of African apes, humans, and several Pliocene Hominids. The results not only confirm that TM 266-01-60-1 is a Hominid but also reveal a unique mosaic of characters. The TM 266-01-60-1 reconstruction shares many primitive features with chimpanzees but overall is most similar to Australopithecus, particularly in the basicranium. However, TM 266-01-60-1 is distinctive in having the combination of a short subnasal region associated with a vertical upper face that projects substantially in front of the neurocranium. Further research is needed to determine the evolutionary relationships between Sahelanthropus and the known Miocene and Pliocene Hominids.
-
a new Hominid from the upper miocene of chad central africa
Nature, 2002Co-Authors: Michel Brunet, David Pilbeam, Franck Guy, Andossa Likius, Hassane Taisso Mackaye, Djimdoumalbaye Ahounta, Alain Beauvilain, Cecile BlondelAbstract:The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six Hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fauna suggest the fossils are between 6 and 7 million years old. The fossils display a unique mosaic of primitive and derived characters, and constitute a new genus and species of Hominid. The distance from the Rift Valley, and the great antiquity of the fossils, suggest that the earliest members of the Hominid clade were more widely distributed than has been thought, and that the divergence between the human and chimpanzee lineages was earlier than indicated by most molecular studies. From their initial description in 1925 1 until 1995, Hominids from the Pliocene (5.3‐1.6 million years, Myr) and late Upper Miocene (,7.5‐5.3 Myr) were known only from southern and eastern Africa. This distribution led some authors to postulate an East African origin for the Hominid clade (where the term ‘Hominid’ refers to any member of that group more closely related to extant humans than to
Tim D. White - One of the best experts on this subject based on the ideXlab platform.
-
Hominid butchers and biting crocodiles in the african plio pleistocene
Proceedings of the National Academy of Sciences of the United States of America, 2017Co-Authors: Yonatan Sahle, Sireen El Zaatari, Tim D. WhiteAbstract:Abstract Zooarchaeologists have long relied on linear traces and pits found on the surfaces of ancient bones to infer ancient Hominid behaviors such as slicing, chopping, and percussive actions during butchery of mammal carcasses. However, such claims about Plio–Pleistocene Hominids rely mostly on very small assemblages of bony remains. Furthermore, recent experiments on trampling animals and biting crocodiles have shown each to be capable of producing mimics of such marks. This equifinality—the creation of similar products by different processes—makes deciphering early archaeological bone assemblages difficult. Bone modifications among Ethiopian Plio–Pleistocene Hominid and faunal remains at Asa Issie, Maka, Hadar, and Bouri were reassessed in light of these findings. The results show that crocodiles were important modifiers of these bone assemblages. The relative roles of Hominids, mammalian carnivores, and crocodiles in the formation of Oldowan zooarchaeological assemblages will only be accurately revealed by better bounding equifinality. Critical analysis within a consilience-based approach is identified as the pathway forward. More experimental studies and increased archaeological fieldwork aimed at generating adequate samples are now required.
-
response to comment on the paleobiology and classification of ardipithecus ramidus
Science, 2010Co-Authors: Tim D. White, Gen Suwa, Owen C LovejoyAbstract:We assigned Ardipithecus to the Hominidae based on numerous dental, cranial, and postcranial characters. Sarmiento argues that these characters are not exclusive to Hominids, contending that Ardipithecus is too old to be cladistically Hominid. His alternative phylogeny, however, is unlikely because it requires tortuous, nonparsimonious evolutionary pathways.
-
ardipithecus ramidus and the paleobiology of early Hominids
Science, 2009Co-Authors: Tim D. White, Yohannes Haileselassie, Owen C Lovejoy, Gen Suwa, Berhane Asfaw, Yonas Beyene, Giday WoldegabrielAbstract:Hominid fossils predating the emergence of Australopithecus have been sparse and fragmentary. The evolution of our lineage after the last common ancestor we shared with chimpanzees has therefore remained unclear. Ardipithecus ramidus , recovered in ecologically and temporally resolved contexts in Ethiopia’s Afar Rift, now illuminates earlier Hominid paleobiology and aspects of extant African ape evolution. More than 110 specimens recovered from 4.4-million-year-old sediments include a partial skeleton with much of the skull, hands, feet, limbs, and pelvis. This Hominid combined arboreal palmigrade clambering and careful climbing with a form of terrestrial bipedality more primitive than that of Australopithecus . Ar. ramidus had a reduced canine/premolar complex and a little-derived cranial morphology and consumed a predominantly C 3 plant–based diet (plants using the C 3 photosynthetic pathway). Its ecological habitat appears to have been largely woodland-focused. Ar. ramidus lacks any characters typical of suspension, vertical climbing, or knuckle-walking. Ar. ramidus indicates that despite the genetic similarities of living humans and chimpanzees, the ancestor we last shared probably differed substantially from any extant African ape. Hominids and extant African apes have each become highly specialized through very different evolutionary pathways. This evidence also illuminates the origins of orthogrady, bipedality, ecology, diet, and social behavior in earliest Hominidae and helps to define the basal Hominid adaptation, thereby accentuating the derived nature of Australopithecus .
-
Hominid cranial remains from upper pleistocene deposits at aduma middle awash ethiopia
American Journal of Physical Anthropology, 2004Co-Authors: Yohannes Haileselassie, Berhane Asfaw, Tim D. WhiteAbstract:The Upper Pleistocene localities of Aduma and Bouri have yielded Hominid fossils and exten- sive Middle Stone Age (MSA) archaeological assemblages. The vertebrate fossils recovered include parts of four hom- inid crania from Aduma and a complete right parietal from Bouri. Archaeological associations and radiometric techniques suggest an Upper Pleistocene age for these Hominids. The more complete cranium from Aduma (ADU-VP-1/3) comprises most of the parietals, the occipi- tal, and part of the frontal. This cranium is compared to late Middle and Upper Pleistocene Hominid crania from Africa and the Middle East. The Aduma cranium shows a mosaic of cranial features shared with "premodern" and anatomically modern Homo sapiens. However, the poste- rior and lateral cranial dimensions, and most of its anat- omy, are centered among modern humans and resemble specimens from Omo, Skhul, and Qafzeh. As a result, the Aduma and Bouri Upper Pleistocene Hominids are as- signed to anatomically modern Homo sapiens. Am J Phys
-
pleistocene homo sapiens from middle awash ethiopia
Nature, 2003Co-Authors: Tim D. White, Gen Suwa, Berhane Asfaw, David Degusta, Henry Gilbert, Gary D Richards, Clark F HowellAbstract:The origin of anatomically modern Homo sapiens and the fate of Neanderthals have been fundamental questions in human evolutionary studies for over a century1,2,3,4. A key barrier to the resolution of these questions has been the lack of substantial and accurately dated African Hominid fossils from between 100,000 and 300,000 years ago5. Here we describe fossilized Hominid crania from Herto, Middle Awash, Ethiopia, that fill this gap and provide crucial evidence on the location, timing and contextual circumstances of the emergence of Homo sapiens. Radioisotopically dated to between 160,000 and 154,000 years ago6, these new fossils predate classic Neanderthals and lack their derived features. The Herto Hominids are morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans. They therefore represent the probable immediate ancestors of anatomically modern humans. Their anatomy and antiquity constitute strong evidence of modern-human emergence in Africa.
Travis Rayne Pickering - One of the best experts on this subject based on the ideXlab platform.
-
testing the shift in the balance of power hypothesis at swartkrans south africa Hominid cave use and subsistence behavior in the early pleistocene
Journal of Anthropological Archaeology, 2008Co-Authors: Manuel Dominguezrodrigo, Travis Rayne Pickering, Charles P Egeland, C K Brain, Amy G SchnellAbstract:Abstract C.K. Brain documented two interesting patterns in the Pleistocene faunas of Swartkrans Cave, South Africa: (1) The earliest depositional units, Members 1 and 2, preserve high numbers of Hominid fossils, while the numbers drop sharply in the more recent Member 3. (2) Burned bone specimens, which seem to have been altered in fires tended by Hominids, appear for the first time in Member 3. It was suggested that mastery of fire provided a “shift in the balance of power”, allowing Hominids to carry out activities in the cave for the first time unmolested by predators. A lack of butchered bones in Members 1 and 2 and their presence in Member 3 provided support for the hypothesis. However, we have now identified butchered bones in all three units. Further, our findings reveal a lack of variability in butchery patterns through time at Swartkrans; in all cases Hominids appear to have been proficient carcass foragers. The real “shift” at Swartkrans does not appear to be one of eventual Hominid dominance over carnivores, but rather one of a predominance of leopards at Swartkrans in Member 1 times to the alternating presence of leopards and hyenas in Members 2 and 3. Consistent leopard presence in Member 1 seems to have discouraged Hominid activity in the vicinity of the cave. In contrast, by the time Members 2 and 3 were forming Hominids may have temporarily used the cave, taking advantage of those periods of carnivore absence.
-
the contribution of limb bone fracture patterns to reconstructing early Hominid behaviour at swartkrans cave south africa archaeological application of a new analytical method
International Journal of Osteoarchaeology, 2005Co-Authors: Travis Rayne Pickering, Manuel Dominguezrodrigo, Charles P Egeland, C K BrainAbstract:Recently, Alcantara Garcia et al. (in press) presented a new method and criteria for distinguishing between fractures imparted by Hominid hammerstone percussion and carnivores chewing on ‘green’ limb bones of ungulates. The method uses a combination of fracture plane and fracture angle data that are useful for elucidating the relative role of Hominids in the accumulation of prehistoric archaeofaunas, especially when employed in concert with other classes of taphonomic data. We briefly summarise the method and apply it to the ungulate limb bone subassemblage from Swartkrans Member 3, a c. 1.0 million year old site from South Africa that preserves Early Stone Age lithic artefacts, Hominid fossils, and an abundant mammalian fauna with cutmarked, hammerstone-percussed and burned bone specimens. Results of the fracture pattern analysis corroborate indications from other lines of taphonomic data that there was minimal carnivore–Hominid interdependence in the formation of the fauna, and that carnivores were probably responsible for the majority of the bone collection in Member 3. However, we also document a significant Hominid influence on assemblage formation, a finding that expands and refines our understanding of large animal carcass foraging by Hominids in southern Africa during the early Pleistocene. Copyright © 2004 John Wiley & Sons, Ltd.
-
cutmarked bones from pliocene archaeological sites at gona afar ethiopia implications for the function of the world s oldest stone tools
Journal of Human Evolution, 2005Co-Authors: Manuel Dominguezrodrigo, Travis Rayne Pickering, Sileshi Semaw, Michael J. RogersAbstract:Abstract Newly recorded archaeological sites at Gona (Afar, Ethiopia) preserve both stone tools and faunal remains. These sites have also yielded the largest sample of cutmarked bones known from the time interval 2.58–2.1 million years ago (Ma). Most of the cutmarks on the Gona fauna possess obvious macroscopic (e.g., deep V-shaped cross-sections) and microscopic (e.g., internal microstriations, Herzian cones, shoulder effects) features that allow us to identify them confidently as instances of stone tool-imparted damage caused by Hominid butchery. In addition, preliminary observations of the anatomical placement of cutmarks on several of the recovered bone specimens suggest that Gona Hominids may have eviscerated carcasses and defleshed the fully muscled upper and intermediate limb bones of ungulates—activities that further suggest that Late Pliocene Hominids may have gained early access to large mammal carcasses. These observations support the hypothesis that the earliest stone artifacts functioned primarily as butchery tools and also imply that hunting and/or aggressive scavenging of large ungulate carcasses may have been part of the behavioral repertoire of Hominids by c . 2.5 Ma, although a larger sample of cutmarked bone specimens is necessary to support the latter inference.
Manuel Dominguezrodrigo - One of the best experts on this subject based on the ideXlab platform.
-
testing the shift in the balance of power hypothesis at swartkrans south africa Hominid cave use and subsistence behavior in the early pleistocene
Journal of Anthropological Archaeology, 2008Co-Authors: Manuel Dominguezrodrigo, Travis Rayne Pickering, Charles P Egeland, C K Brain, Amy G SchnellAbstract:Abstract C.K. Brain documented two interesting patterns in the Pleistocene faunas of Swartkrans Cave, South Africa: (1) The earliest depositional units, Members 1 and 2, preserve high numbers of Hominid fossils, while the numbers drop sharply in the more recent Member 3. (2) Burned bone specimens, which seem to have been altered in fires tended by Hominids, appear for the first time in Member 3. It was suggested that mastery of fire provided a “shift in the balance of power”, allowing Hominids to carry out activities in the cave for the first time unmolested by predators. A lack of butchered bones in Members 1 and 2 and their presence in Member 3 provided support for the hypothesis. However, we have now identified butchered bones in all three units. Further, our findings reveal a lack of variability in butchery patterns through time at Swartkrans; in all cases Hominids appear to have been proficient carcass foragers. The real “shift” at Swartkrans does not appear to be one of eventual Hominid dominance over carnivores, but rather one of a predominance of leopards at Swartkrans in Member 1 times to the alternating presence of leopards and hyenas in Members 2 and 3. Consistent leopard presence in Member 1 seems to have discouraged Hominid activity in the vicinity of the cave. In contrast, by the time Members 2 and 3 were forming Hominids may have temporarily used the cave, taking advantage of those periods of carnivore absence.
-
new estimates of tooth mark and percussion mark frequencies at the flk zinj site the carnivore Hominid carnivore hypothesis falsified
Journal of Human Evolution, 2006Co-Authors: Manuel Dominguezrodrigo, R BarbaAbstract:Abstract Traditional interpretations of Hominid carcass acquisition strategies revolve around the debate over whether early Hominids hunted or scavenged. A popular version of the scavenging scenario is the carnivore-Hominid-carnivore hypothesis, which argues that Hominids acquired animal resources primarily through passive opportunistic scavenging from felid-defleshed carcasses. Its main empirical support comes from the analysis of tooth mark frequency and distribution at the FLK Zinj site reported by Blumenschine (Blumenschine, 1995, J. Hum. Evol. 29, 21–51), in which it was shown that long bone mid-shafts exhibited a high frequency of tooth marks, only explainable if felids had preceded Hominids in carcass defleshing. The present work shows that previous estimates of tooth marks on the FLK Zinj assemblage were artificially high, since natural biochemical marks were mistaken for tooth marks. Revised estimates are similar to those obtained in experiments in which hyenas intervene after humans in bone modification. Furthermore, analyses of percussion marks, notches, and breakage patterns provide data which are best interpreted as the results of Hominid activity (hammerstone percussion and marrow extraction), based on experimentally-derived referential frameworks. These multiple lines of evidence support previous analyses of cut marks and their anatomical distribution; all indicate that Hominids had early access to fleshed carcasses that were transported, processed, and accumulated at the FLK Zinj site.
-
the contribution of limb bone fracture patterns to reconstructing early Hominid behaviour at swartkrans cave south africa archaeological application of a new analytical method
International Journal of Osteoarchaeology, 2005Co-Authors: Travis Rayne Pickering, Manuel Dominguezrodrigo, Charles P Egeland, C K BrainAbstract:Recently, Alcantara Garcia et al. (in press) presented a new method and criteria for distinguishing between fractures imparted by Hominid hammerstone percussion and carnivores chewing on ‘green’ limb bones of ungulates. The method uses a combination of fracture plane and fracture angle data that are useful for elucidating the relative role of Hominids in the accumulation of prehistoric archaeofaunas, especially when employed in concert with other classes of taphonomic data. We briefly summarise the method and apply it to the ungulate limb bone subassemblage from Swartkrans Member 3, a c. 1.0 million year old site from South Africa that preserves Early Stone Age lithic artefacts, Hominid fossils, and an abundant mammalian fauna with cutmarked, hammerstone-percussed and burned bone specimens. Results of the fracture pattern analysis corroborate indications from other lines of taphonomic data that there was minimal carnivore–Hominid interdependence in the formation of the fauna, and that carnivores were probably responsible for the majority of the bone collection in Member 3. However, we also document a significant Hominid influence on assemblage formation, a finding that expands and refines our understanding of large animal carcass foraging by Hominids in southern Africa during the early Pleistocene. Copyright © 2004 John Wiley & Sons, Ltd.
-
cutmarked bones from pliocene archaeological sites at gona afar ethiopia implications for the function of the world s oldest stone tools
Journal of Human Evolution, 2005Co-Authors: Manuel Dominguezrodrigo, Travis Rayne Pickering, Sileshi Semaw, Michael J. RogersAbstract:Abstract Newly recorded archaeological sites at Gona (Afar, Ethiopia) preserve both stone tools and faunal remains. These sites have also yielded the largest sample of cutmarked bones known from the time interval 2.58–2.1 million years ago (Ma). Most of the cutmarks on the Gona fauna possess obvious macroscopic (e.g., deep V-shaped cross-sections) and microscopic (e.g., internal microstriations, Herzian cones, shoulder effects) features that allow us to identify them confidently as instances of stone tool-imparted damage caused by Hominid butchery. In addition, preliminary observations of the anatomical placement of cutmarks on several of the recovered bone specimens suggest that Gona Hominids may have eviscerated carcasses and defleshed the fully muscled upper and intermediate limb bones of ungulates—activities that further suggest that Late Pliocene Hominids may have gained early access to large mammal carcasses. These observations support the hypothesis that the earliest stone artifacts functioned primarily as butchery tools and also imply that hunting and/or aggressive scavenging of large ungulate carcasses may have been part of the behavioral repertoire of Hominids by c . 2.5 Ma, although a larger sample of cutmarked bone specimens is necessary to support the latter inference.
David Pilbeam - One of the best experts on this subject based on the ideXlab platform.
-
morphological affinities of the sahelanthropus tchadensis late miocene Hominid from chad cranium
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Franck Guy, David Pilbeam, Daniel E Lieberman, Marcia Ponce S De Leon, Andossa Likius, Hassane Taisso Mackaye, Patrick Vignaud, Christoph P E Zollikofer, Michel BrunetAbstract:The recent reconstruction of the Sahelanthropus tchadensis cranium (TM 266-01-60-1) provides an opportunity to examine in detail differences in cranial shape between this earliest-known Hominid, African apes, and other Hominid taxa. Here we compare the reconstruction of TM 266-01-60-1 with crania of African apes, humans, and several Pliocene Hominids. The results not only confirm that TM 266-01-60-1 is a Hominid but also reveal a unique mosaic of characters. The TM 266-01-60-1 reconstruction shares many primitive features with chimpanzees but overall is most similar to Australopithecus, particularly in the basicranium. However, TM 266-01-60-1 is distinctive in having the combination of a short subnasal region associated with a vertical upper face that projects substantially in front of the neurocranium. Further research is needed to determine the evolutionary relationships between Sahelanthropus and the known Miocene and Pliocene Hominids.
-
a new Hominid from the upper miocene of chad central africa
Nature, 2002Co-Authors: Michel Brunet, David Pilbeam, Franck Guy, Andossa Likius, Hassane Taisso Mackaye, Djimdoumalbaye Ahounta, Alain Beauvilain, Cecile BlondelAbstract:The search for the earliest fossil evidence of the human lineage has been concentrated in East Africa. Here we report the discovery of six Hominid specimens from Chad, central Africa, 2,500 km from the East African Rift Valley. The fossils include a nearly complete cranium and fragmentary lower jaws. The associated fauna suggest the fossils are between 6 and 7 million years old. The fossils display a unique mosaic of primitive and derived characters, and constitute a new genus and species of Hominid. The distance from the Rift Valley, and the great antiquity of the fossils, suggest that the earliest members of the Hominid clade were more widely distributed than has been thought, and that the divergence between the human and chimpanzee lineages was earlier than indicated by most molecular studies. From their initial description in 1925 1 until 1995, Hominids from the Pliocene (5.3‐1.6 million years, Myr) and late Upper Miocene (,7.5‐5.3 Myr) were known only from southern and eastern Africa. This distribution led some authors to postulate an East African origin for the Hominid clade (where the term ‘Hominid’ refers to any member of that group more closely related to extant humans than to
-
genetic and morphological records of the hominoidea and Hominid origins a synthesis
Molecular Phylogenetics and Evolution, 1996Co-Authors: David PilbeamAbstract:Molecular genetics has had a major impact on phylogenetics, although many hominoid paleontologists and morphologists ignore or remain unaware of genetic data. However, substantial genetic evidence shows chimpanzees and humans as closest relatives. Living hominoids share many postcranial similarities, many of which are retained from the extant hominoid common ancestor. Miocene hominoid fossils consisted until recently mostly of teeth and jaw fragments which are relatively uninformative phylogenetically. As their postcrania have become better sampled, surprisingly few of these taxa share significant similarities with living apes, suggesting that few if any are related to specific extant lineages. Given the genetically inferred relationships of hominoids and the morphology of the earliest Hominids, the common ancestor of humans and chimpanzees was probably chimp-like, a knuckle-walker with small thin-enameled cheek teeth. If correct, this scenario implies that known Miocene hominoids, most of which are postcranially archaic and have large, thickly enameled cheek teeth, throw little if any direct light on Hominid origins.