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Lee-Thorp J.,University of Oxford | Likius A.,University Of Ndjamena | Mackaye H.T.,University Of Ndjamena | Vignaud P.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments | And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2012

Foods derived from C4 plants were important in the dietary ecology of early Pleistocene hominins in southern and eastern Africa, but the origins and geographic variability of this relationship remain unknown. Carbon isotope data show that Australopithecus bahrelghazali individuals from Koro Toro in Chad are significantly enriched in 13C, indicating a dependence on C4 resources. As these sites are over 3 million years in age, the results extend the pattern of C4 dependence seen in Paranthropus boisei in East Africa by more than 1.5 million years. The Koro Toro hominin fossils were found in argillaceous sandstone levels along with abundant grazing and aquatic faunal elements that, in combination, indicate the presence of open to wooded grasslands and stream channels associated with a greatly enlarged Lake Chad. In such an environment, the most abundant C4 plant resources available to A. bahrelghazali were grasses and sedges, neither of which is usually considered as standard great ape fare. The results suggest an early and fundamental shift in hominin dietary ecology that facilitated the exploitation of new habitats.

Novello A.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments | Barboni D.,Aix - Marseille University
Journal of Archaeological Science | Year: 2015

Dendritic phytoliths that precipitate in grass inflorescences are often used in archaeology to trace the use of cereals (i.e. grasses harvested for their edible grain) and their domestication by early human societies. High amounts of these morphotypes are sometimes interpreted in terms of cereal accumulation in archaeological contexts. In sub-Saharan Africa, few cereals were domesticated during the mid-Holocene, but many wild grasses are still largely harvested by modern societies for food. The harvesting of wild cereals is also considered as one of the first stages toward early grass domestication. To evaluate how well dendritic phytoliths and/or other phytoliths produced in the grass inflorescences could help trace the use of wild cereal grains in sub-Saharan Africa, we analyzed the phytolith content of 67 African species (including 20 wild cereals), and 56 modern soils. We used test-value analysis and ANOVA to evaluate how well grass inflorescences could be distinguished from leaf/culm parts based on their phytolith content. We also measured the abundances of these phytoliths in natural soils from sub-Saharan Africa to provide a benchmark percentage abundance above which anthropogenic accumulation may be suspected in archaeological deposits. Our results confirm that, although rondel type phytoliths are abundant, only the dendritic phytolith morphotype is exclusive to the grass inflorescences. Yet, dendritic phytoliths do not occur in all species. They happen to be most frequent and found in greatest abundance (>34% relative to total phytolith count) in Panicoideae grasses (. Sehima ischaemoides, Sorghastrum stipoides, and Sorghum purpureo-sericeum), and in one Eragrostideae species (. Eragrostis squamata), which are not considered cereals. Inflorescences of the wild African cereals studied here do not happen to be particularly rich in dendritics (<7% in average). Finally, dendritics are rare in modern natural soils (<1% relative to total phytolith count, <3% relative to sum of grass silica short cells plus dendritics), even under stands of rich dendritic producers. We conclude that dendritic phytoliths may be used for tracing remarkable deposits of grass inflorescences at archaeological sites in sub-Saharan Africa, but are not exclusive to domesticated or wild cereals. Abundances of dendritics »3% relative to sum of grass silica short cell phytoliths plus dendritics are likely to indicate anthropogenic accumulation of grass inflorescences. Yet, the absence or low abundance of dendritic phytoliths in archaeological deposits may not always indicate the absence of anthropogenic accumulation of grass inflorescence material. © 2015 Elsevier Ltd.

Ducrocq S.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments | Manthi F.K.,Palaeontology Section | Lihoreau F.,Montpellier University
Journal of Human Evolution | Year: 2011

Recent excavations in northwestern Kenya have recovered a vertebrate fauna of late early or early late Oligocene age. Among the mammal remains, a fragmentary lower jaw and an isolated upper molar have been attributed to a small primate, Lokonepithecus manai gen. et sp. nov. Lokonepithecus is a primitive member of the Parapithecidae and possibly most closely related to Apidium from the Fayum. The new primate from Kenya is the youngest parapithecid known and its occurrence in the Oligocene of Kenya suggests that sub-Saharan Africa probably played a major role in the evolutionary history of several groups of mammals. © 2011 Elsevier Ltd.

Orliac M.J.,Montpellier University | Ducrocq S.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Geological Magazine | Year: 2012

Raoellidae are small fossil cetartiodactyls closely related to the Cetacea. Until now undisputable raoellid remains were reported only from the early Middle Eocene of the Indian Subcontinent, although this Indo-Pakistani endemism has been challenged by several recent works describing potential raoellids from Mongolia, Myanmar and China. In this contribution we address the question of raoellid taxonomic content and definition, through a revision of the dental features of the family. This work, which includes a revision of the putative raoellid material from outside Indo-Pakistan, is primarily based on a re-examination of 'suoid' specimens from Shanghuang (Middle Eocene, coastal China). Our results indicate that the Shanghuang material both substantiates the youngest and easternmost occurrence of Raoellidae and represents the only unquestionable record of raoellids outside the Indian Subcontinent at present. This significantly extends the geographical and chronological range of the family. The occurrence of a raoellid species in the Middle Eocene of coastal China implies that raoellids dispersed from the Indian Subcontinent to eastern Asia during Early or Middle Eocene time. This tempers classical hypotheses of Middle Eocene Indian endemism and eastern Asian provincialism. © Copyright Cambridge University Press 2011.

Reed K.E.,Arizona State University | Bibi F.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Journal of Mammalian Evolution | Year: 2011

The fossil tragelaphins from the late Pliocene of Hadar are described. These are Tragelaphus lockwoodi, new species, and Tragelaphus aff. T. nakuae. Tragelaphus lockwoodi bears long horns that define one complete spiral and that are mediolaterally compressed at the base. In these and other morphological characteristics it approaches the greater kudu, T. strepsiceros, and makes a good ancestral candidate for this living species. The Hadar T. aff. T. nakuae is similar to other specimens of this species from sites >2.8 Ma in East Africa and demonstrates well the major differences between the earlier and later representatives of this taxon. The sizes and morphological variation in the large Hadar T. aff. T. nakuae sample supports the idea that female individuals of this species were horned as is the case today in the elands and the bongo. Tragelaphus lockwoodi is present only in the lower beds of the Hadar Formation, and in small numbers, while T. aff. T. nakuae is recovered in relative abundance from throughout the ca. 3.4-ca. 2.9 Ma sequence. © 2010 Springer Science+Business Media, LLC.

Licht A.,University Paris Diderot | Licht A.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments | Hulot G.,University Paris Diderot | Gallet Y.,University Paris Diderot | Thebault E.,University Paris Diderot
Physics of the Earth and Planetary Interiors | Year: 2013

We introduce ensembles of time-varying archeomagnetic field models, consisting of a reference model, a mean model and a thousand individual models. We present a set of three such ensembles, built from archeomagnetic, volcanic and sedimentary data sets, that cover the past three millennia. These ensembles can be used to describe the field at any location from the core surface to the magnetosphere, and assess the way uncertainties due to the limited distribution and quality of the data affect any of its component or parameter, such as individual Gauss coefficients. They provide alternative - and, we argue, more complete - descriptions of the archeomagnetic field to those provided by previously published archeomagnetic field models, being better suited to existing and emerging needs, such as those of geomagnetic data assimilation. We present the data sets we rely on - essentially the same as those used by other recent archeomagnetic field models - and describe how errors affecting the data, and errors due to non-modelled small spatial scales of the field, are taken into account. We next explain our modeling strategy and motivation for building low degree spherical harmonic degree ensembles of models. We carry on a number of end-to-end simulations to both illustrate the usefulness of such ensembles and point at the type of errors one should expect. Practical illustrations of what can be done with these three ensembles of models, with examples of geomagnetic inferences, are also described. Northern high-latitude flux patches, for instance, appear to be the most robust features of all. These patches tend to fluctuate, but clearly have some favored locations, resulting in the same clear signature with three tongues (over Northern America, Europe and Asia) in the time-averaged field at the core-mantle boundary, similar to what had been found in earlier models. Inferences about the field behavior in the Southern hemisphere are more difficult to draw. Still, some suggestions that the well-known present South Atlantic reversed patch could have arisen as early as in 1500 A.D. are found in some of the ensembles. We otherwise confirm that most of the current archeomagnetic field model limitations are related to a number of sediment cores, identified as producing frequent outliers in the modeling process. We provide evidence that such cores are likely affected by timing errors and timing delays between magnetization lock-in and sediment deposition, that future more advanced treatment should be able to handle. All source files for the three ensembles of models, together with appropriate Matlab applications can be downloaded from http://geomag.ipgp.fr/download/ARCHEO_FM.zip. © 2013 Elsevier B.V.

Neaux D.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Anatomical record (Hoboken, N.J. : 2007) | Year: 2013

Previous studies showed that in modern humans the basicranium is formed of two modules: the midline cranial base and the lateral basicranium which are integrated with the face in very different ways. The study of the relationship between these structures is of prime interest in the context of hominids craniofacial evolutionary history. In this study, we aim to test if the relationship between the midline cranial base and the face on one hand and the lateral basicranium and the face on the other hand are qualitatively and quantitatively different in modern humans and chimpanzees: two phylogenetically close but morphologically different hominids. This work is performed using three-dimensional (3D) landmarks to take into account the face and basicranium 3D shape. Modern humans and chimpanzees both exhibit a significant relationship between lateral basicranium and face, and a nonsignificant relationship between midline cranial base and face. However, the patterns of integration are different for the two species. These results underscore the essential role of the lateral basicranial shape in the setting of the facial morphology in modern humans and chimpanzees. The important differences in the patterns of integration may be related to the genetic, developmental, and functional requirements of each taxon, acquired along their respective evolution. From a common, tight, relationship between lateral basicranium, and face, each taxon may develop different patterns of integration in order to adapt to particular functions and morphologies. Copyright © 2013 Wiley Periodicals, Inc.

Chaimanee Y.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Proceedings. Biological sciences / The Royal Society | Year: 2013

According to the most recent discoveries from the Middle Eocene of Myanmar and China, anthropoid primates originated in Asia rather than in Africa, as was previously considered. But the Asian Palaeogene anthropoid community remains poorly known and inadequately sampled, being represented only from China, Myanmar, Pakistan and Thailand. Asian Eocene anthropoids can be divided into two distinct groups, the stem group eosimiiforms and the possible crown group amphipithecids, but the phylogenetic relationships between these two groups are not well understood. Therefore, it is critical to understand their evolutionary history and relationships by finding additional fossil taxa. Here, we describe a new small-sized fossil anthropoid primate from the Late Eocene Krabi locality in Thailand, Krabia minuta, which shares several derived characters with the amphipithecids. It displays several unique dental characters, such as extreme bunodonty and reduced trigon surface area, that have never been observed in other Eocene Asian anthropoids. These features indicate that morphological adaptations were more diversified among amphipithecids than was previously expected, and raises the problem of the phylogenetic relations between the crown anthropoids and their stem group eosimiiforms, on one side, and the modern anthropoids, on the other side.

Bibi F.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
PLoS ONE | Year: 2011

The development of the Ethiopian biogeographic realm since the late Miocene is here explored with the presentation and review of fossil evidence from eastern Africa. Prostrepsiceros cf. vinayaki and an unknown species of possible caprin affinity are described from the hominid-bearing Asa Koma and Kuseralee Members (~5.7 and ~5.2 Ma) of the Middle Awash, Ethiopia. The Middle Awash Prostrepsiceros cf. vinayaki constitutes the first record of this taxon from Africa, previously known from the Siwaliks and Arabia. The possible caprin joins a number of isolated records of caprin or caprin-like taxa recorded, but poorly understood, from the late Neogene of Africa. The identification of these two taxa from the Middle Awash prompts an overdue review of fossil bovids from the sub-Saharan African record that demonstrate Eurasian affinities, including the reduncin Kobus porrecticornis, and species of Tragoportax. The fossil bovid record provides evidence for greater biological continuity between Africa and Eurasia in the late Miocene and earliest Pliocene than is found later in time. In contrast, the early Pliocene (after 5 Ma) saw the loss of any significant proportions of Eurasian-related taxa, and the continental dominance of African-endemic taxa and lineages, a pattern that continues today. © 2011 Faysal Bibi.

Bibi F.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments
Zoological Journal of the Linnean Society | Year: 2011

Fossil Bovidae constitute one of the most significant proxy records for evolutionary and palaeoecological change in Africa. Tragelaphus nakuae is a regularly encountered antelope in the East African Plio-Pleistocene, and is a common component of hominin faunas. As previously understood, this species ranged for almost 2 million years, encompassed a large range of morphological variation, exhibited relative stasis in the face of environmental perturbations, and left no known living descendants. I here review and revise the fossil record of this tragelaphin bovid, finding that specimens older than ∼2.8Mya and previously attributed to T. nakuae or a close form are in fact referable to a distinct, but ancestral, species. This new interpretation adds these fossil tragelaphins to the body of evidence supporting major faunal turnover occurring around 2.8Mya in concert with global climatic change. I also document morphological changes that occur through the duration of T. nakuae, particularly after 2.3Mya. These taxonomic revisions allow for refined biochronological estimates for several East African Plio-Pleistocene sites and specimen assemblages of uncertain age. A phylogenetic analysis suggests that the T. nakuae lineage is related to the extant bongo (Tragelaphus eurycerus), relating this living but enigmatic forest antelope to the fossil record. One resulting palaeoecological hypothesis is that the bongo's modern fragmented range represents the relicts of a much more widely distributed late Pliocene African forest belt. This study highlights the importance of specimen-based approaches for elucidating the pattern and timing of major evolutionary events. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society.

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