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Bernor R.L.,Howard University | Boaz N.T.,International Institute for Human Evolutionary Research | Boaz N.T.,Virginia Commonwealth University | Rook L.,University of Florence
Bollettino della Societa Paleontologica Italiana | Year: 2012

The discovery of a new hipparionine metacarpal III in 2010 has led to the recognition of the occurrence of the East African species Eurygnathohippus feibeli at Sahabi. Specimens of metacarpal III and metatarsal III previously referred to cf. Hipparion s.s. are reassigned herein to Eurygnathohippus feibeli. The occurrence of an East African hipparionine horse at Sahabi is congruent with findings of other Late Miocene ungulates and strengthens the biogeographic connections between the Sahabi and the Ethiopian Middle Awash and Kenyan Lothagam faunas. Taking into consideration the known biogeographic connections to eastern Mediterranean - Southwest Asia faunas, the Sahabi findings constitute a crucial crossroads fauna between Eurasia and Africa and reflect the maximum extension of Old World Pikermian faunas in the Late Miocene. Source

El-Shawaihdi M.H.,New Mexico Institute of Mining and Technology | Muftah A.M.,University of Benghazi | Mozley P.S.,New Mexico Institute of Mining and Technology | Boaz N.T.,Virginia Commonwealth University | Boaz N.T.,International Institute for Human Evolutionary Research
Journal of African Earth Sciences | Year: 2014

For almost half a century researchers have attempted to determine the absolute ages of Neogene sedimentary units in the Sahabi area of Libya. The age of these sediments is of particular interest to paleontologists who have worked on important vertebrate remains in the area since the late 1970s. To date, several geochronological methods have been attempted; however, no precise ages have been obtained for the various units. In this paper we report data for calcareous nannofossils and strontium isotope (87Sr/86Sr) analysis of macrofossils, which can be used to infer age of deposition of part of the Neogene section (Formation M). Because most Sahabi fossils are extensively altered by various diagenetic processes, including gypsification and dolomitization, we carefully screened tens of samples to select unaltered material for analysis. Among the many fossils collected from Formation M and analyzed by XRD, only two, Balanus sp. and a Cubitostrea digitalina show no evidence of diagenetic alteration of their shells, and thus retain their original low-Mg calcite (LMC) mineralogy. The strontium isotopic values from these fossils were plotted against the marine strontium isotopic curve, in order to infer the absolute age. The Balanus sp. has a 87Sr/86Sr value of 0.708917, whereas C. digitalina has a 87Sr/86Sr value of 0.708908. Based on the current estimated error (0.000008), the value of 0.708917 indicates an ages between 9.33Ma and 8.59Ma, centered on 8.99Ma, whereas the value of 0.708908 indicates ages between 9.61 and 9.03Ma, centered on 9.36Ma. The calcareous nannofossils found in this formation belong to biozone NN10b-NN11a and provide an age of 8.23Ma. These ages fall in the Late Miocene period (Tortonian Epoch). Therefore, Formation M should be considered Late Miocene (Tortonian) rather than Middle Miocene (Serravallian) as proposed by many previous workers. Age dating of Formation M will help in revising the stratigraphic nomenclature as well as in re-evaluating the stratigraphic position of this formation according to the Libyan Stratigraphic Code through the Earth Science Society of Libya (ESSL). © 2013 Elsevier Ltd. Source

Argyriou T.,National and Kapodistrian University of Athens | Argyriou T.,University of Alberta | Otero O.,CNRS Institute of Paleoprimatology, Human Paleontoly: Evolution and Paleoenvironments | Otero O.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments | And 4 more authors.
Geobios | Year: 2012

Fossils recently found in the Late Miocene of Sahabi, Libya, are attributed to the extinct species. Semlikiichthys rhachirhinchus. This study enriches our knowledge of the anatomy of this species. The hyomandibula and, putatively, the operculum are for the first time attributed to. Semlikiichthys. The fragile laminar supraoccipital crest in the dorsicranium is preserved complete. The material from Sahabi described here extends the Late Miocene distribution of the species to the north and west to include Libya. The paleobiogeographic distribution of. Semlikiichthys in Africa, and the freshwater faunal connections between different hydrographical basins in north central Africa, are discussed. © 2012 Elsevier Masson SAS. Source

Muftah A.M.,National and Kapodistrian University of Athens | Muftah A.M.,University of Benghazi | Pavlakis P.,National and Kapodistrian University of Athens | Pavlakis P.,International Institute for Human Evolutionary Research | And 5 more authors.
Journal of African Earth Sciences | Year: 2013

A large paleo-river of Miocene age traversing Libya from south to north has been previously demonstrated by seismic, stratigraphic, paleontological, and remote sensing data. The depositional environment of As Sahabi Formation in north central Libya is this large and now extinct Eosahabi River. However, the source of this major African river has remained controversial. Dark-colored sedimentary material with magnetic properties suggested a source from the basaltic Haruj as Aswad massif in south central Libya. To test this hypothesis, mineralogical and geochemical study of clayey sediments from three localities, P25, P28 and P96c, from fossiliferous Member U1 of the As Sahabi Formation, were carried out. Results strongly indicate very mature and re-processed sediments of continental origin, and felsic sources with no basaltic contribution. Thus the origin can be traced to an upland area of outcrop of rocks of Precambrian continental origin in northeastern Chad. An alternative scenario is that the Sahabi sediments originated from Precambrian outcrops in Ethiopia through an east-west river connection with the Nile. We consider this hypothesis unlikely, since it is based only on remote sensing data, and lacks any time control or geological supporting evidence. The abundant vertebrate fauna from the Sahabi Formation shows strong similarities with penecontemporaneous fossil faunas in Chad and is supportive of an origin of the Eosahabi River in Neogene mega-Lake Chad. © 2012 Elsevier Ltd. Source

Argyriou T.,University of Alberta | Cook T.D.,University of Alberta | Cook T.D.,The Behrend College | Muftah A.M.,University of Benghazi | And 5 more authors.
Journal of African Earth Sciences | Year: 2015

Recent excavations and prospecting in the early to middle Miocene deposits of the Maradah Formation in Jabal Zaltan, Libya, yielded a diverse fish assemblage coming from an early Miocene locality. The material described here includes more than 18 marine and freshwater taxa most of which were previously unreported from the area. Jabal Zaltan is one of the very few early Miocene Afroarabian fossil sites that produced such a diverse fish sample. Therefore, the fossils described here provide a unique insight into the composition of the early Miocene fish faunas from the northern African coast; a critical time period for faunas of the continent, as contact with Eurasia ended 100 million years of African isolation. In addition, the Jabal Zaltan fossils help consolidate the validity of Galeocerdo mayumbensis and extend its geographic range to include the Tethys. The Maradah deposits also host the first occurrences of two genera (. Pteromylaeus, Distichodus) in the fossil record. The fish finds support the presumed depositional environment that of tropical shallow estuarine to deltaic conditions, and the freshwater fishes document the presence of a modern-type Nilosudanian fauna containing elements with both African and Asian affinities. The Jabal Zaltan ichthyofauna, with its diversity of taxa, has the potential to become a key reference fauna for future studies of early Miocene African fishes. © 2014 Elsevier Ltd. Source

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