An Early Cretaceous vertebrate assemblage from the Cabao Formation of NW Libya

Fossil vertebrates from the Cabao Formation discovered in the area of Nalut in northwestern Libya include the hybodont shark Priohybodus, the crocodilian Sarcosuchus, an abelisaurid, a baryonichine spinosaurid and a large sauropod with spatulate teeth. The Cabao Formation may be Hauterivian to Barremian in age, although an earlier Berriasian to Valanginian age cannot be excluded. Its dinosaur assemblage is reminiscent of that of the El Rhaz and Tiouraren formations of Niger and strongly differs from both the Cenomanian assemblages of Morocco and Egypt and the Late Aptian to Albian fauna of Tunisia. Fossil vertebrates may be an important tool to establish the stratigraphical framework of the poorly dated Early Cretaceous continental deposits of Afric

Discovery of an earliest Pliocene relic tropical fish fauna in a newly detected cliff section (Sabratah Basin, NW Libya)

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New insight into the sedimentology and stratigraphy of the Dur At Talah tidal-fluvial transition sequence (Eocene-Oligocene, Sirt Basin, Libya)

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New rodent assemblages from the Eocene Dur At-Talah escarpment (Sahara of central Libya): systematic, biochronological, and palaeobiogeographical implications

International audienceIn this paper, we describe four fossil rodent taxa from two new localities situated in the Idam Unit ('Bioturbated Unit) of the Dur At-Talah escarpment in central Libya These rodents belong to the family Phiomyidae (Hys tricognathi) and are distributed amongst three genera (Phiomys, Protophiomys, and Talahphiomys gen. nov.) that include three new species (Phiomys hammudai sp. nov., Protophiomys durattalahensis sp. nov., and Talahphiomys libycus sp. nov.). Although some of these new species are inorphologically close to certain phiomyids from the latest Eocene and Oligocene of the Jebel elQatrani Formation of the Fayum in Egypt, the Idam rodent faunas lack the abundant and somewhat morphologically derived Fayum phiomyids (such as: Metaphiomys, Gaudearnus, Paraphiornys, Phiocricetomys), thereby excluding a similar age for the Dur At-Talah rodent assem blages. More resemblance is shared with the phiomyid (Protophiomys algeriensis) of the Nementcha locality in Algeria, for which a late middle Eocene age is presently admitted. Protophiomys is a primitive representative of the phiomyid African radiation and it is represented at Dur At-Talah by a slightly more derived species (Pr. durattalahensis) than that of Nementcha, thereby suggesting a younger age for Dur AtTalah. As a result, the new rodent assemblages suggest a late middle Eocene age for the Idam ('Bioturhated) deposits of the Dur At-Talah escarpment. This age hypothesis is substantiated by other mammals (especially Proboscidea), which occur in the same sedimentological unit. Interestingly, the dental pattern of Protophiornys and that of Talahphzomys have somewhat stronger affinities with South Asian hystricognath baluchimyines than with Fayum phiomyids. It is clear that haluchimyines and phiomyids have a common ancestry, and that dispersal occurred between Asia and Africa during the middle of the Palaeogene. However, it is not clear if both groups can be strictly separated in two distinct natural groups inasmuch as some haluchimyines (e.g Lophthaluchia, Bugtirnys, Hodsahibia) appear to be phioinyid4ike, and some early members of phiomyids (e.g. Protophiomys, Talahphiomys) are baluchimyine4ike. South Asia and North Africa represent two centres of adaptive radiation of early hystricognathous rodents. The strong dental resemblances between early Asian and African forms are perhaps the result of subsequent convergent evolution after an initial dispersal from Asia, Otherwise, the systematics of these rodents has to be entirely revised, or we must consider that their historical biogeography is much more complex. (C) 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 195-213

New rodent assemblages from the Eocene Dur At-Talah escarpment (Sahara of central Libya): systematic, biochronological, and palaeobiogeographical implications

International audienceIn this paper, we describe four fossil rodent taxa from two new localities situated in the Idam Unit ('Bioturbated Unit) of the Dur At-Talah escarpment in central Libya These rodents belong to the family Phiomyidae (Hys tricognathi) and are distributed amongst three genera (Phiomys, Protophiomys, and Talahphiomys gen. nov.) that include three new species (Phiomys hammudai sp. nov., Protophiomys durattalahensis sp. nov., and Talahphiomys libycus sp. nov.). Although some of these new species are inorphologically close to certain phiomyids from the latest Eocene and Oligocene of the Jebel elQatrani Formation of the Fayum in Egypt, the Idam rodent faunas lack the abundant and somewhat morphologically derived Fayum phiomyids (such as: Metaphiomys, Gaudearnus, Paraphiornys, Phiocricetomys), thereby excluding a similar age for the Dur At-Talah rodent assem blages. More resemblance is shared with the phiomyid (Protophiomys algeriensis) of the Nementcha locality in Algeria, for which a late middle Eocene age is presently admitted. Protophiomys is a primitive representative of the phiomyid African radiation and it is represented at Dur At-Talah by a slightly more derived species (Pr. durattalahensis) than that of Nementcha, thereby suggesting a younger age for Dur AtTalah. As a result, the new rodent assemblages suggest a late middle Eocene age for the Idam ('Bioturhated) deposits of the Dur At-Talah escarpment. This age hypothesis is substantiated by other mammals (especially Proboscidea), which occur in the same sedimentological unit. Interestingly, the dental pattern of Protophiornys and that of Talahphzomys have somewhat stronger affinities with South Asian hystricognath baluchimyines than with Fayum phiomyids. It is clear that haluchimyines and phiomyids have a common ancestry, and that dispersal occurred between Asia and Africa during the middle of the Palaeogene. However, it is not clear if both groups can be strictly separated in two distinct natural groups inasmuch as some haluchimyines (e.g Lophthaluchia, Bugtirnys, Hodsahibia) appear to be phioinyid4ike, and some early members of phiomyids (e.g. Protophiomys, Talahphiomys) are baluchimyine4ike. South Asia and North Africa represent two centres of adaptive radiation of early hystricognathous rodents. The strong dental resemblances between early Asian and African forms are perhaps the result of subsequent convergent evolution after an initial dispersal from Asia, Otherwise, the systematics of these rodents has to be entirely revised, or we must consider that their historical biogeography is much more complex. (C) 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 195-213

Late middle Eocene epoch of Libya yields earliest known radiation of African anthropoids.

International audienceReconstructing the early evolutionary history of anthropoid primates is hindered by a lack of consensus on both the timing and biogeography of anthropoid origins. Some prefer an ancient (Cretaceous) origin for anthropoids in Africa or some other Gondwanan landmass, whereas others advocate a more recent (early Cenozoic) origin for anthropoids in Asia, with subsequent dispersal of one or more early anthropoid taxa to Africa. The oldest undoubted African anthropoid primates described so far are three species of the parapithecid Biretia from the late middle Eocene Bir El Ater locality of Algeria and the late Eocene BQ-2 site in the Fayum region of northern Egypt. Here we report the discovery of the oldest known diverse assemblage of African anthropoids from the late middle Eocene Dur At-Talah escarpment in central Libya. The primate assemblage from Dur At-Talah includes diminutive species pertaining to three higher-level anthropoid clades (Afrotarsiidae, Parapithecidae and Oligopithecidae) as well as a small species of the early strepsirhine primate Karanisia. The high taxonomic diversity of anthropoids at Dur At-Talah indicates either a much longer interval of anthropoid evolution in Africa than is currently documented in the fossil record or the nearly synchronous colonization of Africa by multiple anthropoid clades at some time during the middle Eocene epoch