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1.
Recent genetic studies based on the distribution of mtDNA of haplogroup U6 have led to subtly different theories regarding the arrival of modern human populations in North Africa. One proposes that groups of the proto-U6 lineage spread from the Near East to North Africa around 40–45 ka (thousands of years ago), followed by some degree of regional continuity. Another envisages a westward human migration from the Near East, followed by further demographic expansion at ∼22 ka centred on the Maghreb and associated with a microlithic bladelet culture known as the Iberomaurusian. In evaluating these theories, we report on the results of new work on the Middle (MSA) and Later Stone (LSA) Age deposits at Taforalt Cave in Morocco. We present 54 AMS radiocarbon dates on bone and charcoals from a sequence of late MSA and LSA occupation levels of the cave. Using Bayesian modelling we show that an MSA non-Levallois flake industry was present until ∼24.5 ka Cal BP (calibrated years before present), followed by a gap in occupation and the subsequent appearance of an LSA Iberomaurusian industry from at least 21,160 Cal BP. The new dating offers fresh light on theories of continuity versus replacement of populations as presented by the genetic evidence. We examine the implications of these data for interpreting the first appearance of the LSA in the Maghreb and providing comparisons with other dated early blade and bladelet industries in North Africa.  相似文献   

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3.
The Iberomaurusian necropolis of Taforalt (Morocco, 11-12000 BP), excavated by Roche in the 1950s, contains 28 multiple graves. The funerary practices of the Taforalt population have been the focus of a previous work (Mariotti et al., 2009). In the absence of the excavation records of the necropolis, these funerary practices were investigated through the analysis of the contents of each grave and the distribution of intentionally modified specimens (ochre-dyeing, cut marks). Previous research has drawn particular attention to Grave XII (containing three male adults and two juveniles), where many intentionally modified specimens were identified. The present study focused specifically on the human remains recovered from Grave XII. Analysis of these remains has provided evidence of interventions, such as dismemberment and defleshing of the cadaver, and the use of ochre to colour the bones. Furthermore, the presence of lesions on two skulls suggests the possibility of intentional killing and cannibalism among the Taforalt population. This study further supports our previous impression of the complex and diversified funerary practices, characterising the social life of the Iberomaurusian population of Taforalt.  相似文献   

4.
Diverse tetrapod track assemblages with Scoyenia invertebrate traces were discovered in the Triassic Timezgadiouine and Bigoudine formations of the Argana Basin (Western High Atlas, Morocco). The ichnofossils occur in alluvial plain sandstones and mudstones of the Irohalène Member (T5) and Tadart Ouadou Member (T6) considered Carnian-Norian in age by vertebrate remains and palynomorphs. Tetrapod footprints are assigned to Apatopus, Atreipus-Grallator, Eubrontes isp., Parachirotherium, cf. Parachirotherium postchirotherioides, Rhynchosauroides ispp., and Synaptichnium isp. They can be referred to lepidosauromorph/ archosauromorph, basal archosaur, and dinosauromorph trackmakers. Apatopus, represented by 11 tracks of a more than 4 m long trackway, is recorded for the first time outside of North America and Europe. The assemblage concurs with the proposed Late Triassic age of the track-bearing beds by the occurrence of Apatopus, Atreipus-Grallator, and Eubrontes. If this is accepted, the stratigraphic range of Synaptichnium and Parachirotherium, hitherto known only from Early or Middle Triassic deposits, has to be extended to the Carnian-Norian. The occurrence of Eubrontes in the Irohalene Member (T5) provides further evidence for large theropods in pre-Jurassic strata. All assemblages are referred to the Scoyenia ichnofacies indicating continental environments with alternating wet and dry conditions.  相似文献   

5.
All nine wetland lakes in the CASSARINA North African suite of sample sites have been disturbed strongly by human activity during the 20th century. Dated lake sediment core were used to provide evidence of the extent of recent environmental change at each site. Sedimentary diatoms at seven sites were useful for inferring salinity change trends during the last century. At two sites preservation problems severely degraded the sedimentary diatom record. Sediment core integrity was otherwise established.Lithostratigraphic measurements indicated some site specific changes in soil erosion and sediment composition but, for the Egyptian Delta lakes, no physical signal synchronous with Aswan High Dam construction was found. Sedimentary diatom assemblages were generally site characteristic and halophilous taxa were common. At two sites planktonic diatoms indicated some recent eutrophication but generally the assemblages were more indicative of salinity changes. Diatom-inferred salinity trends for the seven sites typically indicated that reductions in water salinity occurred sometime during the early or mid 20th century.Rather than climate, hydrological modification of water resources is implicated as the primary driver of salinity changes during most of the 20th century. In the western North African region these modifications were mainly local land drainage and water diversion programmes to alleviate winter flooding and/or promote summer water availability. In the Delta region, the Nile has been intensively exploited since antiquity and intensively so from the late 19th century to release more fresh water for agriculture. Here, diatom records indicate that freshening began well before the Aswan High Dam but salinity fluctuations have tended to diminish during the latter part of the 20th century. A small reversal in the water freshening trend in the 1980/90s was possibly a response to land subsidence/sea-level change or to reduced freshwater supply.Freshwater supply to the sites is generally diminishing as former freshwater surpluses switch to deficit. One site (Merja Bokka, Morocco) became completely dry in 1998 as agriculture encroached and Megene Chitane, the only acid lake in Tunisia, is currently affected by excessive inflow abstraction. At the beginning of the 21st century, eight of the nine CASSARINA sites persist as viable but modified aquatic ecosystems. They nevertheless continue to support valuable aquatic biodiversity, especially in the Delta sites and in Chitane. The modern diatom communities are clearly tolerant of considerable environmental change but the remaining sites are increasingly threatened by major hydrological disturbance. Base-line floristic data for the late 20th century are given but continuous biomonitoring combined with effective management is needed urgently to help conserve North Africa's diminishing natural wetland lake resources.  相似文献   

6.
The large-clawed scorpion, Scorpio maurus, is a medically important scorpion and yet nothing is known regarding genetic diversity within this species. As a preliminary analysis we determined variation within the cytochrome oxidase 1 (CO1) mitochondrial gene from specimens from Morocco. High levels of genetic diversity were found that presented some geographical coherence. Of the two identified subspecies from Morocco, S. maurus birulai and S. maurus fuliginosus, the latter included genetically distinct lineages (8.0% uncorrected sequence divergence), indicating a detailed morphological and molecular revision is needed for this species.  相似文献   

7.
Two isolated trunk vertebrae from the ?uppermost Albian–lower Cenomanian Kem Kem beds of Morocco are described and assigned to Lapparentophis, an early snake genus known from coeval deposits in Algeria. The Moroccan specimens represent a new species, Lapparentophis ragei, which can be distinguished from the type and only known species, Lapparentophis defrennei, by its smaller size, its more elongate vertebrae, the presence of parazygosphenal foramina, and paradiapophyses extending anteroventrally closer to the cotyle. The discovery of Lapparentophis in the Kem Kem beds adds to the relatively diverse snake assemblage previously reported from this formation and extends the geographical range of the genus. The distribution of Lapparentophis and lapparentophiid-grade (?lapparentophiid) snakes is discussed. This poorly known family of terrestrial snakes seems to be restricted to the latest Albian–early Cenomanian of North Africa, with the exception of Pouitella from the early–middle Cenomanian of France. As for many other vertebrate taxa of this period, this distribution is consistent with a dispersal event from Africa to the western part of the European archipelago.  相似文献   

8.
Three North African coastal lagoons were selected as primary sites for integrated ecological and hydrological monitoring and modelling as part of the MELMARINA Project (see Flower & Thompson, 2009). The three sites, Merja Zerga (13.2 km2, Morocco), Ghar El Melh (35.6 km2, Tunisia) and Lake Manzala (c. 700 km2, Egypt), are permanent water bodies with at least one well-defined connection with the sea. This article provides an account of each lagoon’s physical characteristics and recent development including the impacts of human activities. The two sites on the Mediterranean (Ghar El Melh and Lake Manzala) are characterised by small tidally driven variations in water level whilst Merga Zerga, on the Atlantic coast, experiences large tidally induced water level variations and so contains large inter-tidal environments. All the three lagoons receive freshwater inflows from their landward margins, varying in magnitude, seasonality and ecological significance. Freshwater inflows from drains strongly influence ecological conditions within Lake Manzala. All the three lagoons have significant biodiversity interest, especially for resident and migratory birds as well as fish, and support local human populations. Each lagoon experienced significant changes during the twentieth century possibly affecting declines in biodiversity value. These largely resulted from agricultural expansion and intensification and include reclamation and hydrological modifications which have both decreased freshwater inflows due to upstream diversions (Merja Zerga and Ghar El Melh) and increased the influx of freshwater through the return of irrigation drainage (Merja Zerga and Lake Manzala). All three sites experienced nutrient enrichment due to agricultural runoff and discharge of domestic wastewater. Industrial waste discharge is a particular, but not exclusive, problem for Lake Manzala. Problems of water quantity and quality will increase through the twenty-first century with increasing demands for water while effects of climate change will enhance freshwater scarcity. Conflicts between human and environmental uses of water will increase and unless improvements in water use efficiency and wastewater treatment can be brought about wetlands including coastal lagoons are likely to suffer further loss and degradation. These problems will be compounded by sea level rise. Guest editors: J. R. Thompson & R. J. Flower Hydro-ecological Monitoring and Modelling of North African Coastal Lagoons  相似文献   

9.
The HGL-50 locality, situated on the Glib Zegdou outlier in the Gour Lazib of Algeria (Hammada du Dra), is famous for having yielded several dental remains of primates dating from the late Early to the early Middle Eocene. These primates include Algeripithecus minutus, Azibius trerki and a new species of cf. Azibius (not described yet). Algeripithecus was widely acknowledged to be one of the oldest known anthropoids from Africa. However, very recent discoveries strongly suggest that Algeripithecus is closely related to Azibius and that both taxa are phylogenetically remote from the clade Anthropoidea. Algeripithecus and Azibius make up the family Azibiidae and appear as stem strepsirhines. Here we describe and analyse two ankle bones (tali) found in HGL-50. UM/HGL50-466 is a small left talus, which is appropriate in size to belong to A. trerki, while UM/HGL50-467 is a right talus, which is significantly larger and appropriate in size to belong to the new large species of cf. Azibius. Both tali exhibit a suite of features that resemble conditions primarily found in extinct and extant strepsirhine and adapiform primates; conditions that are consistent with the strepsirhine-like dentition characterizing azibiids. Functionally, these two tali indicate that Azibius species were engaged in a form of active arboreal quadrupedalism with some ability to climb and leap. Azibiids were rather small-bodied primates, approximating the size of some modern dwarf lemurs (Cheirogaleidae) and sportive lemurs (Lepilemuridae) from Madagascar. Given their small body-size and their talar morphology, living cheirogaleid lemurs, which are agile arboreal quadrupeds (with climbing, springing and branch running activities), might appear as good analogues for azibiids in terms of locomotor behaviour.  相似文献   

10.
Liu Q  Triplett JK  Wen J  Peterson PM 《Annals of botany》2011,108(7):1287-1298

Background and Aims Eleusine

(Poaceae) is a small genus of the subfamily Chloridoideae exhibiting considerable morphological and ecological diversity in East Africa and the Americas. The interspecific phylogenetic relationships of Eleusine are investigated in order to identify its allotetraploid origin, and a chronogram is estimated to infer temporal relationships between palaeoenvironment changes and divergence of Eleusine in East Africa.

Methods

Two low-copy nuclear (LCN) markers, Pepc4 and EF-1α, were analysed using parsimony, likelihood and Bayesian approaches. A chronogram of Eleusine was inferred from a combined data set of six plastid DNA markers (ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL) using the Bayesian dating method.

Key Results

The monophyly of Eleusine is strongly supported by sequence data from two LCN markers. In the cpDNA phylogeny, three tetraploid species (E. africana, E. coracana and E. kigeziensis) share a common ancestor with the E. indica–E. tristachya clade, which is considered a source of maternal parents for allotetraploids. Two homoeologous loci are isolated from three tetraploid species in the Pepc4 phylogeny, and the maternal parents receive further support. The A-type EF-1α sequences possess three characters, i.e. a large number of variations of intron 2; clade E-A distantly diverged from clade E-B and other diploid species; and seven deletions in intron 2, implying a possible derivation through a gene duplication event. The crown age of Eleusine and the allotetraploid lineage are 3·89 million years ago (mya) and 1·40 mya, respectively.

Conclusions

The molecular data support independent allotetraploid origins for E. kigeziensis and the E. africana–E. coracana clade. Both events may have involved diploids E. indica and E. tristachya as the maternal parents, but the paternal parents remain unidentified. The habitat-specific hypothesis is proposed to explain the divergence of Eleusine and its allotetraploid lineage.  相似文献   

11.
Rhabdias rhampholeonis n. sp. from Rhampholeon (Rh.) spectrum, Cameroon, and Rhabdias mariauxi n. sp. from Rieppeleon brevicaudatus, Tanzania, are the first lung worms from leaf chameleons. The new species are similar to the majority of species parasitic in chamaeleonids by having a long (≥10 mm) and thick body (≥500 µm), long oesophagus (≥800 µm), wide buccal capsule (≥40 µm) and low buccal ratio (<0.5). They most closely resemble Rhabdias chamaeleonis and Rhabdias cristati parasitic in Trioceros spp. from East Africa and Cameroon, respectively. Main distinctive characters are a buccal capsule composed of two segments and the head shape. The dorso-ventrally flattened buccal capsule of R. mariauxi n. sp. is unique in Rhabdias parasitising Chamaeleonidae. Sequences of the 12S rDNA and mitochondrial cytochrome c oxidase subunit 1 (coxI) genes were obtained and compared to those of Rhabdias okuensis, the only sequences published for chamaeleonid lung worms. The smallest nucleotide interspecific distances were found between R. mariauxi n. sp. and the former species of Trioceros from Cameroon. Hermaphroditism in females in the lungs, and R. mariauxi n. sp. free-living stages are like in other species from Chamaeleonidae, but the number of infective larvae produced per free-living female (one or two) was not fixed.  相似文献   

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