Ostracodes du Dévonien moyen et supérieur du Tafilalt (Maroc)

Forty-four ostracod species are recognised from the upper part of the Eifelian to the base of the Famennian of the Djebel Mech Irdane, Bou Tchrafine and El Atrous sections, in the Tafilalt. The majority are in open nomenclature, and one is new: Tubulibairdia tafilaltensis nov. sp. Ostracods belong principally to the Eifelian Mega-Assemblage and they are generally indicative of poorly oxygenated relatively deep marine environments below storm wave base. However, in the base of the Famennian of the Bou Tchrafine section, ostracods belong to the Myodocopid Mega-Assemblage indicative of strong hypoxic water conditions. They confirm that the hypoxic water conditions linked to the “Upper Kellwasser Horizon”, subsisted in North Africa, in the extreme base of the Famennian. Twenty-four ostracod species are recognized in the Djebel Mech Irdane Eifelian/Givetian stratotype, where the most important change in the ostracod fauna is related to the 40 cm-thick level of grey silty-marl located 10 cm below the boundary. However, this change is not indicative of an extinction event at this level. Three zones established on ostracods are recognized in the Frasnian and in the base of the Famennian of the Tafilalt.     

Les ostracodes du Néogène supérieur du littoral nord-ouest marocain entre Tanger et Asilah

Ostracodes populations have been studied in 19 samples from the upper Neogene of the Atlantic coast of NW of Morocco, between Tangier and Asilah. One hundred and two species belonging to 53 genera have been indentified. Analysis of the species assemblages allowed to reconstruct the palaeoenvironmental evolution of these deposits. This begins with the transgression of the upper Tortonian which corresponds to a relatively deep circalittoral environment. The series continues by deposits showing a general regressive character, punctuated by few transgressives pulses. Shallowing starts at the end of the upper Tortonian with the deposition of calcarenites in massive banks, in an infralittoral exposed environment. This facies pass towards the top to a detrital facies, assigned to the Messinian and deposited under high energy conditions in a shallow-marine environment. The lower Pliocene transgression shows a more generalized character. The maximum deepening corresponds to the grey clay facies deposited in the external infralittoral environment, relatively protected and rich in phytal biotopes. The more recent deposits are shallower, from coastal environments, and show a more limited extension.     

Phylloceratoidea du Jurassique moyen et supérieur du Nord-Est de l’Iran (Monts Binalud)

Phylloceratidae are often the most frequent taxa within the Middle and Late Jurassic ammonite faunas of North Iran but so far they have not been noticed much within the existing literature and have been described only sporadically. In this study, the Phylloceratidae of north Iran are treated systematically and described comprehensively. These include 16 taxa, most of them being previously unpublished for Iran.     

Des Miliolacea aux Alveolinacea (grands foraminifères): la faune du Crétacé supérieur et du Tertiaire inférieur du Chiapas (S.E. Mexique)

Found in Chiapas (South-East of Mexico), Praealveolina michaudi nov. sp. and Chubbina jamaicensis (of Campanian-Maestrichtian age) are described, both evolved from Nummoloculina sp. while Raadshoovenia guatemalensis (upper Paleocene-lower Eocene) arises from Quinqueloculina. We precisely analyze and modelize the nepionic coiling during the evolutionary change from Miliolacea to Alveolinacea. During ontogenesis as well as during phylogenesis, quinqueloculine coiling progresses to streptospiral and then to planispiral chamber arrangement with the increase of volume of embryo and of chambers. Appearance of these large foraminifers are understood as a consequence of the rise of K-strategies in their mode of life, following the development of photosynthetic symbioses.     

Trilobites Calmoniidae de l'Ordovicien supérieur du Maroc et les origines de la Province Malvino-Cafre

A re-examination of the trilobite Baniaspis globosa Destombes (Phacopina) from the Ashgill of the Anti-Atlas (Morocco) shows that it has several derived characters which allow us to classify it in the family Calmoniidae. Calmoniids were characteristic members of the Malvino-Kaffric province during the Lower Devonian. Hence we regard the origins of this palaeogeographic province as located on the northern Gondwanan margin as early as Ashgill, or even Caradoc, times. We agree with those authors who have suggested that the trilobite associations present in the Anti-Atlas, the Montagne Noire (France) and Bohemia during the earlier Ordovician argue against the existence of a 'proto-Tethys' ocean.     

Matière organique sédimentaire et paléoenvironnements du Tithonien inférieur quercynois (France)

The Solen 98 well corresponds to the limestones of the Lower Tithonian Cazals Formation (Gigas Zone). The iterative succession of six sedimentary terms expresses a cyclic peritidal dynamic. Limited by two emersion surfaces, each sequence evolves from an upper subtidal lagoon to a tidal flat, upper intertidal or supratidal environment, and ends with open sea depositional bioclastic and oolitic shoals deposits. Hierarchical ascendant classification applied to palynological data define 6 palynofacies types associated with different depositional facies. Type 1, characterizing open marine deposits, shows a diversified and balanced assemblage. The blade-shape woody particles are abundant and the amorphous organic matter is absent. Types 2 and 3 are linked to lagoonal and skeletal shoals deposits. Then microfossil population is dominated by Corculodinium or long-spine Micrhystridium. The Shannon-Weaver and the equitability indices are moderate. Type 4 is associated with the upper tidal flat, lagoonal and skeletal shoal deposits. When microfossils are present, the algal assemblages are more balanced than in type 5. This type, observed in all the palaeo-environments except the open marine, is enriched in elements attributed to the Hyalinsphaeridia complex. The marine component assemblages are balanced. The amorphous organic matter is relatively abundant and the oxydized woody particles absent. Type 6, mainly composed of amorphous organic matter and phytoclasts, is principally associated with the stromatolitic facies of tidal flat deposits. The example of the Solen 98 well, shows that hierarchical ascendant classification method is well suited for identification of palynofacies     

Cyprididae (Ostracoda) du Miocène supérieur du Bassin de Turiec (Slovaquie) : Taxonomie et Paléoécologie

Twelve species of the family Cyprididae were found in the Upper Miocene of the Turiec Basin, of which three are new - Herpetocypris denticulata nov. sp., H. pusilla nov. sp. et Psychrodromus janzi nov. sp. The occurrence of Mediocypris suggests that ostracods occupied the Turiec Basin since the Middle Miocene. The psychrophilic genera (Psychrodromus and Cavernocypris) provide evidence of cold springs around the lake. In the sediments studied, the Cyprididae are associated with other ostracods that characterise shallow aquatic habitats and a diverse community of both aquatic and terrestrial plants. The sexual paleo-populations of Heterocypris salina (Brady, 1868), Herpetocypris pusilla nov. sp. and Psychrodromus janzi nov. sp. are observed.     

Morphologie, fonction et évolution de quelques grains de pollen normapolles du Crétacé supérieur

Upper Cretaceous pollen grains with a thick wall (exine) and sometimes protruding apertures, included in the Normapolles Pflug, are considered from a functional point of view. Because of the high development of compression-resistance features correlative with a high protection of the gametophyte, an entomophilic phase is supposed in the dissemination of some types, but anemophily appears to have been a developmental trend of apertural specialization for others. As these functional features are characteristic of the outer part of the wall (the sexine), the tetrahedral morphology of the inner part (the nexine) and the lack of evidence that it influenced the whole adaptive system suggest that angiospermic constraints have acted first at a pteridophytic stage.     

La gestion du quartz au Pléistocène moyen et supérieur. Trois exemples d’Europe Méridionale

Quartz is one of the main lithic resources employed along the Pleistocene for the manufacturing of tools. The abundance in all kind of environments leads to its frequent presence in archaeological sites. In spite of its suitability for knapping, the scarcity of specific researches on quartz industries has led to a view of this raw material as a second-rate resource, only used when flint was not available in the surroundings. Quite in opposition to this prejudice, the familiarity with the petrological and mechanical properties of the different varieties of quartz has led the Middle/Upper Pleistocene groups to a rational and differential exploitation of the available resources. There is a distinct selection of the varieties attending to the purposes of the exploitation and configuration. The patterns of exploitation of the cores are very standardized, based on longitudinal extractions and documenting the bipolar flaking technique. Moreover, when the raw material is of good quality, more sophisticated reduction methods such as the discoidal or the Levallois may be employed. On the other hand, for the purposes of configuration a clearly differential management of the raw material is attested: thus quartz is used for the small products (denticulates, side-scrapers, notches), while other stones (quartzite, porphyry and others) are devoted to the manufacturing of those tools demanding a more complex control of the elaboration (bifaces, cleavers, etc.). Either acting as the main lithic resource or as a complement to other raw materials, we can observe through the technological analysis of these lithic collections the great conceptual complexity depending on the needs to be fulfilled. Raw material quality allowing, the state-of-the-art technology of knapping can be applied to the quartz and, therefore, we should not understand its use as a consequence of environmental constrictions but rather as a result of the variability of the procurement strategies and management of lithic resources among the prehistoric communities.     

Le bassin de l’homme du Pléistocène supérieur de Liujiang, Sud de la Chine : taille du corps, forme du corps et encéphalisation

The Late Pleistocene hominin fossil assemblage from Liujiang, South China include a fairly well-preserved cranium, a right os coxa, a complete sacrum, and other postcranial elements all belonging to a single individual. This rare discovery offers us a unique and singular opportunity in understanding this Late Pleistocene hominin's body proportion and relative cranial capacity (encephalization quotient [EQ]), and also pelvic morphology. Using the available right innominate and its mirror-imaged left side, we reconstruct Liujiang hominin's pelvis. Our analysis of the pelvis indicates that the Liujiang hominin has a very gracile and modern-like pelvic morphology. Indeed, all of the pelvic dimensions are smaller than those of other Pleistocene hominins. Moreover, the pelvic characteristics typical of Middle and Late Pleistocene hominins including Neanderthals cannot be identified in the Liujiang pelvis. In contrast, both Liujiang's metric and non-metric features indicate affinities to more recent human populations including our modern Chinese collections from Guangxi of south China. Further support of this assessment comes from the EQ value of 5.754 for Liujiang which is closer to Minatogawa 2 and modern Chinese populations than to Middle and Late Pleistocene fossil hominins. Our analysis of body shape shows that Liujiang has body proportion (i.e. body height relative to body breadth) typical of warm-adapted populations. Based on these findings, we reason that the modern physical characteristics of Liujiang may allude to a more recent geological age. Alternatively, its morphological “modernity” could also point to a much higher degree of skeletal variation within Late Pleistocene hominins in East Asia.     

Nouvelles observations sur les Miogypsinidés du Miocène inférieur et moyen de Provence et de Corse (France) et de Sardaigne septentrionale (Italie)

The detailed study of the Miocene strata of Bonifacio has revealed an atypical Miogypsinid assemblage. In addition to the three already cited genera, Miogypsinoides, Miogypsina and Miolepidocyclina from this region, Miogypsinodella is for the first time represented by two new species (Mdella corsicana nov. sp. et Mdella pillaria nov.sp.). The stratigraphical ranges of each genus in the Miogypsinidae are not verified here. However, Mdes bantamensis is still present in the Upper Burdigalian and the genus Miogypsinoides is also present in the Lower Langhian. Six species of Miogypsina coexist in the Upper Burdigalian (M. tani, M. globulina, M. intermedia, M. cf. sabahensis, M. cushmani, M. mediterranea) and two species are present in the Lower Langhian (M. antillea, M. digitata). This distribution is apparently an example of palaeoendemism resulting from the geographic isolation and the rotation of the Corso-Sardinian block and also from the palaeogeographical and palaeoecological favourable environment during that time.