Découverte de Foraminifères planctoniques paléocènes dans les brèches,précédemment tenues pour aptiennes et d'origine diapirique,des Pyrénées basco-béarnaises

After the dating, by means of planktonic Foraminifera, of post-metamorphic marine breccias, Upper Danian–Lower Selandian in age, associated to hemipelagites and unconformably overlying the Cretaceous tectogenic axis of the Pyrenees from Roussillon to Bigorre, was it possible to extend westwards the breccia-filled Palaeocene ‘trough’ as far as the ‘Zone des Chaı̂nons béarnais’? This later unit, which belonged to the North-Iberian palaeomargin during Lower Cretaceous, was previously considered by several authors as characterized by an important halokinesis generating, during Aptian/?Albian, collapses of the Jurassic–Lower Cretaceous carbonate cover above dissolved salt domes and spectacular accumulations of breccias. In fact, we have everywhere identified Palaeocene planktonic microfauna within the matrix of these breccias (and within the associated hemipelagites), particularly of the reference ‘diapiric’ breccias of Etchebar, Lauriolle, Layens and Bosmendiette/Beloscare. Deposited into intra- ‘trough’ sub-marine canyons, after karstification and erosion of intermediate mountains with a steep topography previously induced by Uppermost Cretaceous compressions, the herein studied Palaeocene marine breccias should not be hereafter regarded as linked to any Lower Cretaceous diapirism on the North-Iberian palaeomargin. To cite this article: B. Peybernès et al., C. R. Palevol 1 (2002) 3–10.     

Découverte d'une faune de vertébrés dans l'Oligocène inférieur de Vayres-sur-Essonne (bassin de Paris,France) : biodiversité et paléoenvironnement

The new rich vertebrates deposit from the Lower Oligocene, at Vayres-sur-Essonne (Essonne, France), contains 34 marine and seven continental taxa, 17 taxa being recorded for the first time from the Paris Basin. The richness of the ichtyofauna is higher than in anyone of the Parisian Oligocene deposits and equals the one of the ‘Argiles de Boom’ (Belgian Rupelian). Its affinities with the septentrional ichtyofauna is confirmed, meridional elements being rare. The terrestrial fauna, the oldest known from stratotypical Stampian (base of the Upper Stampian) shares affinities with the one of Montalbán and attests the occurrence of nearly freshwater environments. To cite this article: D. Merle et al., C. R. Palevol 1 (2002) 111–116.     

Nouveaux sites à vertébrés paléogènes dans la région des Gour Lazib (Sahara nord-occidental,Algérie)

Recent fieldworks in the Palaeogene of the Gour Lazib area (Hammada du Dra, Algeria) led us to reassess the stratigraphic allocations of the Glib Zegdou formation and to complement the lithostratigraphy of this formation. This continental series unconformably overlies a Palaeozoic substratum. The prospecting–exploration works in the middle member of the formation allowed us to discover several new vertebrate sites (with lungfish, actinopterygians, chelonians, and notably mammals), associated with Early to Middle Eocene charophyte oogones. We describe a hyracoid (Titanohyrax tantulus) and a macroscelidid (?Chambius sp.). We here also report the discovery of two rich mammalian sites.     

Sur les bois fossiles du paléocène de sessao (Niger)

In this article three structures discovered in the Palaeocene marine beds of the Krebb de Sessao (southern part of Niger) are described. These beds havevalso yielded remains of vertebrates. The formation in which these fossils were found corresponds to a marine regression; it suggests that the sea was shallow and extended rather far to the east beyond the Krebb de Sessao. A tentative synthesis presented at the end of this work seems to indicate that the types of dicotyledon wood structure of the Upper Cretaceous and the Palaeocene, at least those described from Africa, differ from the types known from more recent levels.     

Le bassin lacustre miocène de Bes-Konak (anatolie-turquie): Géologie et introduction a la paléontologie des vertébrés

The tertiary lacustrine and marshy facies ofBes-Konak (Ankara-district) has provided a rich fauna of Vertebrates preserved as molds and casts in Diatomites and volcano-sedimentary beds.In this assemblage are: Cyprinid fishes (Leuciscus(P.) etiliusRückert Ulkümen) with among them a new species of Barbus, some Amphibians both Urodela (mature Triturinae) and Anura (larval forms of Pelobates sp. and mature Rana sp.), a Turtle (Chelydridae-Chelydropsis sp.) a Snake (Colubroïde-Colubridae or Viperidae) and Birds (among them a new species of cormorant).According to the others various data resulting from palaebotanical, palynological and structural investigations, this fauna is clearly suggestive of a lower or middle Miocene deposit. It supports readily the climatic features (local sub-tropical microclimate inside a regional hot-temperate context) as invertebrates, macro and microflora and sedimentology had already shown.Once more, it points out the peculiar trophic type of the limnic area of Bes-Konak and its evolution to a well-marked eutrophic condition.     

Les premiers vertébrés et les premières étapes de l’évolution du crâne

The earliest vertebrates and the first steps of the evolution of the skull. Vertebrates are one of the few metazoan taxa, which display a well-corroborated phylogenetic pattern, a good and anatomically informative fossil record, and a relatively slow ontogenetic development. They are thus a favourite taxon for illustrating evolution as a historical process, although the stem of the vertebrate tree remains poorly documented by fossils, except for some Early Cambrian forms. Therefore, the characterization of the vertebrates now rests essentially on a small number of developmental characters, mostly involved in the rise of the skull, and whose precursors may occur in other chordates. The tree of the crown-group vertebrates also shows some major morphological gaps due to early extinctions, but a number of Palaeozoic stem gnathostome taxa helps in documenting the agnathan-gnathostome evolutionary transition. However, stem cyclostomes remain elusive.     

Présence du crocodilienPhosphatosaurus (Mesosuchia,Dyrosauridae) dans le paléocène du niger et du Mali

Jaw fragments of the large dyrosaurid crocodilianPhosphatosaurus Bergounioux, 1955, previously known only from the Lower Eocene of Tunisia, are described from the Lower Palaeocene of Niger and Mali. Teeth described by Gemmellaro from the Maastrichtian of Egypt are also referred to a similar form. Although too incomplete to be specifically identified, all these remains indicate that this group of dyrosaurids with a robust snout and large teeth has differentiated early. The evolution of the genusPhosphatosaurus was marked by an elongation of the mandibular symphysis. Résumé Des restes de mâchoires du grand Crocodilien dyrosauridéPhosphatosaurus Bergounioux, 1955, connu jusqu’ici seulement dans l’Eocène inférieur de Tunisie, sont décrits en provenance du Paléocène inférieur du Niger et du Mali. Des dents du Maestrichtien d’Egypte décrites par Gemmellaro sont aussi rapportées à une forme similaire. Bien que trop incomplets pour être identifiés spécifiquement, tous ces restes montrent que ce groupe de Dyrosauridae à museau robuste et à grosses dents s’est différencié de façon précoce. L’évolution du genrePhosphatosaurus a été marquée par une elongation de la symphyse mandibulaire.     

Les possibilités de l'application des germes pathogènes dans la lutte contre les chenilles défoliatrices

Résumé L'utilisation des germes pathogènes est une solution du problème de la sélectivité. Des solutions concurrentes existent avec certains pesticides chimiques. L'utilisation des germes pathogènes est donc envisagée d'une manière pragmatique en négligeant les problèmes de recherches fondamentales. Pour cette raison les mycoses et les protozoonoses ne sont pas retenues. Les viroses offrent un exemple de la plus grande spécificité d'action. L'application des virus d'insectes a été surtout développée en sylviculture. Une grande difficulté est la multiplication des virus sur organismes vivants. Les bactérioses peuvent être seules retenues pour l'agriculture et l'arboriculture intensives: elles ont un spectre d'action assez étendu mais suffisamment sélectif; les bactéries qui nous intérresent peuvent être multipliées industriellement. Le statut deBacillus thuringiensis Berliner et les propriétés des préparations commerciales ont fait l'objet de développements récents. Dans une revue critique des applications de ces préparations en arboriculture fruitière, on considère d'abord le cas des Mineuses et des Tordeuses. Presque toutes ces chenilles sont susceptibles àB. thuringiensis. Mais la difficulté d'utilisation des préparations est de nature éthologique. De bons résultats sont obtenus au Canada contreArgyrotaenia et en U.R.S.S. contreHyponomcuta. En U.R.S.S. on utilise des produits mixtes à concentration réduite (0,5%) de préparation bactérienne et à concentration extrêmement faible (0,002%) de D.D.T. Les résultats contre le Carpocapse sont négatifs. Les résultats contre les chenilles défoliatrices sont très satisfaisants: en Hollande et au Canada contreMalacosoma; au Canada contre les Géométrides,Operophtera etAlsophila espèces très susceptibles àB. thuringiensis, à la dose de 1 à 2 pounds de préparation (titrant 30×10⁹ spores viables par gramme) pour 100 gallons, soit environ, 1,5%; en France, ces résultats sont confirmés. En conclusion, l'utilisation en verger des prépararations commerciales deBacillus thuringiensis doit être ?intégrée? dans un programme général de protection comprenant à la fois les traitements chimiques et les méthodes culturales. De tels programmes sont actuellement expérimentés dans certains vergers de Pommiers par l'I.P.O. et le T.N.O. en Hollande.     

Nouvelles recherches sur la vitesse des vertébrés,auteurs de traces fossiles

This paper follows up on one published in Geobios1984, on the estimation of the velocity of trackmakers represented by fossil trackways.A simplification of the previously given formulaewill make it easier to calculate estimations of the lengths of «apparent limb, period and velocity of a walking animal. Observations show that the «walking angle decreases with the size of animals (in the case of a slow walk), the diminution being due to the exponential rising of the moment of inertia, a mathematical relation is proposed that links the «walking angle to the length of the radius of gyration i.e. the length of the «apparent limb. This relationship agrees with some datas from ichnology and with observations of living animals. With this equation and others presented here a table has been worked out which gives the estimates of «apparent limb, «walking angle, in terms of stride, estimates comprised in an interval of likelihood given by the coherent different values of the «walking angle. Velocity come from the pendular period. Interpolations from this table permit its utilization so for the values of the stride length distinct that presented.     

Première découverte d’un squelette de Channidae (Poisson téléostéen) dans le Miocène inférieur d’Illerkirchberg, près d’Ulm (Wurtemberg, Allemagne)

A skeleton of a Channid fish is reported for the first time from the European Lower Miocene. Because of the lack of any appropriate diagnostic character, it is nevertheless impossible to determine if it belongs either to the Asiatic genusChanna Scopoli or to the African one,Parachanna Teugels &Daget. For this reason, its palaeobiogeographical significance remains unclear. Otoliths (sagitta) that very likely belong to the same Channid species have been described from Illerkirchberg asChanna elliptica (vonSalis). They are compared to the sagitta from recent species of the generaChanna (Scopoli) andParachanna (Teugels &Daget). Their morphological characters are intermediate between those characterizing the sagitta of both genera.     

Découverte de charophytes et ostracodes de l’Yprésien inférieur dans les Monts des Ksour (Algérie) : biostratigraphie et paléoécologie

A stratigraphic, palaeontological and sedimentological study was carried out in the red beds cropping out on the left side of Oued Tafarahit, south-east of the Ksour Mountains (Algeria). The studied succession consists of a non-marine fining-upward detrital formation, including microconglomerate, sandstone and clay beds, which were previously attributed to the Cenozoic sensu lato, since no palaeontological evidence was available. Sedimentology suggests deposition in a fluvial environment. The clayey levels yielded the assemblage formed by the charophytes Peckichara atlasensis, Maedleriella cristellata, Nitellopsis (Tectochara) thaleri, Grovesichara sp., and Lamprothamnium papulosum and the ostracods Neocyprideis meguerchiensis, Herpetocypris? sp. and Cyprinotus? sp. This assemblage allows constraining the age of the detrital series from Oued Tafarahit to the Ypresian. Ostracods are typical of freshwater to euryhaline environments. The freshwater taxa (Herpetocypris? sp. and Cyprinotus? sp.) would indicate phases of desalinisation during periods of flood. However, the brackish water species (Neocyprideis meguerchiensis) is characteristic of saline phases related to low water table periods. Moreover the charophyte and ostracod assemblage confirms a close palaeobiogeographic relationship between North Africa and Southern Europe during the Lower Eocene.     

Découverte de faunes d'Ammonites de la zone à Platynota(Kimméridgien inférieur) dans les Monts de Chellala (avant-pays Tellien,Algérie); Conséquences stratigraphiques et paléogéographiques

In Chellala mountains (Seba el Abiod), in Western Algeria, new biostratigraphic data, based on Ammonites, allow characterize, for the first time in North Africa, the Platynota zone with the species-index Sutneria platynota. This species was known, to the present time, only in the South European border. These new biostratigraphic data show the diachronism of flyschoid facies. They do not exceed middle Oxfordian in the Tlemcenian zone; on the contrary they go up to lower Kimmeridgian in the preatlasic zone.     

Les vertébrés du Berriasiende Canjuers (Var,France) et leur environnement

The vertebrate fossil locality of Canjuers correspondsto a protected marine environment near an emersive zone, on the shelf of Middle Verdon, in communication with the open sea (toward the North) through channels. The fishes (carnivorous pelagic and planctonivorous pelagic) are the most abundant vertebrates. They were already dead when they reached the depositional area, together with the floated shells of ammonites. The necton, dependent on the bottom for its food and the fixed benthos are nearly absent. The free and sessile benthos, poor in species, shows adaptations to a muddy bottom and rare forms adapted to a hardened bottom. The microfauna is rare. The infauna (essentially horizontal) is present inside the channels. The water temperature, the very low hydrodynamism and the lack of infauna imply difficult conditions on the bottom (micrite beds and laminites in the lower part of the deposit). Tridactyle tracks of vertebrates confirm, on the other hand, the feeble depth of the water. The near supratidal zone was more or less colonised by vegetation and was occupied by a very differentiated reptilian fauna (flying forms, continental running and burrowing forms, swimming forms) corresponding to a continental environment. The biotic and abiotic factors show the occurence of four distinct environments: protected low depth marine, channels, supratidalintertidal and pure marine. The taphonomy corroborates that the deposit was a thanatocoenosis for the marine organisms, except when water movement permitted life.