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.     

Le Campanien-Maastrichtien du bassin des Aurès,Algérie : biostratigraphie,paléoenvironnements et leurs implications

An integrated study of the lithological, micropaleontoligical, sedimentological and statistical data has been done on samples taken from four geological sections (El Gaaga, Tighanimine and El Kantara) spread in different sea areas. This allowed to redefine the stratigraphy of the studied area to provide information about the benefits of some kinds of foraminifera, planktonic and ostracods in knowing the palaeoenvironment and identifying the types referring to the latter during the late cretaceous. The late creataceous appeared in Aures in a form of two hills separated by a light lowness. This morphology corresponds generally to the tripartite composition of the Campanian-Manstrichtian with lower member of limestone-marl (Haraoua Member), a median marl member (Akhdar Member) and an upper member of massive limestones (Ncham member). The regularity of this trilogy changed in the anticline of Dj. El Azereg through a reduction, visibly affecting the tree members. The study of the foraminifera in the late cretaceous (Campanian-Manstrichtian) in the Aures proved the existence of 141 species (48 planktonic and 93 benthic foraminifera). Applying the concepts of biostratigraphy mainly on the foraminifera allowed to distinguish different bizones, ranging from lower Campanian of El Gaaga and El Kantara cuts (Globotruncanita elevata biozone) and Maastrichtian (Contusotruncana contusa biozone). The biostratigraphical framework is thus relatively precise and helps precising for instance the position of some inconsistent boundaries.     

Un nouveau gisement miocène à ichthyofaune au sud de la chaîne des Chotts (Tunisie méridionale). Paléoenvironnement et paléobiogéographie

A new fish-bearing Miocene site, south of the ‘Chaîne des Chotts’ (southern Tunisia). Palaeoenvironment and palaeobiogeography. A systematic excavation in the Miocene continental sands of the Béglia Formation (southwestern Tunisia), south of the ‘Chaîne des Chotts’, yielded a rich fossil-fish assemblage. These sands, with soft rollers and oblique stratifications are in unconformity on the Cretaceous and are covered by Miocene clays. The organisation and the nature of the facies, as well as the palaeocurrent figures testify to a proximal fluvial-deltaic regime. It is SW–NE prograding. The three fish taxa (polypterid, clariid, latid) are typical of modern Nilo-Sudanese assemblages, but are absent from Maghreb. The regional palaeobiogeographic relations are discussed. To cite this article: B. Mannaï-Tayech, O. Otero, C. R. Palevol 4 (2005).     

L'évolution des gastéropodes lacustres et la paléoéologie des diatomées dans le Néogène de Kos (Dodécanèse,Grèce)

Evolutionary lineages of several limnic gastropod genera (Viviparus, Melanopsis, Theodoxus) from the Neogene of Kos island (Dodecanese, Greece) are described and interpreted. The attempt is made to analyse the paleoecological development of a limnic sedimentary basin in the eastern portion of Kos by means of Diatoms. Obviously, there is no relation between the chemical parameters of the water of the former lake and the morphological development of the gastropods. The lineages of Viviparus brevis, Theodoxus doricus and Melanopsis gorceixi are suggested to be caused by phyletic transformations and not by changing environmental conditions. It is, thus, possible to establish a local biostratigraphy based on subspecies, and moreover, a more regional one based on longer ranging species.     

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.     

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.     

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.     

Le Plio-Pléistocène de Camerota(Italie méridionale): Géomorphologie et Paléoflores

Geomorphological investigations have been carried out in Camerota surroundings where marine microfaunas have been discovered. So, we can separate the Late Pliocene deposits from Calabrian and post-Calabrian levels. Preliminary palynological results show a vegetational evolution in relation with the climate. Leaf-remains give informations on the structure of the vegetation.     

Recherches expérimentales sur l'action des rickettsies des invertébrés sur les vertébrés: Étude de l'infection nasale et buccale chez la souris parRickettsiella grylli

Résumé Une rickettsie entomopathogène:Rickettsiella grylli proche des chlamydies par son cycle de multiplication est introduite chez la souris par voie nasale et par voie buccale. La rickettsiose expérimentale produite est étudiée sous les aspects clinique, anatomopathologique, sérologique et histologique. Les rickettsies sont recherchées dans les tissus par immunofluorescence et microscopie électronique. Chez les souris infestées par voie nasale, les rickettsies restent localisées dans les poumons. Lors des contaminations fortes, ces derniers subissent une hépatisation et une bronchopneumopathie se développe; cette pneumopathie se maintient pendant eviron 2 mois puis évolue, dans de nombreux cas en une bronchopneumopathie chronique durant plus d'un an. Les souris élaborent des anticorps agglutinants spécifiques dont le taux est proportionnel à l'atteinte pulmonaire. L'infestation par voie buccale ne détermine aucun effect pathologique à court ou long terme.

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Summary Rickettsiella grylli Vago & Martoja is a rickettsial entomopathogen close to the chlamydia by its multiplication cycle. This organism has been inoculated in mice by intranasal and oral routes. The experimental rickettsiosis has been studied by the clinical syndromes, anatomopathology, serology, histology, immunofluorescence and electronic microscopy. By inhalationR. grylli is localized in lung tissues. In heavy contaminations the lungs present hepatisation and a bronchopneumopathy that last 2 months and evolves to a chronic bronchopneumopathy in 50 % of the tested mice. Agglutinin type antibodies are produced and their concentration are proportional to the severity of the lung infection. No short term or long term pathological effects are detected by oral administration.

     

Découverte de vertébrés aquatiques présumés paléocènes dans les Andes septentrionales de Bolivie (Rio Suches,synclinorium de Putina)

The teleost fish Brychaetus and a dyrosaurid crocodilewere recognized among the aquatic vertebrates recently discovered in the northern area of the Titicaca lake (Bolivia). These fossils allow the presumption of a Paleocene age for the vertebrate bearing formation. The structural interpretation of this chronological data is discussed.     

Un complément à l'appareil séricigène des Uloboridae (Araneae): Le paracribellum et ses glandes

Summary In several genera of Uloborid spiders the median spinnerets are provided with a cluster of specialized spools. These spools are comparable in structure with those of the cribellum, but far fewer in number. We name the newly described formation of spools the paracribellum. The histological features of the associated glands are similar to those of the cribellar glands; histochemically they seem closer to the pseudoflagelliform glands. It is suggested that paracribellar fibers impart consistency to the fibrillar secretion of the cribellum.     

Le phénomène de superparasitisme chez les parasites oophages des punaises des blés

Résumé L'étude du superparasitisme chez les parasites oophages desAelia a été réalisée avec 3 espèces d'Ooencyrtus: O. fecundus Ferr. & Voeg.,O. nigerrimus Ferr. & Voeg., etO. telenomicida Vass. Ces 3 espèces apparaissent comme ayant un pouvoir de discrimination leur permettant d'éviter le superparasitisme lorsqu'elles ont suffisamment d'h?tes à leur disposition. Dans le cas contraire ou lorsque le nombre de femelles dans un même tube de ponte s'accro?t, la tendance au superparasitisme augmente. Le superparasitisme se traduit par une baisse de la fécondité, une diminution de la taille et une modification du taux sexuel de la descendance.

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Summary The study of superparasitism in the oophagous parasites of theAelia spp has been realized with 3Ooencyrtus species:O. fecundus Ferr. & Voeg.,O. nigerrimus Ferr. & Voeg. andO. telenomicida Vass. These 3 species appeared to have a discriminating ability which enable them to avoid superparasitism when the host population at their disposal is sufficient. In the opposite case or, when the number of females increases in the same tube, superparasitism tends to increase. Superparasitism results in a decrease in fecundity as well as in size and the sex-ratio of the offspring.

     

Flore du Jurassique basal de la ville de Mende (Lozère) : synthèse des gisements historiques,nouvelles données sédimentologiques,paléontologiques et paléoenvironnementales

During the 20th century, because of urbanization, most palaeontological sites yielding plants (Hettangian–Sinemurian in age) from the city of Mende have disappeared, or they have been forgotten. This article presents a synthesis of sites yielding plants, from their discoveries in the 19th century to recent prospecting. New lithostratigraphic and palaeobotanical data are brought for two historic sites (Ravin del Pouset and Petit Séminaire), as well as two new localities (Causse d’Auge road and Gardès road). This study reveals the diversity of plant-containing lithofacies (dolomudstone, marl, limestone/calcarenite and oo-bioclastic limestone) and the diversity of plant preservations (charcoalified compressions with or without cuticle, isolated cuticle, external casts/impressions). Microfaciological study of plant beds demonstrates the diversity of depositional environments. Protected, restricted and shallow environments with low wave exposure and probable euryhaline conditions are clearly the most favourable to the accumulation and the preservation of fossil plants. These early Liassic palaeofloras, among the southernmost yet reported for Laurasia, are of significance for the plant geography and global paleoecology at that time.     

Les ostracodes et foraminifères associés des dépôts de l’Éocène moyen et supérieur de la coupe de Jebel Serj (Tunisie centrale). Intérêt biostratigraphique,paléoécologique et paléobiogéographique

The ostracod fauna collected from the Cherahil formation that crops out at the Jebel Serj section (central Tunisia) contains 24 species belonging to 12 genera. These ostracods are associated with 9 genera of benthic Foraminifera (including 4 Nummulites species) and 7 genera of planktonic Foraminifera. The biostratigraphic study of ostracod assemblages results to the recognition of 6 biozones which are correlated with Lutetian-Priabonian. The Shannon Weaver, Margalef and equitability indices point to internal platform netritic conditions, with minor fluctuations in depth and oxygenation. The palaeobiogeographic distribution of ostracod species found in the study area of Central of Tunisia establishes a good connexion with the basins developed in Northern Africa (Tunisia, Algeria, Libya and Mauritania) and the Middle East (Egypt and Jordan).     

Caractères physico-chimiques des choanoleucocytes de quelques Invertébrés

Sans résumé