Goniatites et conodontes du Viséen/Serpukhovien dans les Pyrénées centrales et occidentales, France

Cephalopods and conodonts from the upper part of the Aspe-Brousset Limestones and lower part of the Iraty Limestones in Central and Western Pyrenees are described. Two levels differing in age are distinguished on their behalf. The oldest one belonging to the Late Visean or Early Serpukhovian yields specimens described as Goniatites baylei Leymerie, 1957, by Mirouse (1957, 1962). They are placed here in the species Dombarites falcatoides Ruzhentsev and Bogoslovkaya, 1971 for which the new subspecies D. falcatoides mirousei is established. The upper level corresponds to the Albergian (upper Serpukhovian) and is characterized by Proshumardites delepinei Schindewolf, 1939. Numerous conodonts belonging to the Lochriea and the Gnathodus groups occur together with this fauna. The joint study of goniatites and conodonts allows us to show the relationship existing between the distributions of both these two groups of organisms as well as to provide precisions on the stratigraphic and the palaeogeographical data in these areas.     

Contacts, blocages et filiations entre les aires culturelles mésolithiques et néolithiques en Europe atlantique

An examination of lithic industries evolution during VI millenium cal BC shows us transformations of mesolithic technical systems under neolithic pressures, with regional variations. Contrasting classical views, mesolithic groups seems to be less active on atlantic façade than similar groups of France or Spain. This technology transfers are not peripheral phenomenons but testify to intense interactions between mesolithic and neolithic communities, especially on weapons.     

Mégalithes et sociétés préhistoriques : concepts et terminologie

The restitution of the megalith’s technical manufacture, whith their assemblies lines and their sequences, enlarges the coast of the sens incluse in each Corsican monoliths. From the megalithics sites of Poghjaredda of Monte Rotondu (Sotta), Ciutulaghja (Appietu), and Presa (Altaghjè), some specifics activities area (pastoralism for example) or activities structured in the space (villages and tombs of middle Neolithic) interest this study. The contributions of many sciences permit to give an economic and social dimension to the choice of megalithics sites. Then, those choices are an aspect of the Neolithic process in Corsica, making part of sculpture and architecture. This study is conclued by a consideration on the actual worked stones’ terminology.     

Donńees morphologiques, histochimiques et microanalytiques sur l'élaboration du tube organominéral d'Alvinella pompejana, Polychète des sources hydrothermales, et leurs implications Phylogénétiques

Vovelle, J. & Gaill, F. 1986. Données morphologiques, histochimiques et microanalytiques sur l'élaboration du tube organominéral d' Alvinella pompejana , Polychète des sources hydrothermales, et leurs implications Phylogénétiques. [Morphological, histochemical and microanalytical data on the elaboration of the organomineral tube of Alvinella pompejana , a polychaete from hydrothermal vents, and its phylogenetic implications.]
The material elaborated by Alvinellu pompejuna Desbruyères & Laubier, 1980, a polychaete worm from hydrothermal vents in the East Pacific, to build up its tube originates from an anterior ventral 'glandular shield'. Mucocytes rich in sulphated glycosaminoglycan provide an accessory component, but the bulk is formed from homogeneous granules, secreted by the deep 'main' cells of this shield. The organic part of the granules, as demonstrated by histochemistry, is proteinaceous, while the mineral part, as proved by microanalysis, includes phosphorus, calcium, iron and in smaller amounts magnesium and zinc. The material of the tube shows an increase in the ratio iron-calcium. Phosphorus may be bound to the organic part, but there is no sulphur present in it. In the laminated tube, scanning electron microscopy and microanalysis detect an enrichment in heterogeneous components of different constitution (balls and crystals). Silica, pointed out as characteristic of fossil worm tubes but absent in secretions, is not of endogenous origin. The original composition of the Alvinella tube can thus be related to that of other examples of the order Terebellida who live in a less drastic environment.     

Ultrastructure de la spermiogenèse et du spermatozoïde de Loimosina wikoni et affinités phylétiques des Loimoidae (Plathelminthes, Monogenea, Monopisthocotylea)

In Loimosina, during spermiogenesis, the zone of differentiation of the spermatid contains two centrioles continued as two 9 +‘1’axonemes. One of the axonemes lengthens and will become the principal axoneme of the spermatozoon. The other axoneme is as long as the first one at the beginning of spermiogenesis, but is shorter in the mature sperm cell. The spermatozoon consists of several regions: (a) at the anterior end, the centriolar derivative of the principal axoneme; (b) a short region which shows cortical microtubules coinciding with external ornamentations; (c) a long uniflagellate region, with mitochondrion; (d) a biflagellate region containing the anterior slender part of the nucleus; (e) the posterior part of the nucleus, with no accompanying cytoplasmic organelles. Spermiogenesis and sperm structure in Loimosina differ from what is known in all other described monogeneans, excepting the monocotylid Heterocofyle to which they show close resemblances. However, the alteration of the second axoneme is more complete in Heterocofyle than in Loimosina. Comparative study of spermiogenesis and sperm ultrastructure thus shows an interesting coincidence with classical phylogenies of the monogeneans, in which the families Loimoidae and Monocotylidae are closely related. Chez Loimosina, pendant la spermiogenèse, la zone de différenciation de la spermatide contient deux centrioles prolongés par deux axonemes de type 9 +‘1′. L'un des axonemes s'allonge et deviendra l'axonème principal du spermatozoïde mûr. Le deuxième axontme est aussi long que le premier au début de la spermiogenèse, mais il est plus court dans le spermatozoïde mûr. Le spermatozoïde comprend: (a) à l'avant, le dérivé centriolaire de l'axonème principal; (b) une courte région contenant quelques microtubules corticaw longitudinaux coincidant avec des omementations extramembranaires; (c) une longue région miflagellée avec mitochondrie; (d) une région biflagellée contenant La partie antérieure effilée du noyau; (e) la région postérieure du noyau, sans organites cytoplasmiques accompagnateurs. La spermiogenèse et la structure du spermatozoïde de Loimosina sont différentes de ce qui est connu chez tous les autres Monogènes décrits, excepté le Monocotylidae Heterocofyle auquel elles ressemblent beaucoup. Toutefois, l'altération du deuxième axonème est moins complète chez Loimosina que chez Heterocotyle. L'étude comparée des spermatozoïdes et des spermiogenèses montre une bonne coincidence avec les phylogenèses classiques, dans lesquelles les familles Loimoidae et Monocotylidae sont proches.     

Lithostratigraphie et biostratigraphie des formations paléocènes et éocènes entre Bayonne et Pau (SW France)

The lithostratigraphy and biostratigraphy of the Paleocene and Eocene formations have been reconsidered on the basis of 18 dated boreholes that intersect the Basque Country, Peyrehorade, Sainte-Suzanne and Sauvelade allochthonous tectonic units, as well as the autochthonous units of the Pey-Saint-Lon anticline, the Arzacq Basin and the North Pyrenean Trough. Correlation of the formations identified in the boreholes and at outcrop has made it possible to outline the sedimentary evolution of this region during the Early Paleogene and to date the various stages of Pyrenean compression on the basis of sedimentary gaps and syntectonic detrital input. The Lasseube Formation is present over the entire study area. Sedimentation becomes differentiated during the Late Selandian-Early Ypresian period. In the North Pyrenean Trough and in the Peyrehorade, Sainte-Suzanne and Sauvelade units, the detrital-clayey Pont-Labau Formation is well developed and all its members are represented (Guillempau, Latapy, Néez, Libaros and Artigueloutan; zones upper P 3b-P 6b; upper NP 5-NP 11). A sedimentary gap showing erosion, and involving zones upper P 3b-upper P 4a and upper NP 5-NP 7, characterises the Basque units, the Pey-Saint-Lon anticline and the western part of the Arzacq Basin. Sedimentation recommences in zone P 8 with middle-bathyal deposits of the Cassoua Member and then continues with the Artigueloutan Member (transition facies towards the Louts Formation) or limestone resembling that of the Meilhan Formation. The Gan Formation shows an east-west polarity. In the east, between the Sainte-Suzanne Unit and the North Pyrenean Trough, the formation is argillaceous with a dominant neritic character, apart from a circalittoral to epibathyal passage in its lower part (zone P 7) containing numerous planktonic foraminifera. The formation is of a detrital and carbonate nature in the west (Sainte-Marie-de-Gosse 1). The bathyal Donzacq Formation appears to transgress a previously deformed surface. Two domains existed during the Lutetian: a continental to neritic domain in the south and a bathyal domain in the north (the Saint-Geours-d'Auribat and Miretrain formations) separated by a variably thick transition zone that is affected by thrust fronts. Two new formations - the Orthez and Sorde-l'Abbaye formations - are proposed, and the Marly limestone formation of Saint-Barthélémy (Douvillé, 1905) is redefined. The Orthez Formation (Sauvelade Unit) is composed of marl and continental conglomerate with neritic carbonate interbedding and belongs to the sub-zones NP 15a and b. The Sorde-l'Abbaye Formation (Peyrehorade Unit and the Basque units p. p.) is composed of neritic carbonate sediments (Lutetian-Priabonian). The Saint-Barthélémy Formation is made up of syntectonic conglomerate, turbiditic limestone and pelagic marl in the central part of the Basque units (NP 15a-NP 16). The Bartonian and Priabonian stages are characterised by carbonate sediments in the Arzacq Basin (Siest Formation). Its base is diachronous: Upper Lutetian (zone SB 16) in the east and Late Bartonian grading to Priabonian in the west (zones SB 17/18 and SB 19). The sediments are argillaceous (Côte des Basques Formation) along the Atlantic coast, in the central part of the Basque units and in the Bayonne-Cauneille syncline. Major thickness variations reflect tectonic phases at the top of the Lasseube Formation in the north (erosion pre NP 8), the Néez Member (NP 7/NP 8 boundary), the Artigueloutan Member (NP 11/NP 12 boundary), and the Gan Formation (P 8/P 9 boundary). The syntectonic conglomerate and breccia indicate the development of thrust fronts in the Libaros Member (NP 8), at the base of the Pillardou and Artigueloutan members (NP 9b, c-NP 10), in the Saint-Geours-d'Auribat Formation (NP 14b) and in the Orthez and Saint-Barthélémy formations (between zones NP 15a and NP 16).     

Ostracodes et stratigraphie du néogène et du quaternaire méditerranéens

A stratigraphical chart of marine ostracoda from Lower Miocene to Recent is established. Selected species (approximatively 220) are those morphologicaly well characterized and known from different parts of the Mediterranean area. It appears that: • lower Miocene ostracodes are still poorly known; • specific diversity is high during the Tortonian and the Lower Messinian before the complete disappearance of marine Mediterranean species during the Upper Messinian évaporitic episodes; • during the early Pliocene, about half of the Upper Miocene marine species are reintroduced with the Atlantic waters; other species migrate for the first time in the Mediterranean Sea by the same way; • at the end of the Pliocene or at the beginning of the Pleistocene several species known in Mediterranean since the Middle Miocene or before, such as Cytherella sp. gr. transversa and Ruggieria tetraptera, as well some “nordic guests” such as Hemicythere villosa and Cythere lutea, appear. This work is an opportunity to confirme a Late Miocene age for the Neogene of Skyros (Aegean Sea), to assign the “Upper Pliocene” of Terquem to the Lower Pleistocene and to refute the existence of a pliocene psychrosphere.     

Corrélation des successions de l'Albien par les ammonites entre la Province Nord-Pacifique et les Provinces européenne et arctique du Domaine boréal : zonation, eustatisme et paléobiogéographie

The vertical distribution of Albian ammonites of the North Pacific Province is described on the basis of several sections located in Northern California. Nine Albian ammonite assemblages are identified, compared to the 4 previously described by Murphy in 1956. Owing to several gaps of observation possibly more assemblages could exist. In the North California Albian history, the first results show a succession of confinement periods - with numerous endemic faunas - followed by periods of open communications with other faunal provinces. As an example, the base of the Middle Albian is marked by exotic ammonites coming from the Tethyan realm (Oxytropidoceras, Lyelliceras) and from the Arctic Province of the Boreal realm (Gastroplites, Pseudopulchellia). These ammonites - except Oxytropidoceras - were not known in that area and are described relatively to their palaeobiogeographical interest. Although rare these migrant faunas give valuable elements to correlate these various provinces. Planktonic foraminifera confirm the existence of open sea communications during the uppermost Albian.With such faunal links, a comparison is proposed between the Albian ammonite zonation of Northern California and the standard and phyletic ones of Europe. This attempt suggests that the major connections between the three faunal provinces are established at second order peak transgressions in the Early and Middle Albian, and during the sea-level high of the Late Albian transgressive period. So, it seems that the vertical distribution of Albian non-endemic ammonites of North California and Europe is largely controlled by global eustatic events. Two palaeobiogeographic maps for Early and Middle Albian and one map for the late Late Albian show the migration outer of these exotic ammonites.     

Phénomènes Périodiques, Métaboliques et Structuraux Chez un Protiste, Euglena gracilis

RESUME. Des divisions synchrones chez Euglena gracilis Z peuvent ětre obtenues par différentes méthodes. Lorsque les cellules sont cultivées sur milieu contenant du lactate comme seule source de carbone, des divisions synchrones sont observables, indépen-damment des conditions d'éclairement. Toutefois, il existe une relation entre la phase des divisions cellulaires et les périodes lumière-obscurité appliquée à la culture. Pendant le cycle cellulaire, nous montrons que les synthèses des macromolécules sont discontinues: c'est le cas pour les ADN nucléaire et mitochondrial, les ARN ribosomaux et non-ribosomaux, ainsi que pour certaines protéines (cytochrome c 558). Des variations cycliques touchant la morphologie des mitochondries et des chloroplastes sont observées. Au cours du cycle cellulaire, les processus métaboliques séquentiels accompagnent les modifications de structure des organites. C'est ainsi qu'en début du cycle, au commencement de la phase G₁, sont synthétisés les ribosomes cytoplasmiques et qu'ensuite, chez les euglènes vertes, les ARN non-ribosomaux sont formés. Ces synthèses d'ARN précèdent l'accroissement du chondriome et du plastidome dans la cellule. En milieu de phase G₁, une nouvelle synthèse d'ARN non-ribosomal commence et est observée avant la synthèse des ADN nucléaire et mitochondrial. En fin de phase G₁, démarre la division des organites à partir du chondriome et du plastidome en réseau. SYNOPSIS. Synchronous divisions of Euglena gracilis strain Z can be obtained by various methods. When the cells are cultivated in a medium containing lactate as the sole carbon source, synchronous divisions are observed, independent of the conditions of illumination. Nevertheless, there exists a relationship between the phase of cell division and the periods of light and darkness applied to the culture. During the cell cycle, the synthesis of macromolecules is discontinuous—this is true of nuclear and mitochondrial DNA, ribosomal and nonribosomal RNA, and certain proteins (cytochrome c 558). Cyclic variations in the structure of mitochondria and chloroplasts are also observed. In the course of the cell cycle, sequential metabolic processes accompany structural modifications of the organelles. Also, at the beginning of the cycle, at the start of phase G₁, the cytoplasmic ribosomes are synthesized, and then, in green euglenids, nonribosomal RNAs are formed. These syntheses of RNA precede enlargement of the chondriome and plastids. In mid-G₁ phase, a new synthesis of RNA begins, which precedes synthesis of nuclear and mitochondrial DNA. At the end of G₁ phase, division of organelles starts, beginning with the chondriome and plastids, arranged in a network.     

Biostratigraphie,paléoécologie et zones d’acmé des foraminifères planctoniques au passage Crétacé-Paléogène dans la Téthys (Tunisie et Espagne) et l’Atlantique (France)

Biostratigraphical high-resolution analyses and quantitative data confirm that deposition is continuous across the K-Pg transition in several sections in Tunisia (El Kef, stratotype section) and Spain (Agost and Caravaca sections) located in the Tethyan realm and the Bidart sections in the Atlantic realm, without any relevant hiatus. The Upper Maastrichtian assemblages of planktic foraminifera from these sections are largely dominated by small biserial heterohelicids. They are associated to common species having planispiral test (i.e. globigerinelloids), trochospiral test (i.e. hedbergellids, rugoglobigerinids globotruncanids), to rare triserial heterohelicids (i.e. guembelitriids) and trochospiral species showing tubulospines (i.e. schackoinids). Stratigraphical ranges of these diverse taxa through the late Maastrichtian in the Tethyan and Atlantic realms show very few changes in the planktonic foraminiferal assemblages and most of the species are present in the Abathomphalus mayaroensis biozone. By our high-resolution sampling and the intensive research for the A. mayaroensis index species in the uppermost Maastrichtian samples, we confirm that this species is omnipresent up to the top of the Maastrichtian. Therefore, A. mayaroensis is present in almost all samples which are late Maastrichtian in age, but this species became very scarce in the uppermost Maastrichtian samples. This scarceness could be due to a climate cooling. A sharp decrease in relative abundance of the deep dwellers species, like as Abathomphalus intermedius and A. mayaroensis as well as in other keeled globotruncanids is observed at the studied sections from the Tethyan realm (indicative of low latitude) across the latest Maastrichtian. At the K/Pg boundary, all the globotruncanids disappeared. They are considered specialists living in tropical-subtropical deep seawater habitat. At this boundary, large and ornate heterohelicids also disappeared. Therefore, all the studied sections show that about 90 % of the Maastrichtian species became extinct according to a catastrophic mass extinction pattern. Only about 10 % crossed the K/Pg boundary and survived during the earliest Danian. The minor difference in the number of disappeared taxa is related to their latitude location or environment paleodepth. The changes in the species relative abundance, observed in the successive planktic foraminiferal assemblages, make it possible to recognize the Acme-stage 0 typical of the upper Maastrichtian interval. It is characterized by the highest species richness of Globotruncanids and heterohelicids specialists of tropical to subtropical marine conditions, the Acme-stage 1 typical of the Guembelitria cretacea Zone, and in particular of the Hedbergella holmdelensis Subzone dominated by “opportunists” species belonging to Guembelitria, the Acme-stage 2 which corresponds to the Pv. eugubina Zone dominated mainly by specimens belonging to Palaeoglobigerina and Parvularugoglobigerina and the Acme-stage 3 which characterizes mainly the Ps. pseudobulloides Zone dominated by biserial species belonging to Chiloguembelina and Woodringina.     

Sur les familles des Helicancylidae Hyatt, 1894 et des Acrioceratidae Vermeulen, 2004 ; réponses et précisions apportées au travail de Bert, 2009

This work is mainly an answer to the work of Bert (2009), on families Helicancylidae Hyatt, 1894 and Acrioceratidae Vermeulen, 2009. On the nomenclatural speaking, the non validity of the genus Helicancylus Gabb, 1869 and of the family Helicancylidae Hyatt, 1894 and, consequently, the validity of the family Acrioceratidae Vermeulen, 2004 are established. The second part of this work is devoted to the respect of former work and, contrary to the assertions from Bert (2009), it is shown that the stratigraphical positioning of the Upper Barremian level with small Barremites, realized by Cotillon (1971), is at least as precise as that proposed by Bert. The last part of this work highlights a lack of bibliographical references, fact which had already been highlighted ( Vermeulen and Lepinay, 2010) in a former work of Bert et al. (2009).