Sur la présence de Palaeomicrocodium (Algue?, Incertae sedis?) dans le Givétien inférieur de Belgique

Describes the oldest recorded microcodiacean fromthe Early Givetian Alvaux Limestone (Namur Syncline, Belgium). Palaeomicrocodium devonicumMamet & Roux characterizes very shallow water carbonates associated with Sphaerocodium mudmounds. Cenozoic contamination is excluded.     

Sur la morphologie externe et interne de Rotorboides granulosa (Heron-Allen & Earland) emendation du genre Rotorboides Sellier de Civrieux, 1977 (Foraminiferida)

Discorbis valvulata granulosa HERON-ALLEN and EARLAND, which has been found by the present authorsin the recent deposits of Watamu beach (Kenya), is the type-species of the genus RotorboidesSELLIER de CIVRIEUX, 1977. The study of this species has permitted to describe in detail its outer and inner morphology, to discuss its previous assignments (Discorbis, Rotorbinella) and to emend the genus Rotorboides.     

Ancistrine,ancistine, ancistrocladeine trois alcaloides isoles de L'ancistrocladus ealaensis

Ancistrine, ancistine are 2 new alkaloïds isolated from the roots of Ancistrocladus ealaensis. Their structures were determined on the basis of spectral data. Ancistrocladeine is identical with an alkaloïd isolated earlier from Ancistrocladus tectorius.     

Sur la découverte des genres Ischyrhiza et Ptychotrygon (selachii,batomorphii) dans le Crétacé supérieur de Vendée (France)

The genera Ischyrhiza and Ptychotrygon are pointed out for the first time in Upper Cretaceous of France. A new species of Ischyrhiza: I. viaudi is described. These discoveries allow to enlarge considerably the area of dispersion of these genera.     

Mēthylation de dērivēs n-acylēs du 2-amino-2-dēsoxy-D-glucose en prēsence de sels d'argent: observations sur le comportement du groupement ambident acetamido (ou benzamido)

The behavior of the acetamido (and benzamido) ambident, nucleophilic group under methylation with methyl iodide and silver oxide has been studied for several 2-acetamido-2-deoxy-D-glucose derivatives. When silver perchlorate was added, alkylation occurred at the oxygen atom, giving methyl imidates that were labile in acidic medium. Benzyl 2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranoside was converted into N-(benzyl 3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranoside-2-yl) methyl acetimidate (83%), which was subsequently hydrolyzed quantitatively in acidic medium into the corresponding amine salt. Similar results were obtained with benzyl 3,4,6-tri-O-acetyl-2-benzamido-2-deoxy-β-d-glucopyranoside, methyl 2-acetamido-2-deoxy-3,4,6-tri-O-methyl-β-D-glucopyranoside, and benzyl 2-acetamido-3,4,6-tri-O-benzyl-2-deoxy-β-D-glucopyranoside. Under Kuhn's methylation conditions (methyl iodide-silver oxide-N,N-dimethylformamide), alkylation of the just mentioned derivatives occurred at both oxygen and nitrogen atoms.     

Une espèce géante de MuscardinusKaup, 1829(Gliridae,Rodentia, Mammalia) dans le gisement karstique de Cala Es Pou (Miocène supérieur de Minorque,Baléares)

In this paper, Muscardinus cyclopeus nov. sp., from the locality of Cala Es Pou, in Menorca (Balearic Islands)), is described. M. cyclopeus is close to M. viretiHugueney & Mein, but shows a greater size. This species belongs to a new phase of insularity in the Balearic Islands, different from the classical Myotragus-Hypnomys-Nesiotites faunas. This phase may be due to variations in the sea level within the Messinian. Other elements belonging to this phase are: Geochelone gymnesicaBate, cf. Alilepus nov. sp. and Rhinolophus cf. grivensis (Deperet).     

Présence de Chitinozoaires dans le passage Siluro-Dévonien de la Montagne Noire sud-orientale (Hérault,France)

The Silurian-Devonian boundary beds of the southeastern Montagne Noire contain few but well-preserved Chitinozoans. A total of 20 species have been recognized. We distinguish 4 assemblages which characterize the Upper Ludlovian, the Pridolian and the Lochkovian sediments.     

Signification paléoécologique des assemblages de diatomées du Messinien dans le bassin de Melilla-Nador (Rif Nord-Oriental, Maroc)

In the Melilla-Nador basin, the diatomites represent one of the main sedimentary components of the Messinian together with reefal carbonate platforms. Two vertical sections were realised in the diatomitic levels from distal platform. Diatom assemblages are for the first time described in this basin. A total of 125 diatom species were determined: 73 centrics and 52 pennates. Significant diatom assemblages defined from the statistical analysis indicate ecological variations concerning diatomitic levels or parts of diatomitic levels. Using the data sets we propose paleoenvironmental models showing the complexity of the ecological interactions. This study point the permanence of opened marine environment, the impulse of cold waters from Atlantic origin, a general decrease in bathymetry in the Messinian marls-diatomitic series, the influence of the carbonate platform progradation and the occurrence of upwelling systems.     

Putting incertae sedis taxa in their place: a proposal for ten new families and three new genera in Sphaeropleales (Chlorophyceae,Chlorophyta)

Best known for aquatic colonial algae such as Hydrodictyon, Pediastrum, or Scenedesmus, the order Sphaeropleales also contains numerous coccoid taxa from aquatic and terrestrial habitats. Recent findings indicate that coccoid lineages in this order are very diverse genetically and may be the prevalent form, although their diversity is often hidden morphologically. This study characterizes coccoid algae recently discovered from desert soil crusts that share morphological and ecological features with the genera Bracteacoccus, Pseudomuriella, and Chromochloris. Analyses of a multi‐gene data set that includes members from all sphaeroplealean families are used to examine the monophyly of these morphologically similar taxa, which are shown instead to be phylogenetically distinct and very divergent. We propose new generic names for these lineages: Bracteamorpha, Rotundella, and Tumidella. In addition, we propose an updated family‐level taxonomy within Sphaeropleales that includes ten new families of coccoid algae to accommodate the newly presented genera and many incertae sedis taxa in the order: Bracteamorphaceae, Chromochloridaceae, Dictyococcaceae, Dictyochloridaceae, Mychonastaceae, Pseudomuriellaceae, Rotundellaceae, Schizochlamydaceae, Schroederiaceae, and Tumidellaceae.     

The optical brightener Calcofluor White disorders thecal architecture and inhibits cell division ofCryothecomonas longipes Schnepf et Kühn, a marine nanoflagellate incertae sedis

Summary Calcofluor White inhibits the division of the marine nanoflagellateCryothecomonas longipes and causes the development of monstrously lobed cells. It disturbs the assembly of a putative noncellulosic fibrillar polysaccharide in the theca. The compact layer of the theca becomes thicker and wider, less densely packed and less rigid. The deposition of thecal components becomes uncoordinated. In consequence the initially unaffected coat of the theca and loose portions of the compact layer protrude from the cell surface. These are then convoluted, with the coat on their convex faces. The spacing of the coat ridges is increased here. The tension between the different layers obviously stabilizes the theca and contributes to its rigidity and elasticity.Abbreviations CW Calcofluor White - DCB 2-chloro-6-dichlo-robenzonitrile     

Effets d'un régulateur de croissance d'insectes,le fénoxycarbe,sur la diapause du psylle du poirier Cacopsylla pyri

The nature of the responses of the sheep blowfly Lucilia sericata Meigen (Diptera: Calliphoridae) to carrion odours and carbon dioxide were examined in a windtunnel in the laboratory and the attractiveness of carrion-bait was examined in the field. In the wind tunnel, gravid 9-day-old females increased both the number and duration of their flights, in response to carrion odours. In addition, linear velocity was reduced and the sinuosity of flight increased in the presence of these odours. With 3-day-old females, the response to carrrion odour depended on previous exposure to proteinaceous material. Protein deprived females showed kinetic responses to carrionodour which were similar to those of gravid females. No such changes were observed in protein-fed females. No responses to CO₂ were observed. In the field, the importance of olfactory cues in bait location was demonstrated by the absence of L. sericata from sticky targets lacking an odour bait. Increased bait concentration did not affect the age, sex ratio or ratio of L. sericata to other Lucilia spp. caught, but did increase the numbers caught. Analysis of the reproductive status of females caught, indicated that a greater number of gravid females were caught than expected, while a lower number of females in the final stages of vitellogenesis were caught than expected. The results show that the responses of L. sericata to odours are complex, and are dependent on both exogenous and endogenous stimuli, the latter including the stage of ovarian development.     

Le jurassique supérieur et le Crétacé inférieurd'Ankilizato (bassin de Morandava,Madagascar)

Upper Jurassic and Lower Cretaceous from Beritsa, near Ankilizato, are an important landmark between well known cross sections of Northern (Antsalova) and Southern (Sikily) parts of the Morondava Basin. New ammonites and belemnites fauna point out an Upper Jurassic to Upper Valanginian age for this section. A paleogeographical scheme shows the dynamical structure of «Ankilizato gulf at that time.     

Des serpents (Reptilia,Squamata) de type nord-américain dans le Miocène Français. Évolution parallèle ou dispersion?

The French Miocene (Orleanian and Astaracian) yielded five new species of snakes referable to four genera from the Neogene or Recent of North America: Texasophis meini nov. sp., Paleoheterodon arcuatus nov. sp., Neonatrix europaea nov. sp., Neonatrix crassa nov. sp. (Colibridae) and Micrurus gallicus nov. sp. («Elapidae). It is suggested that Micrurus and the previously described boid snake Albaneryx from the French Miocene probably represent lineages that originated in North America and reached Europe by way of Asia. Paleoheterodon and Neonatrix could have originated in Asia and subsequently reached Europe on one hand and North America on the other. Texasophis may have originated in North America and followed the same route as Micrurus and Albaneryx, but an alternative hypothesis is that it originated in Asia and spread toward Europe and North America in the same manner as Paleoheterodon and Neonatrix.     

Late Cretaceous radiolarian biochronology of the Pedro Brand section,Tireo Group,eastern Central Cordillera,Dominican Republic: A contribution to the stratigraphy of the Caribbean Large Igneous Province

The Tireo Group in the eastern Central Cordillera (Dominican Republic) is part of the Jarabacoa Block, composed of a Pacific-type Jurassic ocean floor (Loma La Monja, overlain by the El Aguacate ribbon Chert), intruded and overlain by an early CLIP (Carribean Large Igneous Province)-type plateau, the Duarte Complex, which is in turn unconformably overlain by arc-type rocks of the Tireo Group. This group exhibits a 3-km thick sequence of arc-related volcanic and volcano-sedimentary rocks, including tuffaceous chert and mudstone studied for radiolarians in this paper. The Siete Cabezas Formation, considered to be the last Campanian–Maastrichtian CLIP-type volcano-sedimentary sequence, overlies the Tireo Group. A controversy about earlier radiolarian dating of the Tireo Group, considered until now as part of the Siete Cabezas Formation, encouraged us to study a well-exposed section located 3 km NE of Pedro Brand village. Seven samples of laminated siliceous mudstones and cherts yielded around 40 common and well-preserved radiolarian taxa. Based on maximum ranges of taxa published in several regional zonations and on a comparison with a Turonian–Coniacian sample calibrated by planktonic foraminifera (the Deva Beds from Romania), we determine a Turonian–Coniacian age for the Pedro Brand section. A ⁴⁰Ar–³⁹Ar whole rock age of 75.1 ± 1.1 Ma, obtained in a basalt dyke crosscutting the radiolarian bearing rocks, provides a Late Campanian consistent minimum age for the pelagic–hemipelagic Pedro Brand section. Including the re-interpretation of earlier radiolarian work, we conclude that the studied rocks of the Tireo Group are older than the Maastrichtian ⁴⁰Ar–³⁹Ar ages on plagioclase of the Siete Cabezas Formation. The studied dyke in the Pedro Brand section geochemically resembles the overlying Siete Cabezas and Pico Duarte basalts and could be a feeder dyke of those. However, a tectonic superposition of the Siete Cabezas cannot be excluded, since earlier ⁴⁰K–⁴⁰Ar basalt ages of this unit are Aptian–Albian and Cenomanian–Turonian. The Jarabacoa Block is considered as the most complete outcrop section of Pacific ocean crust overlain by a first (Aptian–Albian) phase of CLIP-type activity, followed by the development of a Cenomanian–Santonian intraoceanic arc, which is in turn overlain by a late Campanian–Maastrichtian CLIP-like phase.     

Nouvelles recherches géologiques et malacologiques sur le Quaternaire de la province de Tarfaya (Maroc méridional)

The province of Tarfaya located in the South of Morocco and West of Anti-Atlas is a part of the wide costal basin of West Sahara. Marine Pleistocene is poorly represented: three levels only can be numbered. Moghrebian, often attributed to Pliocene, possesses a doubtless quaternary gastropoda fauna. Messaoudian (Maarifian according to G. Lecointre) is known from a single site and contains a relatively warm fauna. Recent deposits, outcropping at less than +5 meters, cannot easily been determined by means of paleontology: they are Ouljian and perhaps Harounian-Rabatian. Compared with type-sections of Casablanca, an increase of southern influences in the faunas is noted: especially the Messaoudian shells present a rather obvious tropical type.     

Relations entre le benthos,la derive,le rythme alimentaire et le taux de consommation de truites communes (S. trutta L.) en canal experimental

Relationships between benthos, drift, feeding rhythm and consumption rate of brown trout were investigated in an artificial stream in late spring. There are good correlations between insects activities and feeding rhythm of the trout. There are two feeding periods, the first one, more important, occurs at dusk and the second one in early morning. Daily ration is 6% of trout dry weight.     

Activité oxydasique de l''oxydoréductase de la xanthine, spécifique de la classe des mammifères

In every species other than mammals xanthine oxidoreductase behaves as a dehydrogenase, never as an oxidase. In three mammalian species, the enzyme acts intracellularly as a dehydrogenase, but its class-specific ambivalence allows its extracellular conversion into an oxidase.

Résumé

En dehors de la classe des Mammifères, l'oxydoréductase de la xanthine ne se comporte jamais comme une oxydase. Chez les Mammifères, une ambivalence de la molécule permet l'expression d'une activité déshydrogénasique (NAD) dans la cellule, et d'une activité oxydasique en dehors de la cellule.     

Influence de quelques acides aminés libres de l'ovule sur la croissance et le développement cellulaire in vitro du tube pollinique chez Juniperus communis (Cupressaceae)

Influence of some free amino acids of the ovule on growth and cellular development of the pollen tube of Juniperus communis L. in vitro. The extraction and analysis of free amino acids show that a partial complementary relationship exists between the amino acids of the pollen and those of the ovule of Juniperus communis. The main free amino acids of the pollen are threonine, proline, arginine and γ-aminobutyric acid; those of the ovule are threonine, serine, alanine, citrulline and glycine. The addition of the main amino acids of the ovule in the pollen culture media increased the growth and the cell development of pollen tubes cultured in vitro. This indicates the nature of the correlations which exist between the male and female gametophyte of Juniperus communis.