Creusia oraniensis nov. sp. (Cirripedia,Creusiinae) du Miocène terminal d'Oranie (Algérie)

A new Balanomorph Cirripedia, in the subfamilyCreusiinae, Creusia oraniensis nov. sp., is described. It is found in various reef sites of the Uppermost Miocene near Oran (Algeria). Its paleoecology is also discussed.     

Processus dynamiques de reconstitution dans la série du Quercus ilex en Corse

The use of permanent plots in representative sites of various phytosociologically defined stages of the Quercus ilex series in NW Corsica allows us to analyse the natural dynamical process occurring in the development sequence. The regular floristic analysis of stands and transects (mainly using a linear cover measure) during 5 yr not only shows variations of composition and structure but also results in a diachronic understanding of the temporal relations between the stages. The study of forest plots (structure, number and development of seedlings) enables us to generalize the principle of ponctual and cyclic self-transformation of climatic and subclimatic stages.

Avec la collaboration de Mme D. Chiaverini pour l'illustration. II nous est agréable de remercier ici l'A.P.E.E.M. (Association pour l'Etude Ecologique du Maquis) pour la possibilité qui nous a été donnée d'utiliser les installation du laboratoire de Pirio, ce qui a grandement facilité les campagnes successives de terrain.     

Répartition transversale des macroinvertébrés benthiques dans un bras du Rhône

While the downstream distribution of benthic macrofauna has been studied in many rivers, its transverse distribution remains rather unknown. The present work concerns this problem in a semi-regulated arm of the Rhône. The characteristics of this arm are: width 80 m, depth 0.5 to 1 m in the section studied, pebble substrate, rocky banks, discharge regulated at 30 m³. s^-1 except for floods up to 1 000 m³. s^-1. The substrate was sampled with a Hess cylinder which collects the fauna present on 0.125 m². Eight stations were located across the river, and 22 samples were collected. Correspondence analysis was applied to the Taxa X Samples matrix, and the results were studied by analysis of inertia, canonical correlation and variance analysis. A close correlation appears between the faunistic structures and the stations. Two main units are revealed. The first one includes a ten meters band along each bank, the other covers the main part of the bed, between these two bands. The two units differ in their taxonomic richness and abundance, many taxa being only present along the banks. A symmetrical gradient of density appears between the channel and the banks. Moreover, the fifth factor of the correspondence analysis reveals that the fauna of one side is not identical to that of the other. The cause of these structures remains uncertain. Among the different parameters, the distance from the banks seems to be the most significant. The existence of a gradient may be due to a dissemination of the fauna from the banks towards the channel. This study suggests the importance of the banks in the dynamics of the benthic fauna of large, fast-flowing rivers, especially in connection with the floods. This must be taken into account when sampling in such rivers.     

Le « Moustérien » de Tipasa et de Ténès (littoral ouest algérois) dans la lecture climatique du second pléniglacaire

The excavations that we undertook, in 1985, in the prehistoric site of Sidi Saïd, in Tipasa (Algeria), allowed us to observe an unusual archaeological stratigraphy. An aterian industry with pedunculated pieces, surmounted by a Mousterian, rich in scrapers and single-sided retouching points, almost systematically in flint, with reduced shapes and strongly reduced (Aterian under Mousterian). This unusual case has led us to consider the reading of the Mousterian-Aterian/Ibéromaurusien passage in a different way and at the same time to take a new look at the work carried out so far on the west coast of Algiers, especially those of Lower cave of the Tenes lighthouse, west of Tipasa. An attempt to compare and correlate the site of Sidi Said and the Lower Cave of the Ténès lighthouse, enabled us to consolidate our conviction on the existence of an aterian stratigraphically below the Mousterian and to discover an original lithic industry of Mousterian tradition, with strongly reduced forms, which would be placed between stratigraphically between the Aterian and the Iberomaurusian. This industry which does not yet have a name or place in the chronology, “curiously” recalls the case of the Middle Solutrean of southwestern Europe, in the context of the second pleniglacial.     

Contribution à la connaissance des Bathysciina de la «série d’Aphaobius» (sensuJeannel, 1924) (Coleoptera: Leiodidae,Cholevinae, Leptodirini)

De nouvelles informations sont données concernant les genres de Leptodirini de la série d’«Aphaobius» (sensu Jeannel 1924). Oryotus ausmeieri n.sp. du nord de la Slovénie est décrite. Oryotus indentatus Pretner, 1955 jusqu’à présent considéré comme sous-espèce d’Oryotus micklitzi Reitter, 1885 est élevé au rang d’espèce. Neotropospeonella decui Pace, 1983 est mise en synonymie avec Oryotus ravasinii Müller, 1922, entraînant la synonymie du genre Neotropospeonella Pace, 1983 avec Oryotus Miller, 1856 et des sous-tribus correspondantes: Neotropospeonellina Perkovsky, 1997 et Bathysciina Horn, 1880. Pretneria droveniki Etonti, 2001 est transférée dans le genre Oryotus et mise en synonymie avec O. micklitzi Reitter, 1885; Pretneria latitarsis soriscensis n. ssp. est décrite. Le mâle de Lotharia angulicollis Mandl, 1944 est décrit pour la première fois, confirmant l’étroite parenté de cette espèce avec le genre Aphaobius Abeille de Perrin, 1878.     

Éléments de biogéographie et d'écologie desMollusques Quaternaires et actuels du banc d'Arguin (Mauritanie)

Situated in arid area, the «banc d'Arguin landscomposes a littoraly and sandy biotope. Some stony headland could be found on the sea side.The malacofauna belongs to the senegalian type but look impoverished. Therefore, one can found some lusitanian species mainly on stones and six endemic species of the senegalo-mauretanian littoral. With the same lusitanian influences and the same endemic species, the quaternary fauna looks like the actual one belonging to the senegalian type.     

Clausiliidae (Gastropoda,Euthyneura)du Néogène du bassin rhodanien (France)

Clausilids of the Neogene of the Rhone province are known by twelve species among whose three are news. During the Miocene, and specially during its upper part, the only genus Triptychia is undoubtedly known. It is represented by Triptychia (Milne-Edwardsia) lageti nov. sp. and two others species.The absence of others genera of Clausilids during this period and in this province makeup an information of bads conditions of growth.During the Pliocene, the Clausilids fauna is very varied. Genus Triptychia includes twospecies: T. (M.-E.) terveri, in the northern part of the Rhone province and T. (M.-E.) sinistrorsa in its southern part. Serrulina, Clausilia, Iphigena, Laminifera and Nordsieckia nov. gen. (near Serrulina) are to be found in many outcrops. Two news species of Laminifera: L. (L.) meini and L. (Polloneria) ballesioi are characteristics of the pliocene southern fauna of the Rhone province.Many Clausilids of the Neogene have disappeared because of the Quaternary bad climatic circumstances. But during the Pliocene appear the genus Clausilia very abundant actually in the western Europe.     

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.     

Étude palynologique du pliocène de la côte d'azur (France) et du littoral ligure (Italie)

Pollen analysis of Pliocene marine clays in coastal Alps paleogulfs is supported by biostratigraphic records according to foraminifers and accessorily to nannoplankton. From the seashore up to elevated areas, the region was occupied by forests mostly constituted by Gymnosperms (Taxodiaceae particularly). The Lower Pliocene vegetation was also characterized by local differences related to the substratum. Pollen assemblages changed in the Earliest Piacenzian; this event is probably to be related to a climatic fluctuation already evidenced in the Northwestern Mediterranean region.     

Le genre RichterellaAvram (Ammonitina,Périsphinctidés) dans le Tithonique inférieur de la bordure ardéchoise (Sud-Est de la France): Dimorphisme et variabilité

Dimorphism in the genus RichterellaAvram is confirmedon the basis of material collected in Ardeche (South east France) principally in the beds of the Fallauxi zone, from the localities of Le Pouzin and Broyon. The microconch, R. richteri (Oppel), lacks lateral lappets but a ventral horn, formed by the strongly projected forward secondary ribs, is present. The macroconch is «Lemencia praerichteriDonze & Enay. These two forms are united in the same species, R. richteri, and then in the same genus, Richterella. The microconch, which is generally better preserved than macroconch in the studied material, shows a greater variability of ribbing than previously thought, due to the poor illustrations of the lectotype of richteri (reproduced here) which showed only dichotomous ribs. The genus Richterella loses its original dimorphic sense and since its origins and its possible derivations are unknown, it became a taxon defined on morphological bases. The forms from Ardeche bear a greater resemblance to the Spanish ones than they do to the Roumanian forms. The stratigraphical and faunal contexts of Richterella in Ardeche are discussed in this work.     

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.     

Les prémices d'une agriculture diversifiée à la fin du Mésolithique dans le Val de Loire (Loire armoricaine,France)

Pollen analyses carried out in the Armorican Massif have already drawn our attention to the early appearance (at the end of the Mesolithic period/beginning of the Neolithic period) of several taxa, particularly Cerealia. New studies conducted in the Val de Loire region of France and in the surrounding tributaries seem to confirm these initial findings. These studies also provided more information about the introduction of Fagopyrum and Juglans at about 6000 BC. We hypothesise that ‘pre-domesticated’ agriculture took place in this area at this time and that it might have been brought to this area by southern migration. To cite this article: L. Visset et al., C. R. Palevol 1 (2002) 51–58.     

Apports de la palynologie a la connaissance du Pliocène du Roussillon (sud de la France)

The present study illustrates clearly how pollen analysis may be applied to stratigraphy from a botanical point of view. Within a chronologically reliable frame (Middle Pliocene for the marine deposits on the basis of Foraminifera record; two subzones for continental deposits on the basis of Mammals record: Hautimagne for Terrats fauna, Sète for Serrat-d'en-Vacquer fauna), palynology provides a good stratigraphical boundary: the extinction of the Taxodiaceae. In a remblayage area, it is established that a continental level is not necessarily younger than a marine one unless they are superposed. Many profiles are replaced according to the «progradation of the pliocene gulf of Roussillon. The boundary between marine and continental deposits cuts through the chronological line of the Taxodiaceae extinction. The flora investigated (93 taxa) is the first known for the Pliocene of this area. The extinction of the Taxodiaceae in southern France has a climatic cause: the setting in of a mediterranean rhythm (dry summers). This extinction is much older than the one which took place in Italy (Tiberian boundary) and in the Netherlands (Reuverian-Pretiglian boundary).     

Implantation du genêt à balais,précédent cultural et dynamique du sol dans les friches (Bretagne,France)

The soil dynamics of old-fields, characterized by the early establishment of broom (Cytisus scoparius L.), is analysed in the Breton bocage. The role of former land use practices is estimated by comparing two similar plant successions, post cultivation and post pasture. Different variables (organic matter, mineral N content, microbial biomass, total microbial activity and mineralization) are measured within the soil layer disturbed by farming (between –5 and –25 cm). One year after abandonment, the parameters taken into account show similar values for both series. After 8 years, in broom thickets, the two soil series are characterized by an increase in microbial activity, organic matter and mineral N contents. However, the post cultivation thicket differed by higher N content and mineralization rate than the post pasture thicket, but also by a smaller microbial biomass. It appears that, if the development of similar vegetational communities promotes the same kind of soil dynamics, the former land use practices significantly modify this evolution, for at least the first 8 years following abandonment.     

Analysis of wet edaphic riparian communities of a Mediterranean hydrographic network: the Arc (Bouches-du-Rhône,France)

The composition of benthic communities is a good criterion to estimate water quality. Is this also true of the wet edaphic riparian invertebrates, less directly exposed to the impact of the water? What abiotic factors determine the distribution of species within a hydrosystem? These questions were addressed, using the River Arc and its hydrographic network, subject to various anthropogenic aggressions (urbanization, industry, agriculture) and offering varied hydrochemical situations. The riparian population (158 taxa) was analysed, using Reciprocal Averaging (9 sampling points on the main course and its tributaries). Results show that spatial variation of the edaphic riparian zoocenosis is chiefly determined by the nature of the substratum and, to a lesser extent, by the hydrologic instability of the water course. However, it can respond to some constraints of the environment like benthic macroinvertebrates.