80 research outputs found

    Falsolikanella danilovae RADOIČIĆ ex BARATTOLO 1978, n. comb., a diploporacean alga from the Urgonian facies

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    International audienceOriginally described as Likanella danilovae RADOIČIĆ 1969, nom. nud., the species partly revisited hereafter has been lately ascribed to the genus Praturlonella BARATTOLO 1978 and validly published under this new combination. This short paper aims to demonstrate that it should be referred to the genus Falsolikanella GRANIER 1987

    Deciphering voids in Dasycladales, the case of Dragastanella transylvanica, a new Lower Cretaceous triploporellacean genus and species from Romania

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    AbstractDragastanella transylvanica n. gen. n. sp. is described. Its calcified skeleton contains numerous voids, partly related to the molds of soft parts of the alga, but also related to lack of calcification. Interpretation of these voids, especially their attribution to original structures (e.g., primary lateral versus reproductive organ), has important implications for the taxonomic position of the alga, even at the family level. Examination of key sections that include the boundary between sterile and fertile parts of the alga excludes the occurrence of external reproductive organs. Unusual, paired pores in the outer part of the mineralized skeleton reflect an asymmetry within the whorl, excluding the presence of secondary laterals. The alga is characterized by a cylindrical to club-shaped thallus bearing only phloiophorous primary laterals arranged in whorls and flaring outwards, forming a cortex. Mineralized lenticular reproductive organs containing cysts set in the equatorial plane (Russoella-type gametophores) occur inside primary laterals (cladosporous arrangement of the reproductive organs). These characters support establishment of the new genus Dragastanella. Dragastanella transylvanica n. gen. n. sp. resembles species previously referred to Zittelina (Zittelina hispanica and Zittelina massei) and Triploporella (Triploporella matesina and Triploporella carpatica). Except for Triploporella carpatica, whose mineralized skeleton does not permit confident attribution to either Triploporella or Dragastanella n. gen., the other species must be ascribed to Dragastanella n. gen. Therefore, the following new combinations are proposed: Dragastanella hispanica n. comb., Dragastanella massei n. comb., and Dragastanella matesina n. comb. Despite widely overlapping biometrical measurements, these species can be differentiated by the size and location of their reproductive organs, the pattern of calcification around the primary laterals, and relationships among structural parameters such as the size of laterals, number of laterals per whorl, and distance between whorls

    Systématique des algues rouges du Miocène moyen de la Formation Gârbova de Sus (Bassin Transylvanien, Roumanie)

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    This study describes seventeen non-geniculate coralline algal species (orders Corallinales, Hapalidiales and Sporolithales) from the middle Miocene (lower-middle Badenian) red-algal limestones of the Transylvanian Basin, Gârbova de Sus Formation. For the description and identification at species level, we follow the common diagnostic features used for fossil species and some characters that are used as diagnostic for modern species (roof morphology for asexual conceptacles, the presence/absence of a layer of elongated cells below sporangial compartments and number of cells in paraphyses for Sporolithon, and measurements of gametangial and carposporangial conceptacles). Female conceptacles of Spongites fruticulosus Kützing are for the first time described in fossil material. We propose the attribution of Lithophyllum platticarpum Maslov to Spongites fruticulosus Kützing as a gametangial thallus with male conceptacles.Cette étude présente dix-sept espèces d'algues corallines non articulées (ordres des Corallinales, des Hapalidiales et des Sporolithales) provenant des calcaires à algues rouges du Miocène moyen (Badénien inférieur-moyen) de la Formation Gârbova de Sus du Bassin Transylvanien. Pour la description et l'identification au niveau spécifique, nous adoptons les caractéres diagnostiques habituellement utilisés chez les espèces fossiles et certaines caractéristiques qui sont considérées comme diagnostiques chez les espèces modernes (morphologie du toit pour les conceptacles asexués, la présence ou l'absence d'une couche de cellules allongées sous les compartiments sporangiaux et le nombre de cellules dans les paraphyses de Sporolithon, et les mesures des conceptacles gamétangiaux et carposporangiaux). Les conceptacles femelles de Spongites fruticulosus Kützing sont décrits pour la première fois chez des formes fossiles. Nous proposons le rattachement de Lithophyllum platticarpum Maslov à Spongites fruticulosus Kützing pour un thalle gamétangial à conceptacles mâles.2016-05-24T13:31:28

    Reinstatement of the genus Bakalovaella Bucur, 1993 (Dasycladeae, Dasycladaceae), and a description of its earliest Cretaceous representative

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    Une nouvelle espèce de Dasycladacée de l'Hauterivien d'Aquitaine (France) est décrite. Elle est attribuée au genre Bakalovaella Bucur, 1993, réhabilité ici. D'un point de vue phylogénétique, en se fondant sur le modèle du "piston élévateur", ce taxon appartiendrait à une lignée issue des Diploporacées.A new Dasycladacean species found in Hauterivian strata in Aquitaine is described. It is ascribed to the genus Bakalovaella Bucur, 1993, which is reinstated here. From a phylogenetic point of view, based of the "lifting piston" model, this taxon should be part of a lineage derived from the Diploporaceae

    Upper Aptian calcareous algae from Pădurea Craiului (Northern Apuseni Mountains, Romania)

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    A study of calcareous strata previously assigned to the Barremian-Early Aptian interval in the northwestern part of Pădurea Craiului, (Apuseni Mountains), led to the identifi cation of a icropaleontological association indicative of a Late Aptian age. Unequivocal evidence for the Late Aptian assignment of these limestones is the presence throughout the sequence of two orbitolinid species, Mesorbitolina texana (ROEMER) and Mesorbitolina subconcava (LEYMERIE). The most interesting sections are located in the neighbourhood of Subpiatră, where both outcrops and a quarry facilitated detailed analyses. In this area, the Upper Aptian succession consists basically of three types of macrofacies: 1) limestone with rudists; 2) limestone with Bacinella and 3) limestone with corals, each of them showing several types of microfacies. Bacinella structures are the most common feature in the whole succession, irrespective of the macrofacies. This paper focuses on an algal association that was identifi ed in several levels within the succession. Dasycladalean algae are more frequent, and are commonly found in grain-dominated fabrics (mostly grainstone textures), in association with orbitolinid foraminifera and bioclasts of corals, rudists and gastropods. However, a few species are present only in mud-dominated fabrics (i.e. lower-energy intervals). The dasycladalean association from the Upper Aptian deposits of Pădurea Craiului is of special interest, for this group registered a dramatic decline at the Lower Aptian/Upper Aptian boundary, as confirmed by the relative scarcity of the Dasycladales in the Upper Aptian carbonate deposits

    The IMAM case. Additional investigation of a micropaleontological fraud

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    International audienceStarting in 1996 and for almost a decade, M.M. IMAM contributed to twelve papers published in international geological journals. These papers dealt with the micropaleontology and biostratigraphy of Cretaceous to Miocene series from Egypt and Libya. They were abundantly illustrated in order to support the author's findings and interpretations. However most photographic illustrations (189 at least) were fabricated with material lifted from the publications of other authors, commonly from localities or stratigraphic intervals other than those indicated by M.M. IMAM

    Praeorbitolina claveli n.sp. (foraminifère benthique) de l'Aptien inférieur sensu lato (Bédoulien) du centre de l'Iran

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    Un nouveau foraminifère orbitolinidé, Praeorbitolina claveli n.sp., est identifié dans l'Aptien inférieur (Bédoulien) de l'Iran central. Il se caractérise par un appareil embryonnaire constitué d'une zone subembryonnaire subdivisée ainsi que d'une déutéroconque. L'association d'orbitolinidés d'âge Barrémien-Aptien de cette région présente un caractère typiquement nord-téthysien (e.g., "association à Valserina" de CHERCHI et SCHROEDER, 1973).The new orbitolinid foraminifer, Praeorbitolina claveli n.sp., is described from the Lower Ap-tian (Bedoulian) of Central Iran. It is characterized by an eccentric embryonic apparatus displaying both a subdivided subembryonic zone and a deuteroconch. The Barremian-Aptian orbitolinid association of this area has a typical northern Tethyan character (e.g., "association à Valserina" of CHERCHI and SCHROEDER, 1973)

    Polyphysaceae fertile caps in Hungarian Sarmatian sediments

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    Three fragments of reproductive caps have been discovered in the Sarmatian limestones of Tinnye (Hungary). They are assigned to the genus Acetabularia (Polyphysaceae, formerly Acetabulariaceae). Two of these fragments are quite well preserved with nine rays each. One specimen bears distinct spines at the outer ends of long rays, whereas another one has short rays with rounded outer ends and, possibly, a partially preserved corona. The third fragment is characterized by very elongated rays containing numerous gametangia

    Les calcaires du Jurassique supérieur-Crétacé inférieur du Massif de Hăghimaș (Carpathes orientales, Roumanie) : Microfaciès, microfossiles et environnements de dépôt.

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    The Hăgimaş Massif provides important data for reconstructing the geological evolution of the Transylvanian Carbonate Platform. This unit is present nowadays in the basement of the Transylvanian Depression and as large-scale olistoliths, which crop out in various locations in the Eastern Carpathians and Apuseni Mountains. They contain a large variety of microfacies as well as microfossil assemblages partly encompassing the Jurassic/Cretaceous boundary. This study presents a detailed account of uppermost Jurassic-lowermost Cretaceous limestones from the Lapoş Valley (Hăghimaş Mountains) containing two distinct successions separated by a fault. The first succession contains platform margin and inner platform deposits (subtidal, intertidal) whereas the second one consists of inner platform deposits (shallow-subtidal to peritidal carbonates). The Upper Jurassic Stramberk-type facies is overlain by lower Berriasian regressive peritidal limestones. The upper Berriasian-? lower Valanginian consists mainly of inner platform deposits. They contain alternating, high and low-energy carbonates with rare calpionellids and calcispheres. The age assignment is based on a rich and diverse micropaleontological assemblage containing similar biota reported from other regions of the Tethysian Realm.Le Massif de Hăghimaș fournit des données cruciales pour reconstruire l'évolution géologique de la plate-forme carbonatée transylvanienne. Cette unité est présente de nos jours dans le substratum de la dépression transylvanienne sous forme d'olistolites de grandes dimensions qui affleurent en de nombreuses localités des Carpathes orientales et des monts Apuseni. Ils comportent une grande variété de microfaciès, ainsi que des associations micropaléontologiques, qui couvrent en partie la limite Jurassique/Crétacé. Cette étude présente dans le détail un affleurement de calcaires du Jurassique terminal-Crétacé basal de la vallée de Lapos (Monts Hăghimaș) comportant deux séries distinctes séparées par une faille. La première série correspond à des dépôts marginaux de plate-forme et de plate-forme interne (subtidaux, intertidaux), tandis que la seconde correspond à des dépôts de plate-forme interne (carbonates peu profonds subtidaux à péritidaux). Les faciès jurassiques supérieurs de type Stramberg sont surmontés par les calcaires péritidaux régressifs du Berriasien inférieur. Le Berriasien supérieur - ? Valanginien inférieur est principalement représenté par des calcaires de plate-forme interne. Ils comportent une alternance de carbonates de haute et de basse énergies avec de rares calpionelles et des calcisphères. Leur datation se fonde sur un assemblage micropaléontologique riche et diversifié comportant des organismes semblables à ceux décrits dans d'autres régions du domaine téthysien

    Passage Jurassique-Crétacé sur la plate-forme carbonatée gétique (Carpathes méridionales, Roumanie) : Foraminifères et algues benthiques

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    The carbonate succession of the Piatra Craiului Massif, i.e., the eastern part of the Getic carbonate platform (Southern Carpathians, Romania), comprises reefal and peritidal limestones that contain a diverse microfossil assemblage composed mainly of calcareous green algae and benthic foraminifera. The biostratigraphically most significant benthic foraminifera found in the several sections studied are described; some (Anchispirocyclina lusitanica, Neokilianina rahonensis, Bramkampella arabica, Everticyclammina praekelleri) are reported for the first time in this area. Hence, assemblages of both foraminifera and calcareous algae characterize three biostratigraphic intervals in the studied succession, the Kimmeridgian - lower Tithonian, the upper Tithonian - lower Berriasian, and the upper Berriasian - ? lower Valanginian intervals. The main microfacies types (bioclastic rudstone, coral-microbial boundstone, bioclastic grainstone, interbedded mudstones and wackestones with cyanobacteria nodules) as well as both the foraminifera and the calcareous algae are paleoecological indicators that may contribute to the decipherment of the depositional environments and to building a depositional model for the eastern part of the Getic carbonate platform at the Late Jurassic-Early Cretaceous transition.La série carbonatée du Massif de Piatra Craiului, c'est-à-dire de la partie orientale de la plate-forme carbonatée gétique (Carpathes méridionales, Roumanie), est constituée de calcaires récifaux et péritidaux qui recèlent des associations variées de microfossiles constituées d'algues vertes calcaires et de foraminifères benthiques essentiellement. Parmi les foraminifères benthiques identifiés dans les nombreuses coupes étudiées, nous décrivons ceux auxquels on attribue une certaine valeur biostratigraphique. Quelques-uns (Anchispirocyclina lusitanica, Neokilianina rahonensis, Bramkampella arabica, Everticyclammina praekelleri) sont signalés pour la première fois dans ce secteur. De ce fait, dans la série étudiée, grâce aux associations combinées de foraminifères et d'algues calcaires, nous caractérisons trois intervalles biostratigraphiques : le Kimméridgien - Tithonien inférieur, le Tithonien supérieur - Berriasien inférieur et le Berriasien supérieur - ? Valanginien inférieur. Les principaux types de microfaciès (rudstone bioclastique, boundstone corallien-microbien, grainstone bioclastique, alternances de mudstones et de wackestones à nodules cyanobactériens) sont des indicateurs paléoécologiques qui, avec les foraminifères et les algues calcaires, peuvent contribuer au décryptage des environnements de dépôt et à la construction d'un modèle dépositionnel pour la partie orientale de la plate-forme carbonatée gétique à la transition du Jurassique supérieur au Crétacé inférieur
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