72 resultados para Spiders, Fossil
Resumo:
Se estudian algunas formas de Briozoos del Cuaternario del delta del Llobregat (tocando a la ciudad de Barcelona). Se reconocen dos especies del gnero Cellaria, una Discoporella, una Cupztladria y una Porclla. Adems de una discusin sistemtica sobre el gnero Cellaria y Porclla se dan datos micromtricos abundantes y se establecen comparaciones con los dados por otros autores insinundose algunas conclusiones.
Hallazgo de 'Harrisichara lineata' Grambast, en el yacimiento del Parés, (Sant Boi de Lluçanés, Vic)
Resumo:
Palliolum (L.) excisum (Bronn) se encuentra en España en tres áreas: Cordillera Litoral (Cordillera Costero-Catalana), región de Alicante (Cordilleras Béticas) y Depresión del Guadalquivir. En las dos primeras tiene una distribución puntual, mientras que en la última son frecuentes las localidades en las que se presenta. Litológicamente es una especie que va asociada a las facies detríticas finas, faltando en las facies gruesas y carbonatadas. En la región maditerránea y en la atlántica del sur de Europa tiene una edad pliocénica. Sólo en el Camping Francás (España) correspondería al Mioceno superior y no se puede descartar la posibilidad de que esta localidad pudiera pertenecer al Plioceno. En el contravertido yacimiento de Dar-Bel-Hamri (Marruecos) presenta una posición estratigráfica dudosa y su edad se ha considerado como Massiniense.
Resumo:
Using X-Ray techniques, the boring activities of various Invertebrates on Bivalvia of wmian age were studied. Emphasis is placed on the boring activity of Porifera and their apparent preselection of the species bored, based on: a) the mineralogical composition, and/or b) the microstucture, andlor c) some special environmental conditions, or d) combinations of these three posibilities.
Resumo:
Se cita por primera vez el hallazgo de un coral colonia en Montjuich, Thegioastrea multisepta (SISMONDA) y se estudian las posibles causas de la rareza de este tipo de organismos en este yacimiento
Resumo:
Se describen en este trabajo los Insectvoros y Roedores de tres localidades de la Seu d'Urgell. Dos de ellas (Ballestar y Can Petit, pertenecientes a la formacin Ballestar) presentan una microfauna del Vallesiense inferior con Cricetulodon hatanbergeri, Muscardinus crusafonti, Myoglis meini, etc. La otra (La Bastida, en la Formacin Piedra) presenta una microfauna perteneciente al Vallesiense superior, con Progonomys cathalai como especie predominante. El análisis de esa fauna modifica el esquema estratigráfico propuesto hasta el presente para la cuenca de la Seu d'Urgell, ya que siempre se había sostenido que la Formación Piedra era anterior a la Formación Ballestar. De ambas formaciones se da una breve descripción sedimentológica.
Resumo:
En esta nota preliminar se dan a conocer dos nuevos yacimientos de microvertebrados situados en la cuenca del Valles-Penedes. La asociación de Roedores sita ambas localidades (Can Mar Vell y Can Julia) en la MN-4, equivalente al Burdigaliense superior. Dicha asociación y las caracteristicas litológicas y sedimentológicas de la unidad litoestratigráfica que la contiene, indican la existencia de reas lacustres y palustres en torno a las que lacobertera vegetal alcanzaba un notable desarrollo. Estas zonas lacustres podan pasar lateralmente a reas distales y proximales de abanicos aluviales, en las que se desarrollaba una intensa sedimentación detrítica y predominaban las condiciones subaéreas.
Resumo:
Un muestreo intensivo del clasico yacimiento de mamíferos fósles de Santpedor ha dado como resultado la presencia de Theridomys aff. aquatilis, Gliravus aff. priscus, Eucricetodon atavus y Pseudoltinomys gaillardi. Esta asociacin permite atribuir 1os niveles del yacimiento al Oligoceno inferior mas bajo (nivel de Hoogbutsel)
Resumo:
Macroalgae is the dominant trophic group on Mediterranean infralittoral rocky bottoms, whereas zooxanthellate corals are extremely rare. However, in recent years, the invasive coral Oculina patagonica appears to be increasing its abundance through unknown means. Here we examine the pattern of variation of this species at a marine reserve between 2002 and 2010 and contribute to the understanding of the mechanisms that allow its current increase. Because indirect interactions between species can play a relevant role in the establishment of species, a parallel assessment of the sea urchin Paracentrotus lividus, the main herbivorous invertebrate in this habitat and thus a key species, was conducted. O. patagonica has shown a 3-fold increase in abundance over the last 8 years and has become the most abundant invertebrate in the shallow waters of the marine reserve, matching some dominant erect macroalgae in abundance. High recruitment played an important role in this increasing coral abundance. The results from this study provide compelling evidence that the increase in sea urchin abundance may be one of the main drivers of the observed increase in coral abundance. Sea urchins overgraze macroalgae and create barren patches in the space-limited macroalgal community that subsequently facilitate coral recruitment. This study indicates that trophic interactions contributed to the success of an invasive coral in the Mediterranean because sea urchins grazing activity indirectly facilitated expansion of the coral. Current coral abundance at the marine reserve has ended the monopolization of algae in rocky infralittoral assemblages, an event that could greatly modify both the underwater seascape and the sources of primary production in the ecosystem.
Resumo:
En el presente trabajo se describen las principales características estratigráficas y sedimentológicas del relleno de la fosa de la Cerdanya. A partir de éstas se han diferenciado dos unidades: la Unidad Neógena Inferior y la Unidad Neógena Superior que reflejan dos situaciones tectónicas diferentes. La Unidad Inferior corresponde al período de formación y posterior evolución de la fosa bajo el movimiento direccional de la falla NE-SW de la Tet, mientras que la Unidad Superior refleja una situación extensional generalizada. La revisión de los numerosos yacimientos de Mamíferos fósiles de la Unidad Neógena Inferior, expuesta en esta nota, permiten concluir que esta se sedimentó en el Vallesiense. Por contra, el hallazgo del nuevo yacimiento de Can Vilella, indican que la sedimentación de la Unidad Superior se inició en el Turoliense superior (MN 13)
Resumo:
In the southeastern Ebro Foreland Basin, the marine deposits of Lutetian and Bartonian age show excellent outcrop conditions, with a great lateral and horizontal continuity of lithostratigraphic units. In addition, the rich fossil record -mainly larger foraminifers-, provides biostratigraphic data of regional relevance for the whole Paleogene Pyrenean Basin, that can be used for the Middle Eocene biocorrelation of the western Tethys. This contribution is a sedimentary and biostratigraphic synthesis of the basic outcrops and sections of the Lutetian andBartonian marine and transitional deposits in the southeastern sector of the Ebro Foreland Basin.
Resumo:
In this study we analyze and explain the formation of the constructive micrite envelope in the vadose continental environment. This constructive micrite envelope shows a wide variety of textural components. The principal textural components are: microorganisms, micritic and microspar LMC cement, whisker crystals, microfibres and aggregates of LMC acicular crystals. The main microorganisms are hyphae fungi, although actynomicetes and bacteries also occur. The constructive micrite envelope is due to the action of calcified filaments (hyphae fungi) which collapse and coalesce forming an intertwined mesh as well as due to the precipitation of micritic and microspar cement. The whisker crystals, microfibres and aggregates of LMC acicular crystals are secondary microtextures. Constructive micrite envelopes does not indicate a specific diagenetic environment. The constructive micrite envelopes present irregularities or bumps at the outer surface of the grains, and the destructive micrite envelopes present irregularities towards the grain interior. This morphologic criterion is useful to differenciate the micrite envelope origin, constructive or destructive, in the fossil record.
Resumo:
Over the last decades, there has been an increasing interest on the chronology, distribution and mammal taxonomy (including hominins) related with the faunal turnovers that took place around the Pliocene-Pleistocene transition [ca. 1.8 mega-annum (Ma)] in Europe. However, these turnovers are not fully understood due to: the precarious nature of the period's fossil record; the"non-coexistence" in this record of many of the species involved; and the enormous geographical area encompassed. This palaeontological information gap can now be in part bridged with data from the Fonelas P-1 site (Granada, Spain), whose faunal composition and late Upper Pliocene date shed light on some of the problems concerning the timing and geography of the dispersals.
Resumo:
This paper analyses the international inequalities in CO2 emissions intensity for the period 1971–2009 and assesses explanatory factors. Multiplicative, group and additive methodologies of inequality decomposition are employed. The first allows us to clarify the separated role of the carbonisation index and the energy intensity in the pattern observed for inequalities in CO2 intensities; the second allows us to understand the role of regional groups; and the third allows us to investigate the role of different fossil energy sources (coal, oil and gas). The results show that, first, the reduction in global emissions intensity has coincided with a significant reduction in international inequality. Second, the bulk of this inequality and its reduction are attributed to differences between the groups of countries considered. Third, coal is the main energy source explaining these inequalities, although the growth in the relative contribution of gas is also remarkable. Fourth, the bulk of inequalities between countries and its decline are explained by differences in energy intensities, although there are significant differences in the patterns demonstrated by different groups of countries. JEL codes: D39; Q43; Q56. Key words: CO2 international distribution, inequality decomposition, CO2 emissions intensity
Resumo:
This paper describes petrologic and morphologic characteristics of fossil beaches submerged in the sector of the Costa Brava located between the Pals Beach and Blanes (Girona). These submerged beaches are composed of large-grain sandstone andconglomerate platforms, situated at a depth between 0.5 and 2.5 meters. These platforms are slightly inclinated towards the open sea. These deposits have been formed very recently, and date from Holocene, as noted by the presence of fragments of roman ceramics inside sandstone