Oxfordian and Kimmeridgian "Aspidoceras" in the Mediterranean. A methodological approach

In this study we present a contrastive analysis of the Null Hypothesis, established as the methodological basis for the evolutive investigation of Mediterranean "Aspidoceras" (Checa & Olóriz, 1985). This contrast is carried out using new data, and is part of a research programme which has been carefully planned. Paleogeographic, sedimentological. stratigraphic and palcobiological considerations have provided new evolutive models which in turn lead to a structural reorganization of thc Null Hypothesis. In this new structure, the Basic Evolutionary Conformations are no longer considcred as mere morphological groupings, the result of a direct reading of thc fossil record. In this way we propose morphological blocks, representing evolutive units which can be related to one another.En el presente trabajo se lleva a cabo un análisis contrastador de la Hipótesis Nula establecida como base metodológica para la investigación evolutiva de los"Aspidoceras" mediterráneos (Checa & Olóriz, 1985). Esta contrastación se lleva a cabo integrando nuevos datos y forma parte de un programa de investigación cuidadosamente planificado. Las diversas consideraciones paleogeográficas, sedimentológicas, estratigráficas y paleobiológicas han proporcionado nuevos modelos evolutivos que suponen una sustancial reorganización estructural de la Hipótesis Nula. En esta estructuración, las Configuraciones Evolutivas Básicas no son consideradas como meros grupos morfológicos, resultado de una lectura del registro fósil, sino que constituyen unidades evolutivas que pueden, por tanto, relacionarse entre sí

Alometrías intertaxónicas y ontogenéticas entre el área del septo y el volumen del fragmocono en cefalopodos con concha espiral actuales y extintos

La interpretación funcional del replegamiento periférico de los septos de los ammonoideos constituye todo un reto dada la inexistencia de representantes actuales del grupo y, por consiguiente, la imposibilidad de experimentación directa. Por tal motivo las líneas de evidencia se han de basar en gran medida en comparaciones con otros cefalópodos camerados actuales. En este trabajo se comparan las alometrías ontogenéticas que siguen el área septal respecto al volumen del fragmocono en cefalópodos con concha espiral (interna o externa) con las obtenidas para ammonoideos adultos del Jurásico tardío. Las similitudes entre los coeficientes alométricos indican que el aumento de superficie que supone replegar los septos no aparenta ser muy diferente en las primeras etapas del crecimiento de los ammonoideos del de otros cefalópodos con concha espiral. Por el contrario, las discrepancias con los coeficientes alométricos para los ammonoideos adultos parecen apuntar a que la complejidad septal no se alcanza por una mera extrapolación de la ontogenia.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The Transversarium-Bifurcatus Zone boundary at Rocha (Peral area, East-Central Algarve, Portugal)

This paper represents the first detailed study of the Transversarium-Bifurcatus Zone boundary in the Algarve. The boundary studied in the Peral area is associated with a stratigraphic discontinuity, whose hiatus partially affects the Transversarium-Bifurcatus Zones. A discontinuity was also recognized in the Bifurcatus-Birnammatum Zone boundary, which can be correlated with the traces of a Type II unconformity, which separates cycles 4.3-4.4 in HAQ et al. (1987), present on the South Iberian palaeomargin. An analysis was made of the ecostratigraphic evolution in the interval between the uppermost Transversarium Zone and the lower part of the Bimammatum Zone on the basis of the faunal spectra obtained. We conclude that ammonites are the most tolerant cephalopods to the ecological stress caused by the increase of inflows and the decrease of the shelf's ecospace. Benthic fauna decreased considerably in these conditions. A relatively abundant and diversified fauna ofDichotomoceras is noteworthy among the ammonites collected, as this genus was previously little known in the Algarve

Foraminiferal assemblages as palaeoenvironmental bioindicators in Late Jurassic epicontinental platforms: relation with trophic conditions

Foraminiferal assemblages from the neritic environment reveal the palaeoecological impact of nutrient types in relation to shore distance and sedimentary setting. Comparatively proximal siliciclastic settings from the Boreal Domain (Brora section, Eastern Scotland) were dominated by inner−shelf primary production in the water column or in sea bottom, while in relatively seawards mixed carbonate−siliciclastic settings from the Western Tethys (Prebetic, Southern Spain), nutrients mainly derived from the inner−shelf source. In both settings, benthic foraminiferal assemblages increased in diversity and proportion of epifauna from eutrophic to oligotrophic conditions. The proximal setting example (Brora Brick Clay Mb.) corresponds to Callovian offshore shelf deposits with a high primary productivity, bottom accumulation of organic matter, and a reduced sedimentation rate for siliciclastics. Eutrophic conditions favoured some infaunal foraminifera. Lately, inner shelf to shoreface transition areas (Fascally Siltstone Mb.), show higher sedimentation rates and turbidity, reducing euphotic−zone range depths and primary production, and then deposits with a lower organic matter content (high−mesotrophic conditions). This determined less agglutinated infaunal foraminifera content and increasing calcitic and aragonitic epifauna, and calcitic opportunists (i.e., Lenticulina). The comparatively distal setting of the Oxfordian example (Prebetic) corresponds to: (i) outer−shelf areas with lower nutrient input (relative oligotrophy) and organic matter accumulation on comparatively firmer substrates (lumpy lithofacies group) showing dominance of calcitic epifaunal foraminifera, and (ii) mid−shelf areas with a higher sedimentation rate and nutrient influx (low−mesotrophic conditions) favouring potentially deep infaunal foraminifers in comparatively unconsolidated and nutrient−rich substrates controlled by instable redox boundary (marl−limestone rhythmite lithofacies).This research was carried out with the financial support of projects CGL2005−06636−C0201 and CGL2005−01316/BTE, and University of Oslo, Norway−Statoil cooperation. M.R. holds a Juan de la Cierva grant from the Ministry of Science and Technology of Spain

Open questions in utility theory

Throughout this paper, our main idea is to explore different classical questions arising in Utility Theory, with a particular attention to those that lean on numerical representations of preference orderings. We intend to present a survey of open questions in that discipline, also showing the state-of-art of the corresponding literature.This work is partially supported by the research projects ECO2015-65031-R, MTM2015-63608-P (MINECO/ AEI-FEDER, UE), and TIN2016-77356-P (MINECO/ AEI-FEDER, UE)

Contribución del análisis icnológico en la interpretación del origen de la rítmita margoso-calcárea de edad Kimmeridgiense inferior (Zona Platynota) en el Prebético Central

In the Central Prebetic the sediments of Early Kimmeridgian age (Platynota Chron) are represented by rhyth¬mic successions which are make up by marls, marly limestones and limestones. In the context of an integrated research programme and in order to analyze the sedimentary cyclicity It is proved the significance of ichnologic studies to reveal the existence of secondary overprint which determines the location of the boundary in marly- limestone couplets as they are recognizable at the outcro

The Oxfordian-Kimmeridgian boundary in the Puerto Lorente section (External Prebetic) revisited

In the Puerto Lorente section at the Sierra de Cazorla (External Prebetic), the uppermost Oxfordian is made up of limestones with recognizable traces of increasing condensation. O verlayin gare marls, marly-limestones and limestones of the Lower Kimmeridgian. The surface boundary between the Oxfordian and the Kimmeridgian has been traditionally referred to the cephalopod rich “hardground" which precedes deposition of the lowerm ost Kimmeridgian marls. Nevertheless, careful studies on this surface allowed us to identify rare specimens of Sutneria platynota (REINECKE) and therefore to improve the previous biostratigraphic interpretations. The obtained data will be valuable for the updated interpretation of the eco-sedimentary evolution in epicontinental areas of the Southlberian paleomargin around the Oxfordian-Kimmeridgian boundar