Lower Aptian Rudist Faunas (Bivalvia, Hippuritoidea) from Croatia

Lower Aptian rudist faunas from Croatia consist of Requienia? zlatarskii PAQUIER, Toucasia sp., Agriopleura sp., Glossomyophorus costatus MASSE, SKELTON & SLISKOVIC, Himeraelites sp. and Offneria sp. This assemblage has a clear Southern Tethyan (Arabo–African) significance and typifies the Early Aptian. Faunas from the interior of the Adriatic Carbonate Platform in Istria are dominated by Requieniidae while those from the northeastern area in the vicinity of Tounj–Ogulin, close to the platform margin, exhibit a higher diversity and include, beside requieniids, Caprinidae, Caprotinidae and Monopleuridae, in conjunction with evidence of open marine conditions

Late Aptian rudist faunas from the Zonguldak region, western Black Sea, Turkey (taxonomy, biostratigraphy, palaeoenvironment and palaeobiogeography)

In the western Black Sea region of Turkey (Zonguldak area), Late Aptian rudist-bearing carbonates (the Cengellidere Formation) yielded the following fauna: Toucasia gr. catinata-lonsdalei, Pseudotoucasia catalaunica, Polyconites verneuili, Horiopleura almerae, Eoradiolites plicatus and Eoradiolites sp. This assemblage dates the Gargasian and has a broad Mediterranean palaeobiogeographical significance. Because typical African elements are lacking, it is ascribed to the European Province, in agreement with palaeotectonic regional reconstructions. The rudist communities thrived on a mixed, carbonate-siliciclastic, coastal ramp facing a basin corresponding to the modern Black Sea. This mode of occurrence contrasts with the classical Urgonian-type flat, platform settings of wide extent. (C) 2002 Elsevier Science Ltd. All rights reserved

Late Aptian-Albian primitive Radiolitidae (bivalves, hippuritoidea) from Spain and SW France

The late Aptian-Albian radiolitid taxa, Praeradiolites cantabricus (Douville´) and Praeradiolites ibizanus Astre, from SW France and Spain, are transferred to Eoradiolites. Eoradiolites jumillensis nov. sp. is described from southern Spain, while the so-called ‘‘Sphaerulites cantabricus’’ sensu Toucas (1907) is moved to Praeradiolites and may be of Late Cretaceous age. The Eoradiolites cantabricus group of species is mainly Clansayesian-early Albian in age and possesses an advanced evolutionary status, mainly regarding shell size and cellular structure. Praeradiolites may have been derived from Eoradiolites jumillensis nov. sp. through paedomorphosis while Eoradiolites cantabricus may have been the source for Sphaerulites. Our study shows that the names Sphaerulites and Praeradiolites cannot be applied to pre-Cenomanian Radiolitidae and that Eoradiolites was the foremost genus in Late Aptian-Albian times in terms of species biodiversity. The Eoradiolites cantabricus group is restricted to the northwestern Mediterranean Tethyan margin

Earliest Aptian Caprinidae (Bivalvia, Hippuritida) from Lebanon

Abstract: The presence in Lebanon of Offneria murgensis and Offneria nicolinae, two characteristic components of the Early Aptian Arabo-African rudist faunas, fills a distributional gap of the corresponding assemblage between the Arabic and African occurrences, on the one hand, and the Apulian occurrences, on the other hand. This fauna bears out the palaeogeographic placement of Lebanon on the southern Mediterranean Tethys margin established by palaeostructural reconstructions. The associated micropaleontological elements suggest an earliest Aptian age (early Bedoulian) for the Offneria murgensis -O. nicolinae assemblage found in the "Falaise de BLANCHE" stratigraphic interval, instead of a late Early Aptian age as proposed for most of the peri-Adriatic and Middle East occurrences recognized so far. These caprinid specimens are characterized by relatively modest sizes, moreover other rudists commonly part of the assemblage are lacking. The dominance of caprinids in the study area suggests a distal platform setting, i.e., close proximity to the platform edge. Cette faune confirme la position paléogéographique du Liban sur la marge méditerranéenne téthysienne méridionale telle que présentée dans les reconstitutions de la tectonique des plaques. Les éléments micropaléontologiques associés suggèrent un âge Aptien basal (Bédoulien inférieur) pour l'association Offneria murgensis -O. nicolinae provenant de l'intervalle stratigraphique de la "Falaise de BLANCHE", au lieu d'un âge Aptien inférieur non basal comme ce qui est proposé pour la plupart des sites périadriatiques et moyen-orientaux connus jusqu'à pré-sent. Les exemplaires de ces caprinidés sont caractérisés par des tailles relativement modestes ; de plus les autres rudistes faisant couramment partie de ces associations sont ici absents. La prédomi-nance des caprinidés dans la région étudiée suggère un environnement distal sur la plate-forme, voire une proximité immédiate de sa bordure

Late Aptian-Albian primitive Radiolitidae (bivalves, hippuritoidea) from Spain and SW France

The late Aptian-Albian radiolitid taxa, Praeradiolites cantabricus (Douvillé) and Praeradiolites ibizanus Astre, from SW France and Spain, are transferred to Eoradiolites. Eoradiolites jumillensis nov. sp. is described from southern Spain, while the so-called “Sphaerulites cantabricus” sensu Toucas (1907) is moved to Praeradiolites and may be of Late Cretaceous age. The Eoradiolites cantabricus group of species is mainly Clansayesian-early Albian in age and possesses an advanced evolutionary status, mainly regarding shell size and cellular structure. Praeradiolites may have been derived from Eoradiolites jumillensis nov. sp. through paedomorphosis while Eoradiolites cantabricus may have been the source for Sphaerulites. Our study shows that the names Sphaerulites and Praeradiolites cannot be applied to pre-Cenomanian Radiolitidae and that Eoradiolites was the foremost genus in Late Aptian-Albian times in terms of species biodiversity. The Eoradiolites cantabricus group is restricted to the northwestern Mediterranean Tethyan margin.Our field investigation in southern Spain have been founded by the Ministerio de Ciencia y Tecnologia of Spain, number of project: REN2001-1067/GLO (Aplicacion de tecnicas del analisis de cuencas sedimentarias en el uso no destructivo del patrimonio natural en al Prebetico oriental. El altiplano de Jumilla-Yecla). At the Université de Provence, we have benefited from the technical assistance of A. Arnoux. Fruitful discussions with L. Villiers (Université de Provence, Marseille)Peer reviewe

Depositional biofacies model for post-OAE1a Aptian carbonate platforms of the western Maestrat Basin (Iberian Chain, Spain)

Two well exposed platform successions of late Early Aptian age developed in the central part of the Galve sub-basin of the Maestrat Basin: the highstand 'Camarillas-El Morrón' platform, and the succeeding 'Las Mingachas' small lowstand platform, built out downslope in the former basin. Both platforms had a flat-topped non-rimmed depositional profile, showing similar platform-top to slope biofacies, which are described here in both qualitative and quantitative terms. The proximal platform top succession is characterized by a Toucasia-dominated rudist association. The margins of the two platforms consist of massive limestone characterized by a Polyconites-dominated association, in which clusters of Polyconites hadriani in life position are joined by both branching and domal corals, as well as the oyster-like Chondrodonta and nerineid gastropods. In Las Mingachas platform, where the massive rudist- and coral-rich platform limestones pass laterally into the slightly more marly and recessive clinoforms of the upper slope facies, Polyconites is especially abundant. Basinwards these slope deposits pass into basinal marls with orbitolinids and ammonoids. The distribution of the two distinct rudist associations recognized here is attributed to the different environmental tolerances of the rudists with respect to such factors as current regime and rate of sedimentation. The prevalence of polyconitids, in place of caprinids, in these late Early Aptian platform margin facies makes a striking contrast with older, earliest Aptian platforms