Upper Barremian-lower Aptian Urgonian-type platform carbonates from Ardèche yield a rich rudist fauna belonging to the families Requieniidae, Monopleuridae, Caprinidae, and Polyconitidae. The upper Barremian assemblage from the Ardèche river gorges consists of eighteen species, it conforms to the Rustrel fauna of the Monts-de-Vaucluse but contains a new genus Valclusella, and a new species of Bicornucopina, a genus unknown so far in Western Europe, whereas Mathesia darderi is identified for the first time in SE France. We define the "Saint-Montan limestones", of early Aptian age, as the uppermost member of the Urgonian Formation in this region. The corresponding Saint-Montan fauna is described for the first time: it contains twenty-five rudist species, of which eight are new and seventeen are inherited from the antecedent late Barremian Orgon and Rustrel fossil type localities. Of the eight new species, two are ascribed to earlier genera, i.e., Homopleura parva and Bicornucopina acuminata, three are assigned to a new genus, Myostyla ardescensis, while Valclusella valclusensis and Valclusella biconvexa preexisted in the late Barremian. Aside from inherited taxa, e.g., Pachytraga paradoxa, Praecaprina varians-gaudryi, Caprina douvillei, important novelties regard the Caprinidae, characterized by the appearance of probable new species of Pachytraga, P. aff. paradoxa, Offneria, O. aff. rhodanica, and three new species of Praecaprina: Pr. tubifera n. sp., Pr. paquieri n. sp., and Pr. vacua n. sp. The early Aptian p.p., therefore, coincides with the acme of the genus Praecaprina, SE France being unique in this respect. In the Saint-Montan fauna, up to about nine species from the Rustrel fauna are missing. The Saint-Montan rudist assemblage is unique, thus far, in SE France, even as the study of its composition is still in progress. It has a West European character, similar to that of its antecedent late Barremian one, and the succeeding late early Aptian Villaroya de los Pinares fauna from Spain, but the three have distinctive taxonomic compositions. The Saint-Montan stratigraphic succession is framed by two drowning boundary events. The taxonomic composition of its rudist assemblage fills a gap between the late Barremian and the late early Aptian faunas, and represents a distinctive episode in the Barremian-lower Aptian Urgonian-type rudist sequence of southern France and Spain, and possesses a significant biostratigraphic potential.

Two new species of the genus Horiopleura (Family Polyconitidae) are described from the Lower Cretaceous deposits of the Mediterranean Tethys margins. Horiopleura arabica comes from the lower Aptian Qishn Formation of southern Oman and Horiopleura helviorum, which occurs in the upper Barremian, Urgonian, Rustrel fauna but was primarily recorded in the lower Aptian deposits of Ardèche (SE France). In Horiopleura arabica the left valve projects dorsally off the commissural plane and the anterior myophore is a small crest, the right valve posterior myophore is a ledge; radial bands are weak but present. Horiopleura helviorum, the smallest species of the genus is characterized by a parietal lamellar anterior myophore on right valve. The two new species, are small and possess a domal left valve. They have a significant biostratigraphic and palaeobiogeographic potential. The new species illustrate a particular mode of arrangement of the anterior myophore on the right valve of Horiopleura, leading to a distinctive species grouping during the late Barremian-early Aptian. Our discoveries document a remarkable contemporaneous radiation of the Polyconitidae.

This study re-evaluates the Urgonian series in the Ardèche Gorges through detailed fieldwork and a re-examination of thin sections from six key cliff and road sections (Révaou–Serre de Tourre, Autridge, Rouveyrolle, Rouvière, Saint-Marcel, and Aiguèze). Two additional reference sections (Pont d’Arc and Mézelet), previously investigated by other authors, are incorporated for regional correlations. The main objective is to establish and correlate stratigraphic sequences of the Ardèche Gorges through comparison with the established Urgonian framework of southeastern France (Provence and the Subalpine Chains). Several emersion and drowning surfaces are recognised and tentatively correlated across the sections. An additional aim concerns the recognition and characterization of rudist faunas through the sucession. Facies changes point to a south-eastward trend toward more proximal environments during the deposition of the Urgonian limestones, challenging earlier interpretations that stacked these sections stratigraphically. Notably, the Mézelet section records a major hiatus at the top of the Urgonian succession, spanning the Barremian–Aptian boundary and directly overlain by the open-marine marls of the Chabert Formation. In contrast, the Aiguèze section preserves a continuous inner-platform succession across the same time interval and, for the first time ever, yields an unequivocal early Aptian rudist fauna (Saint-Montan fauna) across the entire southeastern French Urgonian-type domain. This discontinuity at Mézelet most likely reflects the latest Barremian eustatic sea-level fall, although a concomitant tectonic control cannot be ruled out.

The lower Aptian limestones of the Ardeche and Vaucluse regions (SE France) contain an assemblage of dasycladalean algae that, in great part, has not been described until now. The assemblage is dominated by large species belonging to the genera Triploporella, Dragastanella, and Salpingoporella. The paleontological study allowed the description of two new species: Salpingoporella vivariensis n. sp. and Similiclypeina hadrianii n. sp. The large dasycladaleans associated with caprinid rudists, characteristic of muddy (micritic) deposits, indicate a low water agitation that allowed the preservation of their delicate skeletons. The early Aptian dasycladalean flora studied here, including the new species, belongs to the West European Province. (c) 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Upper Barremian-lower Aptian Urgonian-type platform carbonates from Ard & egrave;che yield a rich rudist fauna belonging to the families Requieniidae, Monopleuridae, Caprinidae, and Polyconitidae. The upper Barremian assemblage from the Ard & egrave;che river gorges consists of eighteen species, it conforms to the Rustrel fauna of the Monts-de-Vaucluse but contains a new genus Valclusella, and a new species of Bicornucopina, a genus unknown so far in Western Europe, whereas Mathesia darderi is identified for the first time in SE France. We define the "Saint-Montan limestones", of early Aptian age, as the uppermost member of the Urgonian Formation in this region. The corresponding Saint-Montan fauna is described for the first time: it contains twenty-five rudist species, of which eight are new and seventeen are inherited from the antecedent late Barremian Orgon and Rustrel fossil type localities. Of the eight new species, two are ascribed to earlier genera, i.e., Homopleura parva and Bicornucopina acuminata, three are assigned to a new genus, Myostyla ardescensis, while Valclusella valclusensis and Valclusella biconvexa preexisted in the late Barremian. Aside from inherited taxa, e.g., Pachytraga paradoxa, Praecaprina varians-gaudryi, Caprina douvillei, important novelties regard the Caprinidae, characterized by the appearance of probable new species of Pachytraga, P. aff. paradoxa, Offneria, O. aff. rhodanica, and three new species of Praecaprina: Pr. tubifera n. sp., Pr. paquieri n. sp., and Pr. vacua n. sp. The early Aptian p.p., therefore, coincides with the acme of the genus Praecaprina, SE France being unique in this respect. In the Saint-Montan fauna, up to about nine species from the Rustrel fauna are missing. The Saint-Montan rudist assemblage is unique, thus far, in SE France, even as the study of its composition is still in progress. It has a West European character, similar to that of its antecedent late Barremian one, and the succeeding late early Aptian Villaroya de los Pinares fauna from Spain, but the three have distinctive taxonomic compositions. The Saint-Montan stratigraphic succession is framed by two drowning boundary events. The taxonomic composition of its rudist assemblage fills a gap between the late Barremian and the late early Aptian faunas, and represents a distinctive episode in the Barremian-lower Aptian Urgonian-type rudist sequence of southern France and Spain, and possesses a significant biostratigraphic potential.

During the Cretaceous, the gradual and extensive diversification of rudists led this group to colonise the carbonate platforms of tropical seas all over the world, structuring new ecosystems. The Albian genus Sellaea Di Stefano, 1889 has a worldwide distribution ranging from the Caribbean to Tibet, with maximum diversity centered in the Mediterranean province. This genus, recently studied in American faunas, is an important witness of the paleobiogeographical dynamics at work during this process of diversification, which generated significant endemism and helped characterise the paleobiogeographical provinces of the late Early Cretaceous. In order to add to our knowledge of this genus and the paleobiogeography of rudists, we report the existence of Sellaea in Cantabria, Spain. The middle and late Albian age is based on the presence of the ammonite Anahoplites Hyatt, 1900 and the rudists Eoradiolites jumillensis Masse, Fenerci-Masse, Vilas & Arias, 2007 and Caprina choffati Douvill & eacute;, 1898. Specimens have been identified as Sellaea stryx (Di Stefano, 1889), a species without pallial canals that belongs to the Mediterranean clade, a sister group to the American Sellaea. After describing in detail the localities where the specimens were found, we show the relevance of the presence of Sellaea stryx in the Cantabrian Albian faunas from a biostratigraphic point of view. We also discuss the impact of the presence of these faunas from a paleobiogeographical point of view.

The genus Archaeoradiolites, discovered for the first time in two regions of Romania, the Southern Carpathians and the Apuseni Mounts, is represented by A. hispanicus and A. primitivus, two chronospecies first described from Southern Spain. The genus Archaeoradiolites whose definition tends to focus on the outer shell microstructure with radially arranged branching walls, is emended: it has true plate The Romanian radiolitid-bearing beds are assigned to the upper Aptian. The association of radiolitids with a coral community assumed to be mesophotic, i.e. ciralittoral is unusual and transient infralittoral conditions in an overall circalittoral regime are assumed Archaeoradiolites appears mainly as a North Tethyan Mediterranean taxon. Its spatial extent, from the Pontides, southern France and southern Spain tend to weaken or erase, in the late Aptian, the antecedent bipartite palaeobiogeographic division of Europe, an event correlated with the mid-Aptian crisis.(c) 2023 Published by Elsevier Ltd.

A new species of Pachytraga (family Caprinidae) is described from the Fore<^>t de Coulmes (Northern Vercors, Subalpine region of SE France) and dated from the Taveraidiscus hugii- Nicklesia nicklesi ammonite Zones (lowermost Barremian). Pachytraga gracilis sp. nov. has an undivided posterior myocardinal cavity on the left valve and an anterior myophore supported by a single row of rectangular canals. The right valve bears a row of anterior canals, a partitioned posterior perimyophoral cavity and a network of minute pallial canals on the dorsal side. The new species represents an evolutionary link in between the Hauterivian Pachytraga tubiconcha and the Late Barremian-early Aptian Pachytraga paradoxa, so shortening the West European Barremian Lazarus phase of the genus Pachytraga. The possibility of a Barremian p.p. ecological rather than geographical refuge is proposed. We consider the new species as a potential biostratigraphic marker of the West European lowermost Barremian. It is the oldest member of canaliculated Caprinidae. Number of traits of Pachytraga gracilis sp. nov. (shape, mode of canaliculation), are absent in its assumed descendant P. paradoxa, but present in other advanced taxa, Praecaprina, Caprina, hence the new taxon was a precursor in more ways than one.(c) 2023 Published by Elsevier Ltd.

Barremian-lower Aptian requieniid rudists from the Southern Carpathians and the Apuseni Mountains, in Romania, are represented by four new species of the genus Matheronia Munier-Chalmas: Matheronia dacica, Matheronia nerae, Matheronia carinata and Matheronia silvaeregis. In the study stratigraphic interval these species possess a potential biostratigraphic value. Their evolution trough time is essentially characterized by shell size increase. Matheronia looks restricted to the North Mediterranean Tethyan margin and the new Romanian species are interpreted as markers of the Carpatho-Cimmerian rudist province.

A new species of the genus Pachytraga, P. carpathica sp. nov., is described from the Mediterranean Tethyan domain, identified in Barremian platform carbonates of Romania. The species was recorded in the Apuseni Mountains and the Carpatho-Balkan region in beds with a lower Barremian micropalaeontological assemblage. The evolutionary character of the new taxon is relatively primitive but represents a mosaic of the antecedent Pachytraga tubiconcha and succeeding Pachytraga paradoxa. This discovery potentially fills an evolutionary gap between the two former stratigraphically disjunct species, but the emergence of Pachytraga paradoxa remains problematic.

Sellaea is a key genus for understanding the expansion of rudists in the middle Cretaceous. Its incursion into the Americas in the Albian is open to taxonomic debate, as several researchers have hypothesised that the American Sellaea belongs to a new genus. A taxonomic revision with analysis of new material from the Edwards Formation (Texas, USA) coupled with a cladistic analysis using three-taxon analysis allows us to redefine the genus Sellaea. The phylogeny reveals two distinct endemic groups, one belonging to the Mediterranean province, and one to the Caribbean province. However, the involved synapomorphies, related to the left valve posterior cavity, the shell margin, and the outline, are not sufficient to create a new genus. The character related to pallial canals is the only one to be homoplastic in the phylogeny of Sellaea. The presence of canals is therefore a variable character state within the genus. The genus is redefined accordingly, allowing the relocation of several species originally assigned to Caprotina, including species that lack pallial canals and species with unknown right valves. Sellaea minuta is the only species retained over the four Sellaea described from the Americas. The redefined genus Sellaea is Albian-Cenomanian in extent, with the incursion of a single species into North America in the Albian.

The Carpatho-Cimmerian bioprovince is a Barremian–lower Aptian entity. Its definition based on the coexistence of two calcareous algae and a foraminifera, is well supported by a distinctive rudist assemblage. Thirteen species: Requienia zlatarskii, Lovetchenia lovetchensis, Lovetchenia drinovi, Lovetchenia stratechi, Toucasia petersi, Parapachytraga gigantea, Paragyropleura paquieri, Debrunia ? dibrariana, Debrunia ? kafanensis, Homopleura balkanica, Homopleura ? minima, Homopleura? gigantea and Bicornucopina petersi are characteristic, endemic members of this bioprovince. The Carpatho-Cimmerian bioprovince shared some taxa with Western Europe and Apulian biomes. The Carpatho-Cimmerian rudist assemblage extends from Hungary, Romania, Bulgaria, Slovakia, Ukraine, Southern Russia, Northern Turkey, Armenia, Azerbaidjan and probably Turkmenistan. The South Bohemian shelfal discontinuity between the Western European and the Balkanic regions, accounts well for the dissimilarity of the corresponding faunas.

The "Agriopleura event", which expresses the regional extinction, in northwestern Europe, of the rudist genus Agriopleura, is associated with environmental and biological changes. This event marks the boundary between two distinctive late Barremian regional rudist assemblages, the pre-event Brouzet-les-Alès and post-event Orgon faunas. The succeeding Palorbitolina episode is coeval with a rudist eclipse. The ensuing Rustrel fauna identifies the phase of post-extinction recovery. The last occurrence of Agriopleura, the stem genus of the Radiolitidae, coincides with the extinction of 41% of the pre-event Requieniidae and Monopleuridae. The recovery phase is characterized by new species and a low extinction pattern. This phase is marked by a burst of speciation, in part indigenous and in part due to immigrants i.e. Caprinidae. The key morphotypes, clingers, elevators and recumbents record contrasting changes in specific diversity, clingers being dominant due to the substantial diversity of Requieniidae and Monopleuridae. During the extinction event elevators decrease and suffered a reduction in size, large size species being selectively eliminated. The entry of the Caprinidae identifies the recovery phase and accounts for size increase and an important contribution of recumbent. The main agent of the extinction, combines cooling, anoxia, platform exposure and a trophic factor assumed to account for the selective removal of the elevators. A dual partition in feeding behavior of clingers and elevators is suggested: elevators exploiting the phytoplankton flux and the re-suspended bottom biodeposits; and clingers feeding on the benthic boundary layer. Significant community changes are associated with Agriopleura extinction and its aftermath, which clearly respond to changes in taxonomic composition. Elevator dominated communities with the Agriopleura are replaced by polytaxic requieniid rich communities then by caprinids. The Palorbitolina episode, records a trophic peak, cooling and a deepening trend. The recovery phase mainly records an aragonitic pulse coupled with temperature increase.

This contribution provides new insights on the taxonomic composition, diversity and ecological aspects of the poorly explored non-rudist Barremian bivalves occurring in the Urgonian-type carbonate platforms of southeast France and the neighbouring areas. Our inventory documents the occurrence of 8 orders having both infralittoral and circalittoral taxa; namely Arcida, Mytilida, Pectinida, Ostreida, Trigoniida, Carditida, Cardiida and Lucinida. By contrast, the so-called rudist order Hippuritida, which is classically considered to be dominant in those Urgonian-type platforms, is unique and only contains infralittoral taxa. We identified 46 genera and 73 species of infralittoral non-rudist bivalves, which are dominated by the orders Pectinida and Mytilida. This is to be contrasted to the less diverse order Hippuritida including only 13 genera and 43 species during the Barremian. The total diversity of infralittoral bivalves is, therefore, of 58 genera and 116 species at that time. Non-rudist bivalves are dominated by two main functional groups: epibyssate and shallow infauna, whereas clingers and elevators are the dominant rudist morphotypes. Three main assemblages of non-rudist bivalves are identified, each possessing distinctive taxa, diversities and proportions of functional groups with respect to the three main type of facies along a proximal–distal gradient (rudist, coral, and calcarenite facies). The highest diversity of non-rudist bivalves occurs in rudist-free or rudist-poor infralittoral areas adjacent to rudist clusters; only few of them were companions of rudists and associated into the corresponding community. Non-rudist bivalves have a higher diversity than rudists even if their physiognomic and sedimentologic roles are much more limited. Rudist furthermore grow as constratal sediment dwellers, non-reef builders and are powerful agents of “niche construction” by contrast to normal bivalves.

The detailed sedimentological and biostratigraphic study of the upper Aptian-Albian series in the Chott area, southern Central Tunisia, leads to the identification of several, well-dated depositional sequences. The upper Aptian sequences are marked by very shallow marine, first partly evaporitic, then mainly clastic deposits. The last sequence yielded latest Aptian ammonites (H. jacobi zone). The Aptian-Albian boundary is assumed to be marked by a long-lasting hiatus, and by the abrupt change from clastic to carbonate deposits. The overlying "Knemiceras Beds" express the Albian transgression, and comprise four depositional sequences. New findings of ammonites allow to date these beds to the lower Albian (D. mammillatum superzone), and to correlate the four sequences with those defined in Central Tunisia. Five distinct morphologies of Knemiceras sp. are recognized in the "Knemiceras beds". Because of their stratigraphic position, the overlying massive shelf carbonates (Radhouane Member) are ascribed to the uppermost lower Albian (T. camatteanum and L. pseudolyelli zones), and correlated with the Allam Limestone of Central Tunisia. This carbonate series is capped by a major discontinuity, correlated with the middle Albian discontinuity known in Central Tunisia. The ammonites and rudists fauna are pre-sented and illustrated.(c) 2022 Elsevier Ltd. All rights reserved.

在碳酸盐沉积体系(CSS)特别是浅水碳酸盐岩台地沉积中,测试了一种基于地层正演模拟的定量层序地层学方法.除非裁剪出清晰的三维(3D)和二维(2D)地层几何图形或通过地震数据成像,否则须假设一个代表可容空间变化速率与沉积速率(A'/S')之比变化的单一因素可以描述地质历史中盆地规模的复杂3D碳酸盐岩地层结构,这样才能重建碳酸盐岩的3D层序地层结构.本项研究证明,尽管采用了独特的可容空间变化曲线和时间恒定的碳酸盐岩产率,但理论上A'/S'的保存(被认为是层序地层学的基本参数)在单个碳酸盐岩台地地层结构中是不完整的,且在空间上是可变的.保存在地层记录中的表观A'/S'层序地层学参数与控制CSS地层响应的实际A'/S'参数是有区别的.鉴于可能会形成同时代水体向上变浅和加深的层序,所以,在可容空间总体增加期间,前积和退积的几何形态在时间上可能是等效的.一维表观A'/S'在近端和远端之间不具备稳定的可对比性,而且没有具特定意义的地层结构.这是沿台地剖面碳酸盐岩产率空间变化和同步变化的直接结果.这些结果表明,碳酸盐岩沉积柱(包括碳酸盐岩储层)的构建不能简单地建立在沿台地-斜坡沉积剖面的稀疏和远端位置的标准层序地层对比基础上.层序地层对比的局限性和A'/S'速率的不确定性可通过实际的CSS案例研究(法国南普罗旺斯地区下白垩统Urgonian台地)解决.提出了一种基于地层正演模拟的定量碳酸盐岩层序地层学工作流程.

The eastern Taurides yield an early Aptian rudist fauna including Agriopleura libanica and Offneria murgensis, two key members of the Arabo-African biome, reported for the first time in Turkey. The presence of this assemblage which closely resembles that of the Shu'aiba Formation of Saudi Arabia, Oman and the United Arab Emirates, fills a distributional, geographical gap between its Arabian, North African and Apulian occurences. The rudist fauna and the composition of the associated micropalaeontological elements suggest an early Bedoulian age and a close palaeogeographic proximity with the regional outer platform margin. The presence in the Taurides of an Arabo-African fauna is consistent with the palaeotectonic placement of the Anatolides-Taurides in between the Arabian promontory and the peri-Adriatic zone.

The wide range of wall microstructures observed in the test of calcitic Foraminifera is probably unequalled in nature, and contrasts strikingly with the rather homogeneously radial walls of hitherto examined aragonitic foraminifers, be they tubular or multichambered. But do we truly know the actual wall microstructural variability in aragonitic foraminifers? Aragonite is indeed extremely rarely preserved in the fossil record and seldom tested on modern forms. The present study introduces four new genera and species of planispiral to high trochospiral aragonitic multichambered Foraminifera (Incompositus involutus gen. et sp. nov., Krivajella krivaja gen. et sp. nov., Tenuiscolumna evoluta gen. et sp. nov. and Falsotrochosiphonia teres gen. et sp. nov.) discovered in a Berriasian level of the Krivaja Valley, Bosnia and Herzegovina. Their original, aragonitic wall is exceptionally well preserved and dominantly displays a singular microstructure, made of diversely oriented, inequigranular bundles of original aragonite crystals. Such a structure, reminiscent to some extent of that observed in various calcitic foraminifers (Miliolida, Fusulinida, granulate Rotaliida), had never been recognized as such or described in detail before. The existence of an unfamiliar wall type in morphologically distinct multichambered aragonitic foraminifers not only questions the monophyly of the order Robertinida but also evolutionary paths in the entire Phylum. We here demonstrate that the newly described forms are part of a lineage that experienced a long but concealed evolutionary history. It is time to look at the foraminiferal record with new eyes as several aragonitic groups may have eluded our scrutiny.

The Subalpine Urgonian platform provides seismic-scale outcrops of interest to constrain the depositional organisation of Lower Cretaceous carbonate systems. Revising the biostratigraphy using ammonites, rudists, calcareous algae and orbitolinids and establishing regional stratigraphic correlations between the Gresse-en-Vercors cliff and the Plateau de Glandasse provide a new vision regarding the Urgonian platform stratigraphic architecture of the southern Vercors. The rudist-dominated inner-platform series cropping out in the northern Gresse-en-Vercors cliff grades laterally southward into the bioclastic-dominated Glandasse Formation (defined in the Plateau de Glandasse series). Our new correlations contradict with the Grenoble University's conceptual platform model which considered the Glandasse Formation as rudist-poor lowstand deposits formed in the southern Vercors and sealed by the transgressive Urgonian limestones formation. Our interpretation better conforms to the Geneva University's conceptual model, suggesting that the Glandasse and Urgonian limestones formations should be regarded as stratigraphic equivalents. Further investigations are needed to address the stratigraphic evolution and controlling mechanisms of the regional Urgonian system at the regional scale.

Montlivaltia multiformis Taula (Scleractinia, Faviina, Montlivaltidae), formerly reported from the Carpatho Balkanic domain is described from Lower Aptian beds of the Prebetic Domain (SE Spain). Taxonomic attributes include the organisation of radial elements, septal trabeculae, carinae and endothecal elements while the external morphology of the coralla is fairly variable. The sedimentological context suggests a circalittoral environment also supported by palaecological features of the surrounding fauna. Owing to its stratigraphic position in the Carpatho-Balkanic region and in Spain, Montlivaltia multiformis appears as a potential marker for both shallow carbonate or outer shelf settings of the Lower Aptian Tethys European margin.