Triploporella ? edgelli n. sp., a new Dasycladalean alga from the Lower Cretaceous of Lebanon

The Dasycladalean assemblage of the Jezzinian strata (uppermost Barremian–lowermost Aptian) of Lebanon consists of two organo‐genera and eight genera with eleven species, including eight Triploporellaceae. Although Triploporella marsicana (Praturlon, 1964) was reported by Saint‐Marc from the same interval, it is not found in our material. However, a lookalike, which is herein described as Triploporella ? edgelli n. sp., is identified. This new species has cyst‐containers within the primary segments of its laterals but, because it lacks calcified secondary segments, it is left in open nomenclature.     

Aptian bio-events—an integrated biostratigraphic analysis of the Almadich Formation, Inner Prebetic Domain, SE Spain

The Upper Barremian to Aptian Almadich Formation (Inner Prebetic Domain of the Betic Cordillera) is composed of hemipelagic sediments deposited on a distal carbonate ramp in the southern Iberian Palaeomargin. Within this facies we have found a thick interval of blue to black shales and marls that is interpreted as deposited under oxygen-depleted conditions. We think that this interval, dated as early Aptian, represents the local record of Ocean Anoxic Event 1a. The integrated biostratigraphic analysis of a section in the Almadich Formation, by means of planktonic foraminifera, calcareous nannofossils and ammonites, enables us to recognize most of the biostratigraphic units based on these three fossil groups and to correlate between them. The Sartousiana, Sarasini, Weissi, Deshayesi and Furcata (ammonite) Zones were identified for the Upper Barremian–Lower Aptian interval. By means of calcareous nannofossil biostratigraphy the Micrantholithus hoschulzii, Hayesites irregularis and Rhagodiscus angustus Zones, plus several additional biohorizons, were identified. A quantitative study performed on a set of 27 Lower Aptian samples has enabled the precise identification of the ‘nannoconid crisis’, the lower limit of which clearly precedes the main anoxic event, and its correlation with other bioevents. Planktonic foraminifera occur consistently throughout the Lower to Upper Aptian of the Cau section and are moderately well preserved. This fact allows us to use the most recent taxonomic framework, based on wall texture, to identify the Blowiella blowi, Schackoina cabri, Globigerinelloides ferreolensis, Globigerinelloides algerianus, Hedbergella trocoidea andTicinella bejaouaensis Zones. Coincident with the anoxic episode, the planktonic foraminiferal assemblages are composed of a significant number of forms with elongated chambers and/or tubulospines assigned to the genera Claviblowiella,Lilliputianella , Leupoldina and Schackoina. Most of the planktonic foraminiferal and nannofossil taxa are illustrated.     

Sedimentary record of explosive silicic volcanism in a Cretaceous deep-marine conglomerate succession, northern Antarctic Peninsula

Lower Cretaceous conglomeratic strata exposed on southern Sobral Peninsula were deposited on a deep‐marine apron in the back‐arc Larsen Basin close to its faulted boundary with the Antarctic Peninsula magmatic arc. The succession is dominated by amalgamated beds of clast‐supported conglomerate, which, together with minor intercalated sandstones, consist of varied, but largely basaltic to andesitic, volcanic material and clasts derived from the Palaeozoic–Triassic (meta)sedimentary basement of the arc. Most of the volcanic clasts are thought to have been derived from lithified volcanic successions or older synvolcanic deposits, rather than from sites of coeval eruption. These mixed‐provenance strata enclose a number of intervals, consisting mainly of inverse–normally graded conglomerate and graded–stratified pebbly sandstone, in which the sand fraction is dominated by crystals and vitric grains considered to have been redeposited in the immediate aftermath of explosive silicic arc volcanism. Like syneruption deposits on non‐marine volcaniclastic aprons, these intervals are more sand‐prone than the enclosing strata and appear to show evidence of unusually rapid aggradation. Plagioclase from one such interval has yielded ⁴⁰Ar/³⁹Ar ages concordant at ≈121 Ma, similar to those obtained from the non‐marine Cerro Negro Formation, deposited within the magmatic arc. It is suggested that the two successions can be viewed as counterparts, both recording a history of mainly basaltic to andesitic volcanism, punctuated by relatively infrequent, explosive silicic eruptions. Whereas the Cerro Negro Formation consists mainly of syneruption deposits, most of the volcaniclastic material delivered to the eruption‐distal, deep‐marine apron appears to have been derived by normal degradation processes. Only rare silicic eruptions were capable of supplying pyroclastic material rapidly enough and in sufficient quantities to produce compositionally distinct syneruption intervals.     

Biostratigraphic characterization by means of ammonoids of the lower Aptian Oceanic Anoxic Event (OAE 1a) in the eastern Iberian Chain (Maestrat Basin, eastern Spain)

It is now generally accepted that the Oceanic Anoxic Event 1a [OAE 1a] correlates with the lower part of the Leupoldina cabri planktonic foraminiferal Zone. Its calibration against the standard ammonite scale, however, seems to be more problematic. This is due, in part, to the fact that ammonites are scarce and/or of little diagnostic value from a biochronological viewpoint in the lower Aptian pelagic successions where the black shale horizons are better developed.We have been able to characterize OAE 1a geochemically in the relatively shallow water deposits of the eastern Iberian Chain (Maestrat Basin, eastern Spain), where ammonite faunas are rich. The interval corresponding to this event is dominated by the genera Roloboceras and Megatyloceras, accompanied by Deshayesites forbesi and Deshayesites gr. euglyphus/spathi. This assemblage is characteristic of the middle/upper part of the Deshayesites weissi Zone. The first occurrence of the species Deshayesites deshayesi (d'Orbigny), which marks the base of the overlying zone, takes place in our sections some metres above the OAE 1a interval.In the historical stratotype region of Cassis-La Bédoule (southern Provence Basin, southeastern France), the OAE 1a interval is also characterized by the presence of Roloboceras and Megatyloceras. Nevertheless, it has usually been correlated with the D. deshayesi Zone. In our opinion, this discrepancy is due to divergences in the taxonomic assignments of the deshayesitids present in these beds. In fact, the specimens attributed by French authors [Ropolo, P., Conte, G., Gonnet, R., Masse, J.P., Moullade, M., 2000. Les faunes d'Ammonites du Barrémien supérieur/Aptien inférieur (Bédoulien) dans la région stratotypique de Cassis-La Bédoule (SE France): état des connaissances et propositions pour une zonation par Ammonites du Bédoulien-type. Géologie Méditerranéenne 25, 167–175; Ropolo, P., Moullade, M., Gonnet, R., Conte, G., Tronchetti, G., 2006. The Deshayesitidae Stoyanov, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France), Carnets de Géologie / Notebooks on Geology Memoir 2006/01, 1–46.] to D. deshayesi and D. dechyi can be reinterpreted as belonging to D. forbesi.Following this reinterpretation, the Roloboceras beds (equivalent of OAE 1a) of Cassis-La Bédoule would also correspond to the D. weissi Zone. This age is additionally corroborated by data from southern England [Casey, R., 1961a. The stratigraphical palaeontology of the Lower Greensand. Palaeontology 3, 487–621; Casey, R., 1961b. A Monograph of the Ammonoidea of the Lower Greensand, part III. Palaeontographical Society, London, pp. 119–216], and by our recent observations in Le Teil (Ardèche Platform, southeastern France), where the Roloboceras faunas are also associated with Deshayesites consobrinus and Deshayesites gr. euglyphus, taxa that are characteristic of the D. weissi Zone.     

Aptian (Lower Cretaceous) biostratigraphy and cephalopods from north central Tunisia

Thick Aptian deposits in north central Tunisia comprise hemipelagic lower Aptian, reflecting the sea-level rise of OAE 1a, and an upper Aptian shallow marine environment characterized by the establishment of a carbonate platform facies. Carbon stable isotope data permit recognition of the OAE 1a event in the Djebel Serdj section. Cephalopods are rare throughout these successions, but occurrences are sufficient to date the facies changes and the position of the OAE1a event. Ammonite genera include lower Aptian Deshayesites, Dufrenoyia, Pseudohaploceras, Toxoceratoides and ?Ancyloceras; and upper Aptian Zuercherella, Riedelites and Parahoplites. Correlation of carbon isotope data with those of other Tethyan sections is undertaken together with the integration of planktonic foraminiferal data.     

Aptian palaeoclimates and identification of an OAE1a equivalent in shallow marine environments of the southern Tethyan margin: Evidence from Southern Tunisia (Bir Oum Ali section,Northern Chott Chain)

Alternations between siliciclastic, carbonate and evaporitic sedimentary systems, as recorded in the Aptian mixed succession of southern Tunisia, reflect profound palaeoceanographic and palaeoclimatic changes in this area of the southern Tethyan margin. The evolution from Urgonian-type carbonates (Berrani Formation, lower Aptian) at the base of the series, to intervals dominated by gypsum or detrital deposits in the remainder of the Aptian is thought to result from the interplay between climate change and tectonic activity that affected North Africa.Based on the evolution of clay mineral assemblages, the early Aptian is interpreted as having been dominated by slightly humid conditions, since smectitic minerals are observed. Near the early to late Aptian boundary, the onset of a gypsiferous sedimentation is associated with the appearance of palygorskite and sepiolite, which supports the installation of arid conditions in this area of the southern Tethyan margin. The evaporitic sedimentation may have also been promoted by the peculiar tectonic setting of the Bir Oum Ali area during the Aptian, where local subsidence may have been tectonically enhanced linked to the opening of northern and central Atlantic. Stress associated with the west and central African rift systems may have triggered the development of NW–SE, hemi-graben structures. Uplifted areas may have constituted potential new sources for clastic material that has been subsequently deposited during the late Aptian.Chemostratigraphic (δ¹³C) correlation of the Bir Oum Ali succession with other peri-Tethyan regions complements biostratigraphic findings, and indicates that a potential expression of the Oceanic Anoxic Event (OAE) 1a may be preserved in this area of Tunisia. Although the characteristic negative spike at the base of this event is not recognized in the present study, a subsequent, large positive excursion with δ¹³C values is of similar amplitude and absolute values to that reported from other peri-Tethyan regions, thus supporting the identification of isotopic segments C4–C7 of the OAE1a. The absence of the negative spike may be linked to either non preservation or non deposition: the OAE1a occurred in a global transgressive context, and since the Bir Oum Ali region was located in the innermost part of the southern Tethyan margin during most of the Aptian, stratigraphic hiatuses may have been longer than in other regions of the Tethys. This emphasizes the importance of integrating several stratigraphic disciplines (bio-, chemo- and sequence stratigraphy) when performing long-distance correlation.     

http://www.sciencedirect.com/science/article/pii/S167498711300090X

The Khami group within the petroliferous Zagros Basin of Iran includes the Surmeh, Hith, Fahliyan, Gadvan and Dariyan formations. The Dariyan Formation, previously known as Orbitolina limestone is very signif-icant as a reservoir rock in the Zagros Basin. In this study, the age of the Dariyan Formation is examined based on biostratigraphic and paleontological investigations. 236 m of Dariyan Formation sediments in the sections at Kuh-e Rahmat （north） and Nour-Abad （west） of Iran were selected to study its biostratigraphy. According to the lithostratigraphic investigations, the Dariyan Formation in these sections is subdivided into three： lower, middle and upper, which include thin-bedded to medium-bedded and massive lime-stone. Micropaleontologic study of the Dariyan Formation has led to the recognition of two biozones in the Nour-Abad area and one biozone in the Kuh-e Rahmat stratigraphic column. Diagnostic foraminifera in these sections are as follows： Globigerinel oides algerianus Cushman and Ten Dam, Globigerinelloides fer-reolensis Moullade, Globigerinelloides maridalensis （Bolli）, Globigerinelloides paragottisi Verga and Permoli Silva, Hedbergel a aptiana Bartenstein, Hedbergel a excelsa Longoria, Hedbergel a luterbacheri Longoria, Hedbergella occulta Longoria, Hedbergella ruka （Banner et al.）, Hedbergella similis Longoria, Hedbergella trocoidea （Gandolfi）, Muricohedbergella delrioensis （Carsey）, Pseudoplanomalina cheniourensis Sigal, Con-icorbitolina conica d＇Archiac, Iraqia sp., Mesorbitolina parva Douglass, Mesorbitolina pervia Douglass, Meso-rbitolina ovalis Gorog and Arnaud-Vanneau, Mesorbitolina subconcava Leymerie, Mesorbitolina texana （Roemer）, Mesorbitolina ovalis-pervia Cherchi and Schroeder, Debarina hahounerensis Fourcade et al., Marssonel a trochus （d＇Orbigny）, Nezzazata sp., Orbitolina sp., Textularia sp.     

New Material of Feilongus (Reptilia: Pterosauria) from the Lower Cretaceous Jiufotang Formation of Western Liaoning

Based on a new nearly naturally preserved skull and four cervical vertebrae of the pterosaur Feilongus sp. from the lower Cretaceous Jiufotang Formation of Beipiao, western Liaoning province, northeastern China, the diagnosis of Feilongus is amended. The revised diagnosis notes long, curved, needle-shaped teeth that are confined to the jaw far anterior to the nasoantorbital fenestra; posterior teeth that are slightly smaller than the anterior teeth; cervical vertebrae elongated with a ratio of length to width greater than 5; tooth number of about 78; and two cranial sagittal crests.     

High fidelity preservation of fossil insects from the Crato Formation (Lower Cretaceous) of Brazil

Fossil insects from the Lower Cretaceous (Aptian) Crato Formation of north-east Brazil are preserved as goethite replacements in laminated limestones of lacustro-lagoonal origin. They display remarkable degrees of morphological detail down to the macromolecular level in some examples. We document the fidelity of preservation and reveal an astonishing variety of morphological detail comparable in some instances with that found in amber inclusions.     

A new species of Vectiselachos (Chondrichthyes,Selachii) from the Early Cretaceous of southern England

Teeth of a new species of hybodont shark Vectiselachos (Chondrichthyes: Lonchidiidae) are described from the late Aptian (Early Cretaceous) of southern England. Vectiselachos gosslingi sp. nov. has very distinctive coarse striations that form raised ridges over the occlusal surfaces of the crown.