On the occurrence of the ammonite aptychi Lamellaptychus cf. rectecostatus (Peters, 1854) from the Ogrodzieniec quarry (southern Poland)

The largely Kimmeridgian-Tithonian (Late Jurassic) aptychus Lamellaptychus rectecostatus (Peters, 1854) is considered to represent the jaw apparatus of the ammonite superfamily Haploceratoidea (Family Oppeliidae). However, here, from the Ogrodzieniec quarry (southern Poland), we present its unusual allochthonous occurrence embedded in a perisphinctid, Perisphinctes (Kranosphinctes) sp., and co-occurring with a late early Oxfordian Cordatum Subzone (Cordatum Zone) ammonite assemblage. The assemblage includes Cardioceras (Cardioceras) cf. cordatum (Sowerby), Neocampylites delmontanus (Oppel), Lissoceratoides erato (d’Orbigny), Bukowskites distortus (Bukowski), Trimarginites cf. arolicus (Oppel), Glochiceras sp., Holcophylloceras zignodianum (d’Orbigny) and Euaspidoceras (Euaspidoceras) perarmatum (Sowerby).     

Contribution à la connaissance des bivalves du Turonien d’Owendo dans le bassin côtier nord gabonais

The study of bivalves collected from Turonian deposits of Owendo region, within Gabonese coastal north basin, allows to identify 9 species belonging to 9 genera: Aphrodina dutrugei (Coquand 1862), Brachidontes eoexustus Klein and Ferreira 1979, Crassatella cf. pyrenaica d’Orbigny 1843, Entolium exilis (Reuss, 1854), Exogyra sp., Lopha sp., Mytilus cf. lineatus d’Orbigny 1844, Pholadomya adversa Riedel 1932 and Rastellum sp. Excepted A. dutrugei and P. adversa, which are known in Turonian localities of Gabon, other species are found here for the first time in Gabonese coastal basin. This is the same for genera named Brachidontes Swainson 1840, Entolium Meek, 1865 and Mytilus Linnée 1758. In Gabonese coastal basin, the stratigraphic and geographic ranges of the Crassatella genus are extended in Turonian and Owendo region respectively. The bivalve assemblage is dominated by specimens of Aphrodina genus. The bivalve specific diversity of Owendo region increase from 3 to 12 species.     

Brittle stars from the upper Cenomanian of the Preafrican platform: First ophiuroid remains for the Cretaceous of Algeria

While Late Cretaceous ophiuroids are relatively well known in Europe, these faunas have been much less studied in North Africa. With the exception of some Tunisian assemblages preliminary described at the turn of the 21st century, nothing is known about the Cretaceous brittle stars of the southwestern Tethyan margin. The present paper seeks to bring the first data about hitherto unknown ophiuroids recently found in the early upper Cenomanian succession of the eastern side of the Preafrican trough (Menaguir section, Algeria). This “community” of brittle stars comprises at least eight species. Most of them are probably new, but have not been formally named here. These are representatives of the families Hemieuryalidae, Amphiuridae, Ophiodermatidae, Ophiacanthidae, Ophiopezidae and probably also Ophiomyxidae and Ophiobyrsidae. Almost all vertebrae are zygospondylous; no streptospondylous vertebrae indicate the absence of the order Euryalida here. Most of the ophiuroids belong to the orders Amphilepidida and Ophiacanthida. Ophiotitanos serrata, Ophiomyxa? aff. jekerica, Ophiojagtus? sp. and some other taxa resembling ophiuroid assemblages from the Late Cretaceous of central, western and northern Europe. With respect to the late Cenomanian age, the depth of the sea and the taxonomic composition, there are some similarities with ophiuroids of the Bohemian Cretaceous Basin. The mid-ramp subtidal facies suggests that brittle stars lived here in a warm, euphotic and probably shallow sea.     

Cenomanian cheilostome bryozoans from Devon,England

The Cenomanian witnessed a spectacular evolutionary radiation of cheilostome bryozoans, both in terms of species diversity and morphological disparity. However, Cenomanian cheilostome faunas are inadequately known. Twelve species of cheilostome bryozoans are here described from the Cenomanian Beer Head Limestone Formation of SE Devon, England, a nearshore facies of limestones and sands. Two of the cheilostome species are new – Wilbertopora manubriformis sp. nov. and Foratella cervisia sp. nov. – and five cannot be identified beyond genus level. Syntypes of Foratella forata (d’Orbigny, 1853), the Senonian type species of Foratella Canu, 1900, are illustrated using SEM and a lectotype is chosen. All of the species present are neocheilostomes, which were larval brooders. Compared with the non-brooding malacostegans that dominate pre-Cenomanian faunas, most species have avicularia and extensive frontal walls, features probably adaptive against small predators.     

Le passage Cénomanien–Turonien dans le Nord-Ouest algérien (coupe de Douar Menkouchi,Ouarsenis) : biostratigraphie des radiolaires

The Ouarsenis Massif belongs to the Algerian Tell domain which is considered as the eastern part of the Maghrebian Tethys former margin. The Cenomanian-Turonian Douar Menkouchi section outcropping in the eastern side of the Ouarsenis massif is composed of marls and laminated limestone alternations, including massive limestone and a biosiliceous bed toward the upper part of the succession. It reveals the presence of well-preserved and diversified radiolarians. In this study, we have identified for the first time in the Algerian domain, age-diagnostic radiolarian assemblages characterizing the Cenomanian-Turonian transition (C/T). The organic-rich laminated beds (black shales) confined to Silvae Zone, Cenomanian in age and underlying a biosiliceous interval, have provided radiolarian assemblages dominated by Pseudodictyomitrae. The successions overlying the biosiliceous interval have provided diversified radiolarian assemblages including Hagiastridae (i,e. Crucella cachensis, Alievium cf. superbum) and abundant Dictymitrae taxa (i,e. Dictyomitra cf. napaensis and Dictyomitra undata) indicating early Turonian age. These marl-limestone alternations are assigned to the Alievium superbum Zone. Considering taphonomic and diagenetic implications on assemblages content, we conclude that organic-rich beds and biosiliceous interval outline the latest Cenomanian. The radiolarian assemblage composition exhibits similarities to microfauna recovered from Bonarelli Horizon in Central Italy. Morphological similarities are also deduced from assemblages containing Pseudodictyomitrae tiara morphotypes (synonym of P. nakasekoi) which resemble those recovered from ophiolitic intervals in Cyprus and Oman areas.     

Campanian-Maastricthian (Late Cretaceous) veneroids (Bivalvia: Heterodonta) from the Ariyalur Group,South India

Eleven veneroid (Bivalvia) species are systematically described from the Campanian-Maastrichtian (Late Cretaceous) sediments of Ariyalur sub-basin of South India. Among these, only Crassatella (Crassatella) macrodonta (Sowerby) and Arctica lacianata (Stoliczka) were earlier recorded by Stoliczka. Protocardia (Pachycardium) madagascariensis (Colignon), Protocardia (Pachycardium) pauli (Cocquand), Epicyprina angulata (Sowerby), Venilicardia truncata (Sowerby), and Calva (Egelicalva) buttensis (Anderson) were previously unknown from the Late Cretaceous horizons of the Indian sub-continent. The present record also includes a new species Palaeomoera stoliczkai n. sp. erected on the basis of its unique hinge characters and surface features. Lucina (Lucina) cf. fallax Forbes, Nicaniella (Nicaniella) aff. trigonoides (Stoliczka), and Corbicula? sp. indet., are tentatively identified because of their imperfect preservation. The present record may add useful information to the understanding of the Late Cretaceous palaeobiology of the region.     

Taxonomical and biostratigraphical significance of the North African radiolitid rudist bivalve Praeradiolites biskraensis (Coquand, 1880)

Abstract: The revision of the radiolitid rudist bivalve Praeradiolites biskraensis (Coquand), including shell morphology and structure, taxonomical status, and palaeogeographical and stratigraphical distribution, was undertaken. We studied Coquand’s collection, other specimens from the type locality, Col de Sfa, and other Algerian fossil localities, as well as recently collected material from the Gafsa region in Tunisia. A neotype from Col de Sfa is proposed. The stratigraphical distribution of the species is bracketed in the Upper Cenomanian, using the distribution of co‐occurring ammonites in Tunisia and microfossils in Algeria. The palaeogeographical distribution is verified for Algeria and Tunisia based on all records in North Africa. Survey of the taxonomical status and problems of related radiolitid genera has resulted in revised diagnoses of Praeradiolites Douvillé, Eoradiolites Douvillé, Sphaerulites Lamarck and Radiolites Lamarck and revealed problems with Radiolites fleuriaui d’Orbigny, which is being the type species of Praeradiolites. Maghrebites gen. nov. is proposed for the North African radiolitid rudist Praeradiolites biskraensis (Coquand).     

Découverte d’une nouvelle faune d’âge cénomanien dans la région de Forthassa (Atlas saharien occidental,Algérie) : Implications biostratigraphiques et paléoenvironnementales

The upper Cretaceous of the eastern part of the Ksour Mountains (Western Saharan Atlas, Algeria) is classically subdivided into three fossiliferous lithostratigraphic formations: El Rhelida (lower Cenomanian), Mdaouer (lower-middle Cenomanian) and Rhoundjaïa (upper Cenomanian-lower Turonian). The western part of the Ksour Mountains, which is less documented and poorly known, is here the subject of a detailed sedimentological and palaeontological study. Near Hassi Djeifa locality (Forthassa) the upper Cretaceous is represented by the upper part of Mdaouer Formation and by the lowermost part of Rhoundjaïa Formation. The deposits attributed to the Mdaouer Formation are composed of reddish or green marlstone intercalated by biolaminated limestone, bioclastic limestone with gastropods and bivalves, and sandstone. The selachians (Mafdetia tibniensis, Baharipristis bastetiae), pycnodontiform fishes, and ostracod fauna (Damonella spp., Ilyocypris? sp., Cypridea sp., Paracypria? sp.) coming from marly beds are studied in detail. The two selachian species (Order of Rajiformes) were so far restricted to the Early Cenomanian of Egypt. Our sedimentological and palaeontological data support a probable Early Cenomanian age of the studied deposits and indicate a coastal plain palaeoenvironment continually influenced by the action of tide.     

Cenomanian Cephalopods of Bellezma-Aures mountains,NE Algeria: Taxonomy and biostratigraphy

The Cenomanian Smail Marl Formation in the Bellezma and Aures mountains of northeastern Algeria is well exposed and rich in macroinvertebrates, including cephalopods. Twenty-five ammonite species and two nautiloid species from the Thénièt El Manchar, Djebel Metrassi and Djebel Bouarif sections are described and seven assemblage zones proposed as provisional working units: Mantelliceras mantelli–Sharpeiceras laticlavium Assemblage Zone (lower Cenomanian), Mantelliceras dixoni Assemblage Zone (uppermost lower Cenomanian), Cunningtoniceras inerme Assemblage Zone (lower middle Cenomanian), Acanthoceras rhotomagense and Acanthoceras cf. rhotomagense Assemblage Zone (middle middle Cenomanian), Acanthoceras amphibolum Assemblage Zone (upper middle Cenomanian), Acanthoceras jukesbrownei Assemblage Zone (uppermost middle Cenomanian), and Neolobites vibrayeanus Assemblage Zone (lower upper Cenomanian). The lower Cenomanian Mantelliceras mantelli–Sharpeiceras laticlavium Zone is subdivided into the Submantelliceras aumalense, Sharpeiceras schlueteri and Mantelliceras saxbii subzones. The base of the middle Cenomanian is marked by the disappearance of species of Mantelliceras and the appearance of the scleractinian coral Aspidiscus cristatus (Lamarck, 1801), associated with Cunningtoniceras inerme (Pervinquière, 1907). The middle Cenomanian contains abundant A. cristatus and species of Acanthoceras, i.e., A. cf. rhotomagense (Defrance in Brongniart, 1822), A. jukesbrownei (Spath, 1926) and A. amphibolum Morrow, 1935. An ammonite zonal scheme is then applied to the Cenomanian exposed in the Bellezma-Aures mountains located on the southern Tethys margin in Algeria.     

Les échinides du Turonien de la Formation de l’Azilé du bassin côtier gabonais dans la région de Libreville Sud

Study of Turonian echinoids from Gabon store section allowed us to distinguish 10 species belonging to 2 genera: Mecaster pseudofourneli (Péron et Gauthier 1878), Mecaster toucasanus (d’Orbigny, 1854), Mecaster africanus (Coquand, 1862), Mecaster semicavatus (Peron et Gauthier 1880), Mecaster verneuili (Desor, 1847), Mecaster cf. orbignyanus (Desor, 1857), Mecaster palpebratus (Loriol, 1888), Mecaster sp.1, Mecaster sp. 2, Epiaster michelini (Agassiz) 1847. All species are found for the first time in Gabonese coastal basin. The composition and the distribution of echinoids fauna and the sedimentary characteristics indicate a proximal shallow platform deposit environment, with warm water and soft substrate. Two types of depositional environment are suggested: (1) a deep part of the proximal platform, represented by silty limestones and (2) a shallower part of the proximal platform, represented by limestones.     

The heteromorph ammonite genus Ancyloceras (Ancyloceratidae) in the Paris Basin (lower Aptian,Lower Cretaceous,NE France)

In the present work, we examine a sample of 54 specimens of the heteromorph ammonite genus Ancyloceras d’Orbigny, 1842 from the Argiles à Plicatules Formation (lower Aptian, Lower Cretaceous) of the eastern Paris Basin (NE France). The results are as follows: (1) the sample is regarded as monospecific and assigned to the well-named species Ancyloceras varians d’Orbigny, 1842; (2) its variability is continuous and concerns as well as adult size, coiling and shell ornamentation. Adult size varies by a factor of two from one individual to another. The angle between the proversum and the retroversum is variable. The ornamentation on the spiral and the proversum varies between robust morphotype with trituberculate strong ribs separated by few smooth intercalaries ribs and slender morphotype with feebly tuberculate ribs. There are no arguments in favor of sexual dimorphism in Ancyloceras varians.     

The Cenomanian–Turonian boundary in Jordan: Ammonite biostratigraphy and faunal turnover

Well-exposed fossiliferous Upper Cenomanian–Lower Turonian marine sedimentary rocks are present in west-central Jordan. Ammonites serve as an important faunal marker for this interval and can be used to subdivide the Cenomanian–Turonian transition into two upper Cenomanian biozones (Neolobites vibrayeanus and Vascoceras cauvini) and two lower Turonian biozones (Vascoceras proprium and Choffaticeras segne). A revised stratigraphic range of the Vascoceras cauvini Zone in the study area is proposed, consisting of the Metoicoceras geslinianum and Neocardioceras juddii zones of the standard zonation. Based on intercontinental biostratigraphic correlation, a minor unconformity appears to be present around the Cenomanian–Turonian boundary, and a part of the lower Turonian is probably missing. In addition, a faunal turnover is recorded in the uppermost Cenomanian, marked by the disappearance of most of the Cenomanian taxa, including Costagyra olisiponensis (Sharpe), Ceratostreon flabellatum (Goldfuss), Ilymatogyra africana (Lamarck), Rhynchostreon suborbiculatum (Lamarck), Harpagodes nodosus (Sowerby), and Heterodiadema libycum (Desor). This bioevent is thought to be an effect of the Oceanic Anoxic Event OAE 2; the dramatic shifts in species richness and diversity spanning the Cenomanian–Turonian boundary in the study area occurred in response to the major paleoclimatic and paleoenvironmental perturbations prevailing at that time. The stratigraphic and paleontological patterns studied in Jordan are very similar to those recorded in Egypt in terms of litho- and biostratigraphy, event stratigraphy, and macroinvertebrate content, suggesting the presence of uniform triggering mechanisms and bio-sedimentary responses in the Upper Cretaceous basins of the Middle East and providing clues for a high-resolution correlation between the two areas.     

Cenomanian (Upper Cretaceous) bivalves from the Hameimat Massifs,north of Tebessa,Algeria: Systematics,biostratigraphy, palaeoecological and taphonomical remarks

In the eastern Saharan Atlas, particularly in the northern area of Tebessa Province (NE Algeria), the widely outcropping Cenomanian strata display a highly diversified macrofauna, among which bivalves are prominently represented. Twenty-eight bivalve species are here reported for the first time from the Cenomanian of Hameimat Massifs. Based on the stratigraphic distribution of these bivalves, five bivalve zones were recognized, i.e., Costagyra olisiponensis - Gyrostrea delettrei, Rhynchostreon suborbiculatum - Exogyra conica, Ceratostreon flabellatum, Ilymatogyra africana, and Pycnodonte vesicularis vesiculosa - Rastellum carinatum zones. Correlation to the ammonite biozones of the same region as follows: the Costagyra olisiponensis - Gyrostrea delettrei and the Rhynchostreon suborbiculatum - Exogyra conica zones occur respectively in the Sharpeiceras schlueteri and Mantelliceras saxbii subzones of the lower Cenomanian Mantelliceras mantelli Zone. The Ceratostreon flabellatum Zone is correlated with the middle Cenomanian Acanthoceras rhotomagense Zone. The Ilymatogyra africana Zone is correlated with the upper Cenomanian Calycoceras naviculare and the Metoicoceras geslinianum zones. Finally, the Pycnodonte vesicularis vesiculosa - Rastellum carinatum Zone represents the uppermost Cenomanian. Detailed analysis of biometrical and morphological features of these bivalve specimens provides the most reliable tool within the scope of palaeo-environmental reconstitution and the many palaeo-ecological variables that had driven the development and distribution of these macro-invertebrates. Comparison of these new data to those of adjacent south Tethyian areas supports the homogeneity of the Cenomanian bivalve faunas. Such an affinity underlines more vividly the favorable marine communications and currents driving the geographic dispersal of these bivalves during the Cenomanian.     

Crinoids from the Ouarsenis Massif (Algeria) fill the Lower Cretaceous (Berriasian and Valanginian) gap of northern Africa

The Ouarsenis Massif belongs to the Algerian Tell domain, which is considered as the eastern part of the Maghrebian Tethys former margin. The Berriasian-Valanginian Oued Fodda Formation outcropping in the Kef Aïn El Hadjela section, at the foot of the great peak of the Ouarsenis Massif, is composed of marls and laminated and bioturbated limestone alternations. The marl facies reveals diverse microfauna, including crinoids. These latter are represented by: Isocrinida [isocrinids Balanocrinus cf. gillieroni (de Loriol), Percevalicrinus aldingeri Klikushin, Isocrinus? lissajouxi (de Loriol)], Cyrtocrinida [cyrtocrinids (Phyllocrinus sp., Hemibrachiocrinus sp.)], and Roveacrinida gen. indet. sp. indet. [roveacrinids]. All these, with exception of roveacrinids and phyllocrinids, are noted for the first time from Algeria and African continent (southern margin of Tethys in the Maghreb). Knowledge on Cretaceous crinoids formerly described from Algeria is presented. It is also shown that crinoid assemblage and associated invertebrates are typical for relatively shallow, distal depositional setting situated below storm wave base.     

Middle Jurassic (upper Bajocian) marine vetigastropods from the Western Saharan Atlas,Algeria

Whereas Middle Jurassic gastropods are very well known in Europe and other regions of the world, these faunas have been much less studied from northern Africa and most contributions available in literature have been based on relatively well-preserved material. Except a little lower Bajocian fauna from the Central High Atlas (Morocco) described at the turn of the 21th century, nothing is known about the Middle Jurassic gastropods of the southwestern Tethyan margin. The present paper aims to update the systematics of two vetigastropod species: Obornella cf. granulata (Sowerby, 1818) and Ambercyclus ornatus (Sowerby, 1819) recently found in the upper Bajocian succession of the Ksour Mountains (Tniet el Klakh Formation) at western Saharan Atlas (northern Algeria). The new Ambercyclus material found in well-preserved conditions confirms the absence of umbilicus in Ambercyclus; thus, we emend the original generic diagnosis. The specimens of Obornella cf. granulata and Ambercyclus ornatus represent the first occurrence of both genera and species in the upper Bajocian marine deposits of the western Saharan Atlas, and provide new taxonomic and palaeobiogeographic information about Middle Jurassic vetigastropods in Algeria.     

Cryptic diversity,pathogenicity, and evolutionary species boundaries in Cercospora populations associated with Cercospora leaf spot of Beta vulgaris

The taxonomy and evolutionary species boundaries in a global collection of Cercospora isolates from Beta vulgaris was investigated based on sequences of six loci. Species boundaries were assessed using concatenated multi-locus phylogenies, Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Processes (PTP), and Bayes factor delimitation (BFD) framework. Cercospora beticola was confirmed as the primary cause of Cercospora leaf spot (CLS) on B. vulgaris. Cercospora apii, C. cf. flagellaris, Cercospora sp. G, and C. zebrina were also identified in association with CLS on B. vulgaris. Cercospora apii and C. cf. flagellaris were pathogenic to table beet but Cercospora sp. G and C. zebrina did not cause disease. Genealogical concordance phylogenetic species recognition, GMYC and PTP methods failed to differentiate C. apii and C. beticola as separate species. On the other hand, multi-species coalescent analysis based on BFD supported separation of C. apii and C. beticola into distinct species; and provided evidence of evolutionary independent lineages within C. beticola. Extensive intra- and intergenic recombination, incomplete lineage sorting and dominance of clonal reproduction complicate evolutionary species recognition in the genus Cercospora. The results warrant morphological and phylogenetic studies to disentangle cryptic speciation within C. beticola.     

Upper Aptian–albian Rudist Bivalves from Northern Sinai, Egypt

Rudist bivalves are described from two Upper Aptian–Albian sections in northern Sinai, Egypt. Independent stratigraphical evidence is provided by orbitolinid foraminifera and sequence stratigraphic correlation with other, ammonite–bearing sections of the region. With the exception of Eoradiolites liratus (Conrad) and Sellaea, this is the first record of Lower Cretaceous rudists from Egypt. A rather continuous occurrence of rudists is recorded in the more open marine deposit at Rizan Aneiza, but they occur only in the Middle–Upper Albian at Gebel Raghawi to the south–west. In the uppermost Aptian to basal Middle Albian at Rizan Aneiza, the succession of Eoradiolites plicatus–E. murgensis–E. liratus is interpreted as a lineage of chronospecies. Of particular interest is the presence of canaliculate rudists in the Upper Albian of both sections, as there exists a large gap, spanning the Upper Aptian and most parts of the Albian, in the fossil record of the Caprininae d’Orbigny. Neocaprina raghawiensis sp. nov. and Neocaprina? sp. are recognized as ancestors of Cenomanian species of Neocaprina Pleni?ar and Caprinula d’Orbigny. The inclusion of these genera in the Caprininae d’Orbigny is questioned and the phylogenetic descent from an unidentified Albian taxon with well–developed myophoral cavities is suggested.     

Ammonites diartianus d'Orbigny, 1850,Vascoceratidae du cénomanien supérieur de saint-calais (Sarthe)

Ammonites diartianus d'Orbigny is a Vascocerasoof late Cenomanian (Sciponoceras gracile Zone) age, occuring in both Sarthe (France) and southern England. It is the earliest vascoceratid known from France, and its recognition is of great significance, lending support to recent suggestions that the classic Vascoceras gamai - mundaeChoffat group are of Upper Cenomanian age.     

Revision of the lower Aptian (Lower Cretaceous) ammonite species Cheloniceras cornuelianum (d’Orbigny, 1841)

The aim of the present work is to determine the morphological characteristics of the lower Aptian (lower Cretaceous) ammonite species Cheloniceras cornuelianum (d’Orbigny, 1841) (Douvilleiceratinae, Douvilleiceratidae) on the basis of 32 specimens from the Paris Basin (France), including the lectotype of the species and 23 topotype specimens. It is generally admitted that this species occurs in the Deshayesites forbesi-Dufrenoyia furcata zones interval (lower Aptian). Our study has lead to several unexpected results. First, the study sample of C. cornuelianum is very probably younger and has more primitive traits than expected: it is probably dated around the limit between the Deshayesites forbesi and Deshayesites deshayesi zones and is morphologically close to the earlier genus Procheloniceras Spath, 1923. Secondly, the lectotype is an extreme specimen with much derived traits compared to its original population. It constitutes an example of type-specimen not morphologically representative of its original population, responsible of a risk of misinterpretation of the species. Finally, the intraspecific variability and the proportion of asymmetric specimens of the study sample of C. cornuelianum are very important but there is no evidence of sexual dimorphism.