Lower Cenomanian Research Articles

Crassatella baudeti (Coquand, 1862) du Cénomanien de Batna (NE algérien) : paléobiogéographie, paléoécologie et biostratigraphie

The lower Cenomanian strata from the Batna region (NE Algeria) constitute the richest and most diversified deposits in terms of macro-invertebrates, mainly dominated by bivalves both in terms of specimens and taxa. Among them, Crassatellidae are restricted to the lower Cenomanian stratigraphical levels. They are represented by the single species Crassatella baudeti. The species is easily distinguished by its flattened boat anchor shape and quite strong commarginal lamellae, and is very abundant. It is present in levels ranging from Sharpeiceras schlueteri Subzone to Cunningtoniceras inerme Zone. The species is, therefore, a good marker of the last levels of the lower Cenomanian and the beginning of the midlle Cenomanian. A precise palaeontological description and an environmental discussion were conducted. Thus, Cr. baudeti would be indicative of a shallow environment, with cold but calm waters, normal salinity and moderately soft substrate. Recorded exclusively from the Cenomanian of a few Tethys localities, the exclusive presence of Cr. baudeti reflects a specific thermal gradient and climatic zonation.

Lower Cenomanian (Upper Cretaceous) marine fish fauna from Peștera (Dobrogea, Romania)

Lower Cenomanian (Upper Cretaceous) marine fish fauna from Peștera (Dobrogea, Romania)

SETTINGSLITHOSTRATIGRAPHIC FEATURES OF THE MESO-CAINOZOIC SECTION OF THE JOINT ZONE OF THE NORTHEASTERN SLOPE OF THE UKRAINIAN SHIELD AND THE DNIPRO-DONETS DEPRESSION

The article presents the results of lithostratigraphic studies, that are important for improving of the Meso-Cenozoic stratigraphic scheme of the northeastern slope of the Ukrainian Shield and the zone of its articulation with the southwestern slope of the Dnipro-Donets Depression. The cores of five boreholes drilled in the area of the M‑36-ХІІ (Oster) sheet were studied. The following formations were described: the upper (Korenevo) subsuite of the Dronovka suite of the Induan of the Lower Triassic, the Podluzhna and Nezhyn suites of the Bathonian and the Ichnia suite of the lower Callovian of the Middle Jurassic, the Ivanytsa suite of the middle Callovian — Oxfordian of the Jurassic, the Buromka formation of the lower Cenomanian and strata of chalk-like marls of the middle Cenomanian — Turonian of the Upper Cretaceous, the Upper Paleocene Merla suite, the Lower Eocene Kaniv suite, the Middle Eocene Buchak and Kyiv suites, the Upper Eocene sandy-clay strata and the Lower Oligocene Mezhyhirya suite. The boundaries of the local strata are characterized. The lithostratigraphic characteristics of the Meso-Cenozoic section of the northeastern slope of the Ukrainian Shield and the zone of its articulation with the southwestern slope of the Dnipro-Donets Depression are described. Differences in the lithological characteristics of the listed local units of the slope of the Shield and the adjacent side of the depression have been noted. Relatively shallow facies of the periphery of sedimentary basins within the northeastern slope of the Ukrainian Shield are separated into auxiliary lithostratigraphic local units — bed and member. There are a member of gray-colored sandy rocks of the lower subsuite of Dronovka suite of Lower Triassic, bed of clayey sand-silt rocks of the periphery of the of the Podluzhna suite the lower Bathonian of the Middle Jurassic, bed of chocolate-brown sandy-clay sediments of the periphery of the Ichnia suite of the lower Callovian, bed of siliceous-silt-clay-sandy sediments of the the Ivanytsa suite of the middle Callovian — Lower Oxfordian Jurassic, bed of chocolate-brown sandy-clay sediments of the periphery of the Upper Eocene Obukhiv suite. The lack of low-thickness intercalations of siltstones and limestones is characteristic of the Nezhyn suite of the Bathonian on the northeastern slope of the Ukrainian Shield. The sustained lithological features are characteristic of the Upper Cretaceous Buromka suite, the Paleogene Merla, Kaniv, Buchak and Kyiv suites. The difficulties in dividing the middle Cenomanian — Turonian section of the Upper Cretaceous into the units of approved stratigraphic schemes are shown. Keywords: lithostratigraphy, Triassic, Jura, Cretaceous, Paleogene, formation, bed, member, Northern Ukraine.

Crocodyliform remains from the Upper Cretaceous of Central Asia – evidence for one of the oldest Crocodylia?

The Late Cretaceous is a key time interval for the understanding of origins and diversification of the crown-group Crocodylia and its extant lineages – Alligatoroidea, Crocodyloidea, and Gavialoidea. Yet, the fossil record of crocodylians in the beginning of the Late Cretaceous is scarce, obscuring the early evolutionary history of the clade. Here I review all known material of long-snouted crocodyliforms from the Upper Cretaceous (Cenomanian–Santonian) of Central Asia. Based on the extensive sampling in the Dzharakuduk locality (Bissekty Formation) and the distinctive anatomy of individual elements, they are referred to the enigmatic taxon Zholsuchus procerus Nessov et Cherepanov, 1989. Comparable specimens from other localities are tentatively attributed to Zholsuchus sp. or cf. Zholsuchus sp. Zholsuchus is herein confirmed as a valid taxon for the first time since its establishment. Based on extensive morphological comparison, I hypothesize that it is potentially a crown-group crocodylian that may be related to Gavialoidea. However, additional material is required to test taxonomic and phylogenetic hypotheses proposed in this study. Zholsuchus is allegedly a medium-sized crocodylian, attaining minimal total body lengths of 2 m and perhaps ranging up to 2.5–3 m. Remains associated with this taxon are rare but consistently recovered in the lower Cenomanian–Santonian deposits of Uzbekistan and Kazakhstan. Zholsuchus, along with Portugalosuchus from Cenomanian of Portugal, may be the oldest presently known crocodylians, which expands the fossil record of the crown-group back into the beginning of the Late Cretaceous and suggests the much earlier origins of the clade than it has been usually acknowledged.

New Ankylosaurian Cranial Remains From the Lower Cretaceous (Upper Albian) Toolebuc Formation of Queensland, Australia

Australian dinosaur research has undergone a renaissance in the last 10 years, with growing knowledge of mid-Cretaceous assemblages revealing an endemic high-paleolatitude Gondwanan fauna. One of its most conspicuous members is ankylosaurs, which are rare but nonetheless occur in most Australian dinosaur-bearing formations spanning the uppermost Barremian to lower Cenomanian. Here we describe a partial ankylosaur skull from the marine Toolebuc Formation exposed near Boulia in western Queensland, Australia. This skull represents the oldest ankylosaurian material from Queensland, predating the holotype of Kunbarrasaurus ieversi, which was found in the overlying Allaru Mudstone. The ankylosaur skull is encased in a limestone concretion with the maxillary tooth rows preserved only as impressions. Synchrotron radiation X-ray tomography was used to non-destructively image and reconstruct the specimen in 3D and facilitate virtual preparation of the separate cranial bones. The reconstruction of the skull revealed the vomer, palatines, sections of the ectopterygoids and maxillae, and multiple teeth. The palate has posteriorly positioned choanae that differs from the more anterior placement seen in most other ankylosaurians, but which is shared with K. ieversi, Akainacephalus johnsoni, Cedarpelta bilbeyhallorum, Gobisaurus domoculus, and Panoplosaurus mirus. Phylogenetic analyses place the new cranial material within the recently named basal ankylosaurian clade Parankylosauria together with K. ieversi. This result, together with the anatomical similarities to the holotype of K. ieversi, permits its referral to cf. Kunbarrasaurus sp. This specimen elucidates the palatal anatomy of Australian ankylosaurs and highlights one of the most ubiquitous components of Australian mid-Cretaceous dinosaur faunas.

Dinoflagellate cyst biostratigraphy of initial Neotethys transgression deposits from the Cenomanian and Turonian in the Tarim Basin, western China

Under the great transgressions of the Late Cretaceous, the Neotethys Sea firstly invaded the western Tarim Basin, center Asian and this continued until the Paleogene. This study presents successive dinoflagellate cyst (dinocyst) records from the Kukebai Formaion deposited during initial transgressive periods. A total of 45 samples from the Core ZK 5-2 drilled in the southern part of the western Tarim Basin yield 78 taxa including 74 taxa of dinocysts, two genera of chlorophyte algae, and two acritarch species. Upwardly, three dinoflagellate zones are distinguished in the Kukebai Formation: Subtilisphaera perlucida (interval Zone), Cyclonephelium brevispinatum (interval zone), and Heterosphaeridium difficile (interval zone) respectively. Successive dinocyst records in this study calibrate the chronostratigraphy of the Kukebai Formation from the lower Cenomanian to the lowermost Turonian. A high abundance of Subtilisphaera perlucida and sporadic Litosphaeridium siphoniphorum can be observed in the lowest Kukebai Formation, probably indicating initial sea transgression in the Tarim Basin that took place in early Cenomanian. The distribution events of key dinocyst taxa such as the first occurrence of the H. difficile and the last occurrence of consistent occurrence of Litosphaeridium siphoniphorum, indicate that the C/T boundary interval should be approximately 183 m deep in Core ZK 5–2, at the uppermost Middle Kukebai Formation.

Syndepositional glauconite as a paleoenvironmental proxy - the lower Cenomanian Chalk of Cap Blanc Nez (N-France)

At Cap Blanc Nez (Channel coast, France), the chalk of the Lower Cenomanian is very rich in glauconite. Glauconite is of authigenic origin and requires the mobilization of chemical elements for its growth: Si, Fe and K. If we already know thanks to elementary geochemistry (Ge/Si ratio) that the silica of the flint present in the chalk originates from the dissolution of sponges, is it the same for glauconite? This question only makes sense if glauconite is proved to be autochthonous and synsedimentary, and not reworked during the Cenomanian transgression. In addition, we wanted to know whether the study of the content of trace elements in glauconite could provide information on the conditions of authigenesis in glauconious chalk.The clay content of the chalk from the Lower Cenomanian has been examined and the green minerals were extracted from the rock to study their morphology, mineralogy, geochemistry (major & trace elements) and grain size. The chalk consists of calcium carbonate, smectite and true glauconite, in the form of pellets, sometimes with rare traces of quartz and some centimeter-scale phosphate gravel. The grain-size distribution of the glauconites varies from one sample to another and is always poorly sorted, which militates in favor of an autochthonous (not reworked) origin of these minerals. This origin is also suggested by the virtual absence of terrigenous minerals, except for smectite known for its potential for wide distribution in the marine environment. The geochemistry of the samples shows a very homogeneous composition of major and trace elements, with a K2O content greater than 8%. This characterizes these glauconites as being very evolved, which indicates a long authigenic formation time (> 100 ky) and therefore an extremely reduced or irregular sedimentation rate. Here, glauconites are very rich in germanium, which makes it impossible to identify a source of silica (unlike what is possible with flints). It cannot therefore be said that the silica results from the dissolution of sponges but this enrichment in Ge, coupled with that in vanadium and the absence of enrichment in molybdenum, indicates a slightly reducing deposition milieu (suboxic). Such conditions usually favor organic matter accumulation, but not here, due to protracted sedimentation hiatuses. Lastly, glauconite trapped relatively large amounts of Ge due to reducing conditions and long exposure time to seawater, which makes it a potential chronometer assessing the duration of authigenesis, and a possible compartment of the marine cycle of germanium.

Lower Cenomanian ammonites from la Bédoule, Bouches-du-Rhône, France

Lower Cenomanian ammonites from la Bédoule, Bouches-du-Rhône, France

Aptian–Cenomanian echinoids from northern Sinai, Egypt

Aptian–lower Cenomanian sedimentary rocks, assigned to the Risan Aneiza and Halal formations and exposed in northern Sinai yield rich, well-preserved echinoid assemblages. Thirty-two species (16 regular and 16 irregular), in 27 genera, have been identified and are here systematically described from the Gebel El Tourkumanyia and Wadi El Karm sections (El Maghara area). A new genus, Sinaiosalenia, and two new species, Sinaiosalenia rhombohedralis (lower Cenomanian) and Globator aegyptiaca (middle Albian), both from Gebel El Tourkumanyia, are erected. Additionally, two species are recorded from Egypt for the first time: Emiratia raskhaimahensis Ali, 1990 and Pseudananchys ludovici (Fourtau, 1912).

Radiolaria from the lower Cenomanian (Upper Cretaceous) of Crimea. Part 2. Nassellaria

Well-preserved Late Cretaceous (early Cenomanian) radiolarians were recovered from two sections in Crimea: Bodrak River and Sel’-Bukhra Mountain. Abundant and diverse Nassellaria were studied and four new species are described: Holocryptocanium pseudoastiense nov. sp., Diacanthocapsa bodrakiense nov. sp., Novixitus riedeli nov. sp. and Rhopalosyringium panovi nov. sp. Herein Archaeodictyomitra (?) speciosa Bragina is newly attributed to the genus Obeliscoites O’Dogherty and Dorypyle ovoidea (Squinabol) is tentatively attributed to the genus Homeoarchicorys Empson-Morin. The stratigraphic ranges of Diacanthocapsa urkutica Bragina, Distylocapsa squama O’Dogherty, Novixitus subtilis Bragina, and Siphocampe altamontensis (Campbell and Clark) are more precisely defined with their lower limits expanded to the lower Cenomanian and the upper limits of Pseudodictyomitra languida O’Dogherty and Thanarla conica (Squinabol) extended to the lower Cenomanian.

A detailed osteological description of Xenotarsosaurus bonapartei (Theropoda: Abelisauridae): implications for abelisauroid phylogeny

Xenotarsosaurus bonapartei was the third abelisaurid theropod dinosaur to be named from Argentina. The holotype comprises two partial anterior dorsal vertebrae and a nearly complete right hind limb from the Upper Cretaceous (lower Cenomanian–upper Turonian) Bajo Barreal Formation, central Patagonia, Argentina. The materials display morphological features that undoubtedly position Xenotarsosaurus within Abelisauroidea. Moreover, detailed comparisons with members of that theropod group confirm the close relationship of this taxon to abelisaurids. Here we provide an emended diagnosis of Xenotarsosaurus bonapartei that includes five newly recognized autapomorphies: (1) anterior dorsal vertebrae with large, strongly dorsoventrally developed parapophyses; (2) anterior dorsal vertebrae with well-developed centroprezygapophyseal fossae that are taller dorsoventrally than wide mediolaterally; (3) fibular condyle of femur triangular in shape and projecting posteriorly; (4) well-marked groove on anterolateral corner of proximal fibula; and (5) iliofibularis tubercle of fibula distally interrupted by hook-like concavity. To determine its systematic position within Abelisauroidea, we incorporated Xenotarsosaurus into a phylogenetic analysis, recovering this theropod as a non-carnotaurine abelisaurid more derived than Eoabelisaurus mefi. Xenotarsosaurus displays several plesiomorphic traits when compared with penecontemporaneous abelisaurids from the Neuquén Group. Similarly, other non-avian dinosaur taxa from the Bajo Barreal Formation are frequently postulated as more phylogenetically basal than coeval forms from northern Patagonia. This scenario suggests the potential existence of provincialism in early Late Cretaceous continental vertebrate faunas of southern South America. The present study increases knowledge of abelisaurid systematics, evolution, and paleobiogeography and augments our understanding of the Upper Cretaceous dinosaur assemblage of central Patagonia.

The microcrinoid taxonomy, biostratigraphy and correlation of the upper Fredericksburg and lower Washita groups (Cretaceous, middle Albian to lower Cenomanian) of northern Texas and southern Oklahoma, USA

The stratigraphy of the upper Fredericksburg and lower Washita groups of northern Texas and southern Oklahoma is described, and biostratigraphical correlation within the region, and further afield, using micro­ crinoids, ammonites, planktonic foraminiferans and inoceramid bivalves is summarised. The taxonomy of the roveacrind microcrinoids is revised by the senior author, and a new genus, Peckicrinus, is described, with the type species Poecilocrinus porcatus (Peck, 1943). New species include Roveacrinus proteus sp. nov., R. morganae sp. nov., Plotocrinus reidi sp. nov., Pl. molineuxae sp. nov., Pl. rashallae sp. nov. and Styracocrinus thomasae sp. nov. New formae of the genus Poecilocrinus Peck, 1943 are Po. dispandus forma floriformis nov. and Po. dispandus forma discus nov. New formae of the genus Euglyphocrinus Gale, 2019 are E. pyramidalis (Peck, 1943) forma pyramidalis nov., E. pyramidalis forma radix nov. and E. pyramidalis forma pentaspinus nov. The genera Plotocrinus Peck, 1943, Poecilocrinus and Roveacrinus Douglas, 1908 form a branching phylogenetic lineage extending from the middle Albian into the lower Cenomanian, showing rapid speciation, upon which a new roveacrinid zonation for the middle and upper Albian (zones AlR1–12) is largely based. Outside Texas and Oklahoma, zone AlR1 is recorded from the lower middle Albian of Aube (southeastern France) and zones AlR11–CeR2 from the Agadir Basin in Morocco and central Tunisia. It is likely that the zonation will be widely applicable to the middle and upper Albian and lower Cenomanian successions of many other regions.

Reprint of “Radiolaria from the lower Cenomanian (Upper Cretaceous) of Crimea. Part 1. Spumellaria”

Well-preserved Late Cretaceous (early Cenomanian) radiolarians were recovered from two sections in Crimea: Bodrak River and Sel’-Bukhra Mountain sections. Abundant and diverse representatives of order Spumellaria were recognized and studied. Four new radiolarian species: Becus naidini nov. sp., B. tauricus nov. sp., Praeconocaryomma? bodrakensis nov. sp., and Savaryella? nikishini nov. sp. were described. Moreover, stratigraphical ranges of species Archaeospongoprunum sphaericum Bragina, Crucella lata (Lipman), Patellula cognata O’Dogherty, P. verteroensis (Pessagno), Spongodiscus quasipersenex Bragina were exactly defined (their lower limits are expanded to the lower Cenomanian). The upper limit of stratigraphic range of "Cenodiscus" alievi Pessagno is expanded to the lower Cenomanian. Our results suggest that two rare taxa "Cenodiscus" alievi Pessagno (California Coast Ranges) and Spongodiscus quasipersenex Bragina (West Sakhalin Mountains) are reported for the first time in the Tethyan regions.

A stagodontid mammal from the mid-Cretaceous of France confirms the Euramerican distribution of early marsupialiforms

The global palaeobiogeography of early marsupialiform mammals is still poorly understood due to a meagre fossil record outside western North America. Here, two isolated teeth of a marsupialiform mammal from the lowermost Upper Cretaceous (lower Cenomanian) of southwestern France are described and referred to Stagodontidae, a dentally specialized group whose unambiguous members are so far known exclusively from the Upper Cretaceous of North America. The occurrence of stagodontids in Europe represents additional evidence of faunal exchanges between the two landmasses during the latest Albian–early Cenomanian interval, around 100 million years ago, and shows that early (mid-Cretaceous) marsupialiforms were more widely distributed than previously thought.

A revision of the non-avian dinosaurs ‘Eucercosaurus tanyspondylus’ and ‘Syngonosaurus macrocercus’ from the Cambridge Greensand, UK

The Cambridge Greensand Member (lower Cenomanian: Upper Cretaceous) has yielded a diverse fauna of terrestrial and marine tetrapods, whose remains are largely reworked from the underlying Gault Formation (upper Albian: Lower Cretaceous). Here, we re-describe two of the non-avian dinosaur taxa named from this unit, ‘Eucercosaurus tanyspondylus’ Seeley, 1879 and ‘Syngonosaurus macrocercus’ Seeley, 1879, both of which have been referred to as either ankylosaurs or ornithopods but whose validity has not been rigorously assessed for over a century. Both taxa are interpreted as the remains of iguanodontian dinosaurs but possess no clear diagnostic features. Nevertheless, although ‘Eucercosaurus’ and ‘Syngonosaurus’ are nomina dubia they do indicate that iguanodontians were common components of the Cambridge Greensand tetrapod fauna and, alongside ‘Trachodon cantabrigiensis’ Lydekker, 1888, represent an important datum for understanding iguanodontian distributions during the mid-Cretaceous.

Paleogeographic, paleoclimatic and sea-level implications of glauconite deposits in Egypt: A review

Glauconite deposits are confined to the Western Desert in Egypt of four different sequences and ages from older to younger include, 1) Lower Cenomanian Bahariya Formation, 2) Lower-Middle Campanian Qusseir Formation, 3) Upper Campanian Duwi Formation, and 4) Lutetian-Bartonian Hamra Formation.Lower Cenomanian, Upper Campanian and Lutetian-Bartonian glauconites occur as pellets, while the Lower-Middle Campanian glauconite occurs as fine-grained particles of non-pelletal texture. Based on K2O contents, the Lower Cenomanian and Upper Campanian glauconites are classified as slightly evolved, while the Lower-Middle Campanian and Lutetian-Bartonian glauconite are categorized as evolved. Positive correlations between K2O and Fe2O3 in the Bahariya Formation, Qusseir Formation and Hamra Formation deposits suggest a layer lattice glauconitization mechanism for these deposits. On the other hand, the lack of correlation between Fe2O3 and K2O declines the layer lattice formational mechanism for the Duwi Formation glauconite. A neo-formation mechanism was suggested for this glauconite. Rare earth elements patterns are the same in the four deposits and resemble the shallow sweater pattern.The four glauconite deposits formed in shallow marine environments and might correspond to major eustatic transgressive and global warming events. Glauconite of the Bahariya Formation corresponds to the Early Cenomanian Tethys major transgression in Egypt and can be correlated to the Albian/Cenomanian global cycle boundary as well as the early Cenomanian “hot greenhouse”. The sequence boundary near the topmost part of the Qusseir Formation matches the global warming of the Middle Campanian Event (MCE). The upper Campanian glauconite of the Duwi Formation occurs as lowstand wedge and may correlate to the late Campanian climatic warm optimum. The stratigraphic position of the Hamra glauconite above the unconformity surface refers to transgressive phase that may match with latest Lutetian major sequence boundary (Lu4) and global warming event of the Middle Eocene Climatic Optimum (MECO).Paleogeographic maps show that the Western Desert of Egypt during Cenomanian and Lower Campanian covered by shallow marine setting, which match with the proposed setting for the glauconites in these ages. However, paleogeographic maps for the Upper Campanian and Middle Eocene were modified to fit with the suggested setting of glauconites of these epochs. The prevalence of shallow marine setting during these four ages interprets the restricted occurrences of glauconites at the Western Desert of Egypt during these epochs.

An unrevealed lineage of platypterygiines (Ichthyosauria) with peculiar forefin structure and semiglobal distribution in the mid-Cretaceous (Albian–Cenomanian)

Recent progress in the study of Cretaceous ichthyosaurians resulted in significant reevaluation of their diversity. However, there are still problematic mid-Cretaceous ichthyosaurian taxa, among which are ‘Ophthalmosaurus’ cantabrigiensis Lydekker, 1888 from the upper Albian – lower Cenomanian of England, Maiaspondylus lindoei Maxwell and Caldwell, 2006a from the Albian of Canada and ‘Platypterygius’ ochevi Arkhangelsky, 2008 from the Albian–Cenomanian of European Russia. The listed taxa have a peculiar morphology of the humerus with three distal facets of subequal sizes. Despite their similarity and nearly contemporaneous occurrence, these taxa were never compared to each other. Here we reevaluate their type materials and reveal the evidence for their close relation. We refer these taxa to the genus Maiaspondylus Maxwell and Caldwell, 2006a, recognizing two species – Maiaspondylus lindoei and Maiaspondylus cantabrigiensis comb. nov., whereas ‘Platypterygius’ ochevi is considered a junior subjective synonym of the later. Our phylogenetic analysis places these taxa within derived platypterygiines, further supporting the existence of a previously unrevealed lineage of modest-sized platypterygiine ichthyosaurians with global distribution in the Northern Hemisphere during the Albian–Cenomanian time interval.

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.

Radiolaria from the lower Cenomanian (Upper Cretaceous) of Crimea. Part 1. Spumellaria

Well-preserved Late Cretaceous (early Cenomanian) radiolarians were recovered from two sections in Crimea: Bodrak River and Sel’-Bukhra Mountain sections. Abundant and diverse representatives of order Spumellaria were recognized and studied. Four new radiolarian species: Becus naidini nov. sp., B. tauricus nov. sp., Praeconocaryomma? bodrakensis nov. sp., and Savaryella? nikishini nov. sp. were described. Moreover, stratigraphical ranges of species Archaeospongoprunum sphaericum Bragina, Crucella lata (Lipman), Patellula cognata O’Dogherty, P. verteroensis (Pessagno), Spongodiscus quasipersenex Bragina were exactly defined (their lower limits are expanded to the lower Cenomanian). The upper limit of stratigraphic range of "Cenodiscus" alievi Pessagno is expanded to the lower Cenomanian. Our results suggest that two rare taxa "Cenodiscus" alievi Pessagno (California Coast Ranges) and Spongodiscus quasipersenex Bragina (West Sakhalin Mountains) are reported for the first time in the Tethyan regions.

Asteroids (Echinodermata) from the Barremian (Lower Cretaceous) of the Agadir Basin, west Morocco

AbstractAbundant new material of articulated asteroids from the Taba Starfish Bed (Lower Cretaceous, Barremian) of the Agadir Basin, western Morocco, allows reappraisal of this important fauna, and the recognition, to date, of five taxa belonging to the Astropectinidae, Odontasteridae, Goniasterididae, Terminasteridae, and Asteriidae.Betelgeusia orientalisBlake and Reboul, 2011 is shown to be a junior synonym ofCoulonia platyspinaHess and Blake, 1995, andDipsacaster africanusBlake and Reboul, 2011 comprises material ofC.platyspinaand a new odontasterid, here described asOdontaster tabaensisn. sp.Alkaidia megaungulan. sp. is described and its ontogeny and affinities discussed. From this, it is concluded that the Terminasteridae, revised to include the generaTerminasterandAlkaidia, is sister taxon to the extant family Zoroasteridae, and both are placed in the suborder Zorocallina of the Forcipulatida. The Taba fauna is a representative of a distinctive Lower Cretaceous asteroid assemblage that existed in northern Tethys from the Barremian to the Cenomanian and is also well known from the Albian and lower Cenomanian of Texas.UUID:http://zoobank.org/b2ecdd06-685d-4242-9e49-985f9d7a3cc1