A gigantic caenagnathid oviraptorosaurian (Dinosauria: Theropoda) from the Upper Cretaceous of the Gobi Desert,Mongolia

A large, isolated symphyseal region of fused dentaries of an oviraptorosaurian was found in the Upper Cretaceous Bayn Shire Formation at Tsagaan Teg in the Mongolian Gobi Desert. A phylogenetic analysis places this specimen within Caenagnathidae. This specimen is comparable in size and morphology to the gigantic caenagnathid Gigantoraptor erlianensis from the Iren Dabasu Formation in China and is likely closely related to it. The occurrence of the specimen with possible affinities to G. erlianensis in the Bayn Shire Formation is consistent with the hypothesized correlation between the Bayn Shire and Iren Dabasu formations based on the co-occurrences of vertebrate fossils, especially turtles.     

中亚与亚洲中部晚白垩世的陆生脊椎动物组合对比

通过对前人建议的26个生物地层标志化石存在与否的简约分析,中亚与亚洲中部晚白垩世的陆生脊椎动物组合的相对层位得到了更清楚的揭示。此区最古老的组合是乌兹别克斯坦克孜勒库姆沙漠的Khodzhakul组合(早塞诺曼期),其次为蒙古戈壁沙漠东部BaynShire组的下部和上部的组合(塞诺曼期至桑顿期)。中国内蒙古二连达布苏动物群与中亚的土伦期—桑顿期动物群属于同一类群,因为它们均具龟鳖类Khunnuchelys,前者时代可能为桑顿期。三个中亚的组合(Bissekty、Yalovach和Bostobe组合)中有两个地方性的鳄形类(Kansajsuchus和Tadzhikosuchus)和一个出现于戈壁沙漠的鳄形类(Shamosuchus)化石。戈壁沙漠的坎潘期至马斯特里赫特期组合与北美同期动物群为同一类群。Djadokhta组与BarunGoyot组的坎潘期脊椎动物组合具有高度的地方性,并反应了半干旱的古环境。产自Nemegt组的组合生存于比较潮湿的环境。在组成上,这一组合与其他河流相沉积环境(Bissekty、二连达布苏以及北美Judithian期和Lancian期的组合)相似。具顶饰的鸭嘴龙Saurolophus的存在,支持了Nemegt组合为马斯特里赫特期时代。戈壁沙漠的这三个组合(Djadokhta、Barun Goyot和Nemegt组合)被归为一类,因为它们共同拥有地方性的龟类Mongolemys和兽脚亚目的小驰龙类。亚洲中部和北美的坎潘期至马斯特里赫特期组合与亚洲更加古老的组合不同在于存有暴龙科、肿头龙亚目和鸭嘴龙科。在中亚,由于地区性的海侵,这一时间段内的陆生脊椎动物组合多不清楚。     

New material of the large-bodied caenagnathid Caenagnathus collinsi from the Dinosaur Park Formation of Alberta,Canada

A reexamination of large caenagnathid material from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Alberta, Canada, reveals undescribed material referable to Caenagnathus collinsi. A femur, two astragalocalcanei, two metatarsals, two unguals, and a caudal vertebra provide anatomical information on Caenagnathus collinsi. Estimates of femoral length based on the proportions of other oviraptorids suggest that the non-femoral material represents a taxon intermediate in size between Chirostenotes pergracilis from the Dinosaur Park Formation and Anzu wyliei from the Maastrichtian Hell Creek Formation. The femur is within the range of predictions, and confirms the body size estimates based on the other material. The large size of the material and a number of morphological characters distinguish the material from Chirostenotes pergracilis and suggest that it is referable to Caenagnathus collinsi. The relative diversity of caenagnathids in the Dinosaur Park Formation is likely underestimated.     

Biostratigraphic and biogeographic implications of a hadrosaurid (Ornithopoda: Dinosauria) from the Upper Cretaceous Almond Formation of Wyoming,USA

The results of Barnum Brown's 1937 expedition to the Almond Formation of Wyoming consisted of two unidentified ceratopsian skulls and a partial hadrosaurid specimen (AMNH 3651). The hadrosaurid is here attributed to the Maastrichtian genus Saurolophus, verifying previous biostratigraphic correlations of this formation using ammonite zones. Fossiliferous lower Maastrichtian formations occurring latitudinally between those of Alberta, Canada, and southwestern Texas, USA, such as the Almond Formation, are essential for testing the effects and duration of apparent hadrosaurid faunal segregation earlier in the Campanian, and indirectly aiding in the placement of faunal boundaries that are currently unknown for the late Campanian. The discovery of Saurolophus in Wyoming, a close relative of the Campanian genus Prosaurolophus, affirms that the segregation of hadrosaurid faunas established in the late Campanian (～75 Ma) continued for at least 3 million years. Combining occurrences of Saurolophus from Mongolia and the Moreno Formation of California with those of Alberta, Canada, this genus appears to have had one of the largest geographic ranges of any equivalent clade of hadrosaurid dinosaur, although species level distributions are still uncertain.     

Petreşti-Arini – An important but ephemeral Upper Cretaceous continental vertebrate site in the southwestern Transylvanian Basin,Romania

The Transylvanian region of Romania preserves some of the most unusual and iconic dinosaurs in the global fossil record, including dwarfed herbivores and aberrant carnivores that lived during the very latest Cretaceous (Maastrichtian) in an ancient island ecosystem (the Haţeg Island). A series of artificial outcrops recently exposed during a hydroelectric project, the Petreşti-Arini section near Sebeş in the Transylvanian Basin, records a 400+ meter sequence documenting the transition from fully marine to terrestrial environments during the Campanian–Maastrichtian. Calcareous nannofossil biostratigraphy indicates that the lower marine beds in this section, part of the uppermost Bozeş Formation, can be assigned to the CC22 biozone, corresponding to the lower–mid upper Campanian. These beds smoothly transition, via a brackish-water unit, into the fully continental Maastrichtian Sebeş Formation. Dinosaur and pterosaur fossils from the uppermost Bozeş Formation can be assigned a late Campanian age making them the oldest well-dated terrestrial fossils from the Haţeg Island, and indicating that the classic Haţeg dinosaur fauna was becoming established by this time, coincident with the first emergence of widespread land areas. Vertebrate fossils occur throughout the overlying Sebeş Formation at the site and are dominated by the small-bodied herbivorous dinosaur Zalmoxes. The dominance of Zalmoxes, and the absence of many taxa commonly seen elsewhere in Maastrichtian sites in Romania, suggests the possibility that either the Petreşti-Arini section preserves a somewhat unusual near-shore environment, or the earliest Haţeg Island dinosaur communities were structured differently from the more diverse communities later in the Maastrichtian. Alternatively, due to the limited sample size available from the studied succession, it is also conceivable that sampling biases give an incomplete portrayal of the Petreşti-Arini local fauna. Support for any one of these alternative hypotheses requires further data from Petreşti-Arini as well as from the larger Transylvania area.     

Latest Campanian and Maastrichtian Siderolitidae (larger benthic foraminifera) from the Pyrenees (S France and NE Spain)

The siderolitids from the uppermost Campanian and Maastrichtian deposits of the Pyrenees have been re-studied. This has revealed a high diversity and rapid replacement of taxa, confirming the group as a good tool for high resolution biostratigraphy. Two genera have been found in the uppermost Campanian–Maastrichtian interval in the Pyrenean deposits: Siderolites Lamarck, and Wannierina Robles-Salcedo. Siderolites, with canaliferous spines or denticulate periphery, is represented by four species replacing each other from the latest Campanian to Maastrichtian: Siderolites praecalcitrapoides (latest Campanian), S. pyrenaicus sp. nov. (early Maastrichtian), Siderolites calcitrapoides (late Maastrichtian) and Siderolites denticulatus (late Maastrichtian). Wannierina is characterised by well-developed keels and ramified marginal canals. Two species of Wannierina have been identified and they succeeded one another from latest Campanian to early Maastrichtian: Wannierina vilavellensis sp. nov. (latest Campanian) and Wannierina cataluniensis (early Maastrichtian). The species of the genus Siderolites inhabited shallow waters of tropical to subtropical platforms with moderate-to-high water-energy conditions and those of the genus Wannierina are typical of deep–water low-energy environments but still in the eutrophic zone.     

Palynostratigraphy and palaeoenvironmental significance of the Cretaceous palynomorphs in the Qattara Rim-1X well,North Western Desert,Egypt

Palynological and palynofacies analyses were carried out on some Cretaceous samples from the Qattara Rim-1X borehole, north Western Desert, Egypt. The recorded palynoflora enabled the recognition of two informal miospore biozones arranged from oldest to youngest as Elaterosporites klaszii-Afropollis jardinus Assemblage Zone (mid Albian) and Elaterocolpites castelainii–Afropollis kahramanensis Assemblage Zone (late Albian–mid Cenomanian). A poorly fossiliferous but however, datable interval (late Cenomanian–Turonian to ?Campanian–Maastrichtian) representing the uppermost part of the studied section was also recorded. The palynofacies and visual thermal maturation analyses indicate a mature terrestrially derived organic matter (kerogen III) dominates the sediments of the Kharita and Bahariya formations and thus these two formations comprise potential mature gas source rocks. The sediments of the Abu Roash Formation are mostly dominated by mature amorphous organic matter (kerogen II) and the formation is regarded as a potential mature oil source rock in the well. The palynomorphs and palynofacies analyses suggest deposition of the clastics of the Kharita and Bahariya formations (middle Albian and upper Albian–middle Cenomanian) in a marginal marine setting under dysoxic–anoxic conditions. By contrast, the mixed clastic-carbonate sediments of the Abu Roash Formation (upper Cenomanian–Turonian) and the carbonates of the Khoman Formation (?Campanian–Maastrichtian) were mainly deposited in an inner shallow marine setting under prevailing suboxic–anoxic conditions as a result of the late Cenomanian and the Campanian marine transgressions. This environmental change from marginal to open (inner shelf) basins reflects the vertical change in the type of the organic matter and its corresponding hydrocarbon-prone types. A regional warm and semi-arid climate but with a local humid condition developed near/at the site of the well is thought to have prevailed.     

A neoselachian shark fauna from the Late Cretaceous of Senegal

A selachian fauna is described for the first time from the Late Cretaceous (Campanian–Maastrichtian) of Senegal. So far, the Campanian Paki Formation has only yielded a single tooth of Rhombodus sp. whereas the Cap de Naze Formation has yielded a more diverse fauna including juvenile Cretalamna cf. Cretalamna biauriculata, Serratolamna serrata, Carcharias cf. Carcharias heathi, ?Carcharias sp., Squalicorax pristodontus, Schizorhiza stromeri, Parapaleobates sp., Rhombodus binkhorsti and Rhombodus andriesi. Teeth of juvenile Cretalamna largely dominate the assemblage. Such an assemblage confirms a Late Maastrichtian age for the unit 3 in the Cap de Naze Formation. The assemblage, although composed of cosmopolitan taxa, is similar to the contemporaneous selachian assemblage from the phosphates of Morocco.     

A protoceratopsid skeleton with an associated track from the Upper Cretaceous of Mongolia

The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert.     

New Spanish Late Cretaceous eusuchian reveals the synchronic and sympatric presence of two allodaposuchids

The recently described clade Allodaposuchidae includes European eusuchian crocodyliforms restricted to the Late Cretaceous (Campanian and Maastrichtian). A new allodaposuchid crocodyliform is here described based on two specimens from the upper Campanian–lower Maastrichtian fossil site of Lo Hueco (Cuenca, Spain). This new taxon, Agaresuchus fontisensis gen. et sp. nov., is described by two complete skulls and a lower jaw associated with one of them. This new species can be distinguished unambiguously from Lohuecosuchus megadontos, the other allodaposuchid known from the same fossil site. The presence of two allodaposuchid crocodyliforms in Lo Hueco allows the recognition of the synchronic and sympatric existence of two representatives of this clade for the first time. The new genus Agaresuchus, comprises a previously described Iberian allodaposuchid species, “Allodaposuchus” subjuniperus, as Agaresuchus subjuniperus, new combination.     

Pararhabdodon isonensis and Tsintaosaurus spinorhinus: a new clade of lambeosaurine hadrosaurids from Eurasia

We present new anatomical information showing that Koutalisaurus kohlerorum, from the Maastrichtian of Lleida Province, northeastern Spain, is most probably the junior synonym of Pararhabdodon isonensis from the same region. Dentary and maxillary characters previously considered as autapomorphies of K. kohlerorum and P. isonensis, respectively, are shown to be synapomorphies uniting the latter with Tsintaosaurus spinorhinus from the Campanian of the Wangshi Group, Shandong Province, China.This study provided conclusive evidence of the presence of the Lambeosaurinae in Europe. Tsintaosaurus spinorhinus and Pararhabdodon isonensis were inferred to form a clade of basal lambeosaurines characterized by a maxilla with an elevated articular facet for the jugal (continuous with the ectopterygoid ridge) and an extremely medially projected symphyseal region of the dentary. This clade originated in Asia during the middle or late Campanian. Pararhabdodon isonensis or its ancestors migrated from Asia to the Iberian island of the European archipelago. Reconstruction of ancestral areas by Fitch parsimony attributes the European occurrence of P. isonensis to a single dispersal event from Asia no later than middle to late Campanian.     

Dinosaur eggshells from the Santonian Milk River Formation of Alberta,Canada

The North American fossil record of dinosaur eggshells for the Cretaceous is primarily restricted to formations of the middle (Albian–Cenomanian) and uppermost (Campanian–Maastrichtian) stages, with a large gap in the record for intermediate stages. Here we describe a dinosaur eggshell assemblage from a formation that represents an intermediate and poorly fossiliferous stage of the Upper Cretaceous, the Santonian Milk River Formation of southern Alberta, Canada. The Milk River eggshell assemblage contains five eggshell taxa: Continuoolithus, Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus. These ootaxa are most similar to those reported from younger Campanian–Maastrichtian formations of the northern Western Interior than they are to ootaxa reported from older middle Cretaceous formations (i.e., predominantly Macroelongatoolithus). Characteristics of the Milk River ootaxa indicate that they are ascribable to at least one ornithopod and four small theropod species. The taxonomic affinity of the eggshell assemblage is consistent with the dinosaur fauna known based on isolated teeth and fragmentary skeletal remains from the formation, although most ornithischians and large theropods are not represented by eggshell. Relative to the Milk River Formation eggshell, similar oospecies occurring in younger Cretaceous deposits tend to be somewhat thicker, which may reflect an increase in body size of various dinosaur lineages during the Late Cretaceous.     

Planktonic foraminifera and calcareous nannofossils record in the upper Campanian-Maastrichtian pelagic deposits of the Malatya Basin in the Hekimhan area (NW Malatya,eastern Anatolia)

The uppermost Cretaceous (upper Campanian-Maastrichtian) pelagic successions from the Malatya Basin (NW Malatya, eastern Anatolia) were studied by 688 samples, which were collected from five stratigraphic sections in the Hekimhan area. The pelagic deposits conformably overlie rudist bearing shallow-water limestones and are overlain conformably by Maastrichtian dolomites and unconformably by Paleocene-Eocene deposits, respectively.The pelagic successions in the Hekimhan area comprise the Kösehasan Formation at the base and the Zorbehan Formation at the top and reach up to 1100 m in thickness. The Kösehasan Formation rests over the neritic rudist-bearing limestones of the Güzelyurt Formation along a sharp contact and consists mainly of flysch-type sandstone-mudstone alternation with complete and partial Bouma sequences. The carbonate content of abundant planktonic foraminifera and nannoplankton-bearing 980-m-thick succession increases upwards and the formation passes gradually to the clayey limestones and marlstones of the Zorbehan Formation to the top. Occurrences of nannoplankton Lithraphidites quadratus Bramlette and Martini and Micula praemurus (Bukry) in the first beds of the Kösehasan Formation indicate that the age of the Kösehasan Formation and overlying Zorbehan Formation is of late Maasthrichtian. Another late Maastrichtian taxa Cribrosphaerella daniae Perch-Nielsen and Arkhangelskiella maastrichtiana Burnett are observed from the lowermost part of the succession. Maastrichtian planktonic foraminifera such as Contusotruncana walfischensis (Todd) and Globotruncanita pettersi (Gandolfi) were recorded through the successions. Although planktonic foraminifera are diverse and abundant particularly in the Kösehesan Formation, index late Maasthrichtian species were not encountered. Campanian and Santonian-Campanian planktonic foraminifera, e.g. Radotruncana calcarata (Cushman) and Globotruncanita elevata (Brotzen), obtained particularly from the lower part of the succession and calcareous nannofossils such as Broinsonia parca parca Bukry, Reinhardtites anthophorus (Deflanre) and Eiffellithus eximius (Stover) are interpreted as reworked from older strata. Trace fossils are common throughout the succession.Rareness of planktonic foraminifera and nannoplankton in the uppermost part of the succession (Zorbehan Formation) indicates maximum shallowing of the latest Maastrichtian sea in this part of the basin. Rare echinoids, bivalves and ammonites are observed in that part of the sequence.The obtained data indicate that sediment accumulation rate of the pelagic deposits is rather high and about 27.5 cm/ky for this part of the basin. Changes in thickness of the formations along short distances in the five stratigraphic sections analysed in this study should be related to the diachroneity of the depositional and erosional events.     

Constraining the age of the last marine sediments in the late Cretaceous of central south Pyrenees (NE Spain): Insights from larger benthic foraminifera and strontium isotope stratigraphy

The uppermost Cretaceous (upper Campanian–Maastrichtian) marine deposits of the central south Pyrenees host a rich larger benthic foraminiferal fauna and several rudist-rich levels. These marine deposits are directly overlain by the continental facies of the Arén and Tremp Formations, which are famous for their fossil dinosaur remains. Larger benthic foraminiferal distribution documents an important faunal turnover in all the carbonate platform environments within the photic zone, from open marine to littoral areas. Biostratigraphy indicates that this turnover occurred close to the Campanian-Maastrichtian boundary. This is also confirmed by strontium isotope stratigraphy which indicates an earliest Maastrichtian age for the appearance of the larger benthic foraminiferal assemblage constituted by Lepidorbitoides socialis, Clypeorbis mammillata, Wannierina cataluniensis, Orbitoides gruenbachensis, Siderolites aff. calcitrapoides, Fascispira colomi, Omphalocyclus macroporus and Laffiteina mengaudi. In particular, a numerical age of 71 Ma is obtained for the Hippurites radiosus level, just a few meters below the first continental deposits of the Arén sensu stricto Formation. The youngest marine sediments of the central south Pyrenees are early Maastrichtian in age. This is also an important constraint for the age of the end-Cretaceous dinosaur fossil localities of the Tremp basin.     

Agglutinated foraminifera from the Campanian-Maastrichtian Kiseiba Formation in the Kurkur area,Egypt

The upper Campanian to upper Maastrichtian sedimentary sequence of the Kiseiba Formation in south Western Desert is sampled and described in two surface sections (Sinn El Kaddab and Wadi Abu Siyal). Forty-four agglutinated foraminiferal species are identified from 42 samples in the studied succession. The benthic foraminiferal assemblages are dominated by agglutinated foraminifera which comprise more than 90% of the assemblage. The agglutinated foraminifera are subdivided into five morphogroups (A, B, C, D, E) according to shell architecture, integrated with the supposed microhabitat and feeding strategy. The foraminiferal assemblage is assigned to mixohaline shallow water environments. These assemblages with Ammoastuta megacribrostomoides and Ammotium bartheli suggest lagoonal environments with considerably reduced salinity in warm climates and high runoff for the late Campanian-Maastrichtian interval.     

Stratigraphy,sedimentology and tectonic evolution of the Upper Cretaceous/Paleogene succession in north Eastern Desert,Egypt

The stratigraphy, sedimentology and syn-depositional tectonic events (SdTEs) of the Upper Cretaceous/Paleogene (K–P) succession at four localities in north Eastern Desert (NED) of Egypt have been studied. These localities are distributed from south-southwest to north-northeast at Gebel Millaha, at North Wadi Qena, at Wadi El Dakhal, and at Saint Paul Monastery. Lithostratigraphically, four rock units have been recorded: Sudr Formation (Campanian–Maastrichtian); Dakhla Formation (Danian–Selandian); Tarawan Formation (Selandian–Thanetian) and Esna Formation (Thanetian–Ypresian). These rock units are not completely represented all over the study area because some of them are absent at certain sites and others have variable thicknesses. Biostratigrapgically, 18 planktonic foraminiferal zones have been recorded. These are in stratigraphic order: Globotruncana ventricosa Zone (Campanian); Gansserina gansseri, Contusotruncana contusa, Recimguembelina fructicosa, Pseudohastigerina hariaensis, Pseudohastigerina palpebra and Plummerita hantkenenoides zones (Maastrichtian); Praemurica incostans, Praemurica uncinata, Morozovella angulata and Praemurica carinata/Igorina albeari zones (Danian); Igorina albeari, Globanomanlina pseudomenradii/Parasubbotina variospira, Acarinina subsphaerica, Acarinina soldadoensis/Globanomanlina pseudomenardii and Morozovella velascoensis zones (Selandian/Thantian); and Acarinina sibaiyaensis, Pseudohastigerina wilcoxensis/Morozovella velascoensis zones (earliest Ypresian). Sedimentologically, four sedimentary facies belts forming southwest gently-dipping slope to basin transect have been detected. They include tidal flats, outer shelf, slumped continental slope and open marine hemipelagic facies. This transect can be subdivided into a stable basin plain plus outer shelf in the extreme southwestern parts; and an unstable slope shelf platform in the northeastern parts. The unstable slope shelf platform is characterized by open marine hemipelagic, fine-grained limestones and fine siliciclastic shales (Sudr, Dakhla, Tarawan and Esna formations). The northeastern parts are marked by little contents of planktonic foraminifera and dolomitized, slumped carbonates, intercalated with basinal facies. Tectonically, four remarkable syn-depositional tectonic events (SdTEs) controlled the evolution of the studied succession. These events took place strongly within the Campanian–Ypresian time interval and were still active till Late Eocene. These events took place at: the Santonian/Campanian (S/C) boundary; the Campanian/Maastrichtian (C/M) boundary; the Cretaceous/Paleogene (K/P) boundary; and the Middle Paleocene–Early Eocene interval. These tectonic events are four pronounced phases in the tectonic history of the Syrian Arc System (SAS), the collision of the Afro-Arabian and Eurasian plates as well as the closure of the Tethys Sea.     

Upper Campanian-lower Maastrichtian sections of the northwestern Rostov region. Article 1. Description, paleontological assemblages, and lithobiostratigraphy

Four upper Campanian-lower Maastrichtian reference sections are described in the Glubokaya and Kalitva river basins and in the Znamenka 1-A Borehole located in the northwestern Rostov region. The sections are composed of the upper Campanian Kagal??nik, Belgorod, Pavlovka, Sukhodol and lower Maastrichtian Efremovo-Stepanovka formations. They are characterized by successive stratigraphically significant macro- and microfossil assemblages: belemnites, calcareous nannoplankton, benthic foraminifers, and radiolarians. The Pavlovka and, particularly, Sukhodol formations contain a specific assemblage of coarsely-agglutinated benthic foraminifers. The first data obtained on radiolarians in upper Campanian-lower Maastrichtian sections of the northwestern Rostov region revealed four assemblages, two of which were previously unknown from Upper Cretaceous sediments of the East European Platform. Most sections enclose a hiatus at the base of the Sukhodol Formation, which comprises two upper Campanian benthic foraminiferal zones. The problem of recognition of the lower Maastrichtian boundary on the East European Platform is considered in accordance with international GSSP requirements.     

Biostratigraphy of the Tethyan cretaceous successions from northwestern Zagros fold–thrust belt,Kurdistan region,NE Iraq

Nineteen benthonic and planktonic foraminiferal zones and their subzones have been recognized in the Tethyan cretaceous successions along the four sections analyzed in the northwestern Zagros fold–thrust belt within the preforeland–foreland basin. A detailed micropaleontological investigation revealed eight benthonic zones from the Qamchuqa Formation (Barremian to Lower Early Cenomanian) including: the Choffatella decipiens interval zone, C. decipiens/Palorbitolina lenticularis total range zone, C. decipiens/Salpingoporella dinarica interval zone, Mesorbitolina texana total range zone, Mesorbitolina subconcava total range zone, Orbitolina qatarica total range zone, Orbitolina sefini total range zone, and the Orbitolina concava partial range zone. The Rotalipora cushmani total range zone was recorded in the Dokan Formation that overlies the Qamchuqa Formation of the Late Cenomanian age. The Gulneri Formation is represented only by the Whitnella archaeocretacea partial range zone/Heterohelix moremani total range subzone and indicates the Late Cenomanian/Early Turonian age. Six planktonic foraminiferal zones were recorded from the Kometan Formation, indicating the Late Cenomanian to Early Campanian age, and are represented by the R. cushmani/H. moremani subzone, Helvetotruncana helvetica total range zone, Marginotruncana sigali partial range zone, Dicarinella primitiva interval range zone, Dicarinella concavata interval zone, Dicarinella assymetrica total range zone, and Globotruncanita elevata partial range zone. Two planktonic foraminferal zones were recorded also and these are related to the Globotruncana (fornicata, stuartiformis, elevata, and ventricosa) assemblage zone, Globotruncana calcarata total range subzone, from the Shiranish Formation, Lower Late Campanian, while the second zone is nominated as the Globotruncana (arca, tricarinata, esnehensis, and bahijae) assemblage zone, Globotruncana gansseri interval subzone, and Globotruncana contusa total range zone of the Late Campanian to basal middle Maastrichtian age. The last zone is related to the Abathomphalus mayaroensis partial range zone (of Late Maastrichtian age) and occasionally intercalated with the Orbitoides–Loftusia benthic zones. An important hiatus, between the Qamchuqa and Kometan formations was proved and manifests Pre-Aruma unconformity, and is occasionally associated with the global Cenomanian–Turonian Oceanic Anoxic Euxinic Event, while the Maastrichtian red bed of the Shiranish Formations mostly points to Tethyan upper Cretaceous Oceanic Red Bed.