Permian and Triassic radiolarians from chert breccia in the Nong Prue area,western Thailand: its origin and depositional setting in the Paleotethys

Bedded chert and siliceous shale successions previously regarded as the Silurian–Devonian rock units, distributed in the Nong Prue area, northwest of Kanchanaburi, western Thailand, yielded Lopingian (upper Permian) and Lower–Middle Triassic radiolarians. We found chert breccia layers in northern Nong Prue area, mainly consisting of angular to sub-angular chert clasts with matrices of silt-sized chert grains and clay minerals. We discriminated uppermost Pennsylvanian–Lopingian (upper Carboniferous–upper Permian) and Middle Triassic radiolarian-bearing chert clasts from four different levels of the chert breccia; 28 species of 15 genera with one radiolarian gen. et sp. indet. are identified. On the basis of sedimentary characteristics of the chert breccia, we suggest that the chert breccia is of sedimentary origin. The radiolarian assemblages reported here, together with previously known lithological and paleontological evidence, further indicate that the chert breccia was deposited in the Paleotethys with chert clasts derived from fine grained siliceous rocks in the continental margin to deep ocean basin of the Sibumasu Terrane.     

First evidence of Late Carnian radiolarians from the Izmir-Ankara suture complex, central Sakarya, Turkey: implications for the opening age of the Izmir-Ankara branch of Neo-Tethys

Within the Late Cretaceous mélange complex of the Izmir-Ankara suture zone in central Sakarya area, north-western Turkey, a megablock with radiolarian cherts associated with basaltic pillow lavas has been dated by radiolarians. The studied radiolarian assemblage and conodonts yielded an early Late Carnian age. This age is the oldest obtained from the chert blocks all along the suture belt and has important implications for the rifting/opening age of the Izmir-Ankara branch of the Tethys ocean in north-western Turkey. Based on this new data, it is concluded that during the Late Triassic the Izmir-Ankara seaway was connected to the other Tethyan oceanic branches and deep enough to provide chert sedimentation and exchange radiolarians with the main open oceans. It is further suggested that the long-lasting misinterpretation of a Liassic rifting/opening of the Izmir-Ankara ocean should be revised.     

西藏南部放射虫微体古生物研究进展

西藏南部的雅鲁藏布蛇绿岩带以及该带之南的沉积地层带（特提期沉积区,北喜马拉雅亚区）中广泛发育着大量含放射虫地层,放射虫研究在确定该区蛇绿岩的形成时代,解释造山带复杂的地层层序以及揭示印度板块与欧亚板块在古近纪碰撞老祖宗前的古海洋盆地的演化历史等方面发挥了重要作用。根据已发表的文献以及我们正在进行中的初步成果显示,藏南地区的含放射虫地层的时代分布之中三叠世（安尼期）至晚白垩（土仑期）。这些地层的岩性包括硅质岩,硅质泥岩,凝灰质细碎屑岩和泥晶灰岩等,尽管藏南的放射虫研究已取得一些成果,但系统的放射虫研究与地层研究仍然有待于进一步深入开展。     

藏南泽当雅鲁藏布缝合带中的三叠纪放射虫

西藏南部泽当西金鲁村附近发现的一套硅质岩含有两个放射虫化石组合：Capnuchosphaera triassica组合和Pseudostylosphaera nazaroui组合。这些放射虫化石可以同中三叠世拉丁期至晚三叠世卡尼期放射虫动物群对比,这套硅质岩为一外为岩体,包括在由高劈理化泥岩组成的混杂岩基质中,这是雅鲁藏布江缝合带三叠纪放射虫的首次报道。     

Cretaceous (Albian to Turonian) radiolarians from chert blocks of the Moni Mélange (Southern Cyprus)

Well-preserved Cretaceous (Albian–Turonian) radiolarians were extracted from radiolarian-bearing chert olistoliths of the Monagroulli Member within the Moni Mélange (Campanian-Maastrichtian, Southern Cyprus). Four assemblages were distinguished: Middle Albian–Lower Cenomanian (Thanarla spoletoensis Zone), Upper Albian–Lower Cenomanian (Thanarla spoletoensis Zone, Dorypyle? anisa Subzone), lowermost Turonian (base of Alievium superbum Zone) and Lower Turonian (Alievium superbum Zone). The radiolarian assemblages are diverse and have taxonomic composition similar to coeval assemblages of Italy and Spain. The sediments of the Monagroulli Member differ from coeval rocks of the Mamonia Complex (western Cyprus) by the more common presence of radiolarian cherts and may have been formed in the distal part of a continental margin with less input of clastic material. A new spicular radiolarian genus Cyprothamnus with 2 new species (C. multifurcatus and C. moniensis) is described from the Lower Turonian strata.     

Mesozoic Radiolaria of Bosnia and Serbia: New data

Jurassic and Cretaceous radiolarian faunas were discovered in bedded chert of the Dinaric and Vardar tectonic zones of Bosnia and Herzegovina. Only Triassic radiolarians have previously been described in Bosnia and Herzegovina, while the finds of Bajocian, Bathonian-Callovian, Oxfordian-Kimmeridgian, Tithonian-Berriasian, and Campanian are new. Additional localities of Triassic and Jurassic radiolarians were investigated in Serbia. By correlation with radiolarians from the previous studies within Serbia, the Late Aalenian-Bajocian and Bathonian-Callovian Serbian radiolarian beds are newly dated. The first find of Cretaceous radiolarians in Serbia is reported. The oldest Mesozoic Radiolaria-bearing formations outcropping in the Western Belt of the Vardar Zone are dated Mid-Upper Triassic. The youngest radiolarians come from the Upper Cretaceous (Campanian) of the northern part of this belt of the Vardar Zone, where they co-occur with planktonic foraminifers. The distribution of 70 radiolarian samples within sections is shown. The taxonomic composition of 39 samples is analyzed. Radiolarian species extracted from 13 samples are described and figured. The list of 72 taxa and 3 plates of Jurassic radiolarians of Bosnia and Herzegovina, 3 plates of Triassic, 1 plate of Middle Jurassic, and 1 plate of Upper Cretaceous radiolarians of Serbia are presented.     

Morphological characteristics of boreal radiolarians from the Triassic and Late Cretaceous: Comparative analysis

When comparing boreal radiolarian assemblages of the Triassic and Late Cretaceous, significant differences in their morphotypic composition are recognized. In particular, Triassic assemblages are dominated by spherical morphotypes, including pylomate forms of the genus Glomeropyle, while Late Cretaceous assemblages are dominated by prunoid morphotypes without polar spines (genera Prunobrachium and Amphibrachium). It is concluded that, in the course of evolution, high-latitude radiolarian assemblages considerably changed both taxonomically and morphologically. Therefore, it is impossible to determine the uniform morphological and taxonomic characters describing boreal assemblages of the entire Mesozoic. Features of boreal radiolarian assemblages are unique to each geological epoch.     

Palaeocology of Hard Substrate Faunas from the Cretaceous Qahlah Formation of the Oman Mountains

Skeletal encrusters and carbonate hardgrounds are rare in siliciclastic sands and gravels because of high levels of abrasion and sediment movement. An exception to this is the Maastrichtian Qahlah Formation of the Oman Mountains, a sequence of coarse siliciclastic sediments deposited on a shallow marine shelf above wavebase and at an equatorial palaeolatitude. This unit contains intercalated carbonate hardgrounds and other hard substrates which were encrusted and bored. The hard substrates, comprising carbonate and silicate clasts, calcareous bioclasts (mollusc shells and coral fragments) and wood, supported a diverse encrusting and boring fauna dominated in biomass by the oyster Acutostrea . There are twelve bryozoan species and at least two serpulid worm species, most living cryptically. Other encrusters on exposed surfaces include the agglutinated foraminiferan Placopsilina and several species of colonial corals. Borings in the carbonate clasts and shells are predominantly those of bivalves ( Gastrochaenolites ), with subsidiary clionid sponge ( Entobia ) and acrothoracican barnacle ( Rogerella ) borings. The woodgrounds are thoroughly bored by teredinid bivalves ( Teredolites ). Of the common substrate types, carbonate hardground clasts support the greatest number of taxa, followed by chert clasts, with limestone rockground pebbles being depauperate. Clast composition and relative stability probably explain these differences. Individual clasts probably had variable and typically long colonisation histories. Detailed palaeoecological interpretation is constrained by taphonomic loss, time-averaging and clast transportation and reorientation. Evidence from the Qahlah Formation shows that tropical rocky-shore biotas in the Cretaceous were not impoverished as previously believed.     

Latest Cretaceous to Late Paleocene radiolarian biostratigraphy: A new zonation from the New Zealand region

The scarcity of records of Early Paleocene radiolarians has meant that while radiolarian biostratigraphy is firmly established as an important tool for correlation, there has been a long-standing gap between established zonations for the Cretaceous and from latest Paleocene to Recent. It has also led to considerable speculation over the level of faunal change across the Cretaceous/Tertiary (K/T) boundary. Consequently, the discovery of rich and diverse radiolarian assemblages in well-delineated K/T boundary sections within siliceous limestones of the Amuri Limestone Group in eastern Marlborough, New Zealand, is of great significance for biostratigraphy and K/T boundary research.This initial report is restricted to introducing a new latest Cretaceous to mid Late Paleocene zonation based on the radiolarian succession at four of these sections and a re-examination of faunas from coeval sediments at DSDP Site 208 (Lord Howe Rise). Three new Paleocene species are described:Amphisphaera aotea, Amphisphaera kina andStichomitra wero. Six new interval zones are defined by the first appearances of the nominate species. In ascending order these are:Lithomelissa? hoplites Foreman (Zone RK9, Cretaceous),Amphisphaera aotea n. sp. (Zone RP1, Paleocene),Amphisphaera kina n. sp. (RP2),Stichomitra granulata Petrushevskaya (RP3),Buryella foremanae Petrushevskaya (RP4) andBuryella tetradica (RP5). Good age control from foraminifera and calcareous nannofossils permits close correlation with established microfossil zonations. Where age control is less reliable, radiolarian events are used to substantially improve correlation between the sections.No evidence is found for mass extinction of radiolarians at the end of the Cretaceous. However, the K/T boundary does mark a change from nassellarian to spumellarian dominance, due to a sudden influx of actinommids, which effectively reduces the relative abundance of many Cretaceous survivors. An accompanying influx of diatoms in the basal Paleocene of Marlborough, together with evidence for an increase of total radiolarian abundance, suggests siliceous plankton productivity increased across the K/T boundary. Possible causes for this apparently localised phenomenon are briefly discussed.     

Foraminifera,Radiolaria and Conodont assemblages from the Early Mississipian (late Tournaisian)/Early Pennsylvanian (early Bashkirian) blocks within the Mersin Mélange,southern Turkey: Biochronological and paleogeographical implications

The Mersin Mélange, a sedimentary complex in southern Turkey, includes blocks of various origins within a Late Cretaceous matrix. Two blocks in the Mersin Mélange are herein recognized to be of Carboniferous age. One block (the Kozan Block) is composed of alternating chert and mudstone, and includes radiolarian and conodont assemblages revealing a late Tournaisian (Early Mississippian) age. The other (Keven-West Block) consists of platform carbonate containing abundant foraminifera indicating Bashkirian (Early Pennsylvanian) age. These dates are so far the oldest obtained from the blocks within the Mersin Mélange. A correlation of the lithostratigraphies of blocks in the Mersin Mélange with the coeval Tauride sequences indicates that they correspond to the successions in the Beysehir-Hoyran Nappes. In these nappes, the late Tournaisian is characterized by radiolarian rich chert and mudstone of an open marine environment, whereas the Bashkirian succession represents a shallow water environment with Foraminifera-bearing limestone. The Tournaisian deepening can be ascribed to the opening of a deep marginal basin to the north of the Tauride Platform and uplifting of the northern Tauride-Anatolide Platform margin during the Late Mississippian and Early Pennsylvanian.A shallowing upward sequence started in the Tournaisian with a pelagic sequence followed by platform carbonates of Bashkirian age in the Beysehir-Hoyran Nappes, and could be related to a major glaciation event during late Visean–Serpukhovian resulting in a sea-level drop and deposition of platform carbonates in the Bashkirian. Given the stratigraphic properties of northerly originated nappe packages (Cataloturan, Hadim and Bolkardag) and parautochthonous/autochthonous sequences in Taurides, sedimentation on the Tauride-Anatolide Platform mainly terminated after the Moscovian, except in the Hadim Nappe with sedimentation in a very shallow sea conditions until the end of the Permian. A depositional break corresponding to the Kasimovian–Wordian time interval in these sequences in the Tauride-Anatolide Platform could be related to the effects of both late Paleozoic Gondwanan glaciation and a possible mantle plume occurrence evidenced by the geochemistry of lavas in the Mersin Mélange causing major uplift in the Northern NeoTehys Ocean. However; at the center of the plume, pelagic sequences (e.g., ribbon chert and pelagic limestone) were deposited associated with these lavas due to a progressive developing rift system during the Permian, based on previous studies.     

Middle and Late Triassic radiolarians from northern Tibet: Implications for the Bayan Har Basin evolution

During the Triassic, the Bayan Har Basin is a huge triangular basin surrounded by the North China Platform, South China Platform and Qingtang Terrane. It is filled by a Triassic turbidite sequence, the Bayan Har Group. For a long time, the series of Bayan Har Group in the eastern part of the basin were considered to be a Lower to Upper Triassic sequence, and in the western part, was attributed to the Upper Triassic. A well-preserved diversified radiolarian fauna was recovered from radiolarian chert and tuffite interbeds of the Bayan Har Group turbidites and adjacent stratigraphic units in the Hoh Xil area, northern Tibet. Sixty-seven species are identified and subdivided into two assemblages: late Anisian and early Carnian. Combined with the discovery of the Late Permian and Early Triassic turbidite in the Bayan Har Group in this area by Huang et al., it proves that all the Triassic is also present in the Bayan Har Group sequence in the western part. The evolution of the Bayan Har Basin may be traced back to the Late Permian. The massive sequence of the Bayan Har Group and its provenance indicate that the Kunlun and Qinling orogenic belts rapidly rise during the Middle-Late Triassic. The basin extended to the end of the Triassic, possibly locally to the Jurassic.     

Paleobiota from the Deccan volcano-sedimentary sequences of India: paleoenvironments,age and paleobiogeographic implications

Paleobiotic assemblages from the Deccan infra- and intertrappean beds are reviewed in great detail. Three distinct paleoenvironments (fluvio-lacustrine/terrestrial, brackish water and marine) have been identified within the infra- and intertrappean biotic assemblages of peninsular India. Recently, marine incursions have been recorded in a few of the Deccan intertrappean beds exposed in central and south-eastern India. The intertrappean beds have yielded marine planktic foraminiferans and freshwater/brackish water ostracods. The affinities of the paleobiotas are commonly considered to show a mixed pattern resulting from the addition of Gondwanan and Laurasian elements to endemic Indian taxa. During the last four decades, various biogeographic models (southern and northern connections) have been proposed to explain the presence of anomalous biogeographic biota in the Late Cretaceous of India. Based on the recovered fauna and flora assemblages, the Cretaceous–Paleogene boundary has been marked and a Late Cretaceous to Early Paleocene age has been assigned to these Deccan volcano-sedimentary sequences.     

Provenance of the Hangu Formation,Lesser Himalaya,Pakistan: Insight from the detrital zircon U-Pb dating and spinel geochemistry

Clastic rich Hangu Formation of the Early Paleocene exposed at the apex of Hazara-Kashmir syntaxis, is significant in providing evidence of the regional Mesozoic–Cenozoic unconformity and nature of detritus supplied. The current study focuses on U-Pb age dating of the detrital zircons along with spinel geochemistry to interpret tectonic implications on provenance. The Hangu Formation is composed of coarse grained sandstone, arenaceous limestone, carbonaceous shale and laterite around the Paras region and rests unconformably over Mesozoic Samana Suk Formation. The probability density plots of the detrital zircons of the Hangu Formation exhibit strong similarity to the Tethyan Himalayan detrital record. The younger Mesozoic detrital zircons exhibit resemblance to Tethyan Himalayan as well as ophiolitic detrital suites, but are very few compared to their coeval Stumpata, Jidula and Denggeng/Sangdanlin formations. The quantitative comparison reflects strong resemblance to the Tethyan Himalaya, whereas, the ophiolitic component relationship is quite poor. Comparison of spinel geochemical data with Northwestern ophiolites (Chilas Ophiolites) and Tethyan Himalaya exhibits mixed source regime of the Hangu sediments. However, the combined U-Pb dating, sandstone petrography and spinel geochemical data suggest that the detritus of the Hangu Formation is mainly derived from the Tethyan Himalayan source (Indian source). The absence of ophiolitic signature in petrography and U-Pb geochronology may suggest that the northern ophiolites were not exposed to provide detritus to the Early Paleocene Hangu Formation. This may also be interpreted that the ophiolites were emplaced during the Late Cretaceous on the northern Indian margin but uplifted and eroded later with the final India–Eurasia collision, which is clearly recorded in various studies all along the Indian margin. This fact also intimates the ophiolite emplacement as a possible cause of the regional Mesozoic–Cenozoic unconformity.     

Late Triassic, Early and Middle Jurassic Radiolaria from ferromanganese-chert ‘nodules’ (Angelokastron, Argolis, Greece): evidence for prolonged radiolarite sedimentation in the Maliac-Vardar Ocean

In the Argolis, the Basal Sequence, constituting the eastern Pelagonian margin which bordered the Maliac-Vardar oceanic domain, includes shallow-water carbonates of Late Triassic-Early Jurassic, condensed pelagic limestones of Early-Middle Jurassic, radiolarian cherts of late Middle-Late Jurassic age and siliceous mudstones and sandstones rich in ophiolite fragments. Up-section, coarse breccias, including clasts of boninites derived from the ophiolite obducted onto the Pelagonian margin in Late Jurassic times crop out. Near Angelokastron a small quarry exposes pervasively sheared dark reddish-brown, radiolarian-bearing cherty shales with disrupted fragments of chert and chert nodules impregnated by ferro-manganese oxides. These shales occur in the footwall of a thrust bringing them into contact with the Pantokrator Limestone of the Basal Sequence. We collected more than 30 samples of the chert fragments and the shaly matrix. Thirteen nodules and one matrix sample yielded determinable radiolarians. Low to non-detectable concentrations of trace metals such as Co, Cr, Cu, Ni, Zn, and Pb indicate a hydrothermal origin of the ferro-manganese mineralization. The radiolarian taxa found indicate four age groups for the nodules that are embedded in the siliceous shale matrix that yielded a Middle Jurassic age (middle Bathonian). The first group includes a nodule of Late Triassic age (late Norian to Rhaetian); the second group nodules of Early Jurassic age (late early to late Pliensbachian and probably middle-late Toarcian); the third group nodules of early Middle Jurassic age (Aalenian–Bajocian); the last group finally includes nodules of late Middle Jurassic age (Bajocian–Bathonian). The presence of Upper Triassic to Middle Jurassic Mn-impregnated chert nodules in a Middle Jurassic matrix indicates a deep oceanic environment of deposition outside the Pelagonian realm (easternmost Adria Plate), which at that time was a shallow-water carbonate platform with a thin pelagic limestone cover. The chert nodules are with all certainty derived from the oceanic Maliac-Vardar domain and were, together with their host formation, tectonically emplaced onto the Pelagonian margin. We speculate that these nodules, more lithified than their matrix, were exhumed on the slope of an intra-oceanic accretionary wedge and were redeposited in the Middle Jurassic siliceous mudstones on the floor of the subducting Maliac-Vardar Ocean.     

CRETACEOUS PLANKTONIC FORAMINIFERA FROM BORNHOLM AND THEIR ZOOGEOGRAPHIC SIGNIFICANCE

Late Cretaceous formations exposed along the south coast of Bornholm Island, Denmark, contain well preserved assemblages of planktonic foraminifera, which are described and illustrated. Two taxa, Whiteinella baltica and Hedbergella bornholmensis , are described as new. The oldest assemblage, Middle to early Upper Cenomanian in age, is essentially monospecific and indicative of a restricted pelagic environment. The overlying Lower Senonian faunules are diverse, contain large populations which are associated with other pelagic microfossils, and provide a more typical example of Boreal planktonic foraminiferal associations. Taxonomically the assemblages are largely composed of species of Hedbergella, Whiteinella, Archaeoglobigerina, Globigerinelloides , and Heterohelix and double-keeled species of Globotruncana , particularly G. marginata. These species are widely distributed in space and time. Thus Bornholm assemblages have a cosmopolitan aspect, which can be identified in microfaunas from the Western Interior of North America and Alaska. Because of the lower diversity, lack of restricted stratigraphic markers, Lower Senonian correlations between Bornholm, and probably Boreal pelagic microfaunas generally, coeval Tethyan assemblages are less precise than within the Tethys.     

Snapshot of an early Paleoproterozoic ecosystem: Two diverse microfossil communities from the Turee Creek Group,Western Australia

Eighteen microfossil morphotypes from two distinct facies of black chert from a deep‐water setting of the c. 2.4 Ga Turee Creek Group, Western Australia, are reported here. A primarily in situ, deep‐water benthic community preserved in nodular black chert occurs as a tangled network of a variety of long filamentous microfossils, unicells of one size distribution and fine filamentous rosettes, together with relatively large spherical aggregates of cells interpreted as in‐fallen, likely planktonic, forms. Bedded black cherts, in contrast, preserve microfossils primarily within, but also between, rounded clasts of organic material that are coated by thin, convoluted carbonaceous films interpreted as preserved extracellular polymeric substance (EPS). Microfossils preserved within the clasts include a wide range of unicells, both much smaller and larger than those in the nodular black chert, along with relatively short, often degraded filaments, four types of star‐shaped rosettes and umbrella‐like rosettes. Large, complexly branching filamentous microfossils are found between the clasts. The grainstone clasts in the bedded black chert are interpreted as transported from shallower water, and the contained microfossils thus likely represent a phototrophic community. Combined, the two black chert facies provide a snapshot of a microbial ecosystem spanning shallow to deeper‐water environments, and an insight into the diversity of life present during the rise in atmospheric oxygen. The preserved microfossils include two new, distinct morphologies previously unknown from the geological record, as well as a number of microfossils from the bedded black chert that are morphologically similar to—but 400–500 Ma older than—type specimens from the c. 1.88 Ga Gunflint Iron Formation. Thus, the Turee Creek Group microfossil assemblage creates a substantial reference point in the sparse fossil record of the earliest Paleoproterozoic and demonstrates that microbial life diversified quite rapidly after the end of the Archean.     

The Early Cretaceous of North-East Greenland: A crossroads of belemnite migration

Recent field work in Lower Cretaceous successions of Traill Ø and Wollaston Forland, North-East Greenland, have resulted in c. 2350 belemnite guards collected bed-by-bed from the upper Ryazanian – Hauterivian. The most common belemnite genera observed, Acroteuthis, Pachyteuthis, and Cylindroteuthis are of boreal-arctic affinities and closely related to NW European and Siberian faunas. Other taxa, including Hibolithes (common), Pseudobelus (relatively common) and Duvalia (rare), show faunal links to both NW European and Mediterranean faunas. This paper describes and discusses these findings in their taxonomic, biostratigraphic, palaeobiogeographic, palaeoecologic and palaeoceanographic context. In particular, the occurrence of Pseudobelus which is common in the circum Mediterranean area, is remarkable since it is the first observation of this Tethyan genus in the entire Boreal Realm. The palaeoecological interpretation of these observations result in the recognition of four different palaeobiogeographic belemnite assemblages for the Boreal Realm: 1) North-East Greenland, 2) Spitsbergen, 3) NW Europe and 4) Siberia. In contrast to the other assemblages, the belemnite faunas of North-East Greenland consist of a) Boreal-Arctic elements, b) Boreal-European taxa, c) endemic belemnites of Tethyan ancestry, and d) Tethyan species. These findings make North-East Greenland part of an immigration route from the Tethyan Realm via the north Atlantic to the high Boreal. This allowed Tethyan species, which are otherwise unknown from the Boreal Realm, to reach North-East Greenland. The occurrence of the Tethyan genus Pseudobelus in North-East Greenland also supports the interpretation of this taxon as a hemipelagic dweller, capable of crossing major distances. The belemnite patterns further suggest the existence of a proto Gulf-stream, documenting a south-to-north flow of warm surface waters as far north as Greenland already in the earliest Cretaceous (Valanginian). This has substantial implications for the interpretation of Early Cretaceous climate and oceanic current systems, as well as for the palaeobiology of belemnites.     

Recent approach to Buchia biostratigraphy from the Tethyan Himalaya area, China

Recent collections from six sections in Lanongla area,Tethyan Himalaya allow the establishment of four buchia assembles.In ascending they are Buchia-Buchia spitiensis,Buchia masquensis-Buchia rugasa,Buchia blanfordiana,Buchia piochii and Buchia subokensis assemblages.These Buchia assemblages first demonstrate that not only the Upper Jurassic strata but also the highest Buchia assemblage-Buchia subokensis,which appeared in Lower Cretaceous strata all over the world are present in Lanongla area.This first records the highest Buchia assemblage in Lanongla area.     

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.