First occurrence of azhdarchoid pterosaurs in the Gault Formation (Lower Cretaceous,Albian) of England,United Kingdom with a brief review of Gault pterosaurs

Pterosaurs are a rare component of the Early Cretaceous (Albian) Gault Formation of southern England. The only named taxon reported, ‘Pterodactylus’ daviesii Owen, 1874, is widely regarded as a nomen dubium or as Pterodactyloidea incertae sedis, while most other material can be referred to Pterodactyloidea indet. Here we describe a fragmentary humerus and elongate mid-series cervical vertebra both from the Gault Formation of Kent, southeast England that can be referred to the edentulous pterodactyloid clade Azhdarchoidea. The cervical vertebra is identified as being from a non-tapejaromorph azhdarchoid on account of its reduced neural spine, a neural arch confluent with the centrum, a neural canal that is subsumed into the centrum and the lack of foramina on the lateral surfaces of the centrum. The humerus is referred to Azhdarchoidea on account of its sub-rectangular distal end.     

The stratigraphy of the Gault and Upper Greensand Formations (Albian stage,Cretaceous) of the Dorset and East Devon Coast World Heritage Site,U.K.

The Upper Greensand Formation, in part mainly underlain by the Gault Formation and overlain by the Chalk Group, has extensive cliff outcrops in the Dorset and East Devon Coast World Heritage Site (WHS). The argillaceous Gault, up to 20 m thick in the Isle of Purbeck, is poorly exposed due to its involvement in extensive landslides, but the exposures of Upper Greensand are the most complete in England. The Gault (Middle Albian) rests unconformably on progressively older Jurassic and Triassic strata when traced westwards and becomes more arenaceous in the same direction. On the east Devon coast, the Upper Greensand comprises up to 55 m of sandstones and calcarenites that were deposited in fully marine, shallow-water environments. The formation is divided into three members there (Foxmould, Whitecliff Chert and Bindon Sandstone) each bounded by a prominent erosion surface. The full thickness of the Upper Greensand, up to 60 m, was formerly exposed in cliffs in the Isle of Purbeck in and adjacent to the steeply dipping limb of the Purbeck Monocline. The lower (Foxmould) part of the succession is similar to that in east Devon, but the upper part (White Nothe Member) is lithologically different and probably the correlative of only the Bindon Sandstone. Much of the fauna of the Gault and Upper Greensand of the WHS is not age-diagnostic with the result that the ages of parts of the succession are still poorly known. However, diverse ammonite assemblages recorded from a few thin beds in the lower and highest parts of the succession show that all except one of the Albian ammonite zones is present.     

An Early Albian Arctic-type ammonite Arcthoplites from Hokkaido,northern Japan,and its paleobiogeographic and paleoclimatological implications

An Early Albian Arctic-type ammonite Arcthoplites was discovered from the Kamiji Formation of the Yezo Group in the Nakagawa area, northern Hokkaido, northern Japan. This is the first reliable record of a hoplitid ammonite from Japan and clearly indicates the distribution of an Arctic fauna in the middle latitudes of the North Pacific at that time. Synchronously with the appearance of this Arctic-type ammonite, the tropical Tethyan biota (Mesogean taxa) disappeared from Hokkaido and elsewhere in the Northwest Pacific. These biogeographic changes suggest the existence of a “cooling” episode in the Early Albian North Pacific.     

Early lithification and hardgrounds in upper Albian and Cenomanian calcarenites,southwest England

Early diagenetic lithification of calcarenites on the sea floor led to the development of a variety of hardgrounds, intraformational conglomerates, breccias and boulder beds in southwest England during late Albian and Cenomanian time. Cemented nodules commonly developed below the sea floor, and these were avoided by burrowing infauna. In some instances the nodules were exhumed and reworked on the sea floor to form distinctive intraformational conglomerates; exposed nodules frequently became bored and encrusted by organisms and mineralised by glauconite and phosphate. In other cases, sea floor cementation produced true hardgrounds whose upper surfaces were affected by the same processes, but the hardened layers were only a few tens of centimetres thick and were underlain by soft sediment. Fracturing and brecciation of some hardground layers occurred through differential compaction and through undermining and collapse as the result of burrowing and erosion beneath the hardened layer. Reworking of clasts produced in this manner yielded intraformational breccias. Petrographic analysis reveals multiple generations of carbonate cement, commonly beginning with syntaxial overgrowths on echinoderm fragments and “dog tooth” spar on polycrystalline carbonate grains. A progression exists in the Albian-Cenomanian succession of southwest England from relatively simple hardgrounds and intraformational conglomerates low in the sequence up into complex hardgrounds that may record many stages of sediment accretion, cementation, mineralisation and erosion. This progression appears to record increasing water depths and increased sea floor diagenesis.     

Zurupleuropholis gen. nov. (Teleostei,Albian, Argentina), first pleuropholids from the Cretaceous of South America

Although the Cretaceous is characterized by a rich fish diversity, Cretaceous continental fishes from Gondwana are poorly known and comparatively scarce. Among these fishes, the family Pleuropholidae is only known by a few species relatively poorly preserved, from the Middle Jurassic to Lower Cretaceous of Europe, Africa, North America, and South America. In this paper, two new species of the pleuropholid new genus Zurupleuropholis are described, Z. quijadensis gen. et sp. nov. and Z. decollavi gen. et sp. nov. The new fishes were recovered in the Lower Cretaceous lacustrine Lagarcito Formation of central-west Argentina. This taxon constitutes a relevant finding considering that the representation of the family Pleuropholidae is rare worldwide. Zurupleuropholis gen. nov. appears to be the youngest known member of Pleuropholidae, and it represents the second record of the family in South America and the first record in the Cretaceous of the continent.     

Dinosaur burrows in the Otway Group (Albian) of Victoria,Australia, and their relation to Cretaceous polar environments

Three enigmatic structures in an outcrop of the Otway Group (Albian) of Victoria, Australia, compose the first known evidence suggestive of dinosaur burrows outside of North America and the oldest from the fossil record. The most complete of the Otway structures nearly matches the size and morphology of a burrow attributed to the only known burrowing dinosaur, Oryctodromeus cubicularis from the Upper Cretaceous (Cenomanian) of Montana (USA). The suspected burrows cross-cut alluvial facies and overlie nearby strata containing dinosaur tracks. The structures contain identical sand fills in their upper portions, implying a near-synchronous origin and filling; graded bedding in the most complete structure also indicates passive filling of an originally open structure. This probable burrow is a 2.1 m long, gently descending, semi-helical tunnel, with a near-constant diameter (about 30 cm) that connects with an enlarged terminal chamber. The structures are unlikely to have been caused by physical or chemical sedimentary processes, and hence are considered as biogenic structures; moreover, their size and morphology imply tetrapod tracemakers. Burrow allometry indicates tracemakers with a mass of 10–20 kg, matching size estimates for small ornithopods from the Otway Group. Burrowing behavior in hypsilophodontid-grade dinosaurs, which compose most of the dinosaurian assemblage in the Lower Cretaceous of Victoria, was proposed previously as an adaptation for surviving formerly polar conditions in southeastern Australia. This paradigm is explored in detail, particularly through actualistic examples of tetrapod burrowing in cold climates. These structures may provide the first clues of ornithopod burrowing in these extreme environments, while also establishing search images for similar structures in other Lower Cretaceous outcrops in Victoria.     

The upper Cenomanian (Cretaceous) ammonite Neolobites vibrayeanus () in the Middle East: taxonomic and palaeoecologic remarks

In the Middle East and Africa, the Cenomanian ammonite genus Neolobites occurs, partly in great abundance, in shallow marine shelf settings. The genus includes several species but it has remained uncertain to what extent these species reflect biospecies, chronospecies or morphological variants. Based on material from Jordan and Egypt, the morphological variation of Neolobites vibrayeanus is described and discussed. From the several species of Neolobites described in the literature, only N. vibrayeanus, N. fourtaui and N. peroni appear to deserve specific separation. Sedimentological and lithological data, notably the common occurrence in strata that were possibly deposited above storm wave base, suggest that Neolobites was able to inhabit shallow marine settings. In these settings, it seems to form a distinct assemblage with the nautiloid Angulithes. Although N. vibrayeanus shows morphological variability between distinct populations, local N. vibrayeanus assemblages seem to develop morphologically stable populations that show only a little morphological overlap with those of other areas. This may be the reason for the earlier taxonomic splitting. The occurrence in habitats in which other stratigraphically significant ammonites are often missing may be the reason for the previous poor dating of Neolobites assemblages.     

胶莱盆地早白垩世莱阳群沉积物源及地质意义

应用古流向、砾石成分及砂岩碎屑锆石定年方法,综合分析了胶莱盆地早白垩世莱阳群沉积时期的物源组成及其地质意义。古流向,五莲—诸城显示较稳定的N向,莱阳—乳山一带由早期的E-SE向逐渐转变为晚期W-NW向。砾石成分,五莲—诸城—胶州地区以花岗片麻岩、花岗岩、大理岩和石英岩为主,莱阳—乳山早期花岗岩砾石成分含量高,晚期成分复杂。碎屑锆石年龄分布主要集中在110~145 Ma,150~180 Ma,200~250 Ma,600~950 Ma和1700~2600 Ma。由此推断胶莱盆地在早白垩世莱阳群沉积期的物源主要由三部分组成:1盆地南缘苏鲁造山带超高压-高压变质岩和浅变质杂岩;2盆地周缘燕山期(J2-3-K1)花岗岩;3北侧胶北隆起基底(亲华北型)变质岩。并且盆地物源组成表现出明显的区域差异性,这种差异说明当时苏鲁造山带的南、北段在抬升及抬升后可能存在着差异性的隆起和改造,表现为苏鲁造山带南段(南苏鲁造山带)隆升幅度大并且稳定,北段(北苏鲁造山带)表现出较为低缓的隆起或者局部的小隆起并且后期经历大规模的塌陷。另外,物源也指示早白垩世莱阳群沉积时期,胶莱盆地呈现出西高东低的古地貌特征,直到莱阳群沉积晚期,盆地东部才有所抬升。     

Hydrocarbon source rock variability within the Austin Chalk and Eagle Ford Shale (Upper Cretaceous), East Texas, U.S.A.

The Austin Chalk and Eagle Ford Shale are Upper Cretaceous deposits that extend across Texas from the northeast to southwest. These formations contain organic carbon enriched mudstones and chalks that were deposited during transgressions of the Cretaceous epeiric sea in North America. Recent workers in petroleum geochemistry have demonstrated that these organic enriched rocks possessed attributes common to oil source rocks. The present study of these Austin Chalk and Eagle Ford Shale rocks is from the perspective of organic petrology, and it augments the earlier geochemical work that documented source variability within units of these formations. As with the earlier work, the results of this study show that both formations contain intervals that are, when mature, capable of generating commercial quantities of liquid hydrocarbons. However, this work further revealed that Eagle Ford rocks not only exhibit greater or ganic carbon contents, but also have greater quantities of oil-prone kerogen (fluorescent amorphinite and exinite) when compared with rocks from the Austin Chalk. These source rock differences relate to levels or degrees of organic preservation. Dysaerobic to oxic depositional settings seem to be more characteristic of the Austin Chalk than of the Eagle Ford Shale. Such oxic environments do not consistently favor the preservation of organic matter. Usually, well-preserved kerogen forms under more anoxic conditions, such as those that occurred during deposition of some Eagle Ford units. These anoxic conditions suggest that the geographically more extensive Eagle Ford Shale is a more important source for oil than is the Austin Chalk.     

Late Cretaceous stratigraphy,sediments and structure: Gems of the Dorset and East Devon Coast World Heritage Site (Jurassic Coast), England

Extraordinary, long-distance litho-marker beds such as the Lewes and Shoreham Tubular Flints and associated marl seams and fossils, recognised in cliff exposures and cliff-fall boulders, are keys to unlocking the stratigraphy and tectonic structures in the Late Cretaceous of the Dorset and East Devon Coast World Heritage Site (Jurassic Coast). Durdle Cove is a special gem exposing the Lewes and Seaford Chalk stratigraphy where new marker beds are identified and sediments and tectonic structures provide clues to timing of movements that produced a Late Cretaceous pericline which grew into a Miocene monocline along the line of the underlying Purbeck Reverse Fault. During ‘inversion’ along this fault some Late Cretaceous Chalk formations were in part or completely ‘lost’ (e.g. Middle Turonian New Pit Chalk Formation) and others were condensed (e.g. Late Santonian and Early Campanian Newhaven Chalk Formation). Excavation of the A354 road cutting at the Lower Bincombe Farm, has greatly added to the stratigraphical records of Late Cretaceous fossils in South Dorset, especially Coniacian and Early Campanian inoceramid bivalves and the various stratigraphically specific forms of the Late Santonian to Early Campanian echinoid fossil Echinocorys scutata spp. not recorded before in this coastline. The very large bivalve fossil Platyceramus sp. provides clues to chalk sea-floor environments.     

Provenance of quartzarenite clasts in the Tetori Group (Middle Jurassic to Early Cretaceous), Japan: Paleogeographic implications

There are many strata containing quartzite clasts in the Japanese Islands, but the on-land geology of the Japanese Islands has no candidate for the source rocks of the quartzite clasts. This study deals with the provenance of quartzite clasts of the Tetori Group (Middle Jurassic and Early Cretaceous) distributed in northern central Japan. Quartzarenite clasts from conglomerate beds of the Tetori Group are texturally subdivided into three types; the most abundant is matrix-bearing quartzarenite (type 3), followed by poorly sorted feldspar-bearing quartzarenite (type 2) and by well-sorted pure quartzarenite (type 1). To identify the provenance of quartzarenite clasts in the Tetori Group characteristics of quartzarenite sequences distributed in North China and Korea were studied and compared with those of the Tetori quartzarenite clasts. Texturally and geochemically, the quartzarenite clasts of the Tetori Group are very similar to pre-Mesozoic quartzarenites distributed in the south central and east central Korean Peninsula. Considering the previous results of depositional environments, paleomagnetism and paleocurrent studies on the Tetori Group, this study suggests that during deposition of the Tetori Group, the northern part of central Japan was probably land-connected with the central region of eastern Korea.     

Theropod dinosaur diversity and palaeobiology in the Wealden Group (Early Cretaceous) of England: evidence from a previously undescribed tibia

A robust, partial right tibia of a theropod dinosaur (Natural History Museum London collections, BMNH R9385) is described for the first time. The specimen was collected at Hastings, Sussex (England) in the last century, and is among the oldest known of English Wealden Group theropods. It represents a tetanuran theropod that may have been about 3 m in total length, and is distinct from all currently known Wealden theropods for which tibiae have been described. The present specimen is significant palaeobiologically in exhibiting a series of theropod tooth marks on its caudal surface, indicating predation or scavenging by another theropod.     

Possible persistence of the morganucodontans in the Lower Cretaceous Purbeck Limestone Group (Dorset, England)

‘Triconodonts’ are relatively rare in the new Purbeck Limestone Group mammal fauna, especially in comparison with the finds made in the nineteenth century in the same beds. However, besides some remains of the already known Triconodontidae, a new possible morganucodontan of uncertain familial affinities, Purbeckodon batei gen. et sp. nov., has been discovered, extending considerably the chronological range of the order while constituting another testimony to the vitality and diversity of Mesozoic mammals.     

新疆西昆仑加勒万河一带早二叠世菊石化石的发现及岩相古地理意义

在新疆和田县西南峡谷一带的加勒万河谷地区早二叠世地层中首次发现Prostacheoceras cf.Kongaraquense、Artinskia sp.和Agathiceras sp.菊石化石。这3种菊石化石的时代为乌拉尔期,代表了特提斯型菊石组合,与华南的栖霞组相当。其中,Prostacheoceras为特提斯类型的主要属,Artinskia为空谷阶的特征属,Agathiceras则为中石炭世—早二叠世的世界性分布属。此三者同时出现在加勒万河一带加温达坂组中,丰富了加温达坂组的化石资料,对恢复西昆仑地区的古地理和与其他区域生物地层对比提供了重要的化石依据。     

藏西南札达白垩纪Albian期海绿石的矿物学特征及地质意义

海绿石是海相沉积的指相矿物,通常形成于海进系列,与低的沉积物供应速率有关。本文利用岩相和扫描电子显微镜(SEM)对样品进行了详细的观察,并运用X射线粉晶衍射(XRD)、傅立叶变换红外吸收光谱(FTIR)、电子探针微分析(EPMA)等技术,对藏西南札达县波林地区夏拉剖面中的海绿石砂岩和含海绿石灰岩样品进行了系统的分析与研究。上述分析表明砂岩和灰岩中的海绿石均为高演化的海绿石,砂岩中的海绿石为原地海绿石,而灰岩中的海绿石则源于下伏砂岩。通过沉积环境分析和区域地层对比,笔者等认为札达地区砂岩中海绿石的出现可能与Albian晚期印度大陆从澳大利亚—南极大陆的彻底裂解而造成的该地区的海进有关。持续的海进过程导致了该地区高演化的海绿石的形成。     

Early Cretaceous ostracoda from the Goban Spur; D.S.D.P. leg 80, site 549

Site 549 recovered a Lower Cretaceous succession which has been shown to include parts of the Barremian and Albian stages. Forty-four species of Ostracoda are illustrated and their stratigraphic distribution used to recognise three major facies units. An high diversity inner shelf facies earlier in the Barremian gives way to a low diversity, outer shelf facies, higher in the succession. The early Albian appears to indicate a return to an inner shelf fauna. The faunas recovered have been compared to similar faunas elsewhere in N. W. Europe.     

A new hangingfly (Insecta,Mecoptera, Bittacidae) from the Purbeck Limestone Group (Lower Cretaceous) of southern England and a review of Cretaceous Bittacidae

Rapid radiation of the Bittacidae during the Jurassic resulted in high diversity within this family of Mecoptera. More than 40 species within 23 genera have been described from this period. However, around the end of the Jurassic the abundance and diversity of Bittacidae decreased and only seven species in five genera are known to date from the Cretaceous. A new specimen from the basal Cretaceous of England, Tytthobittacus jarzembowski sp. nov., described here, represents the eighth species and the second fossil representative of this family from the European Cretaceous. This hangingfly belongs to an extant and relictual genus previously known only from Australia. The paper also includes a review of all known Cretaceous bittacids and a re-examination of European species Antiquanabittacus nanus Petrulevičius and Jarzembowski, 2004.     

Amazonsaurus maranhensis gen. et sp. nov. (Sauropoda, Diplodocoidea) from the Lower Cretaceous (Aptian–Albian) of Brazil

A new genus and species of an Aptian–Albian sauropod from the Itapecuru Formation, northern Brazil, Amazonsaurus maranhensis, is described. It is known from an incomplete, but diagnostic postcranial skeleton. The new taxon possesses several autapomorphies, such as the anterior caudal vertebrae with lateral laminae formed by the coalescence of the spinoprezygapophyseal and postzygodiapophyseal laminae and, to a lesser extent, of the postzygodiapophyseal laminae. It exhibits many synapomorphies supporting its inclusion in the Diplodocoidea. These include high caudal neural arches and anterior caudal neural arches with spinoprezygapophyseal laminae on the lateral aspect of the neural spine. This record is consistent with previous hypotheses on the existence of a community of Afro-South American dinosaurs.     

The marginal Wealden (non-marine Lower Cretaceous) between Wiltshire and Buckinghamshire,England

Non-marine Lower Cretaceous beds of Wealden aspect have long been known from the northern margin of the Wessex–Weald Basin, between Wiltshire and the south Midlands. Termed the Whitchurch Sands Formation, these badly exposed and generally poorly fossiliferous strata appear to represent interdigitating alluvial and brackish-marine units separated by significant sedimentary breaks. Geological Conservation Review sites within the Whitchurch Sands are described and interpreted for their chronostratigraphic, palaeoenvironmental and palaeoclimatic significance.