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1.
Three vertebrae discovered in the Barton Clay of Hampshire are described and assigned to two archaeocete whales: the short-bodied dolphin-like Zygorhiza and the large serpentine Basilosaurus. This is the first record of the latter genus outside North America.  相似文献   

2.
The first partial skeleton of a stegosaurian dinosaur was discovered in a brick pit in Swindon, UK in 1874. Since then, numerous stegosaurian remains have been discovered from Europe, North America, Africa and Asia, and continue to be discovered regularly. Stegosaurs are known from the Middle Jurassic to the Early Cretaceous; no definitive evidence of the clade is known from younger deposits. New discoveries are improving our understanding of stegosaur biology and showing that stegosaurs were more morphologically diverse than was previously realized. A new phylogeny, which includes all valid stegosaurian taxa, largely agrees with previous studies and shows the European Dacentrurinae was sister taxon to Stegosaurus. Poor resolution at the base of Stegosauria is probably due to the fragmentary nature of many of the Chinese taxa.  相似文献   

3.
Sites yielding Pennsylvanian (late Carboniferous) coal floras are well known across Europe and North America, but they usually only yield drifted remains of the plants. To understand the ecology of these ancient tropical wetlands properly it is essential that we study in situ remains of the plants. During recent re‐development work of a disused steelworks in the Denbigh Coalfield (north Wales) the remains of a stand of mainly arborescent club mosses and horsetails have been discovered, which is providing new insights into how these unusual plants grew.  相似文献   

4.
From a newly discovered Early Cretaceous fossil site at the Sanlianhe Coal Mine in Tahe County, Heilongjiang Province, the most northern area in China, two freshwater fossil fish had been recovered. This paper reports their classifications and implications regarding the palaeobiogeography of the Jehol Biota. The fish assemblage consists of Yanosteus sp. (Acipenseriforms) and Sinamia sp. (Amiiformes). Both are important members of the well known Jehol Biota, and their occurrence supports the correlation of the Yiliekede Formation at Sanlianhe Coal Mine site with the Jiufotang Formation of West Liaoning. The remains of the Yanosteus sp. from this locality is the first known record of the genus other than in the Yan‐Liao area of China, and the specimens of Sinamia sp. is quite similar to what may be a new species of Sinamia from West Liaoning. The new fossil site represents the most northern site that is undoubtedly part of the extent of the Jehol Biota as currently understood. The northern Great Xing'an Range area is an important region that may link correlations between the Early Cretaceous continental biotas of China, Mongolia and Russia. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

5.
The Eocene Farim‐Saliquinhé phosphate mineralization (FSPM) is a buried sedimentary deposit located in the northern part of Guinea‐Bissau, discovered and spatially constrained during the 1980s by the French Geological Survey (BRGM). In the present work some of the data collected at that time are reworked in the framework of the development of a 3D geological and geochemical model of this mineralization. We show the usefulness of two classical multivariate statistical methods – principal component analysis (PCA) and cluster analysis (CA) – applied to eight geochemical variables (P2O5, SiO2, Al2O3, Fe2O3, CaO, MgO, F and CO2) measured in 247 samples from phosphate facies, for differentiation of samples taken from the different phosphate facies recognized in the FSPM, namely the main ore FPA (30 to 35% high grade phosphate), the calcareous low grade phosphate FPB (10 to 20% P2O5) (both Lutetian), and a mineralized Upper Eocene to Lower Oligocene cover (mainly including the FPO level and a silico‐aluminous phosphate bed), overlying the FPA, which can also be considered a third set of phosphate facies associated with the FSPM.  相似文献   

6.
Jadeite‐bearing kyanite eclogite has been discovered in the Iratsu body of the Sanbagawa belt, SW Japan. The jadeite + kyanite assemblage is stable at higher pressure–temperature (P–T) conditions or lower H2O activity [a(H2O)] than paragonite, although paragonite‐bearing eclogite is common in the Sanbagawa belt. The newly discovered eclogite is a massive metagabbro with the peak‐P assemblage garnet + omphacite + jadeite + kyanite + phengite + quartz + rutile. Impure jadeite is exclusively present as inclusions in garnet. The compositional gap between the coexisting omphacite (P2/n) and impure jadeite (C2/c) suggests relatively low metamorphic temperatures of 510–620 °C. Multi‐equilibrium thermobarometry for the assemblage garnet + omphacite + kyanite + phengite + quartz gives peak‐P conditions of ~2.5 GPa, 570 °C. Crystallization of jadeite in the metagabbro is attributed to Na‐ and Al‐rich effective bulk composition due to the persistence of relict Ca‐rich clinopyroxene at the peak‐P stage. By subtracting relict clinopyroxene from the whole‐rock composition, pseudosection modelling satisfactorily reproduces the observed jadeite‐bearing assemblage and mineral compositions at ~2.4–2.5 GPa, 570–610 °C and a(H2O) >0.6. The relatively high pressure conditions derived from the jadeite‐bearing kyanite eclogite are further supported by high residual pressures of quartz inclusions in garnet. The maximum depth of exhumation in the Sanbagawa belt (~80 km) suggests decoupling of the slab–mantle wedge interface at this depth.  相似文献   

7.
Coniacian rudist-buildups have been discovered in the Dernaïa-Tamesmida area (west central Tunisia). They are sedimentologically studied in detail in this paper. Reefs sensu stricto are made up of rudists (Hippuritidae and Radiolitidae) and they show a height:lateral extension ratio of about 1:50. The fore-reef is composed of southwest progradang pelletoid sandwaves, whilst hemipelagic micrite has been deposited in the distal talus. The back-reef lagoons (NE side) include green algae and annelid, miliolid, ostracod and gastropod biotopes. Perilagoonal oolitic bars may border these environments.These reefs evolved in a shallow, relatively open environment. They correspond to barrier-reef complexes which developed at the margin of a generally shallow carbonate ramp.In terms of the sequence stratigraphy, they characterise late low sea levels and especially the high sea levels of the uppermost Turonien-Coniacian depositional sequence.  相似文献   

8.
The remains of trilobites and other species were unexpectedly discovered in a volcanic ash layer beneath the Permian–Triassic Boundary (PTB). Based on a biostratigraphic investigation of the Zhongliangshan section in Chongqing, South China, the quantity of the species gradually decreased with subsequent volcanism. This finding provides an opportunity to further understand the disappearance of trilobites and the evolution of the mass extinction event. The temporal coincidence between the volcanic eruption event and the loss of trilobites and other species supports the idea of a cause-and-effect relationship. The species remains in the ash bed appeared before the disappearance of Clarkina yini and the climax of the negative carbon isotope excursion, which implies that the onset of the mass extinction occurred at the end-Permian. The explosive volcanic events caused massive releases of CO2, toxic gases and volcanic ash and resulted in loss of habitat for certain species in the Tethys domain. This phenomenon may have led to the abrupt death of trilobites and the catastrophic collapse of biodiversity.  相似文献   

9.
Although body fossils of shorebirds and shorebird-like species are extremely rare from the Cretaceous, rapid increase in the discovery of bird footprint sites provides valuable alternate evidence to help fill gaps in the story of the early evolution of shorebird-like species. Newly discovered bird tracks from the Albian-Cenomanian Dakota Formation in northeastern Utah represent the first report of the ichnogenus Koreanaornis from North America and only the second report of bird tracks from this formation. These tracks are not attributable to Aquatilavipes as previously claimed. Three well-preserved trackways are described and provisionally referred to Koreanaornis cf. hamanensis (Kim). However, a review of the ichnotaxonomy of shorebird ichnites reveals that this ichnotaxon also closely resembles the Miocene ichnospecies Avipeda sirin (Vyalov). This latter comparison points to the need for a thorough evaluation of the similarity between Mesozoic and Cenozoic avian ichnotaxa, which may be over-split in some cases and under-differentiated in others.The new material helps distinguish ichnogenus Koreanaornis from the larger bird track Aquatilavipes, which is more abundant and widespread in North America. In some cases Aquatilavipes has been incorrectly used as a catch-all ichnogenus both in North America and Asia. The Dakota Formation stratigraphy at the tracksite indicates that the track makers lived in a marginal marine paleoenvironment. However, despite the widespread distribution of such facies, often replete with dinosaur tracks, the bird track record of the Dakota Formation, and the Cretaceous of the western USA remains relatively sparse in comparison with other areas such as east Asia.  相似文献   

10.
An assemblage of Early Ordovician dichograptids has been discovered in a spotted slate from the Omeo Metamorphic Complex just north of Eskdale in northeast Victoria. Identifiable species present are Tetragraptus fruticosus (4 br.), T. acclinans, and Didymograptus cf. D. ensjoensis. Together these indicate an age corresponding to zone Bel of the early Bendigonian. They are therefore the first recorded fossils of pre‐Darriwilian age discovered east of the Howqua Zone in Victoria. The depositional history of the Wagga Trough is thus demonstrated to have commenced at least early in the Ordovician, rather than in the late Middle Ordovician as previously thought.  相似文献   

11.
The Late Cretaceous (Santonian) continental vertebrate locality of Iharkút, western Hungary has provided numerous azhdarchid pterosaur remains including the recently described, Bakonydraco galaczi. Since the first report of these fossils, additional remains have been discovered that improve considerably our knowledge of some aspects of the anatomy of azhdarchid pterosaurs. New cranial material described here indicates an edentulous, non-crested premaxillary rostrum in Bakonydraco similar to that of Quetzalcoatlus and reveals that this rostrum was considerably thinner and more lightly built than the relatively massive, pointed mandibular symphysis. In addition, the contact surface of the upper and lower jaws of Bakonydraco at least in the symphyseal region was more similar to Tapejara wellnhoferi than to other azdarchids: the contact is irregular and the premaxilla does not fit closely the rostral part of the mandible. Among the postcranial material the atlas-axis complex possessing lateral pneumatic foramina is of great importance because it further supports the notion of interspecific variability of vertebral pneumaticity among pterosaurs.  相似文献   

12.
This paper presents the results of pollen and charcoal analyses carried out in the sedimentary formation of Ponta da Passadeira, south of the Tejo River estuary, Portugal. The data provide information regarding the evolution of the coastline and ecosystem of the estuary during the mid and late Holocene. The study focuses on a group of upright woody fossilized tree remains that, together with those identified earlier by García‐Amorena et al. (2007), form part of the fossil forest of Ponta da Passadeira. Eight remains were identified as Pinus pinaster, four as Pinus pinea and one as Pinus sp. Two specimens of these species were dated to 6523 and 5805 cal. a BP. Pollen analysis was undertaken in a clay layer located at the same point as the fossil forest, which is currently below sea level; the base of the clay layer was dated to 4906 cal. a BP. The pollen spectra reflect the dynamics of the vegetation that grew on this deposit, whereas the sporopollinic input masks the contribution of the regional vegetation. Wood charcoal remains recovered at an adjacent Final Neolithic settlement were also analysed, and a Pinus sp. specimen was radiocarbon dated to 5050 cal. a BP. The correlation amongst the three records provides key ecological markers for the understanding of the evolution of coastline ecosystems, and helps to clarify and understand the Holocene sea rise on the Atlantic seaboard of Iberia. The geographical location of Ponta da Passadeira is strategic because it enables a more clear definition of the configuration of landscapes that show an inflection point in this area of central Portugal.  相似文献   

13.
This paper presents the study and palaeoecological analysis of fossil fish vertebrae of the Arbreda Cave (Serinyà, Girona), probably the most significant Catalan palaeolithic site. Morphological and radiographical studies were used to identify vertebrae to genus and, whenever possible, to species level. The taxa identified are: Anguilla anguilla, Barbussp., Leuciscussp., Rutilus sp., Salmo salar, Salmo trutta and Salmo sp. Species distribution at various archaeological levels provided palaeoecological data. There is a high proportion of Salmo trutta remains in the Upper Gravettian level and a sudden decrease of fossil fish bones in the Solutrean level with shouldered points. This decrease coincides with the period of lower temperatures of the Late Pleniglacial. Finally, the post-glacial terra rossa level is characterised by the absence of Salmo trutta remains. The presence of Salmo salar in Mediterranean sites has often been discussed. However, the dating of remains of this Atlantic species found in the Arbreda Cave makes it likely that these specimens were caught in Atlantic rivers on the northern Pyrennean slope and then transported to the area studied. © 1997 John Wiley and Sons, Ltd.  相似文献   

14.
The Daposhang section at Muhua, Changshun. Guizhou. is an excellent and attractive DevonianCarboniferous boundary section. The transitional beds between the Devonian and Carboniferous of the sectionare continuous and well exposed. belonging to the deep-water basin facies Abundant fossil groups have beendiscovered from this section: conodonts. ammonoids. trilobites. ostracods. vertebrate microfossils and so on.So far as known. it has the most continuous and complete conodont zonation for the Devonian-Carboniferousboundary beds in the world. It is especially worth pointing out that both typical Siponodella pracsulcata andthe transitional forms between S. praesulcata and S. sulcata have been found from the upper pracsulcata Zoneof the Daposhang section. Evidently. we can not only prove the actual existence of the evolutionary lineagefrom S. praesulcata to S. sulcata, but also exactly define the level of the Devonian-Carboniferous boundary. Inthis paper. the development of the Devonian-Carboniferous boundary beds at the Daposhang section is dealtwith and the section is compared with the Muhua section and the Nanbiancun section which are the candidatesfor the Devonian-Carboniferous boundary stratotype. In the authous opinion the Daposhang section is obvi-ously better than the Muhua and the Nanbiancun sections. hence it can be recommended as one of the candi-dates for the international Devonian-Carboniferous boundary stratotype.  相似文献   

15.
A deep‐water trilobite fauna has been discovered in the otherwise graptolitic Mydrim Formation near Clarbeston Road, Pembrokeshire, south‐west Wales. Associated graptolites indicate an early Caradocian age. The trilobites comprise three species with eyes reduced or absent, representing an atheloptic assemblage with benthic life habits, which appeared during a short period of relative oxygenation of the Welsh Basin. The trilobite Platycalymene dilatata (Tullberg) is redescribed from the type material from Sweden, and new material from Wales is assigned to this species. Two new species are described in addition. Rorringtonia multisegmentata sp. nov. possesses twelve thoracic segments, which has implications for the classification of the Rorringtoniidae within the Aulacopleuroidea. Trinucleus conollyi sp. nov. differs from T. fimbriatus in the proliferation of the radial sulci. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

16.
We carried out a systematic investigation on the pollen content of sediment adhering to skeletal elements of large mammals which originate from the long lacustrine record of Leffe (Early Pleistocene of the Italian Alps). Three local faunas were discovered during mining activities along the intermediate part (spanning from 1.5 to 0.95 Ma) of the basin succession. The excellent pollen preservation allowed testing the reproducibility of the pollen signal from single skeletons. A clear palaeoenvironmental patterning, consistent with the ecological preferences of the considered mammal species, emerged from the canonical correspondence analysis of pollen types diagnostic for vegetation communities. Edaphic factors related to seasonal river activity changes and to the development of swamp forests in the riverbanks are significantly associated to the occurrences of Hippopotamus cf. antiquus, whereas finds of Mammuthus meridionalis belong to fully forested landscapes dominated by conifer or mixed forests of oceanic, warm to cool-temperate climate. Rhinoceros habitats include variable forest cover under different climate states. Distinct cool-temperate, partially open vegetation could be recognized for large deer included Cervalces cf carnutorum.A palynostratigraphic correlation between individual spectra and a reference palynostratigraphic record allowed assignment of many fossil remains to a precise stratigraphic position. This procedure also shown that the Leffe local faunas include specimens accumulated under different environmental and climate states, as a consequence of high-frequency climate changes characterizing the Late Villafranchian Early Pleistocene.  相似文献   

17.
An accumulation of mammoth hair, discovered in the Bol'shaya Chukochya River valley (northeast Yakutia, Russia), was found to contain remains of terrestrial and aquatic organisms, including plants, insects, crustaceans, birds and mammals. Radiocarbon dating indicated that this post‐mortem taphocoenosis represented multiple time periods. The mammoth hair was dated to older than 45 ka BP, the plants were dated to 12 750±50 a BP (which corresponds to a shift in the environmental conditions and landscapes during the formation of thermokarst in northeastern Russia) and the bird feathers were dated to 4115±40 a BP. A scenario of the formation of this fossil assemblage is proposed, covering the MIS 3‐1 time range. The hair also yielded various Arctic branchiopod crustaceans, which inhabit shallow temporary water bodies and therefore are important for reconstruction of palaeoenvironments. The cladoceran subgenus Daphnia (Ctenodaphnia), currently absent from the Asian part of Beringia, is reported from this region for the first time. The study demonstrates that the discovered permafrost‐preserved hair is a unique repository of Ice Age organisms.  相似文献   

18.
Remains of the cercopithecid Mesopithecus monspessulanus are relatively rare. Two previously unpublished mandibles of M. monspessulanus (housed in the Basel Naturhistorisches Museum), from the Italian locality of Villafranca d’Asti are described. These remains belong to the assemblage of the Triversa Faunal Unit, dated to the Early Villafranchian, that is to the unit MN16a (Middle Pliocene) of the European mammal biochronology. According to this recently revised biochronological attribution, Villafranca d’Asti records the last Mesopithecus occurrence in Europe. The NOW (Neogene Old World) database has been used as a basis to evaluate both the mammalian faunal and the palaeoenvironmental context at the time surrounding this last occurrence of Mesopithecus. The comparison (taxonomical composition and ungulate hypsodonty), between the Villafranca d’Asti assemblage and other Plio-Pleistocene mammal communities of Europe, shows that the extinction of Mesopithecus is related to a faunal turnover and a change toward more open landscapes during the Early–Middle Villafranchian transition. This is consistent with the “Elephant-Equus event”, that occurred in Europe at 2.5 Ma. Furthermore, the co-occurring but more terrestrial cercopithecid Macaca crossed this faunal turnover. This strengthens the assumption that the latest Mesopithecus species, M. monspessulanus, had woodland-oriented adaptations. Editorial handling: J.-P. Billon-Bruyat & M. Chiari (Guest)  相似文献   

19.
Some conodonts described by Tea Kolar-Jurkovsek and Bogdan Jurkovsek (2007) from the Permian-Triassic boundary section in the ?iri area of western Slovenia are revised in this paper. One specimen that they assigned to Hindeodus parvus is tentatively regarded as Hindeodus cf. scalaris Wu 2005. Two specimens that they assigned to Isarcicella sp. A is changed to Hindeodus parvus. One specimen that they described as Isarcicella lobata Perri and Farabegoli is changed to Hindeodus crenatus Wu (2006). One specimen that they assigned to Isarcicella turgida (Kozur, Mostler and Rahimi-Yazd) is changed to Hindeodus cf. parvus. Since these revisions, the three conodont zones that they defined have been correspondingly revised. Their first zone may belong to Hindeodus parvus zone, but it is not certain. Their second zone is changed to the Hindeodus parvus zone, and their third one remains as is.  相似文献   

20.
This paper gives a brief report on the latest results in litho-, bio-, and chrono-stratigraphy obtained fromthe authors' further research on the Meishucun section during 1987-1988. More attention was paid to the studyof the microtexture of Lapworthella and some new materials of trace fossils. Phycodes pendum Seilacher, animportant index for correlation, was also discovered in the Zhongyicun Member. In the Yu' anshan Membermany worms, medusas and arthropods of the Chengjiang fauna have been found by other workers. Asupplemental study was made on the fossil zones of the Meishucunian stage. Based on new isotopic data, theage of the Precambrian-Cambrian boundary should now be 597 Ma. It is further suggested that point "B" re-mains as an optimum selection for defining the Precambrian-Cambrian boundary.  相似文献   

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