scholarly journals An overview of the pterosaur assemblage from the Cambridge Greensand (Cretaceous) of Eastern England

Fossil Record ◽  
2001 ◽  
Vol 4 (1) ◽  
pp. 189-221 ◽  
Author(s):  
D. M. Unwin
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Single Species ◽  
Taxonomic Composition ◽  
Valid Species ◽  
Ecological Differentiation ◽  
Systematic Revision ◽  
Considerable Confusion ◽  
Disjunct Populations ◽  
Early Late

The Cambridge Greensand, a remanié deposit that crops out in Cambridgeshire, eastern England, has yielded numerous, though fragmentary, late Early Cretaceous (Albian) vertebrate fossils including more than 2000 isolated pterosaur bones. So far, 32 species of pterosaur have been proposed in connection with the Cambridge Greensand material, but there has been and continues to be considerable confusion concerning the validity of these taxa, their relationships to each other and to other pterosaurs, and the material upon which they were established. A comprehensive systematic revision identified eleven valid species distributed among three families: the Ornithocheiridae (<i>Ornithocheirus simus</i> and possibly a second, as yet unnamed species of <i>Ornithocheirus, Coloborhynchus capito, Coloborhynchus sedgwickii, Anhanguera cuvieri</i>, and <i>Anhanguera fittoni</i>); the Lonchodectidae (<i>Lonchodectes compressirostris, Lonchodectes machaerorhynchus, Lonchodectes microdon</i> and <i>Lonchodectes platystomus</i>); and a species of edentulous pterosaur (<i>Ornithostoma sedgwicki</i>) that may represent the earliest record for the Pteranodontidae. It is possible that some of the taxa currently recognised represent sexual dimorphs (<i>Coloborhynchus capito</i> and <i>Coloborhynchus sedgwickii, Lonchodectes compressirostris</i> and <i>Lonchodectes machaerorhynchus</i>), or disjunct populations of a single species (<i>Ornithocheirus simus</i> and <i>Ornithocheirus</i> sp., <i>Lonchodectes compressirostris</i> and <i>Lonchodectes microdon</i>) and that there may be as few as seven valid species, but the Cambridge Greensand pterosaurs are too poorly known to demonstrate this at present. The Cambridge Greensand pterosaur assemblage is similar to a slightly younger, but much smaller assemblage from the Lower Chalk of England and shares some elements, such as ornithocheirids, in common with many other late Early and early Late Cretaceous assemblages. It is distinguished by the absence of tapejarids and the presence of <i>Lonchodectes</i> which, so far, is only known from the Cretaceous of England. The disparity in taxonomic composition is possibly related to ecological differentiation, and might also reflect some provincialism in late Early and early Late Cretaceous pterosaur faunas. <br><br> Der Cambridge Greensand, eine in Ostengland aufgeschlossene Remanié-Ablagerung, hat zahlreiche Wirbeltiere aus der oberen Unterkreide (Alb) geliefert. Darunter fanden sich mehr als 2000 isolierte Pterosaurierknochen. Insgesamt wurden aus dem Greensand bis zu 32 Flugsauriertaxa beschrieben, was zu einer beträchtlichen taxonomischen und nomenklatorischen Verwirrung geführt hat, die bis heute andauert. Eine vollständige Revision erkennt 11 Arten aus drei Familien an: (1) die Ornithocheiridae (<i>Ornithocheirus simus</i> und vielleicht eine zweite, bislang unbenannte Art von <i>Ornithocheirus</i>, sowie <i>Coloborhynchus capito, Coloborhynchus sedgwickii, Anhanguera cuvieri</i> und <i>Anhanguera fittoni</i>); (2) die Lonchodectidae (<i>Lonchodectes compressirostris, Lonchodectes machaerorhynchus, Lonchodectes microdon</i> und <i>Lonchodectes platystomus</i>); und schließlich einen zahnlosen Flugsaurier (<i>Ornithostoma sedgwicki</i>). der zu keiner der vorgenannten Familien gehört und sich als stratigraphisch ältester Nachweis der Pteranodontidae erweisen könnte. Es ist nicht auszuschließen, dass einige der gegenwärtig erkannten Taxa eher einen ausgeprägten Sexualdimorphismus illustrieren denn taxonomisch distinkte Arten darstellen (<i>Coloborhynchus capito</i> und <i>Coloborhynchus sedgwickii</i>, <i>Lonchodectes compressirostris</i> und <i>Lonchodectes machaerorhynchus</i>) oder sogar lediglich Endpunkte einer intraspezifisch variablen Population (<i>Ornithocheirus simus</i> und <i>Ornithocheirus</i> sp., <i>Lonchodectes compressirostris</i> und <i>Lonchodectes microdon</i>). In dieser strengeren Fassung bestünden nur sieben gültige Arten, doch leider sind die Flugsaurier des Cambridge Greensand zu schlecht bekannt, um diese Fragen zu beantworten. Die Flugsaurierfauna des Cambridge Greensand ähnelt jüngeren kreidezeitlichen Faunen aus dem Lower Chalk von England. Weiter-hin enthält sie Faunenelemente, wie etwa Ornithocheiriden. die auch für zahlreiche andere Faunen der hohen Unterkreide und tiefen Oberkreide charakteristisch sind. Das Fehlen von Tapejariden und das Auftreten des anscheinend endemischen <i>Lonchodectes</i> sind weitere Kennzeichen des Cambridge Greensand. Die Zusammensetzung der Pterosaurierfaunen folgte offenbar ökologischen Differenzierungen und illustriert einen gewissen Provinzialismus an der Grenze Unter-Oberkreide. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.20010040112" target="_blank">10.1002/mmng.20010040112</a>

scholarly journals New information on the Cretaceous sauropod dinosaurs of Zhejiang Province, China: impact on Laurasian titanosauriform phylogeny and biogeography

2019 ◽  
Vol 6 (8) ◽  
pp. 191057 ◽  
Author(s):  
Philip D. Mannion ◽  
Paul Upchurch ◽  
Xingsheng Jin ◽  
Wenjie Zheng
Keyword(s):  
Southern Hemisphere ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
East Asian ◽  
Zhejiang Province ◽  
Data Matrix ◽  
New Information ◽  
Anatomical Information ◽  
Globally Distributed ◽  
Early Late

Titanosaurs were a globally distributed clade of Cretaceous sauropods. Historically regarded as a primarily Gondwanan radiation, there is a growing number of Eurasian taxa, with several putative titanosaurs contemporaneous with, or even pre-dating, the oldest known Southern Hemisphere remains. The early Late Cretaceous Jinhua Formation, in Zhejiang Province, China, has yielded two putative titanosaurs, Jiangshanosaurus lixianensis and Dongyangosaurus sinensis . Here, we provide a detailed re-description and diagnosis of Jiangshanosaurus , as well as new anatomical information on Dongyangosaurus . Previously, a ‘derived’ titanosaurian placement for Jiangshanosaurus was primarily based on the presence of procoelous anterior caudal centra. We show that this taxon had amphicoelous anterior-middle caudal centra. Its only titanosaurian synapomorphy is that the dorsal margins of the scapula and coracoid are approximately level with one another. Dongyangosaurus can clearly be differentiated from Jiangshanosaurus , and displays features that indicate a closer relationship to the titanosaur radiation. Revised scores for both taxa are incorporated into an expanded phylogenetic data matrix, comprising 124 taxa scored for 548 characters. Under equal weights parsimony, Jiangshanosaurus is recovered as a member of the non-titanosaurian East Asian somphospondylan clade Euhelopodidae, and Dongyangosaurus lies just outside of Titanosauria. However, when extended implied weighting is applied, both taxa are placed within Titanosauria. Most other ‘middle’ Cretaceous East Asian sauropods are probably non-titanosaurian somphospondylans, but at least Xianshanosaurus appears to belong to the titanosaur radiation. Our analyses also recover the Early Cretaceous European sauropod Normanniasaurus genceyi as a ‘derived’ titanosaur, clustering with Gondwanan taxa. These results provide further support for a widespread diversification of titanosaurs by at least the Early Cretaceous.

scholarly journals Phanerozoic Vertical Movements in Morocco

2020 ◽  
Author(s):  
Remi J.G. Charton
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Numerical Models ◽  
Vertical Movements ◽  
The Past ◽  
Basement Rocks ◽  
Exhumation Rates ◽  
Early Late

Our understanding of the Earth’s interior is limited by the access we have of its deep layers, while the knowledge we have of Earth’s evolution is restricted to harvested information from the present state of our planet. We therefore use proxies, physical and numerical models, and observations made on and from the surface of the Earth. The landscape results from a combination of processes operating at the surface and in the subsurface. Thus, if one knows how to read the landscape, one may unfold its geological evolution.In the past decade, numerous studies have documented km-scale upward and downward vertical movements in the continental rifted margins of the Atlantic Ocean and in their hinterlands. These movements, described as exhumation (upward) and subsidence (downward), have been labelled as “unpredicted” and/or “unexpected”. ‘Unpredicted’ because conceptual, physical, and numerical models that we dispose of for the evolution of continental margins do not generally account for these relatively recent observations. ‘Unexpected’ because the km-scale vertical movements occurred when our record of the geological history is insufficient to support them. As yet, the mechanisms responsible for the km-scale vertical movements remain enigmatic.One of the common techniques used by geoscientists to investigate the past kinematics of the continental crust is to couple ‘low-temperature thermochronology’ and ‘time-temperature modelling’. In Morocco alone, over twenty studies were conducted following this approach. The reason behind this abundance of studies and the related enthusiasm of researchers towards Moroccan geology is due to its puzzling landscapes and complex history. In this Thesis, we investigate unconstrained aspects of the km-scale vertical movements that occurred in Morocco and its surroundings (Canary Islands, Algeria, Mali, and Mauritania). The transition area between generally subsiding domains and mostly exhuming domains, yet poorly understood, is discussed via the evolution of a profile, running across the rifted continental margin (chapter 2). Low-temperature thermochronology data from the central Morocco coastal area document a km-scale exhumation between the Permian and the Early/Middle Jurassic. The related erosion fed sediments to the subsiding Mesozoic basin to the northwest. Basement rocks along the transect were subsequently buried between the Late Jurassic and the Early Cretaceous. From late Early/Late Cretaceous onwards, rocks present along the transect were exhumed to their present-day position.The post-Variscan thermal and geological history of the Anti-Atlas belt in central Morocco is constrained with a transect constructed along strike of the belt (chapter 3). The initial episode occurred in the Late Triassic and led to a km-scale exhumation of crustal rocks by the end of the Middle Jurassic. The following phase was characterised by basement subsidence and occurred during the Late Jurassic and most of the Early Cretaceous. The basement rocks were then slowly brought to the surface after experiencing a km-scale exhumation throughout the Late Cretaceous and the Cenozoic. The exhumation episodes extended into the interior of the African tectonic plate, perhaps beyond the sampled belt itself. Exhumation rates and fluxes of material eroded from the hinterlands of the Moroccan rifted margin were quantified from the Permian (chapter 4). The high denudation rates, obtained in central Morocco during the Early to Middle Jurassic and in northern Morocco during the Neogene, are comparable to values typical of rift flank, domal, or structural uplifts. These are obtained in central Morocco during the Early to Middle Jurassic and in northern Morocco during the Neogene. Exhumation rates for other periods in northern to southern Morocco average around ‘normal’ denudation values. Periods of high production of sediments in the investigated source areas are the Permian, the Jurassic, the Early Cretaceous, and the NeogeneThe Phanerozoic evolution of source-to-sink systems in Morocco and surroundings is illustrated in several maps (chapter 5). Substantial shifts in the source areas were evidenced between the central and northern Moroccan domains during the Middle-Late Jurassic and between the Meseta and the Anti-Atlas during the Early-Late Cretaceous. Finally, the mechanisms responsible for the onset and subsistence of the unpredicted km-scale vertical movements are discussed (chapter 6). We propose that a combination of the large-scale crustal folding, mantle-driven dynamic topography, and thermal subsidence, superimposed to changes in climates, sea level and erodibility of the exposed rocks, were crucial to the timing, amplitude, and style of the observed vertical movements.The km-scale vertical movements will continue to be studied for years to come. Expectantly, this Thesis will deliver sufficiently robust grounds for further elaborated and integrated studies in Morocco and beyond.

scholarly journals Early Cretaceous

1982 ◽  
Vol 8 ◽  
pp. 45-49
Author(s):  
Jens Morgen Hansen ◽  
Arne Buch
Keyword(s):  
North Sea ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Late Jurassic ◽  
Significant Feature ◽  
Marine Clay ◽  
The North ◽  
Marine Sand ◽  
The North Sea ◽  
Early Late

The Early Cretaceous sea primarily covered the same basinal regions as the Late Jurassic sea but, late in the Early Cretaceous the sea also covered Late Jurassic land masses. During Early Cretaceous time the topography of the North Sea region became gradually buried. The following major transgression comprises the transition Early/Late Cretaceous. At the Jurassic/ Cretaceous transition, the Late Cimmerian unconformity is a significant feature (fig. 24), known from large parts of the North Sea region. The subsequent transgression and sedimentation of marine clay (the Valhall Formation), and marine sand (the LC-1 Unit), started late in Late Jurassic. Therefore, the formations described in the present chapter also comprise sediments of Late Jurassic age. Thicknesses of the Lower Cretaceous sediments are given in fig. 15.

scholarly journals Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0125786 ◽  
Author(s):  
Lionel Cavin ◽  
Larbi Boudad ◽  
Haiyan Tong ◽  
Emilie Läng ◽  
Jérôme Tabouelle ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Fish Assemblage ◽  
Trophic Structure ◽  
Taxonomic Composition ◽  
Bony Fish ◽  
Early Late

The early evolution of the Tyrannosauridae in Asia

1999 ◽  
Vol 73 (6) ◽  
pp. 1176-1178 ◽  
Author(s):  
M. Manabe
Keyword(s):  
Body Size ◽  
North America ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Early Evolution ◽  
Land Bridge ◽  
Early Late

An isolated premaxillary tooth of a tyrannosaurid from the Lower Cretaceous section of the Tetori Group, Central Honshu, Japan, complements Siamotyrannus, which is based upon an incomplete postcranium for existence of tyrannosaurids in the Early Cretaceous of Asia. The occurrence of a tyrannosaurid tooth in the Japanese early Early Cretaceous further supports the possibility that tyrannosaurids originated during the Early Cretaceous in Asia and migrated to North America when the two continents were connected via a land bridge during the early Late Cretaceous. Thickening of the premaxillary teeth might have predated the increase in body size in tyrannosaurid evolution.

scholarly journals Ecomorphological diversification of squamates in the Cretaceous

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Jorge A. Herrera-Flores ◽  
Thomas L. Stubbs ◽  
Michael J. Benton
Keyword(s):  
Species Richness ◽  
Functional Morphology ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Late Jurassic ◽  
Terrestrial Ecosystems ◽  
Size Disparity ◽  
Pollinating Insects ◽  
Cretaceous Terrestrial Revolution ◽  
Early Late

Squamates (lizards and snakes) are highly successful modern vertebrates, with over 10 000 species. Squamates have a long history, dating back to at least 240 million years ago (Ma), and showing increasing species richness in the Late Cretaceous (84 Ma) and Early Palaeogene (66–55 Ma). We confirm that the major expansion of dietary functional morphology happened before these diversifications, in the mid-Cretaceous, 110–90 Ma. Until that time, squamates had relatively uniform tooth types, which then diversified substantially and ecomorphospace expanded to modern levels. This coincides with the Cretaceous Terrestrial Revolution, when angiosperms began to take over terrestrial ecosystems, providing new roles for plant-eating and pollinating insects, which were, in turn, new sources of food for herbivorous and insectivorous squamates. There was also an early Late Cretaceous (95–90 Ma) rise in jaw size disparity, driven by the diversification of marine squamates, particularly early mosasaurs. These events established modern levels of squamate feeding ecomorphology before the major steps in species diversification, confirming decoupling of diversity and disparity. In fact, squamate feeding ecomorphospace had been partially explored in the Late Jurassic and Early Cretaceous, and jaw innovation in Late Cretaceous squamates involved expansions at the extremes of morphospace.

Earliest occurrence of the Pteranodontidae (Archosauria: Pterosauria) in North America: new material from the Austin Group of Texas

2010 ◽  
Vol 84 (6) ◽  
pp. 1071-1081 ◽  
Author(s):  
Timothy S. Myers
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Taxonomic Diversity ◽  
Left Wing ◽  
North Texas ◽  
Diagnostic Features ◽  
Eagle Ford ◽  
New Material ◽  
Early Late

Remains of a pteranodontid pterosaur are recorded in the basal Austin Group of North Texas. The specimen described here comprises a partial left wing and strongly resemblesPteranodonalthough diagnostic features of that genus are lacking. With an estimated early Coniacian age, this specimen represents the earliest occurrence of the Pteranodontidae in North America and the second earliest occurrence worldwide, predated only byOrnithostomafrom the Cambridge Greensand of England. Pterosaur material recovered from the Eagle Ford and Austin groups of Texas records an early Late Cretaceous change in the composition of North American pterosaur communities between the late Cenomanian and the early Coniacian. This faunal transition appears to be primarily a decrease in morphological disparity rather than a significant reduction in taxonomic diversity. However, the lack of Early CretaceousLagerstättenin North America may produce underestimates of true pterosaur richness during this interval, thereby obscuring a subsequent drop in diversity.

Systematic revision of Sarcosuchus hartti (Crocodyliformes) from the Recôncavo Basin (Early Cretaceous) of Bahia, north-eastern Brazil

2019 ◽  
Author(s):  
Rafael G Souza ◽  
Rodrigo G Figueiredo ◽  
Sérgio A K Azevedo ◽  
Douglas Riff ◽  
Alexander W A Kellner
Keyword(s):  
Phylogenetic Analysis ◽  
Early Cretaceous ◽  
Coastal Areas ◽  
The State ◽  
Evolutionary Origin ◽  
Valid Species ◽  
Top Predator ◽  
Systematic Revision ◽  
Eastern Brazil ◽  
North Eastern

AbstractSarcosuchus hartii was a top predator that inhabited the fluvial and coastal areas of north-eastern Brazil during the Early Cretaceous. Several fossil remains were recovered during the late 19th and early 20th centuries from strata that outcrop in the Recôncavo Basin in the state of Bahia. A re-analysis of this material shows that S. hartii is a valid species. The Brazilian taxon differs from the African Sarcosuchus imperator in the unique pattern of anastomosing ornamentation observed on the enamel surface. The inclusion of S. hartii in a novel phylogenetic analysis recovered it inside Tethysuchia, a large clade comprising South and North American pholidosaurids along Elosuchidae and Dyrosauridae. The evolutionary origin of Sarcosuchus is likely related to a cladogenesis event that resulted from the break-up of Gondwana.

Ginkgophytes of the Ul’ya flora (the Ul’ya depresiion, the Okhotsk-Chukotka volcanogenic belt)

Palaeobotany ◽  
2016 ◽  
Vol 7 ◽  
pp. 80-95 ◽  
Author(s):  
L. B. Golovneva
Keyword(s):  
New Species ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Middle Part ◽  
Leaf Length ◽  
Volcanogenic Belt ◽  
Short Shoots ◽  
Volcanogenic Deposits

The Ul’ya flora comes from the Coniacian volcanogenic deposits of the Amka Formation (the Ul'ya depression, southern part of the Okhotsk-Chukotka volcanogenic belt). Ginkgoaleans are diverse in this flora and represented by three genera: Ginkgo, Sphenobaiera and Baiera. All specimens have no cuticle and were assigned to morphotaxa. Genus Ginkgo includes two species: G. ex gr. adiantoides (Ung.) Heer with entire leaves and G. ex gr. sibirica Heer with dissected leaves. Genus Sphenobaiera also consists of two species: S. ex gr. longifolia (Pom.) Florin with 4–8 leaf lobes and S. ex gr. biloba Prynada with two leaf lobes. Genus Baiera is represented by new species B. lebedevii Golovn., sp. nov.Leaves of this species are 25–30 cm long and 13–16 cm wide, narrowly wedge-shaped with flat slender petiole, dichotomously dissected 4–5 times into linear segments 3–6 mm wide with 6–12 veins. The length of ultimate segments is equal to about a half of leaf length. Leaves attached spirally to ovoid short shoots about 2 cm long. Among the Late Cretaceous floras similar diversity of ginkgoaleans was recorded only in the Turonian-Coniacian Arman flora from middle part of the Okhotsk-Chukotka volcanogenic belt (Herman et al., 2016). Four species of ginkgoaleans from the Ul’ya flora (except G. ex gr. adiantoides) are considered as the Early Cretaceous relicts.

scholarly journals Burial and Exhumation History of the Lujing Uranium Ore Field, Zhuguangshan Complex, South China: Evidence from Low-Temperature Thermochronology

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 116
Author(s):  
Yue Sun ◽  
Barry P. Kohn ◽  
Samuel C. Boone ◽  
Dongsheng Wang ◽  
Kaixing Wang
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
South China ◽  
Thermal History ◽  
Fission Track ◽  
Thermal Evolution ◽  
Negative Relationship ◽  
The Tibetan Plateau ◽  
Uranium Ore ◽  
Production Area

The Zhuguangshan complex hosts the main uranium production area in South China. We report (U-Th)/He and fission track thermochronological data from Triassic–Jurassic mineralized and non-mineralized granites and overlying Cambrian and Cretaceous sandstone units from the Lujing uranium ore field (LUOF) to constrain the upper crustal tectono-thermal evolution of the central Zhuguangshan complex. Two Cambrian sandstones yield reproducible zircon (U-Th)/He (ZHe) ages of 133–106 Ma and low effective uranium (eU) content (270–776 ppm). One Upper Cretaceous sandstone and seven Mesozoic granites are characterized by significant variability in ZHe ages (154–83 Ma and 167–36 Ma, respectively), which show a negative relationship with eU content (244–1098 ppm and 402–4615 ppm), suggesting that the observed age dispersion can be attributed to the effect of radiation damage accumulation on 4He diffusion. Correspondence between ZHe ages from sandstones and granites indicates that surrounding sedimentary rocks and igneous intrusions supplied sediment to the Cretaceous–Paleogene Fengzhou Basin lying adjacent to the LUOF. The concordance of apatite fission track (AFT) central ages (61–54 Ma) and unimodal distributions of confined track lengths of five samples from different rock units suggest that both sandstone and granite samples experienced a similar cooling history throughout the entire apatite partial annealing zone (~110–60 °C). Apatite (U-Th-Sm)/He (AHe) ages from six non-mineralized samples range from 67 to 19 Ma, with no apparent correlation to eU content (2–78 ppm). Thermal history modeling of data suggests that the LUOF experienced relatively rapid Early Cretaceous cooling. In most samples, this was followed by the latest Early Cretaceous–Late Cretaceous reheating and subsequent latest Late Cretaceous–Recent cooling to surface temperatures. This history is considered as a response to the transmission of far-field stresses, involving alternating periods of regional compression and extension, related to paleo-Pacific plate subduction and subsequent rollback followed by Late Paleogene–Recent India–Asia collision and associated uplift and eastward extrusion of the Tibetan Plateau. Thermal history models are consistent with the Fengzhou Basin having been significantly more extensive in the Late Cretaceous–Early Paleogene, covering much of the LUOF. Uranium ore bodies which may have formed prior to the Late Cretaceous may have been eroded by as much as ~1.2 to 4.8 km during the latest Late Cretaceous–Recent denudation.

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