scholarly journals Late Jurassic foraminifera from the southern Waschberg-Ždánice Unit (Klentnice beds, Lower Austria)

2020 ◽  
Vol 113 (1-2) ◽  
pp. 155-167
Author(s):  
Holger Gebhardt
Keyword(s):  
Late Jurassic ◽  
Upper Jurassic ◽  
Deposit Feeders ◽  
Common Genus ◽  
Different Sources ◽  
Early Late ◽  
High Diversity

AbstractForaminiferal assemblages from Upper Jurassic Klentnice beds in Lower Austria are described and analysed. The early late Tithonian assemblages comprise 75 foraminiferal taxa and simple diversities reach up to 31 taxa per sample, pointing to comparatively high diversity in general. The assemblages are dominated by lenticulinid forms (Genera Astacolus, Lenticulina, Saracenaria, Vaginulinopsis). Trocholina is the most common genus and present in all samples. Other frequent genera are Marssonella and Neobulimina. Co-occurrence of epifaunal (grazing) herbivores and epi- to deep infaunal active deposit feeders points to mixed assemblages from different sources and supports the concept of turbiditic systems as prevailing sedimentary regimes in the basinal setting.

scholarly journals An Upper Jurassic ichthyosaur (Ichthyosauria: Ophthalmosauridae) from the Bowser Basin, British Columbia

2016 ◽  
Vol 53 (1) ◽  
pp. 34-40
Author(s):  
Robin L. Sissons ◽  
Michael W. Caldwell ◽  
Carol A. Evenchick ◽  
Donald B. Brinkman ◽  
Matthew J. Vavrek
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Late Jurassic ◽  
Body Shape ◽  
Depositional Environment ◽  
Upper Jurassic ◽  
Generic Level ◽  
Shallow Marine ◽  
Northwestern North America ◽  
High Diversity

Although the Jurassic was a period of high diversity in ichthyosaurs, only a small number of specimens have been recorded from Canada to date. We describe here a new occurrence of an ophthalmosaurid ichthyosaur from a shallow marine depositional environment within the Bowser Basin of northern British Columbia. Based on vertebral diameters and the size of the humerus, the ichthyosaur was relatively large compared to other contemporaneous forms, yet possessed teeth that were small for its body size. As well, the height to length ratio of the preserved vertebrae suggests it may have had a more elongate, less regionalized body shape. Although indeterminate at a generic level, the presence of Late Jurassic ichthyosaurs in nearshore waters of northwestern North America further demonstrates their cosmopolitan distribution.

The first ophthalmosaurid ichthyosaur from the Upper Jurassic of the Umbrian–Marchean Apennines (Marche, Central Italy)

2016 ◽  
Vol 154 (4) ◽  
pp. 837-858 ◽  
Author(s):  
ILARIA PAPARELLA ◽  
ERIN E. MAXWELL ◽  
ANGELO CIPRIANI ◽  
SCILLA RONCACÈ ◽  
MICHAEL W. CALDWELL
Keyword(s):  
Late Jurassic ◽  
Phylogenetic Analyses ◽  
Central Italy ◽  
Upper Jurassic ◽  
New Taxon ◽  
Western Tethys ◽  
Shark Teeth ◽  
Local Endemic ◽  
First Time ◽  
Early Late

AbstractThe first ophthalmosaurid ichthyosaur from the Upper Jurassic deposits of the Central–Northern Apennines (Marche, Italy) is here described for the first time. The specimen is relatively complete and is referred to Gengasaurus nicosiai gen. et sp. nov. based on a unique combination of characters, including a peculiar condition of the preaxial accessory facet on the humerus. The faunal association of the ichthyosaur-bearing level indicates a late Kimmeridgian – earliest Tithonian age, and its finding contributes significantly to our knowledge of the diversity of Late Jurassic ichthyosaurs from the Western Tethys. Two shark teeth assigned to the order Hexanchiformes were also recovered in association with the ichthyosaur specimen, suggesting that scavenging of the carcass might have occurred. Gengasaurus can be referred to Ophthalmosauridae based on the reduced extracondylar area of the basioccipital, and the presence of a preaxial digit. It differs from Ophthalmosaurus spp. in several respects, including the shape of the posterior basisphenoid, the shape of the supraoccipital, the anteriorly deflected preaxial facet of the humerus, and a proximodistally shortened ulna. The new taxon actually shares diagnostic characters with both members of the two main lineages recovered in previous phylogenetic analyses, more nested within Ophthalmosauridae. The affinities of Gengasaurus to genera from both the northern and southern hemispheres also suggest that connectivity between pelagic habitats was high during the early Late Jurassic, allowing dispersal of some forms, followed by local, endemic divergence.

scholarly journals Anatomy and systematics of the diplodocoid Amphicoelias altus supports high sauropod dinosaur diversity in the Upper Jurassic Morrison Formation of the USA

2021 ◽  
Vol 8 (6) ◽  
pp. 210377
Author(s):  
Philip D. Mannion ◽  
Emanuel Tschopp ◽  
John A. Whitlock
Keyword(s):  
Late Jurassic ◽  
Phylogenetic Analyses ◽  
Upper Jurassic ◽  
Phylogenetic Position ◽  
Morrison Formation ◽  
Growth Series ◽  
Distinct Genus ◽  
The Usa ◽  
Phylogenetic Signature ◽  
High Diversity

Sauropod dinosaurs were an abundant and diverse component of the Upper Jurassic Morrison Formation of the USA, with 24 currently recognized species. However, some authors consider this high diversity to have been ecologically unviable and the validity of some species has been questioned, with suggestions that they represent growth series (ontogimorphs) of other species. Under this scenario, high sauropod diversity in the Late Jurassic of North America is greatly overestimated. One putative ontogimorph is the enigmatic diplodocoid Amphicoelias altus , which has been suggested to be synonymous with Diplodocus . Given that Amphicoelias was named first, it has priority and thus Diplodocus would become its junior synonym. Here, we provide a detailed re-description of A. altus in which we restrict it to the holotype individual and support its validity, based on three autapomorphies. Constraint analyses demonstrate that its phylogenetic position within Diplodocoidea is labile, but it seems unlikely that Amphicoelias is synonymous with Diplodocus . As such, our re-evaluation also leads us to retain Diplodocus as a distinct genus. There is no evidence to support the view that any of the currently recognized Morrison sauropod species are ontogimorphs. Available data indicate that sauropod anatomy did not dramatically alter once individuals approached maturity. Furthermore, subadult sauropod individuals are not prone to stemward slippage in phylogenetic analyses, casting doubt on the possibility that their taxonomic affinities are substantially misinterpreted. An anatomical feature can have both an ontogenetic and phylogenetic signature, but the former does not outweigh the latter when other characters overwhelmingly support the affinities of a taxon. Many Morrison Formation sauropods were spatio-temporally and/or ecologically separated from one another. Combined with the biases that cloud our reading of the fossil record, we contend that the number of sauropod dinosaur species in the Morrison Formation is currently likely to be underestimated, not overestimated.

scholarly journals The complicated and surprisingly early origin of the pterodactyloid bauplan

2017 ◽  
Author(s):  
David M. Unwin
Keyword(s):  
Phylogenetic Analysis ◽  
Late Jurassic ◽  
Evolutionary History ◽  
Upper Jurassic ◽  
Anatomical Changes ◽  
History Of ◽  
Fifth Toe ◽  
Early Origin ◽  
Early Late ◽  
Complex Evolutionary History

The origin of the pterodactyloid bauplan from that of non-monofenestratan (‘rhamphorhynchoid’) pterosaurs involved extensive anatomical changes and had profound consequences for the evolutionary history of Pterodactyloidea, a clade that dominated the aerial realm throughout the Cretaceous. This important evolutionary transformation, about which almost nothing was known for almost two centuries, is now rapidly coming into focus thanks to a plethora of new pterosaur fossils from the Middle and Upper Jurassic of South America, Europe and China. So far, however, these finds have largely been considered in isolation from each other and few have been thoroughly evaluated. Phylogenetic analysis, combined with improved stratigraphic data for all potentially relevant taxa including putative non-pterodactyloid monofenstratans (NPMs) and the oldest known pterodactyloids (e.g. Liaodactylus) was used to generate a new map of the anatomical transformations and temporal history of the non-monofenestratan–pterodactyloid transition. Evolution of the pterodactyloid skull construction predates the Middle Jurassic, but remains almost completely undocumented by fossils. Liaodactylus reveals that innovation in pterodactyloid skull anatomy and the appearance of derived features was well underway prior to the Upper Jurassic. Douzhanopterus, a derived NPM, demonstrates that elongation of the metacarpus and reduction of the tail and fifth toe (classic pterodactyloid synapomorphies) also predates the Upper Jurassic, but disjunction in the degree of their development across taxa is not consistent with simple explanations such as ‘adaptation for flight’. Overall, late Early to early Late Jurassic pterosaurs were much more diverse and had a far more complex evolutionary history than heretofore recognised.

scholarly journals The complicated and surprisingly early origin of the pterodactyloid bauplan

2017 ◽  
Author(s):  
David M. Unwin
Keyword(s):  
Phylogenetic Analysis ◽  
Late Jurassic ◽  
Evolutionary History ◽  
Upper Jurassic ◽  
Anatomical Changes ◽  
History Of ◽  
Fifth Toe ◽  
Early Origin ◽  
Early Late ◽  
Complex Evolutionary History

The origin of the pterodactyloid bauplan from that of non-monofenestratan (‘rhamphorhynchoid’) pterosaurs involved extensive anatomical changes and had profound consequences for the evolutionary history of Pterodactyloidea, a clade that dominated the aerial realm throughout the Cretaceous. This important evolutionary transformation, about which almost nothing was known for almost two centuries, is now rapidly coming into focus thanks to a plethora of new pterosaur fossils from the Middle and Upper Jurassic of South America, Europe and China. So far, however, these finds have largely been considered in isolation from each other and few have been thoroughly evaluated. Phylogenetic analysis, combined with improved stratigraphic data for all potentially relevant taxa including putative non-pterodactyloid monofenstratans (NPMs) and the oldest known pterodactyloids (e.g. Liaodactylus) was used to generate a new map of the anatomical transformations and temporal history of the non-monofenestratan–pterodactyloid transition. Evolution of the pterodactyloid skull construction predates the Middle Jurassic, but remains almost completely undocumented by fossils. Liaodactylus reveals that innovation in pterodactyloid skull anatomy and the appearance of derived features was well underway prior to the Upper Jurassic. Douzhanopterus, a derived NPM, demonstrates that elongation of the metacarpus and reduction of the tail and fifth toe (classic pterodactyloid synapomorphies) also predates the Upper Jurassic, but disjunction in the degree of their development across taxa is not consistent with simple explanations such as ‘adaptation for flight’. Overall, late Early to early Late Jurassic pterosaurs were much more diverse and had a far more complex evolutionary history than heretofore recognised.

scholarly journals Isolated pliosaurid teeth from the Albian–Cenomanian (Cretaceous) of Annopol, Poland

2017 ◽  
Vol 67 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Daniel Madzia ◽  
Marcin Machalski
Keyword(s):  
Cross Section ◽  
Late Cretaceous ◽  
Type Species ◽  
Late Jurassic ◽  
Morphological Variability ◽  
Original Material ◽  
Tooth Crown ◽  
Similar Morphology ◽  
Faunal Turnover ◽  
Early Late

AbstractBrachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic- Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian-middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.

Radiolarian assemblages of Middle and Late Jurassic to early Late Cretaceous (Cenomanian) ages from an olistolith record pelagic deposition within the Bornova Flysch Zone in western Turkey

2012 ◽  
Vol 183 (4) ◽  
pp. 307-318 ◽  
Author(s):  
Ugur Kagan Tekin ◽  
M. Cemal Göncüoglu ◽  
Seda Uzuncimen
Keyword(s):  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Western Turkey ◽  
Oceanic Basin ◽  
Platform Margin ◽  
Lowermost Part ◽  
Early Late ◽  
Radiolarian Assemblages

Abstract The Bornova Flysch Zone (BFZ) in NW Anatolia comprises several olistoliths or tectonic slivers, representing various parts of the Izmir-Ankara ocean. Radiolarian assemblages extracted from one of the olistoliths of the BFZ, cropping out along the Sögütlü section, to the NE Manisa city, were studied in detail. The lowermost part of the section contains latest Bajocian – early Callovian radiolarian taxa, followed by radiolarian assemblages indicating Late Jurassic to early Late Cretaceous (Cenomanian) ages. Previous studies reveal that the Izmir-Ankara oceanic basin was initially opened during late Ladinian – early Carnian. The new radiolarian data obtained from this olistolith reveals that relatively condensed, and possibly more or less continuous, pelagic sedimentation took place during the late Middle Jurassic to early Late Cretaceous in a non-volcanic oceanic basin closer to the Tauride-Anatolide platform margin.

scholarly journals The taphonomy of dinosaurs from the Upper Jurassic of Tendaguru (Tanzania) based on field sketches of the German tendaguru expedition (1909–1913)

Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 25-61 ◽  
Author(s):  
W.-D. Heinrich
Keyword(s):  
Old Age ◽  
Late Jurassic ◽  
Depositional Environment ◽  
Upper Jurassic ◽  
Skeletal Remains ◽  
Time Span ◽  
Post Mortem ◽  
Seasonal Drought ◽  
Long Time

Tendaguru is one of the most important dinosaur localities in Africa. The Tendaguru Beds have produced a diverse Late Jurassic (Kimmeridgian to Tithonian) dinosaur assemblage, including sauropods (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), theropods (e.g., <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>), and ornithischians (<i>Kentrosaurus, Dryosaurus</i>). Contrary to the well studied skeletal anatomy of the Tendaguru dinosaurs, the available taphonomic information is rather limited, and a generally accepted taphonomic model has not yet been established. Assessment of unpublished excavation sketches by the German Tendaguru expedition (1909–1913) document bone assemblages of sauropod and ornithischian dinosaurs from the Middle Saurian Bed, Upper Saurian Bed, and the Transitional Sands above the <i>Trigonia smeei</i> Bed, and shed some light on the taphonomy of the Tendaguru dinosaurs. Stages of disarticulation range from incomplete skeletons to solitary bones, and strongly argue for carcass decay and post-mortem transport prior to burial. The sauropod bone accumulations are dominated by adult individuals, and juveniles are rare or missing. The occurrence of bones in different superimposed dinosaur-bearing horizons indicates that skeletal remains were accumulated over a long time span during the Late Jurassic, and the majority of the bone accumulations are probably attritional. These accumulations are likely to have resulted from long-term bone imput due to normal mortality events caused by starvation, seasonal drought, disease, old age and weakness. The depositional environment of the Middle and Upper Saurian Bed was mainly limnic to brackish in origin, while the palaeoenvironment of the Transitional Sands was marginal marine. <br><br> Tendaguru zählt zu den bedeutendsten Dinosaurier-Lagerstätten Afrikas. Aus den Tendaguru-Schichten sind zahlreiche Skelettreste von Sauropoden (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), Theropoden (z.B. <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>) und Ornithischiern (<i>Kentrosaurus, Dryosaurus</i>) geborgen worden. Sie stammen aus der späten Jura-Zeit (Kimmeridge — Tithon). Während der Skelettbau der Tendagurusaurier gut untersucht ist, wirft die Taphonomie des Sauriervorkommens von Tendaguru noch immer Fragen auf. Unklar ist bislang, wie die enormen Anreicherungen von Dinosaurierknochen in den Tendaguru-Schichten zustandekamen. Unveröffentlichte Grabungsskizzen der Deutschen Tendaguru Expedition (1909–1913) erweitern unsere Kenntnisse über die Taphonomie der Tendagurusaurier. In den ausgewerteten Grabungsskizzen sind Knochenansammlungen von Sauropoden und Ornithischiern aus dem Mittleren und Oberen Sauriermergel sowie aus den Übergangsschichten über der <i>Trigonia smeei</i>-Schicht dokumentiert. Die Lage und der Erhaltungszustand der Funde lassen auf erheblichen Zerfall der Kadaver und post-mortalen Transport von Skelettelementen vor der Einbettung schließen. Das Vorkommen von Saurierknochen in mehreren übereinanderliegenden Profilabschnitten der Tendaguru-Schichten zeigt, daß Skelettreste während der späten Jura-Zeit über einen längeren Zeitraum hinweg akkumuliert wurden. Die Ansammlungen von Skelettresten gehen wahrscheinlich auf „normale” Sterbe-Ereignisse zurück, wie z. B. Verhungern, Verdursten, Kankheit, Altersschwäche und jahreszeitliche Dürre. Als Ablagerungsraum der Mittleren und Oberen Saurierschicht kommt ein küstennaher limnischer, zeitweise wohl auch brackischer Küstenstreifen in Betracht. Die knochenführenden Übergangsschichten unter- und oberhalb der Saurierschichten sind randlich marine Ablagerungen. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.1999.4860020102" target="_blank">10.1002/mmng.1999.4860020102</a>

scholarly journals Detrital zircon geochronology and provenance of the Middle to Late Jurassic Paradox Basin and Central Colorado trough: Paleogeographic implications for southwestern Laurentia

Geosphere ◽  
2021 ◽  
Author(s):  
John I. Ejembi ◽  
Sally L. Potter-McIntyre ◽  
Glenn R. Sharman ◽  
Tyson M. Smith ◽  
Joel E. Saylor ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Detrital Zircon ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Morrison Formation ◽  
Detrital Zircon Geochronology ◽  
Sediment Dispersal ◽  
Paradox Basin ◽  
Southern Oklahoma ◽  
Trace Elemental

Middle to Upper Jurassic strata in the Paradox Basin and Central Colorado trough (CCT; south­western United States) record a pronounced change in sediment dispersal from dominantly aeolian deposition with an Appalachian source (Entrada Sandstone) to dominantly fluvial deposi­tion with a source in the Mogollon and/or Sevier orogenic highlands (Salt Wash Member of the Morrison Formation). An enigmatic abundance of Cambrian (ca. 527–519 Ma) grains at this prove­nance transition in the CCT at Escalante Canyon, Colorado, was recently suggested to reflect a local sediment source from the Ancestral Front Range, despite previous interpretations that local base­ment uplifts were largely buried by Middle to Late Jurassic time. This study aims to delineate spatial and tem­poral patterns in provenance of these Jurassic sandstones containing Cambrian grains within the Paradox Basin and CCT using sandstone petrog­raphy, detrital zircon U-Pb geochronology, and detrital zircon trace elemental and rare-earth ele­mental (REE) geochemistry. We report 7887 new U-Pb detrital zircon analyses from 31 sandstone samples collected within seven transects in west­ern Colorado and eastern Utah. Three clusters of zircon ages are consistently present (1.53–1.3 Ga, 1.3–0.9 Ga, and 500–300 Ma) that are interpreted to reflect sources associated with the Appalachian orogen in southeastern Laurentia (mid-continent, Grenville, Appalachian, and peri-Gondwanan terranes). Ca. 540–500 Ma zircon grains are anom­alously abundant locally in the uppermost Entrada Sandstone and Wanakah Formation but are either lacking or present in small fractions in the overlying Salt Wash and Tidwell Members of the Morrison Formation. A comparison of zircon REE geochem­istry between Cambrian detrital zircon and igneous zircon from potential sources shows that these 540–500 Ma detrital zircon are primarily magmatic. Although variability in both detrital and igneous REE concentrations precludes definitive identifica­tion of provenance, several considerations suggest that distal sources from the Cambrian granitic and rhyolitic provinces of the Southern Oklahoma aulacogen is also likely, in addition to a proximal source identified in the McClure Mountain syenite of the Wet Mountains, Colorado. The abundance of Cambrian grains in samples from the central CCT, particularly in the Entrada Sandstone and Wana­kah Formation, suggests northwesterly sediment transport within the CCT, with sediment sourced from Ancestral Rocky Mountains uplifts of the southern Wet Mountains and/or Amarillo-Wichita Mountains in southwestern Oklahoma. The lack of Cambrian grains within the Paradox Basin sug­gests that the Uncompahgre uplift (southwestern Colorado) acted as a barrier to sediment transport from the CCT.

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