406 results on '"kimmeridgian"'
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2. First Record of Aff. Plesiosuchus sp. (Mesosuchia, Metriorhynchidae) in the Kimmeridgian of Le Havre (Normandy, North-Western France): Biometry, Profile of Locomotion, and Paleobiological Consequences.
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Stéphane, Hua
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SPINE , *VERTEBRAE , *ANIMAL experimentation , *BIOMETRY , *TEETH - Abstract
This is the first record of the biggest Metriorhynchidae, aff. Plesiosuchus sp. in France. The remains consist of a partial vertebral column consisting of 11 vertebrae and an ischium fragment. A new method is proposed to evaluate the individual's size, which is estimated at 6.5 m. This method, unlike previous approaches, is based only on vertebrae and yields results that are congruent with those based on cranial remains. The state of preservation has allowed us to test the animal's 'profile of locomotion' to better interpret how it moved. Concerning other metriorhynchids, the record of Dakosaurus in France based only on teeth must be reassessed, and the genus Torvoneustes, if valid, has to be distinguished from Plesiosuchus. [ABSTRACT FROM AUTHOR]
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- 2024
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3. EXCEPTIONAL AND STRIKING 3D TRACK-DETACHED UNDERTRACK SPECIMENS FROM THE UPPER JURASSIC OF ASTURIAS (N SPAIN)
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LAURA PIÑUELA, JOSÉ CARLOS GARCÍA-RAMOS, KAREN MORENO, GIUSEPPE LEONARDI, and OSCAR EUGENIO FINSTERBUSCH-LAGOS
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theropod footprints ,ornithopod-like undertracks ,taphonomic processes ,pedal kinematics ,Kimmeridgian ,Iguanodontipus. ,Geology ,QE1-996.5 ,Paleontology ,QE701-760 - Abstract
Vertebrate palaeoichnology often aims at the identification of the trackmaker by associating diagnostic features from the known taxa’s skeletal anatomy with its inferred footprint morphology, but deep penetrative tracks and/or deep, detached undertracks (DDU) are providing conflicting morphological/extra-morphological information, bringing into question the initially assumed close anatomical correlation. Penetrative footprints produced in fluvial-dominated deltaic facies from Upper Jurassic Lastres Formation are very frequent in the coastal cliffs of Asturias (N Spain). Some of them consist of non-avian theropod track casts associated with “ornithopod-like” detached undertracks. Some criteria are suggested to distinguish the latter when such an association does not exist. Moreover, we describe an exceptional theropod footprint preserved as a sandstone cast along with its respective deep detached sandstone undertrack (DDSU). The specimen records the foot movement through the sediment, entailing striking morphologic changes in outline along four different levels of depth. The uppermost level 1 shows an apparent stegosaur hind track morphology; level 2 resembles an avian-theropod print; level 3 represents the true non-avian theropod pedal morphology of the trackmaker; the lowermost level 4 corresponds to the deep detached sandstone undertrack (DDSU), which could be interpreted as either a track of a graviportal theropod or an ornithopod-like footprint. In light of this new evidence, it becomes clear that vertebrate ichnotaxonomy should not be based solely on the supposed trackmaker identification. Furthermore, biogeographic and evolutionary studies linked to this core information should be considered unsupported, along with many ichnotaxonomical assignations based on taphonomic processes, such as the case exemplified herein, the Iguanodontipus ichnogenus.
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- 2025
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4. Controls on the terrigenous fractions in Early Kimmeridgian shallow-water carbonate deposits in Southern Iberia
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Coimbra, Rute, Olóriz, Federico, and Rocha, Fernando
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- 2024
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5. Description and phylogenetic relationships of a new species of Torvoneustes (Crocodylomorpha, Thalattosuchia) from the Kimmeridgian of Switzerland.
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Girard, Léa C., Oliveira, Sophie De Sousa, Raselli, Irena, Martin, Jeremy E., and Anquetin, Jérémy
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PERSONAL names ,FIBULA ,SKULL ,VERTEBRAE ,AMELOBLASTS ,FEMUR ,RIB cage - Abstract
Metriorhynchids are marine crocodylomorphs found across Jurassic and Lower Cretaceous deposits of Europe and Central and South America. Despite being one of the oldest fossil families named in paleontology, the phylogenetic relationships within Metriorhynchidae have been subject to many revisions over the past 15 years. Herein, we describe a new metriorhynchid from the Kimmeridgian of Porrentruy, Switzerland. The material consists of a relatively complete, disarticulated skeleton preserving pieces of the skull, including the frontal, prefrontals, right postorbital, nasals, maxillae, right premaxillae and nearly the entire mandible, and many remains of the axial and appendicular skeleton such as cervical, dorsal, and caudal vertebrae, ribs, the left ischium, the right femur, and the right fibula. This new specimen is referred to the new species Torvoneustes jurensis sp. nov. as part of the large-bodied macrophagous tribe Geosaurini. Torvoneustes jurensis presents a unique combination of cranial and dental characters including a smooth cranium, a unique frontal shape, acute ziphodont teeth, an enamel ornamentation made of numerous apicobasal ridges shifting to small ridges forming an anastomosed pattern toward the apex of the crown and an enamel ornamentation touching the carina. The description of this new species allows to take a new look at the currently proposed evolutionary trends within the genus Torvoneustes and provides new information on the evolution of this clade. [ABSTRACT FROM AUTHOR]
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- 2023
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6. Late Jurassic back‐arc extension in the Neuquén Basin (37°S): Insights from structural, sedimentological and provenance analyses.
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Acevedo, Eliana, Fernández Paz, Lucía, Encinas, Alfonso, Horton, Brian K., Hernando, Agustín, Valencia, Victor, and Folguera, Andrés
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SUBDUCTION zones , *LAND subsidence , *SUBMARINE fans , *SEDIMENTATION & deposition , *GEOLOGICAL time scales , *SLABS (Structural geology) , *PROVENANCE (Geology) - Abstract
The Middle Jurassic–Early Cretaceous evolution of the Neuquén Basin is traditionally attributed to a long phase of thermal subsidence. However, recent works have challenged this model. In view of this, we study the Late Jurassic Tordillo Formation, a non‐marine depositional unit that marks a shift to regional regression across the basin. Previous studies propose different causes for this regression, including the growth of the magmatic arc in the west, uplift in the south or extension in the north. We studied the Tordillo Formation in sections located at an intermediate position in the Neuquén Basin, in order to understand the tectonic processes active during sedimentation. We present evidence of normal faulting within the Tordillo Formation and the base of the overlying Vaca Muerta Formation. Some of these faults can be attributed as syndepositional. We characterize the Tordillo Formation as part of a distal fan‐playa lake depositional system with a contemporaneous western magmatic arc as the main source of sediment. When compared to the Late Triassic–Early Jurassic NE to NNE‐oriented rifting, which marks the opening of the Neuquén Basin, the Late Jurassic extension shows a switch in stress orientation; the latter is orthogonal to the north‐trending subduction zone. We interpret this change as a renewed phase of back‐arc extension induced by slab rollback along with minor distributed intraplate extension prior to opening of the South Atlantic Ocean. [ABSTRACT FROM AUTHOR]
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- 2023
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7. A truly gigantic pliosaur (Reptilia, Sauropterygia) from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of England.
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Martill, David M., Jacobs, Megan L., and Smith, Roy E.
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Four isolated cervical vertebrae from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of Abingdon, Oxfordshire, England are identified as from a pliosaurid plesiosaurian sauropterygian on account of their shortness relative to width and height, their near platycoelous nature and the location of tall rib facets on the centrum body. They are noteworthy for their size, with a maximum width of 269 mm, maximum height of 222 mm and maximum length of 103 mm. Simple scaling and comparisons with cervical vertebrae of Mid Jurassic pliosaurs Peloneustes and Liopleurodon , and the Early Cretaceous Stenorhynchosaurus and Sachicasaurus suggest a total body length of between ~ 9.8 m and 14.4 m for the Abingdon Kimmeridge Clay pliosaur. Likely the true length was towards the higher end of this range. A genus and species cannot be confidently determined on the basis of the described material, but they likely belong to Pliosaurus sp. or a similar animal, for which a precise neck length is not known. We estimate a neck length of 0.77 m for Pliosaurus ? brachyspondylus based on the average cervical lengths provided for specimen CAMSM J.35991. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Major Kinematic Revolutions: The Underside of the Maps
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Aslanian, Daniel, Moulin, Maryline, Rabineau, Marina, Schnürle, Philippe, Leroux, Estelle, Pellen, Romain, Thompson, Joseph, Pisello, Anna Laura, Editorial Board Member, Hawkes, Dean, Editorial Board Member, Bougdah, Hocine, Editorial Board Member, Rosso, Federica, Editorial Board Member, Abdalla, Hassan, Editorial Board Member, Boemi, Sofia-Natalia, Editorial Board Member, Mohareb, Nabil, Editorial Board Member, Mesbah Elkaffas, Saleh, Editorial Board Member, Bozonnet, Emmanuel, Editorial Board Member, Pignatta, Gloria, Editorial Board Member, Mahgoub, Yasser, Editorial Board Member, De Bonis, Luciano, Editorial Board Member, Kostopoulou, Stella, Editorial Board Member, Pradhan, Biswajeet, Editorial Board Member, Abdul Mannan, Md., Editorial Board Member, Alalouch, Chaham, Editorial Board Member, O. Gawad, Iman, Editorial Board Member, Nayyar, Anand, Editorial Board Member, Amer, Mourad, Series Editor, Meghraoui, Mustapha, editor, Sundararajan, Narasimman, editor, Banerjee, Santanu, editor, Hinzen, Klaus-G., editor, Eshagh, Mehdi, editor, Roure, François, editor, Chaminé, Helder I., editor, Maouche, Said, editor, and Michard, André, editor
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- 2022
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9. A Synoptic Review of the Cartilaginous Fishes (Chondrichthyes: Holocephali, Elasmobranchii) from the Upper Jurassic Konservat-Lagerstätten of Southern Germany: Taxonomy, Diversity, and Faunal Relationships.
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Villalobos-Segura, Eduardo, Stumpf, Sebastian, Türtscher, Julia, Jambura, Patrick L., Begat, Arnaud, López-Romero, Faviel A., Fischer, Jan, and Kriwet, Jürgen
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FOSSILS , *TAXONOMY , *CHONDRICHTHYES , *ARCHIPELAGOES - Abstract
The Late Jurassic-Early Cretaceous (164–100 Ma) represents one of the main transitional periods in life history. Recent studies unveiled a complex scenario in which abiotic and biotic factors and drivers on regional and global scales due to the fragmentation of Pangaea resulted in dramatic faunal and ecological turnovers in terrestrial and marine environments. However, chondrichthyan faunas from this interval have received surprisingly little recognition. The presence of numerous entire skeletons of chondrichthyans preserved in several localities in southern Germany, often referred to as Konservat-Lagerstätten (e.g., Nusplingen and the Solnhofen Archipelago), provides a unique opportunity of to study the taxonomic composition of these assemblages, their ecological distributions and adaptations, and evolutionary histories in detail. However, even after 160 years of study, the current knowledge of southern Germany's Late Jurassic chondrichthyan diversity remains incomplete. Over the last 20 years, the systematic study and bulk sampling of southern Germany's Late Jurassic deposits significantly increased the number of known fossil chondrichthyan genera from the region (32 in the present study). In the present work, the fossil record, and the taxonomic composition of Late Jurassic chondrichthyans from southern Germany are reviewed and compared with several contemporaneous assemblages from other sites in Europe. Our results suggest, inter alia, that the Late Jurassic chondrichthyans displayed extended distributions within Europe. However, it nevertheless also is evident that the taxonomy of Late Jurassic chondrichthyans is in urgent need of revision. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. A large pterosaur femur from the Kimmeridgian, Upper Jurassic of Lusitanian Basin, Portugal
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FILIPPO BERTOZZO, BRUNO CAMILO DA SILVA, DAVID MARTILL, ELSA MARLENE VORDERWUELBECKE, TITO AURELIANO, REMMERT SCHOUTEN, and PEDRO AQUINO
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pterosauria ,dsungaripteroidea ,histology ,late jurassic ,kimmeridgian ,portugal ,Fossil man. Human paleontology ,GN282-286.7 ,Paleontology ,QE701-760 - Abstract
The pterosaur fossil record in Portugal is scarce, comprising mainly isolated teeth and rare postcranial material. Here, we describe a well-preserved right proximal femur of a pterodactyloid pterosaur from the Kimmeridgian, Upper Jurassic Praia da Amoreira–Porto Novo Formation of Peniche, Portugal. It is noteworthy for its relatively large size, compared to other Jurassic pterosaurs. It shows affinities with dsungaripteroids based on a combination of features including the bowing of the shaft, the mushroom-like cap of the femoral head, and the distinctly elevated greater trochanter. The femur has a relatively thinner bone wall compared to dsungaripterids, and is more similar to basal dsungaripteroids. A histological analysis of the bone cortex shows it had reached skeletal maturity. The preserved last growth period indicates fast, uninterrupted growth continued until the final asymptotic size was reached, a growth pattern which could best be compared to pterodactyloid femora from the Early Cretaceous. The specimen is the second confirmed report of a dsungaripteroid from the Jurassic, and it is the first record of this group from the Iberian Peninsula.
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- 2021
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11. Late Jurassic (Kimmeridgian) bivalves from northwestern Algeria (Daïa and Nador mountains): Systematics and palaeobiogeography.
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Frioui, Kamila, Ghenim, Asma Fethia, Benyoucef, Madani, Bouchemla, Imad, and Bensalah, Mustapha
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BIVALVES , *FOSSILS , *SPECIES , *AGE - Abstract
The bivalve fauna of the Upper Jurassic (Kimmeridgian) successions belonging to the Daïa and Nador mountains (NW Algeria) is taxonomically described and figured. For the first time, sixteen bivalve taxa were identified, partly in open nomenclature because of their poor state of preservation. Most taxa are represented by internal casts. The fauna was collected from two different formations of the same age: the Dolomies de Tlemcen Formation in the Daïa Mountains and the Faïdja Formation in the Nador Mountains. The lithologic characteristics of these formations, together with their fossil content and taphonomic features, confirm that these localities are characterized by marine conditions. The north-western Algerian bivalve assemblage holds the largest portion of cosmopolitan species. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Callovian − Kimmeridgian palynology and palaeobiogeography of the Essaouira − Agadir Basin (Moroccan Atlantic Margin).
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Jaydawi, Soukaina, Hssaida, Touria, Yousfi, Mohamed Zakaria, Maatouf, Wafaa, Chakir, Sara, Talih, Amine, Chafai, Khaoula, Khaffou, Hanane, and Benmlih, Abdelouahed
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DINOFLAGELLATE cysts , *TETHYS (Paleogeography) , *HYDROCARBON reservoirs , *PETROLEUM prospecting , *SEDIMENTARY basins - Abstract
The Jurassic formations within the Essaouira − Agadir Basin are of considerable interest for petroleum exploration, owing to their reservoir facies and hydrocarbon potentiality. These formations exhibit a scarcity of macrofossils, and their age is determined through lithological correlation. The Agadir − Essaouira Basin is a Mesozoic − Cenozoic sedimentary basin, part of the Tethyan Realm, precisely belonging to the Central Atlantic province which extends the Tethys westward. The material studied originates from five boreholes (GTE-1, MKL-110, NDK-2, NDK-3 and ESS-1) located at the center the basin along an East−West axis. The organic residue of the studied samples revealed a diverse dinoflagellate cyst assemblage with specific associations incorporating globally recognized marker taxa. The Early Callovian is distinguished by species such as: Ctenidodinium combazii , Ctenidodinium continuum, Ctenidodinium cornigerum , Dichadogonyaulax sellwoodii, and Impletosphaeridium varispinosum. The Late Callovian is characterized by the presence of marker cysts including: Compositosphaeridium polonicum, Endoscrinium galeritum Gonyaulacysta centriconnata, Liesbergia liesbergensis, Wanaea thysanota. The Early Oxfordian is marked by the association of species including: Gonyaulacysta jurassica subsp. jurassica , Rhynchodiniopsis cladophora , Scriniodinium crystallinum, Systematophora areolata , Systematophora penicillata , and Trichodinium scarburghense. The Late Oxfordian to basal Kimmeridgian is characterized by an association of dinoflagellate cysts including: Cribroperidinium globatum, Dichadogonyaulax? panneum, Downiesphaeridium polytrichum, Egmontodinium polyplacophorum, Endoscrinium galeritum , Gochteodinia mutabilis, Perisseiasphaeridium pannosum, Prolixosphaeridium anasillum, Scriniodinium crystallinum, Systematophora areolata, Systematophora penicillata, Surculosphaeridium vestitum, Systematophora? daveyi, and Wallodinium krutzschii. Our associations have been correlated with those in contemporary basins within other paleogeographic realms, contributing to the formulation of a global paleobiogeographic pattern. This pattern complements previous research on the distribution of dinoflagellate cysts during the Callovian − Early Kimmeridgian time interval. • Jurassic sections of five boreholes in Essaouira − Agadir Basin of Moroccan Atlantic Margin were studied palynologically. • The studied wells are palynostratigraphically correlated with that in other palaeogeographic areas. • Contribution to the reconstruction of the global palaeobiogeographic pattern of the distribution of dinoflagellate cysts. [ABSTRACT FROM AUTHOR]
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- 2024
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13. TARAMELLICERATINAE (Taramelliceras) SPECIES FROM THE UPPER JURASSIC DEPOSITS OF HĂGHIMAȘ MTS. (EAST CARPATHIANS - ROMANIA).
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Dan, GRIGORE
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SPECIES , *AMMONOIDEA - Abstract
The paper presents description of the eleven species of the subgenus Taramelliceras (Taramelliceras) Del Campana 1904 found in the Formation of "Acanthicum Beds" (Kimmeridgian) from Ghilcoș (Hăghimaș Mountains, Romania). The species T. trachinotum (Opp.), T. erycinum (Gemm.), T. mikoi (Herb.) and T. pugile (Neum.) have been previously described from this region by previous authors, the last two (T. mikoi and T. pugile) being recorded for a first time and one, (T. pugile pseudopugile Sarti), is determined on the base of specimens from Preda Colection In addition to the species listed, now there are six other species that enrich the association: T. greenackeri (Moesch), T. pseudoflexuosum (Fav.), T. cf. platyconcha (Gemm.), T. af. subcallicerum (Gemm.) and T. pugilepugiloides (Canav.), unknown in the region until now. [ABSTRACT FROM AUTHOR]
- Published
- 2022
14. The geologically oldest specimen of Pterodactylus: a new exquisitely preserved skeleton from the Upper Jurassic (Kimmeridgian) Plattenkalk deposits of Painten (Bavaria, Germany).
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Augustin, Felix J., Kampouridis, Panagiotis, Hartung, Josephina, Albersdörfer, Raimund, and Matzke, Andreas T.
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SKELETON , *NUMBERS of species , *PTEROSAURIA , *OLD age , *HUMAN skeleton , *SKULL - Abstract
Pterodactylus from the uppermost Jurassic of southern Germany represents one of the most iconic pterosaurs, due to its status of being the first member of the Pterosauria to have been described and named. During the early phase of pterosaur research, Pterodactylus was a wastebasket taxon containing dozens of sometimes distantly related assigned species. Decades later, a comprehensive revision of the genus significantly reduced the number of species. To date, only one species remains in the genus, Pterodactylus antiquus, although the referral of several specimens to this taxon and the taxonomic relationships of them is still debated. Thus far, the genus has been only reported from the Upper Jurassic Plattenkalk deposits of Bavaria, and all of these occurrences are Tithonian in age. Here we describe the first record of Pterodactylus from the Torleite Formation near Painten (Bavaria), which represents the first occurrence of the genus from the Kimmeridgian. The specimen is a complete, articulated and exquisitely preserved skeleton of a small-sized individual. Aside from its old geological age, it is a typical representative of the genus, greatly resembling other specimens from younger strata. Certain characters, such as the overall size, skull length, relative orbit size, and phalangeal formula indicate that the specimen from Painten represents a juvenile to young subadult individual, an ontogenetic stage rarely found among Pterodactylus specimens. The find significantly expands the temporal range of the taxon and represents one of the best-preserved specimens of the genus reported so far. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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15. Life at the continental–marine interface: palaeoenvironments and biota of the Alcobaça Formation (Late Jurassic, Central Portugal), with a formal definition of the unit appended.
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Fürsich, Franz T., Schneider, Simon, Werner, Winfried, Lopez-Mir, Berta, and Pierce, Colm S.
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The Kimmeridgian Alcobaça Formation of the Lusitanian Basin forms a mixed carbonate–siliciclastic unit between basinal deposits of the Abadia Formation, and fluvial–terrestrial strata of the Lourinhã Formation. This study presents >2.5 km of detailed logs of nine outcrop sections of the Alcobaça Formation in its type region. Eight of these sections encircle the Caldas da Rainha Diapir, which was a prominent, emergent, passive salt diapir during the time of deposition. Palaeoenvironments of the unit form a complex mosaic of low- to high-energy, carbonate- or siliciclastic-dominated shallow shelf settings; coastal embayments and lagoons; and coastal plains with rivers, lakes and playas. In the strata, abundant microfauna is often joined by a rich macrofauna, usually dominated by bivalves. Locally, corals, calcareous sponges or oysters form meadows or patch reefs. These autochthonous to parautochthonous remnants of former communities are assigned to 35 benthic macrofaunal associations. The integration of palaeoecological analysis of these associations with microfaunal and sedimentological data provides constraint on their salinity ranges, which range from slightly hypersaline to freshwater. Frequent temporal and spatial salinity fluctuations are attributed to variations in relative sea-level, salt tectonics or climate. The NNE-trending Caldas da Rainha Diapir induced pronounced facies differentiation. Predominantly, non-marine siliciclastic facies in the northwest and carbonate to siliciclastic, marine to brackish facies in the southwest are contrasted by shallow-marine carbonate facies east of the diapir. Comprehensive exposure and well-preserved fossils make the Alcobaça Formation an excellent showcase to demonstrate how biofacies analysis can help to disentangle the interplay of climate changes, sea-level fluctuations and salt tectonics. Based on the improved characterisation of the unit, the Alcobaça Formation is formally defined, and seven members are established. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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16. The giant pliosaurid that wasn’t—revising the marine reptiles from the Kimmeridgian, Upper Jurassic, of Krzyżanowice, Poland
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Daniel Madzia, Tomasz Szczygielski, and Andrzej S. Wolniewicz
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pliosauridae ,metriorhynchidae ,crocodylomorpha ,thalassochelydia ,kimmeridgian ,jurassic ,poland ,Fossil man. Human paleontology ,GN282-286.7 ,Paleontology ,QE701-760 - Abstract
Marine reptiles from the Upper Jurassic of Central Europe are rare and often fragmentary, which hinders their precise taxonomic identification and their placement in a palaeobiogeographic context. Recent fieldwork in the Kimmeridgian of Krzyżanowice, Poland, a locality known from turtle remains originally discovered in the 1960s, has reportedly provided additional fossils thought to indicate the presence of a more diverse marine reptile assemblage, including giant pliosaurids, plesiosauroids, and thalattosuchians. Based on its taxonomic composition, the marine tetrapod fauna from Krzyżanowice was argued to represent part of the “Matyja-Wierzbowski Line”—a newly proposed palaeobiogeographic belt comprising faunal components transitional between those of the Boreal and Mediterranean marine provinces. Here, we provide a detailed re-description of the marine reptile material from Krzyżanowice and reassess its taxonomy. The turtle remains are proposed to represent a “plesiochelyid” thalassochelydian (Craspedochelys? sp.) and the plesiosauroid vertebral centrum likely belongs to a cryptoclidid. However, qualitative assessment and quantitative analysis of the jaws originally referred to the colossal pliosaurid Pliosaurus clearly demonstrate a metriorhynchid thalattosuchian affinity. Furthermore, these metriorhynchid jaws were likely found at a different, currently indeterminate, locality. A tooth crown previously identified as belonging to the thalattosuchian Machimosaurus is here considered to represent an indeterminate vertebrate. The revised taxonomy of the marine reptiles from Krzyżanowice, as well as the uncertain provenance of the metriorhynchid specimen reported from the locality, cast doubt on the palaeobiogeographic significance of the assemblage.
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- 2021
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17. Tracking Late Jurassic ornithopods in the Lusitanian Basin of Portugal: Ichnotaxonomic implications
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Diego Castanera, Bruno C. Silva, Vanda F. Santos, Elisabete Malafaia, and Matteo Belvedere
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iguanodontipodidae ,dinehichnus ,anomoepus-like ,kimmeridgian ,tithonian ,europe ,Fossil man. Human paleontology ,GN282-286.7 ,Paleontology ,QE701-760 - Abstract
The Sociedade de História Natural in Torres Vedras, Portugal houses an extensive collection of as yet undescribed dinosaur tracks with ornithopod affinities. They have been collected from different Late Jurassic (Kimmeridgian–Tithonian) geological formations (Praia de Amoreira-Porto Novo, Alcobaça, Sobral, and Freixial) that outcrop along the Portuguese coast, and belong to two different sub-basins of the Lusitanian Basin (the Consolação and Turcifal sub-basins). Three main morphotypes can be distinguished on the basis of size, mesaxony and the morphology of the metatarsophalangeal pad impression. The minute to small-sized morphotype is similar to the Anomoepus-like tracks identified in other Late Jurassic areas. The small to medium-sized morphotype resembles the Late Jurassic–Early Cretaceous ichnotaxon Dinehichnus, already known in the Lusitanian Basin. Interestingly, these two morphotypes can be distinguished qualitatively (slightly different size, metatarsophalangeal pad impression and digit morphology) but are nevertheless difficult to discriminate by quantitatively analysing their length-width ratio and mesaxony. The third morphotype is considered a large ornithopod footprint belonging to the ichnofamily Iguanodontipodidae. This ichnofamily is typical for Cretaceous tracksites but the new material suggests that it might also be present in the Late Jurassic. The three morphotypes show a negative correlation between size and mesaxony, so the smaller tracks show the stronger mesaxony, and the larger ones weaker mesaxony. The Upper Jurassic ornithopod record from the Lusitanian Basin has yielded both small and medium-sized ornithopod remains, mainly iguanodontians such as dryosaurids and ankylopollexians, which are the main candidates to be the trackmakers.
- Published
- 2020
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18. New erymid lobsters from the Nusplingen and Usseltal formations (Upper Jurassic) of southwest Germany
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Günter SCHWEIGERT and Jürgen HÄRER
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decapoda ,erymidae ,kimmeridgian ,tithonian ,plattenkalk ,taphonomy ,Geology ,QE1-996.5 - Abstract
Two new species of Late Jurassic erymid lobsters, Stenodactylina devillezi sp. nov. and Stenodactylina geigerae sp. nov., are described on the basis of isolated, but well-preserved chelipeds from the upper Kimmeridgian of Swabia and the lower Tithonian of Bavaria, respectively. The incomplete nature of the material indicates that these lobsters were not autochthonous elements of the Plattenkalk lagoons, but resulted from predation in nearby shallow-water settings.
- Published
- 2020
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19. Sauropod Trackway Morphometrics: An Exploratory Study Using Highway A16 Excavation at the Courtedoux-Tchâfouè Track Site (Late Jurassic, NW Switzerland)
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Lara Sciscio, Matteo Belvedere, Christian A. Meyer, and Daniel Marty
- Subjects
geometric morphometrics ,sauropoda ,parabrontopodus ,dinosaur track ,tidal flat ,Kimmeridgian ,Science - Abstract
Ichnogeneric classification of sauropod trackways is determined using qualitative and quantitative descriptions of morphological parameters. More recently, the validity of several of these parameters has been called into question (e.g., trackway gauge). This paper aims to test traditional and more novel landmark-based geometric morphometric (GM) analysis to describe sauropod tracks and trackways. The Courtedoux-Tchâfouè (TCH) tracksite, in NW Switzerland, has been used as a test site because it hosted several Late Jurassic sauropod track-bearing levels, over a short time period (∼40 ka), creating a time capsule of sauropod activity. Exploratory statistical analyses suggest that the TCH trackway dataset can be partitioned into clusters based on trackway parameters (e.g., width of pes angulation pattern/pes length) that demonstrate differences between trackways. Nevertheless, clustering reflected a moderate degree of intercluster similarity and a continuum in TCH trackway morphologies. The GM analysis of TCH pes impressions, from several trackways, indicates a similar morphotype and did not significantly differentiate pes tracks from various stratigraphic levels. Currently, the results indicate that neither linear nor landmark-based geometric morphometric methods strongly segregate tracks at TCH nor show a time-control (i.e., via stratigraphic level) over the short interval studied. The methods reinforce that sauropod pes impression shape is conservative and that combining morphological methods to be inclusive of sauropod trackway data is important. The TCH site demonstrates that variability may reflect morphological continuums and behavioural factors and does not unambiguously differentiate unique sauropod trackmakers. More exploration on the minimum number of trackway parameters as predictors of sauropod ichnotaxonomy is needed. Integrating complementary techniques will provide more insight and practical means of identification and delineation of sauropod tracks and their trackways.
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- 2022
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20. Changing depositional environments in the semi-restricted Late Jurassic Lemeš Basin (Outer Dinarides; Croatia).
- Author
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Vitzthum, Michael A. J., Gawlick, Hans-Jürgen, Sachsenhofer, Reinhard F., and Neumeister, Stefan
- Subjects
- *
SEDIMENTARY rocks , *SEDIMENTATION & deposition , *STABLE isotopes , *MACERAL , *ACOUSTIC Doppler current profiler , *CHEMOSTRATIGRAPHY , *KEROGEN - Abstract
The up to 450 m-thick Upper Jurassic Lemeš Formation includes organic-rich deep-water (max. ~ 300 m) sedimentary rocks deposited in the Lemeš Basin within the Adriatic Carbonate Platform (AdCP). The Lemeš Formation was investigated regarding (1) bio- and chemostratigraphy, (2) depositional environment, and (3) source rock potential. A multi-proxy approach—microfacies, Rock–Eval pyrolysis, maceral analysis, biomarkers, and stable isotope ratios—was used. Based on the results, the Lemeš Formation is subdivided from base to top into Lemeš Units 1–3. Deposition of deep-water sediments was related to a late Oxfordian deepening event causing open-marine conditions and accumulation of radiolarian-rich wackestones (Unit 1). Unit 2, which is about 50 m thick and Lower early Kimmeridgian (E. bimammatum to S. platynota, ammonite zones) in age, was deposited in a restricted, strongly oxygen-depleted basin. It consists of radiolarian pack- and grainstones with high amounts of kerogen type II-S organic matter (avg. TOC 3.57 wt.%). Although the biomass is predominantly marine algal and bacterial in origin, minor terrestrial organic matter that was transported from nearby land areas is also present. The overlying Unit 3 records a shallowing of the basin and a return to oxygenated conditions. The evolution of the Lemeš Basin is explained by buckling of the AdCP due to ophiolite obduction and compressional tectonics in the Inner Dinarides. Lemeš Unit 2 contains prolific oil-prone source rocks. Though thermally immature at the study location, these rocks could generate about 1.3 t of hydrocarbon per m2 surface area when mature. [ABSTRACT FROM AUTHOR]
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- 2022
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- View/download PDF
21. Late Jurassic (Upper Kimmeridgian) Heterobranchia (Gastropoda) of the coral-facies of Saal near Kelheim and the viciniy of Nattheim (Germany).
- Author
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Gründel, Joachim, Keupp, Helmut, Lang, Fritz, and Nützel, Alexander
- Subjects
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GASTROPODA , *CORAL reefs & islands , *INVERTEBRATES , *ANIMALS - Abstract
Forty gastropod species of the subclass Heterobranchia are described from the Upper Jurassic (Upper Kimmeridgian) reefal limestones of South Germany, including ten species in open nomenclature and further ten species of uncertain identity. Six species are new to science: Ceritella convexa sp. nov., Nerinea donosa sp. nov., Endoplocus acutus sp. nov., Endoplocus inflatus sp. nov., Pseudonerinea? pseudomelaniformis sp. nov., and Itieroptygmatis cylindrata sp. nov. A lectotype is designated for Ptygmatis? tornata (Quenstedt, 1852). With this final part of the study of the Late Jurassic gastropods from Saal and the Nattheim area, a total of 156 species have been reported. Of these species, 125 have been reported from Saal and 54 from the Nattheim area. Only 23 species occur in both Saal and the Nattheim area. The sample sizes (number of specimens) from Saal and the Nattheim area differ considerably and few species are shared. Diversity metrics suggest the same high diversity at both sites. The gastropod fauna from the Saal quarry has yielded particularly much new information - all new species are based on specimens from Saal. With 125 gastropod species from a single outcrop, the diversity at the Saal quarry is the highest from the Kimmeridgian worldwide. In total, up to 300 species of marine macro-invertebrates have been reported from this quarry, which is a very high point diversity. Gastropods are by far the most diverse group from Saal, which is a modern aspect of this fauna. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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22. New Late Jurassic Saturnalidae (Radiolaria) of the Arctic and Pacific Margins (Russia).
- Author
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Vishnevskaya, V. S.
- Abstract
Numerous radiolarians of the family Saturnalidae have been identified in the Yamal Peninsula (South Tambey Region) at the depth interval of 3352.4–3354.6 m in the Lower Volgian cherty limestones. Saturnalids are found for the first time in the Jurassic of the Arctic margin of Siberia; they were previously known from the Jurassic only in the Pacific margin of Russia. Jurassic radiolarians from saturnalids are systematically described. These include one new genus Acanthocircularis gen. nov. with five new species A. arcticus sp. nov., A. polaris sp. nov., A. sibiricus sp. nov., A. solis sp. nov., A. yamalensis sp. nov., four new species of the genus Spongosaturninus (S. cornutus sp. nov., S. cristatus sp. nov., S. trispinus sp. nov. and S. volgensis sp. nov.), and one new species of Eospongosaturninus(E. ovalis sp. nov.). The diagnoses of two radiolarian species have been supplemented: Spongosaturninus bispinus Yao, 1972, emend. nov. and S. meyerhofforum (Hull, 1997), emend. nov. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
23. A large pterosaur femur from the Kimmeridgian, Upper Jurassic of Lusitanian Basin, Portugal.
- Author
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BERTOZZO, FILIPPO, CAMILO DA SILVA, BRUNO, MARTILL, DAVID, VORDERWUELBECKE, ELSA MARLENE, AURELIANO, TITO, SCHOUTEN, REMMERT, and AQUINO, PEDRO
- Subjects
FEMUR ,FEMUR head ,FOSSILS ,SKELETAL maturity ,PTEROSAURIA ,FOSSIL hominids - Abstract
The pterosaur fossil record in Portugal is scarce, comprising mainly isolated teeth and rare postcranial material. Here, we describe a well-preserved right proximal femur of a pterodactyloid pterosaur from the Kimmeridgian, Upper Jurassic Praia da Amoreira-Porto Novo Formation of Peniche, Portugal. It is noteworthy for its relatively large size, compared to other Jurassic pterosaurs. It shows affinities with dsungaripteroids based on a combination of features including the bowing of the shaft, the mushroom-like cap of the femoral head, and the distinctly elevated greater trochanter. The femur has a relatively thinner bone wall compared to dsungaripterids, and is more similar to basal dsungaripteroids. A histological analysis of the bone cortex shows it had reached skeletal maturity. The preserved last growth period indicates fast, uninterrupted growth continued until the final asymptotic size was reached, a growth pattern which could best be compared to pterodactyloid femora from the Early Cretaceous. The specimen is the second confirmed report of a dsungaripteroid from the Jurassic, and it is the first record of this group from the Iberian Peninsula. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. A reevaluation of the Late Jurassic dinosaur tracksite Barkhausen (Wiehengebirge, Northern Germany).
- Author
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Meyer, Christian A., Belvedere, Matteo, Englich, Benjamin, and Lockley, Martin G.
- Abstract
A restudy of the Barkhausen dinosaur tracksite shows that the track-bearing surface reveals considerably more detail than previously indicated, and a new map is presented, showing the trackways of nine sauropods, traveling north, possibly as a group. These are among the smallest sauropod tracks recorded in Europe. There is also evidence of two large theropods crossing the area, one moving to the south and the other to the west. Evidence of at least three other sauropods is registered in the form of isolated manus traces that represent larger individuals. Previous interpretations inferred that sauropod trackways trended south, and therefore suggested a predator chasing its prey as in the purported but controversial attack scenario claimed for the famous Paluxy River site in Texas. Based on the present study, this scenario is no longer tenable for the Barkhausen tracksite. The description of Elephantopoides barkhausensis (Kaever and Lapparent, 1974) shows that it represents a moderately wide gauge, but small manus sauropod and can be assigned under the ichnofamily label Parabrontopodidae. E. barkhausensis as originally defined was a nomen dubium, but it has since been re-described semi-formally, without renaming, we emend the description and assigned them to the ichnotaxon Parabrontopodus barkhausensis comb. nov. These tracks could have been produced by the small sauropod dinosaur taxon Europasaurus. The problematic ichnotaxon Megalosauropus teutonicus (Kaever and Lapparent, 1974), which represents a large three-toed theropod, is assigned to the recently described ichnogenus Jurabrontes from the Late Kimmeridgian of the Swiss Jura mountains as Jurabrontes teutonicus comb. nov. Furthermore, we attribute the theropod tracks from the time equivalent Langenberg quarry to the same ichnotaxon. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. Sphenofontis velserae gen. et sp. nov., a new rhynchocephalian from the Late Jurassic of Brunn (Solnhofen Archipelago, southern Germany).
- Author
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Villa, Andrea, Montie, Roel, Röper, Martin, Rothgaenger, Monika, and Rauhut, Oliver W. M.
- Subjects
FOSSIL vertebrates ,ARCHIPELAGOES ,MESOZOIC Era - Abstract
The Solnhofen Archipelago is well known for its fossil vertebrates of Late Jurassic age, among which figure numerous rhynchocephalian specimens, representing at least six and up to nine genera. A new taxon, named Sphenofontis velserae gen. et sp. nov., increases rhynchocephalian diversity in the Solnhofen Archipelago and is herein described based on a single, well-preserved specimen originating from the Late Kimmeridgian of the Brunn quarry, near Regensburg. The exquisite preservation of the holotype allowed a detailed description of the animal, revealing a skeletal morphology that includes both plesiomorphic and derived features within rhynchocephalians. Sphenofontis is herein referred to Neosphenodontia and tentatively to sphenodontine sphenodontids. It notably differs from all other rhynchocephalians known from the Jurassic of Europe, showing instead closer resemblance with the Middle Jurassic Cynosphenodon from Mexico and especially the extant Sphenodon. This is evidence for a wide distribution of taxa related to the extant tuatara early in the Mesozoic, and also for the presence of less-specialized rhynchocephalians coexisting with more derived forms during the earliest time in the history of the Solnhofen Archipelago. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
26. Variability of continental depositional systems during lowstand sedimentation: an example from the Kimmeridgian of the Neuquen Basin, Argentina
- Author
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Luis A. Spalletti and Gonzalo D. Veiga
- Subjects
Fluvial-aeolian interactions ,Kimmeridgian ,Lowstand wedges ,Neuquén Basin ,Argentina. ,Geology ,QE1-996.5 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
Several second order lowstand wedges are recognized in the Jurassic-Early Cretaceous sedimentary record of the backarc Neuquén Basin (central-west Argentina). They are distinguished by sharp based continental and marginal marine siliciclastic deposits encased in offshore shales. The Kimmeridgian lowstand wedge was developed slightly after the emergence of the Andean magmatic arc and the tectonic inversion of previous intrabasinal extensional structures. As a result, the Neuquén Basin was compartmentalized into three main depocentres characterised by widespread continental sedimentation under arid to semiarid climatic conditions. A fluvial-dominated system characterised by systematic downstream changes in architectural style is recognized in the Northwestern Depocentre. A gravely and sandy bedload fluvial system was developed in the southern upstream sector, while ticker beds of finer-grained sediments formed in a distal ephemeral fluvial system prevail in the downstream part of the system. The overall fining upward stacking pattern of the sedimentary record in the Northwestern Depocentre accompanied by frequent development of soil horizons and darker deposits suggests a change towards higher accommodation and high water table emplacement. In the Southwestern and Eastern Depocentres, the sedimentary successions show a conspicuous internal transition from fluvial ephemeral fluvial systems to aeolian systems. However, the lowstand deposits of the Eastern Depocentre are characterised by a larger areal distribution and a thicker record of both the fluvial and the aeolian deposits. Marked changes in thickness and in the depositional style of the fluvial and aeolian facies associations within the Southwestern and Eastern depocentres indicate that the sedimentary infill was controlled by systematic variations in accommodation. Low accommodation conditions favoured a high degree of lateral migration of fluvial channels with substantial erosion of fine-grained deposits and the development of sinuous-crested aeolian dunes typically associated with wet interdune deposits. Under higher accommodation conditions the fluvial deposits show a retrogradational stacking with preservation of thick packages of fine-grained sediments, while a large sand sea characterised by amalgamation of dune deposits was developed in the aeolian-dominated uppermost successions. The detailed analysis of the Kimmeridgian lowstand wedge of the Neuquén Basin illustrates how facies and stratigraphic organisation responded to regional and temporal changes in basin configuration, accommodation, sediment supply and water table position. The Kimmeridgian lowstand deposits are geographically distributed as the subsequent transgressive deposits and reveal no major basinward shift during the early stages of sequence stacking. However, they show a much more complicated facies distribution. Consequently, the lowstand wedge deposits better reflect the complex interplay of episodic local tectonism, siliciclastic source area variation and climatic change.
- Published
- 2021
27. New dinosaur, crocodylomorph and swim tracks from the Late Jurassic of the Lusitanian Basin: implications for ichnodiversity.
- Author
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Castanera, Diego, Malafaia, Elisabete, Silva, Bruno C., Santos, Vanda F., and Belvedere, Matteo
- Subjects
- *
SAURISCHIA , *DINOSAURS , *GEOLOGICAL formations , *SWIMMING - Abstract
New dinosaur (theropod and sauropod), crocodylomorph and swim tracks from Upper Jurassic units of the Lusitanian Basin, housed at the Sociedade de História Natural in Torres Vedras, are here described. They were collected from three different geological formations, the Praia da Amoreira‐Porto Novo (upper Kimmeridgian) and the Alcobaça (Kimmeridgian‐lower Tithonian) formations in the Consolação Sub‐basin and the Freixial Fm. (middle‐upper Tithonian) in the Turcifal Sub‐basin. Four different theropod morphotypes are identified as follows: cf. Jurabrontes isp., Megalosauripus cf. transjuranicus, Grallatoridae indet. and an indeterminate morphotype (Theropoda indet.) that have affinities with other Therangospodus‐like tracks described in Europe. An indeterminate sauropod track is also identified. These five morphotypes suggest high saurischian dinosaur ichnodiversity, similar to that seen in other European Late Jurassic areas (e.g. the Swiss Jura Mountains), but represent just a portion of the higher diversity exhibited by the osteological record in the Lusitanian Basin. Further, one crocodylomorph pes track identified as Crocodylopodus isp. and swim tracks assigned to Characichnos isp., possibly also produced by crocodylomorphs, are also identified. The newly identified ichnotaxa, together with the older and other recent identifications, indicate ichnodiversity comparable with the richest coeval Upper Jurassic units. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
28. A new species of the large-headed coastal marine turtle Solnhofia (Testudinata, Thalassochelydia) from the Late Jurassic of NW Switzerland
- Author
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Jérémy Anquetin and Christian Püntener
- Subjects
Solnhofia ,Thalassochelydia ,Testudinata ,Kimmeridgian ,Late Jurassic ,Switzerland ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Background The large-headed turtle Solnhofia parsonsi is known by a handful of specimens from the Late Jurassic of Germany and Switzerland (maybe also France). Solnhofia parsonsi is traditionally regarded as a “eurysternid” Thalassochelydia, a group of small to medium sized, mostly lagoonal or marginal turtles found almost exclusively in the Late Jurassic of Europe. More recently, Solnhofia parsonsi has been proposed to be a close relative of Sandownidae, an enigmatic group of Cretaceous to Paleogene turtles characterized by a derived cranial anatomy and a wider geographical distribution. Sandownids may therefore have evolved from thalassochelydian ancestors such as Solnhofia parsonsi. Methods We herein describe new material of Solnhofia from the Kimmeridgian (Late Jurassic) of Porrentruy, NW Switzerland. The bulk of the material consists of an association of a cranium and over 180 shell bones found together in a block of marly limestone. A second cranium and a mandible from slightly younger, but nearby localities are also described. Results We refer the new material to Solnhofia brachyrhyncha n. sp. The new species shares with Solnhofia parsonsi a relatively large head, an extensive secondary palate formed primarily by the maxillae, a greatly developed processus trochlearis oticum with a contribution from the parietal and quadratojugal, a large jugal-palatine contact in the floor of the fossa orbitalis, and a posteromedial process of the jugal running on the dorsal surface of the maxilla and pterygoid. Some of these characteristics are also present in sandownids, but our morphological study clearly shows that Solnhofia brachyrhyncha is closer to Solnhofia parsonsi than to any sandownids. Discussion Solnhofia brachyrhyncha differs from Solnhofia parsonsi in many aspects, notably: a shortened and broader cranium, a shorter and posteriorly broader upper triturating surface with a slightly sinusoidal lateral margin and without contribution from the palatine, a processus trochlearis oticum more oblique in dorsal or ventral view and less concave in anterior view, choanae that do not extend posteriorly on the pterygoids, a more developed processus pterygoideus externus, a condylus mandibularis situated anterior to the level of the occipital plane, a greater ventral exposure of the parabasisphenoid, a mandible about as wide as long, a relatively short symphysis, a lower triturating surface widened posterolaterally thanks to the presence of large laterally projecting dentary tubercles, a stouter and shorter coronoid process, a splenial positioned more anteriorly along the mandibular ramus, costo-peripheral fontanelles extending more anteriorly and posteriorly along the costal series, and an escutcheon shaped central plastral fontanelle formed mostly by the hypoplastra. In addition to the morphology of the new species, we also briefly discuss about observable ontogenetic variations and possible taphonomic origin of the assemblage.
- Published
- 2020
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- View/download PDF
29. EVIDENCE OF OPPORTUNISTIC FEEDING BETWEEN ICHTHYOSAURS AND THE OLDEST OCCURRENCE OF THE HEXANCHID SHARK NOTIDANODON FROM THE UPPER JURASSIC OF NORTHERN ITALY
- Author
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GIOVANNI SERAFINI, JACOPO AMALFITANO, MIRIAM COBIANCHI, BEATRICE FORNACIARI, ERIN E. MAXWELL, CESARE ANDREA PAPAZZONI, GUIDO ROGHI, and LUCA GIUSBERTI
- Subjects
Taphonomy ,scavenging ,Ophthalmosauridae ,Hexanchidae ,Kimmeridgian ,UV-light. ,Geology ,QE1-996.5 ,Paleontology ,QE701-760 - Abstract
In 2016, two fossil marine reptiles were re-discovered in the collections of the Museo Civico di Storia Naturale di Verona. Originally recovered near Asiago, Vicenza province (northern Italy) from an outcrop of the Rosso Ammonitico Veronese Fm. (Middle-Upper Jurassic), they were never described. Morphological analysis carried out under UV-light allowed enhancing contrast with the surrounding matrix and better identifying some anatomical details. Both specimens consist of partially articulated postcranial elements from two distinct ichthyosaurs, including vertebrae, ribs, and some fragmentary elements of the appendicular skeleton. The first specimen V7101 is here tentatively assigned to Ophthalmosauridae based on a combination of features shared with other taxa in this family, such as the regionalization of the vertebral column. Taphonomical analysis suggests a long exposure of the carcass on the sea floor before burial; two teeth of the hexanchiform shark Notidanodon found near the ribcage could indicate scavenging. An ichthyosaur tooth most probably not belonging to the same specimen was found stuck on a rib and can also be attributed to scavenging – the first ever record of this interaction between two ichthyosaurs. The second specimen V7102 is represented by a poorly preserved partial vertebral column and is here referred to Ichthyosauria indet. due to the absence of taxonomically significant characters. Calcareous nannofossil data and microfacies analyses allow us to assign both specimens to the basal Kimmeridgian. This makes the two Notidanodon teeth associated with V7101 the oldest recorded occurrence of this genus.
- Published
- 2020
- Full Text
- View/download PDF
30. Petroleum geology of the Upper Jurassic – Lower Cretaceous of East and North-East Greenland: Blokelv-1 borehole, Jameson Land Basin: Biostratigraphy of the Hareelv Formation (Upper Jurassic) in the Blokelv-1 core, Jameson Land, central East Greenland
- Author
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Peter Alsen and Stefan Piasecki
- Subjects
Jameson Land Basin ,East Greenland ,ammonites ,dinoflagellate cysts ,biostratigraphy ,chronostratigraphy ,Oxfordian ,Kimmeridgian ,Geology ,QE1-996.5 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
The Hareelv Formation in the Blokelv-1 core is biostratigraphically subdivided by means of ammonite and dinoflagellate cyst stratigraphy. The succession ranges from the Oxfordian C. densiplicatum Chronozone to the Volgian P. elegans Chronozone. The mudstones of the Blokelv-1 core are characterised by large amounts of amorphous organic matter. This hampers the preparation and identification of dinoflagellate cysts, which are also commonly degraded and corroded. Ammonites, on the other hand, are common and well-preserved in the core, contrasting with that observed in the equivalent facies and stratigraphic interval at outcrop. Integration of the ammonite and dinoflagellate cyst biostratigraphical data yields a robust chronostratigraphic subdivision of the middle Oxfordian – lowermost Volgian cored section.
- Published
- 2018
31. Revision of Nannopterygius (Ichthyosauria: Ophthalmosauridae): reappraisal of the 'inaccessible' holotype resolves a taxonomic tangle and reveals an obscure ophthalmosaurid lineage with a wide distribution.
- Author
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Zverkov, Nikolay G and Jacobs, Megan L
- Subjects
- *
NATURAL history museums - Abstract
The Late Jurassic ichthyosaur Nannopterygius is among the poorest known, with the only skeleton, NHMUK PV 46497, on display in the Natural History Museum, London and, therefore, difficult to access. This holotype specimen is here reassessed. The newly obtained data have enabled the identification of several additional specimens of Nannopterygius in museum collections across the UK. Furthermore, all the material of Russian ichthyosaurs previously referred to genera Paraophthalmosaurus and Yasykovia , and considered as junior synonyms of Ophthalmosaurus in the majority of subsequent works, are also reassessed. Both these genera are synonymized with Nannopterygius with preservation of the two from six originally erected species: Nannopterygius saveljeviensis comb. nov. and Nannopterygius yasykovi comb. nov. Additionally, a new species from the Berriasian of Arctic (Svalbard and Franz Josef Land) is proposed. To resolve the phylogenetic relations within Ophthalmosauria, a revised dataset, including 44 taxa and 134 characters, 20 of which are new, was compiled. The results of a phylogenetic analysis places Nannopterygius spp. as sister to Arthropterygius spp. within Ophthalmosaurinae. Thus, the lineage of Nannopterygius was among several ophthalmosaurine lineages that crossed the Jurassic–Cretaceous boundary and, similarly to Arthropterygius , survived the Jurassic–Cretaceous transition at high latitudes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. The giant pliosaurid that wasn't--revising the marine reptiles from the Kimmeridgian, Upper Jurassic, of Krzyżanowice, Poland.
- Author
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MADZIA, DANIEL, SZCZYGIELSKI, TOMASZ, and WOLNIEWICZ, ANDRZEJ S.
- Subjects
REPTILES ,MARINE animals ,TURTLES - Abstract
Marine reptiles from the Upper Jurassic of Central Europe are rare and often fragmentary, which hinders their precise taxonomic identification and their placement in a palaeobiogeographic context. Recent fieldwork in the Kimmeridgian of Krzyżanowice, Poland, a locality known from turtle remains originally discovered in the 1960s, has reportedly provided additional fossils thought to indicate the presence of a more diverse marine reptile assemblage, including giant pliosaurids, plesiosauroids, and thalattosuchians. Based on its taxonomic composition, the marine tetrapod fauna from Krzyżanowice was argued to represent part of the "Matyja-Wierzbowski Line"--a newly proposed palaeobiogeographic belt comprising faunal components transitional between those of the Boreal and Mediterranean marine provinces. Here, we provide a detailed re-description of the marine reptile material from Krzyżanowice and reassess its taxonomy. The turtle remains are proposed to represent a "plesiochelyid" thalassochelydian (Craspedochelys? sp.) and the plesiosauroid vertebral centrum likely belongs to a cryptoclidid. However, qualitative assessment and quantitative analysis of the jaws originally referred to the colossal pliosaurid Pliosaurus clearly demonstrate a metriorhynchid thalattosuchian affinity. Furthermore, these metriorhynchid jaws were likely found at a different, currently indeterminate, locality. A tooth crown previously identified as belonging to the thalattosuchian Machimosaurus is here considered to represent an indeterminate vertebrate. The revised taxonomy of the marine reptiles from Krzyżanowice, as well as the uncertain provenance of the metriorhynchid specimen reported from the locality, cast doubt on the palaeobiogeographic significance of the assemblage. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
33. EVIDENCE OF OPPORTUNISTIC FEEDING BETWEEN ICHTHYOSAURS AND THE OLDEST OCCURRENCE OF THE HEXANCHID SHARK NOTIDANODON FROM THE UPPER JURASSIC OF NORTHERN ITALY.
- Author
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SERAFINI, GIOVANNI, AMALFITANO, JACOPO, COBIANCHI, MIRIAM, FORNACIARI, BEATRICE, MAXWELL, ERIN E., PAPAZZONI, CESARE ANDREA, ROGHI, GUIDO, and GIUSBERTI, LUCA
- Subjects
- *
SPINE , *FOSSIL reptiles , *SHARKS , *OCEAN bottom , *ANIMAL feeding , *CHONDRICHTHYES - Abstract
In 2016, two fossil marine reptiles were re-discovered in the collections of the Museo Civico di Storia Naturale di Verona. Originally recovered near Asiago, Vicenza province (northern Italy) from an outcrop of the Rosso Ammonitico Veronese Fm. (Middle-Upper Jurassic), they were never described. Morphological analysis carried out under UV-light allowed enhancing contrast with the surrounding matrix and better identifying some anatomical details. Both specimens consist of partially articulated postcranial elements from two distinct ichthyosaurs, including vertebrae, ribs, and some fragmentary elements of the appendicular skeleton. The first specimen V7101 is here tentatively assigned to Ophthalmosauridae based on a combination of features shared with other taxa in this family, such as the regionalization of the vertebral column. Taphonomical analysis suggests a long exposure of the carcass on the sea floor before burial; two teeth of the hexanchiform shark Notidanodon found near the ribcage could indicate scavenging. An ichthyosaur tooth most probably not belonging to the same specimen was found stuck on a rib and can also be attributed to scavenging - the first ever record of this interaction between two ichthyosaurs. The second specimen V7102 is represented by a poorly preserved partial vertebral column and is here referred to Ichthyosauria indet. due to the absence of taxonomically significant characters. Calcareous nannofossil data and microfacies analyses allow us to assign both specimens to the basal Kimmeridgian. This makes the two Notidanodon teeth associated with V7101 the oldest recorded occurrence of this genus. [ABSTRACT FROM AUTHOR]
- Published
- 2020
34. Move, burrow, feed – repeat! A compound trace fossil from the Solnhofen Plattenkalke possibly made by holothurians.
- Author
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Vallon, Lothar H., Rindsberg, Andrew K., Röper, Martin, Rothgaenger, Monika, and Rothgaenger, Klaus
- Subjects
- *
TRACE fossils , *ANIMAL feeds - Abstract
Bromlichnus bromleyi n.igen. n.isp., a compound trace fossil consisting of two segments representing dwelling and feeding, is described. Owing to a concentric spreite in a bow-shaped burrow, B. bromleyi is interpreted as made by holothurians. In most cases, it is connected to a repichnion. The new ichnotaxon derives from the narrow Pfalzpaint Subbasin of the Solnhofen archipelago (Upper Jurassic, SE Germany), interpreted as a tidal channel connecting two basins. The interrelationships of different behaviours reflected in compound trace fossils allow holistic analysis of the work of individual animals, enabling more accurate interpretation of tracemaker anatomy and function. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. Re-evaluation of pachycormid fishes from the Late Jurassic of Southwestern Germany.
- Author
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MAXWELL, ERIN E., LAMBERS, PAUL H., LÓPEZ-ARBARELLO, ADRIANA, and SCHWEIGERT, GÜNTER
- Subjects
- *
FOSSIL vertebrates , *FISHES , *RARE fishes , *FOSSILS , *BODY size , *FISH morphology , *FISH anatomy - Abstract
Pachycormidae is an extinct group of Mesozoic fishes that exhibits extensive body size and shape disparity. The Late Jurassic record of the group is dominated by fossils from the lithographic limestone of Bavaria, Germany that, although complete and articulated, are not well characterized anatomically. In addition, stratigraphic and geographical provenance are often only approximately known, making these taxa difficult to place in a global biogeographical context. In contrast, the late Kimmeridgian Nusplingen Plattenkalk of Baden-Württemberg is a well-constrained locality yielding hundreds of exceptionally preserved and prepared vertebrate fossils. Pachycormid fishes are rare, but these finds have the potential to broaden our understanding of anatomical variation within this group, as well as provide new information regarding the trophic complexity of the Nusplingen lagoonal ecosystem. Here, we review the fossil record of Pachycormidae from Nusplingen, including one fragmentary and two relatively complete skulls, a largely complete fish, and a fragment of a caudal fin. These finds can be referred to three taxa: Orthocormus sp., Hypsocormus posterodorsalis sp. nov., and Simocormus macrolepidotus gen. et sp. nov. The latter taxon was erected to replace “Hypsocormus” macrodon, here considered to be a nomen dubium. Hypsocormus posterodorsalis is known only from Nusplingen, and is characterized by teeth lacking apicobasal ridging at the bases, a dorsal fin positioned opposite the anterior edge of the anal fin, and a hypural plate consisting of a fused parhypural and hypurals. The holotype specimen contributes additional palaeobiological information, with small teleosteans preserved as gastric contents and ribs showing signs of callus formation. These new findings extend our knowledge of the anatomy and diversity of Pachycormidae, and represent an important first step in understanding factors controlling their distribution and morphological variation in the Late Jurassic of Europe. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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36. Macroevolutionary trends in the genus Torvoneustes (Crocodylomorpha: Metriorhynchidae) and discovery of a giant specimen from the Late Jurassic of Kimmeridge, UK.
- Author
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Young, Mark T, Foffa, Davide, Steel, Lorna, and Etches, Steve
- Subjects
- *
MUSCLES , *CRANIOMETRY , *DENTITION , *TEETH , *JURASSIC Period , *HYPOGLOSSAL nerve , *OCCIPITAL bone - Abstract
The metriorhynchid crocodylomorph fauna of the Late Jurassic Kimmeridge Clay Formation (KCF) of the UK was highly diverse. One genus from this Formation, Torvoneustes , was unique in evolving dentition similar to known chelonivorous crocodylomorphs and enlarged attachment sites for the pterygoideus adductor musculature. Here we report the largest known Torvoneustes specimen, the occipital region of a large cranium that was discovered on the shore of Brandy Bay, Dorset, UK (KCF). We also report three tooth crowns discovered during the 19th century from Oxfordshire that can also be referred to Torvoneustes. The partial braincase is unique in having: verticalized basioccipital tuberosities that have thickened ventral margins, the notch between the basioccipital tuberosities is a narrow inverted 'U'-shape and a subrectangular-shaped carotid canal foramina. The presence of 'occipital fossae' (deep concavities with the hypoglossal foramina in their dorsomedial corners) and carotid foramina with raised rims relative to the basioccipital posterior surface, allow us to refer it to Torvoneustes. Although incomplete, the exceptional size of the specimen demonstrates that Torvoneustes attained larger body lengths than previously supposed (3.7–4.7 m). Comparing the dimensions of this specimen to other metriorhynchids suggests that at least some Torvoneustes specimens rivalled Plesiosuchus manselii in body length. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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37. Jurassic Radiolarians and Foraminifers from Vorobyovy Gory in Moscow.
- Author
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Palechek, T. N. and Ustinova, M. A.
- Subjects
- *
FORAMINIFERA , *DRILL cores - Abstract
Oxfordian radiolarians from core of boreholes drilled on Vorobyovy Gory (Moscow), from the Podosinki Subformation of the Chulkovo Formation (upper Callovian–lower Oxfordian), Podmoskovnaya Formation (middle–upper Oxfordian), Kolomenskoe Series (upper Oxfordian), and Makariev Formation (upper Oxfordian–lower Kimmeridgian) are studied for the first time. The studied radiolarian assemblages belong to the southern boreal type. Foraminifers were studied alongside the radiolarians. The foraminiferal Lenticulina cultratiformis–Lenticulina pseudocrassa Zone is recognized in the middle Callovian, and the Opthalmidium strumosum–Lenticulina brestica and Lenticulina russiensis–Epistomina uhligi zones are recognized in the Oxfordian. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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38. Tracking Late Jurassic ornithopods in the Lusitanian Basin of Portugal: Ichnotaxonomic implications.
- Author
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CASTANERA, DIEGO, SILVA, BRUNO C., SANTOS, VANDA F., MALAFAIA, ELISABETE, and BELVEDERE, MATTEO
- Subjects
GEOLOGICAL formations - Abstract
The Sociedade de História Natural in Torres Vedras, Portugal houses an extensive collection of as yet undescribed dinosaur tracks with ornithopod affinities. They have been collected from different Late Jurassic (Kimmeridgian--Tithonian) geological formations (Praia de Amoreira-Porto Novo, Alcobaça, Sobral, and Freixial) that outcrop along the Portuguese coast, and belong to two different sub-basins of the Lusitanian Basin (the Consolação and Turcifal sub-basins). Three main morphotypes can be distinguished on the basis of size, mesaxony and the morphology of the metatarsophalangeal pad impression. The minute to small-sized morphotype is similar to the Anomoepus-like tracks identified in other Late Jurassic areas. The small to medium-sized morphotype resembles the Late Jurassic--Early Cretaceous ichnotaxon Dinehichnus, already known in the Lusitanian Basin. Interestingly, these two morphotypes can be distinguished qualitatively (slightly different size, metatarsophalangeal pad impression and digit morphology) but are nevertheless difficult to discriminate by quantitatively analysing their length-width ratio and mesaxony. The third morphotype is considered a large ornithopod footprint belonging to the ichnofamily Iguanodontipodidae. This ichnofamily is typical for Cretaceous tracksites but the new material suggests that it might also be present in the Late Jurassic. The three morphotypes show a negative correlation between size and mesaxony, so the smaller tracks show the stronger mesaxony, and the larger ones weaker mesaxony. The Upper Jurassic ornithopod record from the Lusitanian Basin has yielded both small and medium-sized ornithopod remains, mainly iguanodontians such as dryosaurids and ankylopollexians, which are the main candidates to be the trackmakers. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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39. A Late Jurassic (Kimmeridgian–early Tithonian) fish fauna of the Eperkés-hegy (Olaszfalu, Bakony Mts., Hungary): the oldest record of Notidanodon Cappetta, 1975 and a short revision of Mesozoic Hexanchidae.
- Author
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Szabó, Márton
- Abstract
The first results of the investigation of the Late Jurassic (Kimmeridgian–early Tithonian) fish fauna from the fossil-rich Pálihálás Limestone Formation ("Long trench", Eperkés-hegy, Olaszfalu, Hungary) are detailed here. The present study provides the first systematic faunal data of a Jurassic marine fish community from the Transdanubian Mountains. The low-diversity neoselachian fauna includes Notidanodon sp., Sphenodus sp., and indeterminate synechodontiform, possible indeterminate scyliorhinids, and further, yet indeterminate forms. Actinopterygians are represented by Caturus sp. and indeterminate actinopterygian teeth and scales. The Olaszfalu hexanchid is the most similar to Notidanodon lanceolatus; however, specific determination is not possible. The Olaszfalu record is the second Jurassic (and also the earliest) report of the genus Notidanodon, which re-dates the earliest occurrence of Hexanchidae back into the boundary of the Kimmeridgian–early Tithonian. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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40. A new genus of Pycnodontidae (Actinopterygii) from the Upper Jurassic of France and Germany, included in a phylogeny of Pycnodontiformes.
- Author
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Ebert, Martin
- Subjects
- *
ACTINOPTERYGII , *PHYLOGENY , *INCISORS , *FOSSIL fishes , *TEETH - Abstract
The new genus Thiollierepycnodus is erected here to accommodate ' Gyrodus ' wagneri or ' Proscinetes ' wagneri , a taxon known since the 19th century from the marine Kimmeridgian Plattenkalk of Cerin (France) and since 2014 at the excavation site of the Naturkunde-Museum Bamberg in Wattendorf (Germany). Thiollierepycnodus is placed in Pycnodontidae (Upper Jurassic to Eocene), which is the most advanced family of Pycnodontiformes. With 154–152 Myr (Upper Jurassic), Thiollierepycnodus belongs to the stratigraphically oldest Pycnodontidae, still possessing some primitive features such as four incisiform teeth in the dentary, a crown of bifurcated anterior dentary teeth, reduced scale bars posterior to the dorsal fin origin, but the area of pterygiophores without scales and nine to 10 postanal ventral keel scales and approximately 10 complete scale rows posterior to the cloaca. A phylogenetic analysis leads to the placement of this taxon in Proscinetinae. This and the introduction of two additional taxa from the Cretaceous of Lebanon in the phylogeny are further steps to enlighten the broader evolutionary patterns of Pycnodontidae. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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41. Diversity Patterns of Late Jurassic Chondrichthyans: New Insights from a Historically Collected Hybodontiform Tooth Assemblage from Poland
- Author
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Sebastian Stumpf, Stefan Meng, and Jürgen Kriwet
- Subjects
Chondrichthyes ,Hybodontiformes ,diversity ,biogeography ,Kimmeridgian ,Late Jurassic ,Biology (General) ,QH301-705.5 - Abstract
Here, we provide a detailed taxonomic reassessment of a historically collected chondrichthyan dental assemblage from the lower Kimmeridgian of Czarnogłowy in north-western Poland and discuss its significance for better understanding hybodontiform diversity patterns prior to their post-Jurassic decline in fully marine environments. In spite of its low taxonomic diversity, consisting of four large-toothed taxa (viz., Strophodus udulfensis, Asteracanthus ornatissimus, Planohybodus sp. and cf. Meristodonoides sp.), this assemblage is remarkable in that there are only very few Mesozoic hybodontiform assemblages with more large-toothed genera or even species. Comparisons with other European Late Jurassic hybodontiform-bearing localities demonstrate fairly homogenous distribution patterns characterized by large-bodied epipelagic forms of high dispersal ability. This is in stark contrast to post-Jurassic hybodontiform associations, which are dominated by smaller species that were predominantly bound to marginal marine and continental waters, suggesting a major reorganization of chondrichthyan communities during the Early Cretaceous.
- Published
- 2022
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42. Revision of the Late Jurassic deep-water teleosauroid crocodylomorph Teleosaurus megarhinus Hulke, 1871 and evidence of pelagic adaptations in Teleosauroidea
- Author
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Davide Foffa, Michela M. Johnson, Mark T. Young, Lorna Steel, and Stephen L. Brusatte
- Subjects
Crocodylomorpha ,Teleosauroidea ,Kimmeridgian ,Aquatic adaptations ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Teleosauroids were a successful group of semi-aquatic crocodylomorphs that were an integral part of coastal marine/lagoonal faunas during the Jurassic. Their fossil record suggests that the group declined in diversity and abundance in deep water deposits during the Late Jurassic. One of the few known teleosauroid species from the deeper water horizons of the well-known Kimmeridge Clay Formation is ‘Teleosaurus’ megarhinus Hulke, 1871, a poorly studied, gracile longirostrine form. The holotype is an incomplete snout from the Aulacostephanus autissiodorensis Sub-Boreal ammonite Zone of Kimmeridge, England. The only other referred specimen is an almost complete skull from the slightly older A. eudoxus Sub-Boreal ammonite Zone of Quercy, France. Recently, the validity of this species has been called into question. Here we re-describe the holotype as well as the referred French specimen and another incomplete teleosauroid, DORCM G.05067i-v (an anterior rostrum with three osteoderms and an isolated tooth crown), from the same horizon and locality as the holotype. We demonstrate that all specimens are referable to ‘Teleosaurus’ megarhinus and that the species is indeed a valid taxon, which we assign to a new monotypic genus, Bathysuchus. In our phylogenetic analysis, the latest iteration of the ongoing Crocodylomorph SuperMatrix Project, Bathysuchus megarhinus is found as sister taxon to Aeolodon priscus within a subclade containing Mycterosuchus nasutus and Teleosaurus cadomensis. Notably Bathysuchus has an extreme reduction in dermatocranial ornamentation and osteoderm size, thickness and ornamentation. These features are mirrored in Aeolodon priscus, a species with a well-preserved post-cranial skeleton and a similar shallow and inconspicuous dermal ornamentation. Based on these morphological features, and sedimentological evidence, we hypothesise that the Bathysuchus + Aeolodon clade is the first known teleosauroid lineage that evolved a more pelagic lifestyle.
- Published
- 2019
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43. New erymid lobsters from the Nusplingen and Usseltal formations (Upper Jurassic) of southwest Germany.
- Author
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SCHWEIGERT, Günter and HÄRER, Jürgen
- Subjects
LOBSTERS ,PREDATION ,LAGOONS ,DECAPODA ,SPECIES - Abstract
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- Published
- 2020
- Full Text
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44. Heterobranchia (Gastropoda) from the Jurassic Deposits of Russia.
- Author
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Guzhov, A. V.
- Abstract
Small gastropods from the Jurassic deposits of the European Russia, united into the lower Heterobranchia or Allogastropoda, are described. The families of Ampezzanildidae, Cimidae, Cornirostridae, Ebalidae, and Stuoraxidae are distinguished, and a set of taxa is given without reference to a definite family. The family Ampezzanildidae from the Jurassic deposits is described for the first time on the basis of the mass material, ascribed to the new genus Zizipupa gen. nov. with the sole species of Z. costata sp. nov. The family Cimidae includes the genera of Cristalloella, Rotfanella, Urlocella, and Unzhispira gen. nov. with species C. spiralocostata (Gründel, 1998), R. gerasimovi sp. nov., R. reticulata sp. nov., Urlocella undulata sp. nov., and Unzhispira minuta sp. nov. The genus Heteronatica gen. nov. is included into the family Cornirostridae. This genus is the first siphonostomatous representative of the given family including the sole long-living species H. globosa sp. nov., which is subdivided into subspecies H. globosa globosa and H. globosapromota subsp. nov. The family Ebalidae is represented by the genus Ebala, shells of which are distributed from the Middle Oxfordian to the Middle Volgian. The family Stuoraxidae is described based on two genera Stuoraxis and Aneudaronia gen. nov., including species of S. crassa sp. nov. and A. elegans sp. nov. The genus Doggerostra, which fits into different families of Heterobranchia in terms of shell morphology is represented by the species D. riedeli Gründel, 1998, which was previously known from the Bathonian and Callowian deposits in Poland and Germany, as well as form the Upper Jurassic interval in the Russian Plate. The Middle Volgian subspecies D. riedeli affinis subsp. nov. is distinguished in the composition of this species. In addition, the genus Masaevia gen. nov. with the sole species of M. sinistra sp. nov. is described. Due to so specific shell morphology of this genus, its position in the Heterobranchia system is unclear. It is not improbable that we deal with small planktonic gastropods of protoconchs of unknown group of planktonic or benthic gastropods. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
45. New Data on Jurassic Cerithiopsidae (Gastropoda) from European Russia.
- Author
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Guzhov, A. V.
- Abstract
The Oxfordian–Kimmeridgian Cerithiopsidae, represented by two genera Cosmocerithium Cossmann, 1906 and Dragonia gen. nov. are re-investigated. Three species (C. renardi (Rouillier, 1849), C. pumilum (Gerasimov, 1992), and C. veliger sp. nov.), representing the same phylogenetic line, are distinguished in the genus Cosmocerithium. These species formed during the gradual morphological evolution, traced from the Middle Oxfordian to Early Kimmeridgian. The diagnosis of all Cosmocerithium species was revised and improved. As a result, the species C. contiae Guzhov, 2002 was included into synonymy of C. pumilum. Two new species are described in the composition of Dragonia: D. minuta sp. nov. (index species) and D. longa sp. nov. It is proposed that Cosmocerithium species were necrophages. It was revealed that Dragoniaminuta belongs to assemblages, which inhabited sunken wood and was able to bore wood fragments. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. Sedimentary evolution of a shallow carbonate ramp (Kimmeridgian, NE Spain): Unravelling controlling factors for facies heterogeneities at reservoir scale.
- Author
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Sequero, Cristina, Aurell, Marcos, and Bádenas, Beatriz
- Subjects
- *
CARBONATES , *CARBONATE reservoirs , *HYDROCARBON reservoirs , *RESERVOIRS , *FACIES , *BIOLOGICAL evolution , *CORAL reefs & islands - Abstract
The facies evolution of a Late Jurassic (latest Kimmeridgian) shallow carbonate ramp was reconstructed after the analysis and correlation of 21 logs in a 20 × 30 km outcrop area located south of Zaragoza (northeast Spain). The studied succession belongs to the Higueruelas Formation, which is of potential use as an analogue for understanding facies heterogeneities in certain hydrocarbon carbonate reservoirs (e.g. the Arab Formation, Persian Gulf). The studied succession is arranged in nine sedimentary units bounded by discontinuity surfaces that can be traced over kilometres. Facies analysis permitted the reconstruction of two sedimentary models showing the transition from inner ramp subenvironments (i.e. intertidal, lagoon, backshoal/washover, shoal-sand blanket) to the mid-ramp foreshoal and offshore domains: an oncolitic-peloidal-oolitic and an oolitic-peloidal-dominated ramp. The oncolitic-peloidal-oolitic-dominated ramp is characterized by peloidal-oolitic and oncolitic-dominated shoal-sand blankets that developed in higher-energy inner areas, protecting peloidal-oolitic backshoal and oncolitic lagoon domains including a mosaic of stromatoporoid carpets. Peloidal facies with fenestral porosity accumulated in an intertidal belt or as patches on top of the shoal-sand blankets and washover deposits. Offshore from the shoal-sand blankets, chaetetid/stromatoporoid/coral-rich buildups grew on the more proximal mid-ramp, surrounded by peloidal and peloidal-bioclastic grain- to mud-supported facies. An oolitic-peloidal-dominated ramp developed in a second stage of the evolution of the platform, characterized by the presence of a wide restricted peloidal-bioclastic-oolitic lagoon on the inner ramp grading into a backshoal area dominated by storm-related intraclastic-peloidal deposits. Stromatoporoid carpets disappeared and oncolitic-dominated deposits were constrained to the foreshoal and backshoal domains, and locally to local ponds that developed in the intertidal belt or the restricted lagoon. Internal and external factors controlling facies heterogeneity and the sedimentary evolution of the carbonate ramp include resedimentation, topographic relief, and long- to short-term sea-level fluctuations. • Complexity in spatial facies distribution for a late Kimmeridgian shallow carbonate ramp. • Sedimentary models based on the relative abundance of non-skeletal components. • Internal processes and external factors controlling facies heterogeneities and their evolution. • The proposed sedimentary models can be useful in carbonate reservoir characterization. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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47. Testing carbonate chemostratigraphy across differentiated ancient shallow-platform environments (Early Kimmeridgian, S Iberia).
- Author
-
Coimbra, Rute, Marques, Beatriz, and Olóriz, Federico
- Abstract
Shallow-platform settings with marked differences in paleoplatform bottom physiography influence the degree of connection with oceanic waters and overall circulation patterns, even when sharing the same palaeoclimatic conditions. Two Kimmeridgian shallow-marine settings have been explored to test the sensitivity and reliability of carbonate chemostratigraphy to detect such differences. An integrated overview of the obtained elemental trends depicted four major facies, shared along specific stratigraphic intervals of both depositional records. Diagenesis obliterated original geochemical signals only throughout the siliciclastics-rich interval, corresponding to the most landward setting. For the remaining facies, elemental features could be attributed to the differential action of forcing mechanisms operating along the south-Iberian paleomargin during Kimmeridgian times. The highest degree of continental influence can be recognized by a strong relationship between Fe and Mn for the most proximal setting, which fades out along the mixed carbonate-fine siliciclastic rhythmic deposition in more open settings. A characteristic geochemical signature of progressively more positive δ
13 C values and significantly higher Sr content is identified for the interval dominated by biogenic sponge buildups. Such a local response is related to local forcing by upwelling in the surroundings of a coral fringe. The geochemical signature of a hydrothermal origin can be clearly differentiated from the influence of mere terrigenous pulses. Accordingly, the decoupling of Fe and Mn along marginal settings is the clue to detecting major events of palaeogeographic restructuring. Observed temporal variations in Mg content along both studied sections are attributed to tectonic activity influencing nearshore/coastal water masses. By integrating chemostratigraphic information and complementary evidence, the palaeoenvironmental mechanisms promoting differentiated sedimentary records along ancient subtropical, shallow, coastal settings can be disentangled. Image 1 • Early Kimmeridgian shallow-marine carbonate deposits along southern Iberia. • Contrasting epicontinental settings are tested. • Diagenesis and palaeoenvironmental significance are evaluated. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
48. New contributions to the phylogenetic position of the sauropod Galvesaurus herreroi from the late Kimmeridgian-early Tithonian (Jurassic) of Teruel (Spain).
- Author
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Pérez-Pueyo, M., Moreno-Azanza, M., Barco, J. L., and Canudo, J. I.
- Subjects
PHYLOGENY ,BRACHIOSAURIDAE ,CLADISTIC analysis ,SAURISCHIA - Abstract
Galvesaurus herreroi is a sauropod from the Villar del Arzobispo Formation (late Kimmeridgian-early Tithonian), from the municipality of Galve (Teruel). Its phylogenetic relations have been long debated, so we carried out a phylogenetic analysis, using a new data matrix recently published by Carballido et al. (2017). The characters of Galvesaurus were coded on the basis of the redescription of the published remains and the description of two unpublished fossils: a right coracoid and a fragment of the right pubis. The results of the analysis suggest the inclusion of Galvesaurus in the clade Titanosauriformes, as a sister taxon to Lusotitan, these two taxa form part of the Brachiosauridae clade. Likewise, a stratigraphic study was undertaken, placing the Galvesaurus site in the lower part of the Villar del Arzobispo Formation, thus assigning the sauropod a late Kimmeridgian-early Tithonian age. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
49. The Late Jurassic ray Kimmerobatis etchesi gen. et sp. nov. and the Jurassic radiation of the Batoidea.
- Author
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Underwood, Charlie J. and Claeson, Kerin M.
- Abstract
The laminated marine mudstones of the Late Jurassic of Kimmeridge, southern England, yield two exceptionally well-preserved partial skeletons of a previously unrecognised species of early batoid. These are described as a new genus and species, Kimmerobatis etchesi gen. et sp. nov. which has a general "guitarfish" bauplan as in all other batoids known from the Jurassic. This species possesses a combination of primitive characters such as centra present within the majority of the synarcual and antorbital cartilages that fail to reach the pectoral skeleton along with more derived characters, such as the lack of fin spines. Until now, little study has been carried out on the affinities of Jurassic batoids, despite their key role in understanding batoid evolution. Results from parsimony and likelihood phylogenetic reconstruction indicates that the whole-bodied Jurassic batoids Spathobatis , Belemnobatis , and Kimmerobatis gen. nov. form their own clade, Spathobatidae, and do not lend support to a monophyletic "Rhinobatidae". Among Jurassic batoids, Kimmerobatis gen. nov. is most derived, but with derived characters being independently acquired compared to modern batoids (e.g. presence of a postpelvic process). The inclusion of whole bodied Jurassic fossils have generated a more resolved hypothesis of batoid evolution throughout the Cretaceous and into the Cenozoic. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
50. Correlation of the Kimmeridgian-Tithonian (Jurassic) boundary beds exposed in the Boulonnais, France with those at Kimmeridge, Dorset, UK.
- Author
-
Gallois, Ramues, Vadet, Alain, and Etches, Steve
- Abstract
Abstract Sediments of Kimmeridgian and Tithonian age are well exposed on the Boulonnais coast of northern France between Equihen and Cap Gris Nez and on the south coast of England at and adjacent to Kimmeridge Bay. Both successions were deposited on a marine shelf and lie within the Subboreal faunal province which enables detailed correlations to be made between them based on ammonite assemblages. They are, however, lithologically markedly different due to their environmental settings: close to a land area in the case of the Boulonnais and within a depositional basin in the case of Kimmeridge. The succession adjacent to the Kimmeridgian-Tithonian boundary exposed in the Boulonnais is highly condensed and laterally variable with more attenuated successions occurring close to the former Anglo-Brabant Massif land area. The boundary occurs at the end of a succession of up to six regressive-transgressive events that onlap the land area. This is in contrast to that at outcrop at Kimmeridge, where the Kimmeridgian-Tithonian boundary is marked by a correlative conformity in an unbroken basinal succession. The cliff and foreshore exposures in the Kimmeridge area provide the only unbroken succession in the Subboreal faunal province of the beds adjacent to the Kimmeridgian-Tithonian boundary. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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