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ABSTRACT Drilling predation on echinoids (sea urchins) has been known to occur in marine ecosystems since the Jurassic Period; however, it has rarely been studied in existing species. Tests of the irregular sea urchin Brissus unicolor (Leske, 1778), which frequently occurs in shallow substrates of the Canary Islands, mostly show very evident perforations through their skeletons. The aim of this study was to describe the characteristics of these perforations in order to determine their possible origins as well as document their size, site selectivity, and frequency of occurrence among different sample sites. Of the 104 tests of B. unicolor that were collected from 15 locations off the island of Tenerife (Canary Islands, Spain), 94% showed a least one perforation. These boreholes exhibit a circular morphology, penetrating the sea urchin tests perpendicularly and entirely. Notably, they display a unique acid signature, diverging from those documented in the fossil record and other relevant studies. Our analysis showed size and site selectivity by the predator as the perforations were mainly located on the oral side of the test. The perforations are attributed to drilling predation. The characteristics of these boreholes on B. unicolor match published records of predation marks suggesting that they are produced by the predatory gastropod family Cassidae, with Semicassis undulata (Gmelin, 1791) considered to be the most probable predator. [ABSTRACT FROM AUTHOR]

Background: The Caridea, affiliated with Malacostraca, Decapoda, and Pleocyemata, constitute one of the most significant shrimp groups. They are widely distributed across diverse aquatic habitats worldwide, enriching their evolutionary history. In recent years, considerable attention has been focused on the classification and systematic evolution of Caridea, yet controversies still exist regarding the phylogenetic relationships among families. Methods: Here, the complete mitochondrial genome (mitogenome) sequences of five caridean species, namely Heterocarpus sibogae, Procletes levicarina, Macrobrachium sp., Latreutes anoplonyx, and Atya gabonensis, were determined using second-generation high-throughput sequencing technology. The basic structural characteristics, nucleotide composition, amino acid content, and codon usage bias of their mitogenomes were analyzed. Selection pressure values of protein-coding genes (PCGs) in species within the families Pandalidae, Palaemonidae, and Atyidae were also computed. Phylogenetic trees based on the nucleotide and amino acid sequences of 13 PCGs from 103 caridean species were constructed, and divergence times for various families within Caridea were estimated. Results: The mitogenome of these five caridean species vary in length from 15,782 to 16,420 base pairs, encoding a total of 37 or 38 genes, including 13 PCGs, 2 rRNA genes, and 22 or 23 tRNA genes. Specifically, L. anoplonyx encodes an additional tRNA gene, bringing its total gene count to 38. The base composition of the mitogenomes of these five species exhibited a higher proportion of adenine-thymine (AT) bases. Six start codons and four stop codons were identified across the five species. Analysis of amino acid content and codon usage revealed variations among the five species. Analysis of selective pressure in Pandalidae, Palaemonidae, and Atyidae showed that the Ka/Ks values of PCGs in all three families were less than 1, indicating that purifying selection is influencing on their evolution. Phylogenetic analysis revealed that each family within Caridea is monophyletic. The results of gene rearrangement and phylogenetic analysis demonstrated correlations between these two aspects. Divergence time estimation, supported by fossil records, indicated that the divergence of Caridea species occurred in the Triassic period of the Mesozoic era, with subsequent differentiation into two major lineages during the Jurassic period. Conclusions: This study explored the fundamental characteristics and phylogenetic relationships of mitogenomes within the infraorder Caridea, providing valuable insights into their classification, interspecific evolutionary patterns, and the evolutionary status of various Caridea families. The findings provide essential references for identifying shrimp species and detecting significant gene rearrangements within the Caridea infraorder. [ABSTRACT FROM AUTHOR]

This study introduces new discoveries of fossil footprints from the Middle Jurassic Yaopo Formation in Beijing, China, marking the first reptile fossils that have been discovered in this formation. The two small footprints with parallel digits and drag marks suggest they were made by tetrapods moving through water. While there are similarities to crocodylian and pterosaur tracks, the evaluation suggests that turtles are the most likely trace-makers. If correct, the Yaopo Formation footprints are likely made by xinjiangchelyids, given their dominance in Asian freshwater ecosystems during the Late Jurassic and their widespread distribution in Late Jurassic China. Sichuanchelyids, Bashuchelyidae, and Hongkongochelys are less likely candidates due to their limited temporal and geographical distribution. This finding adds to the growing body of evidence on the evolution and ecology of turtles in Asia during the Late Jurassic period. These new findings offer important insights into the behaviour and spatiotemporal occurrence of these ancient reptiles and expand our understanding of their role in prehistoric aquatic ecosystems. [ABSTRACT FROM AUTHOR]

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing'an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed during the late Early Jurassic period (182.9–177.2 Ma). Their geochemical characteristics and zircon saturation temperatures suggest that the granodiorites are moderately differentiated I-type granites and the monzonitic granite, granodioritic porphyries, and alkali feldspar granites are highly differentiated I-type granites. The degree of magma differentiation progressively increased from granodiorites to alkali feldspar granites. By combining the regional Nd and Hf isotope compositions, it was inferred that the magma source involved the melting of lower crustal material from the Mesoproterozoic to the Neoproterozoic eras. By integrating these findings with contemporaneous intrusive rock spatial variations, it was indicated that the late Early Jurassic granitoids in the Lesser Xing'an–Zhangguangcai Range formed within an extensional tectonic setting after the collision and closure of the Songnen–Zhangguangcai Range and Jiamusi blocks. Additionally, this study constrains the closure of the Mudanjiang Ocean to the late Early Jurassic period (177.2 Ma). [ABSTRACT FROM AUTHOR]

Curved mountain belts are spectacular natural features that contain crucial 3D information about the tectonic evolution of orogenic systems in the absence of other kinematic markers. The Mesozoic units exposed in the Mexican Fold and Thrust Belt in northeastern Mexico show a striking curvature, whose kinematic history has not been studied. The existing tectonic models of the region simply assumed the shape of the tectonic units as an inherent feature to the orogen. We investigated the kinematic history of this curvature through paleomagnetism and rock magnetism analyses, coupled with an exhaustive review of available published literature. The studied data sets indicate a protracted history of (re)magnetizations that occurred during the Late Jurassic‐Paleocene times at least during the Late Jurassic, Cretaceous and early Eocene. More significantly, they show significant counterclockwise rotations in the northern flank of the curvature and moderate clockwise vertical axis rotations along its southern flank. This data set suggests that the Sierra Madre Oriental was a linear belt that experienced oroclinal bending or buckling during the Cretaceous to early Eocene period (120–50 Ma). Plain Language Summary: The geological history of the American Cordillera is complex due to its extensive geological history. We have investigated a section of this Pacific‐Panthalassa region: the remarkable curved sector of the Mexican Fold and Thrust Belt in northeastern Mexico. This winding area, known as the Sierra Madre Oriental, potentially holds important clues about the evolution of the North American crust. To contribute to a better understanding of this area and to complement the scarce geophysical and geological studies, we used the magnetic properties of rocks and reviewed existing published research to investigate. We've uncovered a complex history of rock magnetizations with at least two main events dating back to the Late Jurassic and Cretaceous periods. Our findings also reveal that these mountain ranges were rotated from their original position on vertical axes, suggesting they were originally linear and were bent or buckled during the period from approximately 120 to 50 million years ago. Key Points: With Paleomagnetism we explore the nature of the striking curvature of the Northeastern section of the Mexican Fold‐and‐Thrust BeltOur study shows evidence of Orocline bending or Buckling during the major horizontal crustal shortening event of the Mesozoic in Mexico [ABSTRACT FROM AUTHOR]

Switzerland is an ichthyosaur country: it has a rich record of marine reptile fossils, particularly the fish-shaped ichthyosaurs, and the according research. Here, we provide an overview over the 12 or more genera and at least 13 species plus numerous fragmentary remains of ichthyosaurs from the Triassic to the Cretaceous that have been discovered in twelve cantons thus far, of which four species are based on Swiss holotypes. This wealth of ichthyosaur species can be explained by their abundance in the Middle Triassic conservation deposits (Konservat Lagerstätte) of Monte San Giorgio, as well as occasional discoveries in strata of Middle Triassic to Early Cretaceous age. The moderate abundance of outcrops in reasonable conditions in combination with the long history of palaeontological research in Switzerland explains this good fossil record. In addition to this unique overview, we provide more data for further studies and update the knowledge of these taxa. [ABSTRACT FROM AUTHOR]

Granitoids are known to crop out on ancient seashores, but the related geological evidence remains limited. The information from the Western Caucasus sheds light on the stratigraphical distribution of coarse siliciclastic beds associated with late Carboniferous granitoids of the Dakh, Rafabgo, and Sakhray crystalline massifs. For the purposes of this study, the available information was reviewed and verified against the modern stratigraphical scales. It is established that the considered coarse sisliciclastic beds occur at five stratigraphical levels of the Triassic–Jurassic succession. A rocky seashore with granitoid exposures existed for a short time around the Sakhray and probably Rufabgo massifs at the very beginning of the Triassic. The Dakh Massif possessed such a shore twice (at least), i.e., in the Norian–Rhaetian and the Early Toarcian. However, it cannot be excluded that rocky shores persisted there for >50 Ma. Generally, the Western Caucasus provides an example of granitoid exposures on Mesozoic seashores and adds knowledge of the global distribution of rocky shores in the Triassic and Jurassic periods. [ABSTRACT FROM AUTHOR]

The ∼173–164 Ma Papudo‐Quintero plutonic complex near 32.5°S in central Chile records three deformation events that provide insight into the tectonic development of the early Andean margin. The first event (D1) includes: (a) high‐temperature (>600°C), coaxial‐dominated strain along NE‐ to N‐striking subvertical shear zones; (b) widespread emplacement of granitic dikes that dip gently to steeply NE; and (c) development of narrow (<10 cm thick) strike‐slip and oblique‐reverse shear zones. These D1 structures record NW‐SE to WNW‐ESE transpressional shortening with a component of sinistral shear parallel to the N‐S trending magmatic arc. Zircon and apatite U‐Pb dates and cross‐cutting relations constrain most D1 deformation to ∼166–164 Ma. The second event (D2) occurred during postmagmatic cooling in the Late Jurassic and was characterized by development of pervasive E‐W‐striking veins with alteration halos and minor strike‐slip and normal faults that record N‐S extension in a transtensional regime. Structures associated with the last deformation event (D3) include Late Jurassic to Early Cretaceous mafic dikes, veins, and conjugate strike‐slip faults that record NW‐SE to N‐S shortening in a strike‐slip regime. D1 deformation is consistent with studies from other areas that document NW‐SE shortening ± sinistral transpression along the arc throughout the Jurassic, suggesting this deformation was regional in scale and driven by oblique subduction convergence. Deformation associated with oblique convergence was localized within the active magmatic arc, which was an important process in the early Andean orogeny. As the arc migrated eastward, D2 and D3 structures formed in a low‐stress regime in an arc margin or forearc setting. Key Points: Three deformation events (D1, D2, and D3) are recorded in the ∼173–164 Ma Papudo‐Quintero plutonic complex in central ChileD1 records ductile NW‐SE transpressional shortening in the Middle Jurassic; D2 and D3 record brittle transtension or strike‐slip deformationD1 is consistent with regional oblique subduction convergence and localization of plate‐driven strain in the active magmatic arc [ABSTRACT FROM AUTHOR]

Stegosaurs are a minor but iconic clade of ornithischian dinosaurs, yet due to a poor fossil record, their early evolution is poorly understood. Here, we describe a new stegosaur, Baiyinosaurus baojiensis, gen. et sp. nov. from the Middle Jurassic Wangjiashan Formation of the Pingchuan District, Baiyin City, Gansu Province, China. The frontal of Baiyinosaurus possesses a unique characteristic among Stegosauria: it is wider than long and contributes to both the medial and anterior margins of the supratemporal fenestra. The character combinations of dorsal vertebrae of Baiyinosaurus are also different to other stegosaurs: its neural arches are not greatly elongated, its parapophyses are well developed, and its neural spines are axially expanded in lateral. The features of the frontal and vertebrae of Baiyinosaurus are reminiscent of basally branching thyreophorans, indicating that Baiyinosaurus is transitional in morphology between early thyreophorans and early-diverging stegosaurs. Systematic analysis shows that Baiyinosaurus is an early-diverging stegosaur. [ABSTRACT FROM AUTHOR]

The northern margin of the North China Craton is one of the most important porphyry-skarn molybdenum ore belts in the world. The eastern Hebei Province, which contains a high number of molybdenum and gold (molybdenum) resources, is an important portion of the northern margin of the North China Craton. Xichanggou and Huashi, located in eastern Hebei, are quartz-molybdenum vein deposits that are intimately associated with intrusions that are deeply concealed in the mining area. This work presents two zircon U-Pb dates and ten molybdenite Re-Os ages from samples of the aforementioned two deposits in order to determine the timing of the intrusion and mineralization. The zircon U-Pb ages of the quartz monzonite porphyry from Xichanggou are determined to be 163.3 ± 0.3 Ma and 162.8 ± 0.4 Ma. The molybdenite Re-Os dating yielded ages of 160.3 ± 4.6 Ma for Xichanggou and 171.4 ± 19 Ma for Huashi, respectively. The isotopic composition of oxygen and hydrogen of the ore-forming fluid from Huashi, as indicated by the δDV-SMOW values (−80.0‰ to −67.6‰) and δ18OH2O values (−1.86‰ to 2.33‰), suggests that the fluid is primarily composed of water derived from magma, with some contribution from atmospheric precipitation. The sulfur isotope values (δ34S) of sulfides from Xichanggou range from 6.5‰ to 7.1‰, while the δ34S values from Huashi range from 3.3‰ to 4.9‰. The lead isotope ratios (206Pb/204Pb and 207Pb/204Pb) of sulfides from Xichanggou and Huashi average at 17.414, 15.428, and 17.591, 15.379, respectively. The Re-Os isotopic compositions of ore sulfides mostly fall within the range of 318 ppm to 50,114 ppm. These isotopic compositions indicate that the materials responsible for the formation of the ores in Xichanggou and Huashi primarily originate from the melting of lower crust materials that have been contaminated by the mantle. Based on the regional data, the molybdenum deposits in eastern Hebei were formed in multiple periods, specifically approximately 170 Ma and 160 Ma in Huahsi and Xichanggou, respectively. The subduction of the Paleo-Pacific plate during the middle–late Jurassic period led to the partial remelting of lower crust material, resulting in the acquisition of a significant quantity of metal elements (Mo), which were subsequently deposited. [ABSTRACT FROM AUTHOR]

The South China Block, a region renowned for its extensive granite distribution and rich metal deposits, serves as a natural laboratory for the study of granite-related mineralization. This research focuses on the Tongtianmiao granite pluton, which is located at the intersection of the Qin-Hang and Nanling metallogenic belts and has been confirmed as a significant lithium mineral resource. Despite its discovery and ongoing development, the lithium-rich Tongtianmiao pluton has been understudied, particularly concerning its petrogenesis, which has only recently come to the forefront of scientific inquiry. By integrating an array of petrogeochemical data with geochronological studies derived from zircon and monazite dating, this study provides insights into the magmatic processes related to lithium enrichment in the Tongtianmiao granites. The Tongtianmiao granites are classified as A-type granites characterized by high SiO2 contents (69.18–78.20 wt.%, average = 74.08 wt.%), K2O + Na2O contents (4.59–8.34 wt.%, average = 6.86 wt.%), A/CNK > 1.2, and low concentrations of Ca, Mg, and Fe. These granites are enriched in alkali metals such as Li, Rb, and Cs but are significantly depleted in Ba, Sr, and Eu. They show no significant fractionation of light or heavy rare-earth elements but present characteristic tetrad effects. A finding of this study is the identification of multiple ages from in situ zircon U–Pb dating, which implies a prolonged history of magmatic activity. However, given the high uranium content in zircons, which could render U–Pb ages unreliable, emphasis is placed on the monazite U–Pb ages. These ages cluster at approximately 172.1 ± 1.1 Ma and 167.9 ± 1.6 Ma, indicating a Middle Jurassic period of granite formation. This timing correlates with the retreat of the Pacific subduction plate and the associated NE-trending extensional fault activity, which likely provided favorable conditions for lithium enrichment. The study concluded that the Tongtianmiao granites were formed through partial melting of crustal materials and subsequent underplating by mantle-derived materials, and were contaminated by strata materials. This process resulted in the formation of highly differentiated granite through magmatic differentiation and external forces. These findings have significant implications for understanding the petrogenesis of lithium-rich granites and are expected to inform future exploration endeavors in the Tongtianmiao pluton. [ABSTRACT FROM AUTHOR]

Shallow marine shelf sedimentation is a hot and difficult topic in today's reservoir sedimentology research, and it is widely present in the world. The shallow marine shelf sedimentation is not only affected by complex hydrodynamic effects such as tides and waves, but also controlled by bottom tectonic features, forming a complex and varied sedimentation pattern. During the Middle Jurassic period, the northern part of West Siberian Basin was characterized by a shallow marine shelf sedimentary environment. In the central reion of this basin, a typical tectonic uplift zone developed, forming a tectonic background of "one uplift zone between two depressions". Simultaneously, the dominant influence of tides in the shallow marine shelf environment facilitated the formation of a typical shelf-type tidal delta sedimentation system in the Jurassic strata of the northern part of West Siberian Basin. This sedimentation constitutes a significant natural gas reservoir, and it is important to investigate the sedimentary evolution of shelf-type tidal deltas and to clarify the internal structure and distribution of sedimentary sand bodies and interlayers in shelf-type tidal deltas, which is the basis for the fine development of this type of reservoir. This paper takes the Jurassic strata in the Y region of northern part of West Siberian Basin as the research object, and conducts numerical simulation based on sedimentary dynamics for the shelf-type tidal delta sedimentation formed under the tectonic background of "one uplift zone between two depressions". In addition, tidal amplitude and initial water level were selected for different hydrodynamic factors to study the main controlling factors of shelf-type tidal delta sedimentation. The simulation results show that tidal amplitude is positively correlated with three-dimensional configuration characteristic parameters of the sedimentary sand bodies, and the development of tidal bars becomes more and more limited as the initial water level increases. This paper systematically investigates the sedimentary evolution of shelf-type tidal delta under the tectonic background of "one uplift zone between two depressions" by the sedimentary dynamics method, which deepens the understanding of the shelf-type tidal delta sedimentation process and provides a new thinking for the development of this sedimentary reservoir type (School of Geosciences China University of Petroleum (East China)). [ABSTRACT FROM AUTHOR]

Phylogenetic analyses of planthoppers were conducted using a mitogenome dataset to examine the evolutionary relationships of current families based on both maximum likelihood (ML) and Bayesian inference methods. Delphacoidea, including Cixiidae and Delphacidae, and Fulgoroidea, including all other families, were consistently identified as monophyletic groups. However, Nogodinidae displayed a polyphyletic pattern, with various lineages emerging sister to several issidoid families. Variations were observed across different analyses in the positioning of (Dictyopharidae + Fulgoridae) and the relationships of Ricaniidae sister either to Issidae or to (Flatidae + Acanaloniidae). Several statistical tests indicate that the ML topology has the highest level of statistical confidence. The (Dictyopharidae + Fulgoridae) clade is best positioned as sister to (Derbidae + (Achilidae + (Tropiduchidae + other "higher" planthoppers families))) and the Ricaniidae as sister to (Flatidae + Acanaloniidae). With 13 fossil calibration points, origin times for Delphacoidea and Fulgoroidea were dated back to the Late Permian, approximately 257.46 million years ago. Delphacidae and Cixiidae split during the Late Triassic, while Fulgoroidea diversified earlier during the Middle Triassic. Divergence and diversification times are also provided for all other extant planthopper families. These results suggest that Delphacoidea and Fulgoroidea likely diverged from the older planthopper fossil families prior to the emergence of angiosperms and may have initially fed on gymnosperms and ancient ferns. The diversification of extant planthopper families occurred during the Jurassic and Cretaceous periods, influenced by evolving climatic conditions, the decline in gymnosperms, and the increasing diversity of angiosperm plants. [ABSTRACT FROM AUTHOR]

Summary: We investigated the mining mode of insect feeding, involving larval consumption of a plant's internal tissues, from the Middle Jurassic (165 million years ago) Daohugou locality of Northeastern China. Documentation of mining from the Jurassic Period is virtually unknown, and results from this time interval would address mining evolution during the temporal gap of mine–seed plant diversifications from the previous Late Triassic to the subsequent Early Cretaceous.Plant fossils were examined with standard microscopic procedures for herbivory and used the standard functional feeding group–damage‐type system of categorizing damage. All fossil mines were photographed and databased.We examined 2014 plant specimens, of which 27 occurrences on 14 specimens resulted in eight, new, mine damage types (DTs) present on six genera of bennettitalean, ginkgoalean, and pinalean gymnosperms.Three conclusions emerge from this study. First, these mid‐Mesozoic mines are morphologically conservative and track plant host anatomical structure rather than plant phylogeny. Second, likely insect fabricators of these mines were three basal lineages of polyphagan beetles, four basal lineages of monotrysian moths, and a basal lineage tenthredinoid sawflies. Third, the nutrition hypothesis, indicating that miners had greater access to nutritious, inner tissues of new plant lineages, best explains mine evolution during the mid‐Mesozoic. See also the Commentary on this article by McLoughlin & Santos, 242: 2391–2393. [ABSTRACT FROM AUTHOR]

The U–Pb detrital zircon record of the Surat Basin, an important part of the Great Australian Superbasin, has already revealed important insights about sediment source terranes. However, owing to the high closure temperature of zircons, low-temperature thermal events that might have impacted the sediment are not recorded. Here, new 40Ar/39Ar detrital mica ages, which record low-temperature events as a result of isotopic resetting, are paired with published U–Pb detrital zircon ages from the same samples to provide a more complete interpretation of the tectonic and thermal history of the Jurassic-age Precipice Sandstone and Evergreen Formation. The 40Ar/39Ar geochronology of mica grains from five wells reveals two broad groups with distinct age populations: 1500–180 Ma and 150–45 Ma. Micas older than about 180 Ma are sourced from multiple terranes. The slight discrepancy in ages between the 40Ar/39Ar and the U–Pb systems of the same samples may represent differences in closure temperature. However, some micas, such as those dating to ca 180 Ma, may also reflect a thermal reset event. Similarly, the younger group of micas, split into Cretaceous and Paleogene populations, reflect the impact of post-depositional thermal events on the basin. Isotopic resetting of the micas was likely the result of hydrothermal fluids migrating through reactivated faults, fractures and/or porous and permeable sediments. The origin of the fluids during the Cretaceous can be linked to an eastern subduction zone and subsequent igneous underplating resulting in uplift and denudation. The exact source of the hydrothermal fluids for the micas of Paleogene age, recorded in samples collected from the base of the Evergreen Formation, however, remains uncertain. Importantly, 40Ar/39Ar dating of mica from sandstones permits the detection of post-depositional thermal events that may have implications for tracing fluid migration throughout the basin and reconstructing the Cretaceous–Paleogene tectonic history of the basin. Combining 40Ar/39Ar dating of micas with U–Pb dating of zircons reveals a more complete tectonic and thermal history of the Jurassic-age Precipice Sandstone and Evergreen Formation of the Surat Basin. 40Ar/39Ar dating of detrital micas reveals two broad groups with distinct age populations: 1500–180 Ma and 140–45 Ma. Ages older than ca 180 Ma are linked to multiple source terranes, including the Thomson and New England orogens, and the contemptuous magmatic arc. Ages younger than 150 Ma are most likely the result of post-depositional thermal resetting events, which may have implications for fluid movement throughout the basin. [ABSTRACT FROM AUTHOR]

The Dunhuang Basin, situated in western China along the Altyn Tagh Fault (ATF) zone, intersects the Tethys and Paleo‐Asian Ocean tectonic domains. Influenced by both the ATF system and the far‐field effects of the Qiangtang‐Lhasa‐Eurasia collision during the Mesozoic, the mechanism of the Jurassic sedimentary migration of the basin in response to tectonic movements is unclear so far. The paper uses a comprehensive approach, including field geological surveys, lithologic and lithofacies discern, stratigraphic relationships analysis and 2D seismic profile interpretation, to examine the distribution of Jurassic residual strata in the basin. The comprehensive results of our study suggest that the Dunhuang Basin exists as an isolated block with unique tectonic and sedimentary evolution characteristics. In the Early Jurassic, the Dunhuang Basin underwent initial rifting, leading to the formation of small segmented intermontane sags. This phase was marked by the coarse particle sedimentary system of alluvial fans and braided rivers, represented the near source rapid deposition in the initial formation period of the basin. Stratigraphic distribution was primarily influenced by pre‐Jurassic basement topography and was not significantly constrained by faulting during this period. The formation of these isolated discontinuous small intermontane sags indicates the segmented activities of the ATF in the Early Jurassic period. In the Middle Jurassic period, influenced by the ATF dextral strike‐slip faulting, sedimentation extended eastward and the depocenter migrated clockwise compared with the distribution of the Middle Jurassic strata within the Dunhuang Basin. This period witnessed the development of coal measure strata at the basin's margins and lacustrine fine‐grained clastic deposition in the centre. The segmented fracture of the ATF gradually initiated a unified dextral strike‐slip tectonic movement. In the Late Jurassic period, sedimentary strata were locally present in the Wanyao Sag but absent in other sags. The depocenter migrated counterclockwise compared with the distribution of Middle Jurassic strata within the Dunhuang Basin, due to regional uplift accompanied by the ATF sinistral strike‐slip faulting caused by the collision between the Lhasa Block and the Eurasia Plate. The depocenter migration of the Dunhuang Basin constrained within the ATF system from the Early to Middle and Late Jurassic can be attributed to the transition of the ATF strike‐slip faulting in context of the stress relaxation and compression between the collision of the Qiangtang and Lhasa blocks to the Eurasia Plate, respectively. [ABSTRACT FROM AUTHOR]

The morphology of stony corals (Scleractinia) remains the only means to reconstruct the most inclusive evolutionary history of the clade comprising both extant and extinct species. The definitions of morphological characters and their associated trait states are critical for assembling a dataset that could be analysed for phylogenetic reconstruction. Here, we present coral morphological data that consist of more than a hundred characters reviewed by the Corallosphere working group. These characters would eventually form the basis of a data matrix used to reconstruct the phylogeny of all extinct and extant scleractinian families. The initial results obtained by the working group comprise poorly resolved trees, which are biased by the complexity of the multiple character states and the multiplicity of researchers involved in the coding process. When the analysis is restricted to matrices consisting of families from the Triassic and Jurassic periods and coded by a single person, resolution increased, allowing for further exploration of various ingroups and outgroups. The results presented here represent analyses of (i) a data matrix with all families represented by their type genus; (ii) a data matrix with selected families represented by their solitary or phaceloid genera; (iii) a data matrix with only Triassic corals; (iv) a data matrix with only Jurassic corals; (v) a data matrix with Triassic and Jurassic corals; and (vi) data matrices with several outgroups. Well-resolved trees have been obtained in several cases. Phylogenetic relationships among basal, robust and complex groups established using molecular data are discussed in the context of the morphological phylogeny obtained here. [ABSTRACT FROM AUTHOR]

Upper Toarcian ostracod assemblages from Boca da Mata, Alvaiázere, Central Portugal, are described to complement earlier work on the ostracods of the Toarcian GSSP at Peniche, western Portugal. A total of 44 species are recorded and the following new taxa described: Cytheropterina ainsworthi sp. nov., Eucytherura alvaiazerensis sp. nov., Otocythere iberobritannica sp. nov., Ophektycythere gen. nov. with O. herrrigi sp. nov., O. mataensis sp. nov. and O.? sicoensis sp. nov. The assemblages reflect oxygenated fully marine, sublittoral shallow water conditions in a proximal margin of the Lusitanian Basin. The species spectrum has most in common with material described from Western Europe especially the Fastnet Basin, offshore Ireland. Lowermost Aalenian assemblages contain some Toarcian species but also new taxa not studied in detail. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibetan Plateau experienced a unique geological evolution during the Jurassic, driven by the termination of the Palaeotethys and the reduction of the Neotethys. The Indian Plate separated from the northern margin of Gondwana and drifted northward from the Southern Hemisphere. Given that the timing of strata serves as the basis for reconstructing geological history, the present work aimed to develop a new multiple stratigraphic and chronologic framework for the Jurassic strata of the Qinghai-Tibetan Plateau region via a synthesis of the material on lithostratigraphy, palaeontology, iso-radiometric dating, magnetostratigraphy, and other techniques with an emphasis on recent progress and findings. The new framework included the Jurassic System from the four major subdivisions of the plateau: the Baryan Har, Qiangtang, Lhasa-Gandise, and Southern Xizang (Himalaya). Ultimately, a more complete, refined biostratigraphic sequence was proposed, comprising the most common fossils in the plateau and those that are stratigraphically significant for the Jurassic stratigraphy, including ammonites, bivalves, brachiopods, foraminifera, radiolarians, and dinoflagellate cysts for the marine strata, and pollen and spores, and charophytes for the terrestrial sediments. This biostratigraphic framework was correlated with the Jurassic international standard zonation of the Geological Time Scale 2020 via standard or representative species or genera of ammonites. Based on this framework, we constructed a lateral correlation of the Jurassic strata between different basins of the plateau. The palaeontologic correlation in the present work shows that the Lhasa-Gandise Block had a closer relationship with the Qiangtang Block than with the Southern Xizang Himalaya during the Jurassic Period. Meanwhile, the Lhasa-Gandise Block and Qiangtang Block shared similar marine fauna features of the north marginal East Tethys. This contrasts the opinion suggesting that the Yarlung Zangbo Tethys was a small back-arc basin. A combination of stratigraphical, palaeontological, and sedimentological analyses implies that the Bangong Co-Nujiang Tethys may have begun rifting in the Late Triassic, evolving to the birth at the late Early Jurassic with the formation of ocean crust. However, this resulted in failure after it grew into the climax at the end of the Middle Jurassic when the Qiangtang Block began subducting under the Lhasa-Gandise Block. In the Early Cretaceous, the two blocks finally merged. [ABSTRACT FROM AUTHOR]

The Jenkyns Event (~183 Ma) represents an exceptional warming period in the Jurassic, which is characterized by intense environmental and climate perturbation. The eruption of the Karoo‐Ferrar Large Igneous Province (K‐F LIP) triggered pronounced carbon isotope negative excursion (N‐CIE) in exogenic carbon reservoirs, global widespread organic carbon burial and extensive ocean anoxia. However, the synchronic coupling relationship between the carbon release, volcanic activity, and intense weathering induced by the K‐F LIP during this period remains poorly understood. In this study, detailed sedimentologic and geochemical studies were conducted on the terrestrial stratigraphy of the Lower Jurassic Fuxian Formation in the Ordos Basin. Three spore‐pollen assemblages have been identified, with the Cyathidites‐Deltoidospora‐Chasmatosporites assemblage suggesting a Pliensbachian age, the Classopollis‐Cycadopites‐Chasmatosporites assemblage indicating an early to middle Toarcian age, and the Cyathidites‐Cycadopites‐Psophosphaera assemblage indicating a late Toarcian age. The lower part of the Classopollis‐Cycadopites‐Chasmatosporites assemblage shows a negative CIE with a magnitude of 2.7‰, accompanied by organic carbon enrichment. Mercury concentrations and Hg/total organic carbon ratios also show peaks during the initial stage of the carbon isotope negative shift, implying a synchrony between volcanic activities and carbon perturbation. Furthermore, the Chemical Index of Alteration value has reached its maximum and the kaolinite content shows a sharp increase at the same position as the carbon isotope negative shift initiation, indicating a simultaneous enhancement of continental weathering during volcanic activity. The changing patterns of the continental weathering intensity encompassing the Jenkyns Event also indicate that continental weathering may have functioned as a significant approach to counteract the greenhouse effect caused by substantial volcanic CO2 emissions. [ABSTRACT FROM AUTHOR]

Hsisosuchus, with three known species, was the most common genus of crocodyliforms in the Sichuan Basin during the Jurassic. However, the overall shape of the ventral trunk shield of osteoderms has not been clarified due to the lack of complete specimens. A new specimen of Hsisosuchus recently recovered from the Upper Jurassic of Yunnan has the nearly complete ventral trunk shield preserved. This specimen provides an example for the first time for us to understand the shape and the way of the arrangement of the osteoderms in the ventral trunk shield in the genus. Compared with the articulated part of the ventral trunk shield preserved in two of the three species of the genus, the osteoderms of the ventral trunk shield of the new specimen are different in both shape and way of arrangement, indicating that the pattern of the ventral trunk shield is not constant within Hsisosuchus. With no skull and much of the postcranial skeleton poorly preserved as well as no corresponding element that can be used to compare with all the three species, the new specimen was considered as an indeterminate species of Hsisosuchus, awaiting more materials to clarify the problem. [ABSTRACT FROM AUTHOR]

The Jurassic Period was a significant phase of variable organic matter accumulation in paleo-shelf areas of the southern Tethys (Egypt). Reconstructing the paleoredox conditions, paleoclimate, and weathering intensity, along with the role of terrigenous sediment flux and mineralogical maturity, is important for understanding basin infill history and prevalent paleoenvironmental conditions. Here, inorganic geochemical data are presented from the Middle Jurassic Khatatba Formation and two samples from the underlying Ras Qattara and the overlying Masajid formations in the Jana-1x well, Shushan Basin, Western Desert. Twenty-four (24) whole-rock samples were analyzed for their major and trace element composition and carbonate content. The Khatatba Formation represents one of the major hydrocarbon source rocks in the North Western Desert, Egypt. Redox conditions were assessed based on enrichment factors of redox-sensitive elements Mo, V, U, and Co. Results revealed that the Khatatba Formation was deposited under predominant anoxic bottom and pore water conditions, in contrast to the oxic settings that were prevalent during the deposition of the Ras Qattara and Masajid formations. Continental weathering intensity and paleoclimate were reconstructed based on several proxies, such as the chemical index of alteration (CIA), K2O/Rb, Rb/Sr, Ln(Al2O3/Na2O), and Al/K ratios, indicating that the studied succession was deposited during alternating phases between weak and moderate weathering intensity under arid and warm-humid climates, respectively. Periods of enhanced continental weathering were associated with high values of clastic ratios such as Si/Al, Ti/Al, and Zr/Al, suggesting increased terrigenous sediment supply during intensified hydrological cycling. These ratios further provided inferences about the changes in sediment grain size, such as a change from shale to coarse silt- and sand-size fractions. [ABSTRACT FROM AUTHOR]

A small tonalite – dacite body has been discovered in the Nakanogawa Group, Hidaka Belt, northern Japan, which is a Palaeogene subduction complex formed in the palaeo-Japan trench along the northeastern margin of Eurasia. The tonalites are characterized by extremely low K2O (0.2–0.3 wt.%) and relatively flat chondrite-normalized rare earth element patterns (La/Yb[N] ~2.3), similar to plagiogranites in ophiolites. The major-and trace-element characteristics are consistent with low-pressure partial melting of oceanic crust outside the garnet stability field. Zircon U – Pb dating of the tonalite yielded a weighted-mean 206Pb/238U age of 159.1 ± 1.6 Ma. Late Jurassic oceanic plateau-type basaltic rocks with a small amount of plagiogranitic rocks are distributed sporadically in subduction complexes along the palaeo-Japan arc – trench system. A similar zircon U – Pb age (151.6 ± 1.8 Ma) has been reported for greenstone in the Cretaceous subduction complex along the palaeo-Kuril arc – trench system. The tonalite – dacite block was probably derived from the subduction complex at the junction of the palaeo-Japan and -Kuril arc – trench systems. Thus, the greenstones and the tonalite body were likely part of a large oceanic plateau, which formed at the Izanagi – Pacific–Farallon ridge triple junction during the Late Jurassic – Early Cretaceous. [ABSTRACT FROM AUTHOR]

he article discusses the Upper Jurassic Galice Formation in the Western Klamath Mountains, focusing on its formation within an intra-arc basin during the Nevadan orogeny, and how new detrital zircon U-Pb age analyses provide insights into its provenance and age range. Topics include the complex provenance of the Galice Formation, inferred sediment transport pathways, and implications for tectonic models of the Nevadan orogeny.

More than 60% of the world's sedimentary rocks are mudrocks (Potter et al., 1980; Schieber, 1998; Potter, 2003; the term mudrock is favored here over mudstone because the latter term was used to characterize a limestone texture; Dunham, 1962). From a palaeontological perspective these are, compared to sandstones and limestones, heavily undersampled. The main reason for this is that mudrocks decay in surface exposures to small chips, which develop with sun/heat and rain into an awkward pulp. The decay of the mudstone concomitantly destroys all macrofossils which are not durable. This comprises fossils with an aragonitic or delicate calcitic shell unless they are preserved as pyritic or internal calcitic molds or preserved within calcareous concretions. Therefore, most of the fossils are not recorded in surface exposures. In addition, sedimentologic investigations of mudrocks are hampered because (i) compaction makes sedimentary structures hardly recognizableand (ii) good thin sections of mudrocks are exceedingly difficult to manufacture. For micropalaeontological investigations, mudrocks rich in organic material are especially difficult to process. Standard treatments with boiling water, sodium carbonate solution, or peroxide H2O2 generally fail to dissolve much of the sediment so that the fine fraction (and in mudrocks we usually need the 63μm-fraction) largely consists of clay particle aggregates. Yet there are methods to dissolve these aggregates. Otherwise, picking the microfossils would become extremely laborious. In this paper, some guidelines for successful palaeontological work in mudrocks are outlined. These are based on the author's personal experience. Examples from Jurassic mudrocks of Switzerland/Europe show that such excavations can be very rewarding. [ABSTRACT FROM AUTHOR]

Frequent wildfires associated with emplacement of the Central Atlantic Magmatic Province (CAMP) are thought to have been important drivers of two significant changes in terrestrial plant communities and diversity during the Triassic-Jurassic Mass Extinction (TJME, ca. 201.51 Ma). However, it remains to be investigated whether these two changes are potentially related to different wildfire types. To better understand this relationship, we used a new method to reanalyze fossil pollen and spores across the Triassic-Jurassic transition in the Jiyuan Basin from the North China Plate. Results show that two peaks in wildfire frequency experienced different types of wildfires, with each linked to significant changes in plant communities and diversity losses. In the first wildfire peak, canopy fires dominated and are accompanied by significant losses of canopy forming plants, while in the second wildfire peak, ground cover fires dominated accompanied by significant losses of ground cover plants. Changes in atmospheric humidity conditions were an important control on the two different wildfire peaks. Relatively humid climatic conditions corresponded to the prevalence of canopy fires and hindered the spread and development of ground cover fires in wet surface conditions. Conversely, relatively arid climatic conditions corresponded with the prevalence of ground cover fires in dry surface environments. Our results provide a potential relationship between terrestrial plant communities and wildfire types, which is important to further understanding of terrestrial environmental and floral changes driven by Large Igneous Provinces. [ABSTRACT FROM AUTHOR]

Although the study of extinct species is crucial for diversification and evolutionary history of Hymenoptera, the past diversity of Liadoxyelini (Xyelidae, Xyelinae) is relatively poorly documented. Herein, one new fossil genus with one species, Novoxyela bella gen. et sp. nov., and one species, Platyxyela elegans sp. nov., are described and figured from the Middle Jurassic Daohugou Beds of Inner Mongolia, China. N. bella gen. et sp. nov. differs from other Liadoxyelini by combination of traits including unusual large head, pterostigma only sclerotised basally, 1-Rs almost as long as 1-M and 1 m-cu slightly shorter than 2-Cu. P. elegans sp. nov. exhibits unique features hitherto unknown among species of the Platyxyela, viz., pterostigma of medium width, completely sclerotised and ovipositor sheaths widest subapically. The diversity of known fossil species of Liadoxyelini and new forewing characters, as well as a new key to species of Platyxyela, are presented. LSIDurn:lsid:zoobank.org:pub:874C3A78-2EA3-4877-AA5E-AC352A8AFCAE [ABSTRACT FROM AUTHOR]

Remarkably well-preserved crustal sections from the Eastern Hellenides offer the chance to evaluate the regional geodynamic evolution of continental crust. Here, we identify and geodynamically interpret eclogite facies metamorphism in the Triassic–Jurassic volcano-sedimentary series of the West Circum Rhodope zone in the eastern Hellenides. Equilibrium phase diagrams and measured mineral compositions were used to inform reconstructions of geodynamic evolution during the early Alpine period. We newly define the existence of the Eohellenic HP belt, consisting of pre-Alpine basement, continental volcano-sedimentary formations, and a Jurassic magmatic arc. We suggest that the Eohellenic HP-Belt was subducted in the late Jurassic to early Cretaceous beneath the European plate margin. Detailed geodynamic reconstructions such as ours provide a robust anchor for future computational models of long-term crustal evolution in the Eastern Hellenides. [ABSTRACT FROM AUTHOR]

The South China region has undergone a complex tectonic history since the Mesozoic era, characterized by significant tectonic regime transformations. However, the mechanism behind these transformations is still subject to debate. This study aims to elucidate the specific manifestations and stress mechanisms driving the tectonic transformations and their geological background. Through field geological surveys, effective stress inversions and analysis of lithofacies palaeogeography in Fujian Province, we have identified six distinct tectonic episodes that occurred during the Mesozoic: (a) late Middle Triassic to early Late Triassic: intense NNE–SSW compression generated an unconformity between the An'ren Formation and Dakeng Formation; (b) middle Late Triassic to early Middle Jurassic: NNE–SSW extension exerted control over the deposition of the Dakeng Formation, Wenbinshan Formation and Zhangping Formation; (c) late Middle Jurassic to early Late Jurassic: NW–SE compression resulted in an unconformity between the Zhangping Formation and Changlin Formation; (d) late Jurassic to early Cretaceous: NW–SE extension influenced the deposition of the Changlin Formation, Nanyuan Formation and Xiaoxi Formation; (e) late Early Cretaceous to Late Cretaceous: a strike–slip stress field caused an unconformity between the Xiaoxi Formation and Shaxian Formation; (f) post‐Late Cretaceous: NE–SW extension occurred. During the late Middle Jurassic to early Late Jurassic period, there was a notable change in the distribution of lithofacies palaeogeography. The coexistence of NE and E‐W‐trending patterns shifted to a predominant NE‐trending pattern, which was controlled by the palaeostress field transitioning from NNE–SSW extension to NW–SE compression. These changes indicate a tectonic regime transformation in Southeast China during this period. Considering the sedimentary, magmatic and tectonic activities, the tectonic evolution of Southeast China was predominantly influenced by the Palaeo‐Tethys tectonic domain from the Early Triassic to early Middle Jurassic and by the Palaeo‐Pacific tectonic domain from the late Middle Jurassic to the Cretaceous. [ABSTRACT FROM AUTHOR]

Subduction initiation in oceans is key to understanding regional and global plate tectonics and ocean basin dynamics; however, its genetic mechanism is still enigmatic. The most famous model that predicts intraoceanic subduction initiation along transform faults or fracture zones (i.e., the Subduction Initiation Rule) has been widely used to explain arc‐like geochemical signatures within the Neo‐Tethyan ophiolites, but fails to account for the speculation and/or calculation of a sub‐parallel relationship between the Jurassic subduction zones and paleo ridges of the western Neo‐Tethys. Here, we propose a ridge‐parallel detachment fault‐hosted subduction re‐initiation model for the Jurassic western Neo‐Tethys. Based on field geological and geochemical evidence, we show that the Refahiye ophiolite in the İzmir–Ankara–Erzincan suture of northern Turkey has diagnostic characteristics indicative of (ultra)slow seafloor spreading. An (ultra)slow‐spreading nature also characterizes many Neo‐Tethyan ophiolites from the Alps to Southeast Asia, either at mid‐ocean ridges or in suprasubduction zones. Due to its extremely weak nature, detachment faults were probably a key candidate for the Jurassic intraoceanic subduction re‐initiation of the western Neo‐Tethys in response to far‐field compression after its long‐lived northward subduction. This model is applicable to both the Jurassic and Early Cretaceous ophiolites, but is questionable for the Late Cretaceous ophiolites. Its utility deponds on the kinematics of ancient plate boundaries and compositions of ophiolites. The detachment fault‐hosted subduction re‐initiation model can explain the arc‐like geochemical features of the Jurassic western Neo‐Tethyan ophiolites, but its effect on the structure and component of ophiolites is diverse. Plain Language Summary: Subduction of oceans is key to understanding regional and global plate tectonics. However, where and how ocean subduction initiates (i.e., subduction initiation) is still enigmatic, in particular for those vanished oceans in Earth's geologic history. In this study, we propose a new model of ridge‐parallel detachment fault‐hosted subduction re‐initiation for the western Neo‐Tethys Ocean in the Jurassic. Based on this study and a global compilation, we show that the ophiolites along the Neo‐Tethyan orogenic belt commonly contain slow‐ and ultraslow‐spreading oceanic lithospheres, either formed at mid‐ocean ridges or in suprasubduction zones. As for the western Neo‐Tethys, detachment faults adjacent to the paleoridges may have served as key candidates for subduction re‐initiation after the long‐lived northward subduction in the early stage, rather than along transform faults or fracture zones as previously suggested. This new model provides alternative explanations for the geochemical and structural diversities of the western Neo‐Tethyan ophiolites, and its utility in global ophiolites needs further examination. Key Points: The Neo‐Tethyan Refahiye ophiolite in northern Turkey formed at an (ultra)slow‐spreading ocean basin, probably at mid‐ocean ridgesDetachment fault is a key candidate for the Jurassic subduction re‐initiation of the western Neo‐Tethys OceanThe utility and diversity of detachment fault‐hosted subduction re‐initiation is discussed for the origin of Neo‐Tethyan ophiolites [ABSTRACT FROM AUTHOR]

This study establishes the structure of the Tisserfine basin, located in the eastern Moroccan High Atlas, through an integrated interpretation of geophysical data. Several types of data were integrated in this work: a gravity map, 243 vertical electrical soundings (VES), a seismic reflection profile; logs of 10 boreholes, geological maps, and field structural measurements. The gravity map shows a succession of lows and highs-oriented WSW-ENE, paralleling the regional structures (synclines and anticlines). Gravity lows are correlated with Triassic evaporites (mostly clays) that were uplifted into high elevation areas (anticlines). Gravity highs correspond to the accumulation of limestones, sandstones, and marls in synclines. A multiscale analysis of gravimetric lineaments shows the main faults bordering the anticlines and synclines. The seismic reflection profile indicates that the Tisserfine syncline is affected by several faults; the Mesozoic formations in the axis of the syncline exceed a depth of 3000 m, and that the anticlines (corresponding to topographic highs) present very high dips (69–87°). The results of 2D resistivity models are in good agreement with geological data and reveal several faults. The models exhibit a conductive layer (marls, 800 m-thick), with intercalations of highly resistive levels inferred to be sandstones. The basement is characterized by very high resistivity values, matching limestones or dolostones. The hydrogeological units consist of two unconfined and three confined aquifers. The piezometric outline shows that the groundwater flows converge towards the Tisserfine wadi with a direction flow to the east. The presence of water throughout the year in several places at the Tisserfine and Zouzfana wadis (e.g. Dfilia (Aghlal) springs) represents the drainage of an unconfined aquifer. [ABSTRACT FROM AUTHOR]

An incomplete albeit well preserved tooth from the Late Jurassic Tacuarembó Formation (Uruguay) shows a character combination only found in abelisaurid theropods, i.e. irregular enamel, hooked distal denticles, interdenticular sulci, lanceolate cross-sectional shape, and straight distal border. Its referral to Abelisauridae was tested via a phylogenetic analysis, with the Uruguayan taxon deeply nested within the clade. This is the first record of abelisaurids in Uruguay and one of the few Jurassic records of the group worldwide. Abelisaurids occur together with ceratosaurids and megalosaurines in the Tacuarembó Formation, revealing a rich Late Jurassic theropod assemblage. [ABSTRACT FROM AUTHOR]

The conditions for the formation of gas hydrates associated with subsea permafrost in the Kara Sea have been predicted based on numerical modeling. The forecast of the distribution of the relic submarine permafrost and related methane hydrate stability zone is given on the basis of solving the equation of thermal conductivity. According to modeling data, an extensive thermobaric relic submarine permafrost zone is predicted within the Kara Sea shelf. The greatest thickness (up to 600 m) of the permafrost is confined to the Taimyr shelf. Based on the results of the analysis of our model, drilling and seismic data, the southwestern shelf of the Kara Sea has insular or sporadic permafrost. In the northeastern part, the nature of the permafrost is also discontinuous, despite the greater thickness of the frozen strata. For the first time, accumulations of cryogenic gas hydrates on the Taimyr shelf have been characterized. The latest drilling data, seismic data reinterpretation, and numerical modeling have shown that the gas hydrate reservoir is confined to unconformably occurring Silurian–Devonian and underlying Triassic–Jurassic strata. The thickness of the gas hydrate reservoir varies from 800 to 1100 m. Based on the interpretation of CDP data and their comparison with model calculations, frozen deposits, and sub-permafrost traps of stratigraphic, anticline and anticline-stratigraphic types were identified for the first time. These pioneering studies allowed us to characterize the thickness and morphology of the gas hydrate reservoir, give a preliminary seismostratigraphic reference, and identify potentially gas hydrate-bearing structures. Due to the favorable thermobaric and permafrost-geothermal conditions, most of the identified traps may turn out to be sub-permafrost accumulations of gas hydrates. In total, at least five potential accumulations of gas hydrates were discovered, confined to structural depressions; the Uedineniya Trough and its side included the Egiazarov Step and North Mikhailovskaya Depression. [ABSTRACT FROM AUTHOR]

A rostrum fragment of a representative of the Toarcian–Early Aalenian (the latest Early Jurassic–the earliest Middle Jurassic) belemnites Arcobelus cf. krimholzi (Sachs, 1970) was found for the first time in kimberlites of the Obnazhennaya pipe of the Kuoika kimberlite field (northeastern Siberian Platform, Olenek Uplift). It was shown that the belemnite records previously known here and dated to the Late Jurassic or Early Cretaceous may be of Bajocian–Bathonian (Middle Jurassic) age. The stage of kimberlite magmatism of 177 ± 1.5 Ma, recently established in the northeastern part of the Siberian craton according to U–Pb geochronological data, falls on the time of the existence of belemnites of the genus Arcobelus. The estimated Late Bajocian–Early Bathonian age of the representative of the genus Pachyteuthis, previously found in kimberlites of the Obnazhennaya pipe, is consistent with the 40Ar/39Ar age (167 Ma), as well as with the age based on some paleomagnetic data (168 ± 11 Ma) reported for the pipe. Taking into consideration the new data on belemnites, the internal part of the shelf should be extended to the territory of the Kuoika kimberlite field in the paleogeographic schemes of the northeastern part of the Siberian Platform during the Toarcian–Early Bathonian. [ABSTRACT FROM AUTHOR]

For Upper Jurassic–Lower Cretaceous rocks of the Bazhenov Formation, a significant positive linear correlation of the content of Th, Hf, Sc, and La with the Al2O3 content was revealed, and their terrigenous genesis was confirmed. It has been determined that the samples, in which the distribution of Sc/Al2O3 and La/Al2O3 values does not satisfy the linear correlation, represent the mixed clayey–siliceous rocks (with P2O5 > 1 wt %) or the substantially pyritized rocks (with the pyrite content exceeding the OM content and C/S ≤ 1), as well as siliceous mudstones (with the SiO2 content > 70 wt %). It is concluded that, in addition to carbonatized rocks, rocks of the above-mentioned types, as well as rocks subjected to the late diagenetic kaolinization, should be excluded before analyzing the geochemical indicators for reconstructing the formation conditions of the Bazhenov Formation. The formation conditions of these rocks were reconstructed based on the analysis of values of several geochemical modules and indicators. Based on the study of CIA and CIW variations, it was confirmed that the Late Jurassic–Early Cretaceous climate in the West Siberian sedimentary basin was warm and semiarid, and it did not change significantly during the entire period under consideration. For rocks of the Bazhenov Formation, several indicators, such as (La/Yb)N and Eu/Eu*, as well as the distribution of trace elements in the Th‒La‒Sc triangular diagram, suggest that rocks of the Bazhenov Formation were deposited in the central and southeastern regions, with the dominant impact of source areas of mafic rocks. [ABSTRACT FROM AUTHOR]

Crown salamanders first appeared in the Middle Jurassic (Bathonian) and remains of these oldest representatives of the group have been found in various vertebrate localities in China, Western Siberia, and Western Europe. Here, we report the discovery of an indeterminate crown salamander in the Middle Jurassic (Bathonian) Peski locality of Moskvoretskaya Formation of the Moscow Region, Russia. This find (a fragmentary trunk vertebra) represents (1) new occurrence of the oldest crown salamanders; and (2) the first fossil record of crown salamanders in the Middle Jurassic of Eastern Europe. The trunk vertebra from the Peski locality resembles those of the modern crown salamanders of the Salamandroidea clade in the presence of spinal nerve foramina and bicapitate transverse processes. If our assignment of the Peski salamander to Salamandroidea is correct, then it is the oldest salamandroid in the fossil record. [ABSTRACT FROM AUTHOR]

One new genus Evacuxyela gen. nov., with two new species, Evacuxyela conflata sp. nov. and Evacuxyela hsiaoae sp. nov., is described and illustrated on the basis of two fossils from the Middle Jurassic Jiulongshan Formation of northeastern China. The new genus Evacuxyela gen. nov. is placed in the subfamily Macroxyelinae Ashmead, 1898, tribe Angaridyellini of Xyelidae, mainly based on veins C and R connected by a bridge next to pterostigma. The two new fossil species are similar, but differentiated by degree of expansion for hind femur, sclerotisation of pterostigma and venational details. In addition, the well-preserved spurs and expanded femora of hind legs provide important morphological characters to enhance our understanding of Xyelidae. ZooBank ID (LSID): Evacuxyela: Evacuxyela conflata: Evacuxyela hsiaoae: [ABSTRACT FROM AUTHOR]

The fossil wood genus Brachyoxylon Hollick et Jeffrey, as an important component of Mesozoic palaeoxylogical assemblages, was widely recorded throughout the world. However, Brachyoxylon fossils were rarely documented in China, and were all reported from the Lower Cretaceous. The Upper Jurassic Tuchengzi Formation is one of the most significant horizons for Jurassic petrified wood in northern China. A new fossil wood species, Brachyoxylon yanqingense sp. nov., was described from the Tuchengzi Formation in Yanqing District of Beijing City, northern China. Anatomically, the new species is characterised by having mixed tracheary radial pitting and araucarioid cross-field pitting. The new finding provides a fresh Jurassic record of Brachyoxylon in China and contributes to further understanding the tempo-spatial distribution of Brachyoxylon in Far-East Asia during the Late Mesozoic. As a fossil wood genus, Brachyoxylon has commonly been related to the extinct conifer family Hirmeriellaceae (Cheirolepidiaceae). Together with an analysis on the floral composition of the Tuchengzi Formation, it is proposed that the Hirmeriellaceae was one of the dominant groups of the forest vegetations in this Late Jurassic flora. [ABSTRACT FROM AUTHOR]

Middle Jurassic terebratulide brachiopods from the Jordan Valley are herein described and a new taxon is added to the previous faunal list. The Callovian rocks (Mughanniyya Formation) of the Tel el Dhahab section have yielded the following terebratulide taxa: Sphriganaria capax, S. costata, S. costellata, S. curtirostra, S. expansa, S. irregularis, S. subcircularis, S. nasuta, S. sp. 1, and S.? sp. 2. A new species Sphriganaria anyamiae sp. nov. is formally described herein. Internal characters of Sphriganaria costata, S. expansa, and S. nosuta have been studied. On the basis of shell microstructure, crural bases, outer and inner hinge plates were differentiated and defined for the first time in the genus Sphriganaria. The secondary layer is homogeneous built of very fine fibres, predominantly anisometric-like in cross-section, 25‒40 μm wide and 8‒15 μm thick. The Callovian Mughanniyya Formation of northwest Jordan is dominated by highly fossiliferous limestones intercalated with marlstone beds with very diverse brachiopod fauna, deposited in shallow, low-energy waters very near the equator. A paleobiogeographic interpretation of the brachiopod faunas in the Ethiopian Province suggests that brachiopods migrated from the north in the Early Jurassic and later became isolated for the remainder of the period. [ABSTRACT FROM AUTHOR]

The Lufeng locality of China was a major biodiversity hotspot for sauropods and tritylodontids during the Early Jurassic. We describe a partly crushed cranium with complete dentition and dentaries from the Early Jurassic Lufeng Formation of China that we refer to Lufengia. The upper postcanine row length is 10.27 mm, representing one of the smallest tritylodontids to date. Lufengia and Dianzhongia are comparable in the upper postcanine dental pattern in having upper postcanine teeth with the cusp formula 2-3-3 and a small distolingual cusp. Based on the new discovery, Dianzhongia is here considered to be an older individual of Lufengia. Through the micro-computed tomography (micro-CT) of the fossil, differing paths of upper and lower dental replacements alongside new details about tooth replacement in tritylodontids have been revealed. [ABSTRACT FROM AUTHOR]

A number of exhumed hydrocarbon traps have been described from the Traill Ø region of East Greenland. This study focuses on the Bjørnedal area where the distribution of bitumen has been mapped out. Bitumen staining clearly has a cross‐cutting relationship to stratigraphic units and can be shown to form distinct palaeo‐accumulations. Detailed petrographic studies show that bitumen occurs as late diagenetic phases in Middle to Late Jurassic sandstones, and is present both as both grain‐coating and pore‐filling phases. Geochemical analyses confirm that the bitumen is organic in composition and is composed largely of carbon and hydrogen. Both H/C ratios and bonds identified by FTIR behave as expected with increasing maturity measured using bitumen reflectance. Together, these results provide strong evidence that the material is pyrobitumen derived from the in situ thermal degradation of a liquid hydrocarbon precursor. On the basis of textures in transmitted and reflected light and quantitative bitumen reflectance distributions, two populations of pyrobitumen may be recognised in some samples. Two phases of Paleogene magmatism occurred in the Traill Ø region. The first late Paleocene – early Eocene phase was related to the opening of the northern North Atlantic in the earliest Eocene, and was experienced throughout East Greenland and the northwest European margin. The later magmatic phase was related to the gradual separation of the Jan Mayen microcontinent from East Greenland through the late Eocene – early Oligocene. A single pyrobitumen phase is recognised in accumulations only affected by the early magmatism, and a second phase is only observed in areas affected by both the early and later magmatism. This relationship is interpreted as evidence for a direct relationship between magmatic phases and bitumen generation. The presence of bitumen formed by the thermal degradation of liquid hydrocarbons during the later magmatic event suggests that a viable petroleum system remained active following the early magmatic event. [ABSTRACT FROM AUTHOR]

Plant nucleotide-binding leucine-rich repeat (NLR) immune receptors generally exhibit hallmarks of rapid evolution, even at the intraspecific level. We used iterative sequence similarity searches coupled with phylogenetic analyses to reconstruct the evolutionary history of HOPZ-ACTIVATED RESISTANCE1 (ZAR1), an atypically conserved NLR that traces its origin to early flowering plant lineages ∼220 to 150 million yrs ago (Jurassic period). We discovered 120 ZAR1 orthologs in 88 species, including the monocot Colocasia esculenta, the magnoliid Cinnamomum micranthum, and most eudicots, notably the Ranunculales species Aquilegia coerulea, which is outside the core eudicots. Ortholog sequence analyses revealed highly conserved features of ZAR1, including regions for pathogen effector recognition and cell death activation. We functionally reconstructed the cell death activity of ZAR1 and its partner receptor-like cytoplasmic kinase (RLCK) from distantly related plant species, experimentally validating the hypothesis that ZAR1 evolved to partner with RLCKs early in its evolution. In addition, ZAR1 acquired novel molecular features. In cassava (Manihot esculenta) and cotton (Gossypium spp.), ZAR1 carries a C-terminal thioredoxin-like domain, and in several taxa, ZAR1 duplicated into 2 paralog families, which underwent distinct evolutionary paths. ZAR1 stands out among angiosperm NLR genes for having experienced relatively limited duplication and expansion throughout its deep evolutionary history. Nonetheless, ZAR1 also gave rise to noncanonical NLRs with integrated domains and degenerated molecular features. The evolutionary history of HOPZ-ACTIVATED RESISTANCE1 (ZAR1) traces its origin to early flowering plant lineages. [ABSTRACT FROM AUTHOR]

This paper presents an interpretation of sedimentologic, paleomagnetic, and geochemical data collected in the Upper Kimmeridgian-Valanginian carbonates of the Giewont series (Giewont and Mały Giewont sections, High-Tatric succession, Western Tatra Mountains, Poland). The studied succession provides insight into the sedimentary conditions prevailing in the South Tatric Ridge (Tatricum), a submarine elevation located between the Zliechov Basin (Fatricum) and the Vahic (=South Penninic) Ocean. The sedimentary sequence includes micrites, pseudonodular limestones, cyanoid packstones, lithoclastic packstone, and encrinites. The results are discussed with regards to their significance for detrital input, paleoclimate, and paleoproductivity, which in turn are considered in the context of both local and regional paleoenvironmental trends and events. The greatest depositional depths during the latest Kimmeridgian-earliest Tithonian are documented by the occurrence of pseudonodular limestones. A Tithonian shallowing trend is demonstrated via the increasing size and roundness of cyanoids, while the final (1)emergence and erosion in the South Tatric Ridge is documented by earliest Cretaceous disconformities. This process might have been related to both falling sea-level during the major eustatic regressive cycle and tectonic uplift caused by the mutually related (re)activation in the Neotethyan Collision Belt and rifting in the Ligurian-Penninic-Vahic Oceans. The highest lithogenic influx (although still low; max 0.5% of Al content) during the Late Kimmeridgian is considered as associated with relatively humid climate conditions, whereas a subsequent decreasing trend is thought to result from aridification during the latest Kimmeridgian-earliest Tithonian. Ultimately, deposition in the High-Tatric zone was affected by both large-scale environmental perturbations characteristic of the latest Jurassic (climate changes, variations in seawater pH, monsoonal upwelling, lithogenic input, etc.), as well as local sedimentary controls, predominantly the oxygenation state of bottom waters and tectonic movements. [ABSTRACT FROM AUTHOR]