Search

Seafloor fabric indicators are the main features used for dating global-scale plate reorganizations. However, the lack of oceanic crusts older than 200 Ma limits their application only to the Mesozoic and Cenozoic eras. Furthermore, in cases such as the mid-Cretaceous time when reversals in Earth's magnetic field did not occur, the plate reorganization ages obtained from seafloor fabric indicators are imprecise. I propose the record of continental deformation as an alternative approach for dating these events. A compilation of cooling/deformation, migmatization, and unconformity ages recorded around the globe collectively indicates that continental deformation associated with the mid-Cretaceous plate reorganization culminated at 107 Ma. This age strongly correlates with ages obtained from other data such as palaeomagnetic poles. Considering that the deformational features similar to which are compiled in this study appear to be temporally correlated with other reorganization events, the record of globally distributed continental deformation might be used for other reorganization events whose timing is poorly constrained. [ABSTRACT FROM AUTHOR]

Plants and insects are two of the more diverse and abundant organisms in terrestrial ecosystems. The fossil record of plant-insect interactions offers crucial insights into the coevolutionary dynamics between these groups, shedding light on the intricate relationships that have shaped terrestrial ecosystems. The study of fossil interactions is especially relevant in mid-Cretaceous ecosystems, a time of dramatic changes in the composition of floras and, consequently, in plantinsect relationships. Here, we describe the first suite of plant-insect interactions from the mid-Cretaceous of Mexico. We studied 554 plant fossils from the El Chango Lagerstatte (Cintalapa Formation, Chiapas, Mexico), including vegetative (leaves) and reproductive structures (fruits and seeds). The flora was dominated by gymnosperms (89.3%) followed by angiosperms (10.7%); other groups, such as pteridophytes and bryophytes, were absent. In total, 5.4% of the plant specimens hosted some damage. Angiosperms (all broad-leafed forms), despite being much less common than gymnosperms, expressed more evidence of damage by herbivores (35.6% of specimens damaged). In contrast, the narrow-leafed gymnosperms, the dominant group in the flora, hosted a much lower proportion of herbivory damage (1.8% of specimens damaged). The diversity of damage types (DTs) was relatively low: 14 DTs were identified, corresponding to seven FFGs, including margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, galling, and mining. Comparison with the other midCretaceous plant-insect assemblages reveals a similar richness of DTs for angiosperms but a lower richness and diversity of DTs on gymnosperms from El Chango. These results indicate preferential herbivory on angiosperms (rather than on the available gymnosperms in the assemblage) by terrestrial arthropods during a period of major changes in the structure of terrestrial ecosystems. However, it is challenging to resolve whether this apparent preference is because insects particularly targeted angiosperms or if the herbivores simply targeted broad leaves in general, since most of the available gymnosperms from El Chango are scale-leafed forms. [ABSTRACT FROM AUTHOR]

The breakup of India from Antarctica in the Early Cretaceous and subsequent seafloor spreading in the NW‐SE direction initiated the formation of the Bay of Bengal and its conjugate Enderby Basin. Two hypotheses are proposed to explain the evolutionary tectonics between India and Antarctica. One involves a single breakup, while the second invokes another breakup episode. Further, a major reorganization of the plate boundaries in the mid‐Cretaceous caused the spreading center to align E‐W by Late Cretaceous. The tectonics involved in this spreading direction change is unknown and difficult to understand as it occurred in the mid‐Cretaceous, coincident with the Cretaceous Normal Superchron. In the present study, we have generated a revised magnetic isochron map of the Bay of Bengal and used the modulus of its analytic signal to understand the evolutionary tectonics between the two plates, India and Antarctica. Mesozoic magnetic anomalies M12n to M0, and mid‐Cretaceous incursion Q2 (108 Ma) are identified in the western basin of the Bay of Bengal, while Q2, Q1 (92 Ma) and Late Cretaceous isochron A34 are inferred in its eastern basin. Gravity grid reconstructions demonstrate asymmetrical crustal accretion in the conjugate corridors. Fan‐shaped spreading and a southward ridge jump between 108 and 92 Ma in the eastern basin, aided the ∼40° clockwise rotation of the spreading center. The presence of volcanic basement beneath the additional crust suggests on‐axis mode of formation for the Ninetyeast Ridge by 100 Ma. The present study favors the two‐phase breakup model for the evolution of these plates. Key Points: Clockwise rotation (∼40°) of the spreading center between India and Antarctica during the mid‐CretaceousFan‐shaped spreading and a southward ridge jump facilitated the clockwise rotation of the spreading centerNinetyeast Ridge formed as on‐axis volcanism during the mid‐Cretaceous [ABSTRACT FROM AUTHOR]

Changes in Earth's magnetic field during the Cretaceous Normal Superchron (CNS) spanning ∼121 Ma to ∼84 Ma hold important clues about the geodynamo evolution. Canonical models predict a persistently strong geomagnetic field with low variability during CNS, which, however, has not been observed in the available absolute paleointensity data and seafloor marine magnetic anomaly (MMA) records. The lack of relative paleointensity (RPI) data across CNS further impedes tests of model predictions. Here, we present a ∼9‐Myr (∼94–∼85 Ma) RPI record from a Turonian to Santonian hemipelagic succession from IODP Site U1512 offshore southern Australia. Detailed paleomagnetic and rock magnetic analyses demonstrate that the ratio of natural remanent magnetization (NRM) demagnetized at 20 mT over magnetic susceptibility (MS), that is, NRM20mT/MS, as a reliable proxy for the RPI of the Upper Cretaceous succession. The new RPI record shows marked changes in both intensity and variability at ∼90.8 Ma. Also, the 6 Myr‐long (∼94–∼88 Ma), near‐continuous, ∼1.2 kyr‐resolution RPI record exhibits a strong positive correlation between field intensity and variability. Assuming this correlation holds for the entire CNS, an extrapolated RPI curve for the entire CNS is obtained by integrating the positive correlation with field variability estimates from the MMA data. The extrapolated RPI curve shows a strong and highly variable field in the middle CNS but a weak and stable field at its beginning and ending. These features imply a much more dynamic geodynamo than previously thought, and provide crucial benchmarks for unraveling the geodynamo evolution during CNS. Plain Language Summary: Cretaceous Normal Superchron (CNS, ∼121 to ∼84 million years ago) marks a nearly 40 million years interval of almost constant normal geomagnetic polarity. Changes in Earth's magnetic field during CNS hold important clues about the evolution of the geodynamo, by which the geomagnetic field was generated. However, whether the geomagnetic field was persistently strong and stable during CNS has been controversial based on estimates from snapshot recordings of igneous rocks and marine magnetic anomaly data. Here, we report a high‐resolution near continuous relative paleointensity (RPI) record of the ∼88–94 million years old interval from a hemipelagic sedimentary succession at IODP Site U1512. The new RPI record documents salient changes in both intensity and variability of the geomagnetic field at ∼90.8 million years ago and a positive correlation between these two parameters toward the ending of CNS. These features imply that the geomagnetic field was strong and highly variable in the middle CNS, but weak and stable at its beginning and ending. These findings indicate much more dynamic geodynamo behavior during the CNS than previously thought, and thus provide important benchmarks for "ground truthing" model simulations to unravel the geodynamo evolution during CNS. Key Points: We report a ∼9 Myr high‐resolution RPI record for the late stage (∼94–∼85 Ma) of CNS from IODP Site U1512 coresThe new RPI record shows a marked change in intensity and variability at ∼90.8 Ma and a positive correlation between these two parametersSalient changes in geomagnetic field's strength and variability imply a much more dynamic geodynamo than previously thought during CNS [ABSTRACT FROM AUTHOR]

In this study, Poinarelektronmiles Fanti & Damgaard, 2020 is considered as a junior synonym of Burmomiles Fanti, Damgaard & Ellenberger, 2018, since no generic diagnostic differences can be found in their type species except for the elytral length, which is a yet unstable and more ecology-related character. The two hitherto known species of Poinarelektronmiles are transferred to Burmomiles or Sanaungulus Fanti, Damgaard & Ellenberger, 2018, including B. ellenbergeri (Fanti & Damgaard, 2020) comb. nov. and S. cuaroni (Bramanti & Fanti, 2022) comb. nov. Meanwhile, B. dominikiweissbachi (Fanti & Müller, 2022) comb. nov., B. kachinensis (Fanti & Müller, 2022) comb. nov. and B. lethi (Fanti & Damgaard, 2020) comb. nov. are transferred from Sanaungulus. Six Sanaungulus species are suggested to be placed in Cantharidae incertae sedis, including S. electrum Fanti & Müller, 2022, S. franziskaeweissbachae Fanti & Müller, 2022, S. nalae Fanti & Müller, 2022, S. morellii Fanti & Damgaard, 2020, S. rosenzweigi Fanti & Damgaard, 2020 and S. ruicheni (Hsiao & Huang, 2018), due to their absence of antennal appendages in males. The gender identity for S. kirstenaeweissbachae Fanti & Müller, 2022 and S. cuaroni originally defined as females are corrected into males, according to their pectinate antennae. Additionally, four new species, S. marginalis sp. nov., S. longicornis sp. nov., S. elongaticollis sp. nov., and S. undecimus sp. nov., are described and illustrated. These results will significantly complement and expand our knowledge on the Burmite cantharid diversity. [ABSTRACT FROM AUTHOR]

Plants and insects are two of the more diverse and abundant organisms in terrestrial ecosystems. The fossil record of plant-insect interactions offers crucial insights into the coevolutionary dynamics between these groups, shedding light on the intricate relationships that have shaped terrestrial ecosystems. The study of fossil interactions is especially relevant in mid-Cretaceous ecosystems, a time of dramatic changes in the composition of floras and, consequently, in plant-insect relationships. Here, we describe the first suite of plant-insect interactions from the mid-Cretaceous of Mexico. We studied 554 plant fossils from the El Chango Lagerstätte (Cintalapa Formation, Chiapas, Mexico), including vegetative (leaves) and reproductive structures (fruits and seeds). The flora was dominated by gymnosperms (89.3%) followed by angiosperms (10.7%); other groups, such as pteridophytes and bryophytes, were absent. In total, 5.4% of the plant specimens hosted some damage. Angiosperms (all broad-leafed forms), despite being much less common than gymnosperms, expressed more evidence of damage by herbivores (35.6% of specimens damaged). In contrast, the narrow-leafed gymnosperms, the dominant group in the flora, hosted a much lower proportion of herbivory damage (1.8% of specimens damaged). The diversity of damage types (DTs) was relatively low: 14 DTs were identified, corresponding to seven FFGs, including margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, galling, and mining. Comparison with the other mid-Cretaceous plant-insect assemblages reveals a similar richness of DTs for angiosperms but a lower richness and diversity of DTs on gymnosperms from El Chango. These results indicate preferential herbivory on angiosperms (rather than on the available gymnosperms in the assemblage) by terrestrial arthropods during a period of major changes in the structure of terrestrial ecosystems. However, it is challenging to resolve whether this apparent preference is because insects particularly targeted angiosperms or if the herbivores simply targeted broad leaves in general, since most of the available gymnosperms from El Chango are scale-leafed forms.

Abstract In the Gasht-Masuleh area in the Alborz Mountains, gabbroic magma intruded Palaeozoic metasediments and Mesozoic sediments and crystallised as isotropic and cumulate gabbros. LREE enrichment points to relatively low degrees of mantle melting and depletion of Ti, Nb and Ta relative to primitive mantle points to an arc related component in the magma. Clinopyroxene compositions indicate MORB to arc signatures. U–Pb zircon crystallisation ages of 99.5 ± 0.6 Ma and 99.4 ± 0.6 Ma and phlogopite 40Ar/39Ar ages of 97.1 ± 0.4 Ma, 97.5 ± 0.4 Ma, 97.1 ± 0.1 Ma, within 2σ error, indicate that gabbro intrusion occurred in the (Albian-)Cenomanian (mid-Cretaceous). As active subduction did not take place in the Cretaceous in North Iran, the small volume mafic magmatism in the Gasht-Masuleh area must be due to local, extension-related mantle melting. Melting was most likely caused by far field effects triggered by roll-back of the Neo-Tethys subducting slab. As subduction took place at a distance of ~ 400 km (present distance) from the Alborz Mountains, the observed arc geochemical signatures must be inherited from a previous subduction event and concomitant mantle metasomatism, possibly in combination with contamination of the magma by crustal material.

The Mid‐Cretaceous was characterized by long‐term and stabilized high temperatures confirmed by numerous palaeoclimatic information from marine sedimentary archives. However, few terrestrial records have yet been employed to verify the terrestrial humidity under this long‐term hot climate. The Liupanshan Basin, located in central China during the Cretaceous contains thick Aptian‐Albian sediments. Here, we reconstructed a long‐term palaeovegetational record during late Aptian to Albian from the Huoshizhai Section and Sikouzi Section, Liupanshan Basin. Five palynological assemblages were defined from the bottom to top of these strata, and a total of 124 types of palynomorphs including 47 spore species and 77 gymnosperm pollen species were recognized in the palynological assemblages. Sporopollen analysis revealed that the spore‐pollen spectra of Huoshizhai Section were dominated by Perinopollenites and Bisaccate pollen. In Sikouzi section, the Classopollis content dominate in all samples (average 63.8%), with a few other pollen, including conifer bisaccates types, Perinopollenites, Jiaohepollis, Ephedripites, Cycadopites and a few spores. The sporopollen assemblage reflected that the flora of the central Asia continent gradually changed from Taxodiacean‐dominated to Cheirolepidiaceae‐dominated in the late Aptian and the Albian, which further indicates that the central Asia continent palaeoclimate gradually changed from a wet and cold climate to a long‐term dry and hot climate with small fluctuation. In addition, the Classopollis content also presented a slightly increased trend from late Aptian to late Albian, which probably indicated a gradually intensified hot and dry climate. The thermophilic floral changes and warmer/cooler ratio of the Sporomorph Ecogroup Model at the middle Madonghshan Formation also shows slightly decreased trends which correspond to the global short‐term cooling events at the Aptian‐Albian transition. [ABSTRACT FROM AUTHOR]

In the Gasht-Masuleh area in the Alborz Mountains, gabbroic magma intruded Palaeozoic metasediments and Mesozoic sediments and crystallised as isotropic and cumulate gabbros. LREE enrichment points to relatively low degrees of mantle melting and depletion of Ti, Nb and Ta relative to primitive mantle points to an arc related component in the magma. Clinopyroxene compositions indicate MORB to arc signatures. U–Pb zircon crystallisation ages of 99.5 ± 0.6 Ma and 99.4 ± 0.6 Ma and phlogopite 40Ar/39Ar ages of 97.1 ± 0.4 Ma, 97.5 ± 0.4 Ma, 97.1 ± 0.1 Ma, within 2σ error, indicate that gabbro intrusion occurred in the (Albian-)Cenomanian (mid-Cretaceous). As active subduction did not take place in the Cretaceous in North Iran, the small volume mafic magmatism in the Gasht-Masuleh area must be due to local, extension-related mantle melting. Melting was most likely caused by far field effects triggered by roll-back of the Neo-Tethys subducting slab. As subduction took place at a distance of ~ 400 km (present distance) from the Alborz Mountains, the observed arc geochemical signatures must be inherited from a previous subduction event and concomitant mantle metasomatism, possibly in combination with contamination of the magma by crustal material. Highlights: Gasht-Masuleh gabbros calc-alkaline, extensional setting, inherited arc signature (Albian-) Cenomanian, 99 Ma zircon ages 97–98 Ma 40Ar/39Ar phlogopite ages Mantle upwelling and formation of gabbros triggered by Neo-Tethys slab roll-back causing extension [ABSTRACT FROM AUTHOR]

Teleosts form the largest clade among the extant actinopterygians, some extinct forms of which are still poorly positioned in the phylogeny. The Tselfatiiformes and Araripichthyidae are such examples. A newly discovered genus and species from the Cenomanian of Haqel, Lebanon, is described, and its systematic affinities are discussed. It shares several characteristics (deep and compressed body with elongated and high dorsal and anal fins, edentulous maxilla, and sinusoidal vertebral column) with both the Tselfatiiformes and Araripichthys, making it difficult to place within the teleosts. It shares with Abisaadichthys, among the tselfatiiforms' family Protobramidae, an autogenous retroarticular, and with Araripichthys premaxillae with a long ascending process, well-developed maxillary articular condyle and two supramaxillae. Moreover, it shows some unique characteristics (a thin maxilla with two large supramaxillae, fused articular and angular bones, mandibular sensory canal opening on the external side of the anguloarticular, first dorsal pterygiophore having the same enlarged semi-circular plate as the first anal pterygiophore) justifying its generic status. Comments on some of the protobramids are presented, and the necessity for phylogenetic analysis to place the Tselfatiiformes, Araripichthys and Ypsiloichthys within the teleosts is outlined. [ABSTRACT FROM AUTHOR]

The Mesozoic Teleostei †Ichthyodectiformes presents a widespread distribution in marine brackish and freshwater deposits worldwide. The Brazilian fossil record of this group is represented by five nominal genera distributed exclusively in the sedimentary basins of Northeast Brazil (cf. Parnaíba, Sergipe-Alagoas, Recôncavo, Tucano, and Araripe). In the Araripe basin, the unique representative of the order is †Cladocyclus gardneri, restricted to the Crato and Romualdo Formations. Recent collecting efforts carried out in the Araripe Basin led to the discovery of two specimens of †Cladocyclidae. Based on the comparison with the known Brazilian taxa, we conclude that this new record represents a new genus and species of this clade. †Cladocynodon araripensis represents the first vertebrate described from the dark shales of the "Batateira Beds" of the Barbalha Formation and differs from the other †Cladocyclidae by the presence of hypertrophied bony fangs at the anterior region of the dentary, with other relatively small true teeth abruptly reduced posteriorly, and by presenting premaxillary and maxillary teeth significantly reduced in size. †Cladocynodon araripensis increases the anatomic diversity and temporal range of †Cladocyclidae in Gondwana. [ABSTRACT FROM AUTHOR]

A granite pluton, named Omi Granite, is exposed along the Japan Sea coast at the northern end of the Hida Mountains. This pluton was emplaced in the Permian strata, a member of the Hida Marginal Belt which is thought to be a tectonic boundary zone between the Hida Belt of a Paleozoic-Mesozoic continental block and the Mino Belt of Jurassic accretionary complex. The Omi pluton consists of medium-grained biotite granite, showing relatively low magnetic susceptibility lower than ~2.5X10-3 SI. Whole rock chemical analysis yielded 74.42 wt.% SiO2, and 4.47 wt.% K2O, slightly higher than the average K2O content of Japanese granitoids. K-Ar age dating for a purified biotite fraction yielded 92.5±2.3 Ma, which is consistent with published fission-track and U-Pb ages for zircons. These results suggest that the Omi Granite is a member of small granite plutons emplaced in the Hida Belt in the mid Cretaceous of 100±10 Ma. [ABSTRACT FROM AUTHOR]

Sedimentological and stratigraphical studies in the Cretaceous series of the Tendrara dome led to the discovery of fossiliferous levels in the pre-Cenomanian and Cenomanian deposits, providing significant biostratigraphic, paleoenvironmental, and paleogeographic results. In the SW part of the Tendrara dome, the predominantly terrigenous deposits at the base of the pre-Cenomanian (Dekkar 1 Formation) yielded dinosaur eggshell fragments and charophytes, in particular Clavatoraceans, pointing to the Barremian-Aptian. Above this unit, two beds with fish remains were discovered in the Dekkar 2 Formation and at the base of the Dekkar 3 Formation, respectively. To the NE of the Tendrara dome, a fossiliferous site with diversified benthic fauna and abundant fish remains was discovered in a thin marly unit unconformably overlying the Middle Jurassic basement. Elasmobranch micro-remains indicate a Cenomanian age for this unit. The SW-NE correlations indicate a marked thickness reduction and lateral facies variations, implying a strong asymmetry in the Cretaceous paleogeography of the dome. The first continental and lagoonal basins of the Barremian-Aptian and Albian?-Cenomanian are located in the southern part of the Tendrara dome. The Cenomanian transgression, initiated from the south, gradually covered the dome, depositing reduced coastal plain elasmobranch-rich facies in its northern part. The Tendrara dome constituted a paleogeographic barrier, limiting the first transgressions of the Cenomanian sea. This paleostructure is part of an emerged area (Idrissides High) located between the Tethyan Ocean and the Saharan epicontinental sea. • Clavatoracean charophytes allow to date the Barremian-Aptian. • Elasmobranch associations indicate a Cenomanian age. • Lagoonal-marine precursor episodes of the Cenomanian-Turonian transgression. • Strongly differentiated pre-Cenomanian and Cenomanian paleogeography. • The Tendrara dome constituted a Cenomanian paleogeographic coastal edge. [ABSTRACT FROM AUTHOR]

Teleosts form the largest clade among the extant actinopterygians, some extinct forms of which are still poorly positioned in the phylogeny. The Tselfatiiformes and Araripichthyidae are such examples. A newly discovered genus and species from the Cenomanian of Haqel, Lebanon, is described, and its systematic affinities are discussed. It shares several characteristics (deep and compressed body with elongated and high dorsal and anal fins, edentulous maxilla, and sinusoidal vertebral column) with both the Tselfatiiformes and Araripichthys, making it difficult to place within the teleosts. It shares with Abisaadichthys, among the tselfatiiforms’ family Protobramidae, an autogenous retroarticular, and with Araripichthys premaxillae with a long ascending process, well-developed maxillary articular condyle and two supramaxillae. Moreover, it shows some unique characteristics (a thin maxilla with two large supramaxillae, fused articular and angular bones, mandibular sensory canal opening on the external side of the anguloarticular, first dorsal pterygiophore having the same enlarged semi-circular plate as the first anal pterygiophore) justifying its generic status. Comments on some of the protobramids are presented, and the necessity for phylogenetic analysis to place the Tselfatiiformes, Araripichthys and Ypsiloichthys within the teleosts is outlined.

Simple Summary: Two new genera and two new species of Oecanthinae (Gryllidae) are described that are from northern Myanmar amber. They are the oldest representatives of tree crickets, supporting the previous estimation of the origin of Oecanthinae by molecular data. These new findings improve our knowledge of the evolution of the Gryllidae. The abundance of insects in Burmese amber illustrates a highly diverse insect community of the mid-Cretaceous, but the records of crickets are relatively rare. Here, we erect two new genera with two new species, Birmanioecanthus haplostichus gen. et sp. nov. and Apiculatus cretaceus gen. et sp. nov., based on two new specimens from northern Myanmar amber. These new species can be assigned to the subfamily Oecanthinae (Orthoptera: Gryllidae) by their prognathous head, slender body and metatibiae, and protibiae with large tympana. These new findings are the first and earliest fossil record of tree crickets and shed light on the evolution of Oecanithinae. [ABSTRACT FROM AUTHOR]

We described ten nymph specimens of an insect, Mesophthirus engeli (incertae sedis), from the mid-Cretaceous Myanmar (Burmese) amber, preserved together with partially damaged dinosaur feathers. Based on the ectoparasitic morphological characters of these tiny insect nymphs, we concluded that Mesophthirus engeli was the earliest known feather-feeding insect and that integument-feeding behaviors of insects appeared during or before the mid-Cretaceous along with the radiations of feathered dinosaurs including birds. Grimaldi and Vea raised some concerns about these feather-feeding insects and supposed that the nymphs of Mesophthirus engeli were crawlers of scale insects, i.e. nymphal stages of Coccoidea, coincidentally co-occurring with damaged feathers. Shcherbakov (2022, this issue) accepted and developed the argumentation of Grimaldi and Vea (2021). We would like to address their concerns here. [ABSTRACT FROM AUTHOR]

Extreme climatic conditions, volcanism, and paleogeographical distribution presumably led to the Oceanic Anoxic Event 2 (OAE 2), one of the most disruptive events for Cretaceous ecosystems. Although the terrestrial response to this issue is barely studied, a turnover within the plant communities seems to be linked to the OAE 2, besides the well-known extinction of several marine groups. In this study, palynological and δ13C org analyses were combined to research the sediments from DSDP Site 398 (Vigo Seamount) cores 398D-58 to 398D-56 (upper Albian to lower Turonian). The δ13C org curve exhibits a Carbon Isotopic Excursion (CIE) observed between the interval 948,60 and 947,77 m below seafloor (mbsf), corresponding to the OAE 2. Four palynological assemblages were differentiated, ranging from the uppermost Albian to the lower Turonian. These assemblages comprised diverse marine and terrestrial communities with generally excellent preservation. In addition to previous biostratigraphic works, we present a more detailed chronostratigraphy of DSDP Hole 398D based on palynomorphs. The paleoecological reconstruction reveals the significant changes during the OAE 2 period: a decrease in the diversity and abundance of dinoflagellate cysts and a shift to angiosperm-dominated terrestrial communities (i.e., Normapolles) which, unlike other sites, occurs prior to the maximum values of δ13C. [Display omitted] • δ13C org isotope data confirm the presence of the OAE 2 at DSDP Site 398D. • Detailed palynostratigraphy for the upper Albian—lower Turonian interval. • Four different palynological assemblages were identified. • Marked decrease in marine community abundance and diversity during the OAE 2. • Normapolles high diversification and dominance related to the OAE 2. [ABSTRACT FROM AUTHOR]

The Ripipterygidae is a small orthopteran family which comprises several bizarre species. A new genus and species of Ripipterygidae, Kallosripipteryx zhangi sp. nov., is described based on a well-preserved inclusion from mid-Cretaceous Kachin amber. The new genus and species are established based on the following combination of characters: wider interocular distance, prosternal process present, fusiform mesotibia, metatibia apical spurs about 1/3rd of metatarsus in length; paraproctal lobe two-segmented; and paraproctal lobe distinctly longer than ovipositor. Additionally, we recognize a kind of metatarsal structure among most Mesozoic ripipterygids: the outer side of apical process is triangular in lateral view. Our new find enriches the biodiversity of fossil Ripipterygidae as well as Tridactyloidea, and provides a new interpretation of biogeography of Tridactyloidea. [ABSTRACT FROM AUTHOR]

Here we describe four new fossil species of soldier beetles, Burmomiles brevicollis sp. nov., B. angustipennis sp. nov., B. recticollis sp. nov., B. dentatus sp. nov., which are collected from the mid-Cretaceous amber in Kachin (Hukawng valley) of Northern Myanmar. They are placed in Burmomiles Fanti, Damgaard et Ellenberger, 2018 based on the male antennomeres IV‒X each with an antennal appendage inserted at a basal cavity on the ventral side, and tibiae hardly longer than femora, tarsomeres I normal and less than twice as long as II. Moreover, with more species added, the key for the identification of all Burmomiles species is updated. These results will significantly expand our knowledge on the species diversity of Burmite cantharids. [ABSTRACT FROM AUTHOR]

The Albian-Santonian interval (∼113–83 Ma) is a key interval for Cretaceous climatic and environmental changes. This interval is associated to a rise in sea level until the Late Cenomanian (∼ 94 Ma) and to a progressive increase in oceanic temperatures, leading to consider the Late Cenomanian-Santonian interval (∼ 94–83 Ma) as the warmest period of the last 200 Myr. While the Albian-Santonian interval has been well studied in the Northern Hemisphere, the climatic and environmental variations and their consequences on weathering conditions are less documented of the Southern Hemisphere, especially in mid and high latitudes. To better understanding the evolution of weathering conditions, associated to continental climate and sea level changes during this key period, an integrated study, based on a coupled mineralogical and geochemical approach, was carried out on the clay-sized (< 2 μm) fraction from sediments of International Ocean Discovery Program Site U1513 (Mentelle Basin, South-western Australia) and Oceanic Drilling Program Site 763 (Carnarvon Basin, North-western Australia). To determinate variations in weathering conditions, the mineral assemblages of the clay fraction was determined by X-ray diffraction and observed for selected samples by electron microscopy. To identify sources of clay minerals, the concentrations of major and selected trace elements, including rare earth elements, together with strontium and neodymium isotopic measurements were performed on the clay-sized fraction. The X-ray diffraction analyses reveal that clay fraction is dominated by R0-type illite/smectite mixed-layers (smectites), followed by variable proportions of illites, kaolinites for both sites and only on Site 763 of palygorskites. These clay minerals are associated with opal and clinoptilolites. Electron microscopy observations have highlighted the dominance of detrital fleecy smectites but also the occurrence of recrystallized lathed smectites and volcanogenic folded smectites for Site U1513, and authigenesis of clay minerals, associated to palygorskites especially on Turonian to Santonian deposits for Site 763. This authigenesis, confirmed by negative cerium anomaly, is also carried by other minerals in the clay-sized fraction (e.g., clinoptilolites, barite). These different authigenic minerals record a seawater-derived isotopic signature. Therefore, isotopic compositions of the clay-sized fraction reflect a mix between a continental contribution, carried by detrital clay minerals and marine one, supported by authigenic minerals, which complicates the identification of sediment sources. However, despite this, our study demonstrates the major influence of sea level variations on mineralogical variations from Albian to Cenomanian in Western margin of Australia. The decrease in kaolinite proportions at Site U1513 from the Albian to the end of the Cenomanian, is probably related to the increase of sea level, which cause a decrease in detrital inputs in the Mentelle Basin associated with a decrease of weathering and drainage conditions. The progressive sea level rise has also enhanced the effect of the differential settling process of clay minerals by the deposition of coarse clays (e.g., kaolinites and illites) on the continental shelf. Kaolinite-bearing clay deposits, derived from the weathering of the Western Australian Craton during the Albian-Cenomanian times, have been progressively substituted from the Turonian by a carbonate sedimentation, for which the terrigenous component consists only of rare detrital and volcanogenic smectites. In Site 763, the occurrence in kaolinite content during the Coniacian would indicate a decrease of differential settling process related to the weathering of the north part of the Western Australia Craton. [ABSTRACT FROM AUTHOR]

• Mid-Cretaceous paleosols of the Puesto El Moro Formation, southern Patagonia (∼54° paleo-S) • Reconstruction of a deep-time Critical Zone. • Paleosols classified as hydromorphic Histosols, Alfisols, and Vertisols. • Paleoclimate during Cenomanian greenhouse was temperate and humid with seasonality. The mid-Cretaceous was a period characterized by a global greenhouse climate. Paleosols can be used to reconstruct Critical Zones of the Earth́s past and enhance our comprehension of such greenhouse conditions. Through macro- and micromorphological, clay-mineralogy, and bulk geochemical analyses of the paleosols, we conducted a deep-time Critical Zone reconstruction at mid-high paleolatitudes of the mid-Cretaceous Puesto El Moro Formation in the southern Patagonia (Austral-Magallanes Basin). Paleosols were classified as hydromorphic Histosol-like paleosols (Kachaike pedotype), Alfisols like-paleosols (La Lila pedotype), and Vertisol like-paleosols (La Bernarda pedotype). The analysis of these paleosols facilitated the reconstruction of the deep-time Critical Zone and enables us to infer the four scientific spheres (lithosphere, hydrosphere, biosphere, and atmosphere). Different types of paleosols developed under different parent materials with specific soil-moisture regime and drainage class. Overall, paleosols took place during temperate and humid conditions with a marked seasonality of the precipitations. The paleoclimate reconstruction obtained here provides new data from mid-high paleolatitudes and agrees with the current mid-Cretaceous climate reconstructions in the context of a greenhouse world. [ABSTRACT FROM AUTHOR]

The Mesozoic Teleostei †Ichthyodectiformes presents a widespread distribution in marine brackish and freshwater deposits worldwide. The Brazilian fossil record of this group is represented by five nominal genera distributed exclusively in the sedimentary basins of Northeast Brazil (cf. Parnaíba, Sergipe-Alagoas, Recôncavo, Tucano, and Araripe). In the Araripe basin, the unique representative of the order is †Cladocyclus gardneri, restricted to the Crato and Romualdo Formations. Recent collecting efforts carried out in the Araripe Basin led to the discovery of two specimens of †Cladocyclidae. Based on the comparison with the known Brazilian taxa, we conclude that this new record represents a new genus and species of this clade. †Cladocynodon araripensis represents the first vertebrate described from the dark shales of the “Batateira Beds” of the Barbalha Formation and differs from the other †Cladocyclidae by the presence of hypertrophied bony fangs at the anterior region of the dentary, with other relatively small true teeth abruptly reduced posteriorly, and by presenting premaxillary and maxillary teeth significantly reduced in size. †Cladocynodon araripensis increases the anatomic diversity and temporal range of †Cladocyclidae in Gondwana.

During the Early Cretaceous, Australia was flooded by the epicontinental Eromanga Sea, deposits of which occur across the Great Australian Superbasin. However, the mid‐Cretaceous retreat of this shallow sea, and the resultant palaeogeographic and sediment distribution patterns, are poorly understood. This study chronicles the Eromanga Sea's northward regression through the Carpentaria Basin as captured in the sedimentary record of the Normanton Formation. We achieve this by integrating sedimentary facies analysis of cores from across the Carpentaria Basin with palynology, sandstone petrography and U‐Pb detrital zircon geochronology. Results indicate that the Normanton Formation was deposited between ca. 100 and 96 Ma, and that it represents a large, northward‐prograding, likely river‐dominated delta system. The unit's volcanoclastic nature is exhibited through abundant lithic volcanics and devitrified glass, with a prominent, near‐depositional detrital zircon population attributed to a proximal continental magmatic arc‐derived source hypothesised to parallel the eastern seaboard of Australia at this time. The Normanton Formation is temporally correlative with the lower‐middle portions of the similarly volcanoclastic Winton Formation in the Eromanga Basin, which drained southwards into the Cenomanian‐Santonian Ceduna River Delta system. However, Normanton Formation strata display subtly different provenance signatures and drainage patterns, indicating input from similar, but likely more northern source terrains than much of the contemporaneous Winton Formation. These sediments were unlikely recycled southwards into the Ceduna Delta like those of the Winton Formation; rather they drained northward following the retreat of the Eromanga Sea through the Carpentaria Basin, indicating a Cretaceous drainage divide between two river systems, with distinct northern and southern drainage catchments. The mid‐Cretaceous palaeogeography of eastern Australia is analogous to that of the Late Cretaceous Western Interior Seaway of North America, in which the retreat of a shallow epicontinental sea is marked by the rapid deposition and progradation of multiple large, geographically distinct clastic wedges. [ABSTRACT FROM AUTHOR]

In order to facilitate the search for new play concepts and exploration opportunities, a sequence stratigraphic synthesis of the Cenomanian–Turonian interval of the Arabian Plate has been compiled. The synthesis is based on published datasets which have been analysed within a temporal framework constrained by biostratigraphy and isotope stratigraphy. The high stratigraphic resolution allows the palaeogeography of the study area to be mapped within 3rd order depositional sequences, and the relative influence of eustacy and tectonics on basin development to be evaluated. This significantly improves the prediction of stratigraphic architecture and depositional morphology at the scale of the entire tectonic plate. Conceptual models informed by outcrop and subsurface observations have been applied to characterize the development of intrashelf basins in depositional settings that are either isolated from siliciclastics (symmetric intrashelf basin model) or influenced by siliciclastics (asymmetric intrashelf basin model). The application of a sequence stratigraphic model across regional well log transects facilitates an understanding of stratigraphic architecture and acts as an important control for the generation of a new suite of gross depositional environment (GDE) maps. These maps characterize the palaeogeography at a previously unprecedented resolution and scale during both periods of high relative sea level (maximum flooding surface and highstand systems tract) and low relative sea level (lowstand systems tract). The maps are complemented by sequence isopachs which reveal changes in accommodation through time and space. This approach helps characterize the preserved distribution and stratigraphic configuration of petroleum systems elements. In the Shilaif (UAE), Natih (Oman) and Sarvak (Iran) intrashelf basins, condensed, organic‐rich carbonate source rocks were deposited in restricted, anoxic conditions. These basins resulted from differential aggradation of the carbonate platform during the transgressive systems tract. Grainy, rudist‐debris –rich carbonate reservoir rocks developed along the margins of the intrashelf basins during highstand progradation. Claystones in the overlying sequence may form intraformational seals and were deposited during retrogradation of the shoreline associated with sea‐level rise. By contrast in the Najaf intrashelf basin (Iraq), there is a significant siliciclastic component sourced from the Arabian Shield. This influx resulted in a mixed carbonate‐siliciclastic ramp depositional system on the proximal, western margin of the basin, and an apparent absence of organic‐rich intervals within the central basin succession. Grainy carbonate reservoir rocks are restricted to the eastern margin and are charged by older source rocks within the underlying stratigraphy. The GDE maps record the configuration of these petroleum systems elements within the Cenomanian–Turonian interval and form the basis for play screening. The Cenomanian–Turonian interval is punctuated by the major mid‐Turonian unconformity which is a tectonostratigraphic boundary of considerable geological and economic significance. In the southern and eastern part of the Arabian Plate, this unconformity has a differential erosion profile that facilitates a subcrop play with exploration potential. Identifying subtle stratigraphic traps is challenging, but by combining GDE facies with the mapped preservation limit for each sequence, it is possible to identify areas where rudist‐rich reservoir facies with potential karst enhancement are overlain by a regional claystone seal, high‐grading areas with subcrop trap potential. [ABSTRACT FROM AUTHOR]

While the terrestrial fossil record of the mid-Cretaceous interval (Aptian to Cenomanian) in North America has been poorly studied, the recent focus on fossil localities from the western United States has offered a more detailed picture of vertebrate diversity, ecosystem dynamics and faunal turnover that took place on the western landmass of Laramidia. This is in stark contrast to the terrestrial record from the eastern landmass of Appalachia, where vertebrate fossils are rare and consist mostly of isolated and fragmentary remains. However, a detailed understanding of these fossil communities during this interval is necessary for comparison of the faunal patterns that developed during the opening of the Western Interior Seaway (WIS). The Woodbine Group of Texas is a Cenomanian age (95-100 mya) deposit consisting of shallow marine, deltaic, and terrestrial communities, which were only recently separated from their western counterparts. These deposits have yielded a wealth of vertebrate remains, yet non-avian theropods are still largely unknown. Recently, multiple localities in the Lewisville Formation of the Woodbine Group have yielded new non-avian theropod material, including numerous isolated teeth and postcranial remains. While largely fragmentary, this material is sufficiently diagnostic to identify the following taxa: a large-bodied carcharodontosaur, a mid-sized tyrannosauroid, a large ornithomimosaur, a large dromaeosaurine, a small dromaeosaurid, a small troodontid, and a small coelurosaur. Some of these groups represent the first occurrence for Appalachia and provide a broader understanding of a newly expanded faunal diversity for the Eastern landmass. The Lewisville Formation theropod fauna is similar in taxonomic composition to contemporaneous deposits in Laramidia, confirming that these groups were widespread across the continent prior to extension of the WIS. The Lewisville Formation documents the transitional nature of Cenomanian coastal ecosystems in Texas while providing additional details on the evolution of Appalachian communities shortly after WIS extension. [ABSTRACT FROM AUTHOR]

While the terrestrial fossil record of the mid-Cretaceous interval (Aptian to Cenomanian) in North America has been poorly studied, the recent focus on fossil localities from the western United States has offered a more detailed picture of vertebrate diversity, ecosystem dynamics and faunal turnover that took place on the western landmass of Laramidia. This is in stark contrast to the terrestrial record from the eastern landmass of Appalachia, where vertebrate fossils are rare and consist mostly of isolated and fragmentary remains. However, a detailed understanding of these fossil communities during this interval is necessary for comparison of the faunal patterns that developed during the opening of the Western Interior Seaway (WIS). The Woodbine Group of Texas is a Cenomanian age (95–100 mya) deposit consisting of shallow marine, deltaic, and terrestrial communities, which were only recently separated from their western counterparts. These deposits have yielded a wealth of vertebrate remains, yet non-avian theropods are still largely unknown. Recently, multiple localities in the Lewisville Formation of the Woodbine Group have yielded new non-avian theropod material, including numerous isolated teeth and postcranial remains. While largely fragmentary, this material is sufficiently diagnostic to identify the following taxa: a large-bodied carcharodontosaur, a mid-sized tyrannosauroid, a large ornithomimosaur, a large dromaeosaurine, a small dromaeosaurid, a small troodontid, and a small coelurosaur. Some of these groups represent the first occurrence for Appalachia and provide a broader understanding of a newly expanded faunal diversity for the Eastern landmass. The Lewisville Formation theropod fauna is similar in taxonomic composition to contemporaneous deposits in Laramidia, confirming that these groups were widespread across the continent prior to extension of the WIS. The Lewisville Formation documents the transitional nature of Cenomanian coastal ecosystems in Texas while providing additional details on the evolution of Appalachian communities shortly after WIS extension.

Understanding the tectonic framework of the Antarctic Peninsula is hindered by a paucity of paleomagnetic data from key locations. In this study, we present paleomagnetic data from the South Shetland Islands, to the northwest of the Antarctic Peninsula, which provides valuable paleoposition constraints on the Western domain of the Antarctic Peninsula. We report a key reliable paleopole (58.1°S, 354.3°E, A95 = 6.3°) from Livingston Island in the South Shetland Islands at ∼102 Ma. Plate reconstruction models from the Early Cretaceous attach the South Shetland Islands to the Pacific margin of southern Patagonia‐Fuegian Andes at ∼140 Ma. The South Shetland Islands then experienced southward translation to its current position to the northwest of the Antarctic Peninsula following counterclockwise rotation during ∼100–90 Ma. A similar counterclockwise rotation has also been identified from southern Patagonia‐Fuegian Andes but is absent in the Antarctic Peninsula, suggesting a direct affinity between the South Shetland Islands and southern Patagonia‐Fuegian Andes. However, the consistent, almost northward Cretaceous paleomagnetic declination in the Antarctic Peninsula, and the near‐synchronous tectonic‐magmatic history between the Antarctic Peninsula and the southern Patagonia‐Fuegian Andes support an autochthonous continental subduction model for most of the Antarctic Peninsula. Plain Language Summary: In this study, we applied paleomagnetic constraints on the autochthonous continental subduction model and allochthonous terrane accretion model in the explanation of the tectonic framework of the Antarctic Peninsula. Our new data reveal a consistent counterclockwise rotation occurred both at the South Shetland Islands and southern Patagonia‐Fuegian Andes during ∼100–90 Ma, suggesting the affinity of these places. This is supported by the previous reported ∼140 Ma plate reconstruction, which attached the South Shetland Islands to the Pacific margin of southern Patagonia‐Fuegian Andes. However, the lack of significant tectonic rotation suggests that most parts of the Antarctic Peninsula were formed during the Pacific plate subduction and support an autochthonous continental subduction model. Key Points: We have obtained a key mid‐Cretaceous paleopole (58.1°S, 354.3°E, A95 = 6.3°) from the Byers Peninsula, South Shetland IslandsSouth Shetland Islands located at the Pacific margin of southern Patagonia‐Fuegian Andes during the Early to mid‐CretaceousConsistent almost northward paleomagnetic declination support an autochthonous model for most part of the Antarctic Peninsula [ABSTRACT FROM AUTHOR]

Christophus myanmarensis gen. et sp. nov., Christophus ohmkuhnlei gen. et sp. nov., and Mintara parva gen. et sp. nov., three new species and two new genera of belytine wasps (Diapriidae: Belytinae) are described and figured from males preserved in mid-Cretaceous Kachin (Burmese) amber. These new fossils enrich the fossil record of Cretaceous diapriids, summarized here, demonstrating the diversity of the family before the K/Pg extinction and suggesting an older origin for the family. [ABSTRACT FROM AUTHOR]

Abstract We record a new ichnosite bearing dinosaur tracks from the mid-Cretaceous (Aptian? -Cenomanian) of Brazil. The Fazenda dos Pingos ichnosite is situated within a sandstone pavement of the Açu Formation (Açu 3 unit) from the Potiguar Basin in the State of Rio Grande do Norte. This is a small ichnofauna, with only a few individual isolated tracks. One specimen is unequivocally attributed to a large sauropod and another to an ornithopod. Two other specimens represent poorly preserved tracks assigned to sauropods. This is the first record of dinosaur tracks from the Potiguar Basin and from the Rio Grande do Norte State.

Many insects have been described from the mid-Cretaceous Myanmar (Burmese) amber in recent years, including about 50 families of wasps. However, only two species of sawfly, Syspastoxyela rhaphidia and Striaexyela longicornis (Syspastoxyelidae), have been described in Myanmar amber, in contrast to more than 100 species of sawflies from the Mesozoic of Kazakhstan and China. Herein, we describe three new taxa of sawflies, Deltoxyela engeli gen. et sp. nov., Syspastoxyela pinguis sp. nov. and Syspastoxyela simpla sp. nov., based on six amber pieces with 21 specimens of sawflies from the mid-Cretaceous Myanmar amber. The new findings suggest that syspastoxyelids were speciose and prosperous in the ecosystem, even though only one family of sawflies, Syspastoxyelidae, has been reported hitherto. [ABSTRACT FROM AUTHOR]

Sedimentary records indicate that subtropical and mid-latitude East Asia exhibited considerable drying and wetting, respectively, during the mid-Cretaceous, which is considered to be relevant to much higher atmospheric carbon dioxide (p CO 2) concentrations and/or proto-Tibetan Plateau (proto-TP) uplift. In order to explore and compare their roles on the East Asian climate evolution, we conducted simulations of the mid-Cretaceous climate system with different atmospheric p CO 2 levels and varying topographies. The results show that both factors had significant influences on the East Asian climate. As the increase in atmospheric p CO 2 levels from ∼560–1120 ppmv to ∼1120–2240 ppmv, the precipitation increases considerably over mid-latitude East Asia, but only small changes in the subtropical portion of East Asia occur. Simultaneously, the effects of the proto-TP uplift are opposite to those of global warming trend during that period. Generally, it leads to a precipitation decrease over subtropical East Asia, but rather minor changes over mid-latitude East Asia. These changes are qualitatively consistent with the deduction based on the geological records, but the magnitudes of the modeled precipitation changes are relatively smaller. Therefore, we can conclude that the subtropical East Asian drying during the mid-Cretaceous can be partly explained by the proto-TP uplift, while the mid-latitude East Asian wetting was partly due to global warming. However, additional factor(s) also played a significant role in the East Asian climate evolution during the mid-Cretaceous. • East Asian climate evolution was dependent on the latitude of the proto-Tibetan Plateau in the deep past; • Global warming induced wetting at mid-latitude East Asian in the mid-Cretaceous; • The proto-Tibetan Plateau uplift led to drying in the subtropical East Asian in the mid-Cretaceous. [ABSTRACT FROM AUTHOR]

The abundance of insects in Burmese amber illustrates a highly diverse insect community of the mid-Cretaceous, but the records of crickets are relatively rare. Here, we erect two new genera with two new species, Birmanioecanthus haplostichus gen. et sp. nov. and Apiculatus cretaceus gen. et sp. nov., based on two new specimens from northern Myanmar amber. These new species can be assigned to the subfamily Oecanthinae (Orthoptera: Gryllidae) by their prognathous head, slender body and metatibiae, and protibiae with large tympana. These new findings are the first and earliest fossil record of tree crickets and shed light on the evolution of Oecanithinae.

The Cretaceous of southern France is characterised by a long erosional hiatus, outlined with bauxite deposits, which represent the only remaining sedimentary record of a key period for geodynamic reconstructions. Detrital zircons from allochthonous karst bauxites of Languedoc (Southern France) have been dated using LA‐ICP‐MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry), in order to specify the age of deposition and to constrain the provenance of the weathered material. We analysed 671 single detrital zircons grains from three karst bauxitic basins, stretching from close to the Variscan Montagne Noire to the present‐day Mediterranean Sea. Analytical results provide Variscan (300–350 Ma) and Late Proterozoic (550–700 Ma) ages as primary groups. In addition, Middle‐, Late Proterozoic and Early Archean (oldest grain at 3.55 Ga) represent significant groups. Mid‐Cretaceous zircons (118–113 Ma) provide a pooled age of 115.5 ± 3.8 Ma, which constitutes the maximum age for bauxite deposition. Results also suggest a dual source for the Languedoc bauxite: one generalised sedimentary source of regional extent and a localised source in the Variscan basement structural high, that has been progressively unroofed during Albian. Integration of these new findings with previously published thermochronological data support the presence of an Early Cretaceous marly cover on the Variscan basement, which has been weathered and then, removed during the Albian. The Languedoc bauxite provide a spatial and temporal link between the uplift of southern French Massif Central to the north, and the Pyrenean rift and its eastward extension to the south. These new results allow to constrain the timing and distribution of uplift/subsidence during the mid‐Cretaceous events in relation with the motion of the Iberian plate relative to Eurasia. [ABSTRACT FROM AUTHOR]

Important geological events that influenced the global environment occurred during the mid‐Cretaceous period. Dramatically increasing temperatures not only triggered oceanic anoxic events (OAEs) but also led to the aridity of terrestrial environments in East Asia. This study provides evidence for the aridity of a terrestrial East Asian environment during the mid‐Cretaceous and provides an example of the influence of the Cretaceous greenhouse climate on a terrestrial lake system in correspondence with the OAE 1a event. Palaeosalinity indexes (B, B/Ga, Sr/Ba, and Couch's palaeosalinity) and palaeoclimate proxies (Sr/Cu, Rb/Sr, Al2O3/MgO, and clay mineral compositions) of shale and mudstone from the Laiyang Group of the Jiaolai Basin in Eastern China were analysed. The results demonstrate that the palaeoclimate in the Wawukuang Formation was relatively warm and humid but became extremely dry and hot in the Shuinan Formation during the OAE 1a event before becoming warm and humid again in the Longwangzhuang and Qugezhuang formations. As a result, the palaeosalinity of the Jiaolai Basin increased from 4% in the Wawukuang Formation to 30% in the Shuinan Formation before decreasing to 0.48% in the Longwangzhuang and Qugezhuang formations. The following conclusions are from combining the distributional characteristics of the saliferous strata and its palaeontology, the palaeogeographic background, and the aeolian sandstone in eastern China. (a) The East Asian continental margin was influenced by the Cretaceous greenhouse climate, which resulted in the salinization of the Jiaolai Basin. (b) The significant increase of the palaeosalinity in the Shuinan Formation was an effect of the OAE 1a event on the terrestrial lake system, which further suggests the OAE 1a event was global. (c) Influences of the hothouse climate on the continental lakes changed the palaeosalinity of the water bodies. [ABSTRACT FROM AUTHOR]

Three new fossil species from Burmese amber are described, one clearly in family Calamoceratidae, the other two in the highly variable family Odontoceridae. The family Odontoceridae contains 18 disparate genera, but there are no good diagnostic characters, which makes it difficult to place fossil taxa in this family. We here offer a revised diagnosis for the family, highlighting the lack of good diagnostic characters, and the need to use sets of characters to place (extinct) taxa in this family. On this taxonomic basis we describe two new species in the hitherto monotypic fossil genus Palaeopsilotreta Wichard & Wang, 2017 (Odontoceridae), Palaeopsilotreta burmanica sp. nov. and P. cretacea sp. nov., redescribe the type species based on additional information, and describe features of the female, based on two specimens, one of which is embedded adjacent to a male identified as P. xiai. Males of Palaeopsilotreta bear bipectinate antennae; the antennae of the females are simple and filiform. Similarly, bipectinate antennae are present in the third species we describe, Bipectinata orientalis gen. et sp. nov., which otherwise lacks the character combinations associated with the Odontoceridae, but clearly can be assigned to the family Calamoceratidae.

A new planktonic foraminiferal species, Hedbergella rhinoceros, from the Late Aptian to the Early Albian sediments of the Marne a Fucoidi formation (Umbro —Marchean Apennines, central Italy) is described and illustrated.

A new genus and species, Burmorussus mirabilis, is described based on two specimens from the mid‐Cretaceous Burmese amber, and considered to be a specialized parasitic wasp of wood‐living hosts. The new taxon is characterized by an orussid‐like ocellar crown, big eyes, antennae attached well above the clypeus, and antennal grooves or ventral transverse frontal carinae absent. Additionally, all legs carry a prominent lanceolate lobe on the third tarsomere. A similar structure is found, but organized differently, in Recent Orussidae and Stephanidae, serving as part of a vibration analyser. Although sharing some characters with families Karatavitidae, Orussidae and Paroryssidae, this new taxon cannot be assigned to any of these families. We propose a new monotypic family Burmorussidae and assign it to the superfamily Orussoidea. A phylogenetic analysis confirms the monophyly of Orussoidea, which occurs a sister group to Apocrita. [ABSTRACT FROM AUTHOR]

Investigation of the ~2400-km-long Tan–Lu Fault Zone (TLFZ) in eastern China is the key to understanding how the Izanagi Plate in the western Pacific Basin and the East Asian continental margin responded to global plate reorganization during the mid-Cretaceous. We present new structural and geochronological data to show that the central segment of the NNE–SSW-striking TLFZ underwent a phase of sinistral transpression after the Early Cretaceous rifting. The resultant strike-slip structures are ductile shear belts in the south of the segment and brittle faults in the north. Quartz c -axis fabrics and other microstructures indicate deformation temperatures of 350–500 °C in different parts of the shear belts. The brittle faults were associated with the formation of NE–SW-trending folds and an angular unconformity between Lower and Upper Cretaceous volcanic or sedimentary rocks. Fault-slip data indicate that sinistral faulting was the result of N S compression. U Pb dating constrains the timing of sinistral faulting between 97 and 82 Ma (early Late Cretaceous). Integration of these and existing data demonstrates that the entire TLFZ underwent sinistral displacement at the beginning of the Late Cretaceous, consistent with continental-scale N S compression in eastern China. Such compression in the overriding plate was caused by rapid oblique subduction of the Izanagi Plate and reflected global plate reorganization at this time. Both the changes in the kinematics of the Izanagi Plate and the resultant variation of stress states in the continental margin around the mid-Cretaceous are ascribed to this plate reorganization. Unlabelled Image • The ~2400-km-long Tan–Lu Fault Zone underwent a phase of sinistral movement between 97 and 82 Ma. • The sinistral faulting indicates continental-scale compression in eastern China. • Both the continental margin and the Pacific Basin record global plate reorganization during the mid-Cretaceous. [ABSTRACT FROM AUTHOR]

A female terrestrial isopod in amber from Myanmar is described as Palaeoarmadillo microsoma gen. et sp. n. (Isopoda: Oniscidea: armadillidae). Placement in the family Armadillidae is based on the 2-segmented flagellum with the flagellum nearly as stout as the basal segments, the head with 2 small medial anterior processes, the fronto-caudally compressed cephalon, the large expanded protopodite with small exopodites dorsally attached and the possibility (based on the shape of the epimera) that the specimen could have formed a global shape. Autapomorphies of the fossil are the shape of the basal antennomeres, flagellum and shape and size of the uropod exopodites. The specimen is parasitized by fly larvae (Diptera) and two mite spermatophores with sperm packets are attached to the dorsum of the isopod. [ABSTRACT FROM AUTHOR]

Burmese amber is an extremely important source of mid-Cretaceous plant and animal remains with over 870 species of organisms, ranging from protozoa to vertebrates, described from this source. The amber mines are located on the West Burma Block that according to geologists was originally part of Gondwana. The present study introduces some angiosperms and insects in Burmese amber whose closest extant relatives have a Gondwanan distribution and there is no previous evidence of a Laurasian distribution. Based on this evidence, it is proposed that organisms in Burmese amber represent a selection of tropical to subtropical life forms that inhabited the interconnected continents of Gondwana in the Early Cretaceous. Based on the fossil record of angiosperms and their diversity in Burmese amber, the West Burma Block could not have rafted from Gondwana to SE Asia before the Early Cretaceous. [ABSTRACT FROM AUTHOR]

The ant-like stone beetle supertribe Mastigitae (Staphylinidae: Scydmaeninae) comprises nine extant and five extinct genera that exhibit unusual morphological specializations and ecological adaptions. Recent discoveries of mastigite fossils from Upper Cretaceous–middle Eocene deposits have significantly improved our knowledge of the evolutionary history of this group, yet a direct fossil record for two modern tribes of unclear affinities, i.e. Leptomastacini and Papusini, is lacking. Herein we describe a new genus and species, †Archemastax divida gen. et sp. nov., based on two well-preserved individuals entombed in mid-Cretaceous Burmese amber (c. 99 Ma), representing the earliest known representative of Leptomastacini. †Archemastax possesses both plesiomorphic and derived characters, with a few important traits shared with extant members of Papusini and Clidicini. A data set of 70 morphological characters scored for 29 species of Mastigitae was analysed using maximum parsimony and Bayesian inference; both analyses recovered a sister relationship between †Archemastax and extant leptomastacines. However, in the former analysis Leptomastacini was recovered as sister to the remaining Mastigitae, while the latter indicated an origin of Leptomastacini from within Clidicini. Although a close affinity between †Archemastax and Papusini was not supported by our analyses, similarities in some shared characters of these two groups are discussed. [ABSTRACT FROM AUTHOR]

Trace fossils, representing ichnospecies Cubiculum ornatus, C. inornatus, Cubiculum isp., and Cuniculichnus variabilis as well as three indeterminate morphological categories (thin branching grooves A and B, furrows and circular chambers), are here recorded on vertebrate remains from the mid-Cretaceous (lower Cenomanian) of the 'Continental Intercalary' deposits in the Gara Samani locality (central Sahara of Algeria). Apart from thin branching grooves (A and B), which are thought to result from root etching, the bioerosion traces recorded on the bones comprise circular chambers and furrows, which represent pupation chambers of scavenging insects, most likely attributed to dermestid beetles. These trace fossils are identified and described for the first time from the Cretaceous of Algeria. They add new data to the trace-fossil assemblages previously reported from other Cretaceous successions of North Africa (e.g., the Kem Kem beds in Morocco). Sedimentological clues indicate a braided fluvial system environment. Taphonomic analysis suggests that the vertebrate remains were most likely subaerially exposed for a prolonged time prior to being transported and finally buried. Therefore, most of the studied borings are likely the result of dermestid beetle larvae feeding on dry bones on dry lands; other borings represent plant etchings produced after the bones were partially covered by, or completely buried, in sediments. [ABSTRACT FROM AUTHOR]

The Cenomanian Mata Amarilla Formation (MAF) in southern Patagonia (~55° S paleolatitude, Austral-Magallanes Basin, Argentina) is composed mainly of stacked fluvial deposits with intercalated paleosols, which document Cenomanian environments at high-paleolatitudes in the Southern Hemisphere. We performed a multiproxy study of the paleosols and sediments of the MAF in order to (1) understand the composition of the soil- and sediment-derived organic matter (OM), (2) apply carbon isotope stratigraphy as a tool to correlate patterns obtained from the MAF with existing marine and non-marine δ13Corg records worldwide, and (3) investigate the relationship between variations in spore-pollen assemblages of the MAF and the climatic conditions prevailing in the Cenomanian Southern Hemisphere. An integrated dataset was generated, including total organic carbon content, Rock-Eval pyrolysis data, stable isotope (δ13Corg) composition, and palynological data, combined with published paleosol-derived mean annual temperatures and mean annual precipitations. The results indicated that the OM preserved in the MAF paleosols allowed its use as a chemostratigraphic tool. The MAF δ13Corg curve showed the rather stable pattern characteristic for the Early to Late Cenomanian interval. The absence of the major positive carbon isotope excursion associated with oceanic anoxic event 2 provided an upper limit for the stratigraphic range of the MAF. The palynological data suggested the development of fern prairies during warmer and moister periods at the expense of the background gymnosperm-dominated forests. Overall, the multiproxy record provided new insights into the long-term environmental conditions during the Cenomanian in the high latitudes of the Southern Hemisphere.

Members of the Larger Benthic Foraminiferal (LBF) family Orbitolinidae occurred from the Cretaceous to the Paleogene, however, they were most diverse during the mid-Cretaceous, and dominated the agglutinated LBF assemblages described from limestones of that period. Various orbitolinid species have been used to zone and date lithologies formed in the shallow, warm waters of the Aptian to the early Cenomanian, and many, sometimes inaccurate, generic and sub-generic nomenclatures have been proposed to differentiate the often-subtle morphological changes that orbitolinids exhibit over time. Also, until now, it has not been possible to develop an effective global overview of their evolution and environmental development because descriptions of specimens from Asia have been relatively rare. Following our recent study of over 1800 orbitolinid-rich thin sections of material from 13 outcrops of Langshan limestone, from the Southern Tibetan Plateau, and from the Barito Basin, South Kalimantan, Indonesia, it has been possible to compare the stratigraphic ranges of these orbitolinids with previously described Tethyan and American forms, based on the use of a planktonic zonal (PZ) scheme, itself tied to the most recent chronostratigraphic scale. This has allowed the reconstruction of the phylogenetic and paleogeographic evolution of the orbitolinids from their Valanginian origin in the Tethys. Although the Tethys remained the paleogeographic centre for the orbitolinids, it is inferred here for the first time that a bi-directional paleogeographic migration of some orbitolinid genera occurred from the Tethys to the Americas and also to the Western Pacific region. Our observations and dating suggest that global marine regressions in the Aptian were coincident with, and may well have facilitated, these orbitolinid transoceanic migrations. Migration stopped however after rising sea level in the early Albian appears to have again isolated these provinces from each other. Tectonic forces associated with the subduction of the Farallon Plate and further sea level raises led to the opening of the Western Interior Seaway in North America, which correlates with, and may have been the cause of, the middle Albian (top of PZ Albian 2) extinction of the American orbitolinids. The extinction of the orbitolinids revealed that the Western Pacific province was split into two sub-provinces, with extinction occurring at the end of the early Albian (top of PZ Albian 1) in the Northwest Pacific sub-province, and at the end of the Albian (top of PZ Albian 4) in the subprovince that is today South East Asia (on the margins and west of the Wallace Line). The final near extinction of the orbitolinids occurred at the end of the Cenomanian in the Tethyan province, which coincides with, and may have been caused by, global anoxic oceanic events that correlate with a near-peak Mesozoic eustatic sea level high-stand that led to the overall global collapse of the paleotropical reef ecosystem at that time.

A new genus and species of moths, Tanyglossus orectometopus n. gen. et sp. (Lepidoptera: Gracillarioidea), is described from mid-Cretaceous Myanmar amber. Autapomorphies for the new genus are small size (body length of only 0.9 mm), long proboscis greater than body length, presence of ocelli, 3-segmented porrect labial palps, 5-segmented curved maxillary palps, no eye cap, lanceolate wings with reduced venation and a body and wing covering of several types of scales. Based on the available characters, the fossil is placed in the small, aberrant family Douglasiidae and represents the first fossil member of this family. This study adds to our scant knowledge of the diversity of Mesozoic Glossata. [ABSTRACT FROM AUTHOR]

Babinskaiidae is an extinct lacewing family of the superfamily Myrmeleontoidea. Hitherto, ten species of seven genera are described from the Lower and mid-Cretaceous periods. Here Pseudoneliana makarkini gen. et sp. nov., a new genus and species of Babinskaiidae from the mid-Cretaceous Burmese amber is characterized, described, illustrated and its taxonomic position discussed. Based on the known palaeo-distribution of the family in Brazil and Myanmar of Gondwanian origin, and Siberia of Laurasian origin, we suggest that this family appeared much earlier than the Barremian period, its oldest fossil record. [ABSTRACT FROM AUTHOR]