Aptian Albian Research Articles

A new neoceratopsian (Ornithischia, Ceratopsia) from the Lower Cretaceous Ohyamashimo Formation (Albian), southwestern Japan

AbstractThe herbivorous dinosaur clade Ceratopsia flourished in the northern hemisphere during the Late Jurassic to Late Cretaceous. Previous palaeobiogeographic studies have suggested that their initial diversification occurred in Asia, with early‐branching neoceratopsians extending their geographical range to North America sometime during the Barremian to Albian. However, the specific timing and mode of their dispersal from Asia to North America remains unknown. Here we describe a new, early‐branching neoceratopsian, Sasayamagnomus saegusai gen. et sp. nov., from the Albian Ohyamashimo Formation in southwestern Japan, representing the easternmost fossil record of ceratopsians in Asia. Sasayamagnomus exhibits three diagnostic features in the jugal, squamosal and coracoid, respectively, and also has a unique combination of characters in the lacrimal. Our phylogenetic analysis indicates that Sasayamagnomus forms a clade with Aquilops americanus, one of the earliest neoceratopsians from North America, followed by the sister taxon Auroraceratops rugosus from China. The present time‐calibrated phylogenetic tree indicates that the immigration of neoceratopsians from Asia to North America occurred during the latest Aptian or early Albian, refining the previously suggested timeframe. This aligns with fragmentary neoceratopsian fossil records from the Lower Cretaceous of North America and the initial formation of the Bering land bridge. Furthermore, the simultaneous occurrence of global warming (which enabled the development of extensive forests in the Arctic region) and the emergence of the Bering land bridge during the Aptian–Albian, probably played a crucial role in facilitating the immigration of neoceratopsians from Asia to North America.

New Early Cretaceous zalambdalestid stem placental mammal from Mongolia and evolution of Zalambdalestidae

ABSTRACT Prozalambdalestes cratodus gen. et sp. nov. is based on a fragmentary dentary from the Lower Cretaceous (Aptian–Albian) Khovoor locality in Gobi Desert, Mongolia. This is the largest eutherian in the Khovoor mammal assemblage. It shows dental specializations of Zalambdalestidae such as procumbent, ever-growing gliriform first lower incisor with restricted enamel and reaching posteriorly p5, and mesiodistally compressed lower molar trigonids. The enamel is restricted to the ventrolabial and ventrolingual sides of the mesial half of the incisor and the enamel band is higher on the labial side. The new taxon retains five lower premolars, with p1 smaller than p2 and p3 smaller than adjacent premolars, and the Meckelian groove. It also differs from other zalambdalestids by position of mental foramina (under p3 and p5), p1–3 obliquely set in dentary, and lower molar talonids wider than trigonids. Phylogenetic analysis places Prozalambdalestes gen. nov. in a polytomy with Albian Zhangolestes, Turonian Kulbeckia, and the clade of Campanian zalambdalestids from Mongolia and Kazakhstan. CT data in Zalambdalestes and comparison with Prozalambdalestes gen. nov. show that the four lower premolars in Zalambdalestes are p2, p3 (variable present), p4, and p5. Consequently, the three lower premolars of Barunlestes and Zofialestes are p2, p4, and p5. The other diagnostic characters of Zalambdalestidae are reviewed.

A mid-Cretaceous carbon isotope reference curve for the SE Neo-Tethys region (Zagros, W Iran)

Stable carbon isotope chemostratigraphy and the associated reference curves have proved to be valuable tools for stratigraphic calibration and long-distance correlations. Nonetheless, the reference curves covering the Cretaceous have mostly been produced from localities located within the W Neo-Tethys. In order to establish a reference curve for the SE Neo-Tethys margin, an Aptian–Albian hemipelagic carbonate-rich succession deposited along the Zagros Basin (SW Iran) was examined for planktic foraminifera biostratigraphy, carbon isotope stratigraphy, and sedimentological characteristics. Eight biozones including Globigerinelloides ferreolensis, Globigerinelloides algerianus, Hedbergella trocoidea, Paraticinella bejaouaensis, Muricohedbergella planispira, Ticinella (T.) primula, Biticinella breggiensis, and Pseudothalmanninella (P.)ticinensis as well as two subzones enclosing T. praeticinensis and P. subticinensis assign the strata to the early late Aptian–late Albian age. A carbon isotope record constrained by the planktic foraminifera zonation scheme shows good concordance with existing composite reference curves from the W Neo-Tethys region. Several carbon isotope excursions (CIEs) characterizing global marine events including Oceanic Anoxic Event (OAE) 1a, OAE1b, OAE1c and associated sub-events can be identified in the studied section. Deoxygenated bottom waters associated with the formation of OAE1a and OAE1b are indicated by distinct lithological signatures including enrichment in pyrite and glauconite, nodular and stratiform chert beds, as well as enhanced organic matter contents. We integrate the here-studied interval with a previously published upper Albian−Turonian succession from the same outcrop section, forming a composite, stratigraphically well-constrained section. This results in a high-resolution carbon isotope record for the SE Neo-Tethys margin, considered to represent an expedient reference Aptian–Turonian curve for this region. Correlation of this new curve with previously published records from the Middle East has helped to address ambiguities regarding the stratigraphic positions of the early/late Aptian and Aptian/Albian boundaries identified by previous studies.

New record of Brachyoxylon wood from the Lower Cretaceous of Qingyuan, southeastern China and its palaeoclimatic implications

Early Cretaceous was a key period for the evolution of terrestrial ecosystems. In southeastern China, the late Early Cretaceous (Aptian–Albian) floras are relatively well known and characterized by diverse Cheirolepidiaceae, but the early Early Cretaceous floras in southeastern China are poorly known mainly because of the lack of plant fossils. Here we report petrified woods from a new early Early Cretaceous locality in Qingyuan, southern Zhejiang Province, southeastern China. The new fossil woods collected from the Xishantou Formation (earliest Berriasian, earliest Early Cretaceous) are assigned to Brachyoxylon zhejiangense Tian, Zhu, and Wang based on the anatomy of the secondary xylem. The new material of Brachyoxylon zhejiangense from Qingyuan lacks distinct growth rings or resin canals and has mixed type pitting on the radial walls of the tracheids, araucarioid cross-field pitting, and uniseriate rays. It is the earliest record of Brachyoxylon in southeastern China. Brachyoxylon zhejiangense has been regarded as the wood of the extinct conifer family Cheirolepidiceae and grew in arid to semi-arid environments. Evidence also suggests Cheirolepidiaceae played an important role in the vegetation of southeastern China throughout the Early Cretaceous.

Molecular fossils of Aptian–Albian blue marls of the Vocontian Basin (France), depositional conditions and connections to the Tethys Ocean

Molecular fossils of Aptian–Albian blue marls of the Vocontian Basin (France), depositional conditions and connections to the Tethys Ocean

Comments on « Environmental and climatic controls of the clay mineralogy of Albian deposits in the Paris and Vocontian basins (France) » [Cretaceous Res. 108 (2020) 104342] and « Astronomical calibration of the OAE1b from the Col de Pré-Guittard section (Aptian-Albian) Vocontian Basin » [Cretaceous Res. 150 (2023) 105618

We wish to point out an obvious error made by one of us (J.F. Deconinck), and kindly reported by J.G. Bréhéret, the reason why we have jointly decided to publish this correction. The error affects at varying degrees the scientific quality and partly invalidates the conclusions of the following articles: Corentin et al. (2020) « Environmental and climatic controls of the clay mineralogy of Albian deposits in the Paris and Vocontian basins (France) » (Cretaceous Research, 108). and Ait-Itto et al. (2023) « Astronomical calibration of the OAE1b from the Col de Pré-Guittard section (Aptian–Albian) Vocontian Basin » (Cretaceous Research, 150).Indeed, for the Vocontian basin, the analytical work, whatever its quality, was carried out on a stratigraphic interval which does not correspond to the presentation made. The two articles in question did not take into account the detailed lithostratigraphy and biostratigraphy earlier published, notably by Bréhéret (1997) and Bréhéret & Brumsack (2000) mentioning known marker beds as presented in these works. Thus, for one of the two sections, the displayed time window assumed to be the lower Albian, actually corresponds to a small part of the middle Albian and a part of the upper Albian. This invalidates many of the proposed results and conclusions.

Calcareous nannofossils from the Poggio le Guaine core (Umbria-Marche Basin, central Italy): Biostratigraphy and discussion of Aptian–Albian bioevents.

Calcareous nannofossils from the Poggio le Guaine core (Umbria-Marche Basin, central Italy): Biostratigraphy and discussion of Aptian–Albian bioevents.

Aptian–Albian calcareous nannofossils from the South Atlantic Ocean: Implications for paleoclimate and paleogeography.

Aptian–Albian calcareous nannofossils from the South Atlantic Ocean: Implications for paleoclimate and paleogeography.

Aptian–Albian sequence stratigraphy, biostratigraphy, chemostratigraphy, and chronostratigraphy: Sonoran shelf and Tamaulipas Basin, Mexico

The Late Jurassic extensional Bisbee Basin in northwestern Mexico and southwestern United States lay between the Pacific magmatic arc and subduction zone and the cratonic Comanche shelf. Aptian to late Albian fluvial, deltaic, and shallow marine sediments and patch reefs of the Bisbee Group filled the basin. The upper Barremian(?)–lower Aptian Cerro de Oro Formation and its equivalent Rancho La Colgada Formation are overlain by the Morita, Mural, Cintura, and La Juana formations. The paralic Morita Formation and the marine Mural Limestone grade southeast into the marine Agua Salada and Lampazos formations, which correlate with deep-water facies in the Chihuahua trough and Tamaulipas Basin. Three late Aptian to middle Albian long-term depositional cycles were approximately 2.5 myr in duration.Foraminifers, calcareous algae, bivalves, rudists, corals, dinoflagellates and scarce ammonites compose the Mural Limestone biostratigraphy. First-occurrence datums of Aptian–Albian benthic Foraminifera are integrated with planktonic Foraminifera and rudists and define biostratigraphic zones that correlate with the Comanche shelf. In the Chihuahua trough and Tamaulipas Basin planktonic Foraminifera and nannofossils identify global zones. Stage boundaries on the Sonora shelf are correlated by a comprehensive biostratigraphic database.Carbon isotope chemozones correlate with Tethyan chemostratigraphy. The lower Aptian OAE 1a and uppermost Aptian–lowest Albian OAE1b chemozone are in the Lampazos section. The negative δ13C excursions and fossil evidence correlate with global Jacob, Kilian, Paquier, and Leenhardt levels. Low-oxygen water masses flooded the shallow shelf and even affected coral-rudist buildups.

Microfacies analysis and paleoenvironmental interpretation of the late Aptian–Albian (Early Cretaceous) carbonates of the Riachuelo Formation in the Sergipe Sub-basin, northeastern Brazil

The beginning of the drift phase, in the Aptian–Albian transition, marked the development of marine conditions in the South Atlantic Ocean, characterized by the deposition of evaporites, followed by the development of carbonate platforms. The carbonate rocks of this interval were deposited in a passive margin context as part of the Riachuelo Formation in the Sergipe-Alagoas Basin, northeastern Brazil. The objective of present study was to analyze the microfacies of the Aptian–Albian interval in the northern portion of Sergipe State, near the city of Pacatuba. The mainly carbonates of two cores were investigated and five carbonate microfacies were identified: oncoidal rudstone, bioclastic rudstone, oncoidal packstone, peloidal packstone/wackestone, and mudstone with planktonic bioelements that suggest the paleoenvironments were relatively shallow marine. The microfacies were dominated by oncoids in almost every sample, which occurred in association with stromatolites. The biostratigraphic results were based on palynomorphs and calcareous nannofossils. The palynomorphs assemblages indicated a late Aptian age. Paleoecological results of these fossil groups show paleoenvironmental conditions of the shallow waters with proximal characteristics, with the predominance of pollens and spores associated with rare dinoflagellates and ascidians. A striking feature was the presence of authigenic glauconite which filled skeletal cavities and partially replaced the oncoids and their nuclei, mostly in the oncoidal packstone facies. Together, these findings suggest that the samples formed at the basal portion of the Riachuelo Formation in a transgressive systems tract, corresponding to the first depositional stage of the Riachuelo Formation.

Wing phalanges of a ?thalassodromine pterosaur from the Aptian–Albian Antlers Formation of Texas, USA

Fragmentary pterosaurian wing phalanges from the Aptian-Albian Antlers Formation of north-central Texas, USA are described. Wing phalanges 1 and 2 have suboval shafts with thickened bone at the leading and trailing edges, whereas the third wing phalanx has a flattened airfoil-like cross-section with greatly thickened bone at the leading and trailing edges and a small subrectangular medullary cavity. The cortical bone exhibits an unusual coarse surface texture, and bone thin sections reveal extensive Haversian remodeling and endosteal lamellar bone. The morphology of the wing phalanges differs from that of dsungaripterids, pteranodontoids, and azhdarchids, so the specimen is not a North American record of the Dsungaripteridae as some have stated; whereas based on comparisons to a roughly contemporaneous indeterminate thalassodromine pterosaur specimen from the Romualdo Formation of Brazil, the specimen is tentatively interpreted as an indeterminate thalassodromine with an estimated wingspan of ∼3.5 m.

Aptian–Albian Oysters from the Southwestern Spurs of the Gissar Ridge. Part 3. Genus Oscillopha Malchus

Aptian–Albian Oysters from the Southwestern Spurs of the Gissar Ridge. Part 3. Genus Oscillopha Malchus

Critical revision and new proposals on the Aptian–Albian zonation of the Standard Mediterranean Ammonite Zonal Scheme

Critical revision and new proposals on the Aptian–Albian zonation of the Standard Mediterranean Ammonite Zonal Scheme

Insect herbivory on early angiosperms from the lower cretaceous of Northwest China

ABSTRACT Insect herbivory on fossil angiosperm leaves was recorded from the upper Lower Cretaceous Zhonggou Formation in the Hanxia Section of the Jiuquan Basin, Gansu Province, NW China. Four functional feeding groups, including hole feeding, margin feeding, skeletonisation, and galling were recognised on nine fossil angiosperm leaves belonging to three species of eudicot. Ten insect damage types (DTs), including DT01, DT02, DT03, DT12, DT14, DT15, DT26, DT32, DT34, and DT61, were identified based on the insect damage morphotypes. Combined with the fossil records of insects reported from the Lower Cretaceous Zhonggou Formation of Jiuquan Basin, these suggest that there were various herbivorous insects that are related to the insect DTs, such as Blattoidea, Hemiptera, Diptera, Orthoptera, and Coleopterathe, which can related to the insects DTs, and indicate a diversified herbivorous insectangiosperm community in Jiuquan Basin during the late Early Cretaceous. Moreover, the diversified terrestrial ecosystem and fluctuating wet and dry climate in Jiuquan Basin during the late Early Cretaceous, would provide a suitable condition for the radiation of herbaceous angiosperms in Jiuquan Basin during the Aptian–Albian gap and promoting the coevolution of early angiosperms and their related herbivores.

New theropod dinosaur from the Lower Cretaceous of Japan provides critical implications for the early evolution of ornithomimosaurs

Ornithomimosauria consists of the ostrich-mimic dinosaurs, most of which showing cursorial adaptations, that often exhibit features indicative of herbivory. Recent discoveries have greatly improved our knowledge of their evolutionary history, including the divergence into Ornithomimidae and Deinocheiridae in the Early Cretaceous, but the early part of their history remains obscured because their fossil remains are scarce in the Aptian–Albian sediments. In recent years, many isolated ornithomimosaur remains have been recovered from the Aptian Kitadani Formation of Fukui, central Japan. These remains represent multiple individuals that share some morphological features common to them but unknown in other ornithomimosaurs, suggesting a monospecific accumulation of a new taxon. As a result of the description and phylogenetic analysis, the Kitadani ornithomimosaur is recovered as a new genus and species Tyrannomimus fukuiensis, the earliest definitive deinocheirid that complements our knowledge to understand the early evolutionary history of Ornithomimosauria. Due to its osteological similarity to Tyrannomimus, a taxon previously considered an early tyrannosauroid based on fragmentary specimens, namely Aviatyrannis jurassica, may represent the earliest ornithomimosaur from the Upper Jurassic of Europe, significantly expanding the temporal and biogeographic range of Ornithomimosauria. This finding fills a 20-million-year ghost lineage of Ornithomimosauria implied by the presence of the oldest fossil record of Maniraptora from the Middle Jurassic and is consistent with the hypothesis that their biogeographic range was widespread before the Pangaean breakup in the Kimmeridgian.

Aptian–Albian Oysters from the Southwestern Spurs of the Gissar Ridge. Part 3. Genus <i>Oscillopha</i> Malchus

Representatives of the genus Oscillopha Malchus, 1990 from the Aptian, Albian and Cenomanian of the southwestern spurs of the Gissar Ridge (southeastern Turkmenistan) are revised. Questions of taxonomy of Mesozoic Lopha-like oysters are discussed. The diagnoses and composition of the family Arctostreidae Vialov, 1983, the subfamily Arctostreinae Vialov, 1983 and the genus Oscillopha Malchus, 1990 are specified. In the Aptian and Albian, the genus Oscillopha is represented by the species O. eos (Coquand, 1869) and in the Cenomanian—by the species O. dichotoma (Bayle, 1849).

A first high-resolution carbon isotope stratigraphy from the Boreal (NW Germany) for the Berriasian to Coniacian interval—implications for the timing of the Aptian–Albian boundary

High-amplitude changes in sedimentary δ13C characterize the Cretaceous system and have been proven useful for supra-regional chemostratigraphic correlation. In the Cretaceous, these δ13C perturbations indicate large shifts between the global carbon reservoirs that are usually caused by volcanic activity of large igneous provinces, the widespread deposition of thick organic carbon-rich sequences and/or changes in orbital parameters. Here, we present an upper Berriasian to lower Coniacian (c. 142–88 Ma) composite carbon isotope record based on 14 drill cores, 2 outcrops, and almost 5,000 samples. The total record comprises a composite thickness of more than 1,500 m. All cores and successions are located in the larger Hanover area, which represents the depocenter of the North German Lower Saxony Basin in Early to mid-Cretaceous times. In Northern Germany, Boreal Lower Cretaceous sediments are predominantly represented by CaCO3-poor mud and siltstones of up to 2,000 m thickness, which become more carbonate-rich during the Albian–Cenomanian transition and even chalkier in the upper Cenomanian to Coniacian interval. The carbon isotope record reveals a number of global key events, including the Valanginian Weissert Event, the Oceanic Anoxic Events (OAEs) 1a and d, and the Kilian Event (Aptian–Albian boundary, part of OAE 1b). For the early Late Cretaceous, the Mid-Cenomanian Event, the OAE 2 (Cenomanian–Turonian Boundary Event), and the Navigation Event, among others, have been identified. The Kilian Event represents the Aptian–Albian boundary and has been identified herein for the first time in Northern Europe. Based on the evaluation of its relative position to the Vöhrum boundary tuff, we tentatively propose a slightly older age for the Aptian–Albian boundary of c. 113.65 Ma instead of 113.2 Ma. The observed chemostratigraphic events enable a detailed stratigraphic comparison with Tethyan and other Boreal records and associated paleoenvironmental data. Thus, this new detailed chemostratigraphy provides a unique opportunity to potentially overcome many still existing Boreal–Tethyan correlation issues. The presented record can be considered almost complete, albeit a 2-Myr gap during the early Albian is likely, and condensed intervals occur specifically during the lower Aptian.

Astronomical calibration of the OAE1b from the Col de Pré-Guittard section (Aptian–Albian), Vocontian Basin, France

A high-resolution spectral analysis was performed on magnetic susceptibility (MS) in the Col de Pré-Guittard section (CPG), Vocontian Basin, France to provide a new astronomical time scale of the Aptian–Albian transition and to explore the link between Milankovitch cycles and the occurrence of four laminated black shales events, namely Jacob, Kilian, Paquier and Leenhardt constituting the OAE 1b. The spectral analysis performed on the CPG section records the imprint of a strong predominance of the precession, and 100-kyr and 405-kyr eccentricity cycles. Based on the number of 405-kyr eccentricity cycles, the duration of the interval encompassing the Jacob to Leenhardt levels is calculated at 4.03 myr. The duration between Jacob, Kilian, Paquier and Leenhardt Events are respectively calculated at 1.55 myr, 1.62 myr, and 0.93 myr. The duration calculated for the occurrence of these events is not related to the Milankovitch cycles. However, these events are recorded near local maxima of the 405-kyr filter. Our results show that the 405-kyr eccentricity impacted the recurrence of anoxic levels in the Vocontian Basin, although additional factors, such as the emplacement of flood basalts or oceanic basaltic plateaus have contributed to the development of larger scale marine anoxia.

New planktonic foraminiferal record across the Aptian–Albian transition in Interior Fars, Zagros Basin, SW Iran: Implication for latest Aptian paleogeography along the southern shallower Neo-Tethys

The Aptian–Albian (A–A) transition encompassed a critical timing in the evolution of Fars Platform (Zagros Basin, SW Iran), such that a number of previous studies on its proximal part (called “Coastal Fars”) illustrated platform recovery after sustained demise due to latest Aptian maximum sea-level lowstand. So far, much less attention has been given to the distal part of the platform – “Interior Fars” – where the lack of proper geological age interpretations, in particular, has been limiting a full paleoenvironmental reconstruction of the southern shallower Neo-Tethys. In order to establish the chronostratigraphic framework of Interior Fars, this study presents a novel set of planktonic foraminiferal record for the A–A Kazhdumi Formation at the Saroie section. The identified fauna comprises nine species from four genera, all of which are reported for the first time from Fars Platform. The observed new bioevents are generally consistent with those of the proposed reference section at a deeper intrashelf setting (Tang-e-Maghar, Dezful Embayment), allowing for the establishment of a local upper Aptian–Lower Albian zonation and leading to adequate constraints on the local Aptian/Albian boundary and the timing of prominent black shale deposition (possible “Jacob” equivalent). Based on this new Saroie chronostratigraphic scheme, it is evident that sedimentation across the A–A transition was maintained fully marine at the Saroie section, Interior Fars. This finding does not support the previous inference of extensive subaerial exposure of the entire Fars Platform at that time, thereby calling for a major revision of the published prevailing model for latest Aptian paleogeography of this region. These new insights will facilitate better understanding of the Fars Platform evolution in the Zagros Basin as well as paleoenvironmental reconstructions along the southern Neo-Tethys.

Aptian–Albian shallow-marine carbonate successions of the Geyik Dağı and the Anamas Dağ areas (Central Taurides, Turkey): Benthic foraminiferal assemblages and “Palaeocornuloculina” taurica nov. sp. (Foraminifera)

The Lower Cretaceous carbonate successions of the Tauride Carbonate Platform(s) (TCP) are characterized by mostly restricted inner platform facies. The record of these stages is limited owing to frequent exposure of the platform to subaerial and supratidal settings during the Early Cretaceous. This study focuses on the Lower Cretaceous (Aptian–Albian) successions outcropping at two localities in the Geyik Dağı and Anamas Dağ areas, Central Taurides. These successions exhibit a peritidal shallowing upward trend evidenced by the dominance of mud-rich microfacies, lamination, fenestrae, oncoids, and changes in fossil content (benthic foraminifera, dasycladalean algae, rudists, etc.). The stratigraphic subdivisions of the studied successions utilize index taxa in the benthic foraminiferal assemblages which are documented and illustrated. Assemblage I (lower Aptian) is mainly characterized by Voloshinoides murgensis and Debarina hahounerensis; Assemblage II (upper Aptian) by Mesorbitolina parva, Carseyella tunesiana and “Arenobulimina” geyikensis; and Assemblage III (Albian) by Mesorbitolina gr. texana, Protochrysalidina elongata and Pseudonummoloculina heimi. Ranges and stratigraphic significance of some species through the Lower Cretaceous are discussed. Due to less favorable environmental conditions, the strata in the Anamas Dağ area have a low-diversity benthic foraminifera fauna and sparse macrofossils. In contrast, the strata in the Geyik Dağı area host rich and diverse larger benthic foraminifera as well as rudist bivalves and gastropods. A new species, “Palaeocornuloculina” taurica belonging to the family Ophthalmidiidae is described from these foraminifera-rich upper Aptian–Albian strata in the Geyik Dağı area.