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The Maastrichtian-Thanetian Ncham Member of the Aurès Basin in northeastern Algeria contains variably lenticular microfossils, which are defined as Laffitteina genera. It is a large benthic foraminifera, studied from three stratigraphic sections. The systematic study of Laffitteina led identification of nine species, four of which, Laffitteina marsicana, L. aff. mengaudi, L. monodi and L. erki were recorded for the first time in the study area. Various species of Laffitteina were used as index fossils to recognize the K/Pg transition in the Aurès Basin. The last occurrence of L. oztuerki marks the end of the Maastrichtian, which was found in association with Omphalocyclus macroporus (Lamarck) in the upper Maastrichtian. The first occurrence of L. erki marks the Thanetian age, while the Danian and Selandian deposits are missing in the field after a general emersion in the early Paleocene, despite the absence of a visible non unconformity. It could therefore be proposed that the K/Pg transition may occurs in the last 10 m of the Ncham Member. Concerning the paleoenvironment, Laffitteina is considered as a resistant foraminifera and thrives in meso- to eutrophic environments (lagoon). Microfacies data from the Upper Cretaceous-Lower Paleogene limestones of the Aurès Basin suggests a carbonate platform with shallowing-up sequential organization, mainly controlled by fluctuations in sea-level. El Miembro Ncham del Maastrichtiano-Thanetiano de la cuenca de Aurés, en el noreste de Argelia, contiene especímenes variablemente lenticulares, que se definen como del género Laffitteina. Se trata de un gran foraminífero bentónico, estudiado a partir de tres secciones estratigráficas. El estudio sistemático de Laffitteina permitió identificar nueve especies, cuatro de las cuales, Laffitteina marsicana, L. aff. mengaudi, L. monodi y L. erki, se registraron por primera vez en la zona de estudio. Se utilizaron varias especies de Laffitteina como fósiles índice para reconocer la transición K/Pg en la cuenca de Aurés. La última aparición de L. oztuerki marca el final del Maastrichtiano, que se encontró en asociación con Omphalocyclus macroporus (Lamarck) en el Maastrichtiano superior. La primera aparición de L. erki marca la edad del Thanetiense, mientras que los depósitos del Daniano y del Selandiano faltan en el campo tras una emersión general en el Paleoceno temprano, a pesar de la ausencia de un hiato evidente. Por lo tanto, se podría proponer que la transición K/Pg se produce en los últimos 10 m del Miembro Ncham. En cuanto al paleoambiente, Laffitteina se considera un foraminífero resistente y prospera en ambientes de meso a eutróficos (laguna). Los datos de microfacies de las calizas del Cretácico Superior-Paleógeno Inferior de la cuenca de Aurés sugieren una plataforma carbonatada con una organización secuencial ascendente, controlada principalmente por las fluctuaciones del nivel del mar.

Yazdanshahr No.2 section, which consists mostly of Bahram and Sibzar formations is located in the Zarand city, northern Kerman province (Central Iran). Five biozones have been identified based on the conodont community. The first biozone, which includes Padehat (15 meter) and Sibzar formations (75 meter), was distinguished based on genera Bipennatus and Icriodus and the probable corresponding age was considered to span Emsian to Eifelian. The second biozone is recognized by the first appearance of index taxon Polygnathus varcus (varcus Zone: early to middle Givetian). The third biozone starts with the firth appearance of the index genus Icriodus expansus (expansus zone: middle Givetian). The base of the Fourth biozone is recognized by the first appearance of the genus I. subterminus (subterminus Zone: middle to late Givetian) and the last biozone was distinguished with the first appearance of genera Ancyrodella and Polygnathus incompletes in the Givetain-Frasnian boundary (falsiovalis to crepida Zone?: Frasnian to Famenian?). Bahram Formation (94 meter) consists of Fossiliferous limestone (varcus to subterminus Zone) at the lower part, and alternation of dolomite and sandstone (falsiovalis to crepida Zone?) at the upper part. Sibzar Formation consists of Middle Devonian dolomite and limy dolomite containing intercalation of sandstone and limestone layers. La sección Yazdanshahr No.2, que consiste en su mayor parte de las formaciones Bahram y Sibzar, se localiza en la ciudad de Zarand, provincial del norte de Kerman (Irán central). Cinco biozonas han sido identificadas con base en comunidades de conodontos. La primera biozona, que incluye a las formaciones Padehat (15 metros) y Sibzar (75 metros), se distingue con base en la presencia de los géneros Bipennatus and Icriodus, y la edad probable fue considerada en el rango del Emsiano al Eifeliano. La segunda biozona es reconocida por la primera aparición del la especie índice Polygnathus varcus (Zona varcus: Givetiano temprano a medio). La tercer biozona comienza con la primera aparición de la especie índice Icriodus expansus (Zona expansus: Givetiano medio). La base de la cuarta biozona es reconocida por la primera aparición de la especie Icriodus subterminus (Zona subterminus: Givetiano medio a tardío), y la última biozona fue reconocida con la primera aparición de los taxa Ancyrodella y Polygnathus incompletes, en el límite Givetaino-Frasniano (Zona? falsiovalis a crepida: Frasniano a Fameniano?). La Formación Bahram (94 metros) consiste en una caliza fosilífera (Zona varcus a subterminus) en su porción inferior, y de una alternancia de dolomita y arenisca (Zona? falsiovalis a crepida), en su porción superior. La Formación Sibzar consiste de una dolomita de edad Devónico Medio y una dolomita limosa, que contiene una intercalación de capas de arenisca y caliza.

The Cretaceous/Paleogene (K/Pg) Chicxulub impact produced globally synchronous enrichments of highly siderophile elements (HSEs) and a pronounced decline in marine osmium isotope ratios (187Os/188Os), forming a key geochemical marker of the boundary. However, precise identification of the K/Pg boundary remains challenging in extensive pelagic regions dominated by deep‐sea red clay, where calcareous and/or siliceous microfossils are poorly preserved. Here we identify the K/Pg boundary in a pelagic clay sequence from piston core KR13‐02 PC05 recovered near Minamitorishima Island in the western Pacific Ocean using HSE concentrations and Os isotope stratigraphy, supported by ichthyolith biostratigraphy and magnetostratigraphy. A distinct Ir enrichment (up to ∼16 ppb) coincides with the most unradiogenic 187Os/188Os value (∼0.14) at ∼9.95 mbsf, defining a geochemical horizon consistent with the global signature of the Chicxulub impact. Polarity chrons spanning C29n–C30n and ichthyolith assemblages support the placement of the K/Pg boundary and provide a robust chronological framework. Above the boundary, 187Os/188Os ratios remain persistently unradiogenic over a stratigraphic interval corresponding to several hundred thousand years. This prolonged signal reflects the integrated effects of extremely low sedimentation rates, sediment reworking by bioturbation, and background extraterrestrial dust inputs. These results demonstrate that sedimentary Os isotope records in low‐accumulation pelagic clay do not necessarily represent a simple archive of contemporaneous seawater composition. Instead, depositional and diagenetic processes can substantially modify post‐impact isotopic signals. Our findings highlight the necessity of multi‐proxy chronological control and careful geochemical screening when reconstructing oceanic responses to the K/Pg impact on microfossil‐poor pelagic environments.

In this contribution we report the first occurrence of the enigmatic African probainognathian genus Aleodon in the Middle-early Late Triassic of several localities from the state of Rio Grande do Sul in southern Brazil. Aleodon is unusual among early probainognathians in having transversely-expanded postcanine teeth, similar to those of gomphodont cynognathians. This genus was previously known from the Manda Beds of Tanzania and the upper Omingonde Formation of Namibia. The Brazilian record of this genus is based upon multiple specimens representing different ontogenetic stages, including three that were previously referred to the sectorial-toothed probainognathian Chiniquodon theotonicus. We propose a new species of Aleodon (A. cromptoni sp. nov.) based on the specimens from Brazil. Additionally, we tentatively refer one specimen from the upper Omingonde Formation of Namibia to this new taxon, strengthening biostratigraphic correlations between these strata. Inclusion of A. cromptoni in a phylogenetic analysis of eucynodonts recovers it as the sister-taxon of A. brachyrhamphus within the family Chiniquodontidae. The discovery of numerous specimens of Aleodon among the supposedly monospecific Chiniquodon samples of Brazil raises concerns about chiniquodontid alpha taxonomy, particularly given the extremely broad geographic distribution of Chiniquodon. The discovery of Brazilian Aleodon and new records of the traversodontid Luangwa supports the hypothesis that at least two subzones can be recognized in the Dinodontosaurus Assemblage Zone.

A series of global major geological and biological events occurred during the Permian Period. Establishing a highresolution stratigraphic and temporal framework is essential to understand their cause-effect relationship. The official International timescale of the Permian System consists of three series (i.e., Cisuralian, Guadalupian and Lopingian in ascending order) and nine stages. In China, the Permian System is composed of three series (Chuanshanian, Yansingian and Lopingian) and eight stages, of which the subdivisions and definitions of the Chuanshanian and Yangsingian series are very different from the Cisuralian and Guadalupian series. The Permian Period spanned ∼47 Myr. Its base is defined by the First Appearance Datum (FAD) of the conodont Streptognathodus isolatus at Aidaralash, Kazakhstan with an interpolated absolute age 298.9±0.15 Ma at Usolka, southern Urals, Russia. Its top equals the base of the Triassic System and is defined by the FAD of the conodont Hindeodus parvus at Meishan D section, southeast China with an interpolated absolute age 251.902±0.024 Ma. Thirty-five conodont, 23 fusulinid, 17 radiolarian and 20 ammonoid zones are established for the Permian in China, of which the Guadalupian and Lopingian conodont zones have been served as the standard for international correlation. The Permian δ 13 C carb trend indicates that it is characterized by a rapid negative shift of 3–5‰ at the end of the Changhsingian, which can be used for global correlation of the end-Permian mass extinction interval, but δ 13 C carb records from all other intervals may have more or less suffered subsequent diagenetic alteration or represented regional or local signatures only. Permian δ 18 O{ainpatite} studies suggest that an icehouse stage dominated the time interval from the late Carboniferous to Kungurian (late Cisuralian). However, paleoclimate began to ameriolate during the late Kungurian and gradually shifted into a greenhouse-dominated stage during the Guadalupian. The Changhsingian was a relatively cool stage, followed by a globally-recognizable rapid temperature rise of 8–10°C at the very end of the Changhsingian. The 87 Sr/ 86 Sr ratio trend shows that their values at the beginning of the Permian were between 0.70800, then gradually decreased to the late Capitanian minimum 0.70680–0.70690, followed by a persistent increase until the end of the Permian with the value 0.70708. Magenetostratigraphy suggests two distinct stages separated by the Illawarra Reversal in the middle Wordian, of which the lower is the reverse polarity Kiaman Superchron and the upper is the mixed-polarity Illawarra Superchron. The end-Guadalupian (or pre-Lopingian) biological crisis occurred during the late Capitanian, when faunal changeovers of different fossil groups had different paces, but generally experienced a relatively long time from the Jinogondolella altudensis Zone until the earliest Wuchiapingian. The end-Permian mass extinction was a catastrophic event that is best constrained at the Meishan section, which occurred at 251.941±0.037 Ma and persisted no more than 61±48 kyr. After the major pulse at Bed 25, the extinction patterns are displayed differently in different sections. The global end-Guadalupian regression is manifested between the conodont Jinogondolella xuanhanensis and Clarkina dukouensis zones and the end-Changhsingian transgression began in the Hindeodus changxingensis-Clarkina zhejiangensis Zone. The Permian Period is also characterized by strong faunal provincialism in general, which resulted in difficulties in inter-continental and inter-regional correlation of both marine and terrestrial systems.

Benthic foraminiferal assemblages dominated by Alveolina species from the Ypresian (Ilerdian–Cuisian) are studied herein from numerous localities of Iran and Turkey. From these successions, highly diversified assemblage of 58 alveolinid species are identified along with their detailed biostratigraphical application, which resulted in the recognition of eight shallow benthic zones (SBZ5–SBZ12). Our findings are based upon the distribution ranges of Alveolina from the Ilerdian–Cuisian sediments in Iran (Central Tethys) that are considered to have a strong affinity with their coeval fauna in Turkey (Western Tethys). In this study, the wide expansion ranges of Alveolina permit us to achieve a high-resolution biostratigraphy and apply the shallow benthic zones of the peri-Mediterranean region (Western Tethys) to the Ilerdian–Cuisian successions in Iran (Central Tethys). Nevertheless, the distribution of some Alveolina species, even the zonalmarkers consisting of Glomalveolina lepidula, Alveolina ellipsoidalis, A. pisiformis, A. laxa, A. subpyrenaica, A. varians, A. fornasinii and A. canavarii are found occurring at younger stratigraphic levels in Iran and/or Turkey than in thewestern European shallow marine deposits.

A systematic description of the Eocene larger foraminifera recorded in the South Pyrenean Basin (Sierras Exteriores) is presented herein. The large dataset provided in this work includes Nummulites and Alveolina species, along with a variety of other porcellaneous and hyaline taxa with lesser biostratigraphic relevance. Most of the larger foraminifera described in this work correspond to the Lutetian (SBZ13 to SBZ16 biozones) interval, but late Ypresian (SBZ11, Cuisian) and early Bartonian (SBZ17) shallow benthic zones have also been identified. A new species, Idalinaosquetaensis, is described. The systematic revision of middle to late Lutetian alveolines led to a reassessment of Alveolinafusiformis and the finding of two new precursor forms, described as Alveolina aff. fragilis and Alveolina aff. elongata. The new taxa fill in the gap existing so far in the middle to late Lutetian alveolinid biostratigraphy. Despite not being exclusive to SBZ16, these forms provide realiable biostratigraphic information in facies where Nummulites are not present. This realibility lies on the correlation of Nummulitesand Alveolina biostratigraphic markers in the same sections and their calibration to the global time scale through magnetostratigraphy. Magnetostratigraphic calibration of described taxa is provided, along with an update of the SBZ calibration to the Geological Time Scale (Gradstein et al., 2012). .

An Ordovician depositional hiatus spanning the middle Floian to lower Darriwilian, estimated to represent a period of at least 3 Myr, is confirmed for the first time in the Taebaek Group, Korea, based on integrated conodont biostratigraphic and sedimentologic data. The conodont biozones of the uppermost Dumugol and lower Makgol formations are revised and redefined with presentation of a new biozonal framework, which contains, the Serratognathus bilobatus Biozone, the Serratognathus extensus Biozone, the Paraserratognathus obesus Biozone, and the Tangshanodus tangshanensis Biozone in ascending order. The hiatus lies within the barren interval between the middle Floian Paraserratognathus obesus Biozone and the early Darriwilian Tangshanodus tangshanensis Biozone. The unconformity surface is located at the boundary between the basal and lower members of the Makgol Formation, 1.5 meters above the base of the barren interval, on the basis of sedimentary evidence such as differences in the depositional and diagenetic features as well as a sharp contact between the two members with subaerial exposure feature including vuggy to channel pore and dolostone breccia. The barren interval above the hiatus is considered due to environmental factor: the peritidal condition is regarded unfavorable for inhabitation of conodont animals. The newly established Floian and Darriwilian conodont biozones and depositional hiatus within the lower Makgol Formation indicate that the Ordovician succession of the Taebaek Group is essentially an extension of that of the North China Block.

Guided by conodont biostratigraphy and unconformities observed in the field, stable carbon isotopic analysis (δ13Ccarb) was performed on 210 samples from Lower–Middle Ordovician (Tremadocian to Darriwilian) sections and wells in the Tarim Basin, NW China. The δ13C trend in the Tarim Basin sections has three distinct characteristics: (1) from the Tremadocian to the Floian, a positive shift from −1.9 ‰ to −0.2 ‰ is observed near the boundary between the Penglaiba Formation and the Yingshan Formation; (2) from the Floian to the Dapingian, a positive shift in δ13C from −3 ‰ to −0.7 ‰ occurred under large-scale sea-level rise and a change in the sedimentary environment from a restricted platform to an open platform. Changes in the conodont type are also observed in the Tabei region; and (3) from the Dapingian to the Darriwilian, δ13C first decreased and then increased, showing a negative shift at the Dapingian–Darriwilian boundary. During the Floian, δ13C decreased in the study area, while it first decreased and then increased in other regions, which may reflect local sea-level movements in response to isostatic crustal movements. Two types of positive shift were identified at the Floian–Dapingian boundary, which likely show the effects of local factors, including a disconformity, dolomitization, and platform restriction, superimposed on the global signal of the carbon isotope. Some conodont zonations and recurrent negative excursions in Tremadocian, Floian and Dapingian stages appear to be truncated by unconformities, which are accompanied by short-term subaerial exposure due to sea-level fall and local tectonic uplift.