Jurassic system stratigraphy at the Kamianka village. Part 3. The Pidluzhna formation

Introduction. The paper is devoted to the study of the Pidluzhna Formation of the Jurassic system of the North-Western outskirts of the Donetsk folded structure and is a continuation of a series of publications highlighting the stratigraphy of Jurassic deposits in key areas near the town of Izyum and the village of Kamianka. Analysis of previous publications. The Pidluzhna Formation was first identified by L.F. Lungershausen in 1941, he noted the homogeneity of the lithological composition and the somewhat different nature of the sediments in the zones of relative uplift and subsidence. Later, these deposits were not considered in the rank of Formation, but were attributed to the Upper Bajoсian - Lower Bathonian. Material and methods. The Pidluzhna Formation is widespread in the Kamianskaya area. Since the deposits are composed mainly of clays, there are no more or less significant outcrops of it. The scientific search was based on the analysis of literature, results of previous drilling and mapping works, as well as own field, laboratory and analytical studies. Micropaleontological analysis and generalized data on the distribution of fossil remains were carried out. The palynological analysis of these deposits was also carried out, namely, stratified deposits with the help of microphytofossils. Results and discussion. Since the stratotype of the Pidluzhna Formation has not been precisely specified and currently the stratotype area is under urban development and only its small fragments are exposed, it is possible to propose as a neostratotype the outcrop of this Formation near the village of Sukha Kamyanka, in a ravine that extends north parallel to the Sukha Kamyanka - Yaremivka road. Lithology. The lithological composition of the Pidluzhna Formation was studied in detail by G.V. Karpova and V.G. Kosmachev. The main, clayey, part of the formation is composed of hydromicas with a slight admixture of montmorillonite group minerals and kaolin. Paleontological remains and Stratigraphy. This work summarizes previous paleontological data of scientists and supplements them with their own research. In general, these are brachiopods, cephalopods, gastropods, bivalves, malacostraca, ostracods, foraminifera, wood cuticles and tracheids, remains of prasinophyte and dinophyte algae, acritarchs, and spores and pollen of higher plants. Paleontological remains, including leading ammonite species, are found in the Pidluzhna Formation quite often. In the lower part of the Formation (Bajoсian) - the Garantiana garanti and Parkinsonia parkinsoni zones stand out, in the upper part (Bathonian) - lones of the Pseudocosmoceras michalskii. According to the data of palynological analysis, the conclusions regarding the age of the sediments of the Pidluzhna Formation are confirmed. A characteristic feature, namely the Bajoсian, is the dominance of fern-like Dictyophyllidites and the appearance of spores of Neoraistrickia rotundiformis, Duplexisporites anagrammensis, Converrucosisporites disparituberculatus, Laevigatosporites ovatus, Leptolepidites major, Densoisporites velatus and pollen of gymnosperms Callialasporites dampieri, Araucariacites australis, Vitreisporites pallidus. Foveosporites, Klukisporites, Lycopodiacidites and Uvaesporites, as well as fern-like Clathropteris obovata var. magna and the dominance of Concavisporites distinguishes the Bathonian deposits, which we observe in the Kamianka sections.Стаття присвячена дослідженню підлужної світи юрської системи Північно-Західної околиці Донецької складчастої споруди. Встановлений її речовинний склад та особливості його зміни по розрізу та по площі в межах околиць с. Кам’янка, щона південній Ізюмщині. Дослідження включало аналіз літературних даних та результатів картування, а також власні спостереження. Проведено палеонтологічний, в тому числі вперше детальний палінологічний аналізи, та узагальнені дані про поширення всіх викопних решток, що були встановлені в підлужній світі. В статті зведені всі попередні палеонтологічні дані науковців та доповнено власними дослідженнями. Загалом це – брахіоподи, головоногі молюски, черевоногі молюски, двостулкові молюски, малакостраки, остракоди, форамініфери, кутикули та трахеїди деревини, рештки празинофітових та динофітових водоростей, акритархи та спори і пилок вищих рослин. Підлужна світа, в межах дослідженої території, представленадосить одноманітними глинами. Глини гідрослюдисті з незначною домішкою монтморіллоніту та каоліну. Колір глин темносірий місцями з блакитним відтінком. Глини містять карбонатні (сидеритові та кальцитові) конкреції. Палеонтологічні залишки зустрічаються часто і по всьому розрізу світи. Представлені морськими групами, в тому числі важливими з точки зорустратиграфії. Встановлені зони за амонітами Garantiana garanti, Parkinsonia parkinsoni та лона Pseudocosmoceras michalskii,що дозволяє впевнено датувати відклади верхнім байосом – нижнім батом. Характерною ознакою байосу є домінування папоротеподібних Dictyophyllidites та поява Neoraistrickia rotundiformis, Duplexisporites anagrammensis, Converrucosisporitesdisparituberculatus, Laevigatosporites ovatus, Leptolepidites major, Densoisporites velatus та пилку голонасінних Callialasporitesdampieri, Araucariacites australis, Vitreisporites pallidus. Поява більшої кількості родів плавунів, вужачкових та ін. Foveosporites,Klukisporites, Lycopodiacidites та Uvaesporites, а також папоротеподібних Clathropteris obovata var. magna та домінуванняConcavisporites вирізняє батські відклади. Формування світи припадає на максимум середньо-пізньоюрської трансгресії з нормально морськими умовами накопичення осаду, продовжуються диференційовані тектонічні рухи локальних структур

Phylogeny of Palicoureeae (Rubiaceae) based on 353 low-copy nuclear genes – with particular focus on Hymenocoleus Robbr.

Members of the tribe Palicoureeae of the coffee family (Rubiaceae) have a complex taxonomic history and have been the focus of few modern systematic studies. The tribe comprises about 1,100 tropical species in ten genera. To investigate phylogeny, we used a target capture approach and the angiosperm-wide Angiosperms353 bait set to produce genomic data for a representative taxon sample of Palicoureeae, with particular focus on the African genus Hymenocoleus. Using coalescent-based inference methods, we find that Puffia gerrardii (recently separated from Geophila) is sister to Hymenocoleus. The deepest split in Hymenocoleus is highly affected by incomplete lineage sorting, possibly as a consequence of rapid speciation during the early evolution of the clade. Remaining interspecific relationships in Hymenocoleus could be confidently resolved and while Robbrecht’s traditional infrageneric classification scheme based on floral features is not supported as reflecting evolution in the group, we find that several other features do, e.g. characters of pyrenes and involucral cups. Although not free of challenges, a strong advantage with our analytical approach is that gene tree heterogeneity can be taken into account. Including flanking regions yielded data sets that had the strongest power to reject polytomies and produced less gene tree error, resulting in species trees with higher normalised quartet scores and higher average support compared to trees inferred only from exon data. Presumably paralogous loci are often filtered out prior to species tree estimation but we find that they may contribute important phylogenetic information when using an inference method that actively accounts for them

Ny bestämningsnyckel till stekelfamiljer med en reviderad klassificering inom Chalcidoidea

In December 2024, a digital identification key and associated taxon descriptions for Swedish Hymenopteran families was published in the web application Artfakta (https://artfakta.se/ taxa/3000186/artnycklar). The key is based on the Hymenoptera part of the book “Insekter – en fälthandbok” by Douwes, Hall, Hansson and Sandhall (2004, second edition), but it has been updated and adapted to the current family division. Thus, it includes several small hymenopterans that have relatively recently been defined as new families or reported from Sweden for the first time, e.g. within Chalcidoidea (Pteromalidae s.lat. and Chrysolampidae), Trigonalyoidea (Trigonalyidae) and Cynipoidea (Diplolepididae). The new families within Chalcidoidea can be reached via the family key, but there is also a separate identification key to these families available in Artfakta and in this article.

Origin and evolution of the Variscan Léon eclogites: insights from zircon and garnet petrochronology

Eclogites record the deep burial and exhumation of crustal terranes, which are key tectonic markers in the evolution of orogenic belts. Unraveling the evolution of eclogites and eclogite-bearing terranes may nevertheless be challenging, especially in old and poly-tectonic orogens such as the Variscan orogen, where these are scarce and potentially reworked. The eclogite-bearing Léon Domain (Armorican Massif, France) is one such occurrence. The Léon Domain is situated at the crossing of several (micro)continents and has long been recognized as a potential recorder for the assembly of this part of the Variscan orogen. The origin and metamorphic history of these eclogites remains nevertheless largely unconstrained. In this study, samples of the Léon eclogite were subjected to garnet and zircon petrochronology. In situ U-Pb ages from zircon cores constrain the protolith age at 385.7±2.9 Ma (concordia age, mean square weighted deviate (MSWD) = 8.7 and corresponding weighted mean age at 385.7±1.6 Ma, MSWD = 1.14), which is similar to zircon U-Pb ages reported from enclosing orthogneisses. Low δ18O values (median at 4.32 ‰) from these cores indicate interaction with surface fluids during magmatic crystallization. Garnet growth in the eclogites, as constrained by Lu-Hf geochronology, occurred at 346.5±0.8 Ma (MSWD = 0.6; Fe-Ti-rich eclogite) and 349.1±1.6 Ma (MSWD = 0.3; kyanite-bearing eclogite). Pseudosection modeling, Zr-in-rutile thermometry, and major- and trace-element maps in garnet were used to constrain the garnet growth history close to the metamorphic peak from 740 °C at 2.15 GPa to 760 °C at 2.5 GPa. Zircon separates from a cross-cutting felsic intrusion provided 321.6±2.7 Ma (MSWD = 0.76), which is taken to constrain the age of deformation and migmatization during exhumation. The new results are inconsistent with the presence of a major suture in the Léon Domain; they instead indicate that the eclogite derives from a small and short-lived back-arc basin, in which large bodies of felsic magma (enclosing orthogneiss) and smaller basaltic intrusions (the eclogite protolith) were emplaced and allowed to interact with meteoric water. The Léon Domain records rapid, cyclic inversion of this basin and thus may serve as an ancient analogue to the evolution of the Central Neotethys system, where short-lived alternating pulses of crustal extension and compression correlate with episodes of trench retreat and advance. The new tectonic interpretation for the Léon Domain supports a strong control of the slab dynamics within the frame of the protracted subduction history of the Rheic paleo-ocean

Early gigantic lamniform marks the onset of mega-body size in modern shark evolution

Lamniform sharks are amongst the largest-bodied extant fishes and have an evolutionary history spanning ~135 million years (Ma). Fossils correlate their initial development of mega-body size ( ≥6m)with ecological radiation as marine top-predators during the later part of the mid-Cretaceous (after the late Albian, ~100 Ma). Here, we push back this earliest appearance of gigantic lamniforms by ~15 Ma (upper Aptian, ~115 Ma) with the discovery of enormous cardabiodontid shark remains from northern Australia. We compiled a comprehensive dataset of vertebral centrum diameters versus maximum body length measurements for living lamniforms to calculate length and mass estimates of extinct taxa using both intraspecific and interspecific regression models. Our results show that mega-body size is an ancient lamniform trait, with the Australian cardabiodontid being around 6–8 m and over 3 tons. This rivalled some of the largest coeval marine reptiles and suggests that lamniforms invaded top-predator niches from an early stage in their adaptive evolution