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The small, primitive 'oreonetine' oreodonts from the late Eocene (Chadronian) of North America have long been a systematic mess with gross oversplitting, failure to recognise post-mortem distortion of specimens and many errors in their descriptions. We describe some new fossils and review the group for the first time since 1956. Of the six genera and nine species recognised by Schultz & Falkenbach (1956), only three genera (Oreonetes, Limnenetes, and Bathygenys) and six species are now considered valid. The 'Oreonetinae' is a paraphyletic wastebasket group because some members are closer to more derived oreodonts than others, and Limnenetes is a primitive leptauchenine, not a merycoidodontine. These small, rare late Eocene oreodonts found only in Wyoming, Montana, and Texas are the precursors to the enormous radiation of oreodonts in the early Oligocene. [ABSTRACT FROM AUTHOR]

Histological structure of long bones from bony-toothed birds (Odontopterygiformes) from Early Lutetian locality Ikove (Ukraine) is examined for the first time. Six limb bones from Pelagornithidae cf. Dasornis sp. and Lutetodontopteryx tethyensis are described. The bones, although usually being fragmented, show good preservation at the microscopic level. Their microstructure (e.g. orientation and diameter of primary osteons) significantly varies, but the basic pattern and, therefore, the way of growth matches that of recent Neognathae (as well as a number of extinct taxa). In young birds, the periosteum quickly deposited well-vascularised primary bone, which at the same time was resorbed from inside, then the animal reached adult size and fast bone growth gave way to much slower deposition of circumferential layers of lamellar or parallel-fibred tissue on the outer and inner bone surfaces. The bones also underwent Haversian remodelling of various extent (from nearly absent to nearly full), generally stronger in larger bones and in the inner compacta. Bone microstructure is consistent with high metabolic rates, expected in Odontopterygiformes, and implies that their growth rates were comparable to those of recent Neognathae. [ABSTRACT FROM AUTHOR]

Palaeogene South American faunas include enigmatic ungulates that cannot be classified unequivocally within any of the main South American (SA) Native Ungulates clades (Litopterna, Notoungulata, Astrapotheria, Pyrotheria and Xenungulata) because they retain plesiomorphic features, resembling Laurasian ‘archaic ungulates’ traditionally classified within the order ‘Condylarthra’. Most SA ‘condylarths’ are known by partial dental series and isolated teeth and unassociated postcranial remains, hampering comparisons with better-known ungulates. Here, we describe a nearly complete skull and associated mandible of an SA ‘condylarth’, Talquinodus puertai gen. et sp. nov., preserving most of the dentition and basicranium, derived from middle Eocene rocks of the Sarmiento Formation at Central Patagonia. Talquinodus shows a combination of plesiomorphic traits (complete dentition with bunolophodont cheek teeth, ring like ectotympanic, retention of stapedial system, etc.), combined with some autapomorphies, as the reduction of the m3 talonid. Our phylogenetic analyses support consistently that Talquinodus belongs to the SA radiation of Euungulata along with Litopterna, Notoungulata and Astrapotheria. However, the internal relationships could not be resolved unambiguously: Talquinodus could be a didolodontid related to the origin of Litopterna, or could be part of a separate radiation of South American archaic ungulates, along Depaulacoutoia, Lamegoia and Escribania, with no descendants in post-Eocene faunas. [ABSTRACT FROM AUTHOR]

Examples of the small beetle family Cerylonidae are scarcely represented in the fossil record or at least are rarely determined as such by specialists. Until now, only one species of an extinct genus has been reliably identified to this family from Eocene Baltic amber. A new species, Mychocerus gedanensis McHugh et Ślipiński, sp. nov. (Coleoptera, Cerylonidae), is described from Eocene Baltic amber using X-ray micro-computed tomography (μCT) and optical microscopy. This is the first extinct species described for the subfamily Ceryloninae. It belongs to the extant genus Mychocerus Erichson, 1845, the largest cerylonid genus, which has a widespread distribution that until now excluded the continental parts of the Palaearctic. The new fossil species can be placed in the North American discretus group with two remarkably similar species (M. discretus (Casey, 1890) and M. striatus Sen Gupta & Crowson, 1973) based on the presence of a long and parallel-sided prosternal process. LSID: urn:lsid:zoobank.org:act:95EA100C-3323-472C-A17B-B75480B3FB18 [ABSTRACT FROM AUTHOR]

We report here new craniodental remains from the late Eocene Krabi coal mine in Thailand that can be attributed to the suoid Siamochoerus banmarkensis Ducrocq, Chaimanee, Suteethorn & Jaeger, 1998. This material that includes the complete lower dentition and isolated upper molars provides new information on the dental morphology of this species and makes S. banmarkensis, together with Egatochoerus jaegeri Ducrocq, 1994 from Krabi, the second best documented early suoid in the Eocene of Asia. A few dental features that can be observed on these new remains suggest that S. banmarkensis might be more closely related to Suidae Gray, 1821, but it also illustrates the difficulty to attribute a precise taxonomic position to Eocene taxa. [ABSTRACT FROM AUTHOR]

Two leafy liverwort species from the late Eocene Rovno amber are described. They are placed in the extant genus Nipponolejeunea (Jubulaceae, Porellales, Marchantiophyta) that includes two extant East Asian species and one fossil species described from the Eocene Baltic amber. New fossil species N. rovnoi sp. nov. and N. solodovnikovii sp. nov. differ from the Baltic N. europea, thus making the extinct diversity of the genus exceeding the contemporary species diversity, and such a case is registered for the first time for liverworts. The finding of Nipponolejeunea in Rovno amber may indicate the presence of Abies in the Eocene of Ukraine, since at the southern border of its distribution in Japan extant species the genus grows only on fir trunk. This is in a good concordance with the recent finding in Rovno amber the longhorn beetle Poliaenus europaeus, also associated with fir trees. [ABSTRACT FROM AUTHOR]

A new species of narrow-waisted bark beetle is described from Eocene Rovno amber (Ukraine): Diagrypnodes villumi sp. nov. (Coleoptera: Salpingidae). This fossil refutes a simplistic view of the genus Diagrypnodes as a typical Gondwanan lineage whose extant species are disjunct between Australia, New Caledonia, and New Zealand. Diagrypnodes villumi is the first definitive fossil species of the subfamily Inopeplinae, the other being Eopeplus stetzenkoi Kirejtshuk and Nel from lowermost Eocene (53 Ma) Oise amber which was placed in this subfamily, albeit tentatively. Extant inopeplines occur in tropical and subtropical areas worldwide. The presence of Diagrypnodes and Eopeplus in Eocene Europe suggest a formerly different and presumably wider distribution of the subfamily. Furthermore, the ant Lasius schiefferdeckeri Mayr (Hymenoptera: Formicidae) preserved in the amber piece as a eusyninclusion with D. villumi is a new example of the simultaneous presence of the temperate and frost intolerant elements in European Eocene amber forests.LSID [ABSTRACT FROM AUTHOR]

The Eocene was a typical greenhouse climate period in the history of the Earth, with a high global sea level and extensive carbonate deposits developed in Tethys. During the Eocene, a carbonate platform was deposited in the western Tarim Basin, which belongs to the easternmost Tethys. However, the details of this carbonate platform and its complications for paleoecology and paleoclimate are still unclear. This research focuses on the bivalve-bearing carbonates of the Kalataer Formation in the western Tarim Basin, and detailed analyses of microfacies, biostratigraphy, paleoecology, and sea-level change were carried out. The bivalves of the Kalataer Formation are dominated by the Ostrea (Turkostrea) strictiplicata, Ostrea (Turkostrea) cizancourti, Ostrea (Turkostrea) strictiplicata, Ostrea (Turkostrea) strictiplicata, and Sokolowia buhsii, and the age is middle Lutetian of the Eocene. The biota of the Kalataer Formation mainly lives in open shallow sea environments, with medium to low energy and rich nutrients and oxygen, representing a typical shallow marine ecosystem of the carbonate platform. Microfacies and paleoecology indicate a large marine transgression event occurred in the western Tarim Basin during the middle Eocene. [ABSTRACT FROM AUTHOR]

The quantitative estimation of key parameters of paleotemperature and paleoprecipitation is crucial for paleoclimate reconstruction. Geochemical data from modern sediments are highly consistent with climate data, and their relationship can provide an important reference for the quantitative reconstruction of the paleoclimate. In this study, detailed inorganic geochemical analysis was carried out using high-precision sampling of the Paleogene (LFD-1 well) Guchengzi, Jijuntun and Xiloutian Formations in the Fushun Basin located in the mid-latitudes of the Northern Hemisphere. The Eocene Guchengzi Formation (54.51–47.8 Ma) and Jijuntun Formation (47.8–41.2 Ma) in the Fushun Basin were found to have been deposited under a humid climate. The lower (41.2–40.1 Ma) and upper (40.1–37.8 Ma) parts of the Xiloutian Formation were characterized by semiarid and semihumid–semiarid climates, respectively, which is very similar to the paleoclimatic information reflected by organic carbon isotopes. The Eocene Thermal Maximum 2 (ETM2, ~ 53.7 Ma), Early Eocene Climatic Optimum (EECO, ~ 53.1–46.5 Ma, Eocene Thermal Maximum 3 (ETM 3, ~ 52.8 Ma), and Middle Eocene Climatic Optimum (MECO, ~ 40.7–40.1 Ma) events significantly enhanced chemical weathering during these periods. The rapid increase in pCO2 concentration leads to an increase in temperature, precipitation, and surface runoff, exhibiting strong chemical weathering. The mean annual temperature (MATa) and mean annual precipitation (MAPa, MAPb, and MAPc) were estimated using parameters, such as the corrosion index without potassium (CIA-K), CaO/Al2O3, and (Na2O + K2O)/Al2O3. Comparing MAPa, MAPb, and MAPc with the MAP estimated using pollen data, MAPa and MAPb were found to be more sensitive to the climate during high precipitation periods (precipitation > 1000 mm, Guchengzi Formation), and the recovered average precipitation was similar to MAP. In contrast, MAPc was more sensitive to the climate during low precipitation periods (precipitation < 1000 mm, Jijuntun, and Xiloutian Formations), with higher accuracy. To fully consider the influence of soluble inorganic salts Ca2+ and Na+, multivariate linear equations of CIA-K and CaO/Al2O3 with CIA, and CIA-K and CaO/Al2O3 with MAP were constructed, namely MAPd and MAPe. The results show that MAPe has the highest performance and can be effectively used to estimate the change of paleoprecipitation in Northeast Asia. [ABSTRACT FROM AUTHOR]

Aim: The biogeographic history of most fungi is still poorly known, as well as the patterns and processes responsible for their diversification. Recent studies uncovered that most fungi have originated and present higher diversification rates in the temperate zone. The distributional pattern known for fungi is also different from many plants, animals and microbes. Using the most comprehensive phylogeny of the saprotrophic genus Coprinopsis, we aim to infer the biogeographic history and test evolutionary hypotheses in the genus. Location: Worldwide. Taxon: Fungi, Basidiomycota, Psathyrellaceae, Coprinopsis. Methods: We used a four‐gene alignment with 100 species to estimate divergence times using two fossil calibrations within Agaricales. The chronograms were used to estimate diversification rates and geographic state‐dependent models were applied. We further reconstructed the ancestral range history of the genus. Results: Molecular dating estimated that the genus has diverged ca. 41 Ma (Eocene) and was originated in the Palaearctic region. Diversification rates showed a decreasing pattern towards the present across Coprinopsis, especially after the Miocene (ca. 14 Ma). The diversification models dependent on distribution showed cosmopolitan lineages with a higher net‐diversification rates. When we compared temperate and tropical regions, we found that temperate lineages have higher net‐diversification rates. The biogeographic history of Coprinopsis estimated different routes of dispersal. The most common dispersal route was from Palaearctic to the Nearctic (15 times), followed by Palaearctic to the Neotropics (14 times). Main Conclusions: The study is the first to estimate the diversification rates and the historical biogeography of the coprinoid genus Coprinopsis. The diversification dynamics estimates in Coprinopsis are in agreement with the 'generalized diversification rates model', where we found higher diversification rates in temperate regions compared with tropical regions. In general, the ancestral area and major dispersals routes recovered in the genus are similar to findings in other groups of fungi. [ABSTRACT FROM AUTHOR]

It is debated whether there was strong climate seasonality during the Eocene, which provides a close geological analogy for near‐future scenarios of greenhouse gas emissions. Lithological data suggest the existence of a broad arid zone centered around 30°N paleo‐latitude, while a humid climate was supported by palaeobotanic assemblages in East Asia. Here, we report the occurrence of massive primary lacustrine dolomite and magnesite in the central East Asia during the middle Eocene. We provide a novel perspective from magnesium isotopes to link the formation of Mg‐carbonates to seasonal dry‐wet cycles. Rapid magnesium input during the rainy season and intense evaporation in the dry season likely caused the formation of magnesium carbonates in an enclosed lake. These findings provide insights into hydroclimatic seasonality during the Eocene, contributing to our understanding of the hydrological cycle response to a greenhouse climate. Plain Language Summary: The Eocene epoch serves as a valuable analog for future climates. While geochemical reconstructions and model simulations have illuminated lower thermal latitudinal gradients and seasonal variations, our understanding of Eocene precipitation patterns lags, encompassing wet‐dry conditions and seasonal dynamics. To enhance our understanding of Eocene precipitation patterns, we investigated a 158‐m‐thick primary dolomite and magnesite deposition in the middle Eocene lacustrine succession of the Lushi Basin, central China. From a novel perspective, we provide evidence from magnesium isotopes to link the formation of Mg‐carbonates to climate seasonality. Clumped isotopes (∆47) and Mg isotopes provide evidence supporting the formation under specific hydroclimatic conditions. A surge in magnesium input during the rainy season, succeeded by intense evaporation in the dry season, likely led to the development of extensive Mg carbonate layers in an enclosed lake. The prevalence of seasonal variations in precipitation in the central East Asia during the middle Eocene is further substantiated by a compilation of the occurrence of Eocene lacustrine Mg‐carbonates in this region. Our findings suggest that while Eocene temperature seasonal variability was weak, significant precipitation seasonality could have coexisted. Key Points: Magnesium isotopes of Eocene lacustrine dolomites and magnesites provide insight into the presence of seasonal precipitation variationMg‐carbonate formation was linked to hydroclimatic seasonality characterized by alternation between heavy rainfall and strong evaporationWeak temperature seasonal variation and significant precipitation seasonality could have coexisted in central East Asia during the Eocene [ABSTRACT FROM AUTHOR]

Deep-water benthic foraminifera are investigated from Paleocene to Eocene sediments recovered from IODP Hole U1511B in the northeastern Tasman Sea. The recovered foraminifera display exceptional three-dimensional preservation: they are relatively unaltered by sediment diagenesis and compaction.We examined 33 samples from Cores U1511B-33R to -42R, and recovered 79 species of deep-water agglutinated foraminifera (DWAF) and 13 species of calcareous benthic foraminifera. The assemblage consists entirely of "cosmopolitan" forms originally described from the Carpathians, Caucasus, Trinidad, and the western Tethys, and other DSDP/ODP sites, implying that there is little or no endemism among deep-water benthic faunas in the semi-isolated Tasman Sea. The Paleocene--Eocene interval is characterized by successive acmes of Spiroplectammina, Trochammina, ammodiscids, and Karrerulina, and therefore bears striking similarity to previously studied sections in the western Tethys and Boreal North Atlantic. The taxonomic turnover among the DWAF is minor across the P/E contact, with only three apparent extinctions and three originations from the uppermost cores of the Paleocene and the lowermost cores of the Eocene. Calcareous benthic foraminifera were not observed in the Eocene samples, possibly a result of the shoaling of the CCD. [ABSTRACT FROM AUTHOR]

The Paleogene system of the Zhuyi Depression exhibits a pronounced mechanical compaction background. Despite this compaction, remarkable secondary porosity is observed in deep clastic rocks due to dissolution processes, with well-developed hydrocarbon reservoirs persisting in deeper strata. We conducted a comprehensive study utilising various analytical techniques to gain insights into the dissolution and transformation mechanisms of deep clastic rock reservoirs in the steep slope zone of the Lufeng Sag. The study encompassed the collection and analysis of the rock thin sections, XRD whole-rock mineralogy, and petrophysical properties from seven wells drilled into the Eocene. Our findings reveal that the nature of the parent rock, tuffaceous content, dominant sedimentary facies, and the thickness of individual sand bodies are crucial factors that influence the development of high-quality reservoirs under intense compaction conditions. Moreover, the sustained modification and efficient expulsion of organic–inorganic acidic fluids play a main role in forming secondary dissolution porosity zones within the En-4 Member of the LF X transition zone. Notably, it has been established that the front edge of the fan delta, the front of the thin layer, and the near margin of the thick layer of the braided river delta represent favorable zones for developing deep sweet-spot reservoirs. Furthermore, we have identified the LF X and LF Y areas as favourable exploration zones and established an Eocene petroleum-accumulation model. These insights will significantly aid in predicting high-quality dissolution reservoirs and facilitate deep oil and gas exploration efforts in the steep slope zone of the Zhuyi Depression. [ABSTRACT FROM AUTHOR]

We report a newly discovered hydrocarbon seep deposit from the Eocene bathyal flysch, exposed in the town of Buje in Istria, Croatia. Molecular fossils of methane‐oxidizing prokaryotes and abundant banded botryoidal cements indicate strong fluid flux at this site. We systematically describe the fauna of this and another seep deposit previously reported from Buje. The faunal assemblages are composed of eight species, these being an unidentified solemyid protobranch bivalve, the nuculid Nucula bowerbanki?, the nuculanid Nuculana? sp., the mytilid Brachidontes? amanoi sp. nov., the two thyasirids Channelaxinus dinaricus sp. nov. and Thyasira histriaensis sp. nov., the lucinid bivalve Amanocina bujensis sp. nov., and a possible provannid gastropod. The two assemblages are of low diversity (4 and 5 species, respectively), and are dominated by chemosymbiotic species whose occurrence is largely restricted to seeps. Despite their spatial and stratigraphic proximity, the two deposits share only a single species, Channelaxinus dinaricus, probably due to different fluid flux regimes at both seeps. The Buje seep assemblages are among the very few Late Cretaceous to Palaeogene chemosynthesis‐based faunal assemblages from the Tethys Ocean (the others being Late Cretaceous vent assemblages from Cyprus). From an evolutionary perspective, the Buje seep communities consist of genera with Mesozoic origins but lack Cenozoic novelties such as bathymodiolin mussels and vesicomyid clams, which are known from coeval deposits from the Pacific and dominate vents and seeps today. Thus, the Buje seep fauna support previous assertions that the Eocene Tethyan seep faunas preserved an ancient aspect, whereas evolutionary novelties arose in the Pacific. [ABSTRACT FROM AUTHOR]

A new elasmobranch assemblage including 14 shark taxa, mainly lamniformes (9 taxa), is described from the Lower Eocene (NP 10–11) Kalinino Formation of the Alai River Basin, Baltai District, Saratov Region of Russia. The Nikulinka elasmobranch assemblage may have characterised inner neritic environments of the eastern part of the sub-boreal European paleobiogeographic region, being closely related to assemblages from the south-most sector of the boreal Western Siberian Province (southern Trans-Urals and Turgay straight). The absence of myliobatids in Nikulinka and Trans-Uralian localities may have been caused by the influence of Arctic water masses through meridional straits in early Ypresian. This is the first chondrichthyan assemblage from the Palaeogene of the Middle Volga Region, European Russia. [ABSTRACT FROM AUTHOR]

Rakhi Nala (Gorge) section of Eastern Sulaiman Range, Pakistan hosts world-class geological sections from the Cretaceous to the Recent. Here, Late Eocene Kirthar Formation is having a conformable lower contact with the greenish grey massive shale of the Baska Member of the Ghazij Formation. The rusty beds of the Oligocene Chitarwatta Formation are overlying the Kirthar Formation. To understand the detailed microfacies and depositional setting, detailed fieldwork was carried out in the Kirthar Formation in the outer Sulaiman Foldbelt. The late Eocene Kirthar Formation includes Habib Rahi Limestone, Domanda Shale, Pirkoh Limestone, and Drazinda Shale. Domanda Shale Member was deposited in transgression before Habib Rahi Limestone Member was deposited. It was followed up by the deposition of the second member Pirkoh Limestone and Marl Member. Habib Rahi Limestone, Pirkoh Limestone, and Marl Member have catch-up-to-keep-up deposition with rise and fall of sea level. Some facies of Drazinda and Domanda Shales represent a restricted setting supported by the presence of gypsum, while deep sea facies were also identified. This study will provide a guide for evaluating sedimentological concepts and understanding complex facies in highly oil and gas-prone stratigraphic sequences especially in the Eastern Tethys Region. [ABSTRACT FROM AUTHOR]

A rich larger foraminifera assemblage from the Eocene carbonates of the south Sabzevar region (Now-Deh section) in central Iran indicates a late Ypresian to early Lutetian age. Nine species of Alveolina d’Orbigny are studied for systematics and biostratigraphy. The assemblage includes A. minuta, A. decastroi, A. cremae, A. cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata, A. frumentiformis. We have also found nummulitids (genus Nummulites and Assilina) and orthophragmines identified as N. campesinus, N. praediscorbinus, A. placentula, A. praespira, A. reicheli, A. ex. intrec. laxispira-maior and Discocyclina archiaci bartholomei. The recovery of Alveolina cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata and Assilina praespira has permitted for the first time to extend their geographical distribution outside of the classical peri-Mediterranean area to the central Tethys regions. The obtained biostratigraphy points to the Shallow Benthic Zones SBZ11 to SBZ13, indicating the occurrence of a Lower-–Middle Eocene carbonate system. Part of the age model is supported by the calcareous nannofossil biostratigraphy that belong to the NP14b and CNE8 biozones, recorded from the central portion of the studied section. Issues regarding the application of the SBZ into the Middle East domains are discussed in terms of relative stratigraphic position and biogeographic dispersal of some significant Alveolina species. [ABSTRACT FROM AUTHOR]

A new fossil species of the leafy liverwort family Lophocoleaceae is described based on an inclusion in the late Eocene Rovno amber. Based on morphological similarity this species is assigned to the extant genus Leptoscyphus, as L. davidii sp. nov., representing the first fossil member of this genus and family. It is also the first bryophyte plant from the fossil resins being described in the Zhitomir Region. [ABSTRACT FROM AUTHOR]

Sequence stratigraphy study in mudstone and oil shale strata is difficulty but critical for the analysis of the quality unconventional oil and gas reservoirs. This contribution investigates the sequence stratigraphy of the Eocene thick organic-rich fine-grained sediments in the Fushun basin, according to the organic geochemical data measured in laboratory and predicted by the amplitude difference the resistivity and the density curve when they are overlapping (which was called ΔlogR). The sampling interval of ΔlogR was 0.125 m. The results show that the total organic carbon, the oil yield, and the petroleum potential of the Eocene mudstones prove a good linear correlation between values measured in lab and values predicted by the ΔlogR model. A total of 21 parasequences are identified in mudstones and can be divided into two cycles, a fully developed lower cycle and an underdeveloped upper cycle. There are four organic matter accumulation stages in a fully developed cycle, including two stages in the uprising half-cycle characterized by low values and rising values of the predicted geochemical data, respectively, followed by two stages in the declining half cycle characterized by high values and decreasing values of the predicted geochemical data, respectively. This contribution provides a basis for a further analysis of the characteristics of organic matter cycles in the oil shale strata of the Fushun Basin and areas with similar situation. [ABSTRACT FROM AUTHOR]

The Vacan fauna was defined by the fossil mammalian content of the Vacan Member (Sarmiento Formation) at Cañadón Vaca fossil locality (Chubut Province, Argentina), although several other local faunas from nearby areas (e.g. Río Chico oeste) were also attributed to the Vacan age estimated ca. 45–42 Ma time interval. This fauna contains poorly understood native South American ungulates, such as the Henricosborniidae. This group includes Henricosbornia, Peripantostylops, Othnielmarshia, Simpsonotus, Orome, and Nanolophodon, but both its definition and phylogenetic relationships remain unclear. In particular, Othnielmarshia and Peripantostylops were established as guide taxa of the Vacan fauna, but their knowledge has remained obscure since more than 50 years. The re-study of the Ameghino's collection and the specimens collected by the Scarritt Pocket Expeditions in Cañadón Vaca and other nearby localities allows us to 1) provide an update on the systematic status of Othnielmarshia and Peripantostylops; 2) emend their diagnoses; 3) establish comparisons with other related taxa from the same period, proposing synonymies; and 4) recognise both taxa in several local faunas from the Sarmiento and Las Flores formations. We also highlight the variability in certain controversial characters of henricosborniids, which should be evaluated for the definition of the group. [ABSTRACT FROM AUTHOR]

Late Eocene artiodactyl and creodont tracks have been reported from the Jianchuan Basin, southeastern Tibetan Plateau, representing the first and the oldest reported mammal tracks in Yunnan Province, China. Sedimentary facies analysis indicates that tracks from the upper Baoxiangsi Formation and the lower Shuanghe Formation occurred in lake shore and flood plain environments, respectively. Based on the morphological analysis, the artiodactyl tracks from the Baoxiangsi Formation are attributed to Anoplotheriipus zeuctus. Combined with fossil records and morphological characteristics, the artiodactyl and creodont tracks were probably produced by entelodonts and mesonychids, respectively. The superimposition of artiodactyl tracks with varying sizes indicates coexistence of juveniles and adults as well as their gregarious behaviour. The co-occurrence of artiodactyl tracks and creodont tracks suggests the predator–prey relationship and ecological chain during the late Eocene. The presence of mammal tracks in the Jianchuan Basin coincides with the climate change from dry to wet in the late Eocene, implying the climatic and ecological effects of the uplift of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Eloeophila is a genus of Limoniidae (subfamily Limnophilinae) with 85 extant valid species. So far, only one fossil species has been described: Eloeophila moba Podenas, from Baltic amber (Eocene). Here we have described other species from Baltic amber: Eloeophila eocenica sp. n. We also found that Cladura maculata, an Eocene species described by Scudder in 1894, from Florissant, Colorado, USA, actually belongs to Eloeophila. This species was renamed Eloeophila scudderi nom. nov. With these changes, Eloeophila now has three fossil species. [ABSTRACT FROM AUTHOR]

The Conrad Rise (CR), located midway between Antarctica and the Southwest Indian Ridge (SWIR), remains one of the least explored submarine large igneous provinces (LIPs) in the Indian Ocean to date. Relying on only seafloor paleomagnetic records, early studies hypothesized that the formation of the CR occurred during the Late Cretaceous. Here, we present new geochemical and geochronological data, including Sr‒Nd‒Pb‒Hf isotopes and 40Ar/39Ar data. Our results indicate that the uppermost part of the CR (Ob and Lena seamounts) unexpectedly formed later than previously predicted, at approximately 40 Ma in an intraplate setting. Another small seamount north of the Ob seamount formed later, at 8.5 Ma. The isotopic composition of lava from the small seamount north of the Ob seamount overlaps with that commonly defined by the Indian plume component. Overall, the isotopic variations defined by the volcanic suite from the CR could be accounted for by a three‐component mixing model involving the common component, lower continental crust, and depleted mantle endmembers. The newly obtained 40Ar/39Ar ages imply that the CR volcanism might have been triggered by major regional plate reorganizations during the middle to late Eocene and the late Miocene, inducing the release of a small upwelling rising from the African large low‐velocity province. Plain Language Summary: The Conrad Rise is a large oceanic volcanic plateau in the Indian Ocean. Previous studies have provided only vague estimates of when it formed because very few direct studies of the area have been performed, and no geochronological studies have been conducted. This study presents new geochemical data for the Conrad Rise, including isotopes and radiometric ages. The results suggest that the uppermost part of the Conrad Rise formed approximately 40 million years ago and that the small seamount in the northern part of the Conrad Rise formed 8.5 million years ago in an intraplate setting. The Sr‒Nd‒Pb‒Hf isotopic signature of lavas from the Conrad Rise might be derived from a ternary mixture between the common mantle component present in other lavas from the Indian Ocean, lower continental crust remnants, and the depleted mantle. The new age data indicate that the late volcanic activity might have been triggered by the release of a small plume from the African superplume caused by regional plate reorganization. Key Points: This is the first report of geochronological lava data from the Conrad Rise, an aseismic ridge in the southwestern Indian OceanContrary to previous hypotheses, late volcanism at the Conrad Rise occurred in the middle to late Eocene and the late MioceneThe isotopic features of the Conrad Rise result from a mixture of common Indian Ocean plume components and lower continental crust [ABSTRACT FROM AUTHOR]

After successfully diversifying during the Paleocene, the descendants of the first wave of mammals that survived the end‐Cretaceous mass extinction waned throughout the Eocene. Competition with modern crown clades and intense climate fluctuations may have been part of the factors leading to the extinction of these archaic groups. Why these taxa went extinct has rarely been studied from the perspective of the nervous system. Here, we describe the first virtual endocasts for the archaic order Tillodontia. Three species from the middle Eocene of North America were analyzed: Trogosus hillsii, Trogosus grangeri, and Trogosus castoridens. We made morphological comparisons with the plaster endocast of another tillodont, Tillodon fodiens, as well as groups potentially related to Tillodontia: Pantodonta, Arctocyonidae, and Cimolesta. Trogosus shows very little inter‐specific variation with the only potential difference being related to the fusion of the optic canal and sphenorbital fissure. Many ancestral features are displayed by Trogosus, including an exposed midbrain, small neocortex, orbitotemporal canal ventral to rhinal fissure, and a broad circular fissure. Potential characteristics that could unite Tillodontia with Pantodonta, and Arctocyonidae are the posterior position of cranial nerve V3 exit in relation to the cerebrum and the low degree of development of the subarcuate fossa. The presence of large olfactory bulbs and a relatively small neocortex are consistent with a terrestrial lifestyle. A relatively small neocortex may have put Trogosus at risk when competing with artiodactyls for potentially similar resources and avoiding predation from archaic carnivorans, both of which are known to have had larger relative brain and neocortex sizes in the Eocene. These factors may have possibly exacerbated the extinction of Tillodontia, which showed highly specialized morphologies despite the increase in climate fluctuations throughout the Eocene, before disappearing during the middle Eocene. [ABSTRACT FROM AUTHOR]

Changes in fire ecology during warm and cold periods in the geological past are important because of their effects on terrestrial ecosystems and the global carbon cycle. We examined the charcoal concentrations of the Erden Obo section in Inner Mongolia to reconstruct the evolution of wildfire and their relationship to the regional vegetation from the Late Paleocene through Early Oligocene. Our data show that fire frequency were relatively high from the end of the Paleocene to the beginning of the Eocene, in accord with other paleofire records worldwide. However, low fire frequency occurred during the Early Eocene Climate Optimum (EECO), coincident with the change in the regional vegetation from shrubland to forest due to the strengthening of the regional rainfall, and we suggest that the humid climate may have been responsible for this decrease. High frequency fire occurred after the Middle Eocene, near-synchronously with the transition ofthe regional vegetation from forest to steppe. The high-frequency fire was most likely triggered by regional drought during the aridification process after the Middle Eocene. We propose that these temporal changes in the fire ecology were consistent within the northern temperate zone from the Late Paleocene through Early Oligocene, and we suggest that studies of global wildfires need to be evaluated within the context of paleovegetation zones and ecosystem evolution. [ABSTRACT FROM AUTHOR]

The Eocene (56–34 million years ago) is characterized by declining sea surface temperatures (SSTs) in the low latitudes (∼4°C) and high southern latitudes (∼8–11°C), in accord with decreasing CO2 estimates. However, in the mid‐to‐high northern latitudes there is no evidence for surface water cooling, suggesting thermal decoupling between northern and southern hemispheres and additional non‐CO2 controls. To explore this further, we present a multi‐proxy (Mg/Ca, δ18O, TEX86) SST record from Bass River in the western North Atlantic. Our compiled multi‐proxy SST record confirms a net decline in SSTs (∼4°C) between the early Eocene Climatic Optimum (53.3–49.1 Ma) and mid‐Eocene (∼44–41 Ma), supporting declining atmospheric CO2 as the primary mechanism of Eocene cooling. However, from the mid‐Eocene onwards, east‐west North Atlantic temperature gradients exhibit different trends, which we attribute to incursion of warmer waters into the eastern North Atlantic and inception of Northern Component Water across the early‐middle Eocene transition. Plain Language Summary: Over the past 541 million years, the Earth has oscillated between warm (greenhouse) and cold (icehouse) climates. The most recent transition between a greenhouse and icehouse climate state occurred during the Eocene (56–34 million years ago). This transition shows a gradual cooling, previously suggested to be driven by a decline in atmospheric carbon dioxide (CO2). However, we know little about this transition in the North Atlantic Ocean. Previous studies show limited cooling of surface waters in this region. This suggests that changes in North Atlantic temperatures are not driven by CO2. To understand how sea surface temperature changes in the western North Atlantic, we analyzed the chemistry of microscopic marine fossils in sediments. Our results show a 4°C decline in temperature from the early (∼53 Ma) to the middle Eocene (∼42 Ma). This matches computer simulations of Eocene climate and confirms CO2 was responsible for the transition. The lack of cooling observed in previous work is probably due to the development of an ancient water mass known as Northern Component Water (observed today as North Atlantic Deep Water) and changes in how the Eocene ocean transported heat. Key Points: Long‐term (∼4°C) decline in North Atlantic sea surface temperatures (SSTs) between the early (∼53–49 Ma) and middle (∼44–41 Ma) EoceneThis indicates that CO2 was likely responsible for the onset of long‐term Eocene coolingHowever, east‐west temperature gradients in the North Atlantic are decoupled, possibly due to additional non‐CO2 forcing mechanisms [ABSTRACT FROM AUTHOR]

From the Eocene (∼50 million years ago) to today, Southern Ocean circulation has evolved from the existence of two ocean gyres to the dominance of the Antarctic Circumpolar Current (ACC). It has generally been thought that the opening of Southern Ocean gateways in the late Eocene, in addition to the alignment of westerly winds with these gateways or the presence of the Antarctic ice sheet, was a sufficient requirement for the transition to an ACC of similar strength to its modern equivalent. Nevertheless, models representing these changes produce a much weaker ACC. Here we show, using an eddying ocean model, that the missing ingredient in the transition to a modern ACC is deep convection around the Antarctic continent. This deep convection is caused by cold temperatures and high salinities due to sea‐ice production around the Antarctic continent, leading to both the formation of Antarctic Bottom Water and a modern‐strength ACC. Plain Language Summary: The evolution of ocean circulation from the early Southern Ocean around 50 million years ago to today has seen much debate over the past decades. The main characteristic of the modern Southern Ocean is the prevalence of the Antarctic Circumpolar Current (ACC), the world's strongest current. In the past it has been thought that the deepening of ocean gateways, and changes in the strength and location of winds, led to an ACC of similar strength to its modern equivalent. Nevertheless, ocean models simulating these changes typically reproduce an ACC with less than a third of the modern ACC's strength. Here we show that the missing ingredient in the transition to a modern ACC is deep convection around the Antarctic continent. Deep convection is due to a combination of cooling and increase in salinity by sea ice formation which allows for water at the ocean surface to become denser than the water below, leading to the mixing of the water column to great depths. This deep convection allows for the ocean to be energized, leading to a modern‐strength Antarctic Circumpolar Current. A cool climate around the Antarctic continent is therefore crucial for the development of a modern‐strength Antarctic Circumpolar Current. Key Points: Deep convection is able to drive a strong Antarctic Circumpolar Current (ACC)Surface cooling and sea ice formation are crucial drivers of this deep convectionACC similar to a rim current around convective sites, energizing ocean circulation [ABSTRACT FROM AUTHOR]

The Eocene (56–34 million years ago) is characterized by declining sea surface temperatures (SSTs) in the low latitudes (∼4°C) and high southern latitudes (∼8–11°C), in accord with decreasing CO2 estimates. However, in the mid‐to‐high northern latitudes there is no evidence for surface water cooling, suggesting thermal decoupling between northern and southern hemispheres and additional non‐CO2 controls. To explore this further, we present a multi‐proxy (Mg/Ca, δ18O, TEX86) SST record from Bass River in the western North Atlantic. Our compiled multi‐proxy SST record confirms a net decline in SSTs (∼4°C) between the early Eocene Climatic Optimum (53.3–49.1 Ma) and mid‐Eocene (∼44–41 Ma), supporting declining atmospheric CO2 as the primary mechanism of Eocene cooling. However, from the mid‐Eocene onwards, east‐west North Atlantic temperature gradients exhibit different trends, which we attribute to incursion of warmer waters into the eastern North Atlantic and inception of Northern Component Water across the early‐middle Eocene transition. Plain Language Summary: Over the past 541 million years, the Earth has oscillated between warm (greenhouse) and cold (icehouse) climates. The most recent transition between a greenhouse and icehouse climate state occurred during the Eocene (56–34 million years ago). This transition shows a gradual cooling, previously suggested to be driven by a decline in atmospheric carbon dioxide (CO2). However, we know little about this transition in the North Atlantic Ocean. Previous studies show limited cooling of surface waters in this region. This suggests that changes in North Atlantic temperatures are not driven by CO2. To understand how sea surface temperature changes in the western North Atlantic, we analyzed the chemistry of microscopic marine fossils in sediments. Our results show a 4°C decline in temperature from the early (∼53 Ma) to the middle Eocene (∼42 Ma). This matches computer simulations of Eocene climate and confirms CO2 was responsible for the transition. The lack of cooling observed in previous work is probably due to the development of an ancient water mass known as Northern Component Water (observed today as North Atlantic Deep Water) and changes in how the Eocene ocean transported heat. Key Points: Long‐term (∼4°C) decline in North Atlantic sea surface temperatures (SSTs) between the early (∼53–49 Ma) and middle (∼44–41 Ma) EoceneThis indicates that CO2 was likely responsible for the onset of long‐term Eocene coolingHowever, east‐west temperature gradients in the North Atlantic are decoupled, possibly due to additional non‐CO2 forcing mechanisms [ABSTRACT FROM AUTHOR]

Simple Summary: The tests of the unicellular protozoan Nummulites distans (Cenozoic era, Paleogene period) were studied using X-ray diffraction. In addition, the images obtained using X-ray microtomography and scanning electron microscopy were analyzed. A high degree of the calcite crystal orientation ordering that the test consists of has been revealed. It is higher than that of calcite from the shells of the bivalve mollusk Placuna placenta, whose shell is formed by a special multicellular tissue. So, it is found that already unicellular organisms have strict control over the crystal arrangement. Unicellular protozoa form calcium carbonate tests. It is important to understand the features and mechanisms of its formation. This may shed light on the processes of shell formation in metazoans. One of the most important characteristics of the Protozoa carbonate test is the degree of crystal ordering that can be described by crystallographic texture. The crystallographic texture data of calcite in the foraminifera Nummulites distans (Deshayes) test from the Eocene deposits (Cenozoic, Paleogene) of the Crimea Peninsula are obtained using X-ray diffraction. A very strict orientation of the crystals is revealed. The calcite texture sharpness is several times greater than in the shells of the bivalve mollusk Placuna placenta (Linnaeus), measured by the same method. It also exceeds the crystallographic texture and sharpness of the same mineral in the shells of the bivalves of Mytilus galloprovincialis (Lamarck), studied by neutron diffraction. It is concluded that a high level of control during test formation is already characteristic of protozoa. Studying the processes involved in the formation of a very sharp crystallographic texture can become an important direction for creating nature-like materials with desired properties. [ABSTRACT FROM AUTHOR]

The beetle family Ptilodactylidae is recorded for the first time from Rovno amber, Ukraine. Ptilodactyla odnosum Telnov, Perkovsky, Kundrata and Bukejs sp. nov. and a male of P. eocenica Kundrata, Bukejs and Blank, 2021 are described and illustrated using X-ray micro-computed tomography. Our discoveries of two species in Rovno amber together with recently published findings in Baltic amber and Bembridge Marls suggest that ptilodactylids were rather diverse in Eocene Europe. Identification key to Ptilodactylidae described from European Eocene ambers is provided, and relationships of the Baltic and Rovno amber coleopterofaunas are briefly discussed. [ABSTRACT FROM AUTHOR]

We present new disarticulated cranial elements of the Eocene frog Thaumastosaurus from several localities in the Phosphorites du Quercy, France, providing novel information about the variation of its anatomical characteristics. With the use of micro-computed tomography (μCT) scanning technology, we examine and discuss various types of dermal cranial ornamentation in extant Pyxicephalus , the closest extant relative of Thaumastosaurus , in which these features are useful in species diagnoses, paying particular attention to the individual and ontogenetic variation, and sexual dimorphism, as well as interspecific variation among extant species. We suggest that various types of dermal cranial ornamentation in Thaumastosaurus could be potentially used in diagnoses at species level, although ontogenetic variation should be taken into consideration. Apart from ornamentation, the size and general morphology of the maxillae and squamosa in Thaumastosaurus reveal an unexpected disparity of morphotypes, which suggests the potential presence of cryptic taxa. Some squamosa reveal that their processus zygomaticus extended up to the postnasal wall, so their associated maxillae were excluded from the orbital margin, whereas others were short and their respective maxillae participated in the formation of the orbital margin. Thaumastosaurus is envisaged as the product of an Early Palaeogene direct, potentially overseas, dispersal from isolated Afro-Arabia to Europe. [ABSTRACT FROM AUTHOR]

During the Paleogene, the Holarctic experienced drastic climatic oscillations, including periods of extensive glaciation. These changes had a severe impact on both the flora and fauna causing widespread extinction and range shifts with some taxa retreating to refugia in the Mediterranean Basin. Here we provide evidence for this hypothesis using fossils from the pseudoscorpion family Garypinidae Daday, 1889 (Arachnida: Pseudoscorpiones). This family comprises 21 extant genera from all continents except Antarctica but is restricted to low mid-latitudes (<44°N) in the Northern Hemisphere. We provide the second record of garypinids from the European succinite ambers of the Eocene by describing the first extinct genus in Garypinidae, Baltamblyolpium gen. nov., which includes two species: Baltamblyolpium gizmotum sp. nov. from Baltic amber and Baltamblyolpium grabenhorsti sp. nov. from Bitterfeld amber. The new genus exhibits a morphology that closely resembles Neoamblyolpium Hoff, 1956 from western North America and the genus Amblyolpium Simon, 1898, which is widespread but includes taxa restricted to Mediterranean refugia in Europe. The discovery of a new fossil genus of Garypinidae from Europe confirms that the family was found at more northerly latitudes during the Eocene, however, extinction and range contraction resulted in their present-day relictual distribution in southern Europe like many other lineages that once thrived in the European "Baltic amber forest" of the Eocene. [ABSTRACT FROM AUTHOR]

Astrochronologically calibrated deep‐sea records document the Cenozoic (66–0 Ma) global climatic cooling in great detail, but the magnitude of sea‐level fluctuations of the middle Eocene Warmhouse state (47.8–37.7 Ma) and the ∼40.3 Ma warming event of the Middle Eocene Climatic Optimum (MECO) is not well constrained. Here, we present a sequence stratigraphic classification of a shallow marine mixed carbonate—clastic ramp system for this time interval in Paris basin, France. Based on sedimentologic, paleogeographic and biostratigraphic data, we hypothesize that the 22 elementary sequences recognized each correspond to the long cycle of orbital eccentricity (0.405 Myr). With the exception of the MECO, the shoreline trajectory of superimposed, third‐order depositional sequences evolved in phase with the very long cycles of orbital eccentricity (2.4 Myr), suggesting significant polar ice build‐up leading to sea level lowstands during nodes of the very long eccentricity cycle. Inferred from Fischer Plot methodology, Lutetian third‐order eustasy was in the order of 5–10 m and during the MECO 30 m or more. Furthermore, the shallow‐water record implies that third order sea‐level changes were astronomically paced in the middle Eocene Warmhouse climate state, but a decoupling occurred during the transient MECO warming. Key Points: Astronomical calibration of shallow water carbonatesEocene sea‐level changes paced by very long eccentricityInsolation driven sea‐level changes (third order) were 5–10 m [ABSTRACT FROM AUTHOR]

Extant species of Liquidambar L. exhibit a disjunct distribution between western and eastern Asia and eastern North America to Central America, with the highest species diversity being in China. In this study, two new species of Liquidambar are described from the Eocene of Hainan Island, South China: L. hainanensis on basis of the leaf fossils, and L. ovoidea based on compressions of infructescences. The co‐occurrences of L. hainanensis leaves, associated infructescences of L. ovoidea and dispersed pantoporate pollen grains have the combination of morphological features peculiar to the genera Liquidambar and former Semiliquidambar and Altingia. This is considered further palaeobotanical justification for the placement of these three genera into a single genus, Liquidambar, proposed earlier based on molecular markers. Our data provide evidence for the occurrence of an ancestral polymorphic group of Liquidambar species (L. maomingensis with associated capitate infructescences, L. bella, L. hainanensis and L. ovoidea) during the Eocene in South China, and corroborate the view that South China could have been a centre of Liquidambar speciation during the Eocene. The morphological similarity of L. hainanensis leaves to those of the extant species L. orientalis from Western Asia and the North American L. styraciflua may support the importance of both the North Atlantic Land Bridge and the Bering Land Bridge for the dispersal of Liquidambar. Analysis of fossil species of Liquidambar from eastern Asia also contributes to further understanding of patterns in the taxonomic diversity and evolutionary history of this genus. [ABSTRACT FROM AUTHOR]

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Within the Himalayan collisional belt, granites occur along two subparallel belts, namely, the Tethyan Himalayan Sequence (THS) and the Greater Himalayan Crystalline Complex (GHC). In this study, Eocene adakitic rocks and leucogranite are found only in the northern Himalayas, so further research is required to constrain their origin. Here, we present zircon U–Pb and monazite U–Th–Pb ages, Sr–Nd–Pb and Hf isotopes, and whole-rock major and trace elements for Liemai muscovite granite in the eastern Himalayan region. The U–(Th)–Pb results show that Liemai muscovite granite was emplaced at 43 Ma, and that its geochemical characteristics are similar to those of adakitic rocks of the same age (Dala, Quedang, Ridang, etc.). Combined with previous studies, both Eocene adakitic rocks and leucogranite are high-potassium calc-alkaline peraluminous granites. The former is relatively rich in large-ion lithophile elements (LILEs), such as Ba and Sr, and relatively deficient in high-field-strength elements (HFSEs), such as Nb, Ta, Zr, and Y, with weak or no Eu anomalies, and the average light rare earth element (LREE)/heavy rare earth element (HREE) ratio is 17.8. The latter is enriched in LILEs (such as Rb) and U, Ta, and Pb, and depleted in HFSEs (such as Nb and Zr), La, and Nd, with obvious negative Sr, Ba, and Eu anomalies and a mean LREE/HREE ratio of 10.7. The 87Sr/86Sr of the former is in the range of 0.707517–0.725100, εNd (t) ranged from −1.2 to −14.7, the average is −11.6, εHf (t) ranged from −0.5 to −65, the average is −12.2. The average values of (206Pb/204Pb) i, (207Pb/204Pb) i and (208Pb/204Pb) i are 18.788, 15.712 and 39.221, respectively; The 87Sr/86Sr of the latter is in the range of 0.711049~0.720429, εNd (t) ranged from −9.8 to −13.8, the average is −12.3, εHf (t) ranged from −4.2 to −10, the average is −6.7. The isotopic characteristics indicate that adakitic rocks and leucogranites are derived from the ancient lower crust, and both may be derived from metamorphic rocks of the GHC. In this paper, the origin of the two is associated with the transformation of the Himalayan tectonic system during the Eocene, and it is inferred that the deep crust may have altered the tectonic environment (temperature and pressure), resulting in an obvious episodic growth trend of leucogranite and significant development of adakitic rocks from 51 to 40 Ma. From 40 to 35 Ma, the development of Eocene magmatic rocks was hindered, and adakitic rocks disappeared. It is proposed that the genetic difference is related to the transition from high to low angles of the subducting plate in the crustal thickening process. [ABSTRACT FROM AUTHOR]

The 2023 discovery of a fish fossil from lower Eocene strata of the Chuckanut Formation provides new insights into the paleoenvironment and paleoecology of one of the region's most prolific fossil deposits. The detrital clastic fluvial and floodplain deposits of the Chuckanut Formation are not favorable for the preservation of fish, but the high quality of preservation of this specimen is evidence that some Chuckanut Formation sediments provide suitable depositional conditions for the preservation of skeletal remains. This information improves our understanding of the range of depositional environments within the Chuckanut Formation, and provides clues for searching for additional specimens. The discovery of this fossil has larger significance; the skeletal remains of fish are scarce in fluvial and floodplain deposits. Despite its incompleteness, dorsal fin and caudal fin ray anatomy suggest that the specimens represent the extinct genus Phareodus, an open-water carnivore that has previously only been reported in North America from the Green River and Bridger Formations in Wyoming and Utah, USA. [ABSTRACT FROM AUTHOR]

The Middle Eocene microfauna of the Fore-Magura Unit contains rich foraminiferal assemblages with numerous trochospiral, agglutinated species originally described as Trochammina subvesicularis Hanzlíková. The paper provides a reconsideration of this taxon due to its inconclusive generic status. A new insight into the systematics of trochamminid species is also discussed. A total of 25 samples from Middle Eocene slope marl deposits of the Fore-Magura Unit (from the western part of the Polish Outer Carpathians) were taken for examination. Based on the analysis of 183 specimens recovered from deep-sea mixed foraminiferal assemblages the species is assigned to the genus Ammogloborotalia (Zheng & Fu). The Eocene specimens, named under different generic names and in open nomenclature, similar to the description of Trochammina subvesicularis Hanzlíková, should be referred to the taxonomic name Ammogloborotalia aff. subvesicularis. Similar to modern species of Ammogloborotalia (Zheng & Fu), their Middle Eocene representatives imply a bathyal water depth and good connection of the flysch-type Fore-Magura zone basin with the World Ocean. [ABSTRACT FROM AUTHOR]

Two new species of the genus Demimaea from the subfamily Curculioninae are described from Rovno amber. Demimaea zherichini n. sp. is similar to the extant Demimaea mori but differs by its black antennae and tarsi, larger body, body lacking dense, white setae, sparsely not coarsely punctate pronotum and its narrower elytral interstriae. Demimaea gratshevi n. sp. differs from D. zherichini n. sp. by its smaller body, its comparatively longer scape extending towards the compound eye and its convex and wide elytral interstriae. This is the first fossil record of the subtribe Demimaeina. Assumptions are made about the presence of Moraceae plant species in the Eocene of Northern and Eastern Europe, particularly the genus Ficus. LSID urn:lsid:zoobank.org:pub:D89E9989-37B6-4E71-9D6E-8D616DAD2C75 [ABSTRACT FROM AUTHOR]

The first cerambycid from Eocene Rovno amber, Poliaenus europaeus n. sp. (Lamiinae, Pogonocherini) is described. The new species is the first known fossil of Poliaenus Bates, 1880, as well as the first representative of this genus in Europe. Relations with extant species and with the putative hosts of this fossil are discussed, leading to suppose the presence of Abies in Eocene of Ukraine. urn:lsid:zoobank.org:pub:0E67C646-09FE-4789-94A5-313EAB48B797 [ABSTRACT FROM AUTHOR]

The members of the family Lepidopsocidae (Psocodea: Trogiomorpha) are commonly known as scaly-winged barklice based on the presence of scales on body and wings. Interestingly, the members of the subfamily Thylacellinae, which is the sister group to the remaining members of the family, lack scales and are characterised by densely setose body and wings. We describe the thylacelline Parathylacella oisensis gen. et sp. nov. from the Eocene amber of Oise (France), corresponding to the only known fossil genus of the family. We compare it with the other genera in the subfamily. It shows a similar habitus to the genus Thylacella, and both may be closely related. The description of the new taxon increases the poorly known palaeodiversity of the lepidopsocids. We comment on the putative palaeobiology of this group and discuss new insights into the palaeobiogeography and early diversification of the subfamily Thylacellinae. An association between the thylacelline barklice and Detarieae (Fabaceae: Caesalpinioideae) trees is plausible. The biogeographic distribution might be partially explained by this association, combined with oceanic currents. Studies on Cretaceous lepidopsocids, as well as other Cenozoic specimens, are crucial to understand the evolution of this group over time, and the possible vicariance process. [ABSTRACT FROM AUTHOR]

Vast and geochemically diverse volcanic rocks from the western Alborz Magmatic Assemblage (AMA) represent the back-arc of the central Iran Neotethyan arc (Urumieh–Dokhtar Magmatic Assemblage; UDMA). Volcanic rocks of the west AMA record valuable information on the timing, source region(s) and geodynamic setting of magmatism. Over 30 days of field study and sampling, investigation of 170 thin sections, 30 whole-rock geochemical analyses, 13 whole-rock Sr–Nd isotopic ratios and U–Pb age dating of zircon separates from 7 samples furnished the present study data. Eocene (38.5 Ma) OIB-type volcanic rocks from South Kaleybar indicate an anorogenic (extensional) setting. This lithospheric-scale extensional event induced influx of asthenospheric mantle into the sub-arc wedge, of which the partial melts differentiated to produce OIB-type melts. The OIB-type melts incorporated some inherited zircons in their ascent through the Cadomian crust. A continued extensional regime led to asthenospheric upwelling and produced mafic melts that produced 27.5-Ma-old subalkaline series volcanics. The LILE-depleted signature of the South Kaleybar subalkaline volcanic rocks implies that their mantle source region experienced previous partial melting event(s), probably during OIB-type magmatism in the Eocene. Alkaline volcanism (24.4 Ma) and concurrent high-silica adakitic volcanism (24.3 Ma–23.4 Ma) followed subalkaline magmatism. The alkaline rock signature in the study area range from 'Nb–Ta depleted' to 'plume-type'. This is consistent with lithosphere–asthenosphere interaction in an arc-related setting. Simultaneous partial melts of delaminated lower crustal rocks reacted with the asthenosphere and produced adakitic melts. Asthenospheric, lithospheric and crustal contribution to the magmatism in South Kaleybar express the back-arc signature of magmatism in Eocene to Late Oligocene times. [ABSTRACT FROM AUTHOR]

Based on inclusions in Eocene Baltic amber, two new fossil species of the family Cantharidae, namely Podosilis groehni sp. nov. (the second fossil species of the genus) and Silis (Silis) carsteni sp. nov., are described and illustrated. These new species are compared with the other known taxa of both genera from various amber deposits. [ABSTRACT FROM AUTHOR]

Based on a well-preserved specimen in Eocene Baltic amber, a new species Globicornis samlandensis sp. nov. (Coleoptera: Dermestidae) is described and illustrated. The new fossil species differs from extinct congeners in having antennomere 10 short and subtriangular with a rounded apex, and about as long as wide; while the pronotum and elytra are unicolorous dark brown, and covered with unicolorous dark setae (without patches). An updated key to fossil Globicornis species known from Baltic amber is also provided. [ABSTRACT FROM AUTHOR]

We present two robust and well‐dated paleomagnetic poles from upper Eocene and Oligocene volcanics in the Urumieh‐Dokhtar magmatic arc, Central Iran. These two poles place Iran ∼3.7°–3° of latitude south of its present position between ca. 40 and 23 Ma. Our new paleomagnetic declination data indicate that the Central Iran block may have experienced a ∼11.6° clockwise rotation since the Late Eocene. We integrated our new data with the retrodeformed margins of the Zagros collision zone and contemporaneous Arabia positions to better constrain the age and configuration of the Arabia and Eurasia assembly process. In our model, the Arabia‐Eurasia collision occurred first in the western Main Zagros suture between ca. 35 and 30 Ma and then diachronously spread eastwards. Our paleogeographic reconstruction and initial continental collision timing supports the Arabia‐Eurasia collision as a first‐order driver of global cooling, Red Sea rifting, and Mediterranean extension. Plain Language Summary: The demise of the Neo‐Tethyan ocean and accompanied continent‐continent collisions created the thick crust and the low relief surfaces of the Iran Plateau and Tibetan Plateau. The onset timing and configuration in the Zagros collisional belt are critical for understanding the uplift of the Iran Plateau, tectonic evolution of the Mediterranean and Zagros regions, as well as the associated Cenozoic climate change. However, the age and configuration of the Arabia‐Eurasia continental collision are hotly debated. Previous works generated competing collision timing estimates ranging from Late Cretaceous to Pliocene, with most estimates from Eocene to Miocene. By conducting geochronology and paleomagnetism on the Eocene‐Oligocene volcanic rocks in Central Iran, we show that the Arabia‐Eurasia collision occurred first in the western Main Zagros suture at the Eocene/Oligocene boundary, and then diachronously spread eastwards. We suggest the Arabia‐Eurasia collision facilitates the slowing of Africa, the opening of the Red Sea, the extension in the Mediterranean, and the Eocene/Oligocene global cooling. Key Points: Our paleomagnetic results indicate a ∼3.7°–3° of latitude south of the present position of Central Iran during ca. 40–23 MaCentral Iran has experienced ∼11.6° clockwise rotation since ca. 40 MaArabia‐Eurasia collision began at the Eocene/Oligocene boundary in the western Main Zagros suture and diachronously spread eastwards [ABSTRACT FROM AUTHOR]

Summary: Fossil discoveries can transform our understanding of plant diversification over time and space. Recently described fossils in many plant families have pushed their known records farther back in time, pointing to alternative scenarios for their origin and spread.Here, we describe two new Eocene fossil berries of the nightshade family (Solanaceae) from the Esmeraldas Formation in Colombia and the Green River Formation in Colorado (USA). The placement of the fossils was assessed using clustering and parsimony analyses based on 10 discrete and five continuous characters, which were also scored in 291 extant taxa.The Colombian fossil grouped with members of the tomatillo subtribe, and the Coloradan fossil aligned with the chili pepper tribe. Along with two previously reported early Eocene fossils from the tomatillo genus, these findings indicate that Solanaceae were distributed at least from southern South America to northwestern North America by the early Eocene.Together with two other recently discovered Eocene berries, these fossils demonstrate that the diverse berry clade and, in turn, the entire nightshade family, is much older and was much more widespread in the past than previously thought. [ABSTRACT FROM AUTHOR]

The article presents the results of the study of continental palynomorphs from the amber-bearing Upper Eocene deposits in the Primorsky quarry (Kaliningrad oblast, southeastern coast of the Baltic Sea). Three spore and pollen assemblages were identified and calibrated with the dinoflagellate cyst Rhombodinium perforatum and Thalassiphora reticulata zones. The "Blue Earth" Member of the Prussian Formation of the early Priabonian age is characterized by the Tricolporopollenites exactus–T. retiformis–Quercoidites microhenrici assemblage. The upper Priabonian "Upper Quicksand" and "White Wall" members of the Prussian Formation and the Palvé Formation are characterized by the Platanipollis ipelensis–Castaneoideaepollis oviformis–Tricolpopollenites foraminatus assemblage. The Inaperturopollenites–Sciadopityspollenites–Sequoiapollenites assemblage was recognized in the uppermost Palvé and lowermost Kurshskaya formations of the terminal Priabonian. During the Late Eocene, the climatic conditions on the territory of the modern southern Baltic area were quite warm and humid, close to subtropical ones. Mixed coniferous-broad-leaved forests grew along the shores of the marine paleostrait, while the open spaces were occupied by heat-loving evergreen and moderately heat-loving deciduous shrubs and low-lying land areas were swamped. Gradual regression of the sea basin, which began at the end of the Priabonian, led to an increase in swampy areas on land, while the climate was still quite warm and humid. [ABSTRACT FROM AUTHOR]

Small reticulateNummulites are found across the Eocene shallow marine deposits of the Paris Basin, Belgium, as far north as northern Germany and southern United Kingdom. Only two isolated instances of Nummulites at higher latitudes than this are known, from the Rockall bank and Wyville-Thomson ridge in the north Atlantic, and no Nummulites have been reported from the Nordic North Sea Basin – until now. Here Nummulites planulatusis described within a glacial erratic dredged from Jyske Rev in the Danish North Sea of likely Ypresian age. Whilst the specimen is not in situ, it indicates that populations ofNummulites were living further north in the North Sea region than previously known. This range expansion may have been facilitated by the hyperthermal events of the early Eocene. [ABSTRACT FROM AUTHOR]

Magmatic activity in the Sakarya Zone, an important segment of the Alpine orogenic belt, continues intermittently from the middle Carboniferous to Miocene. In this study, we provide geochronological and geochemical data from the Dağdibi Pluton in the eastern Sakarya Zone to present some inferences on the source region and petrogenesis of the middle Eocene magmatism. U–Pb zircon geochronology from two granodiorite samples gives middle Eocene ages of 44.75 ± 0.92 and 45.01 ± 0.59 Ma. The pluton is mainly composed of K-feldspar, plagioclase, quartz, Mg-hornblende/actinolite, Fe–Ti oxides and small amounts of biotite, and secondary chlorite and epidote. Parental magma of the intrusive rocks has a high-K calc-alkaline affinity with metaluminous character. The oxygen fugacity values vary between −18 and −17. The rocks show slightly radiogenic 87Sr/86Sr(i) (0.704845–0.705726) ratios and ϵNdi values between −0.96 and +0.52. Pb–Pb isotope ratios are typical for those of the lower continental crust. ϵHf(i) values of the zircons range from 0.14 to 10.26. The geochemical and isotopic features of the pluton point to a parental magma derived from a depleted mantle that was metasomatized by fluids during previous subduction events. The volumetric abundances of the rock types are decreased as the silica content increase, implying that the fractional crystallization is the most important process during the formation of the present compositional range of the pluton. Amphibole, plagioclase and Fe–Ti oxides are the fractionated phases while K-feldspar is largely accumulated. In the light of the data presented above, slab breakoff is regarded as the geodynamic process responsible for the formation of the Dağdibi Pluton in the middle Eocene. [ABSTRACT FROM AUTHOR]

The Eocene-Oligocene Transition (EOT) was one of the most profound climate changes in the Cenozoic era, characterized by global cooling around 34 million years ago. This time period also witnessed major faunal turnovers, such as the "Mongolian Remodeling" of Asia, characterized by the dominance of rodents and lagomorphs after the EOT. Previous studies have primarily focused on overall faunal change across the EOT. Here, we examined one genus, the earliest ctenodactylid Karakoromys, based on rich fossils from continuous sections at Ulantatal, Nei Mongol, magnetostragraphically dated to latest Eocene-Early Oligocene. Based on a systematic paleontological study of these fossils, we recognized four species of Karakoromys (Karakoromys decussus, K. arcanus, K. chelkaris, and K. conjunctus sp. nov.), indicating a relatively high diversity of the most primitive ctenodactylids during the latest Eocene-Early Oligocene (~34.9–30.8 Ma). The turnover of ctenodactylids primarily occurred during a regional aridification event around 31 Ma rather than during the EOT cooling event, suggesting that regional precipitation variation in the semi-arid area may have played a more important role than global temperature change in the evolution of early ctenodactylids. [ABSTRACT FROM AUTHOR]