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\nHighlightsA new and intriguing fossil Mallomonas species, M. enigmata, was uncovered from 10 strata in the Eocene Giraffe Pipe locality. The new species represents an ancient member of the section Punctiferae, and based on scale and bristle morphology is most closely related to the modern congener, M. nieringii. M. nieringii is a rare species known from a suite of acidic waterbodies on the Cape Cod peninsula, Massachusetts, USA. Only a few modifications of the body scales differ between M. enigmata and M. nieringii, and the new taxon was uncovered from a section of the Giraffe Pipe maar lake representing a shallow and acidic waterbody. Cysts of M. enigmata are oval, with a small pore surrounded by a narrow hyaline zone. The anterior ~ ¼ of the cyst surrounding the hyaline zone consists of a series of small, closely spaced, rimmed holes that penetrate the wall. Otherwise, the cyst wall is smooth and unornamented. Unlike any known modern species in the genus, a second type of body scale is produced, but found only attached to the cyst. It is hypothesized that these scales may represent unfinished body scales that became fused to the cyst during its development. A new fossil Eocene species of Mallomonas.A unique second scale morphotype attached to the cyst.Thrived in a shallow, humic and acidic freshwater pond.A new fossil Eocene species of Mallomonas.A unique second scale morphotype attached to the cyst.Thrived in a shallow, humic and acidic freshwater pond. [ABSTRACT FROM AUTHOR]

We describe two exceptionally preserved fossil snakes from the Eocene Konservat-Lagerstätte of Geiseltal, located in the state of Saxony-Anhalt, Germany. The two snake specimens, GMH LIX-3-1992 and GMH XXXVIII-20-1964, can be confidently identified as booids based on general morphology and were thus compared to other geographically and/or temporally close fossil booids. We found that GMH LIX-3-1992 is morphologically very similar to Eoconstrictor spinifer , also from Geiseltal, and to Eoconstrictor fischeri , from the middle Eocene of Messel, but differs from both in a number of cranial and vertebral features. Based on these differences we erect the new species Eoconstrictor barnesi sp. nov. ; GMH XXXVIII-20-1964 is very similar to GMH LIX-3-1992 and the two differ only in features that are likely ontogenetic. Phylogenetic analyses of snakes using maximum parsimony and Bayesian inference on datasets inclusive of both morphological and molecular data consistently support a close affinity of E. barnesi to E. fischeri and E. spinifer. Our preferred phylogenetic hypothesis places the three species of Eoconstrictor in a clade that is sister to Neotropical Boidae, a result consistent with previous studies. The genus Eoconstrictor could provide an important calibration point for molecular clock studies of booids and snakes in general. [ABSTRACT FROM AUTHOR]

How gabbro affects the generation and expulsion of hydrocarbons in muddy surrounding rocks is clarified by analyzing thin section, major and trace elements, total organic carbon (TOC), pyrolysis, extracts and vitrinite reflectance data from source rocks in the Chunxi area the Dongying Sag, Bohai Bay Basin, eastern China. The results show that a magma intrusion brings copious heat to the source rocks, which promotes abnormal maturation of organic matter (OM) and rapid hydrocarbon generation. The CH4 and H2 produced by gabbro alteration play a role in hydrocarbon generation of source rocks. The hydrothermal process during magma intrusion provides many different minerals to the source rock, resulting in carbonate‐rich surrounding mudstone. The carbonate and clay minerals produced by volcanic mineral alteration jointly catalyze the hydrocarbon generation of the source rock. The high‐temperature baking of the intrusion results in hydrothermal pressurization and hydrocarbon generation pressurization, causing many fractures in the surrounding rock. The generated oil and gas are discharged through the fractures under diffusion and pressure. Mantle‐derived CO2 is also conducive to the expulsion of hydrocarbons because of its strong enrichment capacity for hydrocarbons. [ABSTRACT FROM AUTHOR]

The palynological analysis of the Paleogene and Neogene sequences of the southern part of West Siberia (borehole 2, Novosibirsk oblast) showed that the conifer bisaccate pollen in the spore–pollen spectra exhibits a series of morphological features allowing its comparison with the modern pollen of Cathaya argyrophylla Chun et Kuang. These palynomorphs belong to relict vegetation, which currently occurs in the wet subtropical climate of South China, and are important climate indicators. The palynomorphs are ascribed to the ancestral forms of the species Cathaya as Abietineaepollenites sellowiiformis (Zaklinskaja) Doweld 2018. The pollen is described, and its distribution along the section is shown. The maximum amount of the A. sellowiiformis pollen (up to 23.7%) is confined to the upper part of the Oligocene and the Lower Miocene and its last appearance is recognized in the Middle–Upper Miocene. These data expand our knowledge on the geographic range of the Cathaya ancestral form and its role in plant communities of Central Asia in the Cenozoic. [ABSTRACT FROM AUTHOR]

We report the results of organic geochemical analyses of 19 crude oil samples from reservoir sandstones in the 4th Member of the Eocene Shahejie Formation from wells in the Minfeng Sag, Dongying Depression, Bohai Bay Basin (NE China). In addition, 42 Shahejie Formation core samples of dark‐coloured mudstones, including 28 extracts, were analysed. Geochemical data included Rock‐Eval measurements, gas chromatography, GC‐MS and diamondoid analyses. Maceral analyses showed that mudstones in the 4th Member of the Shahejie Formation ("Es4") contain Types I and II1 kerogen. The member can be divided into upper (Es4s) and lower (Es4x) intervals. Oil‐prone Es4s rock samples have good to excellent hydrocarbon‐generating potential based on calculated initial TOC values; Rock‐Eval Tmax values indicate that they are sufficiently mature for hydrocarbon generation. Analytical results suggest that both Es4s and Es4x mudrocks are potential source rocks for oils produced at fields in the Minfeng Sag. Analysed crude oils from the Minfeng Sag were classified into three genetic groups. Group I oils are mature to highly mature and have undergone a moderate degree of thermal cracking. They are characterized by a low β‐carotane/nC25 ratio and C30 4‐methylsterane index (4MI); high values of oleanane index (oleanane /C30‐hopane), C27 diasterane/C27 regular sterane (C27Dia/C27), regular sterane/17α hopane and gammacerane/C30 hopane (G/H); and medium pristane/phytane ratios (Pr/Ph). This suggests that Group I oils are mostly derived from source rocks in the upper part of the Es4x unit which are interbedded with evaporites. Group II oils are mature and have high 4MI and Pr/Ph ratios, low oleanane index, regular sterane/17α hopane and C27Dia/C27 ratios, and mediumβ‐carotane/nC25 and G/H. These features are similar to those of Es4s source rocks, indicating their genetic correlation. Group III oils show the lowest maturity and highβ‐carotane/nC25 and regular sterane/17α hopane, and low oleanane index, Pr/Ph and 4MI. Previously‐published data indicates that oils similar to those in Group III were mainly sourced by Es4s mudstones. [ABSTRACT FROM AUTHOR]

The remains of a unique fossil bony fish were discovered in late Eocene (39.1–36.7 Ma: NZ Kaiatan stage) mudstone at Burnside near Dunedin, New Zealand in the 1930s and subsequently named and described by Frederick Chapman. He interpreted the type specimen as being a large-scaled relative of the modern Thyrsites of the Gempylidae (Scombroidei: Trichiuroidea), known to be swift, large oceanic predators. However, Chapman is unlikely to have seen all of the fossil, and did not discuss the skull and caudal skeleton. Additional material now allows these to be included in the expanded description herein, including key morphologic features of the fish such as the presence of premaxillary fangs. This study describes the rather complex history of the specimen and re-examines this significant fossil fish in the University of Otago collections, giving a more complete understanding of Eothyrsites morphology, paleoecology and relationships. In summary, we suspect Eothyrsites represents an ancestral form of gempylid, closely related to the gemfish group, an important Southern Hemisphere macrofossil record from the Eocene seas around Zealandia. [ABSTRACT FROM AUTHOR]

The Rose Canyon fault is the southern extension of the larger Newport-Inglewood-Rose Canyon fault system, which represents a major structural boundary in the Inner Continental Borderland (ICB) offshore of southern California. Ten to fifteen percent of total plate boundary motion in southern California is thought to be accommodated by the faults of the ICB, but the exact distribution of slip is uncertain. With an onshore segment, the Rose Canyon fault offers an opportunity to measure the slip rate using traditional geodetic methods. In this study, we use Global Positioning System (GPS) surface velocities from a combined campaign and continuous GPS network to constrain elastic models of the Rose Canyon fault. We then compare the observed surface velocities with proposed conceptual models of regional fault connections that facilitate the transfer of slip into the Rose Canyon fault to assess how well the observations are explained by the models. The results of elastic half-space models suggest that the Rose Canyon fault may be slipping toward the higher end of geologic estimates, with the preferred model indicating a slip rate of 2.4 ± 0.5 mm/yr. Although limited in terms of near-fault benchmarks, we find an improved model fit using an asymmetrical elastic half-space model and a higher slip rate, suggesting a potential rheological contrast across the Rose Canyon fault, similar to observations from the northern Newport-Inglewood fault segments. Observed GPS surface velocities, background seismicity, and gravity anomalies south of San Diego Bay point toward a more easterly trace for the Rose Canyon fault, suggesting a possible connection with the San Miguel-Vallecitos fault system. Such a connection could increase the potential rupture lengths of future earthquakes and have important consequences for regional seismic hazards. [ABSTRACT FROM AUTHOR]

Paleogene age deposits east of the Fifteenmile River, northwest of Dawson City, Yukon, Canada preserve a diverse high‐latitude fossil flora. Here, we provide new data on the age of the fossil site based on laser ablation–inductively coupled plasma–mass spectrometry (LA‐ICP‐MS) U‐Pb dating of tephra zircons, paleobotanical paleoclimate reconstructions, and growing season length estimates based on photoperiod. These new data indicate an age of the Fifteenmile River fossil locality as late middle Eocene and likely within the Middle Eocene Climatic Optimum episode. The paleoflora‐based paleoclimate reconstruction indicates the region was relatively wet and warm with non‐freezing winters, but also experienced seasonal dryness, with an approximate 7 months long growing season as suggested by photoperiod. We interpret this paleoclimate as summer dry and winter wet—a climate analogous to modern day warm Mediterranean climates in the Köppen‐Geiger climate classification system. These findings provide a new perspective on the past climate and environment of high‐latitude ecosystems during warm greenhouse intervals and contribute to our understanding of the Earth's climate history and its potential future changes. Key Points: New U‐Pb data show the Fifteenmile River fossil flora age is late middle Eocene, potentially within the Middle Eocene Climatic OptimumWest central Yukon had a warm Mediterranean climate, with wet, mild winters and a distinct summer‐dry season during the late middle EoceneGrowing season length at high latitudes during greenhouse intervals would be determined by photoperiod, not temperature [ABSTRACT FROM AUTHOR]

The article describes the first find of a bird from the Paleogene of Siberia. A fragment of tibiotarsus from the Eocene Tavda Formation of the Tyumen Region (Western Siberia) is assigned to Procellariiformes. The bird is morphologically closer to Procellariidae, but comparable in size to albatrosses (Diomedeidae) and is assumed to represent the stem members of the family. The find indicated for the first time that either stem albatrosses or similar large Procellariiformes could have had a worldwide distribution as early as the Eocene. [ABSTRACT FROM AUTHOR]

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]

In this report we describe 32 species belonging to 26 genera of Caenogastropoda from the early Eocene Cambay Shale of the Cambay Basin, western India. This is the first report of gastropod fossils from this basin, and introduces 24 new species, 2 new subgenera and 3 new genera. The new genera, Eopreangeria, Indobatillaria and Pachycerithium, include new species Eopreangeria mangrolensis, Indobatillaria ismatae and Pachycerithium richardi. The new subgenera are Lyrispina in the genus Lyria and Carinotoma in the genus Apiotoma, including new species Apiotoma (Carinotoma) rammohani. The remaining new species are: Amaurellina cambayensis, Ampullina vastanensis, Amp.? eocenica, Ptychocerithium shamukum, Bittium purnimae, Bi. kamalae, Pseudobellardia sitae, Serratocerithium indicum, Potamides mosaliensis, Pot. shahensis, Sandbergeria khanae, Benthonella prosoclinata, Teinostoma maryae, Natica naroliensis, Involuta? ishwari, Rimella rokeyae, Siphonalia kalpanae, Si. pritilatae, Strepsidura reticulata and Amalda bibhae. A palaeoenvironmental analysis and the diversity–abundance pattern of this fossil fauna provide evidence of an overall marginal marine environment that experienced the Ypresian marine transgression and a gradual increase in marine influence. [ABSTRACT FROM AUTHOR]

Source rocks characterized by shale-dolomite interbeds were widely developed in oil group Ⅱ, the lower Member of Xingouzui Formation in Jianghan Basin. A breakthrough has been made recently in shale oil exploration of shale-dolomite interbeds, while the presence of gypsum and salt deposites in saline lake on shale porosity restrains the process of shale oil exploration. Objective It is of great significance for shale oil exploration to clarify the controlling factors of the organic-rich shale lithofacies with low content of gypsum and salt. Methods Well C1 penetrated stratigraphic unit of the Xingouzui Formationin the Chentuokou Depression, Jianghan Basin was studied. Based on the core and thin section observations and the analyses of whole rock mineral compositions, organic carbon contents (TOC), and geochemical elements, a systematic study on lithofacies, sedimentary environment, and main controlling factors of organic matter accumulation were conducted. Results The classification of fine-grained sediments and the saline lacustrine sedimentary model in Jianghan Lake Basin were established. Lithofacies of oil group Ⅱ, the lower Member of Xingouzui Formation Xingouzui Formation in Well C1 can subdivided into seven types: organic-rich laminated dolomite facies, organic-rich layered dolomite facies, organic-contain massive dolomite facies, organic-rich laminated mixed shale facies, organic-rich layered mixed shale facies, organic-contain layered siltstone, and organic-poor massive gypsum-salt rock facies. The co-evolution of paleoclimate, paleosalinity, and paleoredox resulted in the diversity of lithofacies development, and the main controlling factor of organic matter accumulation was the anoxic palaeo-water body. The favorable lithofacies for shale oil exploration are organic-rich/organic-contain laminated/layered dolomite/mixed shale, which deposited in semi-deep lake with brackish water, anoxic condition. Conclusion This study reveals the controlling factors for the development of organic-rich lithofacies and its depositional environment of oil group Ⅱ, the lower Member of Xingouzui Formation in the Chentuokou Depression, which can provide valuable insights for shale oil exploration of Xingouzui Formation in related Depression in Jianghan Saline Basin.

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 Paleogene coal deposits of the Jaintia Hills of Meghalaya have undergone examinations by various researchers, primarily focusing on organic petrography and geochemistry and highlighting the rank, type, and grade, with perspectives on potential utilization. However, the genesis of these coals has received limited attention from the researchers. This research article addresses this gap by conducting a comprehensive examination of the geochemical and mineralogical aspects of these coals. Coal samples from two coal seams at nine locations in the Sampar coalfield in Jaintia Hills were collected and studied. The samples are subjected to X-ray fluorescence spectroscopy, X-ray diffraction analyses, Fourier transform infrared spectroscopy, proximate, and ultimate analysis to study geochemical and mineralogical composition and ash yield. The study utilizes various geochemical proxies based on the inorganic constituents, providing insights into the paleo-depositional conditions and contributing to a deeper understanding of the unique characteristics of Meghalayan coals. The research indicates that these coals were formed in coastal swamps and lagoons on stable platforms, experiencing minimal tectonic activity, influenced by seawater incursions. These coals were deposited in reducing to significantly reducing conditions and warm and humid to semi-arid climatic conditions. No signature of a geothermally active fluid has been recorded. [ABSTRACT FROM AUTHOR]

[Display omitted] • Middle–Late Eocene palynoflora were systematically studied in the Fushun Basin. • Intensified aridity and climatic oscillations started at 41.2 Ma. • Onset of aridification was widespread across mid-latitude Asia at 41 Ma. • Abrupt aridification at 41 Ma linked to the proto-Paratethys Sea retreat. The initial aridification of mid-latitude Asia is thought to be one of the most prominent Cenozoic environmental changes in Asia. However, precisely dated, fine-grained sediments documenting initial aridity beyond central Asia are extremely rare. Here, we reconstruct the history of Middle-Late Eocene (47.8–37.8 Ma) hydroclimate change in northeast China using continuous palynological records from a lacustrine sedimentary sequence in the Fushun Basin. Our results indicate that the onset of aridification occurred concurrently with increased climatic variability at 41.2 Ma, as expressed by a sharp increase in xerophytic Ephedra and mountainous coniferous forest at the expense of an abrupt decrease in broadleaved forest, along with frequent alternations between semi-desert and swamp forest vegetation after 41.2 Ma. The climate changed markedly from a stable, warm-wet climate during the Middle Eocene to a cooler, drier climate with pronounced warm-dry and cold-wet oscillations during the Late Eocene. This finding challenges the previously prevailing idea that the East Asian monsoon was significantly enhanced in northeast China after 41–40 Ma. A comprehensive comparison of records from eastern and central Asia demonstrates that the onset of aridification and enhanced climate variability after 41 Ma were widespread across mid-latitude Asia. This may be explained by reduced moisture transport by the westerlies and strengthening of high- and low-latitude forcing linked to the coeval retreat of the proto-Paratethys Sea. [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]

Bats appear in the fossil record on multiple continents during the early Eocene. More than seventy Eocene bat species have been named to date, including stem bats, probable members of crown families, and others of uncertain affinity. Most phylogenetic analyses of Eocene bat relationships have focused on the handful of taxa known from nearly complete skeletal material, whereas the taxonomic relationships of more incomplete fossils have been based largely on phenetic similarities. Here we evaluate the evolutionary relationships of over 60 species of Eocene bats—including many taxa known only from fragmentary craniodental remains—in an explicitly phylogenetic context. Our analysis is based on nearly 700 morphological characters scored in 82 taxa, including 20 extant species representing all living bat families other than Pteropodidae. We found that phylogenetic relationships of Eocene bats are more complex than previously thought. Numerous families (e.g., †Archaeonycteridae, †Mixopterygidae, †Palaeochiropterygidae) and genera (e.g., †Archaeonycteris, †Icaronycteris, †Carcinipteryx) were found to be non-monophyletic as previously recognized, requiring adjustments to chiropteran taxonomy. Four major clades of stem bats were recovered in our analyses. †Microchiropteryx folieae (~ 54 Ma, India) was recovered as the earliest crown bat, occurring as the most basal lineage of Vespertilionoidea, whereas many putative crown bats were recovered among stem Chiroptera. †Tachypteron franzeni was found to be a crown bat in our analyses, as in previous studies, but it was recovered unexpectedly as a stem miniopterid. The phylogenetic relationships presented here represent the most comprehensive analysis of Eocene bat relationships completed to date, substantially improving our understanding of the position of many fossil taxa within Chiroptera and providing a foundation for future analyses of bat evolution. [ABSTRACT FROM AUTHOR]

Embrithopoda is an extinct clade of herbivorous placental mammals belonging to the afrotherian subclade Paenungulata. Early in their evolutionary history, embrithopods colonized the insular terrane of Balkanatolia, presumably via dispersal across the Tethyan marine barrier that separated Africa from Eurasia during the early Cenozoic. Here we report new embrithopods from the early Eocene locality of Çamili Mezra, Çiçekdaği Basin, central Anatolia, which document the early co-occurrence of two sympatric species of embrithopods, including Crivadiatherium sevketseni sp. nov. and Crivadiatherium sahini sp. nov. The genus Crivadiatherium, otherwise known only from the late Eocene of Romania, is reported for the first time in Anatolia. Hypsamasia seni from the middle Eocene of north-central Anatolia is interpreted as a nomen dubium. Embrithopod specimens previously described as Palaeoamasia sp. nov. from the Eocene-Oligocene transition of the Boyabat Basin in northern Anatolia are identified as a new genus and species, Axainamasia sandersi. The embrithopod fauna of Çamili Mezra indicates that this clade experienced at least a modest adaptive radiation after successfully colonizing Balkanatolia. The Balkanatolian record of embrithopod evolution contrasts with the evolutionary history of this clade in its native Africa, where sympatric embrithopod taxa have never been documented. [ABSTRACT FROM AUTHOR]

Although the evolutionary history of anthropoid primates (monkeys, apes, and humans) appears relatively well‐documented, there is limited data available regarding their origins and early evolution. We review and discuss here the earliest records of anthropoid primates from Asia, Africa, and South America. New fossils provide strong support for the Asian origin of anthropoid primates. However, the earliest recorded anthropoids from Africa and South America are still subject to debate, and the early evolution and dispersal of platyrhines to South America remain unclear. Because of the rarity and incomplete nature of many stem anthropoid taxa, establishing the phylogenetic relationships among the earliest anthropoids remains challenging. Nonetheless, by examining evidence from anthropoids and other mammalian groups, we demonstrate that several dispersal events occurred between South Asia and Afro‐Arabia during the middle Eocene to the early Oligocene. It is possible that a microplate situated in the middle of the Neotethys Ocean significantly reduced the distance of overseas dispersal. [ABSTRACT FROM AUTHOR]

A new fossil bird is described from the Upper Lumbrera Formation of Northwestern Argentina. Lumbrerornis rougieri gen. et sp. nov. is represented by three-dimensionally preserved elements of the hindlimb of a single individual. Morphological comparative studies and particular characters of the tibiotarsus suggest that the new species might be related to the extinct clades Palaeotididae and Geranoididae of the Northern Hemisphere, which were recently hypothesized to be Paleogene palaeognathous birds. However, the fragmentary preservation of the new fossil prevents a confident systematic position. The Upper Lumbrera Formation is a widely recognized fossiliferous unit with a very rich fauna of mammals and other vertebrates (e.g., fishes, crocodilians, turtles, snakes). This is the first record of a three-dimensionally preserved fossil bird from the Eocene of northwestern Argentina and thus provides fresh evidence of the Eocene faunas from the area and improves our understanding of the poorly known early Paleogene avifaunas from South America.

Paleocene-Eocene aged sediments from the east of Tuz Gölü Basin (Central Türkiye) provide significant data for foraminifera contents and their paleoenvironmental clues. They are important in revealing the stratigraphy of the region and the Paleocene-Eocene geological history of Türkiye. The sediments, composed mainly of carbonates, are known as Karapınaryaylası Formation. In this formation, benthic foraminifera representing SBZ2 to SBZ12 biozones corresponding to the Selandian-Late Cuisian time interval were identified in ten measured stratigraphical sections. The zonal interval from the E7 Zone (late Ypresian) to the E10 Zone (Lutetian) is characterized by the marker species of planktonic foraminifera defined in the clayey limestones from the uppermost part. The studied formation is divided into four main facies and eleven sub-microfacies types. The clayey limestone levels of the Karapınaryaylası Formation, which generally starts with a transgressive sequence, contain abundant planktonic foraminifers, while the lithologies of grainstone, packstone and wackestone are rich in benthic foraminifers. Benthic foraminifer assemblages indicate different paleoenvironments from lagoon to back-bank, bank and fore-bank. The obtained foraminiferal data show the Selandian-Lutetian age range and various paleoenvironments from the lagoon to the open sea.

Past responses to environmental change provide vital baseline data for estimating the potential resilience of extant taxa to future change. Here, we investigate the latitudinal range contraction that terrestrial and freshwater turtles (Testudinata) experienced from the Late Cretaceous to the Paleogene (100.5-23.03 mya) in response to major climatic changes. We apply ecological niche modeling (ENM) to reconstruct turtle niches, using ancient and modern distribution data, paleogeographic reconstructions, and the HadCM3L climate model to quantify their range shifts in the Cretaceous and late Eocene. We then use the insights provided by these models to infer their probable ecological responses to future climate scenarios at different representative concentration pathways (RCPs 4.5 and 8.5 for 2100), which project globally increased temperatures and spreading arid biomes at lower to mid-latitudes. We show that turtle ranges are predicted to expand poleward in the Northern Hemisphere, with decreased habitat suitability at lower latitudes, inverting a trend of latitudinal range contraction that has been prevalent since the Eocene. Trionychids and freshwater turtles can more easily track their niches than Testudinidae and other terrestrial groups. However, habitat destruction and fragmentation at higher latitudes will probably reduce the capability of turtles and tortoises to cope with future climate changes.

The Paleogene cypraeoidean fauna of the northeast Pacific region (NEP), extending from Vancouver Island, British Columbia, Canada southward to Baja California Sur, México, consists of 12 genera, 20 named species (three of which are new), six open-nomenclature species, one Cypraeidae, indeterminate to genus and species, one cf. species, and four nomina dubia. All taxa are figured here. Species reassigned at the genus level are Protocypraea? simiensis (Nelson, 1925) and Luponovula maniobraensis (Squires and Advocate, 1986). Improved documentation of known NEP species include Propustularia kemperae (Nelson, 1925), Grovesia castacensis (Stewart, 1926) [1927]), G. mathewsonii (Gabb, 1864), and Eratotrivia crescentensis (Weaver and Palmer, 1922). The three new species, Subepona leahae, Bernaya kaylinae, and Eocypraea judithsmithae are from the upper lower Eocene Llajas Formation of Simi Valley, Ventura County and Devil Canyon, Los Angeles County, California. Six open-nomenclature species need better preserved material; they are: Bernaya sp., two Protocypraea? sp., Gisortia sp., Eocypraea sp., and Cypraedia sp., as does an indeterminate cypraeid from the Lodo Formation of central California. Nomina dubia are “Bernaya” fresnoensis (Anderson, 1905), “Eocypraea” bayerquei (Gabb, 1864), “Sphaerocypraea” martini (Dickerson, 1914), and “Sulcocypraea” oakvillensis (Van Winkle, 1918). Eratotrivia mackini (Durham, 1944) is herein reassigned to the synonymy of Grovesia mathewsonii (Gabb, 1869). The NEP Paleocene cypraeoidean fauna consists of four genera, a cypraeid of unknown generic affinity, and two nomina dubia. The early Eocene “Capay Stage” cypraeoidean fauna is comprised of eight genera and two nomina dubia. That was during the peak of NEP cypraeoidean biodiversity, which coincided with the “Early Eocene Climate Optimum” (EECO), the warmest time of the Paleogene. At the end of “Capay” time, biodiversity abruptly decreased, and this trend continued to the end of “Domengine Stage” time, when a faunal turnover took place. The cypraeoidean faunas in the subsequent “Tejon Stage” and Galvinian Stage continued to be diminished because of the ongoing cooling of the ocean waters. Continued global cooling eventually caused the disappearance of the thermophilic Paleogene NEP cypraeoideans before the beginning of the Oligocene. Most of the NEP cypraeoidean fauna is very similar morphologically to species found in the Tethys region of Europe, especially France, Italy, and Ukraine. These similar species are indicative that the introduction of most of the NEP cyraeoidean genera into the NEP region was via a westward-directed, warm-water current originating in the ancient Tethys Sea region of western Europe. The point of origin of the Paleocene Propustularia is unknown, and the late Eocene Nuceolaria most likely arrived in the NEP region via a Pacific Ocean route.

Systematic documentation of pteriomorph bivalves of the late Eocene–early Oligocene Keasey Formation in western Oregon follows previous monographic treatments of the anomalodesmatans and heteroconchs. It includes material from coeval Cascadia Margin strata in southwestern Washington in the context of major molluscan faunal turnover during the dramatic doubthouse climate transition from an ice-free tropical marine environment to the establishment of permanent polar ice caps and a cold temperate marine climate. The families represented are Crenellidae, Parallelodontidae, Glycymerididae, Limopsidae, Isognomonidae, Pectinidae, Propeamussiidae, and Limidae. New taxa include the genus Bathyisognomon and five new species: Limopsis squiresi, Bathyisognomon smithwickensis, Delectopecten kieli, Delectopecten keaseyorum, and Propeamussium (Parvamussium) mistensis. Small to minute mud pectens and glass scallops are among the most abundant and frequent taxa in the Keasey fauna, although they are poorly preserved and have been overlooked heretofore. Pteriomorphs are prominent elements of recurring associations of species in mudstone and fine-grained siltstone facies adjacent to three Keasey cold methane seeps. Previously described Keasey anomalodesmatans and heteroconchs in these seep-adjacent strata have living relatives adapted to dysoxia and toxic geochemistry. Because the unique macrofaunal associations in these settings are neither seep fauna nor part of the background fauna, this paper introduces and defines the concept of a transitional peri-seep biotope. Relationships, monophyly, systematic resolution within major pteriomorph groups, and global biogeographic distributions are reviewed in each systematic treatment. Recurring patterns include occurrences in active margin settings, inferred oscillatory deepening of the calcium carbonate compensation depth, late Eocene origin of two-layered oceans following establishment of the Antarctic Circumpolar Current, and biogeographic gateway changes that disrupted earlier Paleogene larval dispersal patterns.

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]

A new species of soldier beetle (Cantharidae) from Eocene Baltic amber, Malthodes maierae sp. nov., is described and illustrated from a male specimen discovered in Russia. The new species differs from the hundreds of known extant and extinct species of Malthodes Kiesenwetter, 1852. The last abdominal segments, which are substantially modified on the male to hold the female during mating, differ considerably in Malthodes species and are very important diagnostic elements for this genus. The exact evolutionary forces driving these manifold modifications are unknown, but they are likely related to sexual selection, mate recognition, antagonistic coevolution, or varying habitats, or a combination of two or more of these factors.The Zoobank LSID for this is: urn:lsid:zoobank.org:pub:DC13FC31-BD71-4C3D-9536-B70AF65FB699 [ABSTRACT FROM AUTHOR]

In this first report on the re-investigation of the Eocene Messel palynoflora using combined light- and scanning electron microscopy, comprising Algae to Vitales, it is shown that this epic paleoflora can still provide new insights into the ancient ecosystem prevailing at that time. Applying this combined single-grain method on the palynomorphs enabled us to identify several new floral elements represented in the palynoflora, as well as to revise previous spore/pollen classifications, resulting in a higher taxonomic resolution of the microflora. So far, we have discovered three different algae remains, 28 spore types, and pollen from seven different gymnosperms and 26 unique angiosperms. Some of the new taxa include Lycopodiaceae, Cycadales, Stratiotes (Hydrocharitaceae), and Poaceae. The spore/pollen flora was compared to the meso/macroflora, revealing the importance of combining meso/macrofossil records with state-of-the-art microfossil analyses for a more holistic representation of the paleoflora. This is reflected in the number of taxa only occurring in the microflora (ten families) versus that of the meso/macroflora (18 families). Comparing the results from this qualitative combined light- and scanning electron microscopy study to classical quantitative light microscopy methods already suggests that the combined method provides a higher diversity of spore/pollen taxa. Still, potential floral newcomers could be missed in such single sample investigations that are otherwise detected in the classic up-trough section analyses. [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]

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]

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]

The presence of an Eocene subduction event, in addition to Jurassic and Cretaceous ones, in the Rhodopes of Greece and Bulgaria is controversial. We report the first dating of an eclogite from the Lower Allochthon of the Rhodopes. The eclogite is a mafic lens enclosed in orthogneiss of the Arda‐2 Unit at Chepelare, Central Rhodopes. It was metamorphosed under conditions of ca. 25 kbar, 700–750°C. Garnet grains have outward‐increasing Mg contents and omphacite inclusions with the highest jadeite contents in their rims, indicating garnet growth under increasing pressure. Lu–Hf geochronology yielded an age of 48.7 ± 1.5 Ma. The age is linked to a late stage of garnet growth close to peak pressure, i.e. to subduction. [ABSTRACT FROM AUTHOR]

The study area lies in the south of Mamoniyeh, a part of the Zaviyeh 1:100000 geological map, which covers the middle part of the Urumieh-Dokhtar magmatic arc. The volcanic phases and the intrusive masses constitute the predominant rocks of the area which has been subjected to magmatic and tectonic activities. Thus, owing to the lack of detailed studies on the volcanic rocks of this area, we try to link the tectonic setting and the magmatic evolution of the rocks under study. In addition, magma evolution processes, such as fractional crystallization, crustal contamination, and magma mixing may play an important role in the genesis of these rocks. The present paper presents new petrological and geochemical data on these volcanic rocks, which were formed during the Eocene. The Urumieh Dokhtar Magmatic arc is characterized by a series of volcanic and plutonic rocks that formed during the Late Cretaceous to Early Miocene, approximately 95 to 20 million years ago, and extends for about 2,000 kilometers. [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]

Simple Summary: The majority of dipterans (flies, mosquitoes, and their allies) spend most of their lifetimes as immatures (larvae and pupae). Yet, immature dipterans are seldom reported in the fossil record. Studying this life stage can provide crucial insights into the evolution of these insects, how distinct evolutionary lineages relate to each other, and their ecological interactions during the significant changes of the Mesozoic Era (about 252–66 Ma). In this work, based on a range of imaging techniques, we describe and discuss several fossil dipteran larvae from amber and compression fossils, exhibiting forms not known in the modern fauna. These specimens possess structures similar to those found in present day larvae of awl-flies and water snipe-flies. Additionally, we report new specimens of stratiomyomorphan larvae, which appear to have dominated over other terrestrial dipteran immatures, suggesting a potentially larger ecological role in the past than in present times. Finally, we describe two additional specimens of a highly distinctive dipteran, known only as a larva, Qiyia jurassica Chen et al., 2014. Our findings suggest differences in the ecology of some fly groups compared to their modern relatives. They also challenge some postulated evolutionary relationships within these lineages. Diptera are one of the four megadiverse groups of holometabolan insects. Flies perform numerous ecological functions, especially in their larval stages. We can assume that this was already the case in the past; however, fly larvae remain rare in most deposits. Here we report new dipteran larvae preserved in Cretaceous (about 99 Ma) Kachin amber from Myanmar and, even older, Jurassic (about 165 Ma) compression fossils from China. Through light microscopy and micro-CT scanning we explore their peculiar morphology and discuss their possible phylogenetic affinities. Several larvae seem to represent the lineage of Stratiomyomorpha. A few others present characters unique to Xylophagidae (awl-flies), as well as to Athericidae (water sniper-flies), resulting in a chimeric morphology. Understanding the exact relationships of most of these specimens with a particular lineage remains challenging, since they differ considerably from any other known dipteran larvae and present some unique traits. Additionally, we report new specimens of Qiyia jurassica Chen et al., 2014, supposedly parasitic larvae, most likely representatives of Athericidae. These new findings offer valuable insights into the evolution of the early diversification of the brachyceran flies and underscore the importance of immature stages in understanding the evolutionary history and ecology of flies. [ABSTRACT FROM AUTHOR]

The combined morphological features of Stratiotes (Hydrocharitaceae) pollen, observed with light and electron microscopy, make it unique among all angiosperm pollen types and easy to identify. Unfortunately, the plant is (and most likely was) insect-pollinated and produces relatively few pollen grains per flower, contributing to its apparent absence in the paleopalynological record. Here, we present fossil Stratiotes pollen from the Eocene of Germany (Europe) and Kenya (Africa), representing the first reliable pre-Pleistocene pollen records of this genus worldwide and the only fossils of this family discovered so far in Africa. The fossil Stratiotes pollen grains are described and compared to pollen from a single modern species, Stratiotes aloides L. The paleophytogeographic significance and paleoecological aspects of these findings are discussed in relation to the Hydrocharitaceae fossil records and molecular phylogeny, as well as the present-day distribution patterns of its modern genera. [ABSTRACT FROM AUTHOR]

Frogs (Anura) are major components of tetrapod communities in the Neotropics and, according to divergence-time estimates, were already diverse in early Palaeogene times, but this is still poorly documented in the fossil record. A late Eocene frog assemblage from the Geste Formation exposed at Antofagasta de la Sierra (Catamarca province) is here described, providing a first glimpse into the Palaeogene anuran diversity in the present-day Puna of north-western Argentina. The assemblage is composed by at least four hyloid neobatrachian taxa having miniature to large body-sizes, ranging 17–81 mm estimated snout-vent length. Neither the families currently found in the Puna-Altiplano, nor those from the Cretaceous – Eocene of southern South America, are represented. The assemblage comprises possible brachycephaloids, odontophrynids, and hemiphractids, suggesting climatic and environmental conditions very different from the harsh conditions prevailing today in the Puna-Altiplano and a biogeographical link with Amazonia. The joint presence of these taxa is currently restricted to the nearby Austral Yungas and the Atlantic Forest, suggesting that the late Eocene frogs likely inhabited a humid forest. The new frog assemblage constitutes a rare window to the early evolution of Neotropical anurans and a major leap forward in the palaeoenvironmental reconstruction of the Puna during Eocene times. [ABSTRACT FROM AUTHOR]