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Amynodontidae Scott & Osborn, 1883 are an extinct family of Rhinocerotoidea Owen, 1845 known from the middle Eocene to the latest Oligocene of Asia, North America, and Europe. We report here two unpublished specimens of Amynodontidae, a skull and a mandible of Zaisanamynodon borisovi Belyaeva, 1971 from the late Eocene of the Zaysan Basin (Kazakhstan) and a skull of Metamynodon planifrons Scott & Osborn, 1887, from the early Oligocene of the Big Badlands (United States). This new material has been incorporated into a morpho-anatomical character matrix. It was completed with the coding of the recently described species of Amynodontopsis jiyuanensis Wang X.-Y., Wang Y.-Q., Zhang R., Zhang Z.-H., Liu & Ren, 2020 and the revised coding of Cadurcotherium cayluxi Gervais, 1873 and Cadurcotherium minum Filhol, 1880. We computed a cladistic analysis based on this matrix, including 31 Rhinocerotoidea terminal taxa. The new phylogenetic hypothesis proposed allows to discuss the relationships of the referred specimens within Amynodontidae and those of Amynodontidae within Rhinocerotoidea. Our cladistic analysis clarifies the generic and specific composition of the tribes Metamynodontini Kretzoi, 1942 and Cadurcodontini Wall, 1982 and supports the monophyly of the genus Zaisanamynodon Belyaeva, 1971. The dichotomy between the two tribes is notably expressed by the presence of several cranial features such as "the deep nasal notch" or "the well-developed preorbital fossa" in Cadurcodontini. These cranial specializations attest to an adaptation of the peri-nasal region to the presence of a proboscis with a feeding function. Our study also opens a discussion on the biogeography of Amynodontidae, their emergence and dispersal in Asia and their subsequent migration to North America, and Eastern Europe. Their presence in Western Europe remains restricted to the Oligocene, after a dispersal related to the "Grande Coupure" event. [ABSTRACT FROM AUTHOR]

A new genus and species of Monotomidae, Rovnoeurops mckellari gen. et sp. nov., placed in the tribe Europini, is described and figured from Late Eocene Rovno amber. An extinct monotomid genus is documented in Cenozoic amber for the first time. Rovnoeurops gen. nov. can be distinguished from 27 extant genera of Europini by the combination of the following characters: distinct, short pubescence of dorsum, neck constriction behind eyes absent, short temples, stout antennae, 2-segmented antennal club, finely crenulate lateral pronotal margins, pronotum with median impression, regular elytral punctation, long femoral lines and intercoxal process of abdominal ventrite 1 widely rounded. [ABSTRACT FROM AUTHOR]

Premise of research. The Eocene fossil flora of the area around Vancouver, British Columbia, is poorly known despite work beginning in the 1890s to 1920s. The floristic character of the previously unstudied Burnaby Mountain flora from the Huntingdon Formation in British Columbia is reconstructed using plant megafossils and palynology. This site offers insight into the terrestrial vegetation and paleoclimate during the late middle to late Eocene of the Pacific Northwest of North America in a coastal setting during a global cooling trend. Methodology. Megaflora and microflora were identified, and the combined flora was compared with that of coeval floras from northwestern Washington. Paleoclimate was reconstructed from leaf morphology using the Climate Leaf Analysis Multivariate Program, leaf margin analysis, and leaf area analysis. A probabilistic nearest-living-relative approach was used to reconstruct paleoclimate independently of leaf morphology, using taxonomic identifications from both mega- and microfossils. These data were combined in an ensemble approach. Pivotal results. The Burnaby Mountain fossil flora is late middle Eocene to late Eocene in age and shares key plant taxa with the coeval Upper Ravenian flora of the Puget Group and the upper Chumstick Formation of northwestern Washington. The fossil flora contained a mix of subtropical and temperate forest elements, including rare palm and possible cycad leaf fragments, rare conifer pollen, and a diversity of broad-leaved trees. Conclusions. The reconstructed paleoclimate suggests humid warm-temperate to marginally subtropical conditions in coastal British Columbia during the late middle Eocene to late Eocene. An ensemble paleoclimate approach provided a most parsimonious mean annual temperature estimate of 16.2 ° C ± 3.1 ° C for the Burnaby Mountain fossils and mean annual precipitation of 134 ± 56 cm. A modern climatic analog is present on the East Coast of the United States in North Carolina, where palms are part of the native flora. [ABSTRACT FROM AUTHOR]

Fossil weevils of the subfamily Molytinae are currently represented by 103 species in 42 genera from 14 tribes. Fossil records of the tribe Aedemonini are known from the Eocene of Europe. This tribe makes up 22% of the London Clay weevil specimens identified to the genus level and 16% of the Curculionidae genera. At present, the distribution of this tribe is mainly paleotropical, but it was very prominent in the paratropical biota of the London Clay in the early Eocene, and it was still represented in the biota of the amber forests of Europe that retained some tropical elements in the Priabonian. A new species, Electrorhinus vlaskini n. sp., from the tribe Aedemonini of the subfamily Molytinae, is described from Rovno amber. It differs from E. friedhelmi in the smaller body size, finely faceted eyes, a coarser rugose pronotum, and sparser scales on the body. A list of the fossil Molytinae is compiled. This is the first record of a weevil of the subfamily Molytinae in Rovno amber, and the second finding of a representative of the genus Electrorhinus in the late Eocene and the third record of a species of Aedemonini preserved as a fossil. A key to European species of Molytinae with a rostral channel from Europe is given. [ABSTRACT FROM AUTHOR]

Lacewings (Neuroptera) have predatory larvae with highly specialised mouthparts. Larvae of many groups within Neuroptera are well represented as fossils preserved in ambers; however, larvae of some groups are less often reported in the literature. Here we report such a rare case, a larva of the group Hemerobiidae, an aphidlion, preserved in a piece of Eocene Baltic amber (about 40 million years old). It is preserved together with three possible prey items, wingless aphids, most likely representatives of Germaraphis (or at least closely related to this group). The aphidlion can be identified based on the morphology of the antennae, simple curved and toothless stylets, well developed labial palps, and the absence of other mouth-part structures such as a protruding labrum or maxillary palps. A long, club-shaped distal element of the labial palps identifies the specimen as a larva of Hemerobiidae. The aphids can be identified based on their very long, beak-like mouth parts. This find is, to our knowledge, the first example of a lacewing larva preserved together with its potential prey. We briefly discuss other cases in which fossils preserved in amber allow us to reconstruct aspects of behaviour and interactions of fossil lacewing larvae. [ABSTRACT FROM AUTHOR]

The importance of topography generated by Eocene Eurekan deformation as a sediment source for sandstones deposited on the western Barents Shelf margin is evaluated through a sediment provenance study conducted on wellbore materials retrieved from Spitsbergen and from the Vestbakken Volcanic Province and the Sørvestsnaget Basin in the southwest Barents Sea. A variety of complementary techniques record a provenance change across the Paleocene-Eocene boundary in wellbore BH 10-2008, which samples Paleogene strata of the Central Tertiary Basin in Spitsbergen. Sandstones containing K-feldspar with radiogenic Pb isotopic compositions, chrome spinel in the heavy mineral assemblage, and detrital zircons and rutiles with prominent Palaeoproterozoic and Late Palaeozoic—Early Mesozoic U-Pb age populations are up-section replaced by sandstone containing albitic plagioclase feldspar, metasedimentary schist rock fragments, a heavy mineral assemblage with abundant chloritoid, metamorphic apatite with low REE contents, metapelitic rutile with Silurian U-Pb ages and zircons with predominantly Archaean and Palaeoproterozoic U-Pb age populations. Our results clearly demonstrate the well-known regional change in source area from an exposed Barents Shelf terrain east of the Central Tertiary Basin during the Paleocene to the emerging Eurekan mountains west and north of the Central Tertiary Basin during the Eocene. Eocene sandstones deposited in the marginal basins of the southwestern Barents Shelf, which were sampled in wellbores 7316/5-1 and 7216/11-1S, contain elements of both the Eurekan and the eastern Barents Shelf provenance signatures. The mixing of the two sand types and delivery to the southwest margin of the Barents Shelf is consistent with a fill and spill model for the Central Teritary Basin, with transport of Eurekan-derived sediment east then south hundreds of kilometres across the Shelf. [ABSTRACT FROM AUTHOR]

In the central Atlas of Tunisia, numerous outcrops of the upper Eocene provide smectitic clays. A representative sample (A) which was collected from the El Gnater region round El Ala underwent mineralogical and physicochemical analyses (granulometry, DRX, BET, FT‐IR, etc.). This clay showing percentage of the order of 80% in smectite were activated with hydrochloric acid to improve its physicochemical properties, and consequently to increase their decolorization power for soybean oils. The best results were obtained using clay, activated with 3 N hydrochloric acid for 3 h at 75°C (AA2). Indeed, the specific surface area increased from 44 to 119 m2/g. The characterization of physicochemical properties was carried out on the samples (A: raw, AA: activated at different acid concentrations 1.5, 3 and 4.5 N at 75°C during 3 h). Under optimal conditions, the decolorization power of AA2 clay (60.15%) was found to be better than that obtained by a bleaching earth imported from Germany (57.27%). These encouraging results allow the reduction or permanently stopping of these materials imports. [ABSTRACT FROM AUTHOR]

A new genus and species of the braconid parasitoid subfamily Doryctinae, Eocenhecabolus kotenkoi gen. et sp. nov., from the late Eocene Rovno amber are described and illustrated. Eocenhecabolus gen. nov. is the first unambiguously extinct Doryctinae genus. This genus is described from the male and characterised by the followings features: in the fore wing by the postfurcal position of the recurrent vein (m-cu) relatively to the first radiomedial vein (2-SR), and a distally open brachial (second subdiscal) cell; in the hind wing by the presence of the elementary stigma-like enlargement on the distal half of the costal (1-SC+R) vein. The different types of stigma-like enlargements found in the hind wings of males in the subfamily Doryctinae are discussed. [ABSTRACT FROM AUTHOR]

Erosional scars, slumps, slides and debrites (mass‐transport deposits) on submarine slopes form relief that influences turbidity current behaviour. However, the interaction of mass‐transport deposit emplacement kinematics (i.e. rapid emplacement versus creep), the morphology of the evolving seafloor topography and subsequent flow types is complicated. This study describes two outcrop examples of deep‐water, predominantly turbiditic, deposits overlying mass‐transport deposits, from the Eocene slope succession of the Aínsa Basin (Spanish Pyrenees). In both examples, the mass‐transport deposit substrate continued to creep contemporaneously with turbidity current deposition and bypass. In the first case study, structures in the mass‐transport deposits are extensional and oriented parallel to flow. In the second, structures are compressional and oriented perpendicular to flow. Mudstones dominate the slope succession, but deposits overlying mass‐transport deposits form sandstone‐prone accumulations. Lateral confinement by flow‐parallel extensional faults enhanced channel‐formation. Channel incision occurred close to the exhumed fault plane on the hangingwall. Incision ceased as the fault gradually locked‐up, and channels avulsed to the hangingwall of a newly active normal fault, while the abandoned channel was filled by a thinning and fining‐upward succession. Barriers formed where the long axes of compressional anticlines developed in mass‐transport deposits formed perpendicular to flow. Here, turbidites filled the bathymetric lows in the axes of synclines. Continued tightening of synclinal depocentres led to repeated stoss side trapping and upslope accretion of coarse‐grained sediment accumulation. This generated thickening and coarsening‐up, followed by thinning and fining‐upward successions, tracking the decreasing, then increasing flow bypass associated with topographic expression on the mass‐transport deposit. This study shows how post‐emplacement creep, and orientation of topographic features on mass‐transport deposits, influence the routing and deposition of contemporaneous turbidity currents, and illustrates examples of facies successions that could be misinterpreted as the product of other autogenic submarine slope processes, such as lateral migration of sinuous channels, or compensational lobe stacking. [ABSTRACT FROM AUTHOR]

In this study, we present apatite fission-track results obtained for ten rock samples collected from three different areas across the Sierra Madre del Sur, southern Mexico. The central objective of our study is the timing of the exhumation event that took place in southern Mexico during Late Cretaceous–Palaeogene time. The thermochronometric data obtained during this work indicate that a Late Cretaceous–Eocene cooling is recorded within the Sierra Madre del Sur, and this is interpreted as resulting from exhumation, an orogenic event that is contemporaneous with the Laramide sensu lato (or the Mexican Orogeny). The fission-track ages become younger from west to east across the Sierra Madre del Sur, whereas the cooling rates also increased in the same direction approximately during Campanian–middle Eocene time. Here, we suggest that the activity of the major fault systems of southern Mexico, such as the Caltepec and the Oaxaca faults, played a primary role in the development of geological structures and the exhumation of the Sierra Madre del Sur. Active magmatism during the evolution of the Mexican Orogen implicates the subducted Farallon slab as the main driver of crustal thickening. Moreover, the possible influence of the eastward movement of the Chortis Block on the deformation of the Sierra Madre del Sur cannot be ruled out. [ABSTRACT FROM AUTHOR]

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Sedimentological and biochronological analyses were undertaken on carbonate deposits from 20 seamounts belonging to the Marcus–Wake Seamount Group, the Magellan Seamounts, and the Marshall Islands Seamounts in the JA area, northwestern Pacific Ocean. Deposition of carbonates on the JA seamounts varied markedly with age. The oldest carbonate deposits are Lower to middle Cretaceous shallow‐water limestones containing mollusks (including rudists), scleractinian corals, and calcareous sponges. Upper Cretaceous and Paleocene carbonates are rare, and no Oligocene carbonates may exist. In contrast, Eocene foraminiferal packstones are widespread, and Miocene–Pleistocene foraminiferal ooze covers the JA seamounts. The limited occurrence of Paleogene carbonate deposits on the JA seamounts is consistent with global observations (i.e., a paucity of Paleogene carbonates). The Cretaceous–Eocene carbonates have been phosphatized, whereas Miocene and later limestones have not. This fact, along with the results of previous studies, suggests that carbonate rocks on seamounts were phosphatized globally during the Oligocene. Upwelling of nutrient‐rich bottom waters during this time is likely responsible for the limited occurrence of Oligocene carbonate rocks on the JA seamounts. The thicknesses of the pelagic caps, which consist mainly of Miocene and younger foraminiferal oozes, varies among the seamounts and depends at least partly on the topography of the top of the seamount. [ABSTRACT FROM AUTHOR]

We describe a partial skeleton of a small bird from the lower Eocene London Clay of Walton-on-the-Naze (Essex, UK), which shows close affinities to two phylogenetically controversial early Paleogene taxa, Morsoravis sedilis (lower Eocene of Denmark) and Pumiliornis tessellatus (lower/middle Eocene of Germany). Our phylogenetic analysis supports a clade including M. sedilis, P. tessellatus, and the new species, Sororavis solitarius gen. et sp. nov., and this clade is introduced as Morsoravidae fam. nov. Even though morsoravids resulted within crown group Psittacopasseres in our analysis, as the sister taxon of the Zygodactylidae and Passeriformes, they exhibit a presumably plesiomorphic tarsometatarsus morphology unlike that of zygodactyl psittacopasserines. The elongate tarsometatarsus of S. solitarius shows a resemblance to that of extant mousebirds (Coliiformes) and has a large trochlea for the second toe, which bears an extensive trochlear furrow. This distinctive foot morphology is likely to represent an adaptation for a grasping foot and may indicate a locomotory behaviour similar to that of mousebirds, which are arboreal acrobats that forage in the foliage of trees and shrubs. Since the Psittacopasseres and the Coliiformes are widely separated in current phylogenies, the "mousebird-like" tarsometatarsus of the new species represents a notable instance of convergent evolution in small arboreal birds. [ABSTRACT FROM AUTHOR]

Bony fishes are among the best represented macrofossils from the earliest Eocene Fur Formation, northern Denmark. The most abundant fish of the formation has never been formally described, in spite of its abundance throughout the formation, and only referred to as an 'argentinoid'. This work provides a taxonomic study of this argentinoid taxon, which is described herein as Surlykus longigracilis gen. et sp. nov. The caudal skeleton shows separated first preural and first ural centra, a unique condition within the Argentiniformes. In addition, it is characterised by having a large mouth and a single supramaxilla, which suggest that Surlykus gen. nov. occupies a basal position within the Argentiniformes, representing the sister-group to all the other lineages of this clade ([Argentinidae + Opisthoproctidae] + [Bathylagidae + Microstomatidae]), and, consequently, a stem-group Argentiniformes. Mass-mortality assemblages may indicate that Surlykus longigracilis gen. et sp. nov. formed large schools in the ancient North Sea Basin, where it probably represented the trophic nucleus of the fish communities. [ABSTRACT FROM AUTHOR]

The presence of Cainozoic marine sediments in the Sperrgebiet, Namibia, was noted as early as 1908 when diamonds were found at Kolmanskop. Because of the economic interest of these deposits, geological investigations were undertaken, which led to detailed mapping of their distribution, initially by Beetz (1926). In the Central Sperrgebiet early investigators correlated the 'highest' beach deposits (ca 160 metres above present-day mean sea-level) to the Eocene, referred to in the old literature as 'Höchster Stand der Eocänsee' or the 'Eocäne Marine Inundation' (Kaiser, 1926). Liddle (1971) extended this « ancient » strandline a few kilometres northwards to Elfert's Tafelberg. Dingle et al. (1983) dated it to the late Palaeocene - early Eocene. In contrast, along the Namaqualand coastal plain in South Africa, marine deposits attributed by Pether (1986, 1994) to the 90 metre package, the 50 metre package, and the 30 metre package were correlated to the Miocene. Re-examination of the conglomerates at Eisenkieselklippenbake and Buntfeldschuh which crop out at ca 150-160 metres above sea level, reveals that some of the deposits are considerably younger than the Eocene, being instead of early Miocene (Aquitanian-Burdigalian) age. The beach conglomerates at both of these localities contain well-rounded and polished cobbles of densely ferruginised gravel and sand associated with cobbles of a great variety of other rock types (quartzite, silcrete, silicified freshwater limestone, vein quartz, agates, pebbles of banded ironstone formation (BIF), jasper etc.). The conclusion about the Miocene age of the beaches follows from the observation that the ferruginisation of near-surface deposits in the sector of the Sperrgebiet between Kerbehuk in the south and Elisabethfeld-Grillental in the north occurred during the Oligocene (more precisely, the Chattian) the process petering out during the Early Miocene (Aquitanian-Burdigalian), and ceasing altogether with the establishment of hyper-aridity in the region (onset of fully desert conditions in the Namib) ca 17 Ma. This means that cobbles derived from the break-up of the ferruginised deposits must be younger than the Chattian. Many of the cobbles of ferruginised sediment contain clasts of agate, BIF and jasper, vein quartz, silicified limestone etc. which were already present in the superficial deposits of the region prior to the Chattian, supporting the old conclusions concerning the presence of Eocene marine deposits in the Sperrgebiet. The revised age of the Eisenkieselklippenbake and Buntfeldschuh beach conglomerates means that the timing of the geomorphological development of the region, such as the back-cutting of the Buntfeldschuh Escarpment, requires revision, as do the correlations of near-surface deposits such as the fluvial Blaubok and Gemsboktal formations (Pickford, 2015) which are of Eo-Oligocene and Miocene age respectively. [ABSTRACT FROM AUTHOR]

The Palaeocene–Eocene Thermal Maximum (PETM) is one of the most important Cenozoic climatic events shaping modern biodiversity, yet reconstructions of its palaeobiomes remain controversial. Here we describe Gesomyrmex gallicus sp. nov., a new, extinct species of the ant genus Gesomyrmex Mayr, 1868, based on minor and major workers preserved in the early Eocene amber of Oise, France. Although there are only seven known extant species in the genus, all confined to warm and humid forests of SE Asia, the fossil record of Gesomyrmex indicates that the genus once radiated across Eurasia. The new species therefore provides direct evidence that this radiation likely co-occurred with the PETM. This observation constrains palaeoclimatic reconstructions of the Early Eocene by requiring the presence of an extensive, homogeneous and interconnected rainforest-like biome across palaeo-Eurasia, a scenario otherwise corroborated by pollen assemblages. The phases of regression of warm and humid forests and the widening of dry biomes probably occurred later during the Eocene, in between hyperthermals, and were probably less extensive than some computer models predicted. [ABSTRACT FROM AUTHOR]

New field observations and discovery of calcareous nannofossils and planktonic foraminifera from the 'shallow-marine' Çayraz Formation (Haymana Basin, Central Anatolia), a contributing Eocene section to the shallow benthic zonation (SBZ) in the Tethys, allow us to revise its stratigraphy and establish an integrated biostratigraphic scheme for the first time. The hemipelagic marls in the uppermost part of the Eskipolatlı Formation that underlies the Çayraz Formation yielded nannofossil assemblages of Zone CNE3, pinning down the initiation of the Çayraz shelf system into the 'middle' Ypresian. The prominent marly part (Member B) between the carbonate-clastic packages of the Çayraz Formation with prolific occurrences of larger benthic foraminifers (LBFs) (Members A below and C above) yielded calcareous nannofossils suggesting Zone CNE6 (late Ypresian). We show that the mixed carbonate-siliciclastic sequence with abundant LBFs in the upper part of the formation (Member C) is overlain by newly discovered hemipelagic marls (here named as Member D). These marls yielded calcareous nannofossils indicating Zone CNE9 and CNE10 for the lower and Zone CNE12(?Lutetian) for the upper samples. The same beds yielded planktonic foraminifers indicating Zone E8 for the lower and Zone E9 for the upper samples. We conclude that shallow-marine sedimentation in the Çayraz section ended in the 'middle' Lutetian, challenging the previous Bartonian records by LBFs. A new lithostratigraphic scheme consisting of four members with distinctive lithological and biotic characteristics is proposed for the Çayraz Formation: two main shelf systems (Members A and C), each followed by deep-marine sedimentation (Members B and D). [ABSTRACT FROM AUTHOR]

The timing and origins of the Early Cenozoic magmatic flare-up in southern Tibet remain controversial, mainly because of the lack of available data for the rare, small-volume, ocean island basalt (OIB)-like mafic rocks that can shed insights into this geological event. We have confirmed that Early Cenozoic OIB-like basalts in the Zhongba area, southern Tibet, were closely related to this magmatic flare-up, which occurred in response to deep mantle geodynamics. In this study, we present detailed geochronological and geochemical data for the Zhongba basalts. These Eocene (ca. 52 Ma) OIB-like basalts have negative K, Zr, Hf, and Ti anomalies, low Fe/Mn and high Fe/Zn ratios, and uniform and enriched Sr–Nd–Hf and HIMU-like Pb isotopic compositions (87Sr/86Sr(i) = 0.7052–0.7053; εNd(t) = − 1.7 to − 1.3; εHf(t) = − 1.1 to − 0.3; 206Pb/204Pb = 19.83–19.87), indicative of derivation from carbonated peridotite. Based on the regional tectonic evolution, we propose that the carbonated peridotite source of the Zhongba basalts was generated by the reaction between depleted mid-ocean ridge basalt-like mantle peridotite and melts from subducted Neo-Tethys carbonate-bearing oceanic crust. This carbonated peridotite was possibly preserved at the thermal boundary between the lithosphere and asthenosphere and underwent partial melting to produce the Zhongba basalts in response to slab break-off of the Neo-Tethys oceanic lithosphere at ca. 52 Ma. The slab break-off triggered the magmatic flare-up and other geological processes (e.g., a decrease in the velocity of the Indian Plate) in southern Tibet during the Eocene. [ABSTRACT FROM AUTHOR]

Abstract 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.

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 of the 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.

The Baiyun sag of the Pearl River Mouth Basin has become a focus for deepwater exploration with the highest hydrocarbon potential in northern South China Sea. The Eocene organic-rich mudstones are the main source rocks in the Baiyun sag, and the evolution of their depositional environment remains unclear. Based on the core and geochemical data, we investigated the depositional environments of the Eocene Wenchang and Enping sediments in the Baiyuan sag and revealed the sedimentary environment influences on the formation of the source rocks in the study area. The results indicate that the sediments of the Wenchang and Enping formations were deposited in dysoxic to oxic environments. Moreover, according to the concentrations of salinity-sensitive trace elements, and δ13C (-10.9‰ to -7.2‰, average -8.58‰) and δ18O (-18.4‰ to -14.5‰, average -17.1‰) values of carbonate cement in the sandstone samples, the Wenchang and Enping formations were in fresh water to brackish water conditions during their deposition, with increasing salinity from bottom to top, which suggests that the two formations were mainly deposited in lacustrine environment and the Enping formation experienced a relatively extensive lake transgression. The vertical variations of geochemical characteristics suggest that the Wenchang and Enping formations were deposited under a semi-arid/warm condition and all Eocene sediments experienced mild to moderate chemical weathering, relatively large detrital input and stable paleowater depth. Both primary productivity and preservation conditions played essential roles in controlling the enrichment of organic matters in the Baiyun sag, and the preservation conditions resulted from the restricted water setting. The present work provide a comprehensive analysis of depositional environments based on the abundance of high-resolution geochemical data. The results obtained reveal the dominated factors controlling organic matter enrichment in the Baiyun Sag of the Pearl River Mouth Basin. Those findings are not only significant for understanding the region’s paleogeography, but also provide guidance for future profitable oil and gas exploration in the northern South China Sea and other similar areas.

Northwestern Anatolia contains voluminous Cenozoic magmatic rocks which were emplaced during syn- to-post collisional stages of long-term crustal accretion and extensional stages since the late Paleocene. The Eocene to Late Miocene plutonic and volcanic rocks that are located throughout the Rhodopes, northern Aegean, and the western part of Western Anatolia show generally southward decreasing ages, coupled with an increasing crustal recycling component in their genesis. However, the early Eocene, ∼SW–NE-trending, mafic volcanic and the early Eocene, ∼NW-SE-trending, granitoid belts in the northeastern parts of Western Anatolia do not share these features. We present here new U-Pb zircon ages, whole-rock geochemical analyses, and Sr-Nd isotopic data from the early Eocene NW-SE-trending granitoid belt, together with age data from arc-related pyroclastics in the region, in an effort to resolve these uncertainties.The age data reveal that the post-collisional magmatism along the ∼ NW–SE-trending granitoid belt occurred ∼ 58–41 Ma; i.e. ∼ 30 Myr after the Pontide arc magmatism that was active from ∼ 92–74 Ma. We suggest that the ∼ SW–NE-trending mafic volcanic and the ∼ NW-SE-trending granitoid belts developed in response to break-off of two subducted slabs in the northern Neotethys. In addition, emplacement of the ∼ NW-SE trending granitoid belt may also have been influenced by a zone of weakness related to a series of NW–SE-trending dextral strike-slip shear zones lying from the Kapıdağ shear zone close to the Rhodopes in the NW to the Uludağ shear zone in the SE.

Basilosauridae, fully aquatic archaeocetes from the Eocene, had osteosclerotic or pachyosteosclerotic structure of ribs and, sometimes, other bones. Such a structure is far different from osteoporotic-like bones of modern cetaceans. A microanatomical and histological study was conducted on axial and limb skeleton of several basilosaurid specimens assigned to the genus Basilotritus, from Bartonian (late middle Eocene) deposits of Ukraine, remarkable for its pachyostotic bones. The postcranial skeleton of these specimens is a complex mosaic of diverse types of bone structure, which include pachyosteosclerotic, osteosclerotic and cancellous elements. The vertebrae have a pachyostotic layered cortex reaching its greatest thickness in the lumbar region. This cortex was strongly vascularized, and its layered structure is due to concentric circles mostly made by longitudinal vascular canals, in addition to cyclical growth lines. Heavy bones are concentrated in the dorsal and ventral areas. Swollen distal ends of thoracic ribs are interpreted as serving as ballast in the ventral area, as also previously proposed for Basilosaurus cetoides. Cortical bone tissue in vertebrae and ribs showed signs of intensive resorption and remodeling. This indicates the use of the axial skeleton not only for buoyancy control but also possibly for calcium and phosphorus recycling.

The late Middle Eocene Pondaung Fm. is a window to understand the environment and ecosystem dynamics of a past greenhouse world and the paleoenvironments where modern mammal clades such as anthropoid primates originated. Previous studies focused on the overall climate and vegetation of this Eocene habitat and provided first evidence for an early monsoon onset before the orogenesis of the Himalayan-Tibetan range. Here, we wanted to investigate how the mammal fauna used this habitat and which different ecological niches and microhabitats they occupied. We analyzed the carbonate fraction of dental enamel of a fossil mammal assemblage from various localities of the Pondaung Fm. in Myanmar. Bayesian niche modelling of the δ13C and δ18O values allowed us to quantify aspects of the ecological core niches occupied by these taxa, to calculate niche overlap and to use these data to infer directional competition potential in this mammal assemblage. Furthermore, comparison of different areas of the Pondaung Fm. revealed two different microhabitats whose distribution is consistent with existing vegetation models. Most primate taxa were found in both described environments, which gives a first indication about their ecological flexibility.

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.

A survey of the Eocene (Priabonian) Dry Branch Formation exposed in Aiken County, South Carolina, resulted in the collection of thousands of fossil teeth and bone fragments. Two sites located near the city of Aiken proved to be particularly productive, and 24 species of elasmobranchs, 11 osteichthyans, and three reptiles (one crocodilian and two turtles) have been identified. Herein we focus on the elasmobranch species (17 sharks and seven rays) that are part of the assemblage, which includes a new species of daggernose shark, Isogomphodon aikenensis n. sp. Cicimurri and Knight. The fossils are derived from the upper part of the Dry Branch Formation, and the fossiliferous strata accumulated within a high energy nearshore marine depositional environment that was influenced by a river system. Based on the vertebrate and invertebrate fossils we identified, the water depth was less than 40 m, and surface water temperature was at least 22° C . Elasmobranch species composition is similar to other late Eocene elasmobranch assemblages reported from the Gulf and Atlantic Coastal plains, particularly Georgia, and several of the taxa indicate affinities to the Tethyan region.

The warm-water (thermophilic) Eocene cassid gastropods reported previously from coastal southwestern North America (CSWNA), a region extending from the Olympic Peninsula, Washington to Baja California Sur, Mexico, are revised in terms of taxonomy, description, geographic distribution, and biostratigraphy. Five species of the cassine Galeodea and a single species of the phaliine Echinophoria are recognized. Galeodea meganosensis, G. sutterensis, G. louella, G. californica and G. tuberculiformis are predominantly found in California and, collectively, range in age from early to middle Eocene. Echinophoria trituberculata of middle Eocene age in southern California and of earliest late Eocene age in southwestern Washington, is the earliest known record of this genus. Several poorly known supposed cassids are discussed. The pre-Oligocene global record of Galeodea is compiled for the first time. The first arrival of Galeodea in the CSWNA region occurred in the early Eocene just after the warmest peak and highest sea level of the Cenozoic. Some of the CSWNA Galeodea species are very similar morphologically to some found in the Tethys Realm of Western Europe, especially in England and France, and to some found in the Gulf Coast and Mexico (Nuevo León and Chiapas). These similar species are indicative that the migratory route of Galeodea into the CSWNA region was via a current system that emanated from the Old World, passed near southern Western Europe, the Gulf Coast of the United States, northern and southern Mexico, and eventually influenced the CSWNA region. Thermophilic CSWNA cassids radiated during the early Eocene but declined by the end of the middle Eocene, and, because of global cooling, disappeared near the beginning of the Oligocene.

This article provides the first detailed description of the 25-m thick Cretaceous–Eocene section near the Mazanka village and its stratigraphic subdivision. The geological history of the Simferopol Uplift was unraveled by comparison with the outcrops of the Zuya quarry and the Bodrak River basin, facies analysis, and reconstruction of the sedimentation environments. The results obtained show that the Valanginian–Early Hauterivian silty and sandy deltaic deposits of the regressive sedimentation phase are concordantly overlapped by a transgressive sequence formed (from bottom to top) by sandy sediments of the coastal shallows, interlayering middle ramp clayey silts and sands, and outer ramp clays. Above the unconformity, a break of at least 70 Ma was registered from the Early Hauterivian to the Late Ypresian. The Upper Ypresian sediments dated by foraminifera were found to rest erosively on the Lower Hauterivian clays altered by the processes of subaerial soil formation. The Upper Ypresian lower part is formed by the transgressive lag of glauconite-quartz sandstones accumulated near the coast. Sandy marls with boulders of nummulitic limestones lie above, they must have formed in highly dynamic shallow marine conditions. The uppermost nummulitic limestones are the accumulations of large shells of benthic foraminifera driven to the bank by sea waves. It was concluded that the central part of the Simferopol Uplift was an island area until the end of the Early Ypresian. Its flooding caused the accumulation of coastal glauconite-rich sands, as well as carbonate sediments of the nummulitic bank at the later stages.

The larger-bodied fish fauna of the Kishenehn Formation’s Coal Creek Member (Eocene, 43.5 Ma), northwestern Montana, is understudied because of a sampling bias towards small specimens. Small specimens (

Introduction Subduction-related magmas are characterized by enrichment of large ion lithophile elements (LILEs), light rare earth elements (LREEs) and depletion in high field strength elements (HFSEs) (Harangi et al., 2007). These geochemical signatures of magmatic rocks are commonly explained by the addition of hydrous fluids from subducting oceanic lithosphere combined with the flux of melts from subducted sediments to the mantle wedge, lowering the mantle solidus and leading to magma generation (Aydınçakır, 2016). Asthenospheric mantle, subcontinental lithospheric mantle and/or lower crust may be the principal source of these rocks (Eyuboglu et al., 2018). In addition, magma differentiation processes, such as fractional crystallization, crustal contamination, and magma mixing may also play an important role in the genesis of these rocks. This research study presents new petrological and geochemical data from the volcanic rocks with NW–SE trending, which are situated in the northwestern margin of the Central –East Iranian Microcontinent (CEIM) (south-east of Khur, Isfahan Province) which have been formed during the peak activity of Eocene. Study of this typical small volume subduction- related magmatism will be useful in understanding the origin and geological evolution of the Central Iran in Cenozoic. Analytical Methods The petrographic investigations on Eocene volcanic rocks from the SE of Khur area were carried out with an optical microscope (Olympus-BH2) in the petrology Laboratory of the University of Isfahan, Iran. Major and trace element concentrations of samples from whole- rocks were obtained by a combination of inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) at the Als Chemex Laboratory of Ireland. The chemical compositions of 4 samples (B865, B866, B867, and B868) were determined by Neutron Activation Analysis (NAA) in the Isfahan Activation Center. The detection limit was 0.01% for all major element oxides and 0.01 ppm for rare earth elements. Mineral abbreviations were adopted from Whitney and Evans (2010). Results and Discussion Eocene volcanic rocks with trachy-basalt and trachy-basaltic andesite composition are exposed in the northwestern part of the Central-East Iranian Microcontinent (CEIM) (SE of Khur, Isfahan Province, Central Iran). These rocks which have a dominant northwest-southeast trend crosscut the Cretaceous sedimentary rocks. Petrography and mineral chemistry analyses indicate that the predominant rock-forming minerals of volcanic rocks are olivine, plagioclase, clinopyroxene and orthopyroxene. Phenocrysts set in a fine to medium grained matrix of the same minerals plus sanidine with minor amounts of opaque minerals. Secondary minerals are chlorite and calcite. The most common textures of these rocks are porphyritic, microlitic porphyritic, poikiolitic and glomeroporphyritic. Geochemical analyses of whole rock samples show that these rocks have been enriched in alkalies and large ion lithophile elements (Cs, K, Rb, Sr, Ba,), and have been depleted in high field strength elements (HFSE) (Ta, Nb, Ti). All samples indicate moderate to high fractionation in LREE patterns. These geochemical signatures point out to the subduction-related calc-alkaline nature of these rocks and their similarity to volcanic rocks of continental arcs or convergent margins (Yu et al., 2017). Pb enrichment and low values of Nb/La, Nb/U and Ce/Pb ratios reveal that crustal contamination has played an important role in magma evolution (Srivastava and Singh, 2004; Furman, 2007). The large volume of hydrous fluids coming from the subducted slab rather than sediments have caused enrichment and metasomatism of the subcontinental lithospheric mantle source. The geochemical characteristics of the studied rocks suggest that the parental magma have been derived from partial melting of a metasomatized spinel lherzolite of lithospheric mantle, which was previously modified by dehydration of a subducting slab. The tectonic environment, in which these rocks were formed has probably been a volcanic arc. Subduction of oceanic crust around the Central-East Iranian Microcontinent (CEIM) is the most reasonable mechanism which can be used to explain enrichment in volatiles of the mantle, and the calc-alkaline magmatism of the study area in Eocene times. Acknowledgments The authors thank the University of Isfahan for financial supports.

Vertically superimposed "red-greyish green" assemblages are developed in the first member of the Eocene Kongdian Formation (Kong1 member) in the Dongying sag of the Bohai Bay Basin, showing certain cyclic sedimentary characteristics.Inorder to better understand its depositional process and response to paleoclimate variation, the study took the Wang 46 well, which is located in the Wangjiagang area, as an example.Calibrated by the stratigraphic ages, cyclostratigraphy analysis has been conducted in the formation using cores, logging cuttings and gammaray(GR) curve to reveal its cyclic depositional process.The red beds correspond to flooded lacustrinemud and sandy beach deposited during flood events, while the greyish greenrhythm beds belong to the shallow lacustrine sand beach sediments in the intermittent wet period, and the two types of deposits are superposed with abrupt contacts.The continuous wavelet and spectral analysis of the GR curve indicate that the depositional process of the Ek1 member is controlled by the Milankovitch eccentricity and precession cycles, resulting in the thicknesses of the cyclically deposited formations are 39.4 m and 6.9 m, respectively.The "floating" astronomical time scale of the Ek1 member has been established by the band filtering of the 125 ka eccentricity cycle, and the Ek1 member is found to have 33 eccentricity cycles.The apparent average deposition rate changes between 0.236 m/ka and 0.408 m/ka.The eccentricity and precession cycles have controlled the depositional process: the maximum eccentricities mainly correspond to frequent occurrences of temporary lacustrine, on the contrary, it mainly developed flooded lacustrine.And, the temporary and perennial flooded lacustrine occurred during the periodsof minimum and maximum precessions, respectively.

The deeplying Mesozoic and Paleogene deposits of the Middle Kura depression have significant resource potential. They are the main complexes in terms of prospectivity for oil and gas exploration. The lithological-facies characteristics of the host rocks, accumulation of which is tectonically conditioned, are among major indicators responsible for their oil and gas content. Based on actual core material from parametric, prospecting and exploratory wells, along with downhole logging data the marker horizons have been established for individual exploration areas within the depression. An overview of the lithostratigraphic features and thickness distribution of the Upper Cretaceous and Eocene deposits is given. Distribution of the fluid conducting strata, regional variation of their reservoir properties in buried structures of the Middle Kura depression is addressed as well. Within the study area a typical Upper Cretaceous section is comprised of three genetic rock types: sedimentary, igneous-sedimentary and igneous. The Eocene sediments are represented by shaly (Lower Eocene), terrigenous-carbonate (Middle Eocene) and terrigenous (Uppere Eocene) lithofacies. The regularities that have been revealed in lithofacies and thickness variation enabled highlighting the areas of highest subsidence and sedimentation, tracing basinal limits in Late Cretaceous and Eocene ages and depicting them on the maps presented. The compiled schematic maps clearly demonstrate the paleorelief in the study area at the close of Late Cretaceous and Paleogene times. Sections of the indicated sedimentary complexes contain effusive, carbonate, sandstone and siltstone reservoirs, exhibiting substantial occurrence and thickness, the latter having a marked trend to increasing toward the centerline of the Lower Kura depression. Thus, it is likely that the alteration in facies within the Upper Cretaceous and Eocene sections is closely interrelated with the breaks in sedimentation and erosions, favouring for formation of traps controlled by diverse screening features. At basin scale the major regionally persistent seal horizons are the Maykop shales of Oligocene-Lower Miocene age, which in a number of cases unconformably cover petroleum containing horizons.

The middle Eocene Cibrone Formation of Brianza (central-western Lombardy) represents an important stratigraphic record to understand a key step of the tectonic evolution of the Alpine range poorly recorded elsewhere. Quantitative petrographic analysis of turbidite arenites, well-constrained in age by the biostratigraphy of interlayered marlstones based on calcareous foraminifera and nannoplankton, allowed us to identify a possible vertical compositional trend within the Cibrone Fm. and to document the NP17 nannofossil Zone (Bartonian) in central Lombardy exposures, east of the Ternate Formation outcrop area. Variable arenite compositions are interpreted to reflect contributions from different source areas, i.e., recycled orogen, island arc, and starved continental shelf. In a paleogeographic scenario still open to different interpretations, the proposed reconstruction supports a classical plate tectonics model for arc-trench systems. The stratigraphic gap, recorded everywhere in Lombardy, between the Eocene succession and the base of the Gonfolite Lombarda Group (upper NP24 nannofossil Zone, early Chattian), corresponds to the earliest stage of continental collision, uplift and erosion that climaxed in the Neo-Alpine Phase.

A new hyaenodont Maocyon peregrinus, gen. et sp. nov., is described based on a partial skull and associated mandible from the upper Eocene Youganwo Formation at Maoming locality in Guangdong Province, China. It shows certain similarities with the Hyainailouroidea in the skull structure, including anteroposteriorly extended jugal/squamosal suture, presence of a preglenoid crest, a lateral expansion of the squamosal posterior to the zygomatic arch, a transversally expanded mastoid process, a nuchal crest that does not extend laterally to mastoid process, and large occipital condyles. The phylogenetic analysis clusters the new taxon with Orienspterodon dahkoensis from the late middle Eocene of China and Myanmar and places this clade within the Hyainailouridae in a polytomy with the Apternodontinae and the Hyainailourinae.

During ontogenetic development, insects can undergo quite drastic changes (metamorphosis) until the adult stage is reached. A substantial part of this development in one group of Insecta, Holometabola, takes place during the pupa stage. Despite the pupa being recognised as an important phase, rather few depictions of pupae exist in the literature. We report here the first find of a fossil pupa of the lacewing group Mantispidae. The specimen represents an exuvia and is enclosed in Ukrainian Rovno amber, Eocene in age (c. 35–40 million years). We review the entire record of extant pupae of Mantispidae depicted in the literature or in online image repositories. With the aid of elliptic Fourier analysis, we compare the outline of the femur of the foreleg (raptorial appendage in the adults) of pupae and adults of Mantispidae. The pupae are all very similar concerning the femur, while the adults show a larger morphological diversity, particularly the extinct forms. Furthermore, our results indicate that the forelegs do not become increasingly complex throughout ontogenetic stages, but instead undergo an indirect development. According to the low variation in morphology seen in the pupa stage in Mantispidae, it is plausible that it represents a phylotypic stage for the group, i.e. a phase characterised by a significantly lower variability than other stages.

Two new laniatoreans from Eocene Baltic amber are described. Baltonychia obscura gen. et sp. nov. represents the first fossil Laniatores with a peltonychium on tarsus III--IV, implying that its closest living relatives are likely members of the extant families Cladonychiidae or Travuniidae. A second fossil is described as Insidiatores indet. as its preservation does not allow further assignment. Both fossils are substantially different to the so far only known Baltic amber laniatorean species Proholoscotolemon nemastomoides (Koch & Berendt, 1854), and suggest a more diverse Laniatores fauna in the Eocene of north-central Europe. The evolutionary history of the infraorder Insidiatores and their development into troglomorphic species is discussed. [ABSTRACT FROM AUTHOR]

†Antephilorhizus zerovae Kirichenko-Babko & Perkovsky sp. nov., the second species of this genus, is described from the Rovno amber (Ukraine). The new species is rather similar to the A. pripiatiensis Kirichenko-Babko & Perkovsky, 2021. The new taxon is compared with lebiines from Baltic amber. Based on a new data, the diagnosis of the genus †Antephilorhizus Kirichenko-Babko, 2021 is clarified and a key to both species of genus is given. [ABSTRACT FROM AUTHOR]

Studies of minute fossils trapped in amber shed light on the chronology of species and allow us to track evolutionary, ecological and biospheric changes. However, the resolution of commonly used methods for imaging amber fossils is limited, and the quality of preservation is not the only reason for this limitation. We have used super-resolution confocal laser microscopy (Airyscan) to study fossil mites (Acari) from the Eocene and Cretaceous amber (35–100 Ma). Here we report our technical approaches and methodological findings, including the selection of mounting medium, clearing of specimens, the effects of hydration of fossils in amber and the advantages of super-resolution confocal microscopy in obtaining images with sub-micron detail. Our results show that modern microscopy, in combination with specific non-destructive methods of amber preparation, can facilitate achieving image resolutions that were previously hardly feasible in fossils. [ABSTRACT FROM AUTHOR]

Hystricognath rodents arrived in South America from Africa during the Paleogene. The oldest South American rodents (Caviomorpha) were intensively studied in recent years. One of these assemblages is the caviomorph paleofauna from Santa Rosa, Peru. Their age was originally estimated as ?Eocene. Here, we report new caviomorph fossils from Santa Rosa and review the previously described rodents taking into account new dates and updated caviomorph information. We identified 18 genera and 22 species, including one new genus and species (Vucetichimys pretrilophodoncia gen. et sp. nov.), and two new species (Shapajamys minor sp. nov. and Ucayalimys amahuacensis sp. nov.). All taxa are brachydont, with visible cusps, and thin crests. The Santa Rosa rodents are one of the oldest and the most diverse caviomorph paleofaunas known from low latitudes of South America. Similarities between these caviomorphs and other Paleogene assemblages lead us to propose an early Oligocene age for those rodents from the Yurúa River (Brazil) and a close temporal relationship with the oldest known levels from Contamana. This new biochronological scenario has deep implications in the origin and early evolution of caviomorphs. A middle Eocene? entrance of one or several waves of African rodents arriving in South America is possible. [ABSTRACT FROM AUTHOR]

The role of the micro-facies and diagenesis was assessed to delineate the reservoir potential of the Early Eocene Margalla Hill Limestone, of the Shahdara section. The main focus of the study is the investigation and assessing the quality of the reservoir on the basis of diagenetic and depositional fabrics. Lithologically, the formation grades from thin to medium and massive bedded smaller to larger nodular limestone with sub-ordinate marl and shale inter-beds. Five micro-facies were established based on estimated allo-chemical and ortho-chemical constituent. The enumerated micro-facies include: Planktonic foraminiferal mud-wackestone (MHL-1); Lime mudstone (MHL-2); Lockhartia-rich mud-wackestone (MHL-3); Foraminiferal wackestone (MHL-4) and Bioclastic wackestone (MHL-5). These micro-facies are consistent with the deposition in the proximal outer ramp to proximal inner ramp settings of the gentle-sloping homoclinal ramp environment. The Margalla Hill Limestone is characterized by the fossil assemblages of mainly larger benthic foraminifera, such as Lockhartia, Assilina, Nummulites, rare Operculina, and Rotalia sp., and shallower fauna (echinoderms, algae and miliolids) and a few planktonic foraminifera including Morozovella cf. acuta, Globigerinatheka sp. and other Globogerinids. The fossil assemblages, allo-chemical and micritic constituents signify the depositional change from deep water toward the shallower setting, reflecting a coarsening upward trend during the deposition of the Margalla Hill Limestone. The Margalla Hill Limestone has been subjected to various diagenetic overprints which include micritization, cementation, neomorphism, compactions (mechanical and chemical), dissolution, dolomitization, and micro-calcite-filled fractures, representing early to syn- and post-depositional events. The diagenetic imprints of dissolution, micro-fractures, dolomitization enhance the reservoir characteristics, whereas cementation, micritization, neomorphism and chemical and mechanical compactions adversely affect the reservoir properties of the formation. In the Margalla Hill Limestone, the controlling factors of porosity and permeability distribution are attributed by depositional, diagenetic and deformational processes. [ABSTRACT FROM AUTHOR]

Eocene volcanic rocks with basaltic-trachyandesite and trachybasalt composition which cross-cut the Cretaceous sedimentary rocks, are exposed in the northwestern part of the Central-East Iranian Microcontient (CEIM) (SE of Khur, Isfahan Province, Iran). The rock-forming minerals of these volcanic rocks are olivine (chrysolite and hyalosiderite, Mg# = 0.69–0.71), clinopyroxene (augite with Mg# = 0.74–0.84), orthopyroxene (enstatite with Mg# = 0.61–0.62) and plagioclase (andesine and labradorite with An48.3-65.1). Phenocrysts set in a fine-grained matrix of the same minerals plus sanidine (Or59.1Ab36.6An4.3) with minor amounts of opaque minerals (magnetite and ilmenite). Secondary minerals are chlorite and calcite. The main textures of these volcanic rocks are porphyritic, microlitic porphyritic, poikilitic, and glomeroporphyritic. The Eocene volcanic rocks of the Khur area are characterized by SiO2 content of 51.8 to 54.9 wt %, Al2O3 amounts of 14.35 to 16.47 wt %, and TiO2 values of 0.88 to 0.92 wt %. They exhibit strong enrichment in light rare earth elements (LREE) relative to heavy REE (HREE) (La/Lu ratio up to 102.35), enrichment in large ion lithophile elements (LILEs), depletion in high field strength elements (HFSE), and present negative anomaly in Eu (Eu/Eu* = 0.72–0.87). Chemical characteristics and homogeneity of these volcanic rocks reveal their calc-alkaline nature and suggest that they were derived from a same parental magma and underwent a similar melt extraction. Major and trace elements geochemical features of the analyzed samples indicate that the parental magma was possibly derived from relatively low degrees of partial melting of a mantle wedge spinel lherzolite which was previously enriched by fluids/melts released from the Neo-Tethyan subducted slab. [ABSTRACT FROM AUTHOR]

The pan-sirenian Bauplan is conservative, probably owing to the constraints of adaptation to an aquatic lifestyle. Gathering morphological data from extinct forms is complex, resulting in poorly resolved phylogenies for stem pan-sirenians. Extant sirenians ossify the falx cerebri and the tentorium cerebelli, membranes of the dura mater of the brain attached to the parietal bone. Nevertheless, these ossifications are not present in some pan-sirenians. The basioccipital bone has received little attention in the literature except for establishing the relative age of individuals. Here, we present new cranial elements and a detailed description of the skull of Sobrarbesiren cardieli , a stem pan-sirenian from the Lutetian of Spain represented by eight individuals; we study its intraspecific variation and palaeoecological implications and explore the evolution of the endocranial structures and the basioccipital bone in pan-sirenians. Six new phylogenetic characters are added to the latest pan-sirenian dataset, resulting in a well-resolved topology where Sobrarbesiren is recovered close to the root, in a clade with Prototherium and Eotheroides aegyptiacum. The basioccipital bone and the ossified endocranial membranes have a phylogenetic signal, and the absence of such endocranial structures represents the plesiomorphic condition for pan-sirenians and is not diagnostic for the family Protosirenidae as previously believed. [ABSTRACT FROM AUTHOR]

Electronoyesella antiqua Simutnik, gen. et sp. nov., is described and illustrated based on a female specimen from late Eocene Rovno amber. Like most previously described Eocene Encyrtidae, the new taxon differs from the majority of extant ones in a number of features. Sclerotised metasomal structures, similar to the paratergites of extant Tetracneminae, are seen here for the first time in fossils. The new genus is characterized also by the frontovertex with four vertical rows of piliferous punctures and the face also with intricate sculpture; notauli are present as small but distinct depressions, only anteriorly; the apex of metatibia with a peg originating from a round, deep pit; and the unusual setation of the hind wing. [ABSTRACT FROM AUTHOR]

This study investigates the changes in paleoenvironmental conditions in the northern branches of the Neo-Tethys by employing geochemical proxies and shell data of larger benthic foraminifera (LBF) located in central Cappadocia. Three measured stratigraphic sections are studied from the Altipinar Formation (Boztepe Member), which is dated as middle Eocene. Three genera and five specieswere recorded as a result of the paleontological analyses, namely, Alveolina sp., Assilina exponens, Nummulites aturicus, Nummulites maximus and Nummulites perforatus. Composed of clayey sandy limestones, the Boztepe Member is represented by SBZ (Shallow Benthic Zones) 16-17 (late Lutetian/early Bartonian). In the Cappadocia region, a warming event was characterized by a temperature increase of 3°C to 4.5°C, and the warming started after 41.0 Ma (younger than the Lutetian /Bartonian boundary). The peak warming occurred around 40.0 Ma (early Bartonian). This period corresponds to the Middle Eocene Climatic Optimum (MECO), which was a significant global warming event. The findings of this study are confirmed by numerous studies that the global warming event occurred in the middle Eocene (between 41.8 and 39.7 Ma.). Additionally, while paleoenvironmental changes had no effect on the shell shape of Assilina exponens, they had a significant effect on the shell shape of Nummulites perforatus. The diameter/thickness ratio of benthic foraminifera tends to be smaller in shallowconditions than in deep conditions. Thiswas observed as their shell shapes becamemore spherical. [ABSTRACT FROM AUTHOR]

†Protosyngnathus sumatrensis is known from six specimens from Eocene lacustrine deposits of the Sangkarawang Formation of Sumatra, Indonesia. The fish was named almost 150 years ago, but has never been well described or figured. Probably because of this, it has not been included in phylogenies of extant pipefishes and seahorses (Syngnathiformes). A detailed description is provided, along with a new phylogenetic analysis of morphological characters that allows the Eocene fish to be confidently placed with the extant families Syngnathidae (pipefishes and seahorses) and Solenostomidae (ghost seahorses) along with the Paleocene marine fossil †Eekaulostomus cuevasae from Mexico. The vast majority of these fishes are marine inhabitants, with a few syngnathids entering brackish or freshwater habitats. †Protosyngnathus documents the occurrence of syngnathiform fishes in a lacustrine environment, indicating that this lineage invaded and became adapted to the freshwater environment early in the evolution of this group. [ABSTRACT FROM AUTHOR]