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Water crickets of the subfamily Haloveliinae are semi‐aquatic bugs occurring in freshwater and marine habitats throughout the Indo‐Australian region, presently including six genera with more than 80 extant species. Whether lineage diversification in Haloveliinae is associated with the utilization of new ecological niches caused by transition events between freshwater and marine habitats remains poorly understood. We investigate the evolutionary history of Haloveliinae using large‐scale phylogenomic datasets and a set of novel redefined morphological characters based on 24 ingroup taxa representing all recognized genera. Our phylogenetic results based on the novel datasets definitively indicate that the freshwater genus Strongylovelia Esaki as currently defined is paraphyletic and supports the establishment of a new genus: Metavelia gen. nov., including three congeneric species: Metavelia patiooni comb. nov. (type species), Metavelia priori comb. nov. and Metavelia albicolli comb. nov. Reconstruction of ancestral habitats suggests a freshwater origin for the Haloveliinae. Divergence time estimations reveal that the origin of the monophyletic marine clade occurred at around 83 Ma (95% highest posterior density: 71–98 Ma) in the Late Cretaceous, involving a single transition event from freshwater to marine habitats. This time coincides with the period of high global sea levels in the Late Cretaceous. During this period, the marine incursions caused by the massive sea level rise flooded the continental margins, especially in Southeast Asia, where ancestral Haloveliinae were probably distributed. The appearance of new marine habitats after the marine incursions (e.g., intertidal, mangroves and estuarine) probably led to a subsequent establishment and diversification of the marine lineages. [ABSTRACT FROM AUTHOR]

Tetraodontidae is the most speciose family of Tetraodontiformes and is represented by fish popularly known as pufferfishes. They are characterized by modified jaws with four dental plates and the ability to inflate their bodies. Tetraodontids are distributed throughout the world and have a wide range of habitat use. One of its genera, Sphoeroides , shows a biogeographical pattern, with 19 of its 21 species restricted to coastal regions of the Americas. Although represented in large-scale phylogenies, the evolutionary history and biogeography of the genus have not been explored in detail. The present study aims to understand the historical and biogeographic processes that shaped the evolutionary history of Sphoeroides. Including samples from all biogeographic regions of its occurrence, we reconstruct a phylogenetic/biogeographic history hypothesis for the genus. Our results show that Sphoeroides is a paraphyletic group comprising Colomesus; indicate a central role of the biogeographic barriers of the Atlantic Ocean in the diversification of the genus; and identified a cryptic species in Brazilian waters, formally known as S. spengleri , described here through integrative taxonomy. We also propose nomenclatural changes given the position of Colomesus deeply nested within Sphoeroides. [ABSTRACT FROM AUTHOR]

The Cretaceous period was marked by significant transformations on Earth; paleoclimatic and paleogeographic changes were important parameters for the tectonostratigraphic evolution of the Brazilian sedimentary basins. The Parnaíba Basin in northern and northeastern Brazil is a syneclise, with a central sedimentary succession exceeding 3 km in thickness, containing sediments ranging from the Silurian-Devonian strata to the Cretaceous. The northwestern sector of the Parnaíba Basin, known as the Grajaú Basin, evolved from the breakup of Gondwana, with sediments of the Aptian-Albian age. In the present study, faciological, stratigraphic and biostratigraphic studies were conducted in the vicinity of the town of Grajaú, where the Codó Formation comprises three sequences: sequence I (shales and mudstones with organic material, siltites, limestones and ostracodal limestones), sequence II (gypsites), and sequence III (limestones). The faciological and biostratigraphic analyses of these sequences revealed the first known occurrence of calcareous nannofossils and planktonic foraminifera derived from the epicontinental sea that encroached the continent through the opening of the Brazilian equatorial margin and confirm the occurrence of a marine ingressions in the Codó Formation, which is recorded in sequences I and III. The biostratigraphic data, based on the identification of the S. varriverrucata (P-270), H. aptiana and M. miniglobularis (P. rhori /M. miniglobularis), and D. grandiensis (O-11) biozones, indicate that at least the studied section of the Codó Formation was deposited in the late Aptian. The biota identified in the study section are of Tethyan origin, and the faunal association dominated by palynomorphs, planktonic foraminifera, and calcareous nannofossils confirms the Tethyan origin of the formation. In this context, the marine ingressions were a clear result of the evolution of the Brazilian equatorial margin. • The Codó Formation is associated with the Sergipea variverrucata palynozone (P-270), which is restricted to the upper Aptian. • The detailing of the facies allowed the division into three sequences with lacustrine to marine depositional systems. • Calcareous nannofossils, foraminifera, ostracods and palynomorphs recorded an association typical of the upper Aptian. • Two marines ingression marked by the appearance of fauna characteristic of these environments. • Records of species from Tethys sea suggest a single entrance through the North in the Codó Formation. [ABSTRACT FROM AUTHOR]

Relationships between terrestrial formations in the central Latrobe Valley of southeastern Australia and coeval terrestrial and marine formations further to the east have been elucidated over the past several decades. In the Gippsland Basin's Latrobe Valley and Seaspray depressions, Eocene to Miocene fossils including rare foraminifera and more common dinoflagellates have been recovered from all five interseam sediments in the Morwell Formation, six interseam splits within the Traralgon Formation that includes age diagnostic Gippslandia extensa, and three interseams in the Alberton coal measures. The dinoflagellate assemblages generally are species-poor but do provide some age control and indicate episodic marine conditions within the Latrobe Valley Coal Measures. Some dinoflagellates may tolerate lower salinity near-shore waters, but above the Eocene acme of Gippslandia extensa are interpreted to indicate offshore conditions. The occurrence of dinoflagellates between seams of the Latrobe Valley and Alberton coal measures within the Gippsland Basin provides useful paleogeographic information, constraining paleo-shorelines. Fossils, including rare foraminifera and more common dinoflagellates, have been recovered from all five interseam sediments in Gippsland Basins Morwell Formation, six interseam splits within the Traralgon Formation and three interseams in the Alberton coal measures. Six interseam splits within the Traralgon Formation include the age diagnostic Gippslandia extensa, which indicates a late Eocene (latest Bartonian to Priabonian) age. Species of Spiniferites, Operculodinium and Hystrichokolpoma dominate in the coal interseams in the Morwell and Alberton formations (Oligocene and Miocene ages) and reflect typical species found in the Operculodinium Superzone of Partridge. The occurrence of dinoflagellates between seams of the Latrobe Valley and Alberton coal measures within the Gippsland Basin provides useful paleogeographic information, constraining paleo-shorelines. [ABSTRACT FROM AUTHOR]

Abstract Background The New World Tropics has experienced a dynamic landscape across evolutionary history and harbors a high diversity of flora and fauna. While there are some studies addressing diversification in Neotropical vertebrates and plants, there is still a lack of knowledge in arthropods. Here we examine temporal and spatial diversification patterns in the damselfly family Polythoridae, which comprises seven genera with a total of 58 species distributed across much of Central and South America. Results Our time-calibrated phylogeny for 48 species suggests that this family radiated during the late Eocene (~ 33 Ma), diversifying during the Miocene. As with other neotropical groups, the Most Recent Common Ancestor (MRCA) of most of the Polythoridae genera has a primary origin in the Northern Andes though the MRCA of at least one genus may have appeared in the Amazon Basin. Our molecular clock suggests correlations with some major geographical events, and our biogeographical modeling (with BioGeoBEARS and RASP) found a significant influence of the formation of the Pebas and Acre systems on the early diversification of these damselflies, though evidence for the influence of the rise of the different Andean ranges was mixed. Diversification rates have been uniform in all genera except one—Polythore—where a significant increase in the late Pliocene (~ 3 mya) may have been influenced by recent Andean uplift. Conclusion The biogeographical models implemented here suggest that the Pebas and Acre Systems were significant geological events associated with the diversification of this damselfly family; while diversification in the tree shows some correlation with mountain building events, it is possible that other abiotic and biotic changes during our study period have influenced diversification as well. The high diversification rate observed in Polythore could be explained by the late uplift of the Northern Andes. However, it is possible that other intrinsic factors like sexual and natural selection acting on color patterns could be involved in the diversification of this genus.

The Lower Cretaceous sediments of the Sanfranciscana Basin, southeast Brazil, are considered to have been deposited under a Gondwanan continental context. However, different authors have occasionally observed marine elements in these same deposits. This study analyzes samples from five sections of the Sanfranciscana Basin, Quiricó and Três Barras formations, to characterize the paleoenvironment around these marine incursions. We recovered continental (non-marine ostracods and palynomorphs) and marine microfossils (e.g., foraminifera, radiolarians, and ascidian spicules). The alternance of quartz-rich biogenic chert and claystone might be indicative of the occurrence of radiolarites in the studied sessions. The presence of the radiolarian genus Turbocapsula sp., the radiolarian species H o locryptocapsa fallax , and the palynomorph Tucanopollis crisopolensis enabled us to date the interval as early Aptian. Based on the lithologies and microfossils recovered, we interpreted the studied interval as a continental setting that was episodically subjected to marine incursions. We propose three successive paleoenvironmental scenarios: (1) an initial lacustrine depositional setting with a non-marine biota; (2) a second stage, characterized by the presence of episodic marine influence in the sedimentary succession (as evidenced by radiolarians, foraminifera and ascidians), and (3) the return to continental settings dominated by aeolian dune fields. These environmental scenarios characterize the initial development of the Central Segment of the South Atlantic Ocean. [Display omitted] • Microfossil evidence of marine incursions in the Sanfranciscana Basin, Brazil. • Tucanopollis crisopolensis and Holocryptocapsa fallax suggest early Aptian age. • Three environmental stages, from continental to marine and continental again. [ABSTRACT FROM AUTHOR]

Aim: Paleogeographic changes have had profound effects on the evolution and diversity of the Neotropical biota. However, the influence of marine incursions on the origin, diversification, and distribution of fishes is still incompletely understood. We investigate the biogeographical and chronological patterns of diversification for the marine‐derived Neotropical freshwater stingrays (subfamily Potamotrygoninae) at a continental scale. Location: Neotropics, South America. Taxa: Neotropical freshwater stingrays. Subfamily Potamotrygoninae (Myliobatiformes: Chondrichthyes). Methods: We generated a time‐calibrated phylogeny for 35 of the 38 valid species of Neotropical freshwater stingrays, from most of the major river basins of South America, using four genes. We used BEAST2 to determine the chronology of population and species divergence events, and "BioGeoBEARS" to infer historical biogeographic patterns. Results: The Potamotrygoninae originated during the early/middle Miocene in the upper Amazon region. We recover clades associated with particular geographic areas and detect a recurrent pattern of upper Amazon clades sister to clades in adjacent basins. The timing of dispersals from the upper Amazon to adjacent areas corresponds with the end of the Pebas wetlands. Lower Amazon and Shield associated taxa are relatively young. Main conclusions: We propose that the origin of the Neotropical freshwater stingrays is related to marine incursions that occurred during the Oligocene/Miocene. Subsequent diversification of Potamotrygoninae occurred in the Pebas wetland system in the upper Amazon with colonization of adjacent basins. These movements were generally unidirectional, with few lineages returning to the upper Amazon, and we speculate that ecological factors drove this pattern. We observed a burst of potamotrygonine diversification 5 Ma that appears to be related to the modern channelization of the Amazon Basin. [ABSTRACT FROM AUTHOR]

This study undertook the first investigation of malacosporean infections in Neotropical fish. We used polymerase chain reaction detection with a primer set generally targeting known malacosporeans to assay for infection in the kidney of 146 fish in 21 species belonging to 12 families collected from two areas in the Amazon Basin. Infections were found in 13 fish variously belonging to seven species in six families and included the first identification of a malacosporean infection in cartilaginous fish (a freshwater stingray). Based on ssrDNA, all infections represented a single Buddenbrockia species (Buddenbrockia sp. E) that demonstrates an exceptionally broad range of fish species infected, and countered our expectations of high Neotropical malacosporean diversity. Infections were characterized at varying and often high prevalences in fish species but sample sizes were small. Ascertaining whether highly divergent malacosporeans have not been detected by current primers, and more comprehensive sampling may reveal whether malacosporeans are truly as species poor in the Amazon Basin as present data suggest. Our results prompt speculations about evolutionary scenarios including introduction via marine incursions and patterns of host use over time. [ABSTRACT FROM AUTHOR]

Since the early exploration of the northern North Sea, Triassic sediments have been assigned to terrestrial depositional environments. Evaluation of core data from approximately one hundred wells in the Norwegian and UK sectors of the northern North Sea (58°-62° N), has challenged this interpretation. The sediments of the Smith Bank and Teist formations filled the deepest, syn-rift parts of the basin which in Early Triassic time were the areas closest to the Norwegian mainland, after which the centres of major subsidence shifted farther west. The mudstones of the Smith Bank and Alke formations formed as subaqueous, distal, fine-grained sediments in front of the proximal sand systems of the Lunde and Skagerrak formations. The latter accumulated as two major clastic wedges of deltaic sands derived from major valley systems emerging from the Sognefjord and Hardangerfjord/Boknfjord areas. Standing water was present during progradation of the depositional cones from the east. The depositional pattern was: alluvial to deltaic plain, delta front, subaqueous. Smaller volumes of sediment were shed off the western margin of the basin. The validity of the direct and indirect indicators of standing bodies of water, such as the rare marine and brackish-water fossils, laminae of micritic carbonate, clasts of finely laminated micritic limestone, subaqueous mass flows, wave ripples, intervals of mudstone with high GR readings correlated over semi-regional and regional areas, pyrite, possible submerged lacustrine sand flats and sabkha deposits, as well as the marine incursions into the central part of the basin during deposition of the Lunde and Skagerrak formations, are discussed. [ABSTRACT FROM AUTHOR]

Background: The New World Tropics has experienced a dynamic landscape across evolutionary history and harbors a high diversity of flora and fauna. While there are some studies addressing diversification in Neotropical vertebrates and plants, there is still a lack of knowledge in arthropods. Here we examine temporal and spatial diversification patterns in the damselfly family Polythoridae, which comprises seven genera with a total of 58 species distributed across much of Central and South America. Results: Our time-calibrated phylogeny for 48 species suggests that this family radiated during the late Eocene (~ 33 Ma), diversifying during the Miocene. As with other neotropical groups, the Most Recent Common Ancestor (MRCA) of most of the Polythoridae genera has a primary origin in the Northern Andes though the MRCA of at least one genus may have appeared in the Amazon Basin. Our molecular clock suggests correlations with some major geographical events, and our biogeographical modeling (with BioGeoBEARS and RASP) found a significant influence of the formation of the Pebas and Acre systems on the early diversification of these damselflies, though evidence for the influence of the rise of the different Andean ranges was mixed. Diversification rates have been uniform in all genera except one—Polythore—where a significant increase in the late Pliocene (~ 3 mya) may have been influenced by recent Andean uplift. Conclusion: The biogeographical models implemented here suggest that the Pebas and Acre Systems were significant geological events associated with the diversification of this damselfly family; while diversification in the tree shows some correlation with mountain building events, it is possible that other abiotic and biotic changes during our study period have influenced diversification as well. The high diversification rate observed in Polythore could be explained by the late uplift of the Northern Andes. However, it is possible that other intrinsic factors like sexual and natural selection acting on color patterns could be involved in the diversification of this genus. [ABSTRACT FROM AUTHOR]

The rainforests of Amazonia comprise some of the most biologically diverse ecosystems on Earth. Despite this high biodiversity, little is known about how landscape changes that took place in deep history have affected the assembly of its species, and whether the impact of such changes on biodiversity can still be observed. Here, we present a hypothesis to explain our observation that plants typical of Neotropical coastal habitats also occur in western Amazonia, in some cases thousands of kilometres away from the coast. Evidence on their current distribution, dispersal biology and divergence times estimated from molecular phylogenies suggest that these plants may be the legacy of the large marine‐influenced embayment that dominated the area for millions of years in the Neogene. We hypothesize that coastal plants dispersed along the shores of this embayment and persisted as inland relicts after the marine incursion(s) retreated, probably with the aid of changes in soil conditions caused by the deposition of marine sediments. This dispersal corridor may also have facilitated the colonization of coastal environments by Amazonian lineages. These scenarios could imply an unexpected coastal source that has contributed to Amazonia's high floristic diversity and led to disjunct distributions across the Neotropics. We highlight the need for future studies and additional evidence to validate and shed further light on this potentially important pattern. [ABSTRACT FROM AUTHOR]

We describe a new freshwater myxosporean species Ceratomyxa gracillima n. sp. from the gall bladder of the Amazonian catfish Brachyplatystoma rousseauxii ; the first myxozoan recorded in this host. The new Ceratomyxa was described on the basis of its host, myxospore morphometry, ssrDNA and internal transcribed spacer region (ITS-1) sequences. Infected fish were sampled from geographically distant localities: the Tapajós River, Pará State, the Amazon River, Amapá State and the Solimões River, Amazonas State. Immature and mature plasmodia were slender, tapered at both ends, and exhibited vermiform motility. The ribosomal sequences from parasite isolates from the three localities were identical, and distinct from all other Ceratomyxa sequences. No population-level genetic variation was observed, even in the typically more variable ITS-1 region. This absence of genetic variation in widely separated parasite samples suggests high gene flow as a result of panmixia in the parasite populations. Maximum likelihood and maximum parsimony analyses placed C. gracillima n. sp. sister to Ceratomyxa vermiformis in a subclade together with Ceratomyxa brasiliensis and Ceratomyxa amazonensis , all of which have Amazonian hosts. This subclade, together with other Ceratomyxa from freshwater hosts, formed an apparently early diverging lineage. The Amazonian freshwater Ceratomyxa species may represent a radiation that originated during marine incursions into the Amazon basin that introduced an ancestral lineage in the late Oligocene or early Miocene. [ABSTRACT FROM AUTHOR]

Opportunities to examine the structure of paleocommunities are extremely rare, due to the incompleteness of the fossil record. Regarding the Morro do Chaves Formation, there are many studies about the fauna and flora since 1870. However, paleoecological data are relatively scarce. According to the most recent study, the palynological records of the Morro do Chaves Formation were related to a disturbed paleoenvironment, caused by marine incursions in the northern sector of the Sergipe-Alagoas Basin during Lower Cretaceous. Thus, this paper aims to analyze the paleoecological relationships of the paleocommunity of fishes in the Morro do Chaves Formation, as the possible responses to the paleoenvironmental disturbances. From the basic matrix of abundance data for four fish orders found in 11 pelitic levels, similarity matrices were computed, using the Bray-Curtis distance coefficient. Cluster analysis by the unweighted pair-group method using arithmetic averages (UPGMA) was performed on these matrices, for grouping the levels. The advantages of multivariate analysis in paleoecological studies are also discussed. In addition, the Morro do Chaves Formation is composed of active piscivorous predators, benthophagous and planktiphagous fishes. The aulopiform fishes probably acted as top-down regulators in the paleocommunity, controlling the local fish populations. Mawsonia and " Lepidotes " are usually recorded in similar outcrops and inferred to be associated fauna. While Mawsonia likely possesses a sit-wait strategy, " Lepidotes " would be a relatively more active predator. • " Lepidotes " and Mawsonia are usually found together. • Aulopiformes, acted in the maintenance of the paleoichthyofauna. • " Lepidotes " would be relatively more active than Mawsonia. • Mawsonia could return to the marine environments. • The Morro do Chaves Formation was a constantly disturbed paleoenvironment. [ABSTRACT FROM AUTHOR]

Early Cretaceous sedimentary basins on the South Atlantic continental margins of South America and Africa are closely related with the Gondwana break-up, and record coeval paleoceanographic, paleoclimatic, and biotic changes during the late Barremian–Albian. The Sergipe-Alagoas Basin of northeastern Brazil contains one of the most complete Lower Cretaceous stratigraphic successions of the South Atlantic Ocean, including sedimentary and paleontological records nearly absent in nearby basins on the African/Brazilian continental margins. Fossil-rich sedimentary successions from the Sergipe-Alagoas Basin have allowed to assess: (i) evolutionary stages of the early South Atlantic Ocean; (ii) paleobiogeography of marine incursions (Austral and/or North Atlantic/Tethyan influences); and (iii) local signatures of global-scale paleoceanographic, paleoclimatic, and biotic events. Here we provide an overview on fossil-based biostratigraphic and paleoenvironmental studies of the Sergipe-Alagoas Basin, from the first marine incursions in a continental setting, to fully open-marine conditions. Based on eight fossil groups (ammonites, calcareous nannofossils, echinoids, planktonic and benthonic foraminifera, ostracods, palynomorphs, and radiolarians) from 107 sites, we observed that the marine biota shows strong affinity with Tethyan Realm in the Aptian–Albian interval, and provincialism/endemism is likely tied to the early-stage development of the South Atlantic Ocean. Based on late Barremian–late Albian lithological, paleontological, and geochemical data, we suggest three Sergipe-Alagoas Paleoenvironmental Stages (SAPSs): (i) continental conditions with possible episodic marine incursions (SAPS-1); (ii) transitional system, from continental to restricted-marine conditions (SAPS-2); (iii) transition from restricted- to open-marine conditions (SAPS-3). These local-scale evolutionary stages are correlated with early phases of the South Atlantic Ocean and major late Early Cretaceous paleoceanographic and paleoclimatic events. Moreover, we provide new approaches on the response of low-latitude biota to changing ocean circulation patterns in a hot, ice-free "greenhouse" world. • Sergipe-Alagoas Basin presents an Early Cretaceous complete marine succession. • Biostratigraphic and paleobiogeographic review about ammonites and microfossils. • Paleoenvironmental evolution since marine incursions to open marine. • Paleoceanographic stages of the early South Atlantic Ocean were presented. • Correlation between the stages with global scale paleoceanographic events. [ABSTRACT FROM AUTHOR]

• 24- n -propylcholestane was detected in Eocene sediments from western Qaidam Basin. • Biomarkers depict a hydrographically dynamic system driven by marine incursions. • Marine incursions in Qaidam Basin enlarged the eastern extent of Proto-Paratethys Sea. The easternmost extent of the large epicontinental Proto-Paratethys Sea is recorded in Eocene sediments of the Tarim Basin in western China. However, sporadic reports of marine-derived coccoliths in its eastern neighbor Qaidam Basin, which is conventionally considered to be an isolated lacustrine basin, cast doubt on this assumption. Here we present biomarker data on a core drilled in westernmost sector of the Qaidam Basin, which reveals the presence of 24- n -propylcholestane (24-npc) , a biomarker hydrocarbon derived from marine algae, whose patchy stratigraphic distribution chronicles the development of ephemeral marine conditions. Biomarker proxies reveal a dynamic system where the Qaidam Basin was in intermittent communication with the Proto-Paratethys Sea via the Tarim Basin during the middle Eocene after which it became hydrographically isolated as a shallow and stratified non-marine environment in the Late Eocene. [ABSTRACT FROM AUTHOR]

Abstract: This article describes marginal marine successions in the uppermost parts of the Pebas Formation, exposed along the Marañón River in Loreto, Peru. Six main facies associations are documented: (1) mud-dominated horizontal heterolithic couplets; (2) rooted brownish mud; (3) lenticular, mud-draped, cross-stratified sand; (4,5) mud- to sand-dominated, inclined heterolithic stratification; and (6) sand-dominated horizontal heterolithic couplets. The associations are interpreted as muddy, shallow, subaqueous flats/shoals, paleosols, secondary channels/run-off creeks, tidally influenced point bars, and shoreface deposits, respectively. Ichnoassemblages comprise a mixed Skolithos/Cruziana ichnofacies (including Thalassinoides, Skolithos, Taenidium, Planolites, Arenicolites, Chondrites, Teichichnus, and Scolicia), locally with elements of a continental trace fossil association (Planolites, Taenidium, and rhizoliths in the paleosols), which indicates that waters ranged from brackish through fresh to normal marine during the deposition of the uppermost Pebas beds. Palynological data from the point bar deposits include the diagnostic types Echitricolporites spinosus, Fenestrites spinosus, Magnastriatites grandiosus, Psiladiporites redundantis, Psilaperiporites minimus, Cyatheacidites annulatus, Verrucatosporites usmensis, and Monoporites annulatus. Their correlation with the Fenestrites and E. spinosus Palynological Zones suggests a Late Miocene age. The endemic Pebas mollusc fauna was not found in the deposits studied. The combination of locally strong bioturbation and environmental stresses (e.g. fluctuating salinity, low oxygen content and sedimentation rates) may have triggered synsedimentary carbonate dissolution at the sediment–water interface, which caused the dissolution or non-preservation of mollusc shells, if they were originally present. However, the possibility that the Pebas fauna was already extinct should be considered. Paleocurrent measurements at the channel/run-off creek deposits indicate NW-directed currents, suggesting a general ENE–WSW orientation of the paleocoastline. The deposits document the onset of the last major Miocene marine incursion in northern Peru. [Copyright &y& Elsevier]

The transition from Rotliegend to Zechstein within the Southern Permian Basin is one from continental desert to a marine environment. During the Upper Rotliegend II a huge playa lake existed there. This lake was temporarily influenced by precursors of the Zechstein transgression. Therefore the mega-playa evolved into a sabkha system. One of these early marine ingressions is known from an outcrop in Schleswig-Holstein. Laminated silt- and claystones, deposited within a standing water body, are intercalated in siltstones of a salt-flat environment. The lake sediments are characterised by high frequency cyclicity, shown by the sedimentary record and also by palaeontological data. The section contains fresh water as well as brackish-marine and marine fauna. Climatically forced cycles interact with marine incursions. After the Zechstein transgression had flooded the basin completely, sedimentation was controlled by sea-level fluctuations. Two sections, in the southern North Sea and in Schleswig-Holstein, are presented in this paper. Cyclicities with different frequencies controlled the sedimentation of the Kupferschiefer (T1) and the Werra Carbonate (Ca1). Sediments of the North Sea sequence were deposited within a shallow bay at the margin of an elevation. Therefore, the high frequency cyclicity became obvious within the sedimentary patterns and in the faunal content. [ABSTRACT FROM AUTHOR]

The dynamic environments of western Amazonia during the Neogene (23 to 2.58 million years ago [Ma]) included continental-scale wetlands that were episodically influenced by marine incursions originating from the Caribbean. The nature and frequency of such events is highly debated, with a general consensus on short events during the early (23 to 16) and middle (16 to 11.6 Ma) Miocene. However, scattered evidence for more events up until the late Miocene (11.6 to 5.3 Ma) exists. Based on a palynological analysis of borehole 1-AS-9-AM from the Solimões Formation (western Amazonia, Brazil), we provide further support for late Miocene marine influence in the region. Comparisons with other sites in the Solimões Basin indicate an age of earliest Tortonian (~11–10 Ma) for an assemblage with foraminiferal linings, acritarchs and dinocysts, totalling ~17.3% of the palynological count (n = 374 palynomorphs) at 34.10 m of depth. This is the topmost sample with a significant amount of marine indicators and its age is consistent even when different biostratigraphic interpretations are appreciated. Our data and comparisons also show that a larger proportion of sediments of the Solimões Formation should be placed within the late middle to early late Miocene. Our reconstruction of the Solimões deposits in the early Tortonian indicates intermintent low salinity regimes and a persistent connection with the paleo-Orinoco drainage until the closure of this connection in the late Miocene to Pliocene times. • New pollen data is presented from a borehole (1-AS-9-AM) in western Amazonia. • Graphic correlation was applied with two nearby sites, ages found from middle to late Miocene. • A thicker late Miocene section than previously interpreted is suggested. • A marine assemblage (~17% of the palynological count) at 34 m is composed of foraminiferal linings, dinocysts and acritarchs. • Regional comparisons support an early Tortonian episode of marine influence in a wide geographical area in western Amazonia. [ABSTRACT FROM AUTHOR]

Richly fossiliferous upper Oligocene to lower Miocene Patagoniense marine deposits constitute a conspicuous feature of the sedimentary record of most basins in Patagonia. Patagoniense meaning and subdivisions have been confusing, and correlation and elucidation of factors controlling sedimentation in a region as extensive as Patagonia are still highly debated. Our revision of the distribution, correlation, stratigraphic arrangement, and timing of deposition, allows redefining the Patagoniense as a succession of widely distributed marine sediments accumulated in Patagonia from ~25 to 15 Ma, showing different timing of accumulation for each basin. It can also be conceived as a higher rank stratigraphic cycle of relative sea-level fluctuation, which comprises two medium rank stratigraphic cycles spanning 2–4 Myr each, in turn enclosing several lower rank cycles of less than 1 Myr. The late Oligocene (~25-23 Ma) medium rank cycle shows deposits restricted mostly to the coastal area of Tierra del Fuego and Santa Cruz provinces in the Austral-Magallanes Basin, which respond to a combination of global sea-level fluctuations and flexural subsidence. The overlying early Miocene (~22-15 Ma) medium rank cycle comprises sediments deposited over extensive areas of Patagonia with a maximum flooding at 20-19 Ma suggesting, in addition to tectonic subsidence in the Austral-Magallanes Basin, regional long-wavelength subsidence and a global sea level component for this episode. The timing and thickness of the regressive part of this cycle show differences for each basin, suggesting the action of local sedimentary controls such as differential rates of sediment supply. Further geochronological and stratigraphic studies are necessary, especially for the northern exposures, which will allow improving time-constrained paleogeographic reconstructions. • Patagoniense deposits constitute a higher rank sedimentary cycle, developed from ~25 to 15 Ma. • Deposits include two medium rank (~2–4 Myr) and several lower rank (~1 Myr) cycles. • Cycles were strongly influenced by Andean orogenic processes in western Patagonia. • Synchronicity of maximum flooding suggests long-wavelength subsidence and a global sea level component. • Regressive deposits suggest local controls such as differential rates of sediment supply. [ABSTRACT FROM AUTHOR]

Several studies have reported Miocene shallow-marine incursions in the Pebas Megawetland system (Western Amazonia) based on paleontological and sedimentological evidence. Only a few publications restricted to Middle and Late Miocene fossils outcropping in the Iquitos (Peru), Benjamin Constant and Eirunepé (Brazil) areas have provided isotopic evidence to test these incursions. In this study, we present new carbon, oxygen, and strontium (87Sr/86Sr ratios) isotopic data of macrofossils (pacu and ray teeth, crab claws and oysters), and microfossils (ostracods and foraminifera) from reported lower to lower upper Miocene sedimentary rocks of Western and Eastern Amazonian (Peru and Brazil), mainly from shallow-marine deposits. It was also analyzed present-day organisms from distinct environments (beach, sea, riverine, and estuary) and compared these results with Miocene fossils. While C and O isotopic compositions indicate that Western Amazonia fossils display an isotopic composition similar to the present-day continental, limnic and riverine, environments (−17‰ to −5.61‰ for δ13C and − 10.14‰ to −1.92‰ for δ18O), Eastern Amazonia fossils display C and O isotopic compositions comparable to those from seawater environments (−2.53‰ to −0.72‰ for δ13C and − 4.85‰ to −1.76‰ for δ18O). We further used the 87Sr/86Sr isotopic composition of the fossils to estimate paleosalinity conditions. The 87Sr/86Sr isotopic compositions indicates that Eastern Amazonian water bodies of the Pirabas Formation (Marajó Basin) varied from mesohaline to marine conditions. In contrast, Early Miocene Western Amazonian water bodies of the Pebas Megawetland System (PMWS) are characterized by freshwater conditions. Nonetheless, in Middle and Early Late Miocene, oligohaline conditions are found in the Peruvian part of the PMWS. Paleosalinity estimates of the Brazilian part of the PMWS are less constrained and might indicate a salinity range between freshwater or oligohaline conditions. Our isotopic data suggest the PMWS was occasionally submitted to oligohaline conditions during Middle and Early Late Miocene shallow-marine incursions. We suggest that Miocene shallow-marine incursions in Western Amazonia at this time were characterized by transitional paleoenvironments, reconciling isotopic, sedimentological and paleontological evidences. • 374 Miocene Amazonian fossils attributed to shallow marine intervals analyzed. • Isotopic analyses of lower Miocene fossils from Eastern Amazonia indicate mesohaline to seawater conditions. • Isotopic data of middle and lower upper Miocene fossils from Peru yields oligohaline conditions in the Pebas Megawetland. • Marine incursions in Western Amazonia studied here occurred in transitional paleoenvironments with low seawater contribution. [ABSTRACT FROM AUTHOR]

• Two novel Ellipsomyxa species is described parasitizing the gallbladders of a fish from the Amazon basin. • Ellipsomyxa plagioscioni n. sp. is described parasitizing the gallbladders of Plagioscion squamosissimus. • Ellipsomyxa paraensis n. sp. is described parasitizing the gallbladders of Cichla monoculus. • The Amazonian Ellipsomyxa species do not have a monophyletic origin. • Marine incursion in the Amazon may have played an important evolutionary role in Ellipsomyxa genus. Species of the genus Ellipsomyxa Køie, 2003, parasitize mostly marine and brackish fish around the world. In the present study, we describe two novel species of Ellipsomyxa: Ellipsomyxa plagioscioni n. sp. parasitizing the gall bladder of Plagioscion squamosissimus (Sciaenidae), a freshwater fish but commonly found in brackish water in the Amazonian estuarine environment; and Ellipsomyxa paraensis n. sp. infecting Cichla monoculus (Cichlidae), a strictly freshwater fish. The host specimens were caught from the Amazon and Tapajós rivers, in the municipal region of Santarém, in the State of Pará, Brazil. The study was performed using a combination of morphological, biological, and SSU rDNA-based phylogeny, which suggested that marine transgressions of the Miocene epoch, in the central region of South America, were a pathway for the adaptation and radiation of these cnidarian parasites in the freshwater environment. Both disporic plasmodia and mature myxospores were found floating freely in the bile. Mature myxospores from both species were ellipsoidal in the valvular and sutural views, with thin smooth valves elongated in the direction perpendicular to the plane of the transverse sutural line. Ellipsomyxa plagioscioni n. sp. myxospores measured 11.1 (10.2–12.8) µm in length and 6.6 (5.6–7.6) µm in width. Two pyriform polar capsules discharging on opposite sides, some distance from both the sutural line and the spore ends, measured 3.8 (3.2–4.4) µm in length and 2.8 (2.3–3.3) µm in width, with 5–6 coil polar tubules. Ellipsomyxa paraensis n. sp. myxospores measured 11.5 (10.5–12.4) µm in length and 7.5 (6.6–8.6) µm in width. Two pyriform polar capsules which discharged on opposite sides some distance from both the sutural line and spore ends, measured 3.2 (2.1–3.9) µm in length and 2.6 (2.0–3.3) µm in width, with 2–3 coil polar tubules. Valvular protrusions were observed, associated with the tips of the polar capsules. Molecular analysis based on the SSU rDNA sequences indicated that the two novel Ellipsomyxa species were distinct from all other sequences deposited in the GenBank database. The phylogenetic trees clustered E. plagioscioni n. sp. as a basal species of a lineage of the marine/estuarine Ellipsomyxa , while E. paraensis n. sp. clustered together with other Amazonian species. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• The influence of marine incursions on South Yellow Sea Basin lacustrine source rocks was addressed. • Combined marine fossils and biomarkers corroborated marine incursions. • Marine incursion enhanced OM quality as indicated by HI and δ13C org values. • Marine incursion led to the preservation of a more homogenous OM. • South 4th Sag is preferred for the most promising hydrocarbon exploration of SYSB. The impact of marine incursions during transgression, on the quantity and quality of organic matter in lacustrine source rocks, is critical to understanding their source rock properties and therefore on their hydrocarbon generation potential, but is also challenging and controversial. Here we examine this issue based on a case study in the South Yellow Sea Basin (SYSB) offshore eastern China, addressing organic matter (OM) quantity, quality and petroleum generation kinetics. A total of 139 lacustrine source rock samples was collected from the fourth member of the Paleocene Funing Formation (E 1 f 4) in the SYSB, and investigated for organic petrographic and geochemical characteristics. The samples are immature to early oil window mature and the OM in all samples is dominated by terrigenous material, as shown by the organic petrography, relatively low hydrogen indices and biomarker distributions. The sediments are classified as inert to gas-prone. However, the presence of marine fossils (red and brown algae, coccolithophores and probably Neomonoceratinabullata) and the biomarker results, suggest that marine incursions occurred during the deposition of the lower unit of the E 1 f 4 (E 1 f 4 L). The samples from this unit display higher HI values and more depleted δ13C org ratios, but lower TOC and S 1 + S 2 contents, than the upper unit of the E 1 f 4 (E 1 f 4 U) source rocks without marine influence. This suggests that marine incursions primarily improved the quality, rather than quantity, of organic matter. Bulk kinetics indicated that marine incursions also led to a more homogenous OM and compositional kinetics and phase properties suggest that black oil is generated throughout the process of kerogen conversion. Thus, our data suggest that marine incursions had a positive effect on the OM quality and oil generation potential of these lacustrine source rocks. Therefore, the impact of marine incursions should be fully considered during source rock evaluation of coastal lacustrine basins, especially during high sea-level stages. In addition, the greatest hydrocarbon exploration potential is observed in the South 4th Sag of the Southern Depression and thus this study provides valuable data for shaping regional exploration strategy in the SYSB. [ABSTRACT FROM AUTHOR]