Salvinialean megaspores in the Late Cretaceous of southern Patagonia, Argentina

We report here two megaspores species related to the aquatic ferns of the Order Salviniales from the Late Cretaceous Mata Amarilla Formation (Austral Basin), southern Santa Cruz Province, Argentina. We identified the species Arcellites disciformis and Balmeisporites cf. B. holodictyus. The presence of A. disciformis, in particular, is significant not only because it represents the first record for the Southern Hemisphere, indicating a bi-hemispheric distribution for the species, but also because it increases the diversity of this genus in Patagonia. The new findings of salvinialean megaspores highlight the importance of water ferns in the Late Cretaceous aquiferous enviroments of southern South America. The common occurrences of Arcellites and Balmeisporites, whether in shallow, fresh or brackish water facies, indicates aquatic paleoenvironment of the Mata Amarilla Formation, as was inferred also from the sedimentological evidence. Their presence also indicates that the lower and middle levels of the Mata Amarilla Formation can be attributed to the megaspore Zone M3 (Albian–Cenomanian) defined for the Cretaceous of Patagonia

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

The rise of grasslands is linked to atmospheric CO2 decline in the late Palaeogene

Grasslands are predicted to experience a major biodiversity change by the year 2100. A better understanding of how grasslands have responded to past environmental changes will help predict the outcome of current and future environmental changes. Here, we explore the relationship between past atmospheric CO and temperature fluctuations and the shifts in diversification rate of Poaceae (grasses) and Asteraceae (daisies), two exceptionally species-rich grassland families (~11,000 and ~23,000 species, respectively). To this end, we develop a Bayesian approach that simultaneously estimates diversification rates through time from time-calibrated phylogenies and correlations between environmental variables and diversification rates. Additionally, we present a statistical approach that incorporates the information of the distribution of missing species in the phylogeny. We find strong evidence supporting a simultaneous increase in diversification rates for grasses and daisies after the most significant reduction of atmospheric CO in the Cenozoic (~34 Mya). The fluctuations of paleo-temperatures, however, appear not to have had a significant relationship with the diversification of these grassland families. Overall, our results shed new light on our understanding of the origin of grasslands in the context of past environmental changes.LP received a Marie Curie International Incoming Fellowships from the European Union for project GRASSLANDS (Proposal 329652 & 912652 ∣ FP7-PEOPLE-2012-IIF). Additional financial support was provided by ANPCyT and CONICET from the Argentinian Government. S.H. was supported by the Deutsche Forschungsgemeinschaft (DFG) Emmy Noether-Program HO 6201/1-1. This work was also supported by a BAYLAT-Anschubfinanzierung grant awarded to L.P. and S.H.Abstract Introduction Results and discussions Methods Data availability Code availability References Acknowledgements Author information Ethics declarations Peer review information Additional information Supplementary information Rights and permissions About this article This article is cited by Comment

Edad y paleoambiente de la Formación del Buey (Mioceno), sierra de Famatina, La Rioja, Argentina: evidencias sedimentológicas y palinológicas

Se analizan las facies y los paleoambientes sedimentarios de la Formación del Buey, sierra de Famatina, provincia de La Rioja. Se dan a conocer además, los primeros resultados palinológicos para esta unidad. La Formación del Buey está compuesta en forma mayoritaria por pelitas rosáceas a rojizas, con intercalaciones de conglomerados finos y conspicuos niveles carbonáticos, interpretados como depósitos fluviales entrelazados y lacustres. La asociación palinológica proviene de la facies lacustre, es poco abundante y diversa, y está integrada por polen, esporas y algas de agua dulce. El espectro polínico está compuesto por Podocarpaceae, probablemente alóctonas, Malvaceae, hierbas y arbustos mayormente xerofíticos y halofíticos de Chenopodiaceae, Ephedraceae, Convulvaceae y Asteraceae junto con formas de distribución tropical como Magnaperiporites (Convolvulaceae?) y Senipites (Symplocaceae). También se reconocen pteridofitas, briofitas y algas Chlorococcales (Pediastrum y Botryococcus). Especies de Malvaceae y Sparganiaceae/Thyphaceae constituirían la vegetación de un lago de agua dulce, un hábitat adecuado para el desarrollo de algas verdes planctónicas, en tanto que las formas restantes se habrían desarrollado en los márgenes del lago. El registro de especies xerofíticas y halofíticas, el desarrollo de calcretes y de yeso intrasedimentario, junto a la presencia de elementos tropicales sugieren condiciones semiáridas y temperaturas templado-cálidas a cálidas. Dataciones radimétricas recientes indican una edad miocena media para la Fm. del Buey; la evidencia palinológica es consistente con este rango temporal.Sedimentary facies and palaeoenvironments are described and interpreted from the del Buey Formation, Famatina Range, La Rioja Province. Miospores and algae are reported for the first time in this unit. The del Buey Formation is mainly composed by pinkish to reddish shales, some conglomerates, and conspicuous levels of mudstones, interpreted as braidplain and lacustrine deposits. The palynological assemblage, recovered from the lacustrine facies, is scarce and low-diversified. It is composed by probably allochtonous Podocarpaceae, together with Malvaceae and mostly halophytic-xerophytic herbs and shrubs of Chenopodiaceae, Ephedraceae, Convolvulaceae and Asteraceae, as well as tropical taxa such as Magnaperiporites (Convolvulaceae?) and Senipites (Symplocaceae). The assemblage also contains Pteridophyta, Bryophyta and Chlorococcales (Botryococcus and Pediastrum). Species of Malvaceae and Sparganiaceae/Thyphaceae would represent the vegetation of a freshwater lake, a habitat adequate to the development of planktonic green algae, whereas the remaining taxa could have developed in lacustrine marginal environments. The record of xerophytic and tropical taxa coupled with the development of calcretes and intrasedimentary gypsum suggest semiarid and warm to warm-temperate climate conditions. Recent isotopic data indicate a Middle Miocene age for the del Buey Formation, palynological evidence supports this temporal assignment.Fil: Barreda, Viviana D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Ottone, Eduardo Guillermo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Davila, Federico Miguel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología Básica y Aplicada. Cátedra de Estratigrafía y Geología Histórica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Astini, Ricardo A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología Básica y Aplicada. Cátedra de Estratigrafía y Geología Histórica; Argentin

A snapshot of mid Eocene landscapes in the southern Central Andes: Spore-pollen records from the Casa Grande Formation (Jujuy, Argentina).

The southern Central Andes-or Puna-now contains specialized plant communities adapted to life in extreme environments. During the middle Eocene (~40 Ma), the Cordillera at these latitudes was barely uplifted and global climates were much warmer than today. No fossil plant remains have been discovered so far from this age in the Puna region to attest to past scenarios. Yet, we assume that the vegetation cover must have been very different from what it looks today. To test this hypothesis, we study a spore-pollen record from the mid Eocene Casa Grande Formation (Jujuy, northwestern Argentina). Although sampling is preliminary, we found ~70 morphotypes of spores, pollen grains and other palynomorphs, many of which were produced by taxa with tropical or subtropical modern distributions (e.g., Arecaceae, Ulmaceae Phyllostylon, Malvaceae Bombacoideae). Our reconstructed scenario implies the existence of a vegetated pond surrounded by trees, vines, and palms. We also report the northernmost records of a few unequivocal Gondwanan taxa (e.g., Nothofagus, Microcachrys), about 5,000 km north from their Patagonian-Antarctic hotspot. With few exceptions, the discovered taxa-both Neotropical and Gondwanan-became extinct from the region following the severe effects of the Andean uplift and the climate deterioration during the Neogene. We found no evidence for enhanced aridity nor cool conditions in the southern Central Andes at mid Eocene times. Instead, the overall assemblage represents a frost-free and humid to seasonally-dry ecosystem that prevailed near a lacustrine environment, in agreement with previous paleoenvironmental studies. Our reconstruction adds a further biotic component to the previously reported record of mammals