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The article presents announcements by the Society of Systematic Biologists (SSB) including joining or renewing membership of the SSB, the journal having an Open Access option and Jacob S. Berv and Konstantinos Angelis winning the journals 2018 Publisher's award.

Published by Oxford University Press, on behalf of the Society of Systematic Biologists. Systematic Biology has an Open Access option. Copyright of Systematic Biology is the property of Oxford University Press / USA and its. [Extracted from the article]

In this paper, via a variational approach, we show the existence of periodic traveling waves for a Kadomtsev-Petviashvili-Boussinesq type system that describes the propagation of long waves in wide channels. We show that those periodic solutions are characterized as critical points of some functional, for which the existence of critical points follows as a consequence of the Mountain Pass Theorem and Arzela-Ascoli Theorem. [ABSTRACT FROM AUTHOR]

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Bruce Forbes Bohor, the 2011 Barringer Medalist of the Meteoritical Society (Glass, [1]), passed away at his home in Green Valley, Arizona, on November 17, 2019. Bohor, B. F. (1990) Shock-induced microdeformations in quartz and other mineralogical indications of an impact event at the Cretaceous-Tertiary boundary. Pollastro, R. M., and Bohor, B. F. (1993) Origin and clay-mineral genesis of the Cretaceous/Tertiary boundary unit, western interior of North America. [Extracted from the article]

Emiliani ([3]) remarked that the major factors affecting the evolution of plankton in the open ocean are not "mass extinctions", but rather the disappearance of single species followed by the appearance of new ones. Emiliani noted that in temporal sequences detected in oceanic sediment cores, one could observe the rapid disappearance of a single species, while other species within the same habitat were left unaffected. Emiliani stressed again the differences between "mass extinctions" and what he now called "background extinctions", which affect single species leaving other taxa unaffected and leading to that "extinctive evolution" he had defined 10 years before in his 1982 paper. [Extracted from the article]

The Bushe-Poladpur contact is one of the most important stratigraphic boundary separating the middle Lonavala Sub-group from upper Wai Sub-group in the Western Deccan Traps. In this paper, physical volcanology textural and petrochemical finger printing, crystal size distribution and shape preferred orientation studies (SPO) is integrated with paleomagnetic and AMS studies to correlate lavas across five localities transcending the Bushe-Poladpur boundary, south of Pune city. The flows belonging to the Bushe Formation are highly inflated, compound pahoehoe lavas, with plagioclase-olivine-phyric, coarse grained diktytaxitic textures. The flows belonging to the Poladpur Formation are transitional between pahoehoe and aa (rubbly pahoehoe lavas), with or without multi-tiered entablature showing fine-grained, olivine-phyric glassy textures. CSD studies indicate that the Bushe lavas have lower plagioclase crystals per unit area (1.11×10−4/µm2), low average effective nucleation rates (2.60× 10−12/µm3s) and high average effective growth rates (1.22×10−5µm2/s) for intact crust time than the Poladpur lavas that have higher plagioclase crystals per unit area (8.31×10−4/µm2), high average effective nucleation rates (3.46×10−11/µm3s) and lower average effective growth rates (2.24×10−6µm2/s) akin to their emplacement dynamics and cooling histories. There is a stark contrast in the magnetic susceptibilities (Bushe- 24759.8 × 10−6 SI; Poladpur-29178.02 ×10−6 SI) across the Bushe-Poladpur contact. There is a general similarity between the SPO of the primary silicates (plagioclase) to the AMS derived directions. The divergence in AMS directions across the Bushe-Poladpur contact in the study area can be attributed to complex interplay of local paleotopography and slope, lava flow field dynamics, inflation and inversion of topography, style and emplacement mechanism of flow units. Generalisations and over simplifications of delineating lavas and deciphering their flow direction on a single criteria (tool) or single ghat (road section), outcrop or sample will have disastrous consequences while mapping large and complex lava flow fields. Thus, a multi-disciplinary approach needs to be the norm for characterising, correlating and mapping lavas across formations that transcend the K-Pg boundary in highly dissected ancient continental flood basalt province like the Deccan Traps. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite making up one of the most ecologically diverse groups of living birds, comprising soaring, diving and giant flightless taxa, the evolutionary relationships and ecological evolution of Anseriformes (waterfowl) remain unresolved. Although Anseriformes have a comparatively rich, global Cretaceous and Paleogene fossil record, morphological datasets for this group that include extinct taxa report conflicting relationships for all known extinct taxa. Correct placement of extinct taxa is necessary to understand whether ancestral anseriform feeding ecology was more terrestrial or one of a set of diverse aquatic ecologies and to better understand avian evolution around the K-T boundary. Here, we present a new morphological dataset for Anseriformes that includes more extant and extinct taxa than any previous anseriform-focused dataset and describe a new anseriform species from the early Eocene Green River Formation of North America. The new taxon has a mediolaterally narrow bill which is rarely found in previously described anseriform fossils. The matrix created to assess the placement of this taxon comprises 41 taxa and 719 discrete morphological characters describing skeletal morphology, musculature, syringeal morphology, ecology, and behavior. We additionally combine the morphological dataset with published sequences using Bayesian methods and perform ancestral state reconstruction for select morphological, ecological and behavioral characters. We recover the new Eocene taxon as the sister taxon to (Anseranatidae+Anatidae) across all analyses, and find that the new taxon represents a novel ecology within known Anseriformes and the Green River taxa. Results provide insight into avian evolution during and following the K-Pg mass extinction and indicate that Anseriformes were likely ancestrally aquatic herbivores with rhamphothecal lamellae.. [ABSTRACT FROM AUTHOR]

Palaeontologists have long sought to explain the diversification of individual clades to whole biotas at global scales. Advances in our understanding of the spatial distribution of the fossil record through geological time, however, has demonstrated that global trends in biodiversity were a mosaic of regionally heterogeneous diversification processes. Drivers of diversification must presumably have also displayed regional variation to produce the spatial disparities observed in past taxonomic richness. Here, we analyse the fossil record of ammonoids, pelagic shelled cephalopods, through the Late Cretaceous, characterised by some palaeontologists as an interval of biotic decline prior to their total extinction at the Cretaceous-Paleogene boundary. We regionally subdivide this record to eliminate the impacts of spatial sampling biases and infer regional origination and extinction rates corrected for temporal sampling biases using Bayesian methods. We then model these rates using biotic and abiotic drivers commonly inferred to influence diversification. Ammonoid diversification dynamics and responses to this common set of diversity drivers were regionally heterogeneous, do not support ecological decline, and demonstrate that their global diversification signal is influenced by spatial disparities in sampling effort. These results call into question the feasibility of seeking drivers of diversity at global scales in the fossil record. Global trends in biodiversity are subject to regionally heterogeneous diversification processes. Here, the authors examine Late Cretaceous ammonoids, modelling the impact of sampling bias and potential biotic and abiotic drivers on our understanding of their biodiversity trends towards the Cretaceous-Paleogene boundary. [ABSTRACT FROM AUTHOR]

Ensign wasps (Hymenoptera: Evaniidae) develop as predators of cockroach eggs (Blattodea), have a wide distribution and exhibit numerous interesting biological phenomena. The taxonomy of this lineage has been the subject of several recent, intensive efforts, but the lineage lacked a robust phylogeny. In this paper we present a new phylogeny, based on increased taxonomic sampling and data from six molecular markers (mitochondrial 16S and COI, and nuclear markers 28S, RPS23, CAD, and AM2), the latter used for the first time in phylogenetic reconstruction. Our intent is to provide a robust phylogeny that will stabilize and facilitate revision of the higher-level classification. We also show the continued utility of molecular motifs, especially the presence of an intron in the RPS23 fragments of certain taxa, to diagnose evaniid clades and assist with taxonomic classification. Furthermore, we estimate divergence times among evaniid lineages for the first time, using multiple fossil calibrations. Evaniidae radiated primarily in the Early Cretaceous (134.1-141.1 Mya), with and most extant genera diverging near the K-T boundary. The estimated phylogeny reveals a more robust topology than previous efforts, with the recovery of more monophyletic taxa and better higher-level resolution. The results facilitate a change in ensign wasp taxonomy, with Parevania, and Papatuka, syn. nov. becoming junior synonyms of Zeuxevania, and Acanthinevania, syn. nov. being designated as junior synonym of Szepligetella. We transfer 30 species to Zeuxevania, either reestablishing past combinations or as new combinations. We also transfer 20 species from Acanthinevania to Szepligetella as new combinations. [ABSTRACT FROM AUTHOR]

A silicite horizon corresponding to the global catastrophic event at the Cretaceous–Paleogene boundary was found for the first time in the flysch sequence of the Shapsug section on the southern slope of the Northwest Caucasus. Assemblages of radiolarians and planktonic foraminifers dating the host beds were identified. Mineralogical and analytical data support the presence of tectites, impact minerals, and increased iridium content in the boundary bed of the studied section. [ABSTRACT FROM AUTHOR]

We apply fission-track thermochronology to shed new light on the tectonic history of Zealandia during Late Cretaceous continental extension and the onset of Late Tertiary mountain building in the Southern Alps of New Zealand. The Southern Alps are one of the fastest erosionally exhuming mountain belts on Earth. Exhumation of the Bonar Range in Westland just to the northwest of the Alpine Fault is orders of magnitude slower.We report apatite and zircon fission-track ages from samples that were collected along an ENE-WSW profile across the central Bonar Range, parallel to the tectonic transport direction of a prominent ductile fabric in the basement gneiss. Zircon fission-track (ZFT) ages show a large spread from 121.9 ± 12.1 Ma to 74.9 ± 7.2 Ma (1s errors). The youngest ZFT ages of 78 to 75 Ma occur at low elevations on either side of the Bonar Range and become older towards the top of the range, thereby showing a symmetric pattern parallel to the ENE-trending profile across the range. Age-elevation relationships suggest an exhumation rate of 50-100 m Ma-1. We relate the ZFT ages to slow erosion of a tectonically inactive spot in the Late Cretaceous magmatic arc of Zealandia. Therefore, the first main significance of the paper is that it demonstrates that not all of 110-90 Ma Zealandia was necessarily participating in extreme core complex-related extension but that there were enclaves of lithosphere that underwent slow erosion. The apatite fission-track (AFT) ages range from 11.1 ± 1.9 Ma to 5.3 ± 1.0 Ma and age-elevation relationships suggest an exhumation rate of c. 200 m Ma-1. We relate the AFT ages to the inception of transpressive motion across the Alpine Fault and modest exhumation in its footwall in Late Miocene times. If so, the second significant point of this paper is that transpressive motion across the Alpine Fault was already under way by c. 11 Ma. [ABSTRACT FROM AUTHOR]

Dale Russell described the osteology, morphology, and ecology of the small theropod "Stenonychosaurus inequalis" in two papers, speculating on its life habits, brain power, vision, movement, feeding, and hand capabilities. Russell even pondered a tool-using dinosauroid, the hypothetical troodontid descendant if the lineage had survived the Cretaceous–Paleogene extinction event. We revisit the life habits of the North American troodontids Troodon formosus and Latenivenatrix mcmasterae in part by reviewing various trace fossils of T. formosus discovered in Montana. These fossils include egg clutches, a nest, and recently discovered regurgitalites. We also contemplate the possibility of dinosaur tool use. Troodon likely constructed earthen nests in the same way that ratites and other birds did to create their nesting scrapes through backward hindlimb kicks. The more complex clutch architecture suggests dexterous movement of the eggs, potentially requiring manual manipulation. Functionally, reproductive traces support elevated body temperatures and a metabolic output that approach but do not equal that of modern birds. Brooding would require very high energy investment from the adult. The regurgitalites largely contain multi-individual aggregations of the marsupialiform Alphadon and support Russell's hypotheses of troodontids as crepuscular to nocturnal, intelligent, small game hunters with elevated metabolism and enhanced vision. Tool use in a few crocodilians and widely among extant birds suggests a reasonable possibility of this behavior in nonavian dinosaurs. Whether an avian-comparable encephalization quotient and freed forelimbs would make North American troodontids good candidates for exhibiting such behavior remains an open and speculative question. However, given the minimal modification made to tools by modern archosaurs, recognition of fossil tools poses a challenging problem. [ABSTRACT FROM AUTHOR]

A robust timetree for Mammalia was constructed using the time calibration function of BEAST v1.10.4 and MEGA 11. The analysis involved the application of times of the most recent common ancestors, including a total of 19 mammalian fossil calibration ages following Benton et al. (Palaeontologia Electronica, 2015, 1–106) for their minimum ages. Additionally, fossil calibration ages for Gorilla, Pan, and a geologic event calibration age for otters were incorporated. Using these calibration ages, I constructed a geologically calibrated tree that estimates the age of the Homo and Pan splitting to be 5.69 Ma. The tree carries several significant implications. First, after the initial rifting at 120 Ma, the Atlantic Ocean expanded by over 500 km around Chron 34 (84 Ma), and vicariant speciation between Afrotheria (Africa) and Xenarthra (South America) appears to have commenced around 70 Ma. Additionally, ordinal level differentiations began immediately following the K–Pg boundary (66.0 Ma), supporting previous hypothesis that mammalian radiation rapidly filled ecological niches left vacant by non‐avian dinosaurs. I constructed a diagram depicting the relationship between base substitution rate and age using an additional function in BEAST v1.10.4. The diagram reveals an exponential increase in the base substitution rate approaching recent times. This increased base substitution rate during the Neogene period may have contributed to the expansion of biodiversity, including the extensive adaptive radiation that led to the evolution of Homo sapiens. One significant driving factor behind this radiation could be attributed to the emergence and proliferation of C4 grasses since 20 Ma. These grasses have played a role in increasing carbon fixation, reducing atmospheric CO2 concentration, inducing global cooling, and initiating Quaternary glacial–interglacial cycles, thereby causing significant climatic changes. [ABSTRACT FROM AUTHOR]

Premise of research. A two-phase fern spike occurred immediately after the Cretaceous-Paleogene (K/Pg) mass extinction event. Solely on the basis of palynological evidence, researchers have traditionally attributed the first phase of this spike to the proliferation of a single species of a Cyathea -like fern in the earliest Danian. This traditional perspective is challenged by recent investigations linking Anemia -like fern foliage with Cyathidites spores at K/Pg boundary localities in the Raton Basin, where the fern spore spike was first discovered by R. H. Tschudy. Although evidence emerging from neighboring basins appears to corroborate this new perspective, it remains to be seen whether this generalization applies to the northern Great Plains. Methodology. A comprehensive list of the most common fern megafossils collected from earliest Danian plant localities across western North America was compiled to determine the number and potential identity of Cyathidites -producing ferns. Pivotal results. Three K/Pg survivors commonly collected from basal Paleocene strata in western North America conceivably produced psilate, trilete (Cyathidites) fern spores essentially identical to those observed at the K/Pg boundary fern spore spike: Anemia elongata (Newberry) Knowlton, Dennastra sorimarginata McIver et Basinger, and the Coniopteris -like fern "Dennstaedtia" americana Knowlton. Conclusions. Arborescent ferns were not among the first plants in western North America to thrive in the immediate wake of ecological collapse at the K/Pg boundary. Basal polypod ferns can be linked to Cyathidites spores in the northern Great Plains, perhaps because of a latitudinal climatic gradient. These results could explain taxonomic inversion in the dual-phase fern spore spike between western North America and New Zealand. [ABSTRACT FROM AUTHOR]

The eminent palaeontologist and Greenland explorer Claus Heinberg was born in 1945 and died in 2021 after prolonged illness. His scientific production was focused on two remarkably different subjects: the bivalve fauna of the Cretaceous-Palaeogene (K-T) boundary beds and the Mesozoic geology and stratigraphy of eastern North Greenland. He was employed at Roskilde University during most of his career until he retired in 2012. He was part of a cross disciplinary collaborative environment, comprising biologists, geographers, geologists, sociologists, civil engineers and architects. He was a highly engaged social debater of a wide spectrum of societal subjects throughout his life. He was a fine person, a good colleague and friend. [ABSTRACT FROM AUTHOR]

The Cretaceous-Paleogene (K-Pg) boundary interval represents one of the most significant mass extinctions and ensuing biotic recoveries in Earth history. Earliest Paleocene fossil mammal faunas corresponding to the Puercan North American Land Mammal Age (NALMA) are thought to be highly endemic and potentially diachronous, necessitating precise chronostratigraphic controls at key fossil localities to constrain recovery dynamics in continental biotas following the K-Pg mass extinction. The Laramide synorgenic sedimentary deposits within the Denver Basin in east-central Colorado preserve one of the most continuous and fossiliferous records of the K-Pg boundary interval in North America. Poor exposure in much of the Denver Basin, however, makes it difficult to correlate between outcrops. To constrain fossil localities in coeval strata across the basin, previous studies have relied upon chronostratigraphic methods such as magnetostratigraphy. Here, we present a new highresolution magnetostratigraphy of 10 lithostratigraphic sections spanning the K-Pg boundary interval at Corral Bluffs located east of Colorado Springs in the southern part of the Denver Basin. Fossil localities from Corral Bluffs have yielded limited dinosaur remains, mammal fossils assigned to the Puercan NALMA, and numerous fossil leaf localities. Palynological analyses identifying the K-Pg boundary in three sections and two independent, but nearly identical, 206Pb/238U age estimates for the same volcanic ash, provide key temporal calibration points. Our paleomagnetic analyses have identified clear polarity reversal boundaries from chron C30n to chron C28r across the sections. It is now possible to place the fossil localities at Corral Bluffs within the broader basinwide chronostratigraphic framework and evaluate them in the context of K-Pg boundary extinction and recovery. [ABSTRACT FROM AUTHOR]

The Deccan Volcanic Province has been considered as one of the largest magmatic regions, involving an aerial coverage of ca. 500,000 km2. It is subdivided into four sub-provinces, and holds a unique position in global tectonic models for understanding earth's geodynamics and the impact of voluminous eruptions on the contemporary biosystem and climate system. Published stratigraphic data suggest that volcanic eruption took place from 69 to 64 million years (Ma) ago when the Indian plate passed over the Réunion hotspot. The main phase of volcanic activity consisting of about 80% of total basaltic lava, erupted rapidly, during a short span (<1 Ma) or even less (two or three hundred thousand years), close to chron 29R, straddling to the Cretaceous–Paleogene (K–Pg) boundary. Recent high-precision age data show that the main volcanic phase is genetically linked to the Chicxulub impact and plume-head of the hotspot, and largely contributed to the end-Cretaceous mass extinction. To assess the links of the province to the K–Pg boundary, Chicxulub impact, Réunion plume, and Late Cretaceous global climate crisis, it is crucial to have a current state of knowledge of the understanding of its stratigraphy. A review of published data shows a surge in the province research that has considerably advanced the understanding of its stratigraphy. This province is intercalated with numerous infra- and intertrappean sedimentary beds that have yielded diverse biota, providing a reliable relative time control for duration of the volcanic activity. This paper presents a review of the stratigraphic developments of the province (lithostratigraphy, chemostratigraphy, magnetostratigraphy, and chronostratigraphy) from the very beginning to the present, and discusses the role of the Réunion plume in its formation. [ABSTRACT FROM AUTHOR]

The Žilina-Hradisko borehole in Slovakia intersects a succession from the Cretaceous Hradisko formation to the Paleocene Hričovské Podhradie formation. In this paper, we mainly focus on the Cretaceous–Palaeogene (K–Pg) boundary interval, which is marked by an abrupt change in planktonic biota and magnetic properties. Micropalaeontological findings suggest a rapid change from a stable, oxygen-rich, oligotrophic environment during the Maastrichtian to an unstable, cooler environment with reduced oxygenation and evidence of biotic stress in the lowermost Danian strata. An abrupt change in the magnetite concentration in the same interval indicates increased detrital input and probably biogenic (soft) magnetite production. Evidence recorded in borehole with enhanced Hg input into the Maastrichtian Ocean suggests that the Deccan eruptions mostly occurred prior to the K–Pg boundary, whereas no volcanic Hg input was detected at the K–Pg boundary itself. Double peaks in multiple magnetic properties mark the Danian hyperthermal Dan-C2 event, which was characterised by a series of environmental changes, including enhanced terrigenous input, oxygen deficit, increased nutrient supply, high benthic productivity, and Parasubbotina acme. Prior to the Latest Danian event, foraminiferal assemblages were significantly affected by dissolution and oxygen depletion, followed by warming, water column stratification, and diversification of calcareous plankton groups. An increase in detrital input and nutrient export drove the productivity of deep-dwelling subbotinids and globanomalinids and were correlated with the mid-Paleocene biotic event (MPBE). The seafloor biota associated with the MPBE implies oxygen deficiency and the prevalence of benthic infauna. The Selandian–Thanetian strata markedly differ from planktonic foraminifera of older formations, with their rich content of large, diversified, and heavily calcified morozovellid and igorinid foraminifera, revealing the existence of water column stratification with surface-water productivity and meso- to oligotrophic conditions. The microfauna of ornate morozovellids and benthic biota from the lowermost formation implies the onset of environmental stress and CaCO 3 dissolution during the Paleocene-Eocene Thermal Maximum (PETM). • unravelling the end-Cretaceous to early Ypresian palaeoenvironmental events in the Alpine Tethyan realm • K-Pg boundary recorded by an abrupt change in microbiota and magnetic properties in response to stressful palaeoenvironments • predominantly pre-K-Pg volcanic Hg input • Dan-C2 event: double peaks in multiple magnetic properties, Parasubbotina acme, high benthic productivity • environmental perturbations and biotic changes connected to LDE, MPBE and PETM [ABSTRACT FROM AUTHOR]

Yakubovichite, CaNi2Fe3+(PO4)3, a new mineral containing up to 20 wt% NiO, represents a novel type of terrestrial phosphate mineralization featuring an extreme enrichment in Ni. The mineral was discovered in the Hatrurim Formation (Mottled Zone)—pyrometamorphic complex whose outcrops are exposed in Israel and Jordan in the area coincident with the Dead Sea Transform fault system. Nickel-rich minerals in these assemblages also include Ni phosphides: halamishite Ni5P4, negevite NiP2, transjordanite and orishchinite—two polymorphs of Ni2P, nazarovite Ni12P5, polekhovskyite MoNiP2; Ni-spinel trevorite NiFe2O4, bunsenite NiO, and nickeliferous members of the hematite-eskolaite series, Fe2O3-Cr2O3 containing up to 2 wt% NiO. Yakubovichite forms polycrystalline segregations up to 0.2 mm in size composed of equant crystal grains, in association with crocobelonite, hematite, other phosphates, and phosphides. It has a deep yellow to lemon-yellow color, is transparent to translucent with vitreous luster, and has no cleavage. Mohs hardness = 4. Yakubovichite is orthorhombic, Imma, unit-cell parameters of the holotype material: a = 10.3878(10), b = 13.0884(10), c = 6.4794(6) Å, V = 880.94(2) Å3, Z = 4. Chemical composition of holotype material (electron microprobe, wt%): Na2O 1.82, K2O 1.76, CaO 6.37, SrO 0.49, BaO 1.37, MgO 2.13, NiO 21.39, CuO 0.16, Fe2O3 18.80, Al2O3 1.06, V2O3 0.44, Cr2O3 0.15, P2O5 44.15, total 100.09. The empirical formula calculated on the basis of 12 O atoms per formula unit is (Ca0.55Na0.29K0.18Ba0.04Sr0.02)1.08(Ni1.39Mg0.26Fe30.24+ V30.03+ Cu0.01Cr0.01)Σ1.94 (Fe30.90+ Al0.10)Σ1P3.02O12. Dcalc = 3.657 g cm–3. The strongest lines of powder XRD pattern [d(Å)(I)(hkl)]: 5.82(44)(011), 5.51(73)(101), 5.21(32)(200), 4.214(34)(121), 2.772(97)(240), 2.748(100)(202), 2.599(38)(400). Yakubovichite is the first mineral that crystallizes in the α-CrPO4 structure type. It has a direct synthetic analog, CaNi2Fe3+(PO4)3. Since yakubovichite is the first natural Ni-phosphate of non-meteoritic origin, the possible sources of Ni in the reported mineral assemblages are discussed. Pyrometamorphic rocks of the Hatrurim Formation were formed at the expense of the sediments belonging to a Cretaceous-Paleogene (Cretaceous-Tertiary) boundary (~66 Ma age). This geological frame marks the event of mass extinction of biological species on Earth that was likely caused by the Chicxulub impact event. The anomalous enrichment of pyrometamorphic assemblages in Ni may be related to metamorphic assimilation of Ni-rich minerals accumulated in the Cretaceous-Paleogene layer, which was formed due to a Chicxulub collision. [ABSTRACT FROM AUTHOR]

This paper describes the skull of the eusuchianAllodaposuchus subjuniperussp. nov. This new skull was recovered between the villages of Beranuy and Serraduy del Pon (Huesca, Spain). Stratigraphically, it was located in a level of coarse-grained sandstones in the middle-upper part of the lower red unit (Conqués Formation) of the Tremp Group, in the uppermost Maastrichtian close to the Cretaceous–Paleogene boundary. Until nowAllodaposuchuswas a monospecific genus. Phylogenetic analysis places the new taxon as a basal member of Eusuchia forming a clade with the other EuropeanAllodaposuchusremains and as a sister clade to the endemic European members of Hylaeochampsidae. Furthermore,Allodaposuchusand Hylaeochampsidae are within the stem of Crocodylia, being key taxa to understanding the origin of Crocodylia. The new taxon is the latest record ofAllodaposuchusfrom Europe, and it presents significant enough morphological differences fromAllodaposuchus precedensto establish a new species. The morphological variations in the material included inAllodaposuchus, the wide range of age and the geographical separation among the remains from Romania, France and Spain indicate thatAllodaposuchusis not a monospecific genus as traditionally established.http://zoobank.org/96CCE2FE-531A-4479-BE54-172D589D16A0 [ABSTRACT FROM PUBLISHER]

Aim The evolutionary history of bees is presumed to extend back in time to the Early Cretaceous. Among all major clades of bees, Colletidae has been a prime example of an ancient group whose Gondwanan origin probably precedes the complete break-up of Africa, Antarctica, Australia and South America, because modern lineages of this family occur primarily in southern continents. In this paper, we aim to study the temporal and spatial diversification of colletid bees to better understand the processes that have resulted in the present southern disjunctions. Location Southern continents. Methods We assembled a dataset comprising four nuclear genes of a broad sample of Colletidae. We used Bayesian inference analyses to estimate the phylogenetic tree topology and divergence times. Biogeographical relationships were investigated using event-based analytical methods: a Bayesian approach to dispersal-vicariance analysis, a likelihood-based dispersal-extinction-cladogenesis model and a Bayesian model. We also used lineage through time analyses to explore the tempo of radiations of Colletidae and their context in the biogeographical history of these bees. Results Initial diversification of Colletidae took place at the Late Cretaceous (≥ 70 Ma). Several (6-14) lineage exchanges between Australia and South America via Antarctica during the Late Cretaceous and Eocene epochs could explain the disjunctions observed between colletid lineages today. All biogeographical methods consistently indicated that there were multiple lineage exchanges between South America and Australia, and these approaches were valuable in exploring the degree of uncertainty inherent in the ancestral reconstructions. Biogeographical and dating results preclude an explanation of Scrapterinae in Africa as a result of vicariance, so one dispersal event is assumed to explain the disjunction in relation to Euryglossinae. The net diversification rate was found to be highest in the recent history of colletid evolution. Main conclusions The biogeography and macroevolutionary history of colletid bees can be explained by a combination of Cenozoic vicariance and palaeoclimatic changes during the Neogene. The austral connection and posterior break-up of South America, Antarctica and Australia resulted in a pattern of disjunct sister lineages. Increased biome aridification coupled with floristic diversification in the southern continents during the Neogene may have contributed to the high rates of cladogenesis in these bees in the last 25-30 million years. [ABSTRACT FROM AUTHOR]

In the first part of this review of the impact record of South America, we have presented an up-to-date introduction to impact processes and to the criteria to identify/confirm an impact structure and related deposits, as well as a comprehensive examination of Brazilian impact structures. The current paper complements the previous one, by reviewing the impact record of other countries of South America and providing current information on a number of proposed impact structures. Here, we also review those structures that have already been discarded as not being formed by meteorite impact. In addition, current information on impact-related deposits is presented, focusing on impact glasses and tektites known from this continent, as well as on the rare K–Pg boundary occurrences revealed to date and on reports of possible large airbursts. We expect that this article will not only provide systematic and up-to-date information on the subject, but also encourage members of the South American geoscientific community to be aware of the importance of impact cratering and make use of the criteria and tools to identify impact structures and impact deposits, thus potentially contributing to expansion and improvement of the South American impact record. [ABSTRACT FROM AUTHOR]

Abstract With increasing levels of atmospheric p CO 2 the oceans are becoming progressively more acidic, with the impact of a lowered pH beginning to affect the calcification of numerous invertebrate groups, including foraminifers, pteropods, heteropods and calcareous nannoplankton. Research on the ecology of foraminifera in the Mediterranean Sea, Gulf of California, Caribbean Sea and elsewhere has shown how modern assemblages are responding to acidification. Experimental work in mesocosms and laboratory cultures are also adding to our knowledge of the response to pH changes. Near Ischia (Italy), natural CO 2 vents amongst sea grass meadows are creating low pH environments in which it is possible to observe the response of benthic foraminifera. At a pH of 7.8 the foraminiferal assemblages are already becoming less diverse and below pH 7.6 there are often no calcite-secreting benthic foraminifera. In the Gulf of California, in a deeper-water setting, natural CO 2 (and methane) vents are also lowering sea floor pH. The foraminifera show the impact of this change, although the relatively high carbonate saturation ensures that calcite-secreting foraminifers are able to live and reproduce in these relatively low pH environments, only becoming impacted by dissolution effects once dead. Using data from the Cretaceous–Paleogene boundary in Texas, Alabama and north-west Europe it is clear that the plankton was severely impacted by surface water acidification while the relatively shallow water benthic foraminifera show little change and no visible signs of post-mortem dissolution due to ocean acidification. Highlights • This paper discusses the K/Pg in terms of surface water acidification caused by the K/Pg impact event. • describes depositional environments at K/Pg boundary • provides depositional model for the K/Pg boundary • provides correlaton of the boundary events [ABSTRACT FROM AUTHOR]

This paper presents new data on numerous small metallic particles of iron, copper, Fe-Ni, Fe-Ni-Co, and Fe-Cr alloys, magnetite, and aluminosilicate balls of cosmic origin found in the black clay boundary layer between the Cretaceous and Paleogene in the Stevns Klint Section (Denmark). The findings imply that a fall of an asteroid to Earth 65 Ma ago was accompanied with falling of finely dispersed metallic particles of extraterrestrial nature related to the asteroid fragments or to micrometeorites following the asteroid or to the intense supply of cosmic dust. The huge amount of finely dispersed matter that fell to Earth at that time should be considered in further reconstructions of events at the boundary of the Cretaceous and Paleogene. [ABSTRACT FROM AUTHOR]

The Ariyalur-Pondicherry sub-basin of the Cauvery basin comprises a near complete stratigraphic record of Upper Cretaceous-Lower Tertiary periods. Earlier studies have documented variations of clay mineral assemblages, change in microtexture of siliciclasts and many geochemical and stable isotopic anomalies far below the Cretaceous-Tertiary boundary (KTB) in these strata. This paper documents the occurrences of two positive 87Sr/86Sr anomalies preceding K-T boundary in this basin and discusses plausible causes. Analysis of trace elemental and stable isotopic profiles, sedimentation history, petrography and mineralogy of the rocks reveal that while both the anomalies may be due to increased detrital influx caused by sea level and climatic changes, the second anomaly might have been influenced by Deccan volcanism which in turn predated KTB. Record of such anomalies preceding K-T boundary supports the view of multi-causal step-wise extinction of biota across KTB. [ABSTRACT FROM AUTHOR]

Recent papers have opened the debate over whether the Chortís block was located off the coast of southern Mexico or in a more outboard position, and this led me to explore whether correlations with older structures could be established to determine the evolution of the southwest corner of the North America plate. In this paper I hypothesize that the Papalutla fault of Mexico and the Guayape fault system of Honduras, both considered to be terrane boundaries,were roughly continuous in the Cretaceous, extending from southern Mexico to the Chortís block. They influenced Early Cretaceous clastic sedimentation of the Zicapa Formation on the Guerrero-Morelos Platform (southern Mexico) and the Tepemechin Formation of the Central Chortís terrane (Honduras). The units accumulated in faultbounded basins associated with left-lateral slip. The basins developed in the Central Chortís terrane and Guerrero-Morelos Platform. Both geological entities appear to represent a continuous Cretaceous geologic province characterized by a trangression that occurred earlier in Honduras than in southern Mexico. This nonrotational hypothesis for the location of the Chortís block adjacent to southern Mexico during the Cretaceous is consistent with northeastward displacement of the Caribbean plate during Cretaceous time and implies 1500 km of Chortís block displacement during the Cenozoic. [ABSTRACT FROM AUTHOR]

This study aims to quantify the intensity and diversity of plant-insect associations observed in the fossil assemblage of Gelinden, Limburg, Belgium. The site yields a rich collection of well-preserved plant remains, mainly leaves, from a Paleocene European temperate forest. The 780 specimens presented here were scanned using standardized morphotype systems for any trace of damage. This raw data was then used to quantify the intensity and diversity of interactions in the Gelinden flora. This material showed an impressive richness of interactions, contrasting with the poor North American sites covering the period that followed the Cretaceous-Paleogene extinction. Both hosts and interaction types observed at Gelinden are two to three times more abundant than in most American floras, in raw numbers and leaf area affected. This is coherent with what has been observed in the few other studies conducted in Europe, South America and Antarctica, pointing toward more regionalized effects of the extinction than previously assumed based on American findings. This greater richness implies that these sites were either less affected or quicker to recover from the Cretaceous/Paleogene extinction, questioning its global impact, at least on the lower levels of the food web, as discussed in the following paper. • We provide quantitative data on plant-insect interactions observed in the Gelinden flora. • One of the few such study on a European locality. • Higher richness compared to similar age North American localities. • Supporting conclusion drawn from previous studies in France and South America. • Recovery from the K-Pg extinction was probably more regionalised than previously assumed. [ABSTRACT FROM AUTHOR]

A high-resolution analysis of the distribution of major and trace elements across a Cretaceous/Paleogene boundary (KPgB) was done using Laser Ablation-Inductivity Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and was compared with traditional distinct sampling and analysis. At the Agost site (SE Spain) a 22-cm-long core containing the KPgB was recovered using a Rolatec RL-48L drill. Within this interval, the lowermost 5 cm correspond to the Maastrichtian and the uppermost 17 cm to the Danian. The core section was resin-embedded under O 2 -free conditions, cut and polished for LA-ICP-MS continuous measurements with 10 μm increments and a laser-beam of 80 μm. Elemental concentrations in discrete samples taken prior to embedding from the same core interval were determined by Inductivity Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The LA-ICP-MS analyses in continuous mode considerably improve the resolution of geochemical profiles, allowing the compositional variability at a micrometer scale within the ejecta layer to be detected. In this study, we obtained profiles with 255 data points for the ejecta layer interval compared to 3 data points obtained by traditional manual sampling and ICP-OES analyses. Yet our recovered core section showed a rather limited preservation of the ejecta layer. This paper focuses on the presentation of LA-ICP-MS analysis as a particularly useful tool to investigate paleoenvironmental changes associated with bio-events. Additionally, the high-resolution of major and trace elemental distribution made it possible to study remobilization across thin but distinct boundaries such as the KPgB. [ABSTRACT FROM AUTHOR]

This work presents a detailed taxonomic study on the marine ostracods from the Paraíba Basin, northeastern Brazil, in wells from the wells Itamaracá-1IT-03-PE and Poty-1PO-01-PE, which record the Maastrichtian–Danian boundary. Besides the taxonomic data, this paper contributes to the paleoenvironmental knowledge of Cretaceous–Paleogene ostracods from the Paraíba Basin. The analysis of 98 samples of the well Itamaracá-1IT-03-PE and 59 samples of the Poty-1PO-01-PE resulted in the record of 34 ostracode species, all representative of a marine environment with normal salinity. Seven new species are proposed: Cytherella centrocompressa sp. nov.; Cytherella paraibensis sp. nov.; Neonesidea potyensis sp. nov.; Bythoceratina spinosa sp. nov.; Eucytherura ventrotuberculata sp. nov.; Langiella fauthi sp. nov. and Protobuntonia punctatum sp. nov. [ABSTRACT FROM AUTHOR]

Orchidaceae (with >28,000 orchid species) are one of the two largest plant families, with economically and ecologically important species, and occupy global and diverse niches with primary distribution in rainforests. Among orchids, 70% grow on other plants as epiphytes; epiphytes contribute up to ~50% of the plant diversity in rainforests and provide food and shelter for diverse animals and microbes, thereby contributing to the health of these ecosystems. Orchids account for over two‐thirds of vascular epiphytes and provide an excellent model for studying evolution of epiphytism. Extensive phylogenetic studies of Orchidaceae and subgroups have ;been crucial for understanding relationships among many orchid lineages, although some uncertainties remain. For example, in the largest subfamily Epidendroideae with nearly all epiphytic orchids, relationships among some tribes and many subtribes are still controversial, hampering evolutionary analyses of epiphytism. Here we obtained 1,450 low‐copy nuclear genes from 610 orchid species, including 431 with newly generated transcriptomes, and used them for the reconstruction of robust Orchidaceae phylogenetic trees with highly supported placements of tribes and subtribes. We also provide generally well‐supported phylogenetic placements of 131 genera and 437 species that were not sampled by previous plastid and nuclear phylogenomic studies. Molecular clock analyses estimated the Orchidaceae origin at ~132 million years ago (Ma) and divergences of most subtribes from 52 to 29 Ma. Character reconstruction supports at least 14 parallel origins of epiphytism; one such origin was placed at the most recent common ancestor of ~95% of epiphytic orchids and linked to modern rainforests. Ten occurrences of rapid increase in the diversification rate were detected within Epidendroideae near and after the K‐Pg boundary, contributing to ~80% of the Orchidaceae diversity. This study provides a robust and the largest family‐wide Orchidaceae nuclear phylogenetic tree thus far and new insights into the evolution of epiphytism in vascular plants. [ABSTRACT FROM AUTHOR]

New decapod crustaceans from ?Selandian to Thanetian strata of the Kambühel Formation, Austria, include the paguroid Squamipelta insecta new genus and species, and two new galatheoid species, Protomunida kambuehelensis and Annieporcellana paleocenica. The range of Annieporcellana is extended across the Cretaceous-Paleogene boundary. Selandian and Thanetian decapod occurrences are rare; thus, this report adds to the known decapod diversity in the recovery after the end-Cretaceous events. [ABSTRACT FROM AUTHOR]

We present the first dated molecular phylogeny of the Cerurinae moths (Notodontidae), based on sequence data for 666 loci generated by anchored hybrid enrichment. Monophyly of Cerurinae is corroborated, which includes the following genera: Pararethona Janse, Pseudorethona Janse, Oreocerura Kiriakoff, stat. rev. , Cerurella Kiriakoff, Notocerura Kiriakoff, Hampsonita Kiriakoff, Afrocerura Kiriakoff, Cerurina Kiriakoff, Neoharpyia Daniel, Furcula Lamarck, Neocerura Matsumura, Americerura St Laurent and Goldstein, gen. nov. , Cerura Schrank, and Kamalia Koçak & Kemal. The type species of the Neotropical genus Tecmessa Burmeister , T. annulipes (Berg), which had been incorrectly assigned to Cerurinae, is recovered in Heterocampinae; and Americerura gen. nov. is proposed to receive 17 unambiguously cerurine species transferred from Tecmessa. Divergence time estimates recover a crown age of Notodontidae roughly coincident with the K-Pg boundary, and a late-Oligocene crown age for Cerurinae. An African origin is inferred for Cerurinae, followed by colonization of the Palearctic, the Americas, Indomalaya, and Australasia during the Miocene. At least three independent colonizations of the Americas are inferred, one in the mid-Miocene associated with ancestral Americerura gen. nov. and two in the Pliocene and Pleistocene within Furcula. We hypothesize that the global spread of Cerurinae was enabled by that of its primary caterpillar foodplants in the Salicaceae. State-dependent diversification analyses suggest that cerurines diversified most rapidly in temperate climates. [ABSTRACT FROM AUTHOR]

Reconstructing deep-time biogeographic histories is limited by the comparatively recent diversification of most extant lineages. Ray-finned fishes, which include nearly half of all living vertebrates, are no exception. Although most lineages of ray-finned fishes radiated around the Cretaceous-Paleogene boundary, a handful of ancient, species-poor clades still persist. These lineages can illuminate very old biogeographic trends, but their low species richness can also limit the reconstruction of these patterns. The seven extant species of gars distributed in freshwater habitats in North America and Cuba are an old clade with a fossil record spanning over 150 million years of Earth history. Using a genomic data set of DNA sequences of 1105 exons for the seven living species and an updated morphological matrix of all extant and extinct taxa, we infer the phylogenetic relationships of gars and test how divergence times and biogeographic reconstructions are influenced by sequential and joint estimation and the effect on these inferences when using different taxon sets based on fossil completeness. Our analyses consistently show that the two extant gar genera Atractosteus and Lepisosteus diverged approximately 105 million years ago and many of the inferred divergences in the gar time-calibrated phylogeny closely track major Mesozoic tectonic events, including the separation of the Americas, the expansion of the early Atlantic, and the Cretaceous reorganization of North American river systems. The crown clades Atractosteus and Lepisosteus originated in the Cenozoic of eastern North America, implying that this region has served as both the origin of extant gar diversity and the refugium of this iconic ancient lineage. These results exemplify how combining phylogenomics with the fossil record provides congruence around the evolutionary history of ancient clades like gars and can reveal long-lost biogeographic patterns. [Lepisosteidae; fossilized birth death; biogeography; phylogenomics; paleontology.] [ABSTRACT FROM AUTHOR]

The Cretaceous-Paleogene (K-Pg) mass extinction was geologically instantaneous, causing the most drastic extinction rates in Earth's History. The rapid species losses and environmental destruction from the Chicxulub impact at 66.02 Ma made the K-Pg the most comparable past event to today's projected "sixth" mass extinction. The extinction famously eliminated major clades of animals and plankton. However, for land plants, losses primarily occurred among species observed in regional studies but left no global trace at the family or major-clade level, leading to questions about whether there was a significant K-Pg plant extinction. We review emerging paleobotanical data from the Americas and argue that the evidence strongly favors profound (generally >50%), geographically heterogeneous species losses and recovery consistent with mass extinction. The heterogeneity appears to reflect several factors, including distance from the impact site and marine and latitudinal buffering of the impact winter. The ensuing transformations have affected all land life, including true angiosperm dominance in the world's forests, the birth of the hyperdiverse Neotropical rainforest biome, and evolutionary radiations leading to many crown angiosperm clades. Although the worst outcomes are still preventable, the sixth mass extinction could mirror the K-Pg event by eliminating comparable numbers of plant species in a geologic instant, impoverishing and eventually transforming terrestrial ecosystems while having little effect on global plant-family diversity. [ABSTRACT FROM AUTHOR]

The lower Goodlands Member of the Turtle Mountain Formation is exposed in a streambank outcrop on the western flank of Turtle Mountain, south-western Manitoba, Canada (49°0′2″N, 100°14′51″W). This outcrop was sampled for a 1.5 m section of microfossil-rich non-marine clay and coal-rich sediments deposited in a coastal plain environment during the early Palaeocene. These sediments were deposited 65.4–65 Ma and thus offer an opportunity to reconstruct terrestrial palaeoecology 0.6 to 1 Ma after the Cretaceous–Paleogene boundary (K–Pg) extinction event. We use quantitative palynology to reconstruct terrestrial plant ecology and explore ecological patterns of recovery and succession of these communities on a millennial time scale. Quantitative palynological analyses shows that at the time of deposition of the Goodlands Member the landscape on the coastal plain of the Western Interior Seaway – in what is now south-western Manitoba – was covered in a forested canopied swamp with tall standing swamp cypress and other conifers, Juglandaceae (walnut family), birch, alder, elms and other angiosperms, with an understory of ferns and ground cover of Sphagnum moss. Notably, palms were present but scarce, indicating a relatively warm climate. No successional pattern of diversity and community composition is evident in the samples; all samples showed high plant diversity (33–54 taxa/sample, H′ 2–3). Vegetation in Manitoba recovered within 0.6 to 1 Ma following the K–Pg extinction event or was predominantly influenced by local environmental patterns independent of time. [ABSTRACT FROM AUTHOR]

Northern Hemisphere forests changed drastically in the early Eocene with the diversification of the oak family (Fagaceae). Cooling climates over the next 20 million years fostered the spread of temperate biomes that became increasingly dominated by oaks and their chestnut relatives. Here we use phylogenomic analyses of nuclear and plastid genomes to investigate the timing and pattern of major macroevolutionary events and ancient genome-wide signatures of hybridization across Fagaceae. Innovation related to seed dispersal is implicated in triggering waves of continental radiations beginning with the rapid diversification of major lineages and resulting in unparalleled transformation of forest dynamics within 15 million years following the K-Pg extinction. We detect introgression at multiple time scales, including ancient events predating the origination of genus-level diversity. As oak lineages moved into newly available temperate habitats in the early Miocene, secondary contact between previously isolated species occurred. This resulted in adaptive introgression, which may have further amplified the diversification of white oaks across Eurasia. Fagaceae are diverse family including trees of ecological and economic importance. This phylogenomic analysis of nuclear and plastid genomes reconstructs evolutionary history and finds evidence of multiple adaptive introgression events in this important plant family. [ABSTRACT FROM AUTHOR]

The global heterogeneity in export productivity after the Cretaceous‐Paleogene (K‐Pg) mass extinction is well documented, with some sites showing no change on geologic timescales, some demonstrating sustained decline, and a few showing a somewhat surprising increase. However, observational data come from sites so widespread that a key outstanding question is the geographic scale of changes in export productivity, and whether similar environments (e.g., open ocean gyres) responded similarly or whether heterogeneity is unrelated to environment. To address this, we developed three new Ba/Ti export productivity records from sites in the Gulf of Mexico and Caribbean which, combined with published data from a fourth site in the Chicxulub Crater itself, allow us to reconstruct regional changes in post K‐Pg export productivity for the first time. We find that, on a regional scale, export productivity change was homogenous, with all four sites showing a ∼300 Kyr period of elevated export production just after the boundary, followed by a longer period of decline. Interestingly, this interval of elevated export production appears to coincide with the post K‐Pg global micrite layer, which is thought to at least partially have been produced by blooms of carbonate‐producing cyanobacteria and other picophytoplankton. Global comparison of sites shows that elevated export productivity appears to have been most common in oligotrophic gyres, which suggests that changing plankton ecology evidenced by the micrite layer altered the biological pump, leading to a temporary increase in export production in these settings. Plain Language Summary: Primary producers are the base of the food chain; this group was severely damaged by the environmental effects associated with the Cretaceous‐Paleogene mass extinction. Determining how primary production recovered after this calamity is an important foundation for understanding how ecosystems recovered. Most previous work has focused on a process called export production, whereby organic carbon produced by phytoplankton is transferred to the ocean interior (some of which sinks to the seafloor and is buried). This work has shown that although most parts of the ocean recorded a decline in export production after the extinction event, some regions actually showed an increase. However, it was not clear on what geographic scale these differences occurred, or what caused them. We generated three new records of export production from a single region, the Gulf of Mexico/Caribbean Sea, and found a consistent increase in export production at each site for the same period of time after the extinction event. Comparison with other sites with increased export production shows that many are from open ocean gyres, suggesting that these regions were predisposed to increased export production in the earliest Paleocene because they were characterized by low productivity prior to the extinction. Key Points: Post K‐Pg export productivity was elevated across the Caribbean‐Gulf of Mexico region for ∼300 KyrAt sites with a clearly defined micrite layer, the end of micrite deposition coincides with the top of the highest productivity intervalElevated post K‐Pg export productivity appears to be a feature of oligotrophic low latitude open ocean sites [ABSTRACT FROM AUTHOR]

This contribution describes new species, genera and a subfamily (Anticytherideinae) of ostracods from the Upper Cretaceous (mid-late Campanian-Maastrichtian) marine deposits of the eastern flank of the Mississippi Embayment. New taxa assigned to the subfamily include Anticythereis dorsennus and A. slipperi; the new genus Asculdoracythereis, which includes the new species As. asculdora, As. invicta, and As. pseudoalabamensis; the new genus Frodocythereis, which includes the new species F. frodoi; the new genus Laevipellacythereis, which includes the new species L. colossus and L. laevipellis; and the new genus Tumulocythereis, which includes the new species T. incompta, T. tiberti, and T. tumulus. Previously described species assigned to the genus Anticythereis are re-evaluated, some of which are assigned to one of the new genera. Synapomorphic characters of the new subfamily include a combination of pronounced external post-ocular sulcus with corresponding pair of internal, rimmed inverted platforms and a distinctive "yin-yang" adductor muscle scar pattern. The taxa display remarkably rapid evolution. The earliest species (Anticythereis sp. 1) occurs in the planktonic foraminiferal Radotruncana calcarata Taxon Range Zone of mid- to late Campanian age and by the end of the Maastrichtian there are more than 20 species. Most species have very localized occurrences, including several that occur only at a single outcrop. Although species are found on the eastern flank of the Mississippi Embayment and the Atlantic Coastal Plain, none have been observed on the western flank of the Mississippi Embayment. Species have been assigned to the genus Anticythereis from other continents (South America, Europe and Africa), but those taxa lack distinctive features of the Anticytherideinae, which is endemic to North America. The group became extinct at the Cretaceous-Paleogene boundary. [ABSTRACT FROM AUTHOR]

As one of the most successful group of organisms, mammals occupy a variety of niches on Earth as a result of macroevolution. Transcription factors (TFs), the fundamental regulators of gene expression, may also have evolved. To examine the relationship between TFs and mammalian macroevolution, we analyzed 140,821 de novo-identified TFs and their birth and death histories from 96 mammalian species. Gene tree vs. species tree reconciliation revealed that placental mammals experienced an upsurge in TF losses around 100 million years ago (Mya) and also near the Cretaceous–Paleogene boundary (K–Pg boundary, 66 Mya). Early Euarchontoglires, Laurasiatheria and marsupials appeared between 100 and 95 Mya and underwent initial diversification. The K-Pg boundary was associated with the massive extinction of dinosaurs, which lead to adaptive radiation of mammals. Surprisingly, TF loss decelerated, rather than accelerated, molecular evolutionary rates of their target genes. As the rate of molecular evolution is affected by the mutation rate, the proportion of neutral mutations and the population size, the decrease in molecular evolution may reflect increased functional constraints to survive target genes. [ABSTRACT FROM AUTHOR]

Partially carbonized driftwood recovered from a lag deposit at the Arkadelphia Formation–Midway Group Contact (K–Pg) near Malvern, Arkansas contains an abundance of macrobioerosion. Macroborings are oriented perpendicular and oblique to the wood grain, straight to sinuous in shape, ≤8 cm long, may have calcitic linings, and belong to Teredolites clavatus (Kelly & Bromley, 1984). The abundance and tightly spaced position of borings on all driftwood surfaces suggests the wood was afloat and/or exposed on or near the seafloor in a shallow marine setting for an extended period of time before becoming buried. Transverse, radial, and tangential thin section analysis of the driftwood identifies distinct growth rings, tracheid and ray cells, ray pits, and resin canals of the bald cypress genus, Taxodium. The presence of Taxodium wood in addition to a diverse and abundant assemblage of transitional to shallow marine vertebrates in the Gulf Coastal Plain of southwestern Arkansas indicate that brackish water swamps were in proximity to the ancestral shoreline around the K–Pg boundary and that these remains were concentrated into a lag deposit as the result of storm events, sea-level cyclicity, and possibly impact generated tsunamis. [ABSTRACT FROM AUTHOR]

We report K–Pg-age deposits in Baja California, Mexico, consisting of terrestrial and shallow-marine materials re-sedimented onto the continental slope, including corals, gastropods, bivalves, shocked quartz grains, an andesitic tuff with a SHRIMP U–Pb age (66.12 ± 0.65 Ma) indistinguishable from that of the K–Pg boundary, and charred tree trunks. The overlying mudstones show an iridium anomaly and fungal and fern spores spikes. We interpret these heterogeneous deposits as a direct result of the Chicxulub impact and a mega-tsunami in response to seismically-induced landsliding. The tsunami backwash carried the megaflora offshore in high-density flows, remobilizing shallow-marine fauna and sediment en route. Charring of the trees at temperatures up to > 1000 °C took place in the interval between impact and arrival of the tsunami, which on the basis of seismic velocities and historic analogues amounted to only tens of minutes at most. This constrains the timing and causes of fires and the minimum distance from the impact site over which fires may be ignited. [ABSTRACT FROM AUTHOR]

The genus Surangea Chitaley et Sheikh, based on permineralized specimens from the Deccan Intertrappean Beds of central India, was originally considered to represent a fern megasporangium. Reexamination of original material and new specimens has revealed that the structures are capsular fruits with well-defined seeds, rather than megasporangia. We describe Surangea fruits in detail, based on peels and micro-CT scanning, and document its distribution among multiple localities of the Deccan Intertrappean Beds. The fruits are pentacarpellate septicidal capsules with ~8-12 seeds per locule. The seeds are prominently ornamented with parallel ridges and have a curved embryo/endosperm cavity and a prominent aril. This set of features indicates eudicotyledonous affinities for Surangea. In particular, the combination of septicidal capsules, axile placentation and arillate campylotropus seeds suggests affinity with the order Myrtales, but it does not fit cleanly within an extant family. Surangea fruits add to the diversity of angiosperms known from this late Maastrichtian flora. It joins several other fruit types known from the Deccan flora that do not fall neatly into extant families, possibly representing parts of an endemic community that succumbed to environmental stress associated K-Pg boundary events and/or subsequent northward rafting of the Indian subcontinent. [ABSTRACT FROM AUTHOR]

Retroelement insertions (RIs) are low-homoplasy characters that are ideal data for addressing deep evolutionary radiations, where gene tree reconstruction errors can severely hinder phylogenetic inference with DNA and protein sequence data. Phylogenomic studies of Neoaves, a large clade of birds (>9000 species) that first diversified near the Cretaceous–Paleogene boundary, have yielded an array of robustly supported, contradictory relationships among deep lineages. Here, we reanalyzed a large RI matrix for birds using recently proposed quartet-based coalescent methods that enable inference of large species trees including branch lengths in coalescent units, clade-support, statistical tests for gene flow, and combined analysis with DNA-sequence-based gene trees. Genome-scale coalescent analyses revealed extremely short branches at the base of Neoaves, meager branch support, and limited congruence with previous work at the most challenging nodes. Despite widespread topological conflicts with DNA-sequence-based trees, combined analyses of RIs with thousands of gene trees show emergent support for multiple higher-level clades (Columbea, Passerea, Columbimorphae, Otidimorphae, Phaethoquornithes). RIs express asymmetrical support for deep relationships within the subclade Afroaves that hints at ancient gene flow involving the owl lineage (Strigiformes). Because DNA-sequence data are challenged by gene tree-reconstruction error, analysis of RIs represents one approach for improving gene tree-based methods when divergences are deep, internodes are short, terminal branches are long, and introgressive hybridization further confounds species–tree inference. [ABSTRACT FROM AUTHOR]