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There is a strong relationship between metazoan body size and extinction risk. However, the size selectivity and underlying mechanisms in foraminifera, a common marine protozoa, remain controversial. Here, we found that foraminifera exhibit size-dependent extinction selectivity, favoring larger groups (>7.4 log10 cubic micrometer) over smaller ones. Foraminifera showed significant size selectivity in the Guadalupian-Lopingian, Permian-Triassic, and Cretaceous-Paleogene extinctions where the proportion of large genera exceeded 50%. Conversely, in extinctions where the proportion of large genera was

Fossils of large animals have long influenced social practices and ideologies in human societies, including the fantastic myths of giants, heroes, and gods in ancient Greece. It has been estimated that purposeful fossil collecting in Greece began in the Late Bronze Age. However, previous archaeological finds of fossils from mainland Greece were not well documented in secure contexts that dated this far back in time. Herein, we present a newly recognized fossilized astragalus bone recently found in the legacy collections of the archaeological site of Mycenae. It was originally recovered by excavations in the 1970s and recently reanalyzed at the Mycenae Museum. Our analysis explored the available evidence of the find location, the state of fossil preservation, and the species represented. The results suggest that a fossilized rhinoceros (Stephanorhinus) astragalus was collected in the past, possibly from afar. Evidence indicates it was brought to Mycenae, where it was deposited near an interesting array of artifacts in a basement storage area of the Southwest Quarter, sometime in the thirteenth century BCE. This find represents the earliest secure evidence of large animal fossil use by people in mainland Greece, dating to the Late Bronze Age.

The jaguar (Panthera onca) is the largest living cat species native to the Americas and one of few large American carnivorans to have survived into the Holocene. However, the extent to which jaguar diversity declined during the end-Pleistocene extinction event remains unclear. For example, Pleistocene jaguar fossils from North America are notably larger than the average extant jaguar, leading to hypotheses that jaguars from this continent represent a now-extinct subspecies (Panthera onca augusta) or species (Panthera augusta). Here, we used a hybridization capture approach to recover an ancient mitochondrial genome from a large, late Pleistocene jaguar from Kingston Saltpeter Cave, Georgia, United States, which we sequenced to 26-fold coverage. We then estimated the evolutionary relationship between the ancient jaguar mitogenome and those from other extinct and living large felids, including multiple jaguars sampled across the species' current range. The ancient mitogenome falls within the diversity of living jaguars. All sampled jaguar mitogenomes share a common mitochondrial ancestor ~400 thousand years ago, indicating that the lineage represented by the ancient specimen dispersed into North America from the south at least once during the late Pleistocene. While genomic data from additional and older specimens will continue to improve understanding of Pleistocene jaguar diversity in the Americas, our results suggest that this specimen falls within the variation of extant jaguars despite the relatively larger size and geographic location and does not represent a distinct taxon.

The Santa Barbara Basin is an extraordinary archive of environmental and ecological change, where varved sediments preserve microfossils that provide an annual to decadal record of the dynamics of surrounding ecosystems. Of the microfossils preserved in these sediments, benthic foraminifera are the most abundant seafloor-dwelling organisms. While they have been extensively utilized for geochemical and paleoceanographic work, studies of their morphology are lacking. Here we use a high-throughput imaging method (AutoMorph) designed to extract 2D data from photographic images of fossils to produce a large image and 2D shape dataset of recent benthic foraminifera from two core records sampled from the center of the Santa Barbara Basin that span an ~800-year-long interval during the Common Era (1249-2008 CE). Information on more than 36,000 objects is included, of which more than 22,000 are complete or partially-damaged benthic foraminifera. The dataset also includes other biogenic microfossils including ostracods, pteropods, diatoms, radiolarians, fish teeth, and shark dermal denticles. We describe our sample preparation, imaging, and identification techniques, and outline potential data uses.

The phenomenon of lithic miniaturization during the Late Pleistocene at times coincided with increased artifact standardization and cutting edge efficiency-likely reflecting the use of small, sharp artifacts as interchangeable inserts for composite cutting tools and hunting weapons. During Marine Isotope Stage 2, Upper Paleolithic toolmakers in northern East Asia specifically used pressure techniques to make small, highly standardized lithic artifacts called microblades. However, little is currently known about how microblades affected the cutting edge efficiency of the toolkits they were a part of. We applied three methods of analyzing cutting edge efficiency to two Upper Paleolithic assemblages recently excavated from Tolbor-17, Mongolia, that document the periods before and after the introduction of microblade technology to the Tolbor Valley. A model incorporating allometric relationships between blank cutting edge length and mass suggests no difference in efficiency between the two periods, while two more conventional approaches both indicate a significant increase. The potential for improved cutting edge efficiency is only observed when the microblade sample is artificially inflated via simulation. Our results highlight challenges related to detecting and interpreting archaeological differences in cutting edge efficiency at the assemblage level.

Ontocetus is one of the most notable extinct odobenines owing to its global distribution in the Northern Hemisphere. Originating in the Late Miocene of the western North Pacific, this lineage quickly spread to the Atlantic Ocean during the Pliocene, with notable occurrences in England, Belgium, The Netherlands, Morocco and the eastern seaboard of the United States. Reassessment of a pair of mandibles from the Lower Pleistocene of Norwich (United Kingdom) and a mandible from the Upper Pliocene of Antwerp (Belgium) that were referred to as Ontocetus emmonsi reveals existences of features of both Ontocetus and Odobenus. The presence of four post-canine teeth, a lower canine larger than the cheek-teeth and a lower incisor confirms the assignment to Ontocetus; simultaneously, characteristics such as a fused and short mandibular symphysis, a well-curved mandibular arch and thin septa between teeth align with traits usually found in Odobenus. Based on a combination of these characters, we describe Ontocetus posti, sp. nov. Its mandibular anatomy suggests, a better adaptation to suction-feeding than what was previously described in the genus suggesting that Ontocetus posti sp. nov. likely occupied a similar ecological niche to the extant walrus Odobenus rosmarus. Originating from the North Pacific Ocean, Ontocetus most likely dispersed via the Central American Seaway. Although initially discovered in the Lower Pliocene deposits of the western North Atlantic, Ontocetus also left its imprint in the North Sea basin and Moroccan Plio-Pleistocene deposits. The closure of the Isthmus of Panama during the Mio-Pliocene boundary significantly impacted the contemporary climate, inducing global cooling. This event constrained Ontocetus posti in the North Sea basin leaving the taxon unable to endure the abrupt climate changes of the Early Pleistocene, ultimately going extinct before the arrival of the extant counterpart, Odobenus rosmarus.

Placerias hesternus, a Late Triassic dicynodont, is one of the last megafaunal synapsids of the Mesozoic. The species has a tusk-like projection on its maxillary bone, known as the caniniform process. This process has been hypothesized to be sexually dimorphic since the 1950s, however this claim has not been thoroughly investigated quantitatively. Here, we examined maxillae, premaxillae, quadrates, and fibulae from a single population from the Placerias Quarry in the Blue Mesa Member of the Chinle Formation, near St. Johns, Arizona, USA to determine if the caniniform process is dimorphic. We made a total of 25 measurements from the four bones and used a maximum likelihood framework to compare the fit of unimodal versus bimodal distributions for each set of measurements. Our results from complete maxillae reveal that the caniniform process has two distinct morphs, with a shorter and longer form. This interpretation is substantiated both by strong statistical support for bimodal distribution of caniniform lengths, and by clustering analysis that clearly distinguishes two morphs for the maxillae. Clustering analysis also shows support for potential dimorphism in the shape of the quadrate. However, no measurements from elements other than the maxilla have a strong likelihood of bimodal distribution. These results support the long-standing hypothesis that the caniniform in Placerias was dimorphic. Alternative explanations to sexual dimorphism that could account for the dimorphism among these fossils include the presence of juveniles in the sample or time-averaged sampling of a chronospecies, but both have been previously rejected for the Placerias Quarry population. The lack of strong dimorphism in non-maxilla elements and increased variation in caniniform length of the large-caniniform morph suggest that the caniniform is a secondary sexual trait, possibly used in intraspecific competition.

Extremes in organismal size have broad interest in ecology and evolution because organismal size dictates many traits of an organisms biology. There is particular fascination with identifying upper size extremes in the largest vertebrates, given the challenges and difficulties of measuring extant and extinct candidates for the largest animal of all time, such as whales, terrestrial non-avian dinosaurs, and extinct marine reptiles. The discovery of Perucetus colossus, a giant basilosaurid whale from the Eocene of Peru, challenged many assumptions about organismal extremes based on reconstructions of its body weight that exceeded reported values for blue whales (Balaenoptera musculus). Here we present an examination of a series of factors and methodological approaches to assess reconstructing body weight in Perucetus, including: data sources from large extant cetaceans; fitting published body mass estimates to body outlines; testing the assumption of isometry between skeletal and body masses, even with extrapolation; examining the role of pachyostosis in body mass reconstructions; addressing method-dependent error rates; and comparing Perucetus with known physiological and ecological limits for living whales, and Eocene oceanic productivity. We conclude that Perucetus did not exceed the body mass of todays blue whales. Depending on assumptions and methods, we estimate that Perucetus weighed 60-70 tons assuming a length 17 m. We calculated larger estimates potentially as much as 98-114 tons at 20 m in length, which is far less than the direct records of blue whale weights, or the 270 ton estimates that we calculated for body weights of the largest blue whales measured by length.

The diversity of vertebrate skeletons is often attributed to adaptations to distinct ecological factors such as diet, locomotion, and sensory environment. Although the adaptive evolution of skull, appendicular skeleton, and vertebral column is well studied in vertebrates, comprehensive investigations of all skeletal components simultaneously are rarely performed. Consequently, we know little of how modes of evolution differ among skeletal components. Here, we tested if ecological and phylogenetic effects led to distinct modes of evolution among the cranial, appendicular and vertebral regions in extant carnivoran skeletons. Using multivariate evolutionary models, we found mosaic evolution in which only the mandible, hindlimb and posterior (i.e. last thoracic and lumbar) vertebrae showed evidence of adaptation towards ecological regimes whereas the remaining skeletal components reflect clade-specific evolutionary shifts. We hypothesize that the decoupled evolution of individual skeletal components may have led to the origination of distinct adaptive zones and morphologies among extant carnivoran families that reflect phylogenetic hierarchies. Overall, our work highlights the importance of examining multiple skeletal components simultaneously in ecomorphological analyses. Ongoing work integrating the fossil and palaeoenvironmental record will further clarify deep-time drivers that govern the carnivoran diversity we see today and reveal the complexity of evolutionary processes in multicomponent systems.

Aim: Given the rapid pace of climate change and its significant impact on species distribution and survival, understanding the dynamics of ecological niches over time becomes imperative. By employing ecological niche models and species distribution models, alongside analyses of historical occurrence records and palaeoclimatic data, we aimed to assess the extent of changes in the niche of Porites astreoides from the Holocene to the present. Specifically, we quantified the amount of: (1) niche stability, (2) niche expansion, (3) niche decline and (4) niche overlap in both the environmental and geographical space. Location: Atlantic Ocean. Taxon: Cnidarian, Scleractinia. Materials and Methods: Through fossil and current records and environmental variables from the same periods, we use two ecological niche modelling approaches (overlap and maximum entropy) to analyse niche dynamics in environmental and geographical space, specifically the degree of expansion, stability and loss of niches over the last ~8000 years. We used a principal component analysis to build the models within two different calibration areas (minimum convex polygon and buffer). Results: Our results were similar, except for the loss of habitat, across the calibration areas used to build the models. The PCA used to build the models accounts for more than 65% of the variation in the data. Most of the environmental niche remained stable with an increase of almost a third and a negligible loss. Models in geographical space showed that most of the suitable area remained stable, but the species expanded its range from the Caribbean to the coast of Brazil. The analysis also showed a high value of niche overlap in environmental and geographical spaces. Main Conclusions: The species studied is one of the corals with the greatest capacity to adapt to new environments and locations, but it also has a high tendency to preserve niche traits. These characteristics helped the species to expand its environmental and geographical niche in a period of relative climatic stability. On the other hand, these same characteristics of niche conservatism can lead the species to population decline and habitat loss, if the speed of adaptation is lower than the rapid climate changes predicted for the middle and end of the 21st century. [ABSTRACT FROM AUTHOR]

The family Bovidae [Mammalia: Artiodactyla] is speciose and has extant representatives on every continent, forming key components of mammal communities. For these reasons, bovids are ideal candidates for studies of ecomorphology. In particular, the morphology of the bovid humerus has been identified as highly related to functional variables such as body mass and habitat. This study investigates the functional morphology of the bovid distal humerus in isolation due to its increased likelihood of preservation in the fossil record, and the resulting opportunity for a better understanding of the ecomorphology of extinct bovids. A landmark scheme of 30 landmarks was used to capture the 3D distal humerus morphology in 111 extant bovid specimens. We find that the distal humerus has identifiable morphologies associated with body mass, habitat preference and tribe affiliation and that some characteristics are shared between high body mass bovids and those living on hard, flat terrain which is likely due to the high stress on the bone in both cases. We directly apply our findings regarding extant bovids to the extinct alcelaphine bovid, Rusingoryx atopocranion from the mid to late Pleistocene (>33–45 ka) Lake Victoria region of Kenya. This species is known for some peculiar morphologies including a domed cranium with hollow nasal crests, and having small hooves for a bovid of its size. Another interesting aspect of Rusingoryx's skeletal morphology which has not been addressed is an unusual protrusion on the lateral epicondyle of the distal humerus. Despite considerable individual variation in the Rusingoryx specimens, we find evidence to support its historical assignment to the tribe Alcelaphini, and that it likely preferred open grassland habitats, which is consistent with independent reconstructions of the palaeoenvironment. We also provide the most accurate body mass estimate for Rusingoryx to date, based on distal humerus centroid size. Overall, we are able to conclude that the distal humerus in extant bovids is highly informative regarding body mass, habitat preference and tribe, and that this can be applied directly to a fossil taxon with promising results. [ABSTRACT FROM AUTHOR]

Mawsonia constitutes one of the most conspicuous fossil coelacanth taxa, due to its unique anatomy and possible maximum body size. It typifies Mesozoic coelacanth morphology, before the putative disappearance of the group in the fossil record. In this work, the three‐dimensional cranial anatomy and body size estimations of this genus are re‐evaluated from a recently described specimen from Upper Jurassic deposits of Uruguay. The 3D restoration was performed directly on the material based on anatomical information provided by the living coelacanth Latimeria and previous two‐dimensional restorations of the head of Mawsonia. The montage was then scanned with computed tomography and virtually adjusted to generate an interactive online resource for future anatomical, taxonomic and biomechanical research. In general terms, the model constitutes a tool to improve both the anatomical knowledge of this genus and its comparison with other coelacanths. It also facilitates the evaluation of possible evolutionary trends and the discussion of particular features with potential palaeobiological implications, such as the anterior position of the eye and the development of the pseudomaxillary fold. Regarding the body size, a previous model for body size estimation based on the gular plate was submitted to OLS, RMA, segmented linear and PGLS regressions (including the evaluation of regression statistics, variance analysis, t‐tests and residual analysis). The results point to a power relationship between gular and total lengths showing a better support than a simple linear relationship. The new resulting equations were applied to the studied individual and are provided for future estimates. Although an isometric evolutionary growth cannot be rejected with the available evidence, additional models developed with other bones will be necessary to evaluate possible hidden evolutionary allometric trends in this group of fishes, thus avoiding overestimates. [ABSTRACT FROM AUTHOR]

Derived ornithopods, such as hadrosaurids, show a high occurrence of fossilized lesions and diseases. However, paleopathologies in iguanodontians seem to be less common, considering the rich fossil record of these taxa in Europe, in particular in Belgium, Britain and Spain. Here, we describe an iguanodontian femur discovered in England that exhibits a large overgrowth of its lateral aspect, not previously recognized in any other similar remains. The specimen was scanned with micro‐computed tomography (microCT) and later sectioned in three sites of the overgrowth for histological analysis. The femur belongs to an early adult Iguanodontia indet., based on the presence of a woven parallel fibered complex in the outer cortex and three to four lines of arrested growth. Internal analysis of the dome‐like overgrowth suggests it can be diagnosed as a fracture callus. The injury might have negatively impacted upon the animal's locomotion as the trauma had occurred in the region above the knee, a crucial spot for hindlimb musculature. Finally, a cancellous medullary bone‐like tissue was recognized in the medullary cavity next to the pathological overgrowth. An attempt was made to determine the precise nature of this tissue, as medullary bone is linked with the ovulation period in (avian) dinosaurs, whereas other types of endosteal, medullary bone‐like tissue have previously been recognized in pathological bones. [ABSTRACT FROM AUTHOR]

The Pleurotomarioidea, commonly referred to as slit shells, constitute one of the most ancient and enduring lineages within the phylum Mollusca, with its fossil record tracing back to the Upper Cambrian epoch. Its rareness and evolutionary antiquity surpass even that of the nautilus. In this study, we conducted the first transcriptome sequencing and analyses of Entemnotrochus rumphii (Schepman, 1879), a representative species of Pleurotomarioidea. Full-length transcriptome sequencing of E. rumphii was performed using the PacBio Sequel II platform with SMRT technology. A total of 64.38 gigabytes of data and 964,550 polymerase reads were generated, resulting in 28,068,998 subreads after data filtering. After de-duplication, correction, and clustering, we identified 19,273 genes. Additionally, next-generation sequencing was performed on 11 tissues of E. rumphii. This investigation provides a detailed portrayal and analytical scrutiny of its transcriptomic landscape. [ABSTRACT FROM AUTHOR]

The Triassic represents a critical period for understanding the turnover of insect fauna from the Paleozoic to the Mesozoic following the end-Permian mass extinctions (EPME); however, fossil deposits from the Early-Middle Triassic are scarce. The exceptionally preserved 239 million-year-old fossil insect fauna recorded at Monte San Giorgio (Switzerland), including 248 fossils representing 15 major insect clades is presented here. Besides the exceptional features, including their small size and excellent preservation, the fossils have importance in the evolutionary history of the group. The taxonomic and ecological diversity recovered, including both freshwater (dragonflies and caddisflies) and terrestrial taxa (true bugs and wasps), demonstrates that complex environments sustained a paleocommunity dominated by monurans (thought not to have survived the EPME), midges, and beetles. Interestingly, a blattodean-like fossil bearing an external ootheca was also found, important for understanding Paleozoic roachoids to extant cockroaches' transition and the evolution of maternal brood care. Moreover, the youngest and first complete specimen of †Permithonidae and the oldest sawfly fossils were discovered. Finally, round-shaped bodies, compatible with seminal capsules or lycophyte spores, were found on the abdomens of several midge-like individuals. If these are spores, non-seed-bearing plants could have been the first entomophilous plants rather than gymnosperms, as recently supposed. Altogether, these fossils contribute substantially to understanding insect evolution and Paleozoic-Mesozoic faunal turnover. The exceptionally preserved 239 million-year-old fossil insect fauna discovered at Monte San Giorgio includes 248 fossils from 15 major insect clades, contributing significantly to the understanding of insect evolution. [ABSTRACT FROM AUTHOR]

A new sphenophyllalean strobilus, Bussacoconus zeliapereirae gen. et sp. nov. is described from the Vale da Mó Formation (Stephanian C, Upper Pennsylvanian) of the Buçaco Carboniferous Basin, central western Portugal. Bussacoconus zeliapereirae is diagnosed based on macromorphological features, which distinguish it from the other late Palaeozoic sphenophyllalean cones for by its remarkably distinctive branched sporangiophores and ribs. The primary sporangiophores are characterised by being developed, strong and rigid, and distally hook-shaped, displaying thin secondary sporangiophores, which individually bearing a single sporangium at the end. In addition, Bussacoconus zeliapereirae is also taxonomically distinct from its distal and basally hook-shaped strong ribs. Such singular features represent evolutionary macromorphological novelties (autapomorphies) into the Sphenophyllales. As a result, this fossil finding provides new information on the functional and ecological morphology of the sphenophyllalean strobili. [ABSTRACT FROM AUTHOR]

Burrowed discontinuity surfaces associated with condensed fossil concentrations demarcate breaks (hiatuses) in the Phanerozoic marine sedimentary record. Such intervals may be difficult to interpret in view of complex anatomy and varied fossil signatures. Transformation of a discontinuity surface into a heavily burrowed 'pseudobreccia' may further complicate the record, but this issue has remained unexploited to date. The richly fossiliferous Cretaceous–Paleogene (Maastrichtian–Danian) boundary interval exposed in Poland provides opportunities to test the influence of burrow-generated pseudobreccia on the preservation of associated hiatal fossil concentrations. Here, we document pseudobreccia anatomy and fossil-sediment relationships by three-dimensional X-ray computed tomography imaging. In the pseudobreccia zone, we identify a distinctive assemblage of late Maastrichtian fossils, which underwent subsurface preparation by burrowers in a hitherto unreported ichno-taphonomic process. Recognition of pseudobreccia is a prerequisite for the interpretation of the stratigraphy, sedimentology and fossil record of such intervals, which is of special interest for periods of major biotic turnovers, like the end-Cretaceous mass extinction. [ABSTRACT FROM AUTHOR]

Fossil identification practices have a profound effect on our interpretation of the past because these identifications form the basis for downstream analyses. Therefore, well-supported fossil identifications are necessary for examining the impact of past environmental changes on populations and communities. Here we apply an apomorphic identification framework in a case study identifying fossil lizard remains from Hall's Cave, a late Quaternary fossil site located in Central Texas, USA. We present images and descriptions of a broad comparative sample of North American lizard cranial elements and compile new and previously reported apomorphic characters for identifying fossil lizards. Our fossil identifications from Hall's Cave resulted in a minimum of 11 lizard taxa, including five lizard taxa previously unknown from the site. Most of the identified fossil lizard taxa inhabit the area around Hall's Cave today, but we reinforce the presence of an extirpated species complex of horned lizard. A main goal of this work is to establish a procedure for making well-supported fossil lizard identifications across North America. The data from this study will assist researchers endeavoring to identify fossil lizards, increasing the potential for novel discoveries related to North American lizards and facilitating more holistic views of ancient faunal assemblages. [ABSTRACT FROM AUTHOR]

The Early Cretaceous Jehol Biota in northeastern China has yielded a diversity of feathered dromaeosaurid dinosaurs and expanded our knowledge of avian origin and flight evolution. However, histology-based ontogenetic references and detailed morphological studies remain limited relative to the abundant fossils. Here, a new specimen of microraptorine from the Lower Cretaceous Jiufotang Formation is described. This specimen includes a nearly complete postcranial skeleton and inferred as a Microraptor based on revised osteological characters. The femoral length of the new specimen is less than 5 cm, making it the smallest dromaeosaurid individual reported from the Jehol Biota until now. Osteohistological analysis reveals that this individual was a juvenile that is less than one-year old. The new specimen provides additional morphological details that are poorly preserved in the other Microraptor specimens, including aspects of the coracoid, ilium, and tail. Additionally, the sacrals and pubic symphysis of the new specimen have respectively fused at the juvenile stage. This phenomenon suggests caution should be taken in using skeletal fusion for assessing the ontogenetic stage of Microraptor specimens, highlighting the importance of histological analysis. [ABSTRACT FROM AUTHOR]

Van Valen's law of constant extinction postulates that in comparable ecological contexts, the probability for a taxon to survive to the next time interval is independent of how long it has already existed. The law implies that species do not age, that is, the survival probability from one time step to the next does not decrease with species' age. While the original law describes survivorship over time, here we show that there is a counterpart to the law describing species dynamics in space. Indeed, the probability for a taxon to expand a step further in its range size does not depend on how large of a range the taxon already occupies. We show that such patterns of stochastically constant expansion are common in the global mammalian fossil record throughout the Cenozoic and are consistent with the mammalian species distribution in the present-day world. Intriguing is that the law in space holds best for the linear dimension of the range rather than for the range area. We interpret this as suggesting that species primarily expand via the frontier of their range; this process is known as leading-edge expansion in ecology. And while the difficulty of expanding in linear steps remains constant, the area gains diminish. In line with evolutionary theory collectively known as the Red Queen's hypothesis, this suggests that the effectiveness of expansion saturates, even if species longevity does not. When interpreted in reverse, this explains from the macroevolutionary perspective why larger species ranges are associated with lower extinction risks. [ABSTRACT FROM AUTHOR]

ABSTRACT Despite the valuable palaeoecological and palaeoenvironmental information provided by vertebrate tracks, those made in semi‐liquid sediments have been largely overlooked because they are assumed to be preserved as a mass of disrupted sediment and to have a low preservation potential. Nevertheless, understanding their mechanisms of formation, infilling and preservation is crucial since they could be more abundant in the fossil record than expected or be misinterpreted as other soft‐sediment deformation structures. To solve these aspects, this study analyses consecutive cross‐sections performed along a human track made by a shod foot in semi‐liquid sediments in the upper intertidal flats of the Bay of Mont‐Saint‐Michel (north‐west France) and monitored until its complete burial. These were compared with cross‐sections of tracks made in a flume tank. Cross‐sections reveal that the sediment structures associated with these tracks reflect the mechanism of their formation and infilling, and even the footstep dynamics. These structures comprise: (i) marginal rims that developed at both sides of tracks during foot penetration; (ii) upward deformation structures produced during foot withdrawal; (iii) a syn‐track infilling, which almost entirely fills the tracks during the withdrawal, formed by sediment collapsed from the track walls or by liquefied sediment; (iv) a post‐track infilling that fills the tracks completely during their subsequent flooding. This work demonstrates that these tracks have a high preservation potential in tidal settings, especially if they are made after the peak of a spring tide period, and undergo desiccation and consolidation during neap tides, which prevents their erosion and favours their burial by sediment. The identification of the above‐mentioned structures in fossil counterparts provides useful palaeoenvironmental information, because they allow discriminating these tracks from those made in sediments with less water content and from other soft‐sediment deformation structures (i.e. convolute bedding and balls‐and pillows) with which they share strong resemblances. [ABSTRACT FROM AUTHOR]

The understanding of the taxonomy, diversity, and evolutionary patterns of caviids in northwestern Argentina is still in the process of development. This paper presents new insights into the systematic and evolution of Orthomyctera andina (Rovereto, 1914), one of the most abundant species within Caviidae Fischer de Waldheim, 1817, in the fossil record of this region. A comprehensive anatomical description and taxonomic review of Orthomyctera andina in a phylogenetic context is provided. Moreover, it includes a redescription of the type specimen of Orthomyctera rigens (Ameghino, 1888). The taxonomical results confirm that O. andina belongs to a different genus: Orocavia (Kraglievich, 1932). The phylogenetic analysis further confirms the placement of both species within Caviinae Fischer de Waldheim, 1817. Orthomyctera andina is the sister taxon of the clade that includes Microcavia Gervais & Ameghino, 1880, Dolicavia Ameghino, 1916, Neocavia Kraglievich, 1932, and Orthomyctera Ameghino, 1889. It is supported by a combination of plesiomorphic characters (e.g. furrow opposite to hypoflexus/id in molariforms) shared with basal taxa and Dolichotinae Pocock, 1922 and derived characters (such as a terreced palate, external auditory meatus below the occlusal surface, length of p4-m1 shorter than length of m2-m3) shared with Caviinae. This study aims to elucidate the taxonomic status of these poorly known rodents and their relationships within Caviidae. Additionally, it incorporates a biogeographic analysis of caviomorph communities from the late Neogene in Argentina. [ABSTRACT FROM AUTHOR]

Araripesuchus is a genus of medium-sized (approximately 1 m long) terrestrial uruguaysuchid crocodyliforms that lived during the Cretaceous in Gondwana. There is limited information about juvenile notosuchian specimens due to the scarcity of well-preserved fossils from ontogenetic series. This study presents a comprehensive morphological description of three juvenile specimens of Araripesuchus (MPCA PV 259, 624, and 1193) from the La Buitrera Paleontological Area, Patagonia, Argentina. These early developmental-stage specimens were identified at a generic level due to the absence of mature anatomical characters for precise classification. Variations were observed between these juveniles and the previously examined adult specimens from the same region. As a result, a list of characters indicating ontogenetic variants was provided. These characters represent discrete traits that vary throughout the life of the individuals and could serve as ontogenetic indicators. This study offers a deeper understanding of the skeletal anatomy of Araripesuchus and its range of morphological variation, providing new data for the characterisation of the genus and potential new taxa of uruguaysuchids. [ABSTRACT FROM AUTHOR]

Tardigrades are a diverse phylum of microscopic invertebrates widely known for their extreme survival capabilities. Molecular clocks suggest that tardigrades diverged from other panarthropods before the Cambrian, but their fossil record is extremely sparse. Only the fossil tardigrades Milnesium swolenskyi (Late Cretaceous) and Paradoryphoribius chronocaribbeus (Miocene) have resolved taxonomic positions, restricting the availability of calibration points for estimating for the origin of this phylum. Here, we revise two crown-group tardigrades from Canadian Cretaceous-aged amber using confocal fluorescence microscopy, revealing critical morphological characters that resolve their taxonomic positions. Formal morphological redescription of Beorn leggi reveals that it features Hypsibius-type claws. We also describe Aerobius dactylus gen. et sp. nov. based on its unique combination of claw characters. Phylogenetic analyses indicate that Beo. leggi and Aer. dactylus belong to the eutardigrade superfamily Hypsibioidea, adding a critical fossil calibration point to investigate tardigrade origins. Our molecular clock estimates suggest an early Paleozoic diversification of crown-group Tardigrada and highlight the importance of Beo. leggi as a calibration point that directly impacts estimates of shallow nodes. Our results suggest that independent terrestrialization of eutardigrades and heterotardigrades occurred around the end-Carboniferous and Lower Jurassic, respectively. These estimates also provide minimum ages for convergent acquisition of cryptobiosis. The redescription of two Cretaceous-aged tardigrade fossils resolved their relationship with modern species, with one belonging to a new genus. This new information is critical for calibrating the timing of the evolutionary origins of tardigrades. [ABSTRACT FROM AUTHOR]

The Tuchengzi Formation represents a Jurassic – Cretaceous boundary regional lithological unit that bridges the temporal gap between the Yanliao biota and the Jehol biota. Tetrapod tracks represent the most significant vertebrate fossil records in the formation, and can be employed to supplement the Late Jurassic fauna and palaeoecological data from northern China. Here, we present a re-analysis of the theropod tracks from the Luofenggou site in northern Hebei Province, utilising an additional 3D model and a locomotory analysis to provide further insights into the ecological context. A morphological analysis indicates that these tracks are more similar to Grallator than to the previously proposed Therangospodus. The latter is diagnosed by coalesced, elongate, oval digital pads lacking a separation in distinct phalangeal pads, whereas these are clearly defined in the presented Tuchengzi material. They can therefore be assigned to the widespread G. ssatoi ichnospecies from the Tuchengzi Formation, although they are longer and more variable in size than other G. ssatoi. A general consideration of speed-related locomotive parameters, trackway morphology, and superposition allows for the speculation of the existence of cooperative or predatory relationships between theropod trackmakers that were differentiated by size or stages of ontogeny, but had similar foot structures. [ABSTRACT FROM AUTHOR]

The identification of additional Late Miocene (MN10, Late Vallesian) Decennatherium rex cranial remains at Batallones-10 (Torrejón de Velasco, Madrid Basin, Spain) provides valuable insights into the ontogenetic variability of this extinct giraffe. Most recovered specimens are adults, making the discovery of calves significant. The 2022 excavation yielded two juvenile hemimandibles, a maxilla, and a juvenile ossicone, likely from different individuals. The dental material represents one of the youngest specimens in the Batallones complex, with an estimated age of 4 months to 4.5 years, based on molar eruption stages seen in modern giraffes. The ossicone, resembling that of an adult male in shape but much smaller, mirrors the growth patterns in extant giraffes, where juvenile ossicones share adult proportions but are smaller. This ossicone was detached from the skull, typical for juveniles, as ossicones do not fuse with the cranial roof until later. This discovery broadens our understanding of giraffe ontogeny and includes the first giraffe calf ossicone found in the Iberian fossil record. [ABSTRACT FROM AUTHOR]

A new species Arachnocoris furtivinabis Ma, Du et Yao sp. nov. is described and illustrated, which represents the first fossil record of Arachnocoris, also the first record in the family Nabidae from Cenozoic Dominican amber. Based on the distinctive morphological characters in this new species, including antennomere II much shorter than twice of antennomere I, labial segment III slightly longer than segment II, and parameres round, it is differentiated from other species within Arachnocoris. Compared with the spider-webdwelling taxa of the extant and extinct species in Heteroptera, the evolution of predation strategies for this special group during the Miocene was discussed. [ABSTRACT FROM AUTHOR]

In the earliest published account of fish otoliths, Swedish physician and naturalist Magnus von Bromell (1679–1731) produced a brief but nonetheless remarkable publication titled 'De piscium lapillis', in which he declared 'fish pebbles' or 'ichthyoliths' (now known as otoliths) to be of great interest and strongly encouraged their study. A transcription and English translation of the original Latin is provided, with a discussion of the impact his study had on subsequent research. [ABSTRACT FROM AUTHOR]

It is the first time that the fossil footprints of a group of Middle Eocene elephant ancestors have been discovered in the Gonjo Basin, East Tibet Plateau. The Gonjo Formation is attributed to the Middle Eocene Epoch (U-Pb age = 44.7 ± 1.2 Ma) and consists mainly of purplish-red, medium- to coarse-grained sandstones, siltstones interbedded with mudstones, and conglomerates with sedimentary structures like ripple marks, rip-up clasts, and trough-cross bedding, suggesting fluvial-lacustrine systems. The group of fossil footprints has a characteristic oval-concave shape, and the toe impressions are absent. Some fossil footprints are overstepped with a pockmarked texture resembling Proboscipeda enigmatica. More than 165 fossil footprints of the group are relatively well-preserved with different diameters, which is evidence of highly social behavior and trackmakers of different ages, including calves, juveniles, adolescents, and adults. The size frequency of the fossil footprints enabled us to deduce the body mass, shoulder height, and hip-height distribution of the trackmakers that crossed the East Tibet Plateau 44.7 Ma ago. The trackmakers comprised an estimated average hip-height of 111.8 cm, an average shoulder height of 172.8 cm for males/155.9 cm for females, and an average body mass of approximately 1 218.1 kg for males/907.8 kg for females. The abundance of fossil footprints reveals that in the Middle Eocene Epoch, the environment was extraordinarily conducive for the elephant ancestors to live in the East Tibet region. [ABSTRACT FROM AUTHOR]

Burgess Shale-type deposits provide a wealth of information on the early evolution of animals. Questions that are central to understanding the exceptional preservation of these biotas and the paleoenvironments they inhabited may be obscured by the post-depositional alteration due to metamorphism at depth and weathering near the Earth's surface. Among over 50 Cambrian BST biotas, the Chengjiang and Qingjiang deposits are well known for their richness of soft-bodied taxa, fidelity of preservation, and Early Cambrian Age. While alteration via weathering has been well-investigated, the thermal maturity of the units bearing the two biotas has not yet been elucidated. Here we investigate peak metamorphic temperatures of the two deposits using two independent methods. Paleogeotemperature gradient analyses demonstrate that the most fossiliferous sections of the Chengjiang were buried at a maximum depth of ∼8 500 m in the Early Triassic, corresponding to ∼300 °C, while the type area of the Qingjiang biota was buried at a maximum depth of ∼8 700 m in the Early Jurassic, corresponding to ∼240 °C. Raman geothermometer analyses of fossil carbonaceous material demonstrate that peak temperatures varied across localities with different burial depth. The two productive sections of the Chengjiang biota were thermally altered at a peak temperature of approximately 300 °C, and the main locality of the Qingjiang biota experienced a peak temperature of 238 ± 22 °C. These results from two independent methods are concordant. Among BST deposits for which thermal maturity has been documented, the Qingjiang biota is the least thermally mature, and therefore holds promise for enriching our understanding of BST deposits. [ABSTRACT FROM AUTHOR]

The unusual daytime F-region Field-Aligned Irregularities (FAIs) were observed by the HCOPAR and the satellites at low latitudes on 13 June 2022. These irregularities survived from night-time to the following afternoon at 15:00 LT. During daytime, they appeared as fossil structures with low Doppler velocities and narrow spectral widths. These characteristics indicated that they drifted along the magnetic field lines without apparent zonal velocity to low latitudes. Combining the observations of the ICON satellite and the Hainan Digisonde, we derived the movement trails of these daytime irregularities. We attributed their generation to the rapid ascent of the F-layer due to the fluctuation of IMF Bz during the quiet geomagnetic conditions. Subsequently, the influence of the substorm on the low-latitude ionosphere was investigated and simulated. The substorm caused the intense Joule heating that enhanced the southward neutral winds, carrying the neutral compositional disturbances to low latitudes and resulting in a negative storm effect in Southeast Asia. The negative storm formed a low-density circumstance and slowed the dissipation of the daytime FAIs. These results may provide new insights into the generation of post-midnight irregularities and their relationship with daytime fossil structures. [ABSTRACT FROM AUTHOR]

Inferring the geographic mode of speciation is essential for explaining the generation and assembly of biodiversity, but has been rarely applied to the temperate flora of China. Fagus longipetiolata and F. lucida are a sister pair of beech species with largely overlapping ranges in subtropical China, however, little is known about the geographic mode of speciation and the formation of their sympatric distributions. In this study, we used IMa2 and fastsimcoal2 to simulate the speciation history of the two sisters. On the basis of 11 nuclear loci screened for 27 populations/species, their divergence time was estimated to 8.37 Mya by IMa2, and weak interspecific gene flow was detected. The simulation by fastsimcoal2 found that F. longipetiolata and F. lucida diverged ~8.53 Mya, then came into contact and hybridized at 0.8 Mya. The extended Bayesian skyline plots indicated that F. lucida began demographic expansion prior to the Pleistocene at 3 Mya, whereas F. longipetiolata increased its effective population size during the Quaternary, between 0.8 and 0.5 Mya. Ecological niche analysis and niche modelling showed that the two beeches had subtle niche differentiation and their projected distributions were largely overlapped across the late Quaternary. These results, coupled with well-studied fossil records in Fagus , demonstrate that these two beech species diverged allopatrically at the high latitudes of the Northern Hemisphere, and came into contact and hybridized with each other after successive migrations into subtropical (i.e. warm temperate) China recently. However, the two beeches may have developed strong intrinsic reproductive barriers due to long-term allopatry, allowing them to coexist in subtropical China. Our results illuminate the assembly history of the temperate woody flora in subtropical China, supporting that many relict temperate lineages in subtropical China may have established their populations recently. [ABSTRACT FROM AUTHOR]

A new, moderately large shell of a fossil species from the family Fasciolariidae Gray, 1853 is described from the Middle Miocene at Bengbreng Hill, West Java, Indonesia. The shell of this new species is related to species of the genus Clavilithes Swainson, 1840. The characteristics of a globular body whorl, low spire, and moderately long siphonal canal, distinguish it from species of the genus Clavilithes that have a fusiform shape, high spire, and usually long siphonal canal. This leads to its placement in a new genus Indolithes new genus. The new fossil species is compared with two other fossil species of Fasciolariidae from Java, Clavilithes fennemai (K. Martin, 1906) and C. verbeeki (K. Martin, 1895). [ABSTRACT FROM AUTHOR]

Mylodon darwinii is an extinct terrestrial species of sloth with a wide fossil record in South America, the record of the skin and hairs found from "La Cueva del Milodón", Chile. More than a century after the first studies on its hair, we aimed to redescribe the morphological characteristics of the hairs of M. darwinii by applying modern protocols of trichology and microscopy. Hair patterns were also compared with those of two other extinct species of sloths available in the literature. Hairs from mummified specimen housed in Museo de La Plata (Argentina) were analyzed through light and scanning electron microscopy to identify their cuticular and medullary patterns. Guard hairs lack medulla and have a wavy cuticle with irregular scale orientation, while underhairs have an amorphous cuticle pattern and no medulla. Hence, the former ones help in the diagnosis of the hair morphology of the species, while the latter ones do not. Differences found in the final product of each microscopy technique are discussed and should be considered in future research. The outcomes presented herein are a step further toward the understanding of evolutionary processes within Xenarthra, providing important data for such a poorly studied group that has only been recorded in Central and South America. [ABSTRACT FROM AUTHOR]

Premise Methods Results Conclusions Fossil infructescences and isolated fruits with characters of Malvoideae, a subfamily of Malvaceae (mallow family), were collected from early Eocene sediments in Chubut, Argentina. The main goals of this research are to describe and place these fossils systematically, and to explore their biogeographical implications.Fossils were collected at the Laguna del Hunco site, Huitrera Formation, Chubut, Patagonia, Argentina. They were prepared, photographed, and compared with extant and fossil infructescences and fruits of various families using herbarium material and literature.The infructescences are panicles with alternate arrangement of fruits. They bear the fruits on short pedicels that are subtended by a bract; the fruits display an infracarpelar disk and split to the base into five ovate sections interpreted as mericarps. Each mericarp is characterized by an acute apex and the presence of a longitudinal ridge. The isolated fruits show the same features as those on the infructescences. The fossils share unique features with members of the cosmopolitan family Malvaceae, subfamily Malvoideae.The fossils have a unique combination of characters that does not conform to any previously described genus, justifying the erection of a new genus and species, Uiher karuen. This new taxon constitutes the first known Malvoideae reproductive fossils of the Southern Hemisphere, expanding the distribution of Malvoideae during the early Eocene. [ABSTRACT FROM AUTHOR]

Two new genera and species of Ithonidae, i.e. Stictopolystoechotes sparsulus Gao, Xu et Wang gen. et sp. nov. and Pycnopolystoechotes striatus Gao, Xu et Wang gen. et sp. nov., are described from the Middle Jurassic Jiulongshan Formation, Inner Mongolia, China. The two new genera can be assigned to the Polystoechotes genus-group of Ithonidae by the combination of following characters: elongated forewing, Sc and RA fused distally, crossveins in radical sector sparse except for the gradate series, and simple CuP branches. The known wing markings among the Jurassic Polystoechotes genus-group were outlined, which suggested the diversification of wing markings was possibly positively associated with the species radiation of this lineage during this period. Moreover, a key to fossil genera of the Polystoechotes genus-group was provided. LSID: urn:lsid:zoobank.org:pub:CAEEFF67-876D-4709-BE4A-18F5AB04B01D Stictopolystoechotes: urn:lsid:zoobank.org:act:666ED6B2-B132-4CF4-BFB0-ED6B86EB30F4 Stictopolystoechotes sparsulus: urn:lsid:zoobank.org:act:6C96432B-205F-4F39-A647-3E0048169A92 Pycnopolystoechotes: urn:lsid:zoobank.org:act:1D1343DF-844E-4243-BAB9-242F6232EEBF Pycnopolystoechotes striatus: urn:lsid:zoobank.org:act:B4EFBE6B-5011-4103-A65F-77D65BEC0B85 [ABSTRACT FROM AUTHOR]

The Istiodactylidae is one of three ornithocheiroid pterosaur lineages, characterised by a large nasoantorbital fenestrae and labiolingually compressed teeth. Their remains have been reported from Early Cretaceous rocks of northeastern China and Western Europe. A new istiodactylid pterosaur from the upper part of the Yixian Formation (Jingangshan Member) of the Jehol Group, distributed in western Liaoning Province and neighbouring areas, is described on the basis of an incomplete specimen including the partial skull, forelimb and hindlimb bones, and pelvis. This individual, here designated as a referred specimen of Nurhachius (Nurhachius sp.) is a skeletally almost mature pterosaur with an estimated wingspan of 1.6 m. This specimen is not only the geologically oldest known occurrence of Nurhachius, but also a new component of the pterosaur assemblage of the Jingangshan Member, and provides new information on the pelvis and hindlimb of istiodactylids and the palaeobiology of this clade. Considering previous reports of the istiodactylid remains and the geological ages of the strata that yielded them, it is suggested that different istiodactylids existed in Europe and China during the late Barremian. [ABSTRACT FROM AUTHOR]

Examples of the small beetle family Cerylonidae are scarcely represented in the fossil record or at least are rarely determined as such by specialists. Until now, only one species of an extinct genus has been reliably identified to this family from Eocene Baltic amber. A new species, Mychocerus gedanensis McHugh et Ślipiński, sp. nov. (Coleoptera, Cerylonidae), is described from Eocene Baltic amber using X-ray micro-computed tomography (μCT) and optical microscopy. This is the first extinct species described for the subfamily Ceryloninae. It belongs to the extant genus Mychocerus Erichson, 1845, the largest cerylonid genus, which has a widespread distribution that until now excluded the continental parts of the Palaearctic. The new fossil species can be placed in the North American discretus group with two remarkably similar species (M. discretus (Casey, 1890) and M. striatus Sen Gupta & Crowson, 1973) based on the presence of a long and parallel-sided prosternal process. LSID: urn:lsid:zoobank.org:act:95EA100C-3323-472C-A17B-B75480B3FB18 [ABSTRACT FROM AUTHOR]

New fossil remains of Rhinocerotidae, dated from the early Late Miocene, were discovered from the lowermost part of the Irrawaddy Formation in the Tebingan area, Magway Region, central Myanmar. The Tebingan rhinoceros fossils, consisting of isolated teeth, maxillae, and mandibles, are assigned to three taxa: Brachypotherium perimense defined by a constricted protocone, a well-developed parastyle and broad upper teeth, to 'Brachypotherium' fatehjangense with a flat ectoloph, crochet, and the absence of tubercle at the entrance of the median valley. Other specimens were assigned to Rhinoceros sp. due to having a developed parastyle, crochet and a strong anterior cingulum and the absence of a constricted protocone and ante-crochet. The evolutionary history of Rhinocerotidae is poorly known in Southeast Asia, and few rhinoceros' species have been identified from the Irrawaddy Formation. The newly identified Rhinoceros specimens from the early Late Miocene Tebingan area are the oldest fossil records for Rhinoceros in Southeast Asia. The Tebingan mammal fauna is similar to the Nagri and Dhok Pathan faunas of the lower/middle Siwaliks of the Indian subcontinent, indicating the faunal exchange between these two regions in the late Neogene. [ABSTRACT FROM AUTHOR]

A fungal palynomorph corresponding to the fossil-species Lirasporis intergranifer R. Potonié & S.C.D. Sah, from the Middle Miocene lignite mine in Tomisławice (central Poland), is considered as the new combination Cancellidium intergraniferum (R. Potonié & S.C.D. Sah) G. Worobiec & E. Worobiec, comb. nov. The fossil-genus Lirasporis is treated as a synonym of the modern genus Cancellidium Tubaki. Cancellidium intergraniferum from the Miocene of Poland represents the first fossil record of Cancellidium outside Asia, the first record of this genus from Europe, and the northernmost known fossil occurrence of Cancellidium. Living representatives of Cancellidium seem to prefer warm and humid climates and, being aero-aquatic hyphomycetes, are usually associated with decaying woody remains in aquatic environments. A similar ecology is suggested for the fossil C. intergraniferum, which could be a reliable fungal non-pollen palynomorph proxy for palaeoclimatic and palaeoenvironmental reconstructions. [ABSTRACT FROM AUTHOR]

Aim: Many species have suffered anthropogenic range contraction and no longer occupy all available suitable environmental conditions. This is particularly problematic for the construction of habitat suitability models (HSMs), which assume that a species' contemporary range reflects its full species–environment relationship. HSMs therefore risk underestimating suitable environment areas, and misinforming conservation decisions. Incorporating historic (centuries‐old) records partly reduces this bias, but even these records are also subject to human disturbance. We incorporated fossil records of the critically endangered saiga antelope (Saiga tatarica, L., 1776), alongside historic and current records, into current and future habitat suitability models. Saiga has experienced drastic range contraction and may have a truncated species–environment relationship. The results allowed us to test whether its current habitat provides optimal environmental conditions, or whether saiga should be considered a refugee species. Location: Northern Hemisphere. Taxon: Saiga tatarica (Bovidae, Artiodactyla). Methods: We collated historic and fossil saiga occurrence records from published literature, museum archives and global databases. Modern occurrence records were obtained from the International Union for Conservation of Nature Red List assessment. Four bioclimatic variables were downloaded from Worldclim.org. HSMs were generated through Maxent, using the maxnet package in R. Three HSMs were developed: present only, present historic and present fossil. Each of these models was projected onto current and two future (2070) climate change scenarios. Results: Saiga fossil records increased the predicted suitable environment area by 783% and 1416% for current and future climate projections respectively. Our results suggest the saiga is not a refugee species but occupies only a portion of its potential environmental niche. The saiga's contemporary range is predicted environmentally suitable throughout all models and projections, and therefore in situ conservation management is recommended. Main Conclusions: This study highlights the importance of incorporating fossil records into HSMs to better understand species–environment relationships and develop more robust conservation strategies for appropriate endangered species. [ABSTRACT FROM AUTHOR]

The integration of morphological and molecular data is essential to understand the affinities of fossil taxa and spatio‐temporal evolutionary processes of organisms. However, homoplastic morphological characters can mislead the placement of fossil taxa and impact downstream analyses. Here, we provide an example of how to mitigate effectively the effect of morphological homoplasy on the placement of fossil taxa and biogeographic inferences of Cissampelideae. We assembled three data types, morphological data only, morphological data with a molecular scaffold and combined morphological and molecular data. By removing high‐level homoplastic morphological data or reweighting the morphological characters, we conducted 15 parsimony, 12 undated Bayesian and four dated Bayesian analyses. Our results show that the 14 selected Cissampelideae fossil taxa are placed poorly when based only on morphological data, but the addition of molecular scaffold and combination of morphological and molecular data greatly improve the resolution of fossil nodes. We raise the monotypic Stephania subg. Botryodiscia to generic status and discover that three fossils previously assigned to Stephania should be members of Diploclisia. The Bayesian tip‐dated tree recovered by removing homoplastic morphological characters with a Rescaled Consistency Index <0.25 has the highest stratigraphic fit and consequently generates more reasonable biogeographic reconstruction for Cissampelideae. Cissampelideae began to diversify in Asia in the latest Cretaceous and subsequently dispersed to South America around the Cretaceous–Palaeogene boundary. Two dispersal events from Asia to Africa occurred in the Early Eocene and the Late Eocene–Late Oligocene, respectively. These findings provide guidelines and practical methods for mitigating the effects of homoplastic morphological characters on fossil placements and Bayesian tip‐dating, as well as insights into the past tropical floristic exchanges among different continents. [ABSTRACT FROM AUTHOR]

Periderm is a well‐known structural feature with vital roles in protection of inner plant tissues and wound healing. Despite its importance to plant survival, knowledge of periderm occurrences outside the seed plants is limited and the evolutionary origins of periderm remain poorly explored. Here, we review the current knowledge of the taxonomic distribution of periderm in its two main forms – canonical periderm (periderm formed as a typical ontogenetic stage) and wound periderm (periderm produced as a self‐repair mechanism) – with a focus on major plant lineages, living and extinct. We supplement the published occurrences with data based on our own observations and experiments. This updated body of data reveals that the distribution of wound periderm is more widespread taxonomically than previously recognized and some living and extinct groups are capable of producing wound periderm, despite canonical periderm being absent from their normal developmental program. A critical review of canonical and wound periderms in extant and fossil lineages indicates that not all periderms are created equal. Their organisation is widely variable and the differences can be characterised in terms of variations in three structural features: (i) the consistency in orientation of periclinal walls within individual files of periderm cells; (ii) the lateral coordination of periclinal walls between adjacent cell files; and (iii) whether a cambial layer and conspicuous layering of inward and outward derivatives can be distinguished. Using a new system of scoring periderm structure based on these criteria, we characterise the level of organisation of canonical and wound periderms in different lineages. Looking at periderms through the lens provided by their level of organisation reveals that the traditional image of periderm as a single generalised feature, is best viewed as a continuum of structural configurations that are all predicated by the same basic process (periclinal divisions), but can fall anywhere between very loosely organized (diffuse periclinal growth) to very tightly coordinated (organized periclinal growth). Overall, wound periderms in both seed plants and seed‐free plants have lower degrees of organisation than canonical periderms, which may be due to their initiation in response to inherently disruptive traumatic events. Wound and canonical periderms of seed plants have higher degrees of organisation than those of seed‐free plants, possibly due to co‐option of the programs responsible for organizing their vascular cambial growth. Given the importance of wound periderm to plant survival, its widespread taxonomic distribution, and its early occurrence in the fossil record, we hypothesise that wound periderm may have had a single origin in euphyllophytes and canonical periderm may have originated separately in different lineages by co‐option of the basic regulatory toolkit of wound periderm formation. In one evolutionary scenario, wound periderm regulators activated initially by tissue tearing due to tensional stresses elicited by woody growth underwent heterochronic change that switched their activation trigger from tissue tearing to the tensional stresses that precede it, with corresponding changes in the signalling that triggered the regulatory cascade of periderm development from tearing‐induced signals to signalling induced by tension in cells. [ABSTRACT FROM AUTHOR]

Elongated biconvex Carex fossil fruits are relatively common in fossil assemblages, but they are of much uncertain taxonomic affinity. Three fossil-species have been erected to accommodate the materials from the respective type localities (C. klarae, C. paucifloriformis and C. paucifloroides) and a number of superficially similar-looking fossils were reported from other sites. The formerly proposed affinities mostly pointed to the extant C. pauciflora (subgen. Euthyceras) or Carex sect. Cyperoideae (subgen. Vignea), depending on the authors. But despite the similar superficial resemblance of the fossil remains to these not very closely related sedge taxa, other groups are also possible matches. We used a comparative approach employing stereomicroscope and SEM to analyze the affinities of several Old World "mummified" fossils (ca. 23 to 0.1 Ma) of elongated biconvex fruits. Several samples showed a fair preservation of previously unattested microscopic characters. In particular, one of them allowed us to detect an indirect record of fine silica body morphologies (impressions) on the periclinal walls, which permitted the sound taxonomic placement of the remains from the Miocene of Siberia as a Carex sect. Cyperoideae. In all the other fossils analyzed, the epidermal cell outline and the central position of the main silica body were sufficient to discard assignment to subgen. Euthyceras, despite a purported affinity to C. pauciflora reported in previous literature. In the absence of detailed information on silica bodies, epidermal cell (exocarp) details in fossil specimens do not seem to be determinant for the systematic placement. However, the addition of diagnostic style characters pointed to sect. Cyperoideae as the best match with the available information. Our data support a continued presence of Carex sect. Cyperoideae in the Old World since the Miocene, which candidates Eurasia as a possible place of origin for it, despite DNA-based reconstructions alone proposed North America. This study underlines the importance of detailed taxonomic studies to properly address the identity of fossils and unravel the biogeographic history of plants. [ABSTRACT FROM AUTHOR]

Southeastern Patagonia's (49° S) post‐glacial history inferred from high Andean lake sediments provides new insights regarding Late Pleistocene and Holocene vegetation dynamics at the eastern margin of the Southern Patagonian Icefield. The fossil records of pollen, charcoal and geochemical data from tephra layers from Laguna Chiquita and Laguna Gemelas Este were analysed to reveal past landscape dynamics related to vegetation changes, fire and volcanic events from ca. 15 200 cal a bp to the present. Nothofagus forest expanded over shrubland communities sometime between 15 200 and 4600 cal a bp, along with at least three disturbance sources related to the volcanic eruptions of Lautaro, Aguilera and Hudson, important local fire episodes, and neoglacial advances. Major charcoal deposition reveals moderate fire activity during the Late Pleistocene related to an open landscape characterised by a grass/shrub steppe. Local glacier advances may have affected the Laguna Gemelas Este sedimentation. Tephra deposition events do not correlate to vegetation changes inferred from the Laguna Gemelas Este and Laguna Chiquita pollen records. Late Holocene eastern Andean forest changes and fire activity at 49° S match other southern palaeoenvironmental records (50–52° S) suggesting that changes in the Southern Westerly Wind latitudinal position and intensity drove major palaeovegetation and fire dynamics before the European settlement. In the last centuries, fire and vegetation changes have been closely related to an increase in local ignition sources and the introduction of alien species. [ABSTRACT FROM AUTHOR]

Paleopathology, the study of diseases and injuries from the fossil record, allows for a unique view into the life of prehistoric animals. Pathologies have nowadays been described in nearly all groups of fossil vertebrates, especially dinosaurs. Despite the large number of skeletons, pathologies had never been reported in the sauropodomorph Plateosaurus trossingensis. Here we describe the first pathologies of Plateosaurus using two individuals with pathologies in the chevrons of the tail, from the Upper Triassic of Trossingen, SW Germany. The two specimens each contain three consecutive pathological chevrons. Our results show that the pathologies were caused by external trauma in one individual and potentially tendinous trauma in the other. Healing of the lesions allowed survival of both animals. Using additional pathological specimens found in other collections and from multiple localities, we observe that 14.8% of all individuals of Plateosaurus contain pathologies within their chevrons, suggesting it was a vulnerable bone. [ABSTRACT FROM AUTHOR]

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]

Amber captures a snapshot of life and death from millions of years in the past. Here, the fate of three fossil Darwin wasps in Baltic amber is virtually dissected with the help of micro-CT scanning, to better understand the taphonomic processes that affected their preservation. The states of the fossils range from nearly perfect preservation, including remains of internal organs, to empty casts that were strongly affected by decomposition. We describe the three specimens as new taxa, Osparvis aurorae gen. et sp. nov., Grana harveydenti gen. et sp. nov. and Xorides? romeo sp. nov. Based on the taphonomic and morphological interpretations, we conclude that two specimens were trapped alive, and the third ended up in resin post-mortem. The morphology and classification of the specimens provide clues regarding their ecology, and we discuss their likely hosts and parasitation modes. Taken together, our three wasp fossils showcase how an integrative analysis of amber taphonomy, taxonomic association and morphology can shed light onto past biodiversity and offer valuable insights for interpreting their evolutionary history. [ABSTRACT FROM AUTHOR]

Pterosaurs, flying reptiles that lived during the Mesozoic era, were the first vertebrates to develop powered flight. Despite being patchy, the pterosaur fossil record extends worldwide, being quite diverse at the Araripe Basin, Brazil. The Romualdo Formation (Aptian-Albian), a Konservat Lagerstätten rich in calcareous concretions, has yielded several of these exceptionally well-preserved, three-dimensional fossils. MN 4727-V, the focus of the present study, consists exclusively of three-dimensionally preserved post-cranial axial and appendicular elements. The anatomy suggests that MN 4727-V is a pteranodontoid since it exhibits an enlarged, warped deltopectoral crest and a subtriangular distal articulation of the humerus. The phylogenetic analysis recovered MN 4727-V as an anhanguerid by the combination of the following characters: scapula substantially shorter than the coracoid (sca/co < 0.80), and posterior expansion of the sternal articulation of the coracoid. The presence of elliptical-shaped, dorsomedially inclined depressions on the dorsal surface of the prezygapophyses of the preserved cervicals has never been reported for any other anhanguerid, although they might not be diagnostic to MN 4727-V. The tail bears unique middle caudals that exhibit ventral projections, a character previously reported only for Anhanguera piscator. The wingspan of MN 4727-V, a juvenile individual, was estimated to be about 3.9 metres. [ABSTRACT FROM AUTHOR]