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Diatomite deposits of the lacustrine Truckee Formation near Hazen, Northern Nevada, are of Miocene age (ca. 10.3 million years old) and consist of varved deposits within commercial mines. These exposed deposits have been primary source of paleontological samples of stickleback fish fossils (Gasterosteous doryssus) spanning 100,000 years. These samples have revealed stasis, rapid morphological and genetic evolution, and local extinction of G. doryssus against a background of changing diatom communities. Here, we draw on geological, limnological, anthropogenic, and bibliographical data to illustrate the geographic and paleontological context of the Hazen diatomite deposits. We include a stratigraphic section describing lithology and stickleback specimen frequency at a 1 mm resolution. This paper should help researchers identify patterns in fossil site distribution and better understand the geological processes that have shaped the area, spurring new sampling and future research.

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.

Biomechanical studies in sauropod dinosaurs are mainly focused on neck posture and feeding strategy. Few works investigate other aspects such as tail movement and function, especially in the clade Titanosauria, the most diverse within Neosauropoda. This study applied biomechanical concepts of neutral pose (cartilaginous neutral pose) and range of motion to verify the shape and direction of the caudal region of the advanced titanosaurs Adamantisaurus mezzalirai and Baurutitan britoi, in addition to comparing it with other titanosaurs (e.g., Arrudatitan maximus, Lirainosaurus astibiae, and Trigonosaurus pricei). As a result, the tails analyzed have a sigmoidal‐convex shape, probably close to the ground (but not touching it). The sigmoidal‐convex shape could increase the moment arm for the M. caudofemoralis longus, making it possible to use the tail as a fifth stabilizing member. This work expands our knowledge about sauropod dinosaurs by exposing a diversity of shapes for the tails of titanosaur sauropods and brings new possibilities for how these dinosaurs could use their tails. [ABSTRACT FROM AUTHOR]

The mustelid assemblage from Hunas is represented by seven species: Gulo gulo gulo (Linnaeus, 1758), Meles meles (Linnaeus, 1758), Lutra lutra groissii Heller, 1983, Martes martes (Linnaeus, 1758), Mustela putorius Linnaeus, 1758, Mustela erminea Linnaeus, 1758 and Mustela nivalis Linnaeus, 1766. Most species have been found in the G1-G3 complex, while their remains in other layers are rare. The guild is dominated by remains of Mustela nivalis, for which well-preserved and stratified material shows a large, robust weasel, with a notable predominance of males. The morphology of Mustela nivalis, together with the occurrence of Lutra lutra (Linnaeus, 1758), allowed us to estimate the age of the horizon at MIS 7. [ABSTRACT FROM AUTHOR]

The larvae of Neuroptera are predators that feed by injecting bioactive compounds into their prey and then suctioning the fluids through modified mouthparts. We explore the evolutionary history of this feeding structure through the examination of a new fossil larva preserved in Late Cretaceous Kachin amber, which we describe as new genus and species, Electroxipheus veneficus gen et sp. nov. X-ray phase-contrast microtomography enabled us to study the anatomy of the larva in 3D, including the structure of the mouthparts and that of the venom delivery system. The specimen exhibited a unique combination of morphological traits not found in any known fossil or extant lacewing, including an unusual structure of the antenna. Phylogenetic analyses, incorporating a selection of living and fossil larval Neuroptera and enforcing maximum parsimony and Bayesian inference, identified the larva as belonging to the stem group Mantispoidea. The larva shows that the anatomy of the feeding and venom-delivery apparatus has remained unchanged in Neuroptera from the Cretaceous to the present. The morphology of the specimen suggests that it was an active predator, in contrast with the scarcely mobile, specialized relatives, like mantispids and berothids. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Location Time Period Major Taxa Studied Methods Results Main Conclusions To determine the degree to which assemblages of planktonic foraminifera track thermal conditions.The world's oceans.The last 700,000 years of glacial–interglacial cycles.Planktonic foraminifera.We investigate assemblage dynamics in planktonic foraminifera in response to temperature changes using a global dataset of Quaternary planktonic foraminifera, together with a coupled Atmosphere–Ocean General Circulation Model (AOGCM) at 8000‐year resolution. We use ‘thermal deviance’ to assess assemblage responses to climate change, defined as the difference between the temperature at a given location and the bio‐indicated temperature (i.e., the abundance‐weighted average of estimated temperature optima for the species present).Assemblages generally tracked annual mean temperature changes through compositional turnover, but thermal deviances are evident under certain conditions. The coldest‐adapted species persisted in polar regions during warming but were not joined by additional immigrants, resulting in minimal assemblage turnover. The warmest‐adapted species persisted in equatorial regions during cooling with similarly minimal assemblage change. Assemblages at mid‐latitudes mostly tracked temperature cooling and warming.Planktonic foraminiferal assemblages were generally able to track or endure temperature changes: as climate warmed or cooled, bio‐indicated temperature also became warmer or cooler, although to a variable degree. At polar sites under warming and at equatorial sites under cooling, the change in bio‐indicated temperature was less than, or even opposite to, what would be expected from estimated environmental change. Nevertheless, all studied species persisted across the study interval, regardless of thermal deviance—a result that highlights the resilience and inertia of planktonic foraminifera on an assemblage level to the last 700,000 years of climate change. [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]

A partial ichthyosaur skeleton from the Toarcian (Lower Jurassic) bituminous shales of the 'Schistes Carton' unit of southern Luxembourg is described and illustrated. In addition, associated remnant soft tissues are analyzed using a combination of imaging and molecular techniques. The fossil (MNHNL TV344) comprises scattered appendicular elements, together with a consecutive series of semi-articulated vertebrae surrounded by extensive soft-tissue remains. We conclude that TV344 represents a skeletally immature individual (possibly of the genus Stenopterygius) and that the soft parts primarily consist of fossilized skin, including the epidermis (with embedded melanophore pigment cells and melanosome organelles) and dermis. Ground sections of dorsal ribs display cortical microstructures reminiscent of lines of arrested growth (LAGs), providing an opportunity for a tentative age determination of the animal at the time of death (>3 years). It is further inferred that the exceptional preservation of TV344 was facilitated by seafloor dysoxia/anoxia with periodical intervals of oxygenation, which triggered phosphatization and the subsequent formation of a carbonate concretion. [ABSTRACT FROM AUTHOR]

Neolicaphrium recens (Mammalia, Litopterna) was a slender South American Native Ungulate (SANU). The assessment of its body size is a big challenge because there are no living representatives and no clear close morphological analogues. In this contribution, we report for the first time a femur of N. recens exhumed from Late Pleistocene sediments of Uruguay, improving the knowledge of the postcranial skeleton of the species. This stylopodial element is important for doing palaeobiological inferences, including estimating the body mass. We performed body mass estimations by previous allometric equations. As a method to directly test the models and their usefulness in fossils, we applied the equations on six specimens of extant deers of known body weight and with skeletons preserved. According to the obtained data, the transverse width at the middle of the diaphysis and the circumference of the bone at that level can be used with confidence to estimate the body mass of fossil ungulates. We point out a set of more probable values of body mass for N. recens: 28.76298 ± 10.6412, 27.78496 ± 8.0576, and 26.72 ± 10.42 kg. Morphological variables as well as the models for estimating body masses in fossils are widely discussed. [ABSTRACT FROM AUTHOR]

Fossil-Lagerstätten are amongst the most important windows onto the paleobiology of ancient ecosystems. Inconsistencies surrounding what constitutes a Lagerstätte limits our ability to compare sites and thus their scientific potential. Here, we provide a modern and utilitarian classification scheme for Konservat-Lagerstätten, allowing for more consistent and improved scientific discourse. [ABSTRACT FROM AUTHOR]

Abstract Background The fossil record provides the unique opportunity to observe evolution over millions of years, but is known to be incomplete. While incompleteness varies spatially and is hard to estimate for empirical sections, computer simulations of geological processes can be used to examine the effects of the incompleteness in silico. We combine simulations of different modes of evolution (stasis, (un)biased random walks) with deposition of carbonate platforms strata to examine how well the mode of evolution can be recovered from fossil time series, and how test results vary between different positions in the carbonate platform and multiple stratigraphic architectures generated by different sea level curves. Results Stratigraphic architecture and position along an onshore-offshore gradient has only a small influence on the mode of evolution recovered by statistical tests. For simulations of random walks, support for the correct mode decreases with time series length. Visual examination of trait evolution in lineages shows that rather than stratigraphic incompleteness, maximum hiatus duration determines how much fossil time series differ from the original evolutionary process. Gradual directional evolution is more susceptible to stratigraphic effects, turning it into punctuated evolution. In contrast, stasis remains unaffected. Conclusions • Fossil time series favor the recognition of both stasis and complex, punctuated modes of evolution. • Not stratigraphic incompleteness, but the presence of rare, prolonged gaps has the largest effect on trait evolution. This suggests that incomplete sections with regular hiatus frequency and durations can potentially preserve evolutionary history without major biases. Understanding external controls on stratigraphic architectures such as sea level fluctuations is crucial for distinguishing between stratigraphic effects and genuine evolutionary process.

Conservation paleobiology is a cross-disciplinary fi eld that utilizes the geohistorical record of past life on Earth to inform present-day decisions in conservation and restoration and assist in planning for future natural resource management. However, information on how past ecosystems and species responded to environmental change over decadal to millennial timescales is rarely incorporated into conservation and restoration decision-making. To heighten awareness among conservation and restoration practitioners of the relevance of geohistorical data and to bridge the gap between research and implementation in conservation paleobiology, we proposed a Research Topic titled "Integrating Conservation Biology and Paleobiology to Manage Biodiversity and Ecosystems in a Changing World". The 21 articles subsequently published demonstrate the diversity and breadth of geohistorical information available to resource management and the challenges of translating these results into conservation practice and policy. Here we discuss the lessons we learned from editing the Research Topic and suggest a pathway forward for conservation paleobiologists who aspire to generate actionable research results to solve current problems in biodiversity conservation and ecological restoration. [ABSTRACT FROM AUTHOR]

Objectives: Estimation of body mass from skeletal metrics can reveal important insights into the paleobiology of archeological or fossil remains. The standard approach constructs predictive equations from postcrania, but studies have questioned the reliability of traditional measures. Here, we examine several skeletal features to assess their accuracy in predicting body mass. Materials and Methods: Antemortem mass measurements were compared with common skeletal dimensions from the same animals postmortem, using 115 rhesus macaques (male: n = 43; female: n = 72). Individuals were divided into training (n = 58) and test samples (n = 57) to build and assess Ordinary Least Squares or multivariate regressions by residual sum of squares (RSS) and AIC weights. A leave‐one‐out approach was implemented to formulate the best fit multivariate models, which were compared against a univariate and a previously published catarrhine body‐mass estimation model. Results: Femur circumference represented the best univariate model. The best model overall was composed of four variables (femur, tibia and fibula circumference and humerus length). By RSS and AICw, models built from rhesus macaque data (RSS = 26.91, AIC = −20.66) better predicted body mass than did the catarrhine model (RSS = 65.47, AIC = 20.24). Conclusion: Body mass in rhesus macaques is best predicted by a 4‐variable equation composed of humerus length and hind limb midshaft circumferences. Comparison of models built from the macaque versus the catarrhine data highlight the importance of taxonomic specificity in predicting body mass. This paper provides a valuable dataset of combined somatic and skeletal data in a primate, which can be used to build body mass equations for fragmentary fossil evidence. [ABSTRACT FROM AUTHOR]

The presence of Dromornithidae in the Australian Cenozoic fossil record was first reported in 1872, yet although eight species and hundreds of specimens are known, key information on their morphology remains elusive. This is especially so for their skulls, which contributes to a lack of resolution regarding their relationships within Galloanserae. The skull of the Pleistocene dromornithid, Genyornis newtoni, was initially described in 1913. Additional fossils of this species have since been discovered and understanding of avian skull osteology, arthrology, and myological correlates has greatly advanced. Here we present a complete redescription of the skull of Genyornis newtoni, updating knowledge on its morphology, soft-tissue correlates, and palaeobiology. We explore the diversity within Dromornithidae and make comprehensive comparisons to fossil and extant galloanserans. Furthermore, we expand on the homologies of skull muscles, especially regarding the jaw adductors and address the conflicting and unstable placement of dromornithids within Galloanserae. Findings support generic distinction of Genyornis newtoni, and do not support the close association of Dromornithidae and Gastornithidae. We thus recommend removal of the dromornithids from the Gastornithiformes. Considering character polarities, the results of our phylogenetic analyses, and palaeogeography, our findings instead support the alternative hypotheses, of dromornithids within, or close to, the Suborder Anhimae with Anseriformes. [ABSTRACT FROM AUTHOR]

Hymenoptera is the fourth-most diverse insect order today, including wasps, bees, bumblebees, and ants. They show a wide panoply of modes of life, such as herbivory, predation, parasitoidism, pollination, and eusociality. This group also includes a great number of extinct species from both amber and compression outcrops. Hymenopterans probably originated in the Paleozoic, although their oldest record is from the Middle or Late Triassic, and their diversity expanded since the Cretaceous. Here, we present a review of the Hymenoptera in Lower Cretaceous ambers from Lebanon (Barremian) and Spain (Albian), which is pivotal for the study of hymenopteran evolution. Hymenoptera in Lebanese ambers are represented by 32 species in 22 genera within 15 families, while in Spanish ambers, they correspond to 49 species in 40 genera within 18 families. Most of these species belong to the 'Parasitica', and only a few species have been assigned to the Aculeata. The group 'Symphyta' is represented by one species in Spanish amber. The paleobiogeography and possible paleobiologies of the species in these ambers are reviewed. Furthermore, checklists for all Hymenoptera species in Lebanese and Spanish ambers are provided. [ABSTRACT FROM AUTHOR]

Mantle convection plays a fundamental role in driving evolution of oceanic and continental lithosphere. In turn it impacts a broad suite of processes operating at or close to Earth's surface including landscape evolution, glacio‐eustasy, magmatism, and climate. A variety of theoretical approaches now exist to simulate mantle convection. Outputs from such simulations are being used to parameterize models of landscape evolution and basin formation. However, the substantial body of existing simulations has generated a variety of conflicting views on the history of dynamic topography, its evolution and key parameters for modeling mantle flow. The focus of this study is on developing strategies to use large‐scale quantitative stratigraphic observations to assess model predictions and identify simulation parameters that generate realistic predictions of Earth surface evolution. Spot measurements of uplift or subsidence provide useful target observations for models of dynamic topography, but finding areas where tectonics have not also influenced vertical motions is challenging. To address this issue, we use large inventories of stratigraphic data from across North America with contextual geophysical and geodetic data to constrain the regional uplift and subsidence history. We demonstrate that a suite of typical geodynamic simulations struggle to match the amplitude, polarity and timing of observed vertical motions. Building on recent seismological advances, we then explore strategies for understanding patterns of continental uplift and subsidence that incorporate (and test) predicted evolution of the lithosphere, asthenosphere and deep mantle. Our results demonstrate the importance of contributions from the uppermost mantle in driving vertical motions of continental interiors. Key Points: Large‐scale digital inventories of stratigraphic observations used to test predictions from mantle convection simulationsUseful diagnostics include net uplift and subsidence, absolute elevations, paleo‐water depthsUpper mantle thermo‐mechanical evolution—crucial for assessing sub‐plate support—constrained using stratigraphy [ABSTRACT FROM AUTHOR]

Eurynotoidiformes are a little‐known group of actinopterygian fishes from the Permian of European Russia, characterized by the possession of multicuspid marginal teeth arranged in a single row. Morphologically, the teeth resemble those of Recent Cichlidae, Acanthuridae, Siganidae or Serrasalmidae, suggesting similar trophic adaptations related to herbivory. Tooth histology is similar to the majority of basal actinopterygians (composed of dentine, acrodin and collar enamel). Teeth are ankylosed in their attachment, and labial pleurodont in implantation, strengthening the tooth. The multicuspid tooth crowns derive from conical teeth of predatory or omnivorous ancestors, analogous to the evolution of multicuspid teeth in cichlid fishes. Tooth replacement in eurynotoidiforms is most comparable to an alternating pattern, with a possible simultaneous, unilateral replacement occurring in the whole jaw, similar to characiform fishes. Replacement teeth were formed extraosseously. Teeth of the inner dental arcade were conical. Based on comparisons with the teeth of extant actinopterygians specialized for herbivory, along with functional morphological analysis and consideration of wear patterns, we hypothesize that eurynotoidiforms represent the oldest known actinopterygians specialized for herbivory. Several strategies of herbivory in Recent actinopterygians were already realized by eurynotoidiforms as early as the Late Palaeozoic (middle and late Permian): grazing/cutting filamentous algae (Lapkosubia spp., Isadia suchonensis), browsing/biting off macrophyte fragments (Isadia aristoviensis), scraping/harvesting periphyton from hard substrates (Isadia opokiensis, I. arefievi). However, notable morphological differences in the jaws (elongate) and tooth arrangement (homodont along the jaw, functional teeth separated) suggest that this Permian experiment in herbivory followed different pathways compared to extant taxa. [ABSTRACT FROM AUTHOR]

This comprehensive study examines fossil remains from Niedźwiedzia Cave in the Eastern Sudetes, offering detailed insights into the palaeobiology and adversities encountered by the Pleistocene cave bear Ursus spelaeus ingressus. Emphasising habitual cave use for hibernation and a primarily herbivorous diet, the findings attribute mortality to resource scarcity during hibernation and habitat fragmentation amid climate shifts. Taphonomic analysis indicates that the cave was extensively used by successive generations of bears, virtually unexposed to the impact of predators. The study also reveals that alkaline conditions developed in the cave during the post-depositional taphonomic processes. Mortality patterns, notably among juveniles, imply dwindling resources, indicative of environmental instability. Skeletal examination reveals a high incidence of forelimb fractures, indicating risks during activities like digging or confrontations. Palaeopathological evidence unveils vulnerabilities to tuberculosis, abscesses, rickets, and injuries, elucidating mobility challenges. The cave's silts exhibit a high zinc concentration, potentially derived from successive bear generations consuming zinc-rich plants. This study illuminates the lives of late cave bears, elucidating unique environmental hurdles faced near their species' end. [ABSTRACT FROM AUTHOR]

Summary: A minuscule fraction of the Earth's paleobiological diversity is preserved in the geological record as fossils. What plant remnants have withstood taphonomic filtering, fragmentation, and alteration in their journey to become part of the fossil record provide unique information on how plants functioned in paleo‐ecosystems through their traits. Plant traits are measurable morphological, anatomical, physiological, biochemical, or phenological characteristics that potentially affect their environment and fitness. Here, we review the rich literature of paleobotany, through the lens of contemporary trait‐based ecology, to evaluate which well‐established extant plant traits hold the greatest promise for application to fossils. In particular, we focus on fossil plant functional traits, those measurable properties of leaf, stem, reproductive, or whole plant fossils that offer insights into the functioning of the plant when alive. The limitations of a trait‐based approach in paleobotany are considerable. However, in our critical assessment of over 30 extant traits we present an initial, semi‐quantitative ranking of 26 paleo‐functional traits based on taphonomic and methodological criteria on the potential of those traits to impact Earth system processes, and for that impact to be quantifiable. We demonstrate how valuable inferences on paleo‐ecosystem processes (pollination biology, herbivory), past nutrient cycles, paleobiogeography, paleo‐demography (life history), and Earth system history can be derived through the application of paleo‐functional traits to fossil plants. [ABSTRACT FROM AUTHOR]

The southernmost population of Eurasian water vole (Arvicola amphibius) inhabited Lake Hula in the upper Jordan Valley until the lake was drained in the 1950s. Considering the continuous conservation and restoration initiatives in the Hula Valley, we set out to verify the extinction of the Hula water vole population using trap surveys, field sign surveys, and owl pellets' content. Having confirmed its recent extirpation, we used museum and archaeological specimens to study the morphological and genetic similarity of the extirpated Hula water voles to both modern conspecifics in Eurasia and to local Pleistocene specimens. Our results suggest that the Hula population represented an admixture of extinct local Pleistocene and extant, probably European, ancestors. The recent anthropogenic extirpation of this unique population could justify its reintroduction. Species distribution modelling, however, suggests future deterioration of habitat suitability over the coming decades. This calls for careful consideration of how sustainable a reintroduction would be. [ABSTRACT FROM AUTHOR]

Summary: Fossil bones have been studied by paleontologists for centuries. Despite this, empirical knowledge regarding the progression of biomolecular (soft) tissue diagenesis within ancient bone is limited; this is particularly the case for specimens spanning Pleistocene directly into pre-Ice Age strata. A nanoscopic approach is reported herein that facilitates direct imaging, and thus empirical observation, of soft tissue preservation state. Presented data include the first extensive nanoscopic (up to 150,000× magnification), three-dimensional (3D) images of ancient bone protein and vasculature; chemical signals consistent with collagen protein and membrane lipids, respectively, are also localized to these structures. These findings support the analyzed permafrost bones are not fully fossilized but rather represent subfossil bone tissue as they preserve an underlying collagen framework. Extension of these methods to specimens spanning the geologic record will help reveal changes biomolecular tissues undergo during fossilization and is a potential proxy approach for screening specimen suitability for molecular sequencing.

Summary: Tyrannosauroids are a clade of theropod dinosaur taxa that varied greatly in their body size distribution. We investigated the feeding performance of six tyrannosaur genera of variable body size and skull morphology. We used 3D finite element analysis to test whether skull shape becomes more or less resistant to feeding-induced forces. Cranial and mandibular models were scaled by adult Tyrannosaurus’s surface area to analyze the influence of shape on skull function. It was found that Tyrannosaurus experienced higher absolute stresses compared to small-bodied relatives. When surface area values were equalized across genera to account for the effect of size and test efficiency of skull shape, smaller individuals experience notably greater stresses than larger relatives due to the robust cranial osteology characterized in the allometry of tyrannosaurids. These results may indicate that the wide crania of tyrannosaurids convey a functional advantage that basal tyrannosauroids, juvenile tyrannosauroids, and alioramins lacked.

Sphenodontians are a group of vertebrates with a vast taxonomic diversity and worldwide distribution of their fossils. Although they have been the subject of many studies on their phylogeny and morphology, those focused on their paleobiology are still scarce. We present here the osteohistology of eleven postcranial elements corresponding to a single specimen of Priosphenodon avelasi, an eilenodontine sphenodontian from Cenomanian–Turonian rocks of Río Negro (Argentina). The bone samples described here share a parallel-fibered type of matrix. The degree of vascularization varies in all the samples, but none of them present a significant density of primary vascular canals. Lines of arrested growth were observed in all appendicular elements, being better preserved in the humerus, radius and fibula. Extrinsic fibers were observed only in reduced regions of the cortex of the ulna and in one of the phalanges. The primary bone tissue suggests that the specimen had a relatively low growth rate with alternation between slow and accelerated stages. The latter could explain why this taxon reached the largest sizes of all known sphenodontians.

Understanding variation of traits within and among species through time and across space is central to many questions in biology. Many resources assemble species-level trait data, but the data and metadata underlying those trait measurements are often not reported. Here, we introduce FuTRES (Functional Trait Resource for Environmental Studies; pronounced few-tress), an online datastore and community resource for individual-level trait reporting that utilizes a semantic framework. FuTRES already stores millions of trait measurements for paleobiological, zooarchaeological, and modern specimens, with a current focus on mammals. We compare dynamically derived extant mammal species' body size measurements in FuTRES with summary values from other compilations, highlighting potential issues with simply reporting a single mean estimate. We then show that individual-level data improve estimates of body mass-including uncertainty-for zooarchaeological specimens. FuTRES facilitates trait data integration and discoverability, accelerating new research agendas, especially scaling from intra- to interspecific trait variability.

In the last 5 decades, paleontological research has exploded where fossils have enabled robust dating of rocks, improved understanding of origination/extinction rates or mass extinction events, biogeography, adaptive strategies, and many more. New molecular technologies have enabled intensive analyses of vertebrates and invertebrates, plant fossils, fossilized microbes, trace fossils, and fossil molecules, alike. Paleontological research has become interdisciplinary with inputs from geology, chemistry, biology, astronomy, and archaeology. Herein, we review the principles of promising molecular technologies and explore their applications and limitations vis-à-vis paleontological research. This review will attempt to provide a roadmap that can be used for future research directions. Advanced chemical imaging provides the ability to identify and quantify chemical characteristics to evaluate taphonomic damage, original biological structures, or fossils microbes. Molecular methods (e.g., molecular clock, DNA barcode, racemization dating, and biomarkers) offer a unique source of information and provide robust clues into the co-evolution of life in modern and past environments. Two main limitations are noted and include an exceptional preservation of the organic material, which is not always the case, and the complexity and cost of the instruments involved in the analyses. These difficulties are limiting the factual applications in paleontological analysis. Although very little research has been carried out on the aforementioned methods, they however, provide improved answers to highly debated and unsolved biological and climatic issues and a window to better understanding the origin of life. Biomarker proxies will be further developed and refined to answer emerging questions in the Quaternary Period. [ABSTRACT FROM AUTHOR]

Pareiasaurs were among the world's first large terrestrial tetrapods, first appearing during the Guadalupian Epoch, and were later widespread across Pangea during the Lopingian where they formed a significant part of the large herbivore guild. The Bradysauria of the Lower Beaufort Group of the Karoo Basin of South Africa are among the oldest pareiasaurs, yet little is known of their palaeobiology. Here, we present the first volumetric body mass estimate and a new in vivo reconstruction of the earliest Karoo pareiasaur, and the phylogenetically basal-most pareiasaur, Bradysaurus baini, based on two almost complete adult mounted skeletons. Using 3D photogrammetric models of the two skeletons, we calculated a possible body mass range for B. baini by applying different densities for living tissue to reconstructions of differing soft tissue mass. Considering the larger adult Bradysaurus specimen, our volumetric body masses range from a minimum of 851.4 kg to a maximum of 1,276.5 kg, with an overall mean body mass of 1,022 kg, approximately the body weight of a large domestic cow. The study provides a more precise estimate of body mass in early members of Pareiasauridae, and we suggest that they were somewhat smaller than some late Permian taxa such as Scutosaurus karpinskii. [ABSTRACT FROM AUTHOR]

Classic depictions of human evolutionary ecology cast Homo as predator and other hominins, including Paranthropus robustus, as prey. Such hypotheses rest on a small number of fossils that exhibit evidence of carnivore predation, including the iconic SK 54 cranium from Swartkrans in South Africa. Here we demonstrate that the SK 54 cranium shares its closest affinities with H. erectus sensu lato rather than P. robustus. Demonstrating that Homo was prey for leopards at Swartkrans weakens the historically significant hypothesis that Homo was better able to avoid predation because of being behaviourally and technologically advanced compared to Paranthropus. Subsequent ideas about hominin palaeobiology derived from this hypothesis warrant reconsideration. [ABSTRACT FROM AUTHOR]

In recent years, new findings and new methods (stable isotopes of oxygen, zinc, and nitrogen; 2D and 3D modeling; and geometric morphometric analyses of the teeth) have enhanced our knowledge of the Neogene shark fauna and its paleobiology. Several papers deal with the large Otodus (Megaselachus) species, including the construction of a 3D model, as well as insights into its lifestyle and diet. In addition, the skeletal remains of Carcharias gustrowensis, Carcharodon hastalis, and Keasius parvus and a natural tooth set of Carcharodon hubbelli have been described in the last 13 years, and the dentition of the Neogene species Carcharoides catticus, Megachasma applegatei, and Parotodus benedenii has been reconstructed. Stable isotope analyses of the teeth from the Neogene species of Araloselachus, Carcharias, Carcharodon, Galeocerdo, Hemipristris, and Mitsukurina have given insights into the trophic positions of these genera during the Neogene, and shark teeth preserved near the skeletal remains of prey animals (mammals) and shark bite traces on these remains provide direct evidence of trophic interactions. The tooth shape, fossil locality, and paleoenvironment have been used to better understand the taxa Carcharhinus dicelmai, Megalolamna paradoxodon, Pachyscyllium dachiardii, and P. distans. Among extant species, Galeorhinus galeus can be traced back to the Eocene. Alopias superciliosus, Rhincodon typus, and possibly A. vulpinus can be traced back to the Oligocene. Species present by the Miocene include Alopias vulpinus, Carcharhinus amblyrhynchoides, C. amblyrhynchos, C. albimarginatus, C. amboinensis, C. brachyurus, C. brevipinna, C. falciformis, C. glaucus, C. leucas, C. limbatus, C. longimanus, C. macloti, C. obscurus, C. perezi, C. sealei, Centrophorus granulosus, Cetorhinus maximus, Dalatias licha, Deania calcea, Galeocerdo cuvier, Glyphis glyphis, Heptranchias perlo, Isurus paucus, Lamna nasus, Negaprion brevirostris, Odontaspis ferox, Pseudocarcharias kamoharai, Sphyrna media, S. mokarran, and possibly Carcharodon carcharias. First appearing in the Pliocene are Scymnodon ringens, Somniosus rostratus, and Zameus squamulosus. For some extant species (Carcharias taurus, Hexanchus griseus, Isurus oxyrinchus, Notorynchus cepedianus, and Sphyrna zygaena), it is not clear whether the assigned Neogene teeth represent the same species. The application of new methods to more fossil shark taxa, a detailed search for shark fossils, and better knowledge of the dentition of extant species (especially those with minute-sized teeth) will further enhance our knowledge of the evolution and paleobiology of sharks. [ABSTRACT FROM AUTHOR]

Body mass is a pivotal quantity in palaeobiology but must be inferred from an imperfect fossil record. We analyse the performance of regression models derived from various dentoskeletal predictors in mammals to inform fossils from the early, Mesozoic history of this radiation. Our focus is on the critical small end of the size spectrum; critical because the earliest mammals were small, because small size persisted onto the stems of the major extant radiations, and because small mammals compose a large proportion of crown diversity. The sampling strategy is diverse in terms of both phylogeny and skeletal predictors: the former allows a general application, while the latter enables comparison of various models. Linear regressions based on extant small mammals indicate a universal correlation of body mass with observed measurements, but with clear differences in precision. Postcranial predictors outperform jaw and dental metrics, with certain femoral joint dimensions providing surprisingly precise predictions. Our results indicate complex patterns of size evolution within the small-bodied category, including the possibility that multiple Mesozoic species approached the theoretical lower limit of mammalian body size. The ability to study such dynamics only becomes possible when predicting body mass within a strict, highly focused phylogenetic context. The heuristic value of the models we provide here is not limited to the Mesozoic but is applicable to small-bodied mammals of any geologic age. [ABSTRACT FROM AUTHOR]

Mammals (or properly, mammaliaforms) originated in the Late Triassic and the first 50 Myr of their evolution through Late Triassic and Early Jurassic are best documented by rich faunas from numerous localities around Bristol in south-west England and in South Wales. The mode of preservation of the fossils, in sediment washed into karst features such as caves, is unusual but has led to a demand for specialized processing methods to extract the exquisitely preserved tiny teeth and bones from huge volumes of sediment. This rich documentation of the oldest mammals has made them especially important for mammalian palaeobiology on a global scale. The first specimens were found in the 1860s, and collection and study has been sporadic, with especially fruitful times in the 1860s, and then from 1938–1979. Throughout, the field collecting, processing, and interpretation of the fossils has been fraught, with heated debates between leading protagonists during the second half of the past century. Here, we track the substantial contributions made by Charles Moore, Walter Kühne, Rex Parrington, Kenneth Kermack, Pamela Robinson, and others, using published sources, unpublished letters and notebooks, and interviews, to establish some of the facts about the most heated public disputes. [ABSTRACT FROM AUTHOR]

Fossil badgers of the genus Meles are known in Eurasia since the Late Pliocene but their record is utterly scarce, often represented by isolated remains. This led to taxonomic confusion and hindered phylogenetic reconstruction of the genus. Here we describe in detail all the material attributed to M. thorali from the Early Pleistocene locality of Saint-Vallier, including several new complete crania. The results of comparative morphological and morphometric analyses allow reaffirming the distinction of M. thorali from M. meles and reassessing the status of other fossil species. All the analyzed European specimens between ca 2.8 and 1.5 Ma can be reasonably accommodated in a single species, M. thorali, while in Asia the diversity is higher, with up to four taxa described. Our analyses support previous interpretations of a close relationship between M. teilhardi with M. thorali. The European Meles meles appeared around 1.5 Ma and became the only badger present in European sites. We can therefore assume that the radiation of the genus Meles occurred during the general climatic changes that took place during the latest Pliocene and the beginning of Pleistocene and resulting environmental shifts across Eurasia. [ABSTRACT FROM AUTHOR]

Retifacies abnormalis is a large artiopodan euarthropod known only from the famous fossil deposits of the Chengjiang biota, China (Cambrian Series 2, Stage 3). It is well known for its pronounced reticulated ornamentation that covers the entire dorsal surface of the exoskeleton. Here 109 new specimens of R. abnormalis from multiple deposits are reported. Some larger specimens display a distinct carapace ornamentation to what was previously known. By qualitatively separating specimens into two groups ('Morph A', 'Morph B') and analyzing the shape of the body, pygidium, and shape of the polygons in the reticulation, using linear and geometric morphometrics and elliptical Fourier analysis, the two morphs are shown to overlap in morphospace and display similar length:width ratios of body parts, rather than form two distinct clusters. The differences are interpreted as intraspecific rather than as diagnosing two species. As Morph B are only found in larger size classes, R. abnormalis ornamentation differences are interpreted to have developed during ontogeny, but are not thought to represent sexual dimorphs. [ABSTRACT FROM AUTHOR]

Reconstructions of extinct animals play an important role in vertebrate palaeontology. Such reconstructions represent visual hypotheses regarding the original morphology of the vertebrates they depict, which are amenable to future testing as additional information comes to light through discoveries of new specimens and re-examination of specimens that have already been collected. In this contribution, we argue that the scientific value of reconstructing a fossil vertebrate extends beyond simple presentation of a visual hypothesis, because the process of creating a reconstruction is itself analytical and hypothetico-deductive. Successive drafts of the reconstruction represent provisional visual hypotheses that can be tested on the basis of their internal consistency and their congruence with empirical evidence about the extinct taxon that is the reconstruction's subject. Iterative refinement of the reconstruction over successive rounds of testing and modification is likely to lead to discoveries about the subject's anatomy, as certain anatomical possibilities are rejected and others found to be plausible. These anatomical discoveries, here termed first-order inferences, may in turn lead to second-order inferences about functional morphology or other aspects of palaeobiology. Three case studies from dinosaur palaeontology, respectively involving the skull of the hadrosaurid Edmontosaurus Lambe, 1917, the forelimb of the ceratopsid Pachyrhinosaurus Sternberg, 1950, and the hindlimb of an indeterminate ceratopsid, are provided to illustrate how the process of reconstruction can be a fertile source of discoveries. [ABSTRACT FROM AUTHOR]

The fossil record demonstrates the preservation of porphyrins (e.g., heme) in organic sediments and the fossilized remains of animals. These molecules are essential components in modern metabolic processes, such as electron transport (cytochromes) and oxygen transport (hemoglobin), and likely originated before the emergence of life. The integration and adaptation of porphyrins and structurally similar molecules (e.g., chlorophylls) are key aspects in the evolution of energy production (i.e., aerobic respiration and photosynthesis) and complex life (i.e., eukaryotes and multicellularity). Here, we discuss the evolution and functional diversity of heme-bound hemoglobin proteins in vertebrates, along with the preservation of these molecules in the fossil record. By elucidating the pivotal role of these molecules in the evolution of life, this review lays the groundwork necessary to explore hemoglobin as a means to investigate the paleobiology of extinct taxa, including non-avian dinosaurs. [ABSTRACT FROM AUTHOR]

Extremes in organismal size have broad interest in ecology and evolution because organismal size dictates many traits of an organism's 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 today's 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. [ABSTRACT FROM AUTHOR]

Sphenodontians are a group of vertebrates with a vast taxonomic diversity and worldwide distribution of their fossils. Although they have been the subject of many studies on their phylogeny and morphology, those focused on their paleobiology are still scarce. We present here the osteohistology of eleven postcranial elements corresponding to a single specimen of Priosphenodon avelasi, an eilenodontine sphenodontian from Cenomanian–Turonian rocks of Río Negro (Argentina). The bone samples described here share a parallel-fibered type of matrix. The degree of vascularization varies in all the samples, but none of them present a significant density of primary vascular canals. Lines of arrested growth were observed in all appendicular elements, being better preserved in the humerus, radius and fibula. Extrinsic fibers were observed only in reduced regions of the cortex of the ulna and in one of the phalanges. The primary bone tissue suggests that the specimen had a relatively low growth rate with alternation between slow and accelerated stages. The latter could explain why this taxon reached the largest sizes of all known sphenodontians. [ABSTRACT FROM AUTHOR]

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Summary: The Ediacaran of Newfoundland preserves some of the oldest complex macroscopic communities, several of which are dominated by the fractal-like rangeomorph genus Fractofusus. Here we use computational fluid dynamics and a detailed reconstruction of Fractofusus misrai to document for the first time hydrodynamic phenomena associated with this sediment-reclining organism and its rangeomorph elements that are relevant to interpreting feeding strategies, explain the recently documented rheotropic growth oblique to currents, and provide insights into their impact on the Ediacaran seafloor. Obliquely oriented Fractofusus are common, likely representing a compromise between maximized aspect ratio and minimization of drag. Flow patterns on the upper surface of Fractofusus are consistent with the collection of dissolved and finely particulate nutrients, as well as gas exchange. Fractofusus produce a wake downstream, demonstrating that reclining rangeomorphs had potential to modify sedimentation patterns on the ancient seafloor by potentially allowing deposition of fine-grained sediment.

Summary: Wood decomposition through fungal activity is essential to the natural carbon cycle. There are three primary patterns of wood decay: white rot, brown rot, and soft rot. However, geological records of wood decay mainly originate from fossil woods, which exclusively describe white rot before the Cenozoic. Fossilized charcoal is another excellent medium for preserving pre-charring decay structures. In this study, we collected numerous charcoals from the upper Permian and observed multiple microstructures indicative of wood decay. The distinctive characteristics closely resemble the symptoms of contemporary wood-rotting types, including the removal of the middle lamella and channel-like lysis seen in white rot, shot-like holes and wavy cell walls in brown rot, and cavities within the secondary walls in soft rot. This study documents the early occurrences of multiple wood-rotting types during the Late Paleozoic and provides insights into the range of fungal metabolic strategies employed during this period.

This article presents the findings of a study on tropical paleobiology and its implications for understanding biodiversity in the past. Contrary to the prevailing belief that tropical warming reduces biodiversity, the study reveals that biodiversity during a warmer period in the past was actually higher than present-day biodiversity. The authors suggest that sampling bias and the presence of the Amazon River may have influenced these findings, and they also consider the possibility that slightly elevated temperatures during the past period promoted greater diversity. The article also discusses the potential factors contributing to the decline in species diversity in tropical marine ecosystems since the Last Interglacial (LIG) period, including the role of humans. However, the overall reduction in diversity cannot be solely attributed to human impact. The article emphasizes the need for a better understanding of historical changes and ecosystem dynamics in tropical areas to fully comprehend the dynamics of biodiversity in these regions. [Extracted from the article]

The southern Brazilian Pleistocene fauna exhibited a rich diversity of large mammalian herbivores, which are now extinct or locally extinct. In this study, we employed stable isotope analysis to investigate the past ecology of these animals. Specifically, we examined the carbonate fraction of bones and teeth and utilized compiled carbon and oxygen isotopic ratios from previous research publications. The δ13C values indicated that most specimens inhabited grassland environments, which aligns with environmental reconstructions based on pollen records of the "Campos" region. The dominant food resource for these herbivores consisted of C 3 photosynthesizers, mainly cool-season grasses. This preference can be attributed to the higher abundance and nutritional quality of cool-season grasses compared with warm-season grasses employing C 4 photosynthesis. The variability in δ18O values within and between taxa may suggest a seasonal climate. Based on these findings, we conclude that the environmental changes during the Pleistocene-Holocene transition were detrimental to the survival of these large herbivores. [ABSTRACT FROM AUTHOR]

Introduction: Modern humans are the only fully terrestrial ape. AH other apes are partially arboreal, particularly as infants and juveniles. Precocial locomotor development, high frequency of arboreal locomotion in early ontogeny, and increased terrestriality throughout development are ubiquitous amongst the hominines and likely represent the ancestral state. The role of climbing in hominin evolution has been debated for decades, but if hominins climbed regularly then subadults likely relied on it most frequently. Investigating the role of climbing throughout hominin evolution requires reliable developmentally plastic traits that are responsive to locomotor loading and can be identified in the fossil record. Chimpanzees and gorillas provide a natural experiment to examine the relationship between age-related variation locomotor activities and bone structure. Chimpanzees and gorillas are most arboreal during infancy and become more terrestrial throughout development. Gorillas are comparatively more terrestrial and transition to predominantly terrestrial locomotion at an earlier age. This paper has two main objectives. First, to examine if interspecific differences in the rate of locomotor development is reflected in bone structure. Second, to determine if ontogenetic reductions in the frequency of arboreal locomotion correspond to age-related variation in bone structure. Methods: The humerus, tibia, calcaneus, and seventh cervical vertebrae of an ontogenetic series of gorillas and chimpanzees from the Powell Cotton Museum (n = 71) were uCT scanned. Trabecular, cortical, and total bone volume fraction (BV/TV) were calculated in developmentally homologous regions of interest. Results: BV/TV scales with positive allometry throughout ontogeny. The achievement of adult-like locomotor behaviour can be identified by a significant change in the slope of Total.BV/TV with age. Younger, more arboreal individuals have relatively greater upper limb Total.BV/TV relative to the neck and lower limb than older, more terrestrial individuals in gorillas and chimpanzees. More arboreal chimpanzees have relatively more Total.BV/TV in the upper limb relative to the lower limb and neck. Discussion: The correspondence between developmental trajectories of BV/TV and locomotor ontogeny in extant apes suggests that analyses of hominin skeletal ontogeny can provide new insights into the evolution of two characteristic human traits: our slow rate of maturation and the evolution of fully terrestrial bipedalism. [ABSTRACT FROM AUTHOR]

The Early Pleistocene mammal communities of Europe are characterised by a great diversity of large carnivorans. Among them, the largest ever hyaenid, Pachycrocuta brevirostris, a fierce predator with great bone-cracking adaptations that has left its taphonomic signature on several fossiliferous sites. Here, we perform a rigorous taphonomic analysis focusing on bone surface modifications and damage patterns on large-sized ungulate bones from the site Tsiotra Vryssi (1.78 to ~1.5 Ma; Mygdonia Basin, Greece), aiming to identify the main biotic agent responsible for the modifications. Results reveal significant carnivore ravaging of the assemblage, and selective consumption of bones/bone portions related to nutrient value. Comparisons with modifications on similar-sized ungulate carcasses produced by extant and extinct predators, and similarities with Pachycrocuta-modified assemblages, indicate that Pachycrocuta was the principal agent of modification. Overall, this study not only provides taphonomic evidence for the interpretation of Tsiotra Vryssi, but also offers insights into the palaeobiology, and particularly carcass consumption behaviour of the giant hyaena. Hence, it advances our knowledge on carnivoran guild dynamics and prey– predator relationships during this epoch and has important implications for the investigations of the subsistence behaviour of the meat-eating hominins, who entered Eurasia at ~1.8 Ma, roughly synchronously with Pachycrocuta. [ABSTRACT FROM AUTHOR]

New and previously obtained paleontological data from the Vendian reference sections of the central and southwestern areas of the East European Platform are analyzed. Various associations of organic-walled microfossils and macroscopic fossil organisms of Redkino and Kotlin age are widespread in the Upper Vendian terrigenous deposits of northwestern Russia, northern Belarus, and western Ukraine. It is assumed that the Redkino and Kotlin intervals correspond to two major stages of transformation in the communities of fossil organisms. Finds of new fossils, including those representing animals, in the Upper Vendian deposits of the Kotlin Regional Stage suggest a more complex composition of the Kotlin biota than previously thought. [ABSTRACT FROM AUTHOR]