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Abstract Palaeontological field surveys in remote regions are a challenge, because of uncertainty in finding new specimens, high transportation costs, risks for the crew and a long time commitment. The effort can be facilitated by using high-resolution satellite imagery. Here we present a new opportunity to investigate remote fossil localities in detail, mapping the optical signature of individual fossils. We explain a practical workflow for detecting fossils using remote-sensing platforms and cluster algorithms. We tested the method within the Petrified Forest National Park, where fossil logs are sparse in a large area with mixed lithologies. We ran both unsupervised and supervised classifications, obtaining the best estimations for the presence of fossil logs using the likelihood and spectral angle mapper algorithms. We recognized general constraints and described logical and physical pros and cons of each estimated map. We also explained how the outcomes should be critically evaluated with consistent accuracy tests. Instead of searching for fossiliferous outcrops, our method targets single fossil specimens (or highly condensed accumulations), obtaining a significant increase in potential efficiency and effectiveness of field surveys. When repeatedly applied to the same region over time, it could also be useful for monitoring palaeontological heritage localities. Most importantly, the method here described is feasible, easily applicable to both fossil logs and bones, and represents a step towards standard best practices for applying remote sensing in the palaeontological field. 

Abstract AimWe investigate geographic patterns across taxonomic, ecological and phylogenetic diversity to test for spatial (in)congruency and identify aggregate diversity hotspots in relationship to present land use and future climate. Simulating extinctions of imperilled species, we demonstrate where losses across diversity dimensions and geography are predicted. LocationNorth America. Time periodPresent day, future. Major taxa studiedRodentia. MethodsUsing geographic range maps for rodent species, we quantified spatial patterns for 11 dimensions of diversity: taxonomic (species, range weighted), ecological (body size, diet and habitat), phylogenetic (mean, variance, and nearest‐neighbour patristic distances, phylogenetic distance and genus‐to‐species ratio) and phyloendemism. We tested for correlations across dimensions and used spatial residual analyses to illustrate regions of pronounced diversity. We aggregated diversity hotspots in relationship to predictions of land‐use and climate change and recalculated metrics following extinctions of IUCN‐listed imperilled species. ResultsTopographically complex western North America hosts high diversity across multiple dimensions: phyloendemism and ecological diversity exceed predictions based on taxonomic richness, and phylogenetic variance patterns indicate steep gradients in phylogenetic turnover. An aggregate diversity hotspot emerges in the west, whereas spatial incongruence exists across diversity dimensions at the continental scale. Notably, phylogenetic metrics are uncorrelated with ecological diversity. Diversity hotspots overlap with land‐use and climate change, and extinctions predicted by IUCN status are unevenly distributed across space, phylogeny or ecological groups. Main conclusionsComparison of taxonomic, ecological and phylogenetic diversity patterns for North American rodents clearly shows the multifaceted nature of biodiversity. Testing for geographic patterns and (in)congruency across dimensions of diversity facilitates investigation into underlying ecological and evolutionary processes. The geographic scope of this analysis suggests that several explicit regional challenges face North American rodent fauna in the future. Simultaneous consideration of multi‐dimensional biodiversity allows us to assess what critical functions or evolutionary history we might lose with future extinctions and maximize the potential of our conservation efforts. 

Landscape properties have a profound influence on the diversity and distribution of biota, with present-day biodiversity hot spots occurring in topographically complex regions globally. Complex topography is created by tectonic processes and further shaped by interactions between climate and land-surface processes. These processes enrich diversity at the regional scale by promoting speciation and accommodating increased species richness along strong environmental gradients. Synthesis of the mammalian fossil record and a geophysical model of topographic evolution of the Basin and Range Province in western North America enable us to directly quantify relationships between mammal diversity and landscape dynamics over the past 30 million years. We analyze the covariation between tectonic history (extensional strain rates, paleotopography, and ruggedness), global temperature, and diversity dynamics. Mammal species richness and turnover exhibit stronger responses to rates of change in landscape properties than to the specific properties themselves, with peaks in diversity coinciding with high tectonic strain rates and large changes in elevation across spatial scales. 

Mammals rose to prominence in terrestrial ecosystems after the Cretaceous–Paleogene mass extinction, but the mammalian lineages characteristic of Paleogene faunas began their evolutionary and ecological diversification in the Late Cretaceous, stimulated by the rise of angiosperms (flowering plants) according to the preeminent hy- pothesis. The Cretaceous rise of mammals is part of a larger expansion in biodiversity on land that has been termed the Cretaceous (or Angiosperm) Terrestrial Revolution, but the mechanisms underlying its initiation remain opaque. Here, we review data from the fossil and rock records of western North America—due to its relatively continuous fossil record and complete chronology of mountain-building events—to explore the role that tectonism might have played in catalyzing the rise of modern-aspect terrestrial biodiversity, especially that of mammals and angiosperms. We highlight that accelerated increases in mammal and angiosperm species richness in the Late Cretaceous, ca. 100–75 Ma, track the acceleration of tectonic processes that formed the North American Cordillera and occurred during the ‘middle-Cretaceous greenhouse’ climate. This rapid increase in both mammal and angiosperm diversity also occurred during the zenith of Western Interior Seaway trans- gression, a period when the availability of lowland habitats was at its minimum, and oscillatory transgression- regression cycles would have frequently forced upland range shifts among lowland populations. These changes to both landscapes and climates have all been linked to an abrupt, global tectonic-plate ‘reorganization’ that occurred ca. 100 Ma. That mammals and angiosperms both increased in species richness during this interval does not appear to be a taphonomic artifact—some of the largest spikes in diversity occur when the available mammal-bearing fossil localities are sparse. Noting that mountainous regions are engines for generating biodi- versity, especially in warm climates, we propose that the Cretaceous/Angiosperm Terrestrial Revolution was ultimately catalyzed by accelerated tectonism and enhanced via cascading changes to landscapes and climate. In the fossil record of individual basins across western North America, we predict that (1) increases in mammalian diversity through the Late Cretaceous should be positively correlated with rates of tectonic uplift, which we infer to be a proxy for topographic relief, and are attended by increased climate heterogeneity, (2) the diversity of mountain-proximal mammalian assemblages should exceed that of coeval mountain-distal assemblages, espe- cially in the latest Cretaceous, and (3) endemism should increase from the latest Cretaceous to early Paleogene as Laramide mountain belts fragmented the Western Interior. Empirical tests of these predictions will require increased fossil collecting in under-sampled regions and time intervals, description and systematic study of existing collections, and basin-scale integration of geological and paleontological data. Testing these predictions will further our understanding of the coevolutionary processes linking tectonics, climate, and life throughout Earth history. 

Tectonic processes drive the evolution of basins through local and regional changes in topographic relief, which have long-term effects on mammalian richness and distribution. Mammals respond to the resulting changes in landscape and climate through evolution, shifts in geographic range, and by altering their community composition. Here, we evaluate the relationship between tectonic episodes and the diversification history of fossil mammals in the Miocene Dove Spring Formation (12.5−8.5 Ma) of southern California, USA. This formation contains a rich fossil record of mammals and other vertebrates as well as structural and sedimentological evidence for tectonic episodes of basin extension, rotation, and translation. We used several methods to compare the fossil record to the tectonic history of the Dove Spring Formation. We updated the formation’s geochronology to incorporate current radiometric dating standards and measured additional stratigraphic sections to refine the temporal resolution of large mammal (>1 kg) fossil localities to 200-kyr (or shorter) intervals. Observed species richness over time follows the same trend as the number of localities and specimens, suggesting that richness reflects sampling intensity. Estimates of stratigraphic ranges with 80% confidence intervals were used to conduct per capita diversification analysis and a likelihood approach to changes in faunal composition from one time interval to the next. While edge effects influence time bins at the beginning and end of the study interval, we found changes in diversification rates and faunal composition that are not solely linked to preservation. Several rare species appear at 10.5 Ma and persist through the top of the formation despite variable preservation rates. Changes in faunal composition at 12.1 Ma and 10.5 Ma are not associated with elevated preservation rates, which indicates that some faunal changes are not primarily driven by sampling effort. The lower portion of the formation is characterized by high origination rates and long residence times. The upper portion has high per capita extinction rates that increased in magnitude as basin rotation and translation progressed from 10.5 Ma. The greatest change in faunal composition coincided with basin rotation and translation that interrupted a long-running extensional period. Tectonics played key roles in the diversity of mammals by determining fossil productivity and shaping the landscapes that they inhabited. 

Darwin Core, the data standard used for sharing modern biodiversity and paleodiversity occurrence records, has previously lacked proper mechanisms for reporting what is known about the estimated age range of specimens from deep time. This has led to data providers putting these data in fields where they cannot easily be found by users, which impedes the reuse and improvement of these data by other researchers. Here we describe the development of the Chronometric Age Extension to Darwin Core, a ratified, community-developed extension that enables the reporting of ages of specimens from deeper time and the evidence supporting these estimates. The extension standardizes reporting about the methods or assays used to determine an age and other critical information like uncertainty. It gives data providers flexibility about the level of detail reported, focusing on the minimum information needed for reuse while still allowing for significant detail if providers have it. Providing a standardized format for reporting these data will make them easier to find and search and enable researchers to pinpoint specimens of interest for data improvement or accumulate more data for broad temporal studies. The Chronometric Age Extension was also the first community-managed vocabulary to undergo the new Biodiversity Informatics Standards (TDWG) review and ratification process, thus providing a blueprint for future Darwin Core extension development. 

Studies of horse evolution arose during the middle of the 19th century, and several hypotheses have been proposed for their taxonomy, paleobiogeography, paleoecology and evolution. The present contribution represents a collaboration of 19 multinational experts with the goal of providing an updated summary of Pliocene and Pleistocene North, Central and South American, Eurasian and African horses. At the present time, we recognize 114 valid species across these continents, plus 4 North African species in need of further investigation. Our biochronology and biogeography sections integrate Equinae taxonomic records with their chronologic and geographic ranges recognizing regional biochronologic frameworks. The paleoecology section provides insights into paleobotany and diet utilizing both the mesowear and light microscopic methods, along with calculation of body masses. We provide a temporal sequence of maps that render paleoclimatic conditions across these continents integrated with Equinae occurrences. These records reveal a succession of extinctions of primitive lineages and the rise and diversification of more modern taxa. Two recent morphological-based cladistic analyses are presented here as competing hypotheses, with reference to molecular-based phylogenies. Our contribution represents a state-of-the art understanding of Plio-Pleistocene Equus evolution, their biochronologic and biogeographic background and paleoecological and paleoclimatic contexts. 

The Barstow Formation in the Mojave region of California was deposited in an extensional-basin setting of the Basin and Range province and preserves diverse middle Miocene mammalian assemblages. Six facies associations represent the dominant depositional environments in the basin, which changed through time from alluvial-fan and playa-dominated settings to floodplains and spring-fed wetlands. The majority of fossil localities and specimens occur in later-forming facies associations. We analyzed the taphonomic characteristics of fossil assemblages to test whether basin-scale facies associations or locality-scale facies exert more control on the preservational features of mammalian assemblages through the formation. We documented the facies settings of 47 vertebrate localities in the field in order to interpret depositional setting and the mode of accumulation for fossil assemblages. We evaluated skeletal material in museum collections for taphonomic indicators, including weathering stage, original bone-damage patterns, hydraulic equivalence, and skeletal-element composition. We evaluated four alternative modes of accumulation, including attritional accumulation on the land surface, accumulation by fluvial processes, carnivore or scavenger accumulations, and mass-death events. The majority of localities represent attritional accumulations at sites of long-term mortality in channel-margin, abandoned-channel, poorly drained floodplain, and ephemeral-wetland settings. Skeletal-element composition and taphonomic characteristics varied among facies, indicating an important role for depositional setting and landscape position on fossil-assemblage preservation. We find that locality-scale facies have a greater influence on the taphonomic characteristics of fossil assemblages; the taphonomy of each facies association is influenced by the facies that compose it. The facies composition and distribution within facies associations change through the formation, with a greater variety of depositional settings forming later in the history of the basin. Heterogeneous landscapes present more settings for fossil accumulation, contributing to the increase in fossil occurrence through the depositional history of the formation.