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Abstract Fossil data are subject to inherent biological, geologic, and anthropogenic filters that can distort our interpretations of ancient life and environments. The inevitable presence of incomplete fossils thus requires a holistic assessment of how to navigate the downstream effects of bias on our ability to accurately reconstruct aspects of biology in deep time. In particular, we must assess how biases affect our capacity to infer evolutionary relationships, which are essential to analyses of diversification, paleobiogeography, and biostratigraphy in Earth history. In this study, we use an established completeness metric to quantify the effects of taphonomic filters on the amount of phylogenetic information available in the fossil record of 795 extinct squamate (e.g., lizards, snakes, amphisbaenians, and mosasaurs) species spanning 242 Myr of geologic time. This study found no meaningful relationship between spatiotemporal sampling intensity and fossil record completeness. Instead, major differences in squamate fossil record completeness stem from a combination of anatomy/body size and affinities of different squamate groups to specific lithologies and depositional environments. These results reveal that naturally occurring processes create structural megabiases that filter anatomical and phylogenetic data in the squamate fossil record, while anthropogenic processes play a secondary role. 

There is currently little physics education literature examining thinking and learning in graduate education and even less literature characterizing problem solving among physics graduate students despite this being an essential professional skill for physicists. Given reports of discrepancies between physics problem solving in the undergraduate classroom and “real-world” problem solving, we sought to investigate whether this discrepancy exists at the graduate level. We first investigate the problem-solving skills present in first-year graduate physics assignments. A recent framework that characterizes problem solving as decisions-to-be-made was used. Assignments were taken from the four core courses of one academic year at one research-intensive university and coded by two researchers. We found that only 4 of the 29 decisions in the framework were present in most of the assignments. We then interviewed 11 instructors from 3 universities and asked which decisions they expected of first-year graduate students. Eleven decisions were expected by eight or more of the participants, but only four of these decisions were commonly practiced on assignments. Therefore, there seems to be a mismatch between instructor expectations and practice of problem solving on assignments. This suggests that graduate physics courses may not be aligned with the problem-solving skills that physics graduate students will need in their research or future careers. Published by the American Physical Society2025 

Monstersauria (Squamata, Anguimorpha) fossils are present in most Upper Cretaceous sedimentary basins in western North America, but despite almost a century of collection, their record remains extremely fragmentary. Here, we describe new material belonging to large-bodied monstersaurs, including a new taxon,Bolg amondolgen. et sp. nov., based on a fragmentary associated skeleton and co-occurring specimens from the middle unit of the upper Campanian Kaiparowits Formation of Grand Staircase–Escalante National Monument in southern Utah, USA. Phylogenetic analyses recoverB. amondolwithin Monstersauria, with two unique anatomical features: fused osteoderms on the jugal and the presence of autotomy septa on the distal caudal vertebrae. Critically,B. amondolis morphologically distinct from the problematic Late Cretaceous North American monstersaurPalaeosaniwa canadensis, whereas co-occurring monstersaur vertebrae and parietals from the Kaiparowits Formation (cf.P. canadensis) highlight a pressing need for a reassessment of this important, widespread taxon. These results offer new evidence that at least three lineages of distinct, large-bodied monstersaurian lizard were present on the palaeolandmass of Laramidia during the Campanian Stage. Importantly,B. amondolrepresents the most complete squamate recovered from late Campanian southern Laramidia and reveals key anatomical characteristics for future identification of isolated lizard fossil elements. 

ABSTRACT The microbial recycling of organic matter in marine sediments depends upon electron acceptors that are utilized based on availability and energetic yield. Since sulfate is the most abundant oxidant once oxygen has been depleted, the sulfide produced after sulfate reduction becomes an important electron donor for autotrophic microbes. The ability of sulfide to be re‐oxidized through multiple metabolic pathways and intermediates with variable oxidation states prompts investigation into which species are preferentially utilized and what are the factors that determine the fate of reduced sulfur species. Quantifying these sulfur intermediates in porewaters is a critical first step towards achieving a more complete understanding of the oxidative sulfur cycle, yet this has been accomplished in very few studies, none of which include oligotrophic sedimentary environments in the open ocean. Here we present profiles of porewater sulfur intermediates from sediments underlying oligotrophic regions of the ocean, which encompass about 75% of the ocean's surface and are characterized by low nutrient levels and productivity. Aiming at addressing uncertainties about if and how sulfide produced by the degradation of scarce sedimentary organic matter plays a role in carbon fixation in the sediment, we determine depth profiles of redox‐sensitive metals and sulfate isotope compositions and integrate these datasets with 16S rRNA microbial community composition data and solid‐phase sulfur concentrations. We did not find significant correlations between sulfur species or trace metals and specific sulfur cycling taxa, which suggests that microorganisms in pelagic and oxic sediments may be generalists utilizing flexible metabolisms to oxidize organic matter through different electron acceptors. 

Nearly 10% of Earth’s continents are covered by river floodplains. These landscapes serve as weathering reactors whereby particles eroded from mountains undergo chemical and physical alteration before being exported to oceans. The time a particle spends in floodplain reservoirs regulates the style and extent of continental chemical weathering and the fate of terrestrial organic carbon. Despite its importance for the global carbon cycle, we still lack a quantitative understanding of floodplain storage timescales. Using a combination of geomorphic mapping, radiocarbon and luminescence dating, and numerical simulations of meander dynamics, we identify well-conserved scaling laws that describe floodplain storage times. Our results reveal that, to first order, floodplain storage durations are set by the ratio of river width to migration rate. The fact that most rivers erode about 1% of their width per year leads to a typical floodplain storage duration of ~5 thousand years.