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In the last 50 years, the field of paleobiology has undergone a computational revolution that opened multiple new avenues for recording, storing, and analyzing vital data on the history of life on Earth. With these advances, the amount of data available for research has grown, but so too has our responsibility to ensure that our data tools and infrastructures continue to innovate in order to best serve our diverse community. This review focuses on data equity in paleobiology, an aspirational goal, wherein data in all forms are collected, stored, shared and analyzed in a responsible, equitable, and sustainable manner. While there have been many advancements across the last five decades, inequities persist. Our most significant challenges relate to several interconnected factors, including ethical data collection, sustainable infrastructure, socioeconomic biases, and global inequalities. We highlight the ways in which data equity is critical for paleobiology and stress the need for collaborative efforts across the paleobiological community to urgently address these data equity challenges. We also provide recommendations for actions from individuals, teams, academic publishers, and academic societies in order to continue enhancing data equity and ensuring an equitable and sustainable future for our field.
Combined surging and pitching of an airfoil at the identical frequency (i.e. synchronously), at four different phase differences, was investigated theoretically and experimentally. The most general unsteady theoretical formulation was adopted to calculate the lift coefficient, and then extended to explicitly compute the unsteady bound vortex sheet. This was used for comparison with experiments and facilitated the computation of both Joukowsky and impulsive-pressure lift contributions. Experiments were performed using a symmetric 18 % thick airfoil in an unsteady wind tunnel at an average Reynolds number of $3.0\times 10^5$, with a free-stream oscillation amplitude of 51 %, an angle-of-attack range of $2^\circ \pm 2^\circ$ and a reduced frequency of 0.097. In general, excellent correspondence was observed between theory and experiment, representing the first direct experimental validation of the general theory. It was shown, both theoretically and experimentally, that the lift coefficient was not accurately represented by independent superposition of surging and pitching effects, due to variations in the instantaneous effective reduced frequency not accounted for during pure pitching. Deviations from theory, observed at angle-of-attack phase leads of $90^\circ$ and $180^\circ$, were attributed to bursting of separation bubbles during the early stages of the acceleration phase. The largest deviations occurred when the impulsive-pressure lift contribution was small relative to the Joukowsky contribution, because the latter was most affected by bubble bursting. Bubble bursting resulted in large form-drag oscillations that occurred at identical phase angles within the oscillation cycle, irrespective of the phase difference between surging and pitching, as well as in the absence of pitching.
Studies on the evolution of characteristics and dynamic mechanisms of dry/wet status in global arid regions are contradictory. We systematically assessed the evolution and drivers of dry/wet status in global arid regions from a paleoclimate perspective using observational datasets, paleoclimate records, and climate model simulations from Paleoclimate Model Intercomparison Project Phase 4 (PMIP4)-Coupled Model Intercomparison Project Phase 6 (CMIP6) and PMIP3-CMIP5. Our results show that climate change during the last glacial maximum (LGM) provides a reverse analog for the near-future climate in global arid regions. The notable migration of the subtropical high during the LGM profoundly altered the atmospheric circulation and influenced dry/wet status in global arid regions. The multimodel ensembles project that under the shared socioeconomic pathway (SSP) 8.5 scenario, nonuniform heating induced by polar-amplified warming will introduce northward migration of the subtropical high. The resulting reduction in subtropical precipitation will lead to expansion of global arid regions under global warming, which is consistent with previous studies based on atmospheric aridity.
Recent archaeological studies carried out at Morro de Arica, on the Pacific coast of the south-central Andean area, traditional burial core of the Chinchorro culture (∼7000−3000 cal BP), have enabled a comparative analysis of radiocarbon dates from burial and domestic spaces, considering the differences between dated marine and terrestrial samples. Consequently, we refined the chronological sequence of the Chinchorro culture and obtained a delta reservoir effect of up to 176±113 years, allowing for interpretation of the impact of stratigraphic alterations and pottery fills on the archaeological site’s formation.
Marine flooding events occasionally interrupted the everyday lives of prehistoric coastal populations. Identification of such events are important for studies of past population dynamics and adaptive strategies. However, short-term events are rarely identified in the geological record, which puts a severe limit on our archaeological interpretive framework. This paper explores the temporality of the second Holocene transgression in southwestern Norway (ca. 3500 BCE) and works under the hypothesis that it was not a slow geological process but rather one or multiple short-term events. A Bayesian approach is used to analyze multidisciplinary time series data collected from sites located in Norway and Shetland. The resulting chronological model supports the hypothesis that the second Holocene transgression in southwestern Norway was a rapid flooding event that occurred in the period 3445–3395 BCE (Early Neolithic II). It is also suggested, but not argued conclusively, that this flooding event could correspond to the Garth tsunami, a paleotsunami named after Garth Loch in Shetland. Considering the potential impact of such a flooding event on the everyday lives of local foragers who dwelled in southwestern Norway, it is anticipated that this study could form a starting point for future case studies.
Although octopuses are the third most fished marine invertebrate species in Puerto Rico, there is a lack of information about this fishery. Here, we present the first small-scale study assessing the genetic diversity and connectivity of Octopus vulgaris in Puerto Rico. To achieve this, we applied double-digest restriction-site associated DNA sequencing, using the restriction enzymes EcoRI and SphI in 43 specimens captured from ten locations representing three geographic regions. We used F-statistics and Bayesian analysis to evaluate over 2000 polymorphic loci. We found high genetic connectivity (FST = 0.0008, FST = 0.005), high nucleotide diversity (π ≈ 0.1), and moderate genetic diversity (HO ≈ 0.255–0.361, HE ≈ 0.258–0.373) between the studied regions. In contrast to our expectations, given oceanographic characteristics and distance between the geographic regions, our results suggest a single admixed population of O. vulgaris in Puerto Rico, with no differentiation between the sampled regions. Even though genomics techniques are powerful for inferring population connectivity, researchers should be cognizant of protocol limitations to retain the most reliable information possible.
A model for groundwater silicification within the Sables de Fontainebleau in sub-contemporary landscapes in the Paris Basin proposed 35 years ago has since been continuously and substantially updated, particularly with reference to new studies that relate silica precipitation to periglacial climate conditions. Herein we link the various distinctive morphologies of silicified sandstone bodies to the flow paths of groundwaters that imported the silica, the conditions under which it was precipitated, and the patterns of iced ground. The silicified masses are, in a way, fossil groundwater flow paths. The spatial arrangements of these paleo-groundwater flow paths suggest that permafrost developed to significant depth in parts of the Paris Basin. Our model visualizes a gradual settlement of periglacial conditions in the landscape starting with (1) cooling of the near-surface regolith and development of horizontal silicified pans; (2) progressive descent of impermeable permafrost as glacial conditions persisted, leading to non-horizontal flows ‘forced’ beneath the frozen layer; (3) thickening of the permafrost and consequent pressurization of groundwater in the phreatic zone when groundwater outflows to the valleys froze and closed, and convoluted silicified masses and possibly vertical dikes were formed; (4) followed by later thawing of the permafrost and a reduction in hydrostatic level due to climate warming leading to growth of geotropic silicified bodies when residual permafrost remained at depth. In this context, the distinctive morphologies of the silicified sand masses are proxies for the paleohydrology that prevailed during silicification and constitute a new toolbox for determining the depths reached by permafrost at time of silicification.
Incorporating paleontological data into phylogenetic inference can greatly enrich our understanding of evolutionary relationships by providing insights into the diversity and morphological evolution of a clade over geological timescales. Phylogenetic analysis of fossil data has been significantly aided by the introduction of the fossilized birth–death (FBD) process, a model that accounts for fossil sampling through time. A decade on from the first implementation of the FBD model, we explore its use in more than 170 empirical studies, summarizing insights gained through its application. We identify a number of challenges in applying the model in practice: it requires a working knowledge of paleontological data and their complex properties, Bayesian phylogenetics, and the mechanics of evolutionary models. To address some of these difficulties, we provide an introduction to the Bayesian phylogenetic framework, discuss important aspects of paleontological data, and finally describe the assumptions of the models used in paleobiology. We also present a number of exemplar empirical studies that have used the FBD model in different ways. Through this review, we aim to provide clarity on how paleontological data can best be used in phylogenetic inference. We hope to encourage communication between model developers and empirical researchers, with the ultimate goal of developing models that better reflect the data we have and the processes that generated them.
Paleobiology was founded 50 years ago to provide an outlet for biological paleontology, with an emphasis on investigating evolutionary patterns and processes that could apply generally across the history of life. While the intellectual and financial prospects for Paleobiology were uncertain in the beginning (Sepkoski 2012; Valentine 2009), this 50th anniversary issue testifies to its overwhelming success. Fifty years of anything well done deserves a celebration. These moments are a time for reflection and a time for imagining future directions. With this introduction, we outline briefly the start of the journal and two landmark anniversary issues, the 10th and the 25th. No special issue can adequately survey all research themes in a field as intellectually rich as paleobiology. However, these anniversary issues offer a snapshot of research directions, and they can trace the shift and expansion of established fields and mark the emergence of new ones. We end by outlining the contributions to the 50th anniversary issue that summarize current themes and future directions for the field.
The orientational trajectories of rod-like particles suspended in a liquid are influenced by their surroundings, such as the type of flow and nearby walls, and deviate from the well-known Jeffery orbits in shear flows. We consider two types of shear flows between two parallel planar walls: wall-driven simple shear flow (C-flow), and parabolic flow driven by an external body force (P-flow). We simulated hydrodynamically interacting rod-like particles using a chain-of-spheres model immersed in a lattice Boltzmann fluid within a confined channel. As these particles in shear flows approach the wall, their orbits become flattened, exhibiting a ‘swinging motion’ on a plane parallel to the wall. Near the wall, the influence of the wall on the orbital motion varies depending on the flow type. In P-flow, the particles maintain their periodic swinging motions, whereas in C-flow, they stop swinging and align with the flow direction. This difference arises due to distinct hydrodynamic interactions with the wall in each flow type. Simulations also replicated the ‘pole-vaulting’ motion, where particles move away from the wall during their tumbling motion. For weakly sedimenting particles under shear flows, both flow types showed behaviour similar to that of neutrally buoyant particles. However, in P-flow, driven by gravity towards the wall, the particles cease their swinging motion and align perpendicularly to the flow direction, consistent with experimental observations.
Polychaetes (Phylum Annelida) respond to sensory stimuli through the usage of sensory organs and appendages, such as palps, which vary in shape and structure depending on lifestyle. The typical palps of nereidid polychaetes are tapered appendages constituted by two articles. The palpophore is the wider and longer basal article, followed by the thinner and shorter palpostyle that contains the majority of sensory cells. Previous studies on Hediste diversicolor palps were focused on these sensory cells. To achieve a more comprehensive view of the histology and ultrastructure of the palps, H. diversicolor specimens were collected from the northern Portuguese Atlantic coast and the palps were processes for light (semithin sections) and transmission electron microscopy. The current study revealed details of the cuticle, which is thinner in the palpostyle than in the palpophore. Five types of secretory cells were distinguished mainly based on the characteristics of their secretory vesicles. Two of these types could be classified as protein-secreting cells, and the other three as mucus-secreting cells. Granulocytes and eleocytes were found in the celom cavity of the palps. The latter contained lipid droplets and a very large amount of glycogen. In the central region of the palpophore, a ring of muscle cells responsible for the retraction of the palpostyle encircled the main palp nerve. The latter was formed by numerous axons and glial cells containing bundles of filaments and gliosomes.
A new genus is established for species of late Paleozoic pterioid bivalves that have substantial ontogenetic change in hinge characters during growth. Juvenile shells have small cardinal and posterior lateral teeth on the hinge that are overgrown on the adult shell and the hinge become edentulous. The shell has a wide ligament plate with a clinovincular ligament (new term). Adjacent to the cardinal teeth on juvenile shell, ligament sheets tend to have small, low amplitude folding and wavy alignment of ligament grooves. A new genus and species, Willipteria nestelli, is described and the species Leptodesma falcata Boyd and Newell, is transferred to genus Willipteria n. gen. Comparison of Willipteria n. gen. to Leptodesma reveals a need to revise Leptodesma. A study of the type lot of genotype species Leptodesma potens Hall, provides a redescription for the genus, presented here. Definition of the new term, clinovincular ligament, is presented. Discussion of muti-sheet ligaments is presented for duplivincular, monovincular, and clinovincular configurations.
Peat is formed by the accumulation of organic material in water-saturated soils. Drainage of peatlands and peat extraction contribute to carbon emissions and biodiversity loss. Most peat extracted for commercial purposes is used for energy production or as a growing substrate. Many countries aim to reduce peat usage but this requires tools to detect its presence in substrates. We propose a decision support system based on deep learning to detect peat-specific testate amoeba in microscopy images. We identified six taxa that are peat-specific and frequent in European peatlands. The shells of two taxa (Archerella sp. and Amphitrema sp.) were well preserved in commercial substrate and can serve as indicators of peat presence. Images from surface and commercial samples were combined into a training set. A separate test set exclusively from commercial substrates was also defined. Both datasets were annotated and YOLOv8 models were trained to detect the shells. An ensemble of eight models was included in the decision support system. Test set performance (average precision) reached values above 0.8 for Archerella sp. and above 0.7 for Amphitrema sp. The system processes thousands of images within minutes and returns a concise list of crops of the most relevant shells. This allows a human operator to quickly make a final decision regarding peat presence. Our method enables the monitoring of peat presence in commercial substrates. It could be extended by including more species for applications in restoration ecology and paleoecology.
The reduction of the hydrodynamic forces exerted on a bluff body in an incoming flow has been an issue of interest in fluid mechanics for many years. However, the Magnus effect indicates possible drag reduction but with the lift being increased significantly. This study is aimed at the simultaneous lift and drag reduction for which we consider a constant incoming flow past a circular cylinder or a sphere in the $x$-direction. Force element analysis (FEA) indicates the possibility of reducing the drag exerted on a circular cylinder or a sphere by rotating (say, clockwise about the $z$-axis) only the front half of the circular cylinder or the sphere. More precisely, we rotate the object but with the rear half covered by a closely spaced hood. Numerical simulations show that by increasing the dimensionless rotational speed $\alpha$: (i) the flow can be quickly stabilised to a steady state; (ii) the mean drag steadily decreases to zero and then becomes negative as $\alpha$ is further increased across the critical $\alpha _I = 4.11$ for the circular cylinder at $Re$ = 200, $\alpha _I = 4.81$ for the sphere at $Re$ = 200 and $\alpha _I = 4.92$ for the sphere at $Re$ = 300; (iii) the mean value of the lift decreases from zero to negative and then increases beyond zero, and in addition, the amplitude of the lift gradually decreases for the circular cylinder; the mean value of the lift decreases from zero to negative for the sphere; (iv) the side force is almost zero – the flow over the sphere is plane-symmetric about the $x{-}y$ plane. These features are compared with the flow past a rotating circular cylinder or a rotating sphere (Magnus effect). Notably, there is a range of flows that can be of practical use for: (a) the circular cylinder where the drag is greatly reduced while the lift is small in magnitude and (b) the sphere where the drag is greatly reduced while the lift is negative in magnitude and the side force is close to 0.
Despite the importance of the commercially harvested benthopelagic fish Beryx mollis, little information is available on their adult phase and reproduction. This is likely due to the low abundance of this species compared to Beryx splendens and Beryx decadactylus as well as misidentification of Beryx spp. In this study, early life stages of B. mollis were found in the southwest region off Sri Lanka during a survey with research vessel Dr Fridtjof Nansen in 2018, coinciding with the southwest monsoon period. As morphological characteristics of eggs and larval stages of the three Beryx spp. are very similar, visual identification to differentiate to species level has always been challenging. Therefore, in this study, DNA barcoding was carried out targeting the mitochondrial COI gene. Molecular analysis confirmed that the collected egg and larvae belonged to the B. mollis species due to their high identity (>99%) with reference to previously submitted adult B. mollis sequences in the GenBank. Phylogenetic analysis showed a closer evolutionary relationship among B. mollis and B. splendens than with B. decadactylus. To the best of our knowledge this is the first genetic and morphological confirmation of B. mollis egg and larvae worldwide and suggests the southwest coastal area in Sri Lanka, in the north central Indian Ocean, as a potential spawning ground for this species.
We examined a zooarchaeological assemblage from Badger Island, a 12.4 km2 landbridge island in the Furneaux Group, Bass Strait, south-eastern Australia. The accumulation consisted of Pleistocene and Holocene strata that were rich in mammal remains. Small mammal remains were accumulated by owls, whereas large mammal remains were accumulated by people and/or autochthonous mortality. The Pleistocene fauna was dominated by grassland mammals, particularly Mastacomys fuscus (Broad-toothed Rat), but these gradually declined and were largely replaced by forest–woodland dwelling mammals in the Holocene. The same pattern of faunal change has been observed on the large main island of Tasmania (∼65,000 km2), suggesting changes observed at Beeton Rockshelter are representative of the region. Because all of the Furneaux Group Islands were united as one landmass in the past, the fossil fauna observed in Beeton Rockshelter is relevant to conservation-oriented mammal-restoration initiatives, which are being considered throughout the entire Furneaux Group.
Increasing penetration of variable and intermittent renewable energy resources on the energy grid poses a challenge for reliable and efficient grid operation, necessitating the development of algorithms that are robust to this uncertainty. However, standard algorithms incorporating uncertainty for generation dispatch are computationally intractable when costs are nonconvex, and machine learning-based approaches lack worst-case guarantees on their performance. In this work, we propose a learning-augmented algorithm, RobustML, that exploits the good average-case performance of a machine-learned algorithm for minimizing dispatch and ramping costs of dispatchable generation resources while providing provable worst-case guarantees on cost. We evaluate the algorithm on a realistic model of a combined cycle cogeneration plant, where it exhibits robustness to distribution shift while enabling improved efficiency as renewables penetration increases.
As climate change intensifies, conflict-prone tropical regions face heightened vulnerabilities, yet little is known about how climate adaptation and food security efforts affect conflict dynamics. Using South Sudan – a country highly susceptible to climate stress and conflict – as a test case, this Element analyzes how international nongovernmental organizations' (INGO) climate adaptation interventions influence civil war and local social conflicts. It develops a theoretical framework linking climate adaptation to conflict, positing both positive and negative externalities. Drawing on original high-resolution data on INGO-driven adaptation and food security efforts, alongside climate, conflict, and development data, findings are substantiated with interviews from policy workers in South Sudan. The results indicate that while adaptation generally does not reduce conflict, interventions that promote preparedness and are implemented during periods of high climate stress can mitigate social conflicts between militias, pastoralists, and farmers. These insights provide guidance for designing climate adaptation strategies that reduce conflict risks.