Royal Society Open Science

Purpose: Impaired balance and fall risk in individuals with respiratory conditions highlight the importance of respiratory-postural integration during upright activity. However, breathing and postural control are often studied separately, limiting understanding of their interaction. Singing imposes concurrent ventilatory and trunk control demands, yet respiratory-postural responses during standing singing remain unclear. We examined the effects of vocalisation and tempo on respiratory-postural responses during standing, and whether age and singing experience moderated these responses. Methods: Eighty healthy younger (18-35yr; n=35) and older ([&ge;]60yr; n= 45) adults completed rhythmically paced speaking and singing tasks at slow, normal, and fast tempos while standing on a force platform. Respiratory rate (RR), mediolateral and anteroposterior sway, peripheral oxygen saturation, and perceived breathlessness were measured. Generalised estimating equations assessed vocalisation, tempo, and their interaction, with moderation by age and singing experience. Results: RR showed a vocalisation x tempo interaction (p<.001), with higher RR during slow speaking and greatest increases during fast singing. Singing increased postural sway relative to speaking, particularly mediolaterally (p<.001), with tempo-related increases in anteroposterior sway (p<.001). Older adults exhibited greater postural sway overall (p values[&le;].040) but similar task-dependent modulation to younger adults. Singing experience attenuated RR increases during fast singing (p=.033) and was associated with greater mediolateral sway (p=.004). Perceived breathlessness increased with tempo but was not associated with vocalisation; SpO2 was unchanged. Conclusions: Standing singing was associated with tempo-dependent respiratory and postural responses. Age and singing experience showed distinct associations with these responses. Task-dependent respiratory-postural coordination appeared preserved among participants.

Despite their currently scarce taxonomic diversity, rhinocerotoids were among the most evolutionarily successful clades of large herbivorous mammals throughout the Caenozoic. Within an array of morphological adaptations, the cranial horn represents the clades most remarkable and name-giving feature, imposing significant morpho-functional demands on the skull. In this paper, patterns and drivers of the rhinos cranial evolution were investigated for the first time by compiling a three-dimensional geometric morphometric dataset of living and extinct species. Multiple aspects of morphological evolution were explored using phylogenetic comparative methods, including craniofacial evolutionary allometry (CREA - tendency of larger species to have longer faces), phylogenetic constraints, and tempo of evolution. Cranial shape variation linked to horn presence and size evolved under a phylogenetically constrained framework, with a notable transition from hornless to horned species. Rhinos significantly deviated from CREA, likely due to diversity of cranial forms and proportions that evolved independently across the clade in response to varying horn morphologies and dietary habits. Hornless and horned rhinos exhibited similar rates of cranial evolution, and shape variation was obtained through multiple episodes of accelerated evolution. This highlights the role of morphological innovations and Caenozoic global cooling events in the emergence of phenotypic diversity.

Eponymous etymologies (i.e., organisms named after people) are prevalent in global taxonomy worldwide, across scientific and common names. The persistent usage of eponyms has been intensely debated in recent times, across various sociopolitical, applied and philosophical perspectives. However, a rigorous statistical analysis of eponyms and their enduring colonial legacies remains hitherto unexplored. Here, we use a global and spatially-explicit network analysis to examine 2416 contemporary bird eponyms (21% of all bird species on earth) and their relationships with historical European colonialism. Additionally, we develop and utilise a Colonial Exposure Index (CEI) that summarizes the geopolitical influence of various colonial empires on modern-day countries. Our results show that an overwhelming majority of bird eponyms worldwide are named after people belonging to countries where the bird species does not occur. A majority of these eponyms honor scientists, aristocrats and army officers from erstwhile colonial empires, with eponymous species descriptions peaking during colonial expansion. Importantly, our analysis highlights a positive relationship between the Colonial Exposure Index (a metric factoring the duration and area of a country colonized by a specific empire) and the number of eponymous bird species honoring persons from that specific empire. Our temporal analysis, however, shows that the use of eponyms has recently shifted towards honoring native persons and distinguished conservation champions. Overall, this study presents an important statistical examination of eponyms and their colonial legacies, thereby providing valuable context for ongoing debates on the reform or retention of eponyms worldwide.

Tessellated calcified cartilage (TCC) is a hallmark of the chondrichthyan skeleton, yet its development early in ontogeny across the four major groups (batoids, galeomorphs, squalomorphs, and holocephalans) remains poorly understood. Specialised traits of TCC, such as multi-layered TCC and internal mineralised trabeculae, typically develop in response to feeding mechanics. In this study, we evaluated TCC morphology in the jaws of 12 representative taxa to observe its structure at an early ontogenetic stage to determine whether these specialised features had yet developed. Batoids consistently exhibited well-developed, homogeneous, polygonal tesserae early in ontogeny regardless of jaw morphology or feeding habit. In contrast, galeomorphs displayed high morphological heterogeneity. Notably, we document the first report of an extensive internal trabecular network in a non-batoid elasmobranch, observed in Ginglymostoma cirratum, which may serve to resist the mechanical pressures of specialised suction feeding. Furthermore, we identified voussoir tesserae in galeomorphs for the first time, extending their documented presence across all elasmobranch groups, where they display an inverted aspect ratio (wider than tall) compared to mature forms. The durophagous Mustelus mustelus exhibited surprisingly poor TCC development despite being a durophagous feeder, pointing to a pronounced ontogenetic lag. In Squatina oculata, TCC was characterised by large and thick tesserae and extensive fused tesseral regions which may relate to its explosive ambush predation mode, whereas the holocephalan Chimaera exhibited a poorly mineralized, mesh-like structure without resolvable discrete tesserae or trabeculae-matching findings from previous studies. Across all specimens, multi-layered TCC was absent, confirming that multi-layering develops later in ontogeny. These results demonstrate that generalised models of TCC development based on one group or a few taxa fail to capture the broader diversity of TCC morphology. It also opens up many exciting avenues for further study, and forms the basis for comparisons with fossil chondrichthyans, to investigate the evolution of TCC.

The initial response of populations to the SARS-CoV-2 virus reduced the incidence of COVID-19 cases. However, this success was shorted lived once most populations relaxed most restrictions, resulting in an increase in infections. This feedback contributed to additional pandemic waves. The temporal unfolding of behavioural changes in populations present a challenge to mathematical models for disease dynamics. Coupled behaviour-disease models with varying levels of complexity accounting for several factors have been used to capture behavioural dynamics and SARS-CoV-2 transmission, with varying results. To study the impact of model complexity on the predictive power of models, here we formulate five coupled behaviour-disease models with varying structure and number of parameters. We fit the models to SARS-CoV-2 infection incidence and stringency of control interventions from five European countries in the first wave, and study how well these fitted models predict the second wave. We show that models with more parameters do not necessarily have a greater ability to explain and predict key features of a pandemic wave. Hence, our results show that a relatively simple coupled behaviour-disease model with important parameters can do an adequate job of providing information about the pandemic wave. Additionally, our findings show that complex models can be country-specific, working better for some countries and poorly for others. We conclude that modellers should not always opt for the most complicated possible models, if the data do not support their use.

A high proportion of the world's population relies on marine fisheries as a source of food and employment, highlighting the need for sustainable exploitation strategies. However, fisheries management commonly relies on single-species models that overlook ecological interactions and economic trade-offs, which may lead to stocks being exploited above sustainable levels. To address this gap, we developed a novel size-structured, multispecies bioeconomic module integrated within the spatially explicit, individual-based OSMOSE ecosystem model. OSMOSE represents exploited fish communities in which individuals interact through opportunistic, size-dependent predator-prey interactions which are explicitly incorporated into the bioeconomic framework. The bioeconomic model accounts for multiple species and size classes, allowing for size-dependent market prices. Fishing costs and profits are represented using an extension of the Gordon-Schaefer model to multiple interacting species, while consumer demand is modelled using a nested Dixit-Stiglitz utility function with three levels of constant elasticity of substitution for fish commodity, species and size classes. We present a method for estimating parameters for the bioeconomic module when empirical estimates are unavailable, using the North Sea OSMOSE configuration, which comprises 15 species. Our method successfully estimated the six bioeconomic parameters required to operationalise the model. Results indicate that differences in cost parameters were primarily associated with variability in species biomass rather than fishing gear, while fish prices were more strongly influenced by consumer's demand than by availability. This framework provides a basis for assessing the economic consequences of alternative climate change scenarios and supporting sustainable fisheries management.

The energetic cost of building human skeletal muscle has never been explicitly calculated or measured. We developed a quantitative bottom-up accounting model that integrates human skeletal-muscle composition with empirically informed estimates of tissue synthesis, physiological deposition, maintenance during accretion, and diet-induced thermogenesis. The calculation was expressed per kg of wet skeletal muscle and organized into five additive components: stored tissue energy, biochemical synthesis cost, physiological deposition cost, resting maintenance during accretion, and diet-induced thermogenesis. Stored tissue energy was approximately 5670 kJ/kg (1355 kcal/kg). Adding biochemical synthesis cost gave 6340 kJ/kg (1515 kcal/kg). Applying empirically derived deposition-efficiency parameters yielded a physiological deposition requirement of 9780 to 11690 kJ/kg (2338 to 2793 kcal/kg), centrally 10830 kJ/kg (2587 kcal/kg). Adding resting maintenance during accretion and diet-induced thermogenesis produced a final additional metabolizable energy intake of 13410 to 15520 kJ/kg (3204 to 3710 kcal/kg), centrally 14570 kJ/kg (3481 kcal/kg). This value provides a first quantitative reference estimate for the energetic cost of human skeletal-muscle accretion.

This research addresses a central question in Palaeolithic research: how hunter-gatherer mobility was structured across space and time in the Cantabrian Region (northern Iberia), which has human occupation evidence spanning from the Middle Pleistocene through the Holocene. A multidisciplinary framework integrating primarily {delta}3S isotope values, combined with {delta}{superscript 1}3C and {delta}{superscript 1}N, palaeoproteomics, Bayesian age modelling, palaeoclimatic reconstruction, isoscape mapping, and ecological diversity was developed. A total of 905 animal bone collagen samples, with evidence of anthropogenic modifications, from 16 key archaeological sites from the Mousterian to Mesolithic (Marine Isotopic Stage 5 to 1, between 100-7 ka BP) were analysed, permitting the reconstruction of spatial patterns of resource exploitation and human mobility. The {delta}3S isotope values show weak, inconsistent relationships with climatic proxies, suggesting that sulfur signatures are primarily driven by geographic and ecological factors rather than climate. Strong spatial trends are observed, with higher {delta}3S values in coastal zones and lower values inland. Diachronic trends reveal marked shifts in human mobility: smaller ranges during the Mousterian, increasing mobility through the Chatelperronian and especially the Aurignacian, followed by reduced mobility in the Gravettian and Solutrean, and renewed territorial expansion during the Magdalenian and, likely, the Azilian. In contrast, the Mesolithic is characterised by decreased mobility and thus increased territoriality in both coastal and inland contexts. Faunal isotope values and isoscape predictions reveal that some animals were acquired beyond local foraging ranges during the Palaeolithic, particularly in inland regions with lower {delta}3S values. Isotopic niche analyses indicate partial interspecific overlap consistent with ecological flexibility. Macromammal and micromammal diversity exhibit contrasting patterns, with a significant negative correlation in Simpson and Shannon indices. Macromammal diversity correlates negatively with {delta}3S values, linking increased hunting diversity to expanded catchment areas and longer-distance foraging, whereas micromammal diversity shows positive correlations with {delta}3S, {delta}{superscript 1}3C and {delta}{superscript 1}N reflecting stronger climatic influence. Overall, these results demonstrate that hunter-gatherer behaviour in northern Iberia during the Middle and Late Palaeolithic was highly dynamic, combining logistical and residential strategies that shifted in response to changing environmental conditions, resource distributions and cultural adaptations.

The high metabolic cost of walking in individuals with a transtibial amputation is often attributed to reduced ankle propulsion. However, the cost of stabilizing walking may also increase after amputation, potentially explaining why restoring ankle propulsion does not always normalize metabolic cost. Because the contributions of propulsion and stabilization are difficult to dissociate experimentally, we used simulations to probe the effects of transtibial amputation and different prostheses on walking cost. We simulated gait using a conceptual planar torque-driven model. Leg joint torques were controlled by feedforward and linear, time-varying full state feedback. We computed feedforward torques associated with propulsion and feedback gains for stabilizing walking that minimized expected effort (sum of torques squared) in the presence of sensorimotor noise while imposing stability. We simulated walking for an intact model and three walkers with a prosthesis: a passive, a feedforward-controlled active, and a feedforward and local feedback-controlled active prosthesis. We solved a deterministic approximation of the resultant stochastic optimal control problems for different levels of sensorimotor noise. Feedforward and expected feedback torques were higher for the passive prosthesis walker than for the intact walker. An active prosthesis restored total biological effort (i.e., effort of all but the prosthesis joint) to the level of the intact walker, but this effort was generated by fewer biological joints. Biological feedback effort was higher in prosthesis walkers than in the intact walker. Adding local feedback to an active prosthesis reduced biological feedback effort, but only at low noise levels. Our results suggest that walking with a passive prosthesis increases effort related to both propulsion and stabilization. While active prostheses can support propulsion, local feedback control only marginally reduced stabilization-related effort, suggesting that controllers require sensory information from the rest of the body to fully restore the metabolic cost of walking.

Ecogeographic rules predict that endotherms inhabiting colder environments exhibit larger body sizes and shorter appendages to reduce heat loss. However, these hypotheses have largely been tested using size-based traits, leaving it unclear whether climatic adaptation also alters body proportions that more directly influence surface-area-to-volume ratio. Here, I examined ecogeographic variation in body shape, body size, and relative limb lengths across climatic gradients in three western North American mustelids: American ermine (Mustela richardsonii), American mink (Neogale vison), and Pacific marten (Martes caurina). I then modeled how variation in body shape and size affected surface-area-to-volume ratio. Body size increased in colder climates in all three species, consistently supporting Bergmanns rule. In contrast, only ermines became stouter in colder climates, whereas body shape remained unchanged in minks and martens. Patterns of appendage variation also differed: ermines and martens exhibited relatively longer limbs in colder climates, contrary to Allens rule, whereas only minks exhibited relatively shorter hindlimbs. Modeling showed that increased body size reduced surface-area-to- volume ratio in all species, whereas body shape contributed only in ermines. These findings demonstrate that body shape, body size, and appendage lengths respond independently to climatic gradients, with species-specific ecological and functional constraints shaping thermoregulatory adaptation.

The nautilus (Nautilus sp.) is an early-branching cephalopods. It retains several conchiferan synapomorphies, including an external planispiral biomineralized shell. The shells complex structure allows it to withstand hydrostatic pressure, control buoyancy, and protect against external hazards. In this study, we comprehensively examined shell microstructures across different shell components and regions representing various ontogenetic stages in two adult museum shell specimens. We found that the nautilus shell is composed of five microstructural types (spherulitic, prismatic, nacreous, semi-prismatic, and irregularly oriented prismatic structures) organized into layered architectures within individual shell components and coordinated across the shell as an integrated system. Our observations highlight transitions between distinct microstructures within and across shell components and local variation within individual components such as the dorsal and ventral shell walls, suggesting that these patterns may contribute to shell strength and overall mechanical performance. Variation in caecum morphology suggests that this structure may be developmentally plastic and subject to relatively relaxed structural constraints. These findings show that the Nautilus shell is an integrated biomineral system in which diverse microstructures are organized across shell components to meet functional demands and provide the mechanical strength needed for survival.

Long waiting times for elective surgery remain a persistent challenge in public health systems. Patient prioritisation tools (PPTs) aim to support equitable decision-making by scoring patients based on clinical and non-clinical factors. However, these tools are often developed independently for specific procedures, resulting in non-comparable scores that hinder consistent prioritisation and risk violating the principles of horizontal equity (equal treatment for equal need) and vertical equity (greater need receives higher priority). This study introduces and demonstrates a calibration method to align multiple procedure-specific PPTs onto a unified severity scale. As a proof-of-concept, ten independently developed PPTs from a general surgery unit at a single Australian public hospital were calibrated using an interactive binary search algorithm to identify clinically equivalent patient states across tools, in collaboration with clinicians from the same unit. Each PPT was then aligned to a common reference procedure, and min-max normalisation was applied to standardise scores onto a shared scale. Internal consistency was assessed by comparing calibration outputs against severity rankings from the same clinical team. The calibrated scores demonstrated strong agreement with the team's severity judgements (Kendall's {tau} = -0.734, p < 0.001), indicating that the calibration method preserved the clinicians' intuitive severity rankings. The calibrated scores also preserved the assigned urgency ordering across a cohort of 845 patients. When embedded in an existing dynamic priority formula in simulation, they redistributed waiting time between urgency categories without measurably altering severity concordance. This indicates that the operational effect of the comparable scores depends on the prioritisation formula in which they are embedded, rather than on the calibration itself. These results suggest that the proposed calibration method offers a practical and potentially scalable approach for aligning PPTs across procedures, supporting valid comparisons and enabling more consistent, transparent, and equitable prioritisation. By establishing a common severity scale, this approach addresses a real-world challenge in surgical waiting list management: enabling procedures of inherently different clinical impact to be prioritised fairly and proportionately when competing for shared resources.

Game theory in biology started as an attempt to model animal contests by making assumptions about the fitness costs individuals pay in aggressive interactions. Among the different approaches, a notable one is to construct mechanistic models, using assumptions about behaviours and cognitive processes. Reinforcement learning is an important cognitive process, and we use it here to model pairwise and coalitional contests. We study situations where territorial neighbours become so-called dear enemies. A defending individual can get help from a neighbour through a defender-neighbour coalition against a challenger attempting territory takeover. In our model, coalition members have an advantage in contests in terms of costs of aggression, with the challenger being exposed to aggression from both members and each member only receiving part of the aggression from the challenger. We find that notable costs of border conflicts between neighbours, together with substantial advantages for coalitions, favour intervention. Neighbours intervene when they can help weaker defenders, in this way avoiding costs of border renegotiation with a new and potentially stronger territory owner. We also introduce different forms of perceived costs into the model, which we show correspond to the range from pure mutual assessment to partial self-assessment.

Violent conflicts increasingly involve multiple armed actors competing for influence over shared civilian populations, creating complex dynamics that challenge conventional security analysis and policy design. We present a framework that adapts epidemiological methods informed by the conflict landscape in Nigeria to model multi-actor violent conflict as an epidemic process. We derive a basic insecurity reproduction number ($R_0$), identify violence-free and persistent-violence equilibria, and introduce a novel Civilian Harm Index (CHI) to quantify humanitarian impact. Sensitivity analyses identify recruitment, ideological support from civilian populations, and abduction as the key drivers of conflict persistence and civilian harm. The framework reveals several counterintuitive findings. Interventions that most effectively suppress violence transmission are not necessarily those that minimise civilian harm, demonstrating that epidemic control and humanitarian protection may require distinct optimisation criteria. Likewise, interventions effective against one armed actor may be ineffective, or even counterproductive, when applied uniformly across groups. In addition, prisoner exchange and ransom payments increase violence persistence and civilian harm. Although developed as an illustrative rather than predictive framework, our results show that epidemiological methods provide quantitative metrics for evaluating intervention priorities and trade-offs in complex multi-actor conflicts.

1. Adaptive behavioural strategies require animals to simultaneously navigate social and ecological domains across multiple spatial and temporal scales. Although drones and computer vision have recently transformed the study of wild animal societies, many nocturnal species and those occupying structurally complex habitats remain inaccessible to these approaches, limiting our understanding of behaviour in natural settings. 2. We aimed to determine how behavioural strategies are organised across nested spatial and temporal scales within a wild communication network. 3. We used three-dimensional acoustic localisation and source separation to track individual male Hyperolius sp. A, a nocturnal African reed frog, within a natural rainforest chorus and quantify patterns of site fidelity, movement, spatial organisation, and call-timing interactions. 4. Males exhibited significant site fidelity across nights, while chorus spatial structure varied with local caller density. Within nights, individuals followed a stereotyped behavioural sequence, descending from elevated arboreal refugia before settling into lower calling positions near breeding sites. At finer temporal scales, call-timing interactions varied according to both local competitor density and the proximity of neighbouring rivals. 5. These findings demonstrate that behavioural strategies emerge across nested spatial and temporal scales and that long-term spatial positioning, short-term movement decisions, and moment-to-moment signalling interactions are tightly linked within natural communication networks. More broadly, acoustic localisation provides a powerful framework for studying behaviour in species and habitats that remain difficult to observe using conventional approaches.

Decision-making is key to survival, with choices and behaviour typically shaped by evolutionary pressures to enhance fitness and minimize loss. Inequity aversion, the tendency to respond negatively to unequal reward distributions, is therefore unexpected, as acts of fairness may be costly to the individual in the short term. In social, cooperative species, however, fairness may enhance long-term benefits through stable social interactions. Inequity aversion is believed to promote cooperative social structures and has only been demonstrated in certain social species. Yet, solitary species have not been tested, and whether this behaviour depends on social cooperative structures is unknown. Examining solitary species could clarify whether inequity aversion reflects an adaptation to cooperation or a general cognitive capacity linked to social comparison and reward evaluation. We studied inequity aversion in polar bears (Ursus maritimus), a largely solitary species, using three complementary, non-invasive cognition tests on seven bears from two zoos in the Netherlands. (1) An impunity experiment assessing effort-based inequity, in which bears performed a standardized action to obtain food rewards. (2) A choice-based experiment testing active selection between equal and unequal reward distributions. (3) A no-task control experiment assessing responses to unequal reward distribution without effort. Under effort-based inequity, bears reduced task performance and increased task latency when a partner received a superior reward. Unequal reward distributions did not affect reward acceptance independent of effort. In the choice-based paradigm, bears preferentially selected equal reward distributions with a partner present. Although generalizability to wild populations is limited, these findings demonstrate behavioural aversion of social inequity in a non-cooperative species. Inequality aversion may therefore not be restricted to social, cooperative animals but instead reflect a broadly distributed cognitive mechanism that emerges under relevant social conditions. These findings challenge current theories and advance our understanding of the cognitive foundations of fairness-related behaviour in animals.

Diurnal ectotherms in hot and dry ecosystems face an acquisition trade-off between maximizing collective energy intake and minimizing individual exposure time. We employed optimal foraging and thermoregulation models to examine the surface foraging and thermoregulatory strategies of Pogonomyrmex barbatus foragers in response to habitat warming in a tropical deciduous forest. Foraging activity was evaluated using field-based thermal performance curves (fTPCs) for individual foraging speed and collective foraging success. Thermoregulation was assessed through indices of thermal unsuitability, as well as thermoregulatory effectiveness and exploitation. Our results show that afternoon conditions were significantly hotter and drier than those in the morning. Furthermore, the decoupling of fTPCs was dynamic; while the optimal temperature (Topt) for individual foraging speed remained stable at 44 degrees C, the Topt for collective foraging success shifted from 35 degrees C in the morning to 41 degrees C in the afternoon. This shift in foraging strategy, driven by stressful afternoon conditions, was reflected in a transition of the thermoregulatory strategy. Specifically, the probability of foraging activity decreased as thermal unsuitability increased, with a lower baseline in the afternoon. The thermoregulatory exploitation dropped from 94% in the morning to 63% in the afternoon. Based on thermoregulatory effectiveness, foragers transitioned from an active thermoregulatory strategy in the morning to a thermoconformist strategy in the afternoon while foraging on the surface. So, the observed colonies optimized the balance between individual foraging speed and collective foraging success through a thermoregulatory strategy that was primarily spatial in the morning and strictly temporal in the afternoon. A comparison with historical data from the same site reveals a 40% contraction in the total daily foraging window since 2013.

Gliding enables mammals to forage and escape from predators by moving between discontinuous forests. Its benefits depend not only on glide distance but also on the ability to decelerate and land safely. This study developed a theoretical framework linking glide distance, gliding velocity, aerodynamic braking, body mass, and braking distance. Twenty-two representative distance-velocity observations from eight studies and five species were compiled. Among distance-velocity models, log-distance and saturated with V0 models received nearly equivalent support. Both models predicted increasing velocity with glide distance, with the rate of increase declining at longer distances. For a 1 kg animal undergoing a 60% reduction in velocity, predicted kinetic energy remaining immediately before contact increased from 4.80-5.14J at 20 m to 8.13-8.90 J at 80 m. This velocity reduction corresponded to a dissipation of 84% of approach kinetic energy before contact. Over a braking distance of 1 m, the required mean deceleration increased from 2.57-2.75 g at 20 m to 4.35-4.77 g at 80 m. At 80 m, shortening the braking distance from 4 to 0.5 m increased the required deceleration from 1.09-1.19 to 8.70-9.53 g. These results indicate that the absolute energetic and deceleration requirements of landing increase with glide distance, even when velocity is close to an asymptote. These results provide a quantitative basis for considering aerodynamic braking and landing requirements alongside conventional measures of glide performance. Summary statementModels quantify how glide distance, aerodynamic braking, and braking distance affect pre-contact kinetic energy and deceleration requirements in gliding mammals.

The Triassic was a significant period in the evolution of modern chondrichthyans (sharks, rays and chimaeras), bridging the gap between Paleozoic chondrichthyans and more recognizably modern Mesozoic forms. Although only a handful of Triassic skeletal fossils of chondrichthyans are known worldwide their calcified cartilages provide rare insight into their anatomy, evolution, and lifestyle. Here we use computed tomographic methods to describe six chondrichthyan skeletal fossils from the Carnian (Upper Triassic) Arden Sandstone Formation of Shrewley, Warwickshire, UK, consisting of a partial braincase, jaws, pectoral fin radials, caudal fin hypurals, and dorsal fin basal cartilages, and characterize their paleoenvironment. We assign the braincase and jaws, and tentatively assign the post-cranial remains, to the jalodontid taxon Keuperodus brodiei, previously described on the basis of teeth including those from the same locality. This represents the first known occurrence of articulated chondrichthyan skeletal remains from the Upper Triassic and the first interpretable cranial cartilages of the Order Jalodontiformes. The partial braincase of K. brodiei preserves an unusual basicranial circulation, almost completely embedded in the basicranium, and the jaws have an elongate extended shape; both features are akin to Paleozoic phoebodontid chondrichthyans. Phylogenetic analysis recovers K. brodiei as a stem-group elasmobranch with a close relationship to phoebodonts, one of several Paleozoic shark lineages to have independently survived the end-Permian mass extinction. However, unlike Phoebodontiformes and all other Jalodontiformes, K. brodiei occupied freshwater lake shorelines and associated fluvial feeder channels, revealing a possible freshwater refugium for Jalodontiformes towards at the end of their stratigraphic range.

The mechanisms by which organisms extract relevant information from complex sensory signals and use it for decision-making constitute a fundamental issue in biological and cognitive sciences. In social animal societies, individual decision-making is profoundly shaped by information provided by conspecifics. Collective patch-foraging experiments in the laboratory provide a controlled setting in which social information use can be quantified. Here, we consider a go/no-go task in which groups choose between two patches differing in food reward probability. We use agent-based simulations, underpinned by an augmented collective drift-diffusion model, to investigate alternative mechanisms for representing and integrating social information. We consider two representations, continuous (counting representation) and discrete (pulsatile representation), and two integration mechanisms, biasing the decision threshold (threshold modulation) and modifying the accumulated belief (belief modulation), yielding four distinct social models, in addition to a non-interacting model. We first characterize the collective dynamics generated by these models across cognitive parameters and experimental conditions. The temporal dynamics of group accuracy provide informative signatures of the underlying mechanisms. We then assess model selection and parameter identifiability using Bayesian inference and Wasserstein distance minimization, applied to group-accuracy and departure-time distributions. Bayesian inference using distributions of group accuracy provides the most reliable identification across the conditions considered. Importantly, model selection and parameter identifiability are associated with different aspects of collective behavior: model selection is closely linked to the presence of oscillations in the temporal dynamics, whereas parameter identifiability is more closely related to the global accuracy value. Thus, the information available for distinguishing the underlying cognitive mechanisms is not necessarily the same as that required to recover their parameters. Our results further show that identification depends not only on model structure but also on the experimental conditions. Overall, this study provides practical guidelines for identifying socio-cognitive mechanisms in collective foraging experiments.