Soft-tissue fossilization illuminates the stepwise evolution of the ray-finned fish brain.

A complex brain is central to the success of backboned animals. However, direct evidence bearing on vertebrate brain evolution comes almost exclusively from extant species, leaving substantial knowledge gaps. Although rare, soft-tissue preservation in fossils can yield unique insights on patterns of neuroanatomical evolution. Paleontological evidence from an exceptionally preserved Pennsylvanian (∼318 Ma) actinopterygian, Coccocephalus, calls into question prior interpretations of ancestral actinopterygian brain conditions. However, the ordering and timing of major evolutionary innovations, such as an everted telencephalon, modified meningeal tissues, and hypothalamic inferior lobes, remain unclear. Here, we report two distinct actinopterygian morphotypes from the latest Carboniferous-earliest Permian (∼299 Ma) of Brazil that show extensive soft-tissue preservation of brains, cranial nerves, eyes, and potential cardiovascular tissues. These fossils corroborate inferences drawn from ✝Coccocephalus, while adding new information about neuroanatomical evolution. Skeletal features indicate that one of these Brazilian morphotypes is more closely related to living actinopterygians than the other, which is also reflected in soft-tissue features. Significantly, the more crownward morphotype shows a key neuroanatomical feature of extant actinopterygians-an everted telencephalon-that is absent in the other morphotype and ✝Coccocephalus. All preserved Paleozoic actinopterygian brains show broad similarities, including an invaginated cerebellum, hypothalamus inferior lobes, and a small forebrain. In each case, preserved brains are substantially smaller than the enclosing cranial chamber. The neuroanatomical similarities shared by this grade of Permo-Carboniferous actinopterygians reflect probable primitive conditions for actinopterygians, providing a revised model for interpreting brain evolution in a major branch of the vertebrate tree of life.

The first articulated skeletons of enigmatic Late Cretaceous billfish-like actinopterygians.

Only few candidates of Mesozoic fishes with a similar body plan and ecological niche to the modern billfishes are suggested as their analogues. Several specimens were recovered from Cenomanian deposits in Germany and Lebanon and display a billfish-like fusiform body with elongated premaxillae. They are found close to the plethodids and show a unique combination of characters (rostrum pointed and extremely elongated, double articular head of the quadrate, anteroposteriorly elongated abdominal centra indicating a slender body and different types of scales on the body) allowing their inclusion in a new genus. Two 'Protosphyraena' species are also assigned to this new genus. This fish can be considered as an ecological analogue to the extant xiphioids sharing their feeding habits. This fish was abundant and roamed, as an apex predator, the Central Tethys and the Boreal realms during the Cenomanian.

Bony-fish-like scales in a Silurian maxillate placoderm.

Major groups of jawed vertebrates exhibit contrasting conditions of dermal plates and scales. But the transition between these conditions remains unclear due to rare information on taxa occupying key phylogenetic positions. The 425-million-year-old fish Entelognathus combines an unusual mosaic of characters typically associated with jawed stem gnathostomes or crown gnathostomes. However, only the anterior part of the exoskeleton was previously known for this very crownward member of the gnathostome stem. Here, we report a near-complete post-thoracic exoskeleton of Entelognathus. Strikingly, its scales are large and some are rhomboid, bearing distinctive peg-and-socket articulations; this combination was previously only known in osteichthyans and considered a synapomorphy of that group. The presence in Entelognathus of an anal fin spine, previously only found in some stem chondrichthyans, further illustrates that many characters previously thought to be restricted to specific lineages within the gnathostome crown likely arose before the common ancestor of living jawed vertebrates.

Fossil evidence for a pharyngeal origin of the vertebrate pectoral girdle.

The origin of vertebrate paired appendages is one of the most investigated and debated examples of evolutionary novelty1-7. Paired appendages are widely considered as key innovations that enabled new opportunities for controlled swimming and gill ventilation and were prerequisites for the eventual transition from water to land. The past 150 years of debate8-10 has been shaped by two contentious theories4,5: the ventrolateral fin-fold hypothesis9,10 and the archipterygium hypothesis8. The latter proposes that fins and girdles evolved from an ancestral gill arch. Although studies in animal development have revived interest in this idea11-13, it is apparently unsupported by fossil evidence. Here we present palaeontological support for a pharyngeal basis for the vertebrate shoulder girdle. We use computed tomography scanning to reveal details of the braincase of Kolymaspis sibirica14, an Early Devonian placoderm fish from Siberia, that suggests a pharyngeal component of the shoulder. We combine these findings with refreshed comparative anatomy of placoderms and jawless outgroups to place the origin of the shoulder girdle on the sixth branchial arch. These findings provide a novel framework for understanding the origin of the pectoral girdle. Our evidence clarifies the location of the presumptive head-trunk interface in jawless fishes and explains the constraint on branchial arch number in gnathostomes15. The results revive a key aspect of the archipterygium hypothesis and help reconcile it with the ventrolateral fin-fold model.

Nebulized Ketamine Used for Managing Ankle Fracture in the Prehospital Emergency Setting: A Case Report.

INTRODUCTION: Acute traumatic limb injury is a common complaint of patients presenting to the emergency department (ED). Ketamine is an effective analgesic administered via intravenous (IV), intranasal (IN), intramuscular (IM), and nebulized routes in the ED. It has also been used in the prehospital setting via IV, IM, and IN routes. Recent studies have proposed the prehospital use of nebulized ketamine via breath-actuated nebulizer (BAN) as a noninvasive and effective method of analgesic delivery, as well as an alternative to opioid analgesia. CASE REPORT: We present a case of a patient with right ankle fracture after a 12-foot fall who subsequently received 0.75 milligrams per kilogram of nebulized ketamine via BAN in the prehospital setting. The patient reported improvement of pain from 8/10 to 3/10 on the pain scale without need for additional pain medication during prehospital transport. This report supports the use of nebulized ketamine via BAN in the prehospital setting for acute traumatic limb injuries. CONCLUSION: The use of nebulized ketamine via BAN in the prehospital setting may be an effective analgesic option for the management of patients with acute traumatic limb injuries, particularly in those with difficult IV access, where mucosal atomization devices are not accessible, or where opioid-sparing treatments are preferable.

How to tuna fish: constraint, convergence, and integration in the neurocranium of pelagiarian fishes.

Morphological evolution of the vertebrate skull has been explored across a wide range of tetrapod clades using geometric morphometrics, but the application of these methods to teleost fishes, accounting for roughly half of all vertebrate species, has been limited. Here we present the results of a study investigating 3D morphological evolution of the neurocranium across 114 species of Pelagiaria, a diverse clade of open-ocean teleost fishes that includes tuna and mackerel. Despite showing high shape disparity overall, taxa from all families fall into three distinct morphological clusters. Convergence in shape within clusters is high, and phylogenetic signal in shape data is significant but low. Neurocranium shape is significantly correlated with body elongation and significantly but weakly correlated with size. Diet and habitat depth are weakly correlated with shape, and nonsignificant after accounting for phylogeny. Evolutionary integration in the neurocranium is high, suggesting that convergence in skull shape and the evolution of extreme morphologies are associated with the correlated evolution of neurocranial elements. These results suggest that shape evolution in the pelagiarian neurocranium reflects the extremes in elongation found in body shape but is constrained along relatively few axes of variation, resulting in repeated evolution toward a restricted range of morphologies.

Exceptional fossil preservation and evolution of the ray-finned fish brain.

Brain anatomy provides key evidence for the relationships between ray-finned fishes1, but two major limitations obscure our understanding of neuroanatomical evolution in this major vertebrate group. First, the deepest branching living lineages are separated from the group's common ancestor by hundreds of millions of years, with indications that aspects of their brain morphology-like other aspects of their anatomy2,3-are specialized relative to primitive conditions. Second, there are no direct constraints on brain morphology in the earliest ray-finned fishes beyond the coarse picture provided by cranial endocasts: natural or virtual infillings of void spaces within the skull4-8. Here we report brain and cranial nerve soft-tissue preservation in Coccocephalus wildi, an approximately 319-million-year-old ray-finned fish. This example of a well-preserved vertebrate brain provides a window into neural anatomy deep within ray-finned fish phylogeny. Coccocephalus indicates a more complicated pattern of brain evolution than suggested by living species alone, highlighting cladistian apomorphies1 and providing temporal constraints on the origin of traits uniting all extant ray-finned fishes1,9. Our findings, along with a growing set of studies in other animal groups10-12, point to the importance of ancient soft tissue preservation in understanding the deep evolutionary assembly of major anatomical systems outside of the narrow subset of skeletal tissues13-15.

DiceCT for fishes: recommendations for pairing iodine contrast agents with µCT to visualize soft tissues in fishes.

Computed tomography (CT) scanning and other high-throughput three-dimensional (3D) visualization tools are transforming the ways we study morphology, ecology and evolutionary biology research beyond generating vast digital repositories of anatomical data. Contrast-enhanced chemical staining methods, which render soft tissues radio-opaque when coupled with CT scanning, encompass several approaches that are growing in popularity and versatility. Of these, the various diceCT techniques that use an iodine-based solution like Lugol's have provided access to an array of morphological data sets spanning extant vertebrate lineages. This contribution outlines straightforward means for applying diceCT techniques to preserved museum specimens of cartilaginous and bony fishes, collectively representing half of vertebrate species diversity. This study contrasts the benefits of using either aqueous or ethylic Lugol's solutions and reports few differences between these methods with respect to the time required to achieve optimal tissue contrast. It also explores differences in minimum stain duration required for different body sizes and shapes and provides recommendations for staining specimens individually or in small batches. As reported by earlier studies, the authors note a decrease in pH during staining with either aqueous or ethylic Lugol's. Nonetheless, they could not replicate the drastic declines in pH reported elsewhere. They provide recommendations for researchers and collections staff on how to incorporate diceCT into existing curatorial practices, while offsetting risk to specimens. Finally, they outline how diceCT with Lugol's can aid ichthyologists of all kinds in visualizing anatomical structures of interest: from brains and gizzards to gas bladders and pharyngeal jaw muscles.

Phylogenomics of the Ancient and Species-Depauperate Gars Tracks 150 Million Years of Continental Fragmentation in the Northern Hemisphere.

Reconstructing deep-time biogeographic histories is limited by the comparatively recent diversification of most extant lineages. Ray-finned fishes, which include nearly half of all living vertebrates, are no exception. Although most lineages of ray-finned fishes radiated around the Cretaceous-Paleogene boundary, a handful of ancient, species-poor clades still persist. These lineages can illuminate very old biogeographic trends, but their low species richness can also limit the reconstruction of these patterns. The seven extant species of gars distributed in freshwater habitats in North America and Cuba are an old clade with a fossil record spanning over 150 million years of Earth history. Using a genomic data set of DNA sequences of 1105 exons for the seven living species and an updated morphological matrix of all extant and extinct taxa, we infer the phylogenetic relationships of gars and test how divergence times and biogeographic reconstructions are influenced by sequential and joint estimation and the effect on these inferences when using different taxon sets based on fossil completeness. Our analyses consistently show that the two extant gar genera Atractosteus and Lepisosteus diverged approximately 105 million years ago and many of the inferred divergences in the gar time-calibrated phylogeny closely track major Mesozoic tectonic events, including the separation of the Americas, the expansion of the early Atlantic, and the Cretaceous reorganization of North American river systems. The crown clades Atractosteus and Lepisosteus originated in the Cenozoic of eastern North America, implying that this region has served as both the origin of extant gar diversity and the refugium of this iconic ancient lineage. These results exemplify how combining phylogenomics with the fossil record provides congruence around the evolutionary history of ancient clades like gars and can reveal long-lost biogeographic patterns. [Lepisosteidae; fossilized birth death; biogeography; phylogenomics; paleontology.].

A Late Devonian actinopterygian suggests high lineage survivorship across the end-Devonian mass extinction.

Many accounts of the early history of actinopterygians (ray-finned fishes) posit that the end-Devonian mass extinction had a major influence on their evolution. Existing phylogenies suggest this episode could have acted as a bottleneck, paring the early diversity of the group to a handful of survivors. This picture, coupled with increases in taxonomic and morphological diversity in the Carboniferous, contributes to a model of explosive post-extinction radiation. However, most actinopterygians from within a roughly 20-million year (Myr) window surrounding the extinction are poorly known, contributing to uncertainty about the meaning of these patterns. Here, we report an exceptionally preserved fossil from 7 Myr before the extinction that reveals unexpected anatomical features. Palaeoneiros clackorum gen. et sp. nov. nests within a clade of post-Devonian species and, in an expanded phylogenetic analysis, draws multiple lineages of Carboniferous actinopterygians into the Devonian. This suggests cryptic but extensive lineage diversification in the latest Devonian, followed by more conspicuous feeding and locomotor structure diversification in the Carboniferous. Our revised model matches more complex patterns of divergence, survival and diversification around the Devonian/Carboniferous boundary in other vertebrate clades. It also fundamentally recalibrates the onset of diversification early in the history of this major radiation.

Perceptions and Barriers to Administering Vasopressors in the Prehospital Setting.

Introduction Vasopressor administration is a critical medical intervention for patients with hypotension in undifferentiated shock states. Over the years, prehospital care has advanced with protocols and training that allow paramedics in the field to administer a variety of vasopressors. The primary objective of this investigation was to evaluate vasopressor experience among paramedics with regard to preference as well as the barriers to its preparation and administration. Methods A cross-sectional survey of vasopressor use by nationally certified paramedics (NRPs) was performed. A 20-item questionnaire was constructed to capture the prehospital perceptions and barriers of dopamine infusion, norepinephrine infusion, and IV bolus "push-dose" epinephrine (PD-E). Data collection was carried out from June to September 2021. Results A total of 44 responses were obtained (response rate = 44%). All participants had experience using vasopressors and understood their medical indications. Overall, PD-E was the most common vasopressor used in the prehospital setting, and participants felt equally confident in "using" and "preparing" it. Participants felt less confident with "using" and "preparing" vasopressors that required channel setup and maintaining a flow rate. Younger paramedics with less than five years of experience were more eager to use norepinephrine if trucks were stocked with pre-mixed norepinephrine rather than the current formulation that required compounding.  Conclusion This study provided preliminary data that evaluated perceptions of vasopressor use in the prehospital setting among paramedics in a large urban environment. Preference and barriers to its preparation and administration were surveyed. Further research is needed to identify the interventions to reduce barriers and allow paramedics to be less limited by logistical considerations when choosing vasopressors in the prehospital setting.

Recreational drug toxicity with severe hyperthermia: Rapid onsite treatment and clinical course.

Electronic dance music festivals have gained notoriety in the critical care and emergency medicine fields due to an alarming incidence of hospitalizations and deaths related to the high prevalence of recreational drug use. Recreational drug use toxicity, in part related to sympathomimetic toxidromes, may cause hyponatremia, seizures, rhabdomyolysis, hyperkalemia, acidosis, coagulopathy, circulatory shock, multi-organ failure, and even death. This wide-ranging syndrome has been referred to as psychostimulant drug-induced toxicity. Rapid onsite diagnosis and treatment, with attention to the A-B-C's of clinical emergencies, is essential to preserve life. We describe a patient presenting with the highest recorded core temperature in a survivor of psychostimulant drug-induced toxicity, and emphasize management principles of this life-threatening and increasingly prevalent condition.

Prolonged morphological expansion of spiny-rayed fishes following the end-Cretaceous.

Spiny-rayed fishes (Acanthomorpha) dominate modern marine habitats and account for more than a quarter of all living vertebrate species. Previous time-calibrated phylogenies and patterns from the fossil record explain this dominance by correlating the origin of major acanthomorph lineages with the Cretaceous-Palaeogene mass extinction. Here we infer a time-calibrated phylogeny using ultraconserved elements that samples 91.4% of all acanthomorph families and investigate patterns of body shape disparity. Our results show that acanthomorph lineages steadily accumulated throughout the Cenozoic and underwent a significant expansion of among-clade morphological disparity several million years after the end-Cretaceous. These acanthomorph lineages radiated into and diversified within distinct regions of morphospace that characterize iconic lineages, including fast-swimming open-ocean predators, laterally compressed reef fishes, bottom-dwelling flatfishes, seahorses and pufferfishes. The evolutionary success of spiny-rayed fishes is the culmination of multiple species-rich and phenotypically disparate lineages independently diversifying across the globe under a wide range of ecological conditions.

A Permian fish reveals widespread distribution of neopterygian-like jaw suspension.

The actinopterygian crown group (comprising all living ray-finned fishes) originated by the end of the Carboniferous. However, most late Paleozoic taxa are stem actinopterygians, and broadly resemble stratigraphically older taxa. The early Permian †Brachydegma caelatum is notable for its three-dimensional preservation and past phylogenetic interpretations as a nested member of the neopterygian crown. Here, we use computed microtomography to redescribe †Brachydegma, uncovering an unanticipated combination of primitive (e.g., aortic canal; immobile maxilla) and derived (e.g., differentiated occipital ossifications; posterior stem of parasphenoid; two accessory hyoidean ossifications; double jaw joint) dermal and endoskeletal traits relative to most other Paleozoic actinopterygians. Some of these features were previously thought to be restricted to the neopterygian crown. The precise phylogenetic position of †Brachydegma is unclear, with placements either on the polypterid stem or as an early-diverging stem neopterygian. However, our analyses decisively reject previous placements of †Brachydegma in the neopterygian crown. Critically, we demonstrate that key endoskeletal components of the hyoid portion of the suspensorium of crown neopterygians appeared deeper in the tree than previously thought.

The rapid evolution of lungfish durophagy.

Innovations relating to the consumption of hard prey are implicated in ecological shifts in marine ecosystems as early as the mid-Paleozoic. Lungfishes represent the first and longest-ranging lineage of durophagous vertebrates, but how and when the various feeding specializations of this group arose remain unclear. Two exceptionally preserved fossils of the Early Devonian lobe-finned fish Youngolepis reveal the origin of the specialized lungfish feeding mechanism. Youngolepis has a radically restructured palate, reorienting jaw muscles for optimal force transition, coupled with radiating entopterygoid tooth rows like those of lungfish toothplates. This triturating surface occurs in conjunction with marginal dentition and blunt coronoid fangs, suggesting a role in crushing rather than piercing prey. Bayesian tip-dating analyses incorporating these morphological data indicate that the complete suite of lungfish feeding specializations may have arisen in as little as 7 million years, representing one of the most striking episodes of innovation during the initial evolutionary radiations of bony fishes.

When race trumps political ideology: Black teachers who advocate for social responsibility are penalized by both liberals and conservatives.

Meritocracy is a prominent narrative embedded in America's educational system: work hard and anyone can achieve success. Yet, racial disparities in education suggest this narrative does not tell the full story. Four studies (N = 1,439) examined how applicants for a teaching position are evaluated when they invoke different narratives regarding who or what is to blame for racial disparities (i.e., individuals vs. systems). We hypothesized these evaluations would differ depending on teacher race (Black/White) and evaluator political orientation. Results revealed conservatives evaluated Black and White applicants advocating for personal responsibility more favorably than applicants advocating for social responsibility. Liberals preferred social responsibility applicants, but only when they were White. They were more ambivalent in their evaluations and hiring decisions if the applicants were Black. Our findings suggest that Black applicants advocating for social change are penalized by both liberal and conservative evaluators.

Fossilized cell structures identify an ancient origin for the teleost whole-genome duplication.

Teleost fishes comprise one-half of all vertebrate species and possess a duplicated genome. This whole-genome duplication (WGD) occurred on the teleost stem lineage in an ancient common ancestor of all living teleosts and is hypothesized as a trigger of their exceptional evolutionary radiation. Genomic and phylogenetic data indicate that WGD occurred in the Mesozoic after the divergence of teleosts from their closest living relatives but before the origin of the extant teleost groups. However, these approaches cannot pinpoint WGD among the many extinct groups that populate this 50- to 100-million-y lineage, preventing tests of the evolutionary effects of WGD. We infer patterns of genome size evolution in fossil stem-group teleosts using high-resolution synchrotron X-ray tomography to measure the bone cell volumes, which correlate with genome size in living species. Our findings indicate that WGD occurred very early on the teleost stem lineage and that all extinct stem-group teleosts known so far possessed duplicated genomes. WGD therefore predates both the origin of proposed key innovations of the teleost skeleton and the onset of substantial morphological diversification in the clade. Moreover, the early occurrence of WGD allowed considerable time for postduplication reorganization prior to the origin of the teleost crown group. This suggests at most an indirect link between WGD and evolutionary success, with broad implications for the relationship between genomic architecture and large-scale evolutionary patterns in the vertebrate Tree of Life.