Increasing the impact of vertebrate scientific collections through 3D imaging: The openVertebrate (oVert) Thematic Collections Network.

The impact of preserved museum specimens is transforming and increasing by three-dimensional (3D) imaging that creates high-fidelity online digital specimens. Through examples from the openVertebrate (oVert) Thematic Collections Network, we describe how we created a digitization community dedicated to the shared vision of making 3D data of specimens available and the impact of these data on a broad audience of scientists, students, teachers, artists, and more. High-fidelity digital 3D models allow people from multiple communities to simultaneously access and use scientific specimens. Based on our multiyear, multi-institution project, we identify significant technological and social hurdles that remain for fully realizing the potential impact of digital 3D specimens.

Diving dinosaurs? Caveats on the use of bone compactness and pFDA for inferring lifestyle.

The lifestyle of spinosaurid dinosaurs has been a topic of lively debate ever since the unveiling of important new skeletal parts for Spinosaurus aegyptiacus in 2014 and 2020. Disparate lifestyles for this taxon have been proposed in the literature; some have argued that it was semiaquatic to varying degrees, hunting fish from the margins of water bodies, or perhaps while wading or swimming on the surface; others suggest that it was a fully aquatic underwater pursuit predator. The various proposals are based on equally disparate lines of evidence. A recent study by Fabbri and coworkers sought to resolve this matter by applying the statistical method of phylogenetic flexible discriminant analysis to femur and rib bone diameters and a bone microanatomy metric called global bone compactness. From their statistical analyses of datasets based on a wide range of extant and extinct taxa, they concluded that two spinosaurid dinosaurs (S. aegyptiacus, Baryonyx walkeri) were fully submerged "subaqueous foragers," whereas a third spinosaurid (Suchomimus tenerensis) remained a terrestrial predator. We performed a thorough reexamination of the datasets, analyses, and methodological assumptions on which those conclusions were based, which reveals substantial problems in each of these areas. In the datasets of exemplar taxa, we found unsupported categorization of taxon lifestyle, inconsistent inclusion and exclusion of taxa, and inappropriate choice of taxa and independent variables. We also explored the effects of uncontrolled sources of variation in estimates of bone compactness that arise from biological factors and measurement error. We found that the ability to draw quantitative conclusions is limited when taxa are represented by single data points with potentially large intrinsic variability. The results of our analysis of the statistical method show that it has low accuracy when applied to these datasets and that the data distributions do not meet fundamental assumptions of the method. These findings not only invalidate the conclusions of the particular analysis of Fabbri et al. but also have important implications for future quantitative uses of bone compactness and discriminant analysis in paleontology.

Spinosaurus is not an aquatic dinosaur.

A predominantly fish-eating diet was envisioned for the sail-backed theropod dinosaur Spinosaurus aegyptiacus when its elongate jaws with subconical teeth were unearthed a century ago in Egypt. Recent discovery of the high-spined tail of that skeleton, however, led to a bolder conjecture that S. aegyptiacus was the first fully aquatic dinosaur. The 'aquatic hypothesis' posits that S. aegyptiacus was a slow quadruped on land but a capable pursuit predator in coastal waters, powered by an expanded tail. We test these functional claims with skeletal and flesh models of S. aegyptiacus. We assembled a CT-based skeletal reconstruction based on the fossils, to which we added internal air and muscle to create a posable flesh model. That model shows that on land S. aegyptiacus was bipedal and in deep water was an unstable, slow-surface swimmer (<1 m/s) too buoyant to dive. Living reptiles with similar spine-supported sails over trunk and tail are used for display rather than aquatic propulsion, and nearly all extant secondary swimmers have reduced limbs and fleshy tail flukes. New fossils also show that Spinosaurus ranged far inland. Two stages are clarified in the evolution of Spinosaurus, which is best understood as a semiaquatic bipedal ambush piscivore that frequented the margins of coastal and inland waterways.

Wing Shape in Waterbirds: Morphometric Patterns Associated with Behavior, Habitat, Migration, and Phylogenetic Convergence.

Wing shape plays a critical role in flight function in birds and other powered fliers and has been shown to be correlated with flight performance, migratory distance, and the biomechanics of generating lift during flight. Avian wing shape and flight mechanics have also been shown to be associated with general foraging behavior and habitat choice. We aim to determine if wing shape in waterbirds, a functionally and ecologically diverse assemblage united by their coastal and aquatic habitats, is correlated with various functional and ecological traits. We applied geometric morphometric approaches to the spread wings of a selection of waterbirds to search for evolutionary patterns between wing shape and foraging behavior, habitat, and migratory patterns. We found strong evidence of convergent evolution of high and low aspect ratio wing shapes in multiple clades. Foraging behavior also consistently exhibits strong evolutionary correlations with wing shape. Habitat, migration, and flight style, in contrast, do not exhibit significant correlation with wing shape in waterbirds. Although wing shape is critical to aerial flight function, its relationship to habitat and periodic locomotor demands such as migration is complex.

La forme de l'aile joue un rôle essentiel dans le vol chez les oiseaux et les autres animaux présentant un vol actif. Il a été démontré que cette dernière est corrélée aux performances de vol, à la distance de migration et à la biomécanique générant de la portance pendant le vol. La forme de l'aile et la mécanique du vol chez les oiseaux sont également associées au comportement alimentaire et au choix de l'habitat. Notre objectif est de déterminer si la forme de l'aile chez les oiseaux aquatiques, un assemblage fonctionnellement et écologiquement diversifié uni par leurs habitats côtiers, est corrélée à divers traits fonctionnels et écologiques. Nous nous sommes appuyés sur des techniques de morphométrie géométrique appliquées aux ailes déployées d'une sélection d'oiseaux aquatiques afin de mettre en évidence un lien évolutif entre la forme des ailes, le comportement alimentaire, l'habitat et les mouvements migratoires. Nous avons trouvé des preuves concrètes de l'évolution convergente des formes d'ailes à fort et faible allongements dans plusieurs clades. Le comportement alimentaire présente également de fortes corrélations évolutives avec la forme des ailes. L'habitat, la migration et le style de vol, en revanche, ne présentent pas de corrélation significative avec la forme de l'aile chez les oiseaux aquatiques. Bien que la forme de l'aile soit essentielle au vol, sa relation avec l'habitat et les exigences locomotrices périodiques telles que la migration reste complexe.La forma del ala tiene un papel crítico en el vuelo de las aves y otros voladores activos, y se ha comprobado que se correlaciona con la eficiencia del vuelo, la distancia migratoria y la biomecánica en la generación de sustentación durante el vuelo. La forma de las alas de las aves y la mecánica del vuelo también están relacionadas con las estrategias de búsqueda de alimento y elección de hábitat. Nuestro propósito es determinar si la forma del ala se correlaciona con varias características funcionales y ecológicas en aves acuáticas, un grupo funcional y ecológicamente diverso que comparten un hábito costero y acuático. Se utilizó morfometría geométrica en alas extendidas de una selección de aves acuáticas para buscar patrones evolutivos entre la morfología del ala y estrategia de alimentación, hábitat y patrones migratorios. Se ha encontrado evidencia robusta de evolución convergente de morfologías de ala con mayor o menor alargamiento en varios clados. El comportamiento de búsqueda de alimento también tiene correlaciones evolutivas consistentes con la morfología del ala. Sin embargo, el hábitat, tipo de migración y tipo de vuelo no muestran una correlación significativa con la morfología del ala en aves acuáticas. Aunque la forma del ala es crítica para la función del vuelo aéreo, su relación con el hábitat o demandas locomotoras periódicas como la migración son complejas.