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opencc-zeroJan 2024View details →

Rapid divergent evolution of internal female genitalia and the coevolution of male genital morphology revealed by micro-computed tomography

Animal genitalia are thought to evolve rapidly and divergently in response to sexual selection. Studies of genital evolution have focused largely on male genitalia, with our understanding of female genital evolution relatively limited. The paucity of work on female genital morphology is likely due to problems faced in quantifying shape variation, due to their composition and accessibility. Here we use a combination of micro-computed tomography, landmark-free shape quantification, and phylogenetic analysis to quantify the rate of female genital shape evolution among 29 species of Antichiropus millipedes, and the coevolution of male genitalia. We found significant variation in female and male genital shape among species. While male genital shape showed significant phylogenetic signal, female genital shape did not. Male genital shape was found to be evolving 1.2 times faster than female genital shape. Female and male genital shapes exhibited strongly correlated evolution, indicating that genital shape changes in one sex are associated with corresponding changes in the genital shape of the other sex. This study adds novel insight into our growing understanding of how female genitalia can evolve rapidly and divergently and highlights the advantages of three-dimensional techniques and multivariate analyses in studies of female genital evolution.

opencc-zeroFeb 2024View details →

Early origins of divergent patterns of morphological evolution on the mammal and reptile stem-lineages

The origin of amniotes 320 million years ago signalled independence from water in vertebrates and was closely followed by divergences within the mammal and reptile stem lineages (Synapsida and Reptilia). Early members of both groups had highly similar morphologies, being superficially 'lizard-like' forms with many plesiomorphies. However, the extent to which they might have exhibited divergent patterns of evolutionary change, with potential to explain the large biological differences between their living members, is unresolved. We use a new, comprehensive phylogenetic dataset to quantify variation in rates and constraints of morphological evolution among Carboniferous–early Permian amniotes. We find evidence for an early burst of evolutionary rates, resulting in the early origins of morphologically distinctive subgroups that mostly persisted through the Cisuralian. Rates declined substantially through time, especially in reptiles. Early reptile evolution was also more constrained compared to early synapsids, exploring a more limited character state space. Postcranial innovation in particular was important in early synapsids, potentially related to their early origins of large body size. In contrast, early reptiles predominantly varied the temporal region, suggesting disparity in skull and jaw kinematics, and foreshadowing the variability of cranial biomechanics seen in reptiles today. Our results demonstrate that synapsids and reptiles underwent an early divergence of macroevolutionary patterns. This laid the foundation for subsequent evolutionary events and may be critical in understanding the substantial differences between mammals and reptiles today. Potential explanations include an early divergence of developmental processes or of ecological factors, warranting cross-disciplinary investigation.

opencc-zeroFeb 2024View details →

The evolution of femoral morphology in giant non-avian theropod dinosaurs

Theropods are obligate bipedal dinosaurs that appeared 230 million years ago and are still extant as birds. Their history is characterized by extreme variations in body mass, with gigantism evolving convergently between many lineages. However, no quantification of hindlimb functional morphology has shown if these body mass increases led to similar specializations between distinct lineages. Here we studied femoral shape variation across 41 species of theropods (n= 68 specimens) using a high-density 3D geometric morphometric approach. We demonstrated that the heaviest theropods evolved wider epiphyses and a more distally located fourth trochanter, as previously demonstrated in early archosaurs, along with an upturned femoral head and a mediodistal crest that extended proximally along the shaft. Phylogenetically informed analyses highlighted that these traits evolved convergently within six major theropod lineages, regardless of their maximum body mass. Conversely, the most gracile femora were distinct from the rest of the dataset, which we interpret as a femoral specialization to "miniaturization" evolving close to the bird lineage (Avialae). Our results support a gradual evolution of known "avian" features, such as the fusion between lesser and greater trochanters and a reduction of the epiphyses' offset, independently from body mass variations, which may relate to a more "avian" type of locomotion (more knee- than hip-driven). The distinction between body mass variations and a more "avian" locomotion is represented by a decoupling in the mediodistal crest morphology, whose biomechanical nature should be studied to better understand the importance of its functional role in gigantism, miniaturization and higher parasagittal abilities.

opencc-zeroMar 2024View details →

Different selection regimes explain morphological evolution in fossorial lizards

Independent origins of similar phenotypes are ubiquitous to the evolutionary process and evoke strong and recurrent environmental associations. Snakelike lizards evolved multiple times and are often portrayed as limb-reduced and body-elongated outcomes from shared selection associated with fossoriality. However, a refined evaluation including specific head traits and subtle differences in subterranean microhabitats unveils some degree of uniqueness even among lineages traditionally interpreted as phenotypically similar. Here we address regimes of selection in fossorial lizards accounting for differences in the burrowing substrate and emphasizing head shape in addition to body and limbs. We assembled an ecomorphological database comprising 213 species from all major lizard clades, and then characterized contemporary morphological diversity and modeled phenotypic evolution to test the hypothesis that fossoriality encompasses at least two distinct selection regimes. We identified two ecomorphological groups within the fossorial lizards: moist-soil fossorial and dry-soil fossorial. Both groups evolved towards distinct adaptive optima concerning head shape and limb size. Despite some degree of uniqueness, these groups also share similar patterns in specific traits. Dry-soil fossorial lizards present less morphological variation than moist-soil fossorial, possibly due to the combination of distinct sets of selective pressures with shared ancestry. Our study provides evidence that an often-interpreted general adaptive regime (e.g., fossoriality) may in fact comprise enough ecological and functional diversity to elicit several distinct ecomorphological associations despite overall convergence among phenotypic traits.

opencc-zeroApr 2024View details →

The evolution of plasticity in brain morphology following colonization of an ecologically divergent habitat in Trinidadian guppies

Natural environments are constantly changing. To survive, organisms will either need to rapidly adapt to new conditions or colonize new habitats. Colonization has been hypothesized to select for increased plasticity as well as increased brain size, though empirical tests of these effects have proven difficult to evaluate. In particular, the degree to which plasticity of brain morphology can evolve, and its subsequent ecological consequences have rarely been explored. Trinidadian guppies (Poecilia reticulata) are known for their repeated adaptation to ancestral high-predation (HP) and derived low-predation (LP) environments. We used this system to examine the evolution and plasticity of brain morphology. We exposed second-generation offspring of individuals collected from HP and LP sites to two different kinds of environmental treatments: predation cues and conspecific social environment. We found that guppies descended from a colonized LP habitat showed greater plasticity in brain morphology than descendants of their ancestral HP population, supporting the hypothesis that plasticity of brain morphology may increase fitness after colonization of a novel habitat. Additionally, we show sexual dimorphism in brain morphology plasticity. Overall, these results suggest the evolution of brain morphology plasticity as an important mechanism that allows for ecological diversification and colonization of novel habitats.

opencc-by-4.0Mar 2024View details →

Data from: Diversity and molecular evolution of non-visual opsin genes across environmental, developmental, and morphological adaptations in frogs

Dataset for the article Diversity and molecular evolution of non-visual opsin genes across environmental, developmental, and morphological adaptations in frogs. Includes non-visual opsin coding sequences from frogs, sequence alingments, phylogenetics trees, and raw PAML results files.

opencc-zeroMar 2022View details →

Stabilized morphological evolution of spiders despite mosaic changes in foraging ecology

A prominent question in animal research is how the evolution of morphology and ecology interact in the generation of phenotypic diversity. Spiders are some of the most abundant arthropod predators in terrestrial ecosystems and exhibit a diversity of foraging styles. It remains unclear how spider body size and proportions relate to foraging style, and if the use of webs as prey capture devices correlates with changes in body characteristics. Here we present the most extensive dataset to date of morphometric and ecological traits in spiders. We used this dataset to estimate the change in spider body sizes and shapes over deep time and to test if and how spider phenotypes are correlated with their behavioural ecology. We found that phylogenetic variation of most traits best fitted an Ornstein-Uhlenbeck model, which is a model of stabilizing selection. A prominent exception was body length, whose evolutionary dynamics were best explained with a Brownian Motion (free trait diffusion) model. This was most expressed in the araneoid clade (ecribellate orb-weaving spiders and allies) that showed bimodal trends towards either miniaturization or gigantism. Only few traits differed significantly between ecological guilds, most prominently leg length and thickness, and although a multivariate framework found general differences in traits among ecological guilds, it was not possible to unequivocally associate a set of morphometric traits with the relative ecological mode. Long, thin legs have often evolved with aerial webs and a hanging (suspended) locomotion style, but this trend is not general. Eye size and fang length did not differ between ecological guilds, rejecting the hypothesis that webs reduce the need for visual cue recognition and prey immobilization. For the inference of the ecology of species with unknown behaviours, we propose not to use morphometric traits, but rather consult (micro-)morphological characters, such as the presence of certain podal structures. These results suggest that, in contrast to insects, the evolution of body proportions in spiders is unusually stabilized, and ecological adaptations are dominantly realized by behavioural traits and extended phenotypes in this group of predators. This work demonstrates the power of combining recent advances in phylogenomics with trait-based approaches to better understand global functional diversity patterns through space and time.

opencc-zeroMar 2022View details →

The causes and ecological context of rapid morphological evolution in birds

Episodic pulses in morphological diversification are a prominent feature of evolutionary history, driven by factors that remain widely disputed. Resolving this question has proved challenging because comprehensive species-level data are generally unavailable at sufficient scale. Combining global phylogenetic and morphological data for birds, we show that pulses of diversification in lineages and traits tend to occur independently and in different contexts. Speciation pulses are preceded by greater differentiation in overall morphology and habitat niche, then followed by increased rates of beak evolution. Contrary to standard hypotheses, pulses of morphological diversification tend to be associated with habitat niche stability rather than adaptation to different diets and habitat types. These patterns suggest that the timing of diversification varies across traits according to their ecological function, and that pulses of morphological evolution may occur when successful lineages subdivide niche space within particular habitat types. Our results highlight the growing potential of functional trait data sets to refine macroevolutionary models.

opencc-by-4.0Jun 2022View details →

LPCA beach morphological evolution during October 2018 field experiment

LPCA beach morphological evolution during October 2018 field experiment. (a) Time exposure (timex) image consisting of averaged pixel intensity over the record length of the stack and (b) standard deviation image showing the amount of change in pixel intensity over the record length of the stack in order to highlight preferential wave breaking. The magenta line indicates the zero-elevation contour relative to NGF-IGN69. (c) Kalman-filtered cBathy video-derived bathymetries. Elevation contours are spaced at 0.5 m intervals relative to NGF-IGN69. (d) Bathymetric change maps; difference between cBathy-derived bathymetries (panel c) and the cBathy-derived bathymetry from 8/Oct/2018 07:30:00 GMT, where red colors indicate sand accretion and blue colors sand erosion with respect to 8 October 2018 video-derived bathymetry. (e) Offshore significant wave height Hs (red line; left axis), tidal elevation (blue line; right axis), 12-h-averaged alongshore wave energy flux Plong (green line; right axis) and 12-h-averaged angle of peak wave incidence θp (purple line; right axis) time series.

opencc-by-4.0Sep 2022View details →

Mechanisms of the Non-uniform Breach Morphology Evolution of Landslide Dams Composed of Unconsolidated Sediments During Overtopping Failure

Data that can be used to replicate and validate the results presented here are available through the upload file. Data access will be available upon request prior to official publication of this work.

opencc-zeroMay 2024View details →

Data from: Endocranial morphology of three early-diverging ceratopsians and implications for the behavior and the evolution of the endocast in ceratopsians

Ceratopsians underwent great changes including the shift of the locomotion mode, enlarged horns and frills, and increased body size. These changes are along with the changes in endocranial morphology and ecology such as the decrease of the flocculus, the hearing range, the olfactory ratio, and the Reptile Encephalization Quotient. However, the endocranial structures and associated ecology of the earliest ceratopsians are still unknown. Here, we reconstructed the endocasts of three early-diverging ceratopsians including the Late Jurassic Yinlong, and the Early Cretaceous Liaoceratops and Psittacosaurus. These ceratopsians display prominent flocculus, large and separate olfactory bulbs, long and high anterior semicircular canal, and long endosseous cochlear duct. Unlike Liaoceratops and Psittacosaurus, Yinlong exhibits relatively stocky semicircular canals and small flocculus. In Ceratopsia, the evolutional patterns of the endocast include the merging and narrowing of the olfactory bulbs, the disappearing flocculus, the reduction of the anterior semicircular canal, the increasing of the angle between two vertical semicircular canals, and the shortening of the cochlear duct. The endocranial structures suggest early-diverging ceratopsians had a high olfactory acuity and were adapted to hearing high frequencies, unlike the condition of late-diverging ceratopsians with lower olfactory acuity and hearing frequency. Reptile Encephalization Quotient suggests that Yinlong and Psittacosaurus were more encephalized than most extant reptiles and late-diverging ceratopsians. The angle of the lateral semicircular canal suggests that heads in ceratopsians display a transition from an upward posture to a downward posture. The relatively upward head posture indicates that early-diverging ceratopsians could feed more selectively such as to eat some leaves.

opencc-zeroJun 2024View details →

Data from: Locomotory and morphological evolution of the earliest Silurian graptolite (Demirastrites) selected by hydrodynamics

Interpretation of the locomotion for biostratigraphic important graptolite taxa is rare and rendered problematic due to their lack of close modern analogues and soft tissues. In this study, based on well-preserved specimens of the early Silurian low-helical spiral Demirastrites Eisel, we reconstructed three-dimensional (3D) Demirastrites models and simulated their locomotion by using computational fluid dynamics. Hydrodynamic properties (outer-wall pressure fields and velocity fields) were obtained and used to test the prevailing hypothesis that the Silurian low helical spiral graptolite Demirastrites could rotate in seawater. The Demirastrites models kept rotating at different velocities in the simulation field, which helped to counteract the impact of the water current and achieve stability. During rotation, higher velocity fields could be observed near the thecal apertures, which meant better access to more nutrient particles in the sea water. Our simulation thus confirmed the rotating locomotory pattern of the Silurian low conical graptolite Demirastrites for the purpose of better feeding efficiency and turbarium stability. Moreover, we analysed how the evolution of structural innovations, such as the density and width of thecae and the curvature angle of the rhabdosome within the recovered geological lineages of Demirastrites, were influenced and selected by hydrodynamics. The results showed that Demirastrites lineages evolved towards increased stability and higher rotation velocity. Our study highlights the importance of hydrodynamic constraints serving as hidden abiotic factors shaping the evolution of planktonic graptolites.

Fig. 4b in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 4b. Tillomorphites elachys (Martins & Galileo, 2013) n. comb., Paratype.

Fig. 3c Tillomorphites spinipes n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 3c Tillomorphites spinipes n. sp., Holotype, particular.

Fig. 3b Tillomorphites spinipes n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 3b Tillomorphites spinipes n. sp., Holotype, ventral view.

Fig. 3a Tillomorphites spinipes n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 3a Tillomorphites spinipes n. sp., Holotype, dorsal view.

Fig. 2 d. Tillomorphites otiliae n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 2 d. Tillomorphites otiliae n. sp., Holotype, colour reconstruction.

Fig. 2b. Tillomorphites otiliae n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 2b. Tillomorphites otiliae n. sp., Paratype.

Fig. 2a. Tillomorphites otiliae n in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 2a. Tillomorphites otiliae n. sp., Holotype.

Fig. 1a. Tillomorphites robustus Vitali, 2011 in Two new fossil species of Tillomorphites Vitali (Coleoptera: Cerambycidae) and remarks on the morphological evolution, mimicry, biogeography and phylogeny of the tribe Tillomorphini

Fig. 1a. Tillomorphites robustus Vitali, 2011, Holotype.