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4,753 results for “SHAPE”
Data from: Latitudinal environmental niches and riverine barriers shaped the phylogeography of the central Chilean endemic Dioscorea humilis (Dioscoreaceae)
The effects of Pleistocene glaciations and geographical barriers on the phylogeographic patterns of lowland plant species in Mediterranean-climate areas of Central Chile are poorly understood. We used Dioscorea humilis (Dioscoreaceae), a dioecious geophyte extending 530 km from the Valparaíso to the Bío-Bío Regions, as a case study to disentangle the spatio-temporal evolution of populations in conjunction with latitudinal environmental changes since the Last Inter-Glacial (LIG) to the present. We used nuclear microsatellite loci, chloroplast (cpDNA) sequences and environmental niche modelling (ENM) to construct current and past scenarios from bioclimatic and geographical variables and to infer the evolutionary history of the taxa. We found strong genetic differentiation at nuclear microsatellite loci between the two subspecies of D. humilis, probably predating the LIG. Bayesian analyses of population structure revealed strong genetic differentiation of the widespread D. humilis subsp. humilis into northern and southern population groups, separated by the Maipo river. ENM revealed that the ecological niche differentiation of both groups have been maintained up to present times although their respective geographical distributions apparently fluctuated in concert with the climatic oscillations of the Last Glacial Maximum (LGM) and the Holocene. Genetic data revealed signatures of eastern and western postglacial expansion of the northern populations from the central Chilean depression, whereas the southern ones experienced a rapid southward expansion after the LGM. This study describes the complex evolutionary histories of lowland Mediterranean Chilean plants mediated by the summed effects of spatial isolation caused by riverine geographical barriers and the climatic changes of the Quaternary.
Data from: Reproductive character displacement shapes a spatially structured petal color polymorphism in Leavenworthia stylosa
Character displacement is a potentially important process driving trait evolution and species diversification. Floral traits may experience character displacement in response to pollinator-mediated competition (ecological character displacement) or the risk of forming hybrids with reduced fitness (reproductive character displacement). We test these and alternative hypotheses to explain a yellow-white petal color polymorphism in Leavenworthia stylosa, where yellow morphs are spatially associated with a white-petaled congener (L. exigua) that produces hybrids with complete pollen sterility. A reciprocal transplant experiment found limited evidence of local adaptation of yellow color morphs via increased survival and seed set. Pollinator observations revealed that Leavenworthia attract various pollinators that generally favor white petals and exhibit color constancy. Pollen limitation experiments showed that yellow petals do not alleviate competition for pollination. Interspecific pollinator movements were infrequent and low hybridization rates (∼0.40% - 0.85%) were found in each morph, with natural rates likely being lower. Regardless, hybridization rates were significantly higher in white morphs of L. stylosa, yielding a small selection coefficient of s = 0.0042 against this phenotype in sympatry with L. exigua. These results provide support for reproductive character displacement as a mechanism contributing to the pattern of petal color polymorphism in L. stylosa.
Evolutionary constraints and adaptation shape the size and colour of rain forest fruits and flowers at continental scale
<p><span><b>Aim:</b> Large-scale patterns in flower and fruit traits provide critical insights into selection processes and the evolutionary history of plant lineages. To isolate and identify the role of selective pressures including different plant-animal interactions, and the factors driving trait evolution, we investigate convergence and divergence between flower and fruit traits in shared environments.</span></p> <p><span><b>Location:</b> Australia to Southeast Asia.</span></p> <p><span><b>Time period: </b>Eocene (~45 My) to Present.</span></p> <p><span><b>Major taxa studied:</b> Woody angiosperm rainforest species (2248 species, 133 families).</span></p> <p><span><b>Methods: </b>Using a continental scale data set for all woody angiosperm species in the Australian rainforest (1816 free-standing and 432 climbing species) we compare the colour and size of fleshy fruits and flowers in relation to life form (trees/shrubs and vines), species biogeographic histories and origins (Sunda vs<i>.</i> Sahul), and bio-regional distributions.</span></p> <p><span><b>Results</b><b>:</b> Fleshy fruits in the Australian rainforest are mostly small, with a diversity of colours (<30mm; 81%), while flowers are mostly small (<10mm; 65%) and whitish (~80%). Compared to trees and shrubs, climbing species showed a higher proportion of red fleshy fruits, and large coloured flowers. Small whitish flowers were dominant across lineages from different biogeographic origins (Sunda-Sahul) and geographical regions, while both small and large fleshy fruits retained a range of disperser attractant colours.</span></p> <p><span><b>Main conclusions:</b> Continental scale size and colour characteristics of flowers and fleshy fruits differed despite sharing environments with similar abiotic selective pressures through time. Plant-animal interactions including pollination and dispersal likely mediate different evolutionary outcomes for plant traits, and reflect both adaptation and evolutionary constraints.</span></p>
Data from: Body size and allometric shape variation in the molly Poecilia vivipara along a gradient of salinity and predation
Background: Phenotypic diversity among populations may result from divergent natural selection acting directly on traits or via correlated responses to changes in other traits. One of the most frequent patterns of correlated response is the proportional change in the dimensions of anatomical traits associated with changes in growth or absolute size, known as allometry. Livebearing fishes subject to predation gradients have been shown to repeatedly evolve larger caudal peduncles and smaller cranial regions under high predation regimes. Poecilia vivipara is a livebearing fish commonly found in coastal lagoons in the north of the state of Rio de Janeiro, Brazil. Similar to what is observed in other predation gradients, lagoons inhabited by P. vivipara vary in the presence of piscivorous fishes; contrary to other poeciliid systems, populations of P. vivipara vary greatly in body size, which opens the possibility of strong allometric effects on shape variation. Here we investigated body shape diversification among six populations of P. vivipara along a predation gradient and its relationship with allometric trajectories within and among populations.ResultsWe found substantial body size variation and correlated shape changes among populations. Multivariate regression analysis showed that size variation among populations accounted for 66% of shape variation in females and 38% in males, suggesting that size is the most important dimension underlying shape variation among populations of P. vivipara in this system. Changes in the relative sizes of the caudal peduncle and cranial regions were only partly in line with predictions from divergent natural selection associated with predation regime.ConclusionsOur results suggest the possibility that adaptive shape variation among populations has been partly constrained by allometry in P. vivipara. Processes governing body size changes are therefore important in the diversification of this species. We conclude that in species characterized by substantial among-population differences in body size, ignoring allometric effects when investigating divergent natural selection?s role in phenotypic diversification might not be warranted.
Data from: Environment and evolutionary history shape phylogenetic turnover in European tetrapods
Phylogenetic turnover quantifies the evolutionary distance among species assemblages and is central to understanding the main drivers shaping biodiversity. It is affected both by geographic and environmental distance between sites. Therefore, analyzing phylogenetic turnover in environmental space requires removing the effect of geographic distance. Here, we apply a novel approach by deciphering phylogenetic turnover of European tetrapods in environmental space after removing geographic land distance effects. We demonstrate that phylogenetic turnover is strongly structured in environmental space, particularly in ectothermic tetrapods, and is well explained by macroecological characteristics such as niche size, species richness and relative phylogenetic diversity. In ectotherms, rather recent evolutionary processes were important in structuring phylogenetic turnover along environmental gradients. In contrast, early evolutionary processes had already shaped the current structure of phylogenetic turnover in endotherms. Our approach enables the disentangling of the idiosyncrasies of evolutionary processes such as the degree of niche conservatism and diversification rates in structuring biodiversity.
Divergent neurogenomic responses shape social learning of both personality and mate preference
<p>Behavior plays a fundamental role in shaping the origin and fate of species. Mating decisions can act to promote or restrict gene flow, as can personality traits that influence dispersal and niche use. Mate choice and personality are often both learned and therefore influenced by an individual's social environment throughout development. Likewise, the molecular pathways that shape these behaviors may also be co-expressed. In this study on swordtail fish (<i>Xiphophorus birchmanni</i>), we show that female mating preferences for species-typical pheromone cues are entirely dependent on social experience with adult males. Experience with adults also shapes development along the shy-bold personality axis, with shy behaviors arising from exposure to risk-averse heterospecifics as a potential stress-coping strategy. In maturing females, conspecific exposure results in a strong upregulation of olfaction and vision genes compared to heterospecific exposure, as well as immune response genes previously linked to anxiety, learning and memory. Conversely, heterospecific exposure involves an increased expression of genes important for neurogenesis, synaptic plasticity and social decision-making. We identify subsets of genes within the social decision-making network and with known stress-coping roles that may be directly coupled to the olfactory processes females rely on for social communication. Based on these results, we conclude that the social environment affects the neurogenomic trajectory through which socially-sensitive behaviors are learned, resulting in adult phenotypes adapted for specific social groupings.</p>
Data from: Small-scale spatial variation in infection risk shapes the evolution of a Borrelia resistance gene in wild rodents
Spatial variation in pathogen-mediated selection is predicted to influence the evolutionary trajectory of host populations and lead to spatial variation in their immunogenetic composition. However, to date few studies have been able to directly link small-scale spatial variation in infection risk to host immune gene evolution in natural, non-human populations. Here we use a natural rodent-Borrelia system to test for associations between landscape-level spatial variation in Borrelia infection risk along replicated elevational gradients in the Swiss Alps and Toll-like receptor 2 (TLR2) evolution, a candidate gene for Borrelia resistance, across bank vole (Myodes glareolus) populations. We found that Borrelia infection risk (i.e. the product of Borrelia prevalence in questing ticks and the average tick load of voles at a sampling site) was spatially variable and significantly negatively associated with elevation. Across sampling sites, Borrelia prevalence in bank voles was significantly positively associated with Borrelia infection risk along the elevational clines. We observed a significant association between naturally occurring TLR2 polymorphisms in hosts and their Borrelia infection status. The TLR2 variant associated with a reduced likelihood of Borrelia infection was most common in rodent populations at lower elevations that face a high Borrelia infection risk, and its frequency changed in accordance with the change in Borrelia infection risk along the elevational clines. These results suggest that small-scale spatial variation in parasite-mediated selection affects the immunogenetic composition of natural host populations, providing a striking example that the microbial environment shapes the evolution of the host's immune system in the wild.
Data from: Long livestock farming history and human landscape shaping revealed by lake sediment DNA
The reconstruction of human-driven, Earth-shaping dynamics is important for understanding past human/environment interactions and for helping human societies that currently face global changes. However, it is often challenging to distinguish the effects of the climate from human activities on environmental changes. Here we evaluate an approach based on DNA metabarcoding used on lake sediments to provide the first high-resolution reconstruction of plant cover and livestock farming history since the Neolithic Period. By comparing these data with a previous reconstruction of erosive event frequency, we show that the most intense erosion period was caused by deforestation and overgrazing by sheep and cowherds during the Late Iron Age and Roman Period. Tracking plants and domestic mammals using lake sediment DNA (lake sedDNA) is a new, promising method for tracing past human practices, and it provides a new outlook of the effects of anthropogenic factors on landscape-scale changes.
Data from: Feeding ecology is the primary driver of beak shape diversification in waterfowl
The diversity of beak shapes among birds is often assumed to be largely the result of adaptations to different feeding behaviors and diets. However, this assumption has only been tested for a small subset of avian diversity, primarily within the order Passeriformes. Moreover, given the role of the beak in behaviors other than feeding and given that most previously identified beak-feeding associations concern beak size rather than shape, it remains unclear how much of beak shape diversity is explained by feeding ecology and what functional explanations account for these differences in shape. I quantified the association between beak shape and feeding ecology for 42 species in the bird order Anseriformes (waterfowl) using 3D curvature of the upper beak collected from museum specimens and continuous dietary data compiled from the literature. I also tested whether leverage or stress resistance of the beak explains the association between beak shape and feeding ecology. Diet is strongly and significantly correlated with beak shape in waterfowl. An ancestral beak shape reconstruction and the reconstructed diet of the anseriform fossil Presbyornis both support filter-feeding as ancestral for most waterfowl, followed by multiple, significantly convergent transitions from a duck-like beak toward a more goose-like beak. The evolution of a more goose-like beak is associated with increased consumption of leaves, decreased consumption of invertebrates, and an increase in mechanical advantage of the beak. Moreover, no association was identified between size (measured as either beak size or body mass) and feeding ecology nor between size and beak shape. These results demonstrate that feeding ecology has acted as the primary selective force in the diversification of waterfowl beak shapes, including the convergent originations of geese. Thus, rapid and convergent adaptation of the beak to feeding is not limited to passerines nor is it limited to size-correlated shape changes. The positive evolutionary correlation between mechanical advantage and herbivory shows that lever mechanics can explain the functional evolution of the kinetic upper beak in birds. These results also suggest that functions of the beak other than feeding may play a minor role in explaining overall beak shape diversity.
Data from: Recent population decline and selection shape diversity of taxol-related genes
Taxanes are defensive metabolites produced by Taxus species (yews) and used in anticancer therapies. Despite their medical interest, patterns of natural diversity in taxane related genes are unknown. We examined variation at five main taxol-related genes of T. baccata in the Iberian Peninsula, a region where unique yew genetic resources are endangered. We looked at several gene features and applied complementary neutrality tests, including diversity/divergence tests, tests solely based on site-frequency spectrum and Zeng's compound tests. To account for specific demography, microsatellite data were used to infer historical changes in population size based on an Approximate Bayesian Computation (ABC) approach. Polymorphism-divergence tests pointed to positive selection for genes TBT and TAT, and balancing selection for DBAT. In addition, neutrality tests based on site-frequency spectrum found that while a recent reduction in population size may explain most of statistics' values, selection may still be in action in genes TBT and DBAT, at least in some populations. Molecular signatures on taxol genes suggest the action of frequent selective waves with different direction or intensity, possibly related to varying adaptive pressures produced by the host-enemy co-evolution on defense-related genes. Such natural selection processes may have produced taxane variants still undiscovered.
Data from: Species Selection Regime and Phylogenetic Tree Shape
<p>Species selection, the effect of heritable traits in generating between-lineage diversification rate differences, provides a valuable conceptual framework for understanding the relationship between traits, diversification and phylogenetic tree shape. An important challenge, however, is that the nature of real diversification landscapes – curves or surfaces which describe the propensity of species-level lineages to diversify as a function of one or more traits – remains poorly understood. Here we present a novel, time-stratified extension of the QuaSSE model in which speciation/extinction rate is specified as a static or temporally-shifting Gaussian or skewed-Gaussian function of the diversification trait. We then use simulations to show that the generally imbalanced nature of real phylogenetic trees, as well as their generally greater-than-expected frequency of deep branching events, are typical outcomes when diversification is treated as a dynamic, trait-dependent process. Focusing on four basic models (Gaussian-speciation with and without background extinction; skewed-speciation; Gaussian-extinction), we also show that particular features of the species selection regime produce distinct tree shape signatures and that, consequently, a combination of tree shape metrics has the potential to reveal the species selection regime under which a particular lineage diversified. We evaluate this idea empirically by comparing the phylogenetic trees of plant lineages diversifying within climatically- and geologically-stable environments of the Greater Cape Floristic Region, with those of lineages diversifying in environments that have experienced major change through the Late Miocene-Pliocene. Consistent with our expectations, the trees of lineages diversifying in a dynamic context are less balanced, show a greater concentration of branching events close to the present, and display stronger diversification rate-trait correlations. We suggest that species selection plays an important role in shaping phylogenetic trees but recognize the need for an explicit probabilistic framework within which to assess the likelihoods of alternative diversification scenarios as explanations of a particular tree shape.</p>
Data from: Strong maternal fidelity and natal philopatry shape genetic structure in North Pacfic humpback whales
We quantified the relative influence of maternal fidelity to feeding grounds and natal fidelity to breeding grounds in humpback whales based on an ocean-wide survey of mitochondrial (mt) DNA diversity in the North Pacific. For 2,193 biopsy samples collected from whales in 10 feeding regions and 8 breeding regions during the winter and summer of 2004 to 2006, we first used microsatellite genotyping (average, 9.5 loci) to identify replicate samples. From sequences of the mtDNA control region (500 bp) we identified 28 unique haplotypes from 30 variable sites. Haplotype frequencies differed markedly among feeding regions (overall FST = 0.121, PhiST = 0.178, p < 0.0001), supporting previous evidence of strong maternal fidelity. Haplotype frequencies also differed markedly among breeding regions (overall FST = 0.093, PhiST = 0.106, p < 0.0001), providing evidence of strong natal fidelity. Although sex-biased dispersal was not evident, differentiation of microsatellite allele frequencies was weak compared to differentiation of mtDNA haplotypes, suggesting male-biased gene flow. Feeding and breeding regions showed significant differences in haplotype frequencies, even for regions known to be strongly connected by patterns of individual migration. Thus, the influence of migratory fidelity seems to operate somewhat independently on feeding and breeding grounds over an evolutionary time scale. This results in a complex population structure and the potential to define multiple units to conserve in either seasonal habitat.
Class-A penicillin binding proteins do not contribute to cell shape but repair cell-wall defects
Cell shape and cell-envelope integrity of bacteria are determined by the peptidoglycan cell wall. In rod-shaped Escherichia coli, two conserved sets of machinery are essential for cell-wall insertion in the cylindrical part of the cell: the Rod complex and the class-A penicillin-binding proteins (aPBPs). While the Rod complex governs rod-like cell shape, aPBP function is less well understood. aPBPs were previously hypothesized to either work in concert with the Rod complex or to independently repair cell-wall defects. First, we demonstrate through modulation of enzyme levels that aPBPs do not contribute to rod-like cell shape but are required for mechanical stability, supporting their independent activity. By combining measurements of cell-wall stiffness, cell-wall insertion, and PBP1b motion at the single-molecule level, we then present evidence that PBP1b, the major aPBP, contributes to cell-wall integrity by repairing cell wall defects.
Data from: Vertical canopy gradient shaping the stratification of leaf-chewer-parasitoid interactions in a temperate forest
Knowledge about herbivores and their parasitoids in forest canopies remains limited, despite their diversity and ecological importance. Thus, it is important to understand the factors that shape the herbivore–parasitoid community structure, particularly the effect of vertical gradient. We investigated a quantitative community dataset of exposed and semiconcealed leaf‐chewing larvae and their parasitoids along a vertical canopy gradient in a temperate forest. We sampled target insects using an elevated work platform in a 0.2 ha broadleaf deciduous forest plot in the Czech Republic. We analyzed the effect of vertical position among three canopy levels (first [lowest], second [middle], and third [highest]) and tree species on community descriptors (density, diversity, and parasitism rate) and food web structure. We also analyzed vertical patterns in density and parasitism rate between exposed and semiconcealed hosts, and the vertical preference of the most abundant parasitoid taxa in relation to their host specificity. Tree species was an important determinant of all community descriptors and food web structure. Insect density and diversity varied with the vertical gradient, but was only significant for hosts. Both host guilds were most abundant in the second level, but only the density of exposed hosts declined in the third level. Parasitism rate decreased from the first to third level. The overall parasitism rate did not differ between guilds, but semiconcealed hosts suffered lower parasitism in the third level. Less host‐specific taxa (Ichneumonidae, Braconidae) operated more frequently lower in the canopy, whereas more host‐specific Tachinidae followed their host distribution. The most host‐specific Chalcidoidea preferred the third level. Vertical stratification of insect density, diversity, and parasitism rate was most pronounced in the tallest tree species. Therefore, our study contradicts the general paradigm of weak arthropod stratification in temperate forest canopies. However, in the network structure, vertical variation might be superseded by variation among tree species.
Data from: Spatial memory shapes migration and its benefits: evidence from a large herbivore
From fine-scale foraging to broad-scale migration, animal movement is shaped by the distribution of resources. There is mounting evidence, however, that learning and memory also guide movement. Although migratory mammals commonly track resource waves, how resource tracking and memory guide long-distance migration has not been reconciled. We examined these hypotheses using movement data from four populations of migratory mule deer (n=91). Spatial memory had an extraordinary influence on migration, affecting movement 2–28 times more strongly than tracking spring green-up or autumn snow depth. Importantly, with only an ability to track resources, simulated deer were unable to recreate empirical migratory routes. In contrast, simulated deer with memory of empirical routes, used those routes and obtained higher foraging benefits. For migratory terrestrial mammals, spatial memory provides knowledge of where seasonal ranges and migratory routes exist, while resource tracking determines when to beneficially move within those areas.
Data from: What shapes cerambycid beetle communities in a tropical forest mosaic? Assessing the effects of host tree identity, forest structure, and vertical stratification
Due to anthropogenic activities, tropical rain forests face many challenges in sustaining biodiversity and maintaining global climates. This study explores how forest successional stage, tree composition, and stratum affect communities of saproxylic cerambycid beetles—concealed feeders that play important roles in forest nutrient cycling. Forty trees in five families (Fabaceae, Lecythidaceae, Malvaceae, Moraceae, and Sapotaceae) were sampled in a mosaic of old-growth and secondary forest on the Osa Peninsula, Costa Rica. Bait branches yielded 3549 cerambycid individuals in 49 species. Species richness was almost identical in old-growth and secondary forest, and both yielded specialists, but abundance was higher in old-growth forest. Overall community structure was most strongly influenced by host plant species; within most plant families it was also impacted by forest successional status. Moraceae was the exception, presumably because the focal tree species was abundant in both old-growth and secondary forest. Several host and old-growth specialist species reached high densities within patches of old-growth forest, but seldom colonized apparently suitable trees within secondary forest. This suggests that even small areas of old-growth forest can act as refuges, but that secondary forest may act as a barrier to dispersal. The vulnerability of specialized saproxylic insects to land use change will be linked to the ability of their preferred hosts to disperse to and persist in successional habitats; rearing studies may provide the most accurate method to monitor community changes over time.
Data from: Landscape simplification shapes pathogen prevalence in plant-pollinator networks
Species interaction networks, which play an important role in determining pathogen transmission and spread in ecological communities, can shift in response to agricultural landscape simplification. However, we know surprisingly little about how landscape simplification-driven changes in network structure impact epidemiological patterns. Here, we combine mathematical modeling and data from eleven bipartite plant-pollinator networks observed along a landscape simplification gradient to elucidate how changes in network structure shape disease dynamics. Our empirical data show that landscape simplification reduces pathogen prevalence in bee communities via increased diet breadth of the dominant species. Furthermore, our empirical data and theoretical model indicate that increased connectance reduces the likelihood of a disease outbreak and decreases variance in prevalence among bee species in the community, resulting in a dilution effect. Because infectious diseases are implicated in pollinator declines worldwide, a better understanding of how land use change impacts species interactions is therefore critical for conserving pollinator health.
Estimating phylogenies from shape and similar multidimensional data: why it is not reliable
In recent years, there has been controversy whether multidimensional data such as geometric morphometric data or information on gene expression can be used for estimating phylogenies. This study uses simulations of evolution in multidimensional phenotype spaces to address this question and to identify specific factors that are important for answering it. Most of the simulations use phylogenies with four taxa, so that there are just three possible unrooted trees and the effect of different combinations of branch lengths can be studied systematically. In a comparison of methods, squared-change parsimony performed similarly well as maximum likelihood, and both methods outperformed Wagner and Euclidean parsimony, neighbor-joining and UPGMA. Under an evolutionary model of isotropic Brownian motion, phylogeny can be estimated reliably if dimensionality is high, even with relatively unfavorable combinations of branch lengths. By contrast, if there is phenotypic integration such that most variation is concentrated in one or a few dimensions, the reliability of phylogenetic estimates is severely reduced. Evolutionary models with stabilizing selection also produce highly unreliable estimates, which are little better than picking a phylogenetic tree at random. To examine how these results apply to phylogenies with more than four taxa, we conducted further simulations with up to eight taxa, which indicated that the effects of dimensionality and phenotypic integration extend to more than four taxa, and that convergence among internal nodes may produce additional complications specifically for greater numbers of taxa. Overall, the simulations suggest that multidimensional data, under evolutionary models that are plausible for biological data, do not produce reliable estimates of phylogeny.
Data from: Constrained body shape among highly genetically divergent allopatric lineages of the supralittoral isopod Ligia occidentalis (Oniscidea)
Multiple highly divergent lineages have been identified within Ligia occidentalis sensu lato, a rocky supralittoral isopod distributed along a ~3000 km latitudinal gradient that encompasses several proposed marine biogeographic provinces and ecoregions in the eastern Pacific. Highly divergent lineages have nonoverlapping geographic distributions, with distributional limits that generally correspond with sharp environmental changes. Crossbreeding experiments suggest postmating reproductive barriers exist among some of them, and surveys of mitochondrial and nuclear gene markers do not show evidence of hybridization. Populations are highly isolated, some of which appear to be very small; thus, the effects of drift are expected to reduce the efficiency of selection. Large genetic divergences among lineages, marked environmental differences in their ranges, reproductive isolation, and/or high isolation of populations may have resulted in morphological differences in L. occidentalis, not detected yet by traditional taxonomy. We used landmark-based geometric morphometric analyses to test for differences in body shape among highly divergent lineages of L. occidentalis, and among populations within these lineages. We analyzed a total of 492 individuals from 53 coastal localities from the southern California Bight to Central Mexico, including the Gulf of California. We conducted discriminant function analyses (DFAs) on body shape morphometrics to assess morphological variation among genetically differentiated lineages and their populations. We also tested for associations between phylogeny and morphological variation, and whether genetic divergence is correlated to multivariate morphological divergence. We detected significant differences in body shape among highly divergent lineages, and among populations within these lineages. Nonetheless, neither lineages nor populations can be discriminated on the basis of body shape, because correct classification rates of cross-validated DFAs were low. Genetic distance and phylogeny had weak to no effect on body shape variation. The supralittoral environment appears to exert strong stabilizing selection and/or strong functional constraints on body shape in L. occidentalis, thereby leading to morphological stasis in this isopod.
Data from: Do convergent ecomorphs evolve through convergent morphological pathways? Cranial shape evolution in fossil hyaenids and borophagine canids (Carnivora, Mammalia)
Cases of convergent evolution, particularly within ecomorphological contexts, are instructive in identifying universally adaptive morphological features across clades. Tracing of evolutionary pathways by which ecomorphological convergence takes place can further reveal mechanisms of adaptation, which may be strongly influenced by phylogeny. Ecomorphologies of carnivorous mammals represent some of the most outstanding cases of convergent evolution in the Cenozoic radiation of mammals. This study examined patterns of cranial shape change in the dog (Canidae) and hyena (Hyaenidae) families, in order to compare the evolutionary pathways that led to the independent specialization of bone-cracking hypercarnivores within each clade. Geometric morphometrics analyses of cranial shape in fossil hyaenids and borophagine canids provided evidence for deep-time convergence in morphological pathways toward the independent evolution of derived bone-crackers. Both clades contained stem members with plesiomorphic generalist/omnivore cranial shapes, which evolved into doglike species along parallel pathways of shape change. The evolution of specialized bone-crackers from these doglike forms, however, continued under the constraint of a full cheek dentition and restriction on rostrum length reduction in canids, but not hyaenids. Functionally, phylogenetic constraint may have limited borophagine canids to crack bones principally with their carnassial instead of the third premolar as in hyaenids, but other cranial shape changes associated with durophagy nevertheless evolved in parallel in the two lineages. Size allometry was not a major factor in cranial shape evolution in either lineage, supporting the interpretation of functional demands as drivers for the observed convergence. The comparison between borophagines and hyaenids showed that differential effects of alternative functional "solutions" that arise during morphological evolution may be multiplied with processes of the "macroevolutionary ratchet" already in place to further limit the evolutionary pathways available to specialized lineages.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.