Evolution of dentition in salamanders: relative roles of phylogeny and diet

Despite being widely regarded as generalist predators, amphibians exhibit a diversity of tooth shapes and dentition patterns, which may indicate the influence of dietary specialization on the evolution of tooth morphology. Very few studies have analysed the relationship between tooth morphology and diet (i.e., prey items) in amphibians, and those existing studies are highly speculative. We investigated the evolution of salamander teeth and the relationship between tooth morphology and diet in a phylogenetically independent fashion. We used a phylogeny of 23 species of salamander representing three families (Ambystomatidae, Plethodontidae, and Salamandridae) to, first, analyse the divergence of tooth morphology and its relationship to phylogeny and, second, to analyse the relationship between tooth morphology and diet diversity. We used electron scanning microscopy and a statistical comparative approach using Spatial Evolutionary and Ecological Analysis (SEEVA) and phylogenetic generalized least‐squares regression in R. Our results indicated significant divergence in tooth morphology at major phylogenetic splits. Moreover, there was a significant, phylogenetically independent relationship between tooth morphology and diet diversity. The relationship between diet and tooth morphology indicates not only a reflection of phylogenetic history, but also a degree of dietary specialization, indicating that evolution in tooth morphology has had an adaptive aspect in relation to salamander diet.     

Evolutionary history shapes patterns of mutualistic benefit in Acacia–rhizobial interactions

The ecological and evolutionary factors that drive the emergence and maintenance of variation in mutualistic benefit (i.e., the benefits provided by one partner to another) in mutualistic symbioses are not well understood. In this study, we evaluated the role that host and symbiont phylogeny might play in determining patterns of mutualistic benefit for interactions among nine species of Acacia and 31 strains of nitrogen‐fixing rhizobial bacteria. Using phylogenetic comparative methods we compared patterns of variation in mutualistic benefit (host response to inoculation) to rhizobial phylogenies constructed from housekeeping and symbiosis genes; and a multigene host phylogeny. We found widespread genotype‐by‐genotype variation in patterns of plant growth. A relatively large component of this variation (21–28%) was strongly influenced by the interacting evolutionary histories of both partners, such that phylogenetically similar host species had similar growth responses when inoculated with phylogenetically similar rhizobia. We also found a relatively large nonphylogenetic effect for the average mutualistic benefit provided by rhizobia to plants, such that phylogenetic relatedness did not predict the overall benefit provided by rhizobia across all hosts. We conclude that phylogenetic relatedness should frequently predict patterns of mutualistic benefit in acacia‐rhizobial mutualistic interactions; but that some mutualistic traits also evolve independently of the phylogenies.     

Are plumatellid statoblasts in freshwater bryozoans phylogenetically informative?

Morphological characters of statoblasts (including floatoblasts and sessoblasts) in freshwater bryozoans have been important in phylactolaemate systematics and identification in that older phylogenetic hypotheses relied heavily on statoblast morphology. To assess the reliability of statoblast characters in drawing conclusions about phylogeny, we examined the phylogenetic distribution of metric and proportional floatoblast characters, floatoblast symmetry, and floatoblast and sessoblast microsculpture in Plumatellidae, the largest family of phylactolaemates, in the context of molecular phylogenetic reconstructions based on nucleotide sequences of parts of the mitochondrial 12S rRNA, 16S rRNA, and cytochrome b (cytb) genes. Adding cytb sequences to a previous phylogeny based on 12S and 16S increased support only for a node including Plumatella vaihiriae in the P. repens clade. Characters of gross floatoblast morphology were generally not phylogenetically informative individually, but collectively discriminated among members of three relatively well-supported clades that were analyzed as pre-defined groups in a discriminant analysis. Two characters of floatoblast microsculpture (reticulation and hypertubercles) were restricted to particular clades; other characters (e.g., villi) were clearly convergent. In nine of 11 cases, fenestral microsculpture was identical or partly correlated between the floatoblast and sessoblast of a species. Overall, our results indicate that statoblast morphology is not highly phylogenetically constrained.     

番荔枝科研究35.Guatteria类群和有关属的系统发育

Guatteria类群由4个新热带的属组成,即Guatteria,Guatteriopsis,Guatteriella和Heteropetalum。不同的作者基于不同的证据得出的它在番荔枝中的地位各不相同。基于宏观和微观的形态特征,对该类群进行了表型和分支分析。分支分析表明,所研究属的系统发育分支方式仅由极少数共同衍征支持,同型现象非常明显,所获得的唯一的最简约分支图可分为两个基本部分,即一个(假)合生心皮分支和一个离生心皮grade。在表征聚类图和主成分分析的三维构象图中同样可以区分出离生心皮和(假)合生心皮两个表征群,表征分析表明Guatteria类群处在其它离生心皮类和(假)合生心皮类的中间位置。然而分支分析表明Guatteria类群与番荔枝科中最进化的(假)合生心皮类有姊妹群关系。Guatteria类群是离生心皮类中最进化的一类。番荔枝科中离生心皮类和(假)合生心皮类在漫长的进化过程中经历了强烈的形态分化而显示出极大的形态差异,然而在系统发育上它们可以通过Guatteria类群作为纽带而联系起来。     

Specialization clines in the pollination systems of agaves (Agavaceae) and columnar cacti (Cactaceae): A phylogenetically controlled meta-analysis

The biogeography of plant-animal interactions is a novel topic on which many disciplines converge (e.g., reproductive biology, biogeography, and evolutionary biology). Narrative reviews have indicated that tropical columnar cacti and agaves have highly specialized pollination systems, while extratropical species have generalized systems. However, this dichotomy has never been quantitatively tested. We tested this hypothesis using traditional and phylogenetically informed meta-analysis. Three effect sizes were estimated from the literature: diurnal, nocturnal, and hand cross-pollination (an indicator of pollen limitation). Columnar cactus pollination systems ranged from purely bat-pollinated in the tropics to generalized pollination, with diurnal visitors as effective as nocturnal visitors in extratropical regions; even when phylogenetic relatedness among species is taken into account. Metaregressions identified a latitudinal increase in pollen limitation in columnar cacti, but this increase was not significant after correcting for phylogeny. The currently available data for agaves do not support any latitudinal trend. Nectar production of columnar cacti varied with latitude. Although this variation is positively correlated with pollination by diurnal visitors, it is influenced by phylogeny. The degree of specificity in the pollination systems of columnar cacti is heavily influenced by ecological factors and has a predictable geographic pattern.     

Phylogenetic and morphological relationships between nonvolant small mammals reveal assembly processes at different spatial scales

The relative roles of historical processes, environmental filtering, and ecological interactions in the organization of species assemblages vary depending on the spatial scale. We evaluated the phylogenetic and morphological relationships between species and individuals (i.e., inter‐ and intraspecific variability) of Neotropical nonvolant small mammals coexisting in grassland‐forest ecotones, in landscapes and in regions, that is, three different scales. We used a phylogenetic tree to infer evolutionary relationships, and morphological traits as indicators of performance and niche similarities between species and individuals. Subsequently, we applied phylogenetic and morphologic indexes of diversity and distance between species to evaluate small mammal assemblage structures on the three scales. The results indicated a repulsion pattern near forest edges, showing that phylogenetically similar species coexisted less often than expected by chance. The strategies for niche differentiation might explain the phylogenetic repulsion observed at the edge. Phylogenetic and morphological clustering in the grassland and at the forest interior indicated the coexistence of closely related and ecologically similar species and individuals. Coexistence patterns were similar whether species‐trait values or individual values were used. At the landscape and regional scales, assemblages showed a predominant pattern of phylogenetic and morphological clustering. Environmental filters influenced the coexistence patterns at three scales, showing the importance of phylogenetically conserved ecological tolerances in enabling taxa co‐occurrence. Evidence of phylogenetic repulsion in one region indicated that other processes beyond environmental filtering are important for community assembly at broad scales. Finally, ecological interactions and environmental filtering seemed important at the local scale, while environmental filtering and historical colonization seemed important for community assembly at broader scales.     

Effects of ornamentation and phylogeny on the evolution of wing shape in stalk‐eyed flies (Diopsidae)

Exaggerated male ornaments are predicted to be costly to their bearers, but these negative effects may be offset by the correlated evolution of compensatory traits. However, when locomotor systems, such as wings in flying species, evolve to decrease such costs, it remains unclear whether functional changes across related species are achieved via the same morphological route or via alternate changes that have similar function. We conducted a comparative analysis of wing shape in relation to eye‐stalk elongation across 24 species of stalk‐eyed flies, using geometric morphometrics to determine how species with increased eye span, a sexually selected trait, have modified wing morphology as a compensatory mechanism. Using traditional and phylogenetically informed multivariate analyses of shape in combination with phenotypic trajectory analysis, we found a strong phylogenetic signal in wing shape. However, dimorphic species possessed shifted wing veins with the result of lengthening and narrowing wings compared to monomorphic species. Dimorphic species also had changes that seem unrelated to wing size, but instead may govern wing flexion. Nevertheless, the lack of a uniform, compensatory pattern suggests that stalk‐eyed flies used alternative modifications in wing structure to increase wing area and aspect ratio, thus taking divergent morphological routes to compensate for exaggerated eye stalks.     

Contrasting Patterns of Community Assembly in the Stratified Water Column of Great Salt Lake, Utah

Phylogenetic examinations of communities sampled along geochemical gradients provide a framework for inferring the relative importance of niche-based ecological interactions (competition, environmental filtering) and neutral-based evolutionary interactions in structuring biodiversity. Great Salt Lake (GSL) in Utah exhibits strong spatial gradients due to both seasonal variation in freshwater input into the watershed and restricted fluid flow within North America’s largest saline terminal lake ecosystem. Here, we examine the phylogenetic structure and composition of archaeal, bacterial, and eukaryal small subunit (SSU) rRNA genes sampled along a stratified water column (DWR3) in the south arm of GSL in order to infer the underlying mechanism of community assembly. Communities sampled from the DWR3 epilimnion were phylogenetically clustered (i.e., coexistence of close relatives due to environmental filtering) whereas those sampled from the DWR3 hypolimnion were phylogenetically overdispersed (i.e., coexistence of distant relatives due to competitive interactions), with minimal evidence for a role for neutral processes in structuring any assemblage. The shift from phylogenetically clustered to overdispersed assemblages was associated with an increase in salinity and a decrease in dissolved O₂ (DO) concentration. Likewise, the phylogenetic diversity and phylogenetic similarity of assemblages was strongly associated with salinity or DO gradients. Thus, salinity and/or DO appeared to influence the mechanism of community assembly as well as the phylogenetic diversity and composition of communities. It is proposed that the observed patterns in the phylogenetic composition and structure of DWR3 assemblages are attributable to the meromictic nature of GSL, which prevents significant mixing between the epilimnion and the hypolimnion. This leads to strong physicochemical gradients at the halocline, which are capable of supporting a greater diversity. However, concomitant shifts in nutrient availability (e.g., DO) at and below the halocline drive competitive interactions leading to hypolimnion assemblages with minimal niche overlap.     

Can habitat characteristics shape vertebral morphology in dolphins? An example of two phylogenetically related species from southern South America

Fast swimming pelagic cetacean species have osteological characteristics that promote a more stable spine in comparison to that of coastal species. The Peale's dolphin (Lagenorhynchus australis) and the hourglass dolphin (Lagenorhynchus cruciger) have a close phylogenetic relationship and are found in coastal and pelagic waters in the Southern Hemisphere, respectively. The aim of this work was to study the relationship between the vertebral column's morphology and its flexibility, across these species of contrasting habitats. Vertebral counts and multiple measurements of each vertebra were used to infer intervertebral flexibility. Bivariate plots and discriminant multivariate analyses were employed to compare each functional region along the vertebral column. Both species displayed a regionalization of the column into three stable regions and two flexible areas, which statistically differ in the proportion of the skeleton occupied in each species. While the Peale's dolphin has rounder vertebrae, associated with higher flexibility, the hourglass dolphin has disk‐shaped vertebrae and strongly inclined processes related to high stability. Although the species are closely related phylogenetically, vertebral morphology is influenced by a diverse set of ecological and behavioral factors, reflecting a high degree of vertebral plasticity within the genus.     

Deep phylogeny,net primary productivity,and global body size gradient in birds

Body size is evolutionarily constrained, but the influence of phylogenetic relationships on global body size (i.e. body mass) gradients is unexplored. We quantify and map the family‐level phylogenetic and non‐phylogenetic structure of the global gradient of birds, evaluating the extent to which it is influenced by phylogenetic inertia in contrast to heat conservation, resource availability, starvation resistance, niche conservatism, or interspecific competition. Phylogenetic eigenvector regression (PVR) partitioned the global bird body size gradient into phylogenetically autocorrelated (PA) and phylogenetically independent (PI) components. Simple, piecewise, and partial regressions were used to investigate associations between the PA and PI components of body size and environmental correlates, and to quantify independent and overlapping contributions of environment, phylogenetic autocorrelation, and species richness to the body size gradient. Two‐thirds of the geographic variation in bird body size can be explained by phylogenetic relationships at the family level. The global variation in body size, independent of phylogenetic relationships, is most strongly associated with net primary productivity, which is consistent with ‘starvation resistance’. However, the New and Old worlds have very different patterns. We found no independent association of species richness with body size. Despite major unresolved regional differences, deep phylogenetic relationships, heat conservation, and starvation resistance probably operate in concert in shaping the global bird body size gradient in different parts of the world. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Phylogenies and traits provide distinct insights about the historical and contemporary assembly of aquatic insect communities

The assumption that traits and phylogenies can be used as proxies of species niche has faced criticisms. Evidence suggested that phylogenic relatedness is a weak proxy of trait similarity. Moreover, different processes can select different traits, giving opposing signals in null model analyses. To circumvent these criticisms, we separated traits of stream insects based on the concept of α and β niches, which should give clues about assembling pressures expected to act independently of each other. We investigated the congruence between the phylogenetic structure and trait structure of communities using all available traits and all possible combinations of traits (4095 combinations). To account for hierarchical assembling processes, we analyzed patterns on two spatial scales with three pools of genera. Beta niche traits selected a priori – i.e., traits related to environmental variation (e.g., respiration type) – were consistently clustered on the smaller scale, suggesting environmental filtering, while α niche traits – i.e., traits related to resource use (e.g., trophic position) – did not display the expected overdispersion, suggesting a weak role of competition. Using all traits together provided random patterns and the analysis of all possible combinations of traits provided scenarios ranging from strong clustering to overdispersion. Communities were phylogenetically overdispersed, a pattern previously interpreted as phylogenetic limiting similarity. However, our results likely reflect the co‐occurrence of ancient clades due to the stability of stream habitats along the evolutionary scale. We advise ecologists to avoid using combinations of all available traits but rather carefully traits based on the objective under consideration. Both trait and phylogenetic approaches should be kept in the ecologist toolbox, but phylogenetic distances should not be used as proxies of traits differences. Although the phylogenetic structure revealed processes operating at the evolutionary scale, only specific traits explained local processes operating in our communities.     

Macroevolution and climate change influence phylogenetic community assembly of North American hoofed mammals

Animal richness, community composition, and phylogenetic community structure (PCS) vary across the modern landscape. Animal communities vary from phylogenetically clustered (i.e. higher relatedness amongst co‐occurring species than is expected by chance) to phylogenetically even (i.e. co‐occurring taxa are more distantly related than expected by chance), which is explained by abiotic or climatic filtering and competitive exclusion, respectively. Under this model, the contribution of historical origination and extinction events to modern animal PCS remains relatively unknown. Because origination and extinction determine the make‐up of the terrestrial community, the study of historical changes in animal PCS is tantamount to understanding formation of modern communities. In the present study, we test the effects of macroevolution and climate changes on ‘hoofed mammals’ (i.e. perissodactyl and artiodactyl) PCS from the late Cenozoic of North America because they experience large, phylogenetically dispersed extinctions of browsing species and phylogenetically dispersed originations of grazing species associated with the evolution of grassland ecosystems during the late Miocene. We show that the loss of numerically dominant nonhypsodont (putatively browsing and mixed feeding) clades and phylogenetically dispersed origination of less speciose clades following the mid Miocene climatic optimum led to an increase in phylogenetic evenness at the regional scale that is well explained by global climate changes. Phylogenetic evenness and a reduced richness during the late Cenozoic may have facilitated reduced niche overlap among co‐occurring hoofed mammal species as global climates cooled. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114 , 485–494.     

Competition and habitat filtering jointly explain phylogenetic structure of soil bacterial communities across elevational gradients

The importance of assembly processes in shaping biological communities is poorly understood, especially for microbes. Here, we report on the forces that structure soil bacterial communities along a 2000 m elevational gradient. We characterized the relative importance of habitat filtering and competition on phylogenetic structure and turnover in bacterial communities. Bacterial communities exhibited a phylogenetically clustered pattern and were more clustered with increasing elevation. Biotic factors (i.e., relative abundance of dominant bacterial lineages) appeared to be most important to the degree of clustering, evidencing the role of the competitive ability of entire clades in shaping the communities. Phylogenetic turnover showed the greatest correlation to elevation. After controlling the elevation, biotic factors showed greater correlation to phylogenetic turnover than all the habitat variables (i.e., climate, soil and vegetation). Structural equation modelling also identified that elevation and soil organic matter exerted indirect effects on phylogenetic diversity and turnover by determining the dominance of microbial competitors. Our results suggest that competition among bacterial taxa induced by soil carbon contributes to the phylogenetic pattern across elevational gradient in the Tibetan Plateau. This highlights the importance of considering not only abiotic filtering but also biotic interactions in soil bacterial communities across stressful elevational gradients.     

Phylogenetic structure of specialization: A new approach that integrates partner availability and phylogenetic diversity to quantify biotic specialization in ecological networks

Biotic specialization holds information about the assembly, evolution, and stability of biological communities. Partner availabilities can play an important role in enabling species interactions, where uneven partner availabilities can bias estimates of biotic specialization when using phylogenetic diversity indices. It is therefore important to account for partner availability when characterizing biotic specialization using phylogenies. We developed an index, phylogenetic structure of specialization (PSS), that avoids bias from uneven partner availabilities by uncoupling the null models for interaction frequency and phylogenetic distance. We incorporate the deviation between observed and random interaction frequencies as weights into the calculation of partner phylogenetic α‐diversity. To calculate the PSS index, we then compare observed partner phylogenetic α‐diversity to a null distribution generated by randomizing phylogenetic distances among the same number of partners. PSS quantifies the phylogenetic structure (i.e., clustered, overdispersed, or random) of the partners of a focal species. We show with simulations that the PSS index is not correlated with network properties, which allows comparisons across multiple systems. We also implemented PSS on empirical networks of host–parasite, avian seed‐dispersal, lichenized fungi–cyanobacteria, and hummingbird pollination interactions. Across these systems, a large proportion of taxa interact with phylogenetically random partners according to PSS, sometimes to a larger extent than detected with an existing method that does not account for partner availability. We also found that many taxa interact with phylogenetically clustered partners, while taxa with overdispersed partners were rare. We argue that species with phylogenetically overdispersed partners have often been misinterpreted as generalists when they should be considered specialists. Our results highlight the important role of randomness in shaping interaction networks, even in highly intimate symbioses, and provide a much‐needed quantitative framework to assess the role that evolutionary history and symbiotic specialization play in shaping patterns of biodiversity. PSS is available as an R package at https://github.com/cjpardodelahoz/pss.     

Global variation in the relationship between avian phylogenetic diversity and functional distance is driven by environmental context and constraints

Aim

If evolutionary distance is akin to evolutionary chance, then it follows that species assemblages that are distantly related will also be more disparate in terms of their traits, features and the niches they occupy. Yet, studies have found that the total phylogenetic distance of an assemblage, known as phylogenetic diversity, is an unreliable surrogate for functional diversity. We investigate global variation in the relationship between Faith's phylogenetic diversity (PD) and mean pairwise functional distance (MPFD) across latitude and the influence of migratory species on both these aspects of diversity.

Location

Global.

Time period

Present day.

Major taxa studied

Birds.

Methods

We measure PD and MPFD for over 9000 species of bird across more than 17,000 globally distributed assemblages. We obtain standardised effect sizes for both indices by simulating assemblage composition under an ecologically informed null model. We employ path analysis to characterize variation in the relationship between PD's and MPFD across latitude, elevation and with proportion of migratory species.

Results

Globally, assemblages that were phylogenetically diverse tended to be less functionally dispersed than expected; however, this relationship showed considerable variation across latitude decreasing with distance from the equator. The proportion of migratory species in an assemblage was found to be an important predictor of functional diversity, with migrant rich assemblages generally showing less functional diversity than expected. We identify the Andes and Hengduan Mountains as regions of exceptional bird functional diversity.

Main conclusions

The relationship between phylogenetic diversity and function diversity is context specific, varying across environmental gradients such as latitude, and influenced by ecological phenomena such as migration. Thus, care should be taken using phylogenetic diversity as a proxy for functional diversity, particularly in clades with sparse functional data. Instead, we recommend that studies consider how phylogenetic diversity's surrogacy for functional diversity may be impacted by environmental context and evaluate empirical observations against biogeographically constrained and ecologically informed null models.     

Taxonomic and functional aspects of the patterning of enamel thickness distribution in extant large-bodied hominoids

One of the few uncontested viewpoints in studies of enamel thickness is that the molars of the African apes, Pan and Gorilla, possess "thin" enamel, while Pongo and modern humans possess varying degrees of "thick" enamel, even when interspecific differences in overall body or tooth size are taken into account. Such studies focus primarily on estimates of the total volume of enamel relative to tooth size (i.e., "relative" enamel thickness), as this is thought to bear directly on questions concerning dietary proclivities and phylogenetic relationships. Only recently have studies shifted focus to examining differences in the distribution of enamel across the tooth crown, i.e., the patterning of enamel thickness, as this may contribute to more refined models of tooth function and dietary adaptations in extant hominoids. Additionally, this feature has been suggested to be a reliable indicator of taxonomic affinity in early hominins, though no study has specifically addressed whether species-specific patterns exist among known phena. The aims of this paper were to test more explicitly whether enamel thickness patterning provides valuable taxonomic, functional, and/or phylogenetic information for maxillary molars of large-bodied extant hominoids. A series of seven linear enamel thickness measurements was recorded in the plane of the mesial cusps in cross sections of a total of 62 maxillary molars of P. troglodytes, G. gorilla, P. pygmaeus, and H. sapiens to estimate the patterning of enamel thickness distribution. Results from a discriminant function analysis reveal that, overall, this trait reclassifies extant hominoid maxillary molars with 90% accuracy: 100% of extant Homo, 75. 0% of Pongo, 83.3% of Pan, and 66.7% of Gorilla are reclassified correctly, indicating that this feature possesses a strong taxonomic signal. Furthermore, differences in the structure of the enamel cap are evident among hominoids: modern humans differ from Pongo in possessing proportionally thicker enamel in areas of the crown associated with shearing activity; Pan molars are better designed than those of Gorilla for generating a greater component of crushing/grinding loads. Thus, African ape molars are structurally dissimilar, even though they are both considered to belong to a morphologically homogeneous "thin-enameled" group. Simple developmental mechanisms can be invoked to explain the sometimes subtle differences in the achievement of adult morphology. For instance, human and orangutan molar cusps possess a similar degree of enamel thickness, but the possibility exists that despite similarities in morphology, each species follows a different sequence of secretory activity of enamel to achieve the final, albeit similar, degree of enamel thickness. Such a finding would suggest that the shared possession of "thick" or "thin" enamel among species may be phylogenetically uninformative, as it would not represent a developmental synapomorphy.     

Precision and accuracy in quantifying herbivory

1. Tissue removal by herbivores (i.e. herbivory) is a dominant interaction in most communities which has important impacts on natural and managed ecosystems. Despite the importance of herbivory, we lack a quantitative comparison of the efficacy of the most commonly used methods used to quantify herbivore damage. 2. We examined the factors that affect the precision and accuracy of visual and digital methods commonly used to quantify damage to leaves. 3. We created 224 digital leaves from four plant species. In a fully factorial design we manipulated leaf morphology and species, the location of damage (marginal or internal), estimation method (exact percentage or 25% bins), observer experience and expectancy bias (i.e., bias due to an expected result). Using 583 adult observers, we estimated the precision and accuracy of individuals' ability to visually estimate known levels of damage. In a third smaller experiment, we performed similar analyses using a digital scanner. 4. Across the first two experiments, individuals estimated damage with high precision (R² = 0.75 and 0.80) and accuracy (slope_{actual vs estimated} = 0.88 and 0.86). However, the precision and accuracy of estimates were influenced by plant species, the location of damage, and estimation method. Inexperienced individuals also overestimated low levels of damage, and this bias decreased with experience. Digital methods were precise (R² = 0.98) whereas accuracy was statistically indistinguishable from visual methods (slope = 0.91). 5. Visual estimates of damage provide the fastest and most cost‐effective method for quantifying herbivory, and our results show they can be precise and accurate. We use our results to provide specific recommendations for future research.     

Phylogenetic signal in tooth wear dietary niche proxies

In the absence of independent observational data, ecologists and paleoecologists use proxies for the Eltonian niches of species (i.e., the resource or dietary axes of the niche). Some dietary proxies exploit the fact that mammalian teeth experience wear during mastication, due to both tooth‐on‐tooth and food‐on‐tooth interactions. The distribution and types of wear detectible at micro‐ and macroscales are highly correlated with the resource preferences of individuals and, in turn, species. Because methods that quantify the distribution of tooth wear (i.e., analytical tooth wear methods) do so by direct observation of facets and marks on the teeth of individual animals, dietary inferences derived from them are thought to be independent of the clade to which individuals belong. However, an assumption of clade or phylogenetic independence when making species‐level dietary inferences may be misleading if phylogenetic niche conservatism is widespread among mammals. Herein, we test for phylogenetic signal in data from numerous analytical tooth wear studies, incorporating macrowear (i.e., mesowear) and microwear (i.e., low‐magnification microwear and dental microwear texture analysis). Using two measures of phylogenetic signal, heritability (H²) and Pagel's λ, we find that analytical tooth wear data are not independent of phylogeny and failing to account for such nonindependence leads to overestimation of discriminability among species with different dietary preferences. We suggest that morphological traits inherited from ancestral clades (e.g., tooth shape) influence the ways in which the teeth wear during mastication and constrain the foods individuals of a species can effectively exploit. We do not suggest that tooth wear is simply phylogeny in disguise; the tooth wear of individuals and species likely varies within some range that is set by morphological constraints. We therefore recommend the use of phylogenetic comparative methods in studies of mammalian tooth wear, whenever possible.     

Comparison between Colony Morphology and Molecular Phylogeny in the Caribbean Scleractinian Coral Genus Madracis

A major challenge in coral biology is to find the most adequate and phylogenetically informative characters that allow for distinction of closely related coral species. Therefore, data on corallite morphology and genetic data are often combined to increase phylogenetic resolution. In this study, we address the question to which degree genetic data and quantitative information on overall coral colony morphologies identify similar groupings within closely related morphospecies of the Caribbean coral genus Madracis. Such comparison of phylogenies based on colony morphology and genetic data will also provide insight into the degree to which genotype and phenotype overlap. We have measured morphological features of three closely related Caribbean coral species of the genus Madracis (M. formosa, M. decactis and M. carmabi). Morphological differences were then compared with phylogenies of the same species based on two nuclear DNA markers, i.e. ATPSα and SRP54. Our analysis showed that phylogenetic trees based on (macroscopical) morphological properties and phylogenetic trees based on DNA markers ATPSα and SRP54 are partially similar indicating that morphological characteristics at the colony level provide another axis, in addition to commonly used features such as corallite morphology and ecological information, to delineate genetically different coral species. We discuss this new method that allows systematic quantitative comparison between morphological characteristics of entire colonies and genetic data.