Dean C Adams

• PhD
• Distinguished Professor at Iowa State University

In the arid landscapes of the Arabian Peninsula, high levels of cryptic diversity among reptiles, and especially in geckos, have recently been revealed. Mountain ranges within the peninsula were shown to contain the highest richness of reptile endemicity, serving as refugia to species less adapted to the hyper-arid conditions of the lowlands. With...

Evolutionary biologists characterize macroevolutionary trends of phenotypic change across the tree of life using phylogenetic comparative methods. However, within‐species variation can complicate such investigations. For this reason, procedures for incorporating nonstructured (random) intraspecific variation have been developed. Likewise, evolution...

Among geckos, an ideal group to investigate the roles of population dynamics and ecological adaptation in species diversification are semaphore geckos of the genus Pristurus. Numerous ecologically diverse species can be found across Afro-Arabia. On the one hand, strong environmental gradients promoting ecological speciation are present; on the othe...

Due to the hierarchical structure of the tree of life, closely related species often resemble each other more than distantly related species; a pattern termed phylogenetic signal. Numerous univariate statistics have been proposed as measures of phylogenetic signal for single phenotypic traits, but the study of phylogenetic signal for multivariate d...

The Montseny brook newt (Calotriton arnoldi), a glacial relict endemic to a small, isolated massif in northeast Spain, is considered the only Critically Endangered urodele in Europe. Its restricted range is divided by a deep valley that acts as an impassable barrier to dispersal, separating two isolated metapopulations (Western and Eastern) that co...

The evolution of miniaturization can result in dramatic alterations of morphology, physiology and behavior; however the effects of miniaturization on sexual dimorphism remain largely unknown. Here we investigate how miniaturization influences patterns of sexual size dimorphism (SSD) in geckos. Measuring 1,875 individuals from 131 species, we characte...

Measurement error is present in all quantitative studies, and ensuring proper biological inference requires that the effects of measurement error are fully scrutinized, understood, and to the extent possible, minimized. For morphometric data, measurement error is often evaluated from descriptive statistics that find ratios of subject or within-subj...

The Montseny brook newt (Calotriton arnoldi), considered the most endangered amphibian in Europe, is a relict salamandrid species endemic to a small massif located in northeastern Spain. Although conservation efforts should always be guided by genomic studies, those are yet scarce among urodeles, hampered by the extreme sizes of their genomes. Here...

Convergent evolution is widely regarded as a signature of adaptation. However, testing the adaptive consequences of convergent phenotypes is challenging, making it difficult to exclude non-adaptive explanations for convergence. Here, we combined feather reflectance spectra and phenotypic trajectory analyses with visual and thermoregulatory modellin...

Figure SM2.1. Linear measurements used to assess static allometry and RR in shape in green lizards. *Measurements used to calculate head size.

Figure SM4.1. Allometric relationships between each of studied morphological traits and body size (SVL) in green lizards, without talking allometric differences between the sexes into account, used to visualize general tendencies of slope variation across species (but see main results for the supported statistical models). A. trunk length; B. head...

Supplementary Material 5, Reyes-Puig et al., 2023. Rensch’s rule: linking intraspecific to evolutionary allometry

Supplementary Material 6, Reyes-Puig et al., 2023. Rensch’s rule: linking intraspecific to evolutionary allometry

Supplementary Material 3, Reyes-Puig et al., 2023. Rensch’s rule: linking intraspecific to evolutionary allometry

Sexual dimorphism describes phenotypic differences between the sexes; the most prominent of which is sexual size dimorphism (SSD). Rensch's Rule (RR) is an allometric trend in which SSD increases in male-larger taxa and decreases in female-larger ones. Covariation between a trait and overall size within and across species can both be affected by se...

Species living in distinct habitats often experience unique ecological selective pressures, which can drive phenotypic divergence. However, how ecophenotypic patterns are affected by allometric trends and trait integration levels is less well understood. Here we evaluate the role of allometry in shaping body size and body form diversity in Pristuru...

Supplementary Material

Measurement error is present in all quantitative studies, and ensuring proper biological inference requires that the effects of measurement error are fully scrutinized, understood, and to the extent possible, minimized. For morphometric data, measurement error is often evaluated from descriptive statistics that find ratios of subject or within-subj...

Sexual dimorphism (SD) is a common feature of animals, and selection for sexually dimorphic traits may affect both functional morphological traits and organismal performance. Trait evolution through natural selection can also vary across environments. However, whether the evolution of organismal performance is distinct between the sexes is rarely t...

Understanding how and why phenotypic traits covary is a major interest in evolutionary biology. Biologists have long sought to characterize the extent of morphological integration in organisms, but comparing levels of integration for a set of traits across taxa has been hampered by the lack of a reliable summary measure and testing procedure. Here...

Eyes are remarkable systems to investigate the complex interaction between ecological drivers and phenotypic outcomes. Some animals, such as scallops, have many eyes for visual perception, but to date, the evolution of multiple‐eye systems remains obscure. For instance, it is unclear whether eye number changes over a lifetime or varies among specie...

Simulation‐based and permutation‐based inferential methods are commonplace in phylogenetic comparative methods, especially as evolutionary data have become more complex and parametric methods more limited for their analysis. Both approaches simulate many random outcomes from a null model to empirically generate sampling distributions of statistics....

Macroevolutionary studies frequently characterize the phylogenetic signal in phenotypes; however, analytical tools for comparing the strength of that signal across traits remain largely underdeveloped. We developed a non‐parametric, permutation test for the log‐likelihood of an evolutionary model, plus a standardized statistic, , from this test, wh...

Sexual dimorphism is a common feature in animals, yet the degree of sexual dimorphism is not constant across taxa. Sometimes the magnitude of sexual dimorphism varies systematically with body size, resulting in evolutionary allometry of sexual dimorphism. While such patterns are commonly investigated for traits such as overall size, allometric vari...

Geometric morphometric (GM) tools are essential for meaningfully quantifying and understanding patterns of variation in complex traits like shape. In this field, the breadth of answerable questions has grown dramatically in recent years through the development of new analyses and increased computational efficiency. In this note, we describe the way...

Identifying the historical processes that drive microhabitat transitions across deep time is of great interest to evolutionary biologists. Morphological variation can often reveal such mechanisms, but in clades with high microhabitat diversity and no concomitant morphological specialization, the factors influencing animal transitions across microha...

Lesion severity scales have been developed for a number of wildlife diseases causing external pathology. Perhaps the best known and most widely used scoring system has been developed for finch mycoplasmosis in which observers measure conjunctival pathology along a four-point scale of increasing severity. We developed novel techniques to characteriz...

1. It has become common in evolutionary biology to characterize phenotypes multivariately. However, visualizing macroevolutionary trends in multivariate datasets requires appropriate ordination methods. 2. In this paper we describe phylogenetically aligned component analysis (PACA): a new ordination approach that aligns phenotypic data with phylo...

Researchers using geometric morphometric methods can be confronted with a need to combine separate landmark configurations from the same research subjects as a more holistic description of organismal morphology. Combining configurations might be valid if single configurations represent separate anatomical structures that can change position with re...

Organismal performance is often key in understanding macroevolutionary patterns but characterizing performance across many species is challenging, as the disparate geographic locations of taxa often prohibit in vivo measures. In theory, however, inferences on the evolution of performance could be investigated using anatomical approximations of perf...

Complementing biology lecture courses with laboratory sections is nearly universal at undergraduate institutions, yet many topics in biology do not easily lend themselves to experiment-based laboratory activities. Topics such as comparative anatomy, evolution and systematics are often taught as passive, observation-based laboratories. In this exper...

Allometric trends in the degree of sexual dimorphism with body size have long fascinated evolutionary biologists. Many male‐biased clades display more prominent sexual dimorphism in larger taxa (Rensch's rule), with most examples documenting this pattern for body size dimorphism. While sexual dimorphism in traits other than body size is equally fun...

Evolutionary biologists have long been interested in the macroevolutionary consequences of various selection pressures, yet physiological responses to selection across deep time are not well understood. In this paper, we investigate how a physiologically‐relevant morphological trait, surface area to volume ratio (SA:V) of lungless salamanders, has...

The study of modularity is paramount for understanding trends of phenotypic evolution, and for determining the extent to which covariation patterns are conserved across taxa and levels of biological organization. However, biologists currently lack quantitative methods for statistically comparing the strength of modular signal across datasets, and a...

Evolutionary biology is multivariate, and advances in phylogenetic comparative methods for multivariate phenotypes have surged to accommodate this fact. Evolutionary trends in multivariate phenotypes are derived from distances and directions between species in a multivariate phenotype space. For these patterns to be interpretable, phenotypes should...

Evolutionary theory predicts that selection in distinct microhabitats generates correlations between morphological and ecological traits, and may increase both phenotypic and taxonomic diversity. However, some microhabitats exert unique selective pressures that act as a restraining force on macroevolutionary patterns of diversification. In this stu...

Timing of nesting affects fitness of oviparous animals living in seasonal environments, and females may cue on environmental factors for their nesting behavior, but these relationships are understudied in tropical turtles. Here, the timing and synchrony of egg-laying relative to environmental factors were examined in the South American freshwater t...

Grass leaf shape is a strong indicator of their habitat with linear leaves predominating in open areas and ovate leaves distinguishing forest‐associated grasses. This pattern among extant species suggests that ancestral shifts between forest and open habitats may have coincided with changes in leaf shape or size. We tested relationships between hab...

Residual randomization in permutation procedures (RRPP) is an appropriate means of generating empirical sampling distributions for ANOVA statistics and linear model coefficients, using ordinary or generalized least‐squares estimation. This is an especially useful approach for high‐dimensional (multivariate) data. Here, we present an r package that...

Phylogenetic regression is frequently utilized in macroevolutionary studies, and its statistical properties have been thoroughly investigated. By contrast, phylogenetic ANOVA has received relatively less attention, and the conditions leading to incorrect statistical and biological inferences when comparing multivariate phenotypes among groups remai...

In oviparous vertebrates lacking parental care, resource allocation during reproduction is a major maternal effect that may enhance female fitness. In general, resource allocation strategies are expected to follow optimality models to solve the energy trade-offs between egg size and number. Such models predict that natural selection should optimize...

Evaluating trait correlations across species within a lineage via phylogenetic regression is fundamental to comparative evolutionary biology, but when traits of interest are derived from two sets of lineages that co-evolve with one another, methods for evaluating such patterns in a dual-phylogenetic context remain underdeveloped. Here we extend mul...

Background: Rates of morphological evolution vary across different taxonomic groups, and this has been proposed as one of the main drivers for the great diversity of organisms on Earth. Of the extrinsic factors pertaining to this variation, ecological hypotheses feature prominently in observed differences in phenotypic evolutionary rates across li...

An important question in evolutionary biology is how often, and to what extent, do similar ecologies elicit distantly related taxa to evolve towards the same phenotype? In some scenarios, the repeated evolution of particular phenotypes may be expected, for instance when species are exposed to common selective forces that result from strong function...

Recent years have seen increased interest in phylogenetic comparative analyses of multivariate datasets, but to date the varied proposed approaches have not been extensively examined. Here we review the mathematical properties required of any multivariate method, and specifically evaluate existing multivariate phylogenetic comparative methods in th...

The natural history of organisms can have major effects on the tempo and mode of evolution, but few examples show how unique natural histories affect rates of evolution at macroevolutionary scales. European plethodontid salamanders (Plethodontidae: Hydromantes) display a particular natural history relative to other members of the family. Hydromante...

poster

p>Many recent reviews and meta-analyses of N₂O emissions do not include data from Mediterranean studies. In this paper we present a meta-analysis of the N₂O emissions from Mediterranean cropping systems, and propose a more robust and reliable regional emission factor (EF) for N₂O, distinguishing the effects of water...

Many recent reviews and meta-analyses of N2O emissions do not include data from Mediterranean studies. In this paper we present a meta-analysis of the N2O emissions from Mediterranean cropping systems, and propose a more robust and reliable regional emission factor (EF) for N2O, distinguishing the effects of water management, crop type, and fertili...

Evolutionary morphologists frequently wish to understand the extent to which organisms are integrated, and whether the strength of morphological integration among subsets of phenotypic variables differ among taxa or other groups. However, comparisons of the strength of integration across datasets are difficult, in part because the summary measures...

Predators influence the evolution of colour pattern in prey species, yet how these selective forces might differ among predators is rarely considered. In particular, prey colour patterns that indicate unpalatability to some predator species may not carry the same signal for other predators. We test several hypotheses of selection on patterning betw...

Directional evolution is one of the most compelling evolutionary patterns observed in macroevolution. Yet, despite its importance, detecting such trends in multivariate data remains a challenge. In this study, we evaluate multivariate evolution of shell shape in 93 bivalved scallop species, combining geometric morphometrics and phylogenetic compara...

Modularity describes the case where patterns of trait covariation are unevenly dispersed across traits. Specifically, trait correlations are high and concentrated within subsets of variables (modules), but the correlations between traits across modules are relatively weaker. For morphometric data sets, hypotheses of modularity are commonly evaluate...

The comparison of mathematical models that represent alternative hypotheses about the tempo and mode of evolutionary change is a common approach for assessing the evolutionary processes underlying phenotypic diversification. However, because model parameters are estimated simultaneously, they are inextricably linked, such that changes in tempo, the...

The interplay between evolutionary rates and modularity influences the evolution of organismal body plans by both promoting and constraining the magnitude and direction of trait response to ecological conditions. However, few studies have examined whether the best-fit hypothesis of modularity is the same as the shape subset with the greatest differ...

The resemblance between palatable mimics and unpalatable models in Batesian mimicry systems is tempered by many factors, including the toxicity of the model species. Model toxicity is thought to influence both the occurrence of mimicry and the evolution of mimetic phenotypes, such that mimicry is most likely to persist when models are particularly...

How organisms respond to environmental change is a long-standing question in evolutionary biology. Species invading novel habitats provide an opportunity to examine contemporary evolution in action, and decipher the pace of evolutionary change over short time scales. Here we characterized phenotypic evolution in the Italian plethodontid salamander,...

Background Misconceptions about biological evolution specifically and the nature of science in general are pervasive in our society and culture. The view that biological evolution explains life’s origin(s) and that hypotheses become theories, which then become laws are just two examples of commonly held misconceptions. These misconceptions are rein...

How fish functional morphology shapes species co-existence and assemblage diversity patterns is a fundamental issue in ecological research. In fishes, much is known about the ecomorphological relationships of feeding morphology in coral reef fishes and in freshwater taxa inhabiting distinct environments. However, little is known about the patterns...

Conspicuousness, or having high contrast relative to the surrounding background, is a common feature of unpalatable species. Several hypotheses have been proposed to explain the occurrence of conspicuousness, and while most involve the role of conspicuousness as a direct signal of unpalatability to potential predators, one hypothesis suggests that...

Evaluating statistical trends in high-dimensional phenotypes poses challenges for comparative biologists, because the high-dimensionality of the trait data relative to the number of species can prohibit parametric tests from being computed. Recently, two comparative methods were proposed to circumvent this difficulty. One obtains phylogenetic indep...

Understanding how phenotypic diversity evolves is a major interest of evolutionary biology. Habitat use is an important factor in the evolution of phenotypic diversity of many animal species. Interestingly, male and female phenotypes have been frequently shown to respond differently to environmental variation. At the macroevolutionary level, this d...

The analysis of phenotypic change is important for several evolutionary biology disciplines, including phenotypic plasticity, evolutionary developmental biology, morphological evolution, physiological evolution, evolutionary ecology and behavioral evolution. It is common for researchers in these disciplines to work with multivariate phenotypic data...

Studies of evolutionary correlations commonly utilize phylogenetic regression (i.e., independent contrasts and phylogenetic generalized least squares) to assess trait covariation in a phylogenetic context. However, while this approach is appropriate for evaluating trends in one or a few traits, it is incapable of assessing patterns in highly-multiv...

Phylogenetic signal is the tendency for closely related species to display similar trait values due to their common ancestry. Several methods have been developed for quantifying phylogenetic signal in univariate traits and for sets of traits treated simultaneously, and the statistical properties of these approaches have been extensively studied. Ho...

Morphological integration describes the degree to which sets of organismal traits covary with one another. Morphological covariation may be evaluated at various levels of biological organization, but when characterizing such patterns across species at the macroevolutionary level, phylogeny must be taken into account. We outline an analytical proced...

Ecological selection forces for weedy and domesticated traits have influenced the evolution of seed shape in Setaria resulting in similarity in seed shape that reflects similarity in ecological function rather than reflecting phylogenetic relatedness. Seeds from two diploid subspecies of Setaria viridis, consisting of one weedy subspecies and two r...

Reduction in body size is a major response to climate change, yet evidence in globally imperiled amphibians is lacking. Shifts in average population body size could indicate either plasticity in the growth response to changing climates through changes in allocation and energetics, or through selection for decreased size where energy is limiting. We...

Hidden Diversity Why are there so many species in the tropics? Niche partitioning by highly specialized plant species seems to be the main generator of high diversity. Condon et al. (p. 1240 ; see the Perspective by Godfray ) show that niche partitioning can also be generated by interactions between plant resources and parasites, resulting in hyper...

Repeated patterns of phenotypic divergence between environments across disparate taxa provide strong evidence for the generation of adaptive phenotypes. Flow velocity is an important selective force in aquatic habitats; however, among vertebrates, the study of its effects on morphology has been limited almost exclusively to fully-aquatic bony fishe...

Many questions in evolutionary biology require the quantification and comparison of rates of phenotypic evolution. Recently, phylogenetic comparative methods have been developed for comparing evolutionary rates on a phylogeny for single, univariate traits (σ(2)), and evolutionary rate matrices (R) for sets of traits treated simultaneously. However,...

In Batesian mimicry a palatable mimic deceives predators by resembling an unpalatable model. The evolution of Batesian mimicry relies on the visual capabilities of the potential predators, as prey detection provides the selective force driving evolutionary change. We compared the visual capabilities of several potential predators to test prediction...

Background/Question/Methods: Climate change models project widespread range contractions for Appalachian salamanders within the next decade, with greatest effects predicted for species in the southern Appalachians. Climate change can impact amphibians through shifts in species distributions, leaner body condition, and reduced growth. These impacts...

DNA methylation plays an important role in the epigenetic control of developmental and behavioral plasticity, with connections to the generation of striking phenotypic differences between castes (larger, reproductive queens and smaller, non-reproductive workers) in honeybees and ants. Here, we provide the first comparative investigation of caste- a...

Background Wing size and shape have important aerodynamic implications on flight performance. We explored how wing size was related to wing shape in territorial males of 37 taxa of the damselfly family Calopterygidae. Wing coloration was also included in the analyses because it is sexually and naturally selected and has been shown to be related to...

Flight has conferred an extraordinary advantage to some groups of animals. Wing shape is directly related to flight performance and evolves in response to multiple selective pressures. In some species, wings have ornaments such as pigmented patches that are sexually selected. Since organisms with pigmented wings need to display the ornament while f...

Sexual size dimorphism (SSD) is widespread in nature and may result from selection operating differentially on males and females. Rensch’s rule, the increase of SSD with body size in male-biased-SSD species (or decrease in female-biased-SSD species), is documented in invertebrates and vertebrates. In turtles, evidence for Rensch’s rule is inconclus...

Hummingbirds are known for their distinctive patterns of sexual dimorphism, with many species exhibiting sex-related differences in various ecologically-relevant traits, including sex-specific differences in bill shape. It is generally assumed that such patterns are consistent across all hummingbird lineages, yet many taxa remain understudied. In t...

Many ecological and evolutionary studies seek to explain patterns of shape variation and its covariation with other variables. Geometric morphometrics is often used for this purpose, where a set of shape variables are obtained from landmark coordinates following a P rocrustes superimposition. We introduce geomorph: a software package for performing...

Geographically structured variation in morphol-ogy is a common phenomenon in animals with environmental factors covarying with both latitude and biogeographic bar-riers having profound impacts on body size and shape. The Pacific blue-eye (Pseudomugil signifer) is a freshwater fish that lives along Australia's east coast and occurs on either side of...

Evolutionary and ecological theory generates testable predictions concerning the effects of species interactions on ecological, behavioral, and morphological traits. Throughout Ohio, two closely related and ecologically similar salamander species, Plethodon cinereus and P. electromorphus, occur in similar habitats and in many localities are found i...

Evolutionary and ecological theory generates testable predictions concerning the effects of species interactions on ecological, behavioral, and morphological traits. Throughout Ohio, two closely related and ecologically similar salamander species, Plethodon cinereus and P. electromorphus, occur in similar habitats and in many localities are found i...

Twenty years ago, Rohlf and Marcus proclaimed that a "revolution in morphometrics" was underway, where classic analyses based on sets of linear distances were being supplanted by geometric approaches making use of the coordinates of anatomical landmarks. Since that time the field of geometric morphometrics has matured into a rich and cohesive disci...

Research using shape data from geometric morphometric (GM) methods in ecology and evolutionary biology is typically comparative, analyzing shapes and shape change over different points along ecological or evolutionary gradients. Whereas standard multivariate statistics procedures are fine for "static" variation testing for location differences of g...

Coloration is a trait frequently cited as important to ecological, and thus evolutionary, processes in amphibians. To fully understand the impact of coloration, a consistent method of color measurement is required, which is often achieved by collecting color information in a captive, laboratory setting. However, results from the lab can only be gen...

In recent years, likelihood-based approaches have been used with increasing frequency to evaluate macroevolutionary hypotheses of phenotypic evolution under distinct evolutionary processes in a phylogenetic context (e.g., Brownian motion, Ornstein-Uhlenbeck, etc.), and to compare one or more evolutionary rates for the same phenotypic trait along a...

Understanding the relationship between form and function is central to our comprehension of how phenotypic diversity evolves. Traits involved in multiple activities, such as social interactions and ecological resource use, are under the influence of different evolutionary forces potentially acting in opposite directions. Such systems provide the op...

The tempo and mode of species diversification and phenotypic evolution vary widely across the tree of life, yet the relationship between these processes is poorly known. Previous tests of the relationship between rates of phenotypic evolution and rates of species diversification have assumed that species richness increases continuously through time...