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The braincase anatomy of the Pennsylvanian diadectomorph Limnoscelis dynatis is described in detail, based upon high-resolution X-ray microcomputed tomography. Both supraoccipitals and most of the prootics and opisthotics are preserved. The known portions of the left prootic, opisthotic, and supraoccipital enclose complete sections of the endosseous labyrinth, including the anterior, posterior, and lateral semicircular canals, the vestibule, the cochlear recess, and the canal for the endolymphatic duct. The fossa subarcuata is visible anteromedial to the anterior semicircular canal. The presumed endolymphatic fossae occur in the dorsal wall of the posteromedial portion of the supraoccipital. Both the fossa subarcuata and the fossa endolymphatica lie in the cerebellar portion of the cranial cavity. In order to investigate the phylogenetic position of L. dynatis we used a recently published data matrix, including characters of the braincase, and subjected it to maximum parsimony analyses under a variety of character weighting schemes and to a Bayesian analysis. Limnoscelis dynatis emerges as sister taxon to L. paludis, and both species form the sister group to remaining diadectomorphs. Synapsids and diadectomorphs are resolved as sister clades in ∼90% of all the most parsimonious trees from the unweighted analysis, in the single trees from both the reweighted and the implied weights analyses, as well in the Bayesian tree.

Although the graptolites lacked biomineralised tissue, their skeletons are abundantly preserved in deeper-water mudstones. Decay experiments and observations on the closely related living hemichordate Rhabdopleura demonstrate that the periderm and stolon are highly resistant to decay, remaining intact for mouths, whereas the zooids are unrecognizable within days. Curie-point-gas-chromatography (Py-GC) and Curie-point-gas-chromatography-mass spectrometry (Pt-GC-MS) of the periderm of Rhabdopleura confirms that proteinaceous organic matter is a major constituent. Ultrastructurally preserved graptolite periderm, on the other hand, is a highly altered kerogen-like substance rich in aliphatic biomacromolecules. The composition of the preserved graptolite periderm reflects diagenetic replacement by components probably mainly derived from algal cell walls. -from Authors

Metazoans evolved in the sea and quickly invaded benthic niches. It was from these niches that other large ecosystems were colonized through the later Precambrian and the Phanerozoic. Entering these new environments, the colonists encountered new sets of macroevolutionary controls. Narratives of each colonization are important for historical ecology, while comparison of different events can throw light on these underlying controls. Recent narrative work on the evolution of plankton has suggested that this series of events was unique in respect of its duration and method. Animals have been migrating into the plankton since the Proterozoic, and all the main planktic groups have a benthic origin. Migration was usually by single species acting independently of their native community. A comparison with the other major Phanerozoic colonization, that of the land, highlights these unusual features. Colonization of the land began in the Ordovician and seems to have occurred sporadically. Several of the major groups of terrestrial animals originated on land. The invasion of land is usually related to the evolution of land plants and is perhaps best regarded as migration at the level of the community. The major differences between the two colonizations may be attributable to the dominant control of the environment over plankton versus that of biotic interaction over land animals.

Two methods are used to examine feeding strategies in graptoloids; the first profiles different sets of zooids on the colony, the second treats the colony as a whole. Both of these techniques have advantages. The choice between them brings into question our concepts of the degree of coloniality shown by graptoloids. Using a whole colony model, graptoloids can be shown to have sampled the water with variable efficiency, as defined in this paper. Planar forms were relatively inefficient, generally sampling less than 10 of the available water. Inclined forms frequently approached 75 efficiency. Biserial forms and straight monograptids routinely exceeded 100, sampling each unit of water more than once. Rotation of the rhabdosome during movement increased the efficiency of horizontal and inclined forms. It reduced the efficiency of scandent biserials and straight monograptids. These were both advantageous effects. Astogenetic changes in colony size and form would have had a profound effect on feeding efficiency. -Author

Zooplankton show a unique pattern of evolution with successive waves of invasion into the water column from the benthos. It has been found that 18 of 21 planktonic groups whose ancestry can be traced originated in the benthos. New recruits have survived and radiated if preadapted to remain in the plankton, but no major clades have evolved there. The innovative steps into the planktic realm do not coincide with major global events such as mass extinctions. This unusual pattern of evolution, a one-way track into a particular environment, demonstrates the profound effect of the ecosystem on large-scale patterns and processes of evolution. -from Authors

Individuals' reproductive success is often strongly associated with their age, with typical patterns of early-life reproductive improvement and late-life senescence. These age-related patterns are due to the inherent trade-offs between life-history traits competing for a limited amount of resources available to the organisms. In males, such trade-offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their life span. Due to the age dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitudinal data in a lekking species with strong sexual selection – the black grouse Lyrurus tetrix – we quantified the effects of age, life span and age of first lek attendance (AFL) on male annual mating success (AMS) to separate the effects of within-individual improvement and senescence on AMS from selective (dis)appearance of certain phenotypes. Then, we used male AMS to quantify univariate and multivariate sexual selection gradients on male morphological and behavioural traits with and without accounting for age and age-related effects of other traits. Male AMS increased with age, and there was no significant reproductive senescence. Most males never copulated, and of the ones that did, the majority had only one successful year. Life span was unrelated to AMS, but early AFL tended to lead to higher AMS at ages 1–3. AMS was related to most morphological and behavioural traits when male age was ignored. Accounting for age and age-specific trait effects (i.e. the interaction between a trait and age) reduced the magnitude of the selection gradients and revealed that behavioural traits are under consistent sexual selection, while sexual selection on morphological traits is stronger in old males. Therefore, sexual selection in black grouse operates primarily on male behaviour and morph

In the majority of insects, sperm fertilize the egg via a narrow canal through the outer chorion called the micropyle. Despite having this one primary function, there is considerable unexplained variation in the location, arrangement and number of micropyles within and between species. Here, we examined the relationship between micropyle number and female mating pattern through a comparative analysis across Lepidoptera. Three functional hypotheses could explain profound micropylar variation: (i) increasing micropyle number reduces the risk of infertility through sperm limitation in species that mate infrequently; (ii) decreasing micropyle number reduces the risk of pathological polyspermy in species that mate more frequently; and (iii) increasing micropyle number allows females to exert greater control over fertilization within the context of post-copulatory sexual selection, which will be more intense in promiscuous species. Micropyle number was positively related to the degree of female promiscuity as measured by spermatophore count, regardless of phylogenetic signal, supporting the hypothesis that micropyle number is shaped by post-copulatory sexual selection. We discuss this finding in the context of cryptic female choice, sperm limitation and physiological polyspermy.

The origin of amniotes was a key event in vertebrate evolution, enabling tetrapods to break their ties with water and invade terrestrial environments. Two pivotal clades of early tetrapods, the diadectomorphs and the seymouriamorphs, have played an unsurpassed role in debates about the ancestry of amniotes for over a century, but their skeletal morphology has provided conflicting evidence for their affinities. Using high-resolution X-ray microcomputed tomography, we reveal the three-dimensional architecture of the well preserved endosseous labyrinth of the inner ear in representative species belonging to both groups. Data from the inner ear are coded in a new cladistic matrix of stem and primitive crown amniotes. Both maximum parsimony and Bayesian inference analyses retrieve seymouriamorphs as derived non-crown amniotes and diadectomorphs as sister group to synapsids. If confirmed, this sister group relationship invites re-examination of character polarity near the roots of the crown amniote radiation. Major changes in the endosseous labyrinth and adjacent braincase regions are mapped across the transition from non-amniote to amniote tetrapods, and include: a ventral shift of the cochlear recess relative to the vestibule and the semicircular canals; cochlear recess (primitively housed exclusively within the opisthotic) accommodated within both the prootic and the opisthotic; development of a distinct fossa subarcuata. The inner ear of seymouriamorphs foreshadows conditions of more derived groups, whereas that of diadectomorphs shows a mosaic of plesiomorphic and apomorphic traits, some of which are unambiguously amniote-like, including a distinct and pyramid-like cochlear recess.

Individual differences in contributions to cooperation can be strikingly consistent over time giving rise to alternative cooperative phenotypes within animal societies. Following the social niche specialization hypothesis, these consistent differences may be driven by social conflict over reproductive opportunities if individuals specializing as ‘breeders’ and ‘nonbreeders’ experience a beneficial reduction in social conflict and differential costs associated with cooperating. This hypothesis gives three testable predictions: (1) consistent individual differences in cooperative behaviour will be accompanied by consistent individual differences in reproductive behaviour, (2) individuals contributing heavily to reproduction will contribute relatively little to cooperative behaviours within the same breeding attempt and vice versa, and (3) individuals that consistently contribute heavily to reproduction over their lifetime will also consistently contribute less to cooperative behaviours and vice versa. We tested these predictions with a 15-year investigation into the lifetime patterns of mate guarding and two forms of cooperative offspring care (‘babysitting’ and ‘escorting’) in a wild population of banded mongooses. We found significant repeatability of individual contributions to both cooperative behaviours, as well as significant repeatability of individual levels of mate guarding. However, we found no evidence of negative covariance between contributions to cooperative and reproductive behaviours either within breeding attempts or across lifetimes. This suggests that the observed consistent individual differences in both cooperative behaviour and reproduction are not associated; there is no evidence of a trade-off between reproduction and cooperation. However, we found a significant positive covariance between babysitting and escorting when estimated both within breeding attempts and across lifetimes, which suggests that some group members are generally more cooper

Male ornaments function as honest cues of male quality in many species and are subject to intra‐ and intersexual selection. These ornaments are generally studied during peak expression, however their size outside the breeding season may determine ultimate ornament size and costliness, and as such reproductive success. We investigated whether male black grouse Lyrurus tetrix eye comb size was related to age, condition and measures of male dominance before and during the breeding season. Total combined eye comb size began to increase ~70 days before the start of the breeding season. Adult males (aged ≥ 2 years old) had consistently larger eye combs than younger males (1 year old) both before and during the breeding season. Heavier and more dominant adult males (attending the lek more frequently and successfully reproducing) had larger eye combs. For younger males, those that were heavier had larger eye combs. Additionally, males that spent more time on the lek showed increased eye comb size as the breeding season approached. Overall we find that ornament size is positively related to dominance and condition before and during the breeding season. Since dominance is accrued through year‐round interactions in many species, the ability to maintain larger signals over prolonged periods, including outside of the breeding season, is likely to be beneficial for adults. For younger males, it is likely that they cannot sustain or are constrained from producing larger eye combs over long periods of time. They therefore prioritise growth of their ornaments later, and according to the amount of time they spend on the lek.

Recent studies have revealed a variety of left–right asymmetries among vertebrates and invertebrates.In many species, left- and right-lateralized individuals coexist, but in unequal numbers (‘population-level’ lateralization). It has been argued that brain lateralization increases individual efficiency (e.g.avoiding unnecessary duplication of neural circuitry and reducing interference between functions),thus counteracting the ecological disadvantages of lateral biases in behaviour (making individualbehaviour more predictable to other organisms). However, individual efficiency does not require adefinite proportion of left- and right-lateralized individuals. Thus, such arguments do not explainpopulation-level lateralization. We have previously shown that, in the context of prey–predatorinteractions, population-level lateralization can arise as an evolutionarily stable strategy whenindividually asymmetrical organisms must coordinate their behaviour with that of other asymmetricalorganisms. Here, we extend our model showing that populations consisting of left- and right-lateralizedindividuals in unequal numbers can be evolutionarily stable, based solely on strategic factors arisingfrom the balance between antagonistic (competitive) and synergistic (cooperative) interactions.

Adaptation is the fundamental driver of functional and biomechanical evolution. Accordingly, the states of biomechanical traits (absolute or relative trait values) have long been used as proxies of adaptations in response to direct selection. However, ignoring evolutionary history, in particular ancestry, passage of time and the rate of evolution, can be misleading. Here, we apply a recently developed phylogenetic statistical approach using significant rate shifts to detect instances of exceptional rates of adaptive changes in bite force, in a large group of terrestrial vertebrates, the amniotes. Our results show that bite force in amniotes evolved through multiple bursts of exceptional rates of adaptive changes, whereby whole groups – including Darwin’s finches, maniraptoran dinosaurs (group of non-avian dinosaurs including birds), anthropoids and hominins (the group of species including modern humans) – experienced significant rate increases compared to the background rate. However, in most parts of the amniote tree of life we find no exceptional rate increases, indicating that coevolution with body size was primarily responsible for the patterns observed in bite force. Our approach represents a template for future studies in functional morphology and biomechanics, where exceptional rates of adaptative changes can be quantified and potentially linked to specific ecological factors underpinning major evolutionary radiations.

Baron-Cohen's extreme male brain theory proposes that autism results from elevated prenatal testosterone levels. In the present study, we assessed possible correlated effects of androgen exposure on adult morphology and, in particular, the development of facial features associated with masculinity. We created composite images capturing statistical regularities in facial appearance associated with high and low Autism-Spectrum Quotient (AQ) scores. In three experiments, we assessed correlations between perceived facial masculinity and AQ scores. In Experiment 1, observers selected the high-AQ males as more masculine. We replicated this result in Experiment 2, using different photographs, composite-image methods, and observers. There was no association of masculinity and AQ scores for female faces in either study. In Experiment 3, we created high- and low-AQ male composites from the five AQ subscales. High-AQ images were rated more masculine on each of the subscales. We discuss these findings with respect to the organizational-activational hypothesis of testosterone activity during development.

Depression is a common mental health disorder, with 12 of the UK population diagnosed at any one time. We assessed whether there are cues to depressive symptoms within the static, non-expressive face, and if other socially relevant impressions might be made by these cues. Composite "average" face images were created from students scoring high and low on self-report measures of depressive symptoms, capturing potential correlations between facial appearance and symptoms of depression. These were then used in a warping procedure, creating two versions of individual faces, one warped towards the high symptom composite, and the other towards the low. In Experiment 1, we first found observers were able to identify images representing high and low symptom occurrence at levels significantly greater than chance. Secondly, we collected observer impressions of the two versions of each face. The faces reflecting high levels of depressive symptoms were picked as less socially desirable over a broad range of personality trait estimates compared to low symptom images. In Experiment 2, we replicated the key finding that the static face contains cues to levels of depression symptoms, using composites created from a new database of student photos and depression inventory scores.

Evidence of left–right asymmetries in invertebrates has begun to emerge, suggesting that lateralization of the nervous system may be a feature of simpler brains as well as more complex ones. A variety of studies have revealed sensory and motor asymmetries in behaviour, as well as asymmetries in the nervous system, in invertebrates. Asymmetries in behaviour are apparent in olfaction (antennal asymmetries) and in vision (preferential use of the left or right visual hemifield during activities such as foraging or escape from predators) in animals as different as bees, fruitflies, cockroaches, octopuses, locusts, ants, spiders, crabs, snails, water bugs and cuttlefish. Asymmetries of the nervous system include lateralized position of specific brain structures (e.g., in fruitflies and snails) and of specific neurons (e.g., in nematodes). As in vertebrates, lateralization can occur both at the individual and at the population-level in invertebrates. Theoretical models have been developed supporting the hypothesis that the alignment of the direction of behavioural and brain asymmetries at the population-level could have arisen as a result of social selective pressures, when individually asymmetrical organisms had to coordinate with each other. The evidence reviewed suggests that lateralization at the population-level may be more likely to occur in social species among invertebrates, as well as vertebrates.

In most studies about dioecious plants, the role of arbuscular mycorrhizae (AM) and the potential sex-specific differences between the plant hosts have been overlooked. Because plant sexes frequently differ in drought tolerance and AM fungal colonization provides higher resistance to drought, we investigated whether the relation of mycorrhizal fungi with either male or female Antennaria dioica plants differs using a factorial experiment. We hypothesized that because AM usually increase growth rate and male plants usually grow larger than females, males should gain more benefit from the mycorrhizal symbiosis in terms of mineral nutrition and water supply. Because of higher demands of carbohydrates (C) in males, we expected males to allocate less C resources to the mycorrhizal fungus so that the associated fungi should benefit less of the association with males. In contrast to our initial hypothesis, the male plants, although faster growing under drought, did not gain more symbiosis-mediated benefits than did the females, and both sexes seemed to provide resources equally to their fungal symbiont. Therefore, we conclude that the two plant sexual morphs provide equal amounts of C to their fungal root symbionts and that they can gain specific benefits from the symbiosis, which, however, depend on soil water availability.

Why sex evolved and persists is a problem for evolutionary biology, because sex disrupts favourable gene combinations and requires an expenditure of time and energy. Further, in organisms with unequal-sized gametes, the female transmits her genes at only half the rate of an asexual equivalent (the twofold cost of sex). Many modern theories that provide an explanation for the advantage of sex incorporate an idea originally proposed by Weismann more than 100 years ago: sex allows natural selection to proceed more effectively because it increases genetic variation. Here we test this hypothesis, which still lacks robust empirical support, with the use of experiments on yeast populations. Capitalizing on recent advances in the molecular biology of recombination in yeast, we produced by genetic manipulation strains that differed only in their capacity for sexual reproduction. We show that, as predicted by the theory, sex increases the rate of adaptation to a new harsh environment but has no measurable effect on fitness in a new benign environment where there is little selection.

Individual resource specialisation is common in natural populations associated with competition and ecological opportunity (see Aroujo et al., 2011), and well known for the killer whale (where social groups specialise) and other delphinid cetaceans (see Hoelzel, 2002). Prey choice affects a predator’s temporal and spatial pattern of habitat use. For the killer whale, social groups (pods) learn where prey resources are seasonally abundant, and the techniques required to exploit different resources efficiently. Some fish prey, especially anadromous species such as salmon, may provide predictable seasonally rich concentrations, whereas marine mammal prey may be more patchily distributed and show a different pattern of temporal abundance (and accessibility). However, these resources are found within the same waters, though the timing and technique for capture may differ. Foote and Morin (2015) suggest that the co-occurrence of populations in the same ocean doesn't necessarily imply that they differentiated in sympatry, which is clearly true. However, as Moura et al. (2015) and others (for example, Hoelzel et al., 1998, 2007) have discussed, it is the life history and behaviour of killer whales that suggest the potential for differentiation in sympatry. Although the proximity of resources brings killer whale pods into sympatry, the differential pattern of spatial and temporal habitat use, as well as fidelity to pods that forage by similar learned methods, could serve to isolate resource specialist communities reproductively.

Global extinction and geological events have previously been linked with galactic events such as spiral arm crossings and galactic plane oscillation. The expectation that these are repeating predictable events has led to studies of periodicity in a wide set of biological, geological and climatic phenomena. Using data on carbon isotope excursions, large igneous provinces and impact craters, we identify three time zones of high geological activity which relate to the timings of the passage of the Solar System through the spiral arms. These zones are shown to include a significantly large proportion of high extinction periods. The mass extinction events at the ends of the Ordovician, Permian and Cretaceous occur in the first zone, which contains the predicted midpoints of the spiral arms. The start of the Cambrian, end of the Devonian and end of the Triassic occur in the second zone. The pattern of extinction timing in relation to spiral arm structure is supported by the positions of the superchrons and the predicted speed of the spiral arms. The passage times through an arm are simple multiples of published results on impact and fossil record periodicity and galactic plane half-periods. The total estimated passage time through four arms is 703.8 Myr. The repetition of extinction events at the same points in different spiral arm crossings suggests a common underlying galactic cause of mass extinctions, mediated through galactic effects on geological, solar and extra-solar processes. The two largest impact craters (Sudbury and Vredefort), predicted to have occurred during the early part of the first zone, extend the possible pattern to more than 2000 million years ago. © 2008 Cambridge University Press.

Studies were undertaken on the floristic composition and stand structure of four 1 hectare plots in the lowland forests of Kurupukari, Guyana. A total of 3897 trees, covering 153 species and 31 plant families were recorded at greater than 5 cm diameter at breast height (dbh). The number of species per hectare ranged from 61 to 84 (>5.0 cm dbh) and 50–71 (>10.0 cm dbh). The total number of trees per hectare varied two-fold between study plots, with 45–50% of the trees within the 5–10 cm size-class. Mean total basal area varied from 32.39–34.63 m2 per 100 m2. The four most dominant plant families represented 43.8% of the total number of trees, while representing only 11.2% of the species. No one plant family dominated in more than one of the four study plots, and all four plots held at least one plant family with more than 20% of the total number of trees. Although 14 tree species were common to all four plots, only 26%–35% of the species were represented by a single tree. Between three and seven species represented 50% of the trees within all size-classes, with species dominance occurring within the highest density plot. These tropical forest types of central Guyana may represent some of the lowest diversity forests in the neotropics, whereby the total number of tree species is relatively limited, typically with six dominant canopy species, but the relative abundance of these species is highly variable between the forest types. Mechanisms influencing the competitive interactions associated with species dominance are discussed in relation to the importance of mycorrhizae and the persistence of species dominance.

For many highly mobile species, the marine environment presents few obvious barriers to gene flow. Even so, there is considerable diversity within and among species, referred to by some as the ‘marine speciation paradox’. The recent and diverse radiation of delphinid cetaceans (dolphins) represents a good example of this. Delphinids are capable of extensive dispersion and yet many show fine-scale genetic differentiation among populations. Proposed mechanisms include the division and isolation of populations based on habitat dependence and resource specializations, and habitat release or changing dispersal corridors during glacial cycles. Here we use a phylogenomic approach to investigate the origin of differentiated sympatric populations of killer whales (Orcinus orca). Killer whales show strong specialization on prey choice in populations of stable matrifocal social groups (ecotypes), associated with genetic and phenotypic differentiation. Our data suggest evolution in sympatry among populations of resource specialists.

Understanding the evolution of diversity and the resulting systematics in marine systems is confounded by the lack of clear boundaries in oceanic habitats, especially for highly mobile species like marine mammals. Dolphin populations and sibling species often showdifferentiation between coastal and offshore habitats, similar to the pelagic/littoral or benthic differentiation seen for some species of fish. Here we test the hypothesis that lineages within the polytypic genus Tursiops track past changes in the environment reflecting ecological drivers of evolution facilitated by habitat release. We used a known recent time point for calibration (the opening of the Bosphorus) and whole mitochondrial genome (mitogenome) sequences for high phylogenetic resolution. The pattern of lineage formation suggested an origin in Australasia and several early divisions involving forms currently inhabiting coastal habitats. Radiation in pelagic environments was relatively recent, and was likely followed by a return to coastal habitat in some regions. The timing of some nodes defining different ecotypes within the genus clustered near the two most recent interglacial transitions. A signal for an increase in diversification was also seen for dates after the last glacial maximum. Together these data suggest the tracking of habitat preference during geographic expansions, followed by transition points reflecting habitat shifts, which were likely associated with periods of environmental change.

Selfish genes demonstrate transmission bias and invade sexual populations despite conferring no benefit to their hosts. While the molecular genetics and evolutionary dynamics of selfish genes are reasonably well characterized, their effects on hosts are not. Homing endonuclease genes (HEGs) are one well-studied family of selfish genes that are assumed to be benign. However, we show that carrying HEGs is costly for Saccharomyces cerevisiae, demonstrating that these genetic elements are not necessarily benign but maybe parasitic. We estimate a selective load of approximately 1-2 in 'natural' niches. The second aspect we examine is the ability of HEGs to affect hosts' sexual behaviour. As all selfish genes critically rely on sex for spread, then any selfish gene correlated with increased host sexuality will enjoy a transmission advantage. While classic parasites are known to manipulate host behaviour, we are not aware of any evidence showing a selfish gene is capable of affecting host promiscuity. The data presented here show a selfish element may increase the propensity of its eukaryote host to undergo sex and along with increased rates of non-Mendelian inheritance, this may counterbalance mitotic selective load and promote spread. Demonstration that selfish genes are correlated with increased promiscuity in eukaryotes connects with ideas suggesting that selfish genes promoted the evolution of sex initially. © 2013 The Authors Published by the Royal Society. All rights reserved.

News & Comment: paper review: Balkovsky, E. and Shraiman, B.I. (2002) Olfactory search at high Reynolds numbers. Proc. Natl. Acad. Sci. U. S. A. 10.1073/pnas.192393499

The rise and diversification of the dinosaurs in the Late Triassic, from 230 to 200 million years ago, is a classic example of an evolutionary radiation with supposed competitive replacement. A comparison of evolutionary rates and morphological disparity of basal dinosaurs and their chief "competitors," the crurotarsan archosaurs, shows that dinosaurs exhibited lower disparity and an indistinguishable rate of character evolution. The radiation of Triassic archosaurs as a whole is characterized by declining evolutionary rates and increasing disparity, suggesting a decoupling of character evolution from body plan variety. The results strongly suggest that historical contingency, rather than prolonged competition or general "superiority," was the primary factor in the rise of dinosaurs.

Reptiles are one of the most ecologically and evolutionarily remarkable groups of living organisms, having successfully colonized most of the planet, including the oceans and some of the harshest and more environmentally unstable ecosystems on earth. Here, based on a complete dataset of all the world's diversity of living reptiles, we analyse lineage taxonomic richness both within and among clades, at different levels of the phylogenetic hierarchy. We also analyse the historical tendencies in the descriptions of new reptile species from Linnaeus to March 2012. Although (non-avian) reptiles are the second most species-rich group of amniotes after birds, most of their diversity (96.3) is concentrated in squamates (59 lizards, 35 snakes, and 2 amphisbaenians). In strong contrast, turtles (3.4), crocodilians (0.3), and tuataras (0.01) are far less diverse. In terms of species discoveries, most turtles and crocodilians were described early, while descriptions of lizards, snakes and amphisbaenians are multimodal with respect to time. Lizard descriptions, in particular, have reached unprecedented levels during the last decade. Finally, despite such remarkably asymmetric distributions of reptile taxonomic diversity among groups, we found that the distributions of lineage richness are consistently right-skewed, with most clades (monophyletic families and genera) containing few lineages (monophyletic genera and species, respectively), while only a few have radiated greatly (notably the families Colubridae and Scincidae, and the lizard genera Anolis and Liolaemus). Therefore, such consistency in the frequency distribution of richness among clades and among phylogenetic levels suggests that the nature of reptile biodiversity is fundamentally fractal (i.e., it is scale invariant). We then compared current reptile diversity with the global reptile diversity and taxonomy known in 1980. Despite substantial differences in the taxonomies (relative to 2012), the patterns of lineage ri

Large-scale patterns of current species geographic range-size variation reflect historical dynamics of dispersal and provide insights into future consequences under changing environments. Evidence suggests that climate warming exerts major damage on high latitude and elevation organisms, where changes are more severe and available space to disperse tracking historical niches is more limited. Species with longer generations (slower adaptive responses), such as vertebrates, and with restricted distributions (lower genetic diversity, higher inbreeding) in these environments are expected to be particularly threatened by warming crises. However, a well-known macroecological generalization (Rapoport's rule) predicts that species range-sizes increase with increasing latitude-elevation, thus counterbalancing the impact of climate change. Here, I investigate geographic range-size variation across an extreme environmental gradient and as a function of body size, in the prominent Liolaemus lizard adaptive radiation. Conventional and phylogenetic analyses revealed that latitudinal (but not elevational) ranges significantly decrease with increasing latitude-elevation, while body size was unrelated to range-size. Evolutionarily, these results are insightful as they suggest a link between spatial environmental gradients and range-size evolution. However, ecologically, these results suggest that Liolaemus might be increasingly threatened if, as predicted by theory, ranges retract and contract continuously under persisting climate warming, potentially increasing extinction risks at high latitudes and elevations. © 2011 Daniel Pincheira-Donoso.

Bergmann's rule predicts larger body sizes in species living in higher latitudes and altitudes. This rule appears to be valid for endotherms, but its relevance to ectotherm vertebrates has largely been debated. In squamate reptiles (lizards and snakes), only one study, based on Liolaemus species of the boulengeri clade, has provided phylogenetic evidence in favour of Bergmann's clines. We reassessed this model in the same lizard clade, using a more representative measure of species body size and including a larger number of taxa in the sample. We found no evidence to support Bergmann's rule in this lineage. However, these non-significant results appear to be explained only by the inclusion of further species rather than by a different estimation of body size. Analyses conducted on the 16 species included in the previous study always revealed significant relationships between body size and latitude-altitude, whereas, the enlarged sample always rejected the pattern predicted by Bergmann's rule. © 2007 The Authors.

Background. The impact of environmental gradients on the evolution of life history traits is a central issue in macroecology and evolutionary biology. A number of hypotheses have been formulated to explain factors shaping patterns of variation in animal mass. One such example is Bergmann's rule, which predicts that body size will be positively correlated with latitude and elevation, and hence, with decreasing environmental temperatures. A generally accepted explanation for this phenotypic response is that as body mass increases, body surface area gets proportionally smaller, which contributes to reduced rates of heat-loss. Phylogenetic and non-phylogenetic evidence reveals that endotherms follow Bergmann's rule. In contrast, while previous non-phylogenetic studies supported this prediction in up to 75 of ectotherms, recent phylogenetic comparative analyses suggest that its validity for these organisms is controversial and less understood. Moreover, little attention has been paid to why some ectotherms conform to this rule, while others do not. Here, we investigate Bergmann's rule in the six main clades forming the Liolaemus genus, one of the largest and most environmentally diverse genera of terrestrial vertebrates. A recent study conducted on some species belonging to four of these six clades concluded that Liolaemus species follow Bergmann's rule, representing the only known phylogenetic support for this model in lizards. However, a later reassessment of this evidence, performed on one of the four analysed clades, produced contrasting conclusions. Results. Our results fail to support Bergmann's rule in Liolaemus lizards. Non-phylogenetic and phylogenetic analyses showed that none of the studied clades experience increasing body size with increasing latitude and elevation. Conclusion. Most physiological and behavioural processes in ectotherms depend directly upon their body temperature. In cold environments, adaptations to gain heat rapidly are under strong positiv

Adaptive radiation theory predicts that phenotypic traits involved in ecological performance evolve in different directions in populations subjected to divergent natural selection, resulting in the evolution of ecological diversity. This idea has largely been supported through comparative studies exploring relationships between ecological preferences and quantitative traits among different species. However, intersexual perspectives are often ignored. Indeed, although it is well established that intersexual competition and sex-specific parental and reproductive roles may often subject sex-linked phenotypes to antagonistic selection effects, most ecomorphological research has explored adaptive evolution on a single sex, or on means obtained from both sexes together. The few studies taking sexual differences into account reveal the occurrence of sex-specific ecomorphs in some clades of lizards, and conclude that the independent contribution of the sexes to the morphological diversity produced by adaptive radiation can be substantial. Here, we investigate whether microhabitat use results in the evolution of sex-specific ecomorphs across 44 Liolaemus lizard species. We found that microhabitat structure does not predict variation in body size and shape in either of the sexes. Yet, we found that males and females tend to occupy significantly different positions in multivariate morphological spaces, indicating that treating males and females as ecologically and phenotypically equivalent units may lead to incomplete or mistaken estimations of the diversity produced by adaptive evolution. © The Ecological Society of Japan 2009.

Large brains relative to body size represent an evolutionarily costly adaptation as they are metabolically expensive and demand substantial amounts of time to reach structural and functional maturity thereby exacerbating offspring mortality while delaying reproductive age. In spite of its cost and adaptive impact, no genomic features linked to brain evolution have been found. By conducting a genome-wide analysis in all 37 fully sequenced mammalian genomes, we show that encephalization is significantly correlated with overall protein amino acid composition. This correlation is not a by-product of changes in nucleotide content, lifespan, body size, absolute brain size or genome size; is independent of phylogenetic effects; and is not restricted to brain expressed genes. This is the first report of a relationship between this fundamental and complex trait and changes in protein AA usage, possibly reflecting the high selective demands imposed by the process of encephalization across mammalian lineages.

Aim Temperature influences most components of animal ecology and life history – but what kind of temperature? Physiologists usually examine the influence of body temperatures, while biogeographers and macroecologists tend to focus on environmental temperatures. We aim to examine the relationship between these two measures, to determine the factors that affect lizard body temperatures and to test the effect of both temperature measures on lizard life history. Location World-wide. Methods We used a large (861 species) global dataset of lizard body temperatures, and the mean annual temperatures across their geographic ranges to examine the relationships between body and mean annual temperatures.We then examined factors influencing body temperatures, and tested for the influence of both on ecological and life-history traits while accounting for the influence of shared ancestry. Results Body temperatures and mean annual temperatures are uncorrelated. However, accounting for activity time (nocturnal species have low body temperatures), use of space (fossorial and semi-aquatic species are ‘colder’), insularity (mainland species are ‘hotter’) and phylogeny, the two temperatures are positively correlated. High body temperatures are only associated with larger hatchlings and increased rates of biomass production. Annual temperatures are positively correlated with clutch frequency and annual longevity, and negatively correlated with clutch size, age at first reproduction and longevity. Main conclusions Lizards with low body temperatures do not seem to have ‘slower’ life-history attributes than species with high body temperatures. The longer seasons prevalent in warm regions, and physiological processes that operate while lizards are inactive (but warm enough), make environmental temperatures better predictors of lizard life-history variation than body temperatures. This surprisingly greater effect of environmental temperatures on lizard life histories hints that global warming

Geographical variation in environmental temperatures is expected to impose clinal phenotypic selection that results in the expression of large-scale gradients of body mass variation within animal clades. Body size is predicted to increase with increasing latitude and elevation, and hence, with decreasing temperature, a pattern broadly known as Bergmann's rule. However, empirical observations are highly conflicting. Whilst most studies support this prediction in endotherms (birds and mammals), analyses conducted on ectotherms often fail to report this pattern. Does it reduce the validity of this macroecological rule? Since the original formulation of Bergmann's rule only involved endothermic organisms, I argue that the controversy is not a consequence of its predictive power, but a result of the later inclusion of ectotherms as part of the prediction. Here, I propose that the common conception of Bergmann's rule maintained for half a century is changed back to its original definition restricted to endotherms. This temperature-size relationship might therefore consolidate as a well-established macroecological rule if its original formulation is respected. Finally, I develop these claims on my initial suggestion that Bergmann's rule should be recognized as the evolutionary outcome of a general process with no phylogenetic scale distinction of species or populations, being equally applicable amongst and within species. © 2010 Springer-Verlag.

Fecundity is a primary component of fitness. Theory predicts that the evolution of fecundity through increased brood size results from fecundity selection favouring larger female size to accommodate more offspring and to store more energy. This is expected to generate asymmetric selection on body size between the sexes, ultimately driving evolution of female-biased sexual size dimorphism. Additionally, it has been predicted that the intensity of fecundity selection increases when the opportunities for reproduction are reduced by the limiting thermal effects of increasing latitude-elevation (i.e. decreasing environmental temperatures) on the length of the reproductive season. This later factor would be particularly strong among ectotherms, where reproduction is heavily temperature-dependent. However, this integrative perspective on reproductive evolution by fecundity selection has rarely been investigated. Here, we employ a comparative approach to investigate these predictions in Liolaemus, a prominent lizard radiation. As expected, Liolaemus reproductive output (i. e. offspring number per reproductive episode) increases predictably with increasing female size. However, contrary to predictions, we found that increased fecundity does not translate into female-biased SSD, and that combined latitude-elevation does not impose a detectable effect on fecundity. Finally, our allometric analyses reveal that SSD scales with body size, which supports the occurrence of Rensch's rule in these lizards. We discuss the evolutionary implications of our results, and the assumptions of the investigated hypotheses. © 2011 Springer Science+Business Media, LLC.

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Climatic gradients impose clinal selection on animal ecological and physiological performance, often promoting geographic body size clines. Bergmann's rule predicts that body size increases with decreasing environmental temperatures given the need to retain body-heat through adjustments of body-mass-to-surface-area ratio. This prediction generally holds for endotherms, but remains controversial for ectotherms. An alternative interpretation, the 'resource rule', suggests that food abundance, primary productivity and precipitation (which, unlike temperature, do not necessarily correlate with geography), drive body size clines. We investigate geographic variation in body size within 65 species of lizards and snakes (squamates) based on an intercontinental dataset (6,500+ specimens belonging to 56 Israeli species, and multiple populations of nine Liolaemus species from Argentina and Chile). Bergmann's rule is only rarely supported by our data (in four species, 6%), whereas six species (9%) follow its converse (hence, it is unsupported in 94% of cases). Similarly, size increases with resource abundance in only 12 species (18%). Therefore, although neither of the rules is supported, factors suggested by the resource rule are better predictors of body size than temperature. Surprisingly, we show that some measures of the extent of a species' climatic envelope do not affect the likelihood of it showing a size-climate relationship. We conclude that negative size-temperature associations are an exception rather than a generality among squamates.

Male katydids (Orthoptera: Tettigoniidae) produce mating calls by rubbing the wings together, using specialized structures in their forewings (stridulatory file, scraper and mirror). A large proportion of species (ca. 66%) reported in the literature produces ultrasonic signals as principal output. Relationships among body size, generator structures and the acoustic parameters carrier frequency (fc) and pulse duration (pd), were studied in 58 tropical species that use pure-tone signals. A comparative analysis, based on the only available katydid phylogeny, shows how changes in sound generator form are related to changes in fc and pd. Anatomical changes of the sound generator that might have been selected via fc and pd are mirror size, file length and number of file teeth. Selection for structures of the stridulatory apparatus that enhance wing mechanics via file-teeth and scraper morphology was crucial in the evolution of ultrasonic signals in the family Tettigoniidae.

Recent fossil finds inChina andArgentina have provided startling new insights into the reproductive biology and embryology of pterosaurs, Mesozoic flying reptiles. Nineteen embryos distributed among four species representing three distinct clades have been described and all are assumed to be at, or near, term. We show here how the application of four contrasting quantitative approaches allows a more precise identification of the developmental status of embryos revealing, for the first time to our knowledge, the presence of middle and late developmental stages as well as individuals that were at term. We also identify a predicted relationship between egg size and shape and the developmental stage of embryos contained within. Small elongate eggs contain embryos at an earlier stage of development than larger rounder eggs which contain more fully developed embryos. Changes in egg shape and size probably reflect the uptake of water, consistent with a pliable shell reported for several pterosaurs. Early ossification of the vertebral column, limb girdles and principal limb bones involved some heterochronic shifts in appearance times, most notably of manus digit IV, and facilitated full development of the flight apparatus prior to hatching. This is consistent with a super-precocial flight ability and, while not excluding the possibility of parental care in pterosaurs, suggests that it was not an absolute requirement.

La specializzazione funzionale dell’emisfero destro e sinistro nel cervello è una caratteristica condivisa da moltissime specie animali, dall’uomo all’ape.

The mechanisms underlying rapid macro evolution are controversial.One largely untested hypothesis that could inform this debate is that evolutionary reversals might release variation in vestigial traits, which then facilitate subsequent diversification. We evaluated this idea by testing key predictions about vestigial traits arising from sexual trait reversal in wild field crickets. In Hawaiian Teleogryllus oceanicus, the recent genetic loss of sound producing and amplifying structures on male wings eliminates their acoustic signals.Silence protects these ‘flatwing’ males from an acoustically orienting parasitoid and appears to have evolved independently more than once.Here we report that flatwing males show enhanced variation in vestigial resonator morphology under varied genetic backgrounds. Using laser Doppler vibrometry, we found that these vestigial sound-producing wing features resonate at highly variable acoustic frequencies well outside the normal range for this species. These results satisfy two important criteria for a mechanism driving rapid evolutionary diversification: sexual signal loss was accompanied by a release of vestigial morphological variants, and these could facilitate the rapid evolution of novel signal values. Widespread secondary trait losses have been inferred from fossil and phylogenetic evidence across numerous taxa, and our results suggest that such reversals could play a role in shaping historical patterns of diversification.

The products of microbial metabolism form an integral part of human industry and have been shaped by evolutionary processes, accidentally and deliberately, for thousands of years. In the production of wine, a great many flavour and aroma compounds are produced by yeast species and are the targets of research for commercial breeding programs. Here we demonstrate how co-evolution with multiple species can generate novel interactions through serial co-culture in grape juice. We find that after 65 generations, co-evolved strains and strains evolved independently show significantly different growth aspects and exhibit significantly different metabolite profiles. We show significant impact of co-evolution of Candida glabrata and Pichia kudriavzevii on the production of metabolites that affect the flavour and aroma of experimental wines. While co-evolved strains do exhibit novel interactions that affect the reproductive success of interacting species, we found no evidence of cross-feeding behaviour. Our findings yield promising avenues for developing commercial yeast strains by using co-evolution to diversify the metabolic output of target species without relying on genetic modification or breeding technologies. Such approaches open up exciting new possibilities for harnessing microbial co-evolution in areas of agriculture and food related research generally.

Male ornaments function as honest cues of male quality in many species and are subject to intra- and intersexual selection. These ornaments are generally studied during peak expression, however their size outside the breeding season may determine ultimate ornament size and costliness, and as such reproductive success. We investigated whether male black grouse Lyrurus tetrix eye comb size was related to age, condition and measures of male dominance before and during the breeding season. Total combined eye comb size began to increase ~70 d before the start of the breeding season. Adult males (aged ≥ 2 yr old) had consistently larger eye combs than younger males (1 yr old) both before and during the breeding season. Heavier and more dominant adult males (attending the lek more frequently and successfully reproducing) had larger eye combs. For younger males, those that were heavier had larger eye combs. Additionally, males that spent more time on the lek showed increased eye comb size as the breeding season approached. Overall we find that ornament size is positively related to dominance and condition before and during the breeding season. Since dominance is accrued through year-round interactions in many species, the ability to maintain larger signals over prolonged periods, including outside of the breeding season, is likely to be beneficial for adults. For younger males, it is likely that they cannot sustain or are constrained from producing larger eye combs over long periods of time. They therefore prioritise growth of their ornaments later, and according to the amount of time they spend on the lek.

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Determining accurate phylogenetic relationships of species within the genus Tursiops and closely related Delphininae species, has remain a challenging task for evolutionary cetologists. Previous studies have not agreed on the monophyletic status of this genus, and although cross-lineage reticulations has been suggested as a main driver of phylogenetic uncertainty, no formal test of this has been carried out. In this study, we use a double digest RADseq protocol, to carry out a high resolution nuclear phylogenetic study of the Delphininae, with particular emphasis on species/ecotypes of the genus Tursiops. We also carried out cross-lineage reticulation analyses, and tested for several sources of bias in determining phylogenies from whole-genome data. Our results suggest likely monophily for the genus Tursiops, with the recently described T. australis grouping within the T. aduncus lineage. We also show the presence of extensive cross-lineage gene flow between pelagic and European coastal ecotypes of T. truncatus, as well as in the early stages of diversification between spotted (Stenella frontalis; Stenella attenuate), common (Delphinus delphis), spinner (Stenella longirostris), Fraser (Lagenodelphis hosei) and striped dolphins (Stenella coeruleoalba). Our study provides a significant step in our understanding of the group’s evolutionary history, and demonstrates that patterns of cross-lineage gene flow might have been more extensive and complex that previously thought. Furthermore, we make recommendation regarding potential taxonomic classification within the genus Tursiops, and propose a sub-species status for previously well described ecotypes.

Aim: Community assembly is traditionally assumed to result from speciation and colonization mediated by available niche space. This paradigm is expanded by the theory that niche space can also be saturated by intersexual adaptive divergence (ecological sexual dimorphism) when interspecific competition is relaxed. This theory (here termed ‘niche-packing equivalence’) predicts that the evolution of ecological sexual dimorphism constrains the ecological opportunity that would otherwise lead to ecological speciation or colonization, and that saturation of niches by different species constrains divergent selection for divergence between the sexes. Therefore, sexes and species are equivalent, yet antagonistic units of niche occupation. We present the most comprehensive test of the niche-packing equivalence theory at ecological time-scales (assemblage level) to date. Location: South America Major taxa studied: Liolaemus lizards. Methods: We identified 23 Liolaemus assemblages varying in species richness and sexual size dimorphism (SSD), distributed across a wide environmental range. We used mixed effects models, permutation tests and Markov Chain Monte Carlo (MCMC) regressions to quantify the relationship between SSD and species richness. We then partitioned the body size niche dimension between the sexes and amongst species, and tested for non-overlapping body size distributions. We regressed SSD and species richness of each assemblage against environmental predictors, using multi-model inference and structural equation modelling. Results: Sexual dimorphism declines with increasing species richness, and a strong signal of tension between the two remains following phylogenetic control. This pattern is accompanied by evidence of constraints on body-size partitioning amongst species and between the sexes: the two units of niche saturation tend not to overlap. However, across assemblages, species richness and SSD correlate with different environmental variables, suggesting th

Phylogeography can provide insight into the potential for speciation and identify geographic regions and evolutionary processes associated with species richness and evolutionary endemism. In the marine environment, highly mobile species sometimes show structured patterns of diversity, but the processes isolating populations and promoting differentiation are often unclear. The Delphinidae (oceanic dolphins) are a striking case in point and, in particular, bottlenose dolphins (Tursiops spp.). Understanding the radiation of species in this genus is likely to provide broader inference about the processes that determine patterns of biogeography and speciation, because both fine-scale structure over a range of kilometers and relative panmixia over an oceanic range are known for Tursiops populations. In our study, novel Tursiops spp. sequences from the northwest Indian Ocean (including mitogenomes and two nuDNA loci) are included in a worldwide Tursiops spp. phylogeographic analysis. We discover a new ‘aduncus’ type lineage in the Arabian Sea (off India, Pakistan and Oman) that diverged from the Australasian lineage ∼261 Ka. Effective management of coastal dolphins in the region will need to consider this new lineage as an evolutionarily significant unit. We propose that the establishment of this lineage could have been in response to climate change during the Pleistocene and show data supporting hypotheses for multiple divergence events, including vicariance across the Indo-Pacific barrier and in the northwest Indian Ocean. These data provide valuable transferable inference on the potential mechanisms for population and species differentiation across this geographic range.

Critical thermal limits (CTLs) are established viability thresholds when studying the impact of climate change on natural populations. Novel ‘thermal fertility limits’ of species have been proposed alongside CTLs, to better assess the sublethal effects of rising temperatures on species persistence. However, sex-specific sensitivity of fertility to temperature also needs consideration.

In the commercial and medical sectors, 3D printing is delivering on its promise to en‐ able a revolution. However, in the fields of Ecology and Evolution we are only on the brink of embracing the advantages that 3D printing can offer. Here we discuss exam‐ ples where the process has enabled researchers to develop new techniques, work with novel species, and to enhance the impact of outreach activities. Our aim is to showcase the potential that 3D printing offers in terms of improved experimental techniques, greater flexibility, reduced costs and promoting open science, while also discussing its limitations. By taking a general overview of studies using the technique from fields across the broad range of Ecology and Evolution, we show the flexibility of 3D printing technology and aim to inspire the next generation of discoveries.

Curved-rods are a ubiquitous bacterial phenotype, but the fundamental question of why they are shaped this way remains unanswered. Through in silico experiments, we assessed freely swimming straight- and curved-rod bacteria of a wide diversity of equal-volume shapes parameterized by elongation and curvature, and predicted their performances in tasks likely to strongly influence overall fitness. Performance tradeoffs between these tasks lead to a variety of shapes that are Pareto-optimal, including coccoids, all straight rods, and a range of curvatures. Comparison with an extensive morphological survey of motile curved-rod bacteria indicates that the vast majority of species fall within the Pareto-optimal region of morphospace. This result is consistent with evolutionary tradeoffs between just three tasks: efficient swimming, chemotaxis, and low cell construction cost. We thus reveal the underlying selective pressures driving morphological diversity in a wide-spread component of microbial ecosystems.