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Most of life's vast diversity of species and phenotypes is often attributed to adaptive radiation. Yet its contribution to species and phenotypic diversity of a major group has not been examined. Two key questions remain unresolved. First, what proportion of clades show macroevolutionary dynamics similar to adaptive radiations? Second, what proportion of overall species richness and phenotypic diversity do these adaptive-radiation-like clades contain? We address these questions with phylogenetic and morphological data for 1226 frog species across 43 families (which represent >99% of all species). Less than half of frog families resembled adaptive radiations (with rapid diversification and morphological evolution). Yet, these adaptive-radiation-like clades encompassed ~75% of both morphological and species diversity, despite rapid rates in other clades (e.g., non-adaptive radiations). Overall, we support the importance of adaptive-radiation-like evolution for explaining diversity patterns and provide a framework for characterizing macroevolutionary dynamics and diversity patterns in other groups.

ABSTRACT Aim Location Time Period Major Taxa Studied Methods Results Main Conclusions Diet is a key aspect of life in animals. There have been numerous independent origins of herbivorous diet across animals, but the factors that explain these origins remain poorly understood. One potentially crucial factor is body temperature (Tb), as the gut‐dwelling bacteria that help digest cellulose in many herbivores are thought to require high temperatures. However, analyses in birds, lizards and mammals found only limited evidence for higher Tb in herbivores than in carnivores. These analyses tested whether diet explains Tb evolution. Here, we focus instead on testing whether Tb helps explain the evolution of diet across tetrapods.Global.Past 350 million years.Tetrapods.We analysed 1712 species with matched data on diet and Tb using diverse phylogenetic methods.Ancestral reconstructions indicated that tetrapods likely had a carnivorous ancestor, followed by repeated transitions to omnivory and herbivory, especially in the last 110 million years. Thus, extant herbivorous lineages in tetrapods are relatively young, in contrast to many older carnivorous lineages. They are also relatively unstable in that reversals from herbivory back to omnivory and from omnivory back to carnivory were as frequent as the origins of herbivory and omnivory. Using phylogenetic logistic regression, we support the hypothesis that higher Tb helps explain the evolution of herbivory across tetrapods and within birds, mammals, lepidosaurs and turtles. Phylogenetic path analyses suggest that Tb generally drives the evolution of herbivory, and not vice versa. Our analyses also suggest that Tb is more important for the evolution of herbivory than large body size or diurnal diel activity, which are both significant predictors of herbivory in some cases.Our results show for the first time that Tb is a significant predictor of diet evolution among and within many major animal clades. [ABSTRACT FROM AUTHOR]

Aim: The climatic niche is associated with diversification in many groups of animals and plants. However, the relationships between climatic‐niche breadth evolution, climatic‐niche position evolution, and speciation remain underexplored. It is particularly unclear whether changes in climatic‐niche breadth are related to diversification. We tested two hypotheses relating niche breadth, niche position, and speciation using climatic data in Squamata (lizards and snakes), one of the largest radiations of tetrapods. These hypotheses were: (1) the oscillation hypothesis (niche breadth changes along with niche position and speciation) and (2) the musical‐chairs hypothesis (niche breadth remains relatively constant when niche position changes during speciation). Location: Global. Taxon: Squamata (lizards and snakes). Methods: We estimated rates of speciation and evolutionary rates for both climatic‐niche position and climatic‐niche breadth for 5320 squamate species. We tested relationships among these rates using Bayesian phylogenetic generalised linear‐mixed models. Results: Higher speciation rates were associated with higher rates of evolution in niche position and in niche breadth. Faster rates of change in niche breadth were related to narrower niches and faster rates of change in niche position. Main Conclusions: Our results support the oscillation hypothesis to explain the relationships between speciation and changes in climatic‐niche position and climatic‐niche breadth. We found that species that changed climatic‐niche breadths more rapidly: (1) speciated faster; (2) evolved towards narrower niche breadths; and (3) changed climatic‐niche positions more rapidly. These results suggest that oscillation between wider and narrower niches is coupled with climatic‐niche divergence and speciation. These conclusions may apply to many other groups of plants and animals in which speciation is often related to climatic‐niche divergence. [ABSTRACT FROM AUTHOR]

Insects contain more than half of all living species, but the causes of their remarkable diversity remain poorly understood. Many authors have suggested that herbivory has accelerated diversification in many insect clades. However, others have questioned the role of herbivory in insect diversification. Here, we test the relationships between herbivory and insect diversification across multiple scales. We find a strong, positive relationship between herbivory and diversification among insect orders. However, herbivory explains less variation in diversification within some orders (Diptera, Hemiptera) or shows no significant relationship with diversification in others (Coleoptera, Hymenoptera, Orthoptera). Thus, we support the overall importance of herbivory for insect diversification, but also show that its impacts can vary across scales and clades. In summary, our results illuminate the causes of species richness patterns in a group containing most living species, and show the importance of ecological impacts on diversification in explaining the diversity of life.

Among direct-developing rain frogs of the genus Craugastor is a clade of 19 described species (bocourti series) that occur in Mexico and northern Central America. Many of these 19 species have been described based on subtle morphological differences and have never been examined using molecular data. Here, we used a multilocus dataset (one mitochondrial (mtDNA) and four nuclear (nDNA) gene fragments, totalling 3,048 concatenated base pairs) to investigate species limits and phylogenetic relationships among 60 northern rain frogs referable to 12 species, with a focus on species from Guatemala. We inferred phylogenies using maximum likelihood and Bayesian analyses on separate mtDNA and nDNA datasets. Concatenated and coalescent species-tree analyses support the monophyly of multiple species, with interspecific relationships mostly unresolved. These mtDNA and nDNA trees were often incongruent with morphology-based taxonomy. For example, two genetically shallow clades contained individuals referable to at least five described species, whereas a single described species contained deep divergences indicative of multiple cryptic species. These findings indicate that morphology-based taxonomy has both overestimated and underestimated actual species diversity (depending on the species), an interpretation supported by two molecular species-delimitation procedures. Based on these findings, we synonymise C. glaucus (Lynch, 1967) and C. stuarti (Lynch, 1967) with C. xucanebi (Stuart, 1941). We also synonymise C. nefrens (Smith, 2005) and C. cyanochthebius McCranie & Smith, 2006 with C. campbelli (Smith, 2005). The molecular data also support multiple undescribed species, notably within C. decoratus (Taylor, 1942). Overall, we show how morphology-based species delimitation can both underestimate and overestimate species richness in morphologically conservative groups. [ABSTRACT FROM AUTHOR]

Phylogenetic and phylogeographic approaches have become widespread in evolutionary biology, ecology, and biogeography.  However, analyses that incorporate inferences from historical biogeography (e.g. timing of colonization of a region) may be essential to answer the most important large-scale questions in these fields, but they remain infrequently used.  I focus on two examples here.  First, I argue that understanding the origins of biodiversity hotspots (and other high-diversity regions) requires comparing the timing of biogeographic colonization and diversification rates among regions.  In contrast, phylogeographic studies (analyses within species within a region) may themselves say little about why a region is diverse relative to others.  Second, incorporating historical biogeograpy can help address the processes that determine community species richness and structure, such as dispersal, in-situ trait evolution, and in-situ speciation.  In contrast, the widespread “community phylogenetics” approach (focusing on relatedness of species in communities) may have limited ability to explain community richness and structure.