Quantifying phenotypic evolutionary rates and their variation across phylogenetic trees is a major issue in evolutionary biology. A number of phylogenetic comparative methods (PCMs) currently perform such task. However, available PCMs can locate rate shifts pertaining to entire portions of the phylogeny, but not those expected to occur at the level of individual species and lineages, such as with the idea that body size changes more rapidly in insular vertebrates. Still, most PCMs cannot deal with fossil phylogenies, albeit fossils provide highly desirable information when it comes to understand trait variation and evolution. We developed a PCM based on phylogenetic ridge regression, which we named RRphylo, which assigns an evolutionary rate to each branch of the phylogeny, and is designed to locate rate shifts relating to entire clades, as well as to unrelated tree tips. We tested RRphylo on simulated trees and data to assess its performance under different conditions. Then, we repeated its application with two real case scenarios, the evolution of flight in ornithodirans and mammals and body size evolution in insular mammals, which are usually subsumed to evolve under different range regimes than terrestrial and continental species respectively. RRphylo performs well across all different conditions. The simulation experiments demonstrated it has low Type I and Type II error rate. We found significant evidence that flight accelerates the rate of body size evolution in vertebrates, and that the acquisition of very large body size slows down the rate. Still, insular mammals body size evolution is not faster than in continental species. RRphylo is a new PCM ideal to estimate variation and shift in the rate of phenotypic evolution with fossil data. In addition to testing evolutionary rate variation, it is open to a variety of further questions, such as the evolution of rates in time, the estimation of ancestral states and the estimation of phenotypic trends over time.

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Morphological convergence is an intensely studied macroevolutionary phenomenon. It refers to the morphological resemblance between phylogenetically distant taxa. Currently available methods to explore evolutionary convergence either: rely on the analysis of the phenotypic resemblance between sister clades as compared to their ancestor, fit different evolutionary regimes to different parts of the tree to see whether the same regime explains phenotypic evolution in phylogenetically distant clades, or assess deviations from the congruence between phylogenetic and phenotypic distances. We introduce a new test for morphological convergence working directly with non-ultrametric (i.e. paleontological) as well as ultrametric phylogenies and multivariate data. The method (developed as the function search.conv within the R package RRphylo) tests whether unrelated clades are morphologically more similar to each other than expected by their phylogenetic distance. It additionally permits using known phenotypes as the most recent common ancestors of clades, taking full advantage of fossil information. We assessed the power of search.conv and the incidence of false positives by means of simulations, and then applied it to three well-known and long-discussed cases of (purported) morphological convergence: the evolution of grazing adaptation in the mandible of ungulates with high-crowned molars, the evolution of mandibular shape in sabertooth cats, and the evolution of discrete ecomorphs among anoles of Caribbean islands. The search.conv method was found to be powerful, correctly identifying simulated cases of convergent morphological evolution in 95% of the cases. Type I error rate is as low as 4–6%. We found search.conv is some three orders of magnitude faster than a competing method for testing convergence.

Species introduction represents one of the most serious threats for biodiversity. The realized climatic niche of an invasive species can be used to predict its potential distribution in new areas, providing a basis for screening procedures in the compilation of black and white lists to prevent new introductions. We tested this assertion by modeling the realized climatic niche of the Eastern grey squirrel Sciurus carolinensis. Maxent was used to develop three models: one considering only records from the native range (NRM), a second including records from native and invasive range (NIRM), a third calibrated with invasive occurrences and projected in the native range (RCM). Niche conservatism was tested considering both a niche equivalency and a niche similarity test. NRM failed to predict suitable parts of the currently invaded range in Europe, while RCM underestimated the suitability in the native range. NIRM accurately predicted both the native and invasive range. The niche equivalency hypothesis was rejected due to a significant difference between the grey squirrel’s niche in native and invasive ranges. The niche similarity test yielded no significant results. Our analyses support the hypothesis of a shift in the species’ climatic niche in the area of introductions. Species Distribution Models (SDMs) appear to be a useful tool in the compilation of black lists, allowing identifying areas vulnerable to invasions. We advise caution in the use of SDMs based only on the native range of a species for the compilation of white lists for other geographic areas, due to the significant risk of underestimating its potential invasive range.