Aim Multiple biogeographical scenarios involving vicariance and different colonization routes can explain disjunct species distributions in the Southern Hemisphere. Here, we tested several alternative hypotheses in Eneopterinae crickets, a diverse subfamily presenting a disjunct worldwide distribution. We inferred a dated phylogeny of Eneopterinae and reconstructed their biogeographical history to unravel the origin of their present-day distribution, focusing on their multiple origins in the Neotropics.Location Worldwide.Methods We sampled 62 eneopterine species representing all extant genera. We inferred their phylogenetic relationships through Bayesian and maximum likelihood approaches based on four mitochondrial and three nuclear gene sequences. Divergence time estimates were inferred using Bayesian relaxed clock approaches and primary fossil calibrations. Biogeographical analyses were conducted with the default dispersal-extinction-cladogenesis (DEC) model and a variant model (DEC+J), which accounts for rare-jump dispersal events. ResultsOur dating analyses showed that the Eneopterinae is far older than expected and its diversification can be traced back to the Late Cretaceous (c. 76 Ma). In this context, the most supported biogeographical scenario (under DEC+J) suggests that the Neotropics were colonized twice independently: first during the break-up of Gondwana, when Antarctica, Australia and South America started separating (compatible with a vicariance event if relying on the result of the DEC model alone); later through a northern recolonization originating from Southeast Asia, likely related to a Holarctic Boreotropical distribution of an eneopterine lineage during the Eocene. Main conclusionsWe provided a dated worldwide biogeographical framework for the Eneopterinae crickets. Overall, the subfamily disjunct distribution pattern is better explained by both ancient and recent dispersal events. Whether this could reflect a widespread pattern in insect groups exhibiting a disjunct distribution remains to be investigated by studying other insect lineages. The information gathered here will also help foster new directions for future studies concerning the acoustic innovations of this clade.We used the software Muscle (Edgar, 2004) with default parameters, implemented in Mega 6.0 (Tamura et al., 2013) to align the sequences. With Mega, we also checked if the protein-coding genes were congruent with codon reading frames. We conducted preliminary maximum likelihood

One of the long-standing paradoxes in genomic evolution is the observation that much of the genome is composed of repetitive DNA which has been typically regarded as superfluous to the function of the genome in generating phenotypes. In this work, we used comparative phylogenetic approaches to investigate if the variations in genome sizes (GS) should be considered as adaptive or neutral processes by the comparison between GS and flower diameters (FD) of 50 Passiflora species, more specifically, within its two most species-rich subgenera, Passiflora and Decaloba. For this, we have constructed a phylogenetic tree of these species, estimated GS and FD of them, inferred the tempo and mode of evolution of these traits and their correlations, using both current and phylogenetically independent contrasted values. We found significant correlations among the traits, when considering the complete set of data or only the subgenus Passiflora, whereas no correlations were observed within Decaloba. Herein, we present convincing evidence of adaptive evolution of GS, as well as clues that this pattern is limited by a minimum genome size, which could reduce both the possibilities of changes in GS and the possibility of phenotypic responses to environment changes.

Aim  The aim of this study was to assess the causal mechanisms underlying populational subdivision in Drosophila gouveai, a cactophilic species associated with xeric vegetation enclaves in eastern Brazil. A secondary aim was to investigate the genetic effects of Pleistocene climatic fluctuations on these environments. Location  Dry vegetation enclaves within the limits of the Cerrado domain in eastern Brazil. Methods  We determined the mitochondrial DNA haplotypes of 55 individuals (representing 12 populations) based on sequence data of a 483‐bp fragment from the cytochrome c oxidase subunit II (COII) gene. Phylogenetic and coalescent analyses were used to test for the occurrence of demographic events and to infer the time of divergence amongst genetically independent groups. Results  Our analyses revealed the existence of two divergent subclades (G1 and G2) plus an introgressed clade restricted to the southernmost range of D. gouveai. Subclades G1 and G2 displayed genetic footprints of range expansion and segregated geographical distributions in south‐eastern and some central highland regions, east and west of the Paraná River valley. Molecular dating indicated that the main demographic and diversification events occurred in the late to middle Pleistocene. Main conclusions  The phylogeographical and genetic patterns observed for D. gouveai in this study are consistent with changes in the distribution of dry vegetation in eastern Brazil. All of the estimates obtained by molecular dating indicate that range expansion and isolation pre‐dated the Last Glacial Maximum, occurring during the late to middle Pleistocene, and were probably triggered by climatic changes during the Pleistocene. The current patchy geographical distribution and population subdivision in D. gouveai is apparently closely linked to these past events.

The transition from unicellular to multicellular organisms poses the question as to when genes that regulate cell-cell interactions emerged during evolution. The receptor and ligand pairing of plexins and semaphorins regulates cellular interactions in a wide range of developmental and physiological contexts. We surveyed here genomes of unicellular eukaryotes and of non-bilaterian and bilaterian Metazoa and performed phylogenetic analyses to gain insight into the evolution of plexin and semaphorin families. Remarkably, we detected plexins and semaphorins in unicellular choanoflagellates, indicating their evolutionary origin in a common ancestor of Choanoflagellida and Metazoa. The plexin domain structure is conserved throughout all clades; in contrast, semaphorins are structurally diverse. Choanoflagellate semaphorins are transmembrane proteins with multiple fibronectin type III domains following the N-terminal Sema domain (termed Sema-FN). Other previously not yet described semaphorin classes include semaphorins of Ctenophora with tandem immunoglobulin domains (Sema-IG) and secreted semaphorins of Echinoderamata (Sema-SP, Sema-SI). Our study also identified Met receptor tyrosine kinases (RTKs), which carry a truncated plexin extracellular domain, in several bilaterian clades, indicating evolutionary origin in a common ancestor of Bilateria. In addition, a novel type of Met-like RTK with a complete plexin extracellular domain was detected in Lophotrochozoa and Echinodermata (termed Met-LP RTK). Our findings are consistent with an ancient function of plexins and semaphorins in regulating cytoskeletal dynamics and cell adhesion that predates their role as axon guidance molecules.

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