Phylogeny of the North-Central American clade of blood-sucking reduviid bugs of the tribe Triatomini (Hemiptera: Triatominae) based on the mitochondrial genome.

Triatominae is a subfamily of blood-sucking reduviid hemipterans of public health importance primarily in tropical and sub-tropical regions of the Americas, whose members possess various morphological adaptations closely associated to hematophagy. Despite their medical importance, the systematics of the subfamily is far from resolved, particularly within the tribe Triatomini. Here we employed mitochondrial genome DNA sequences to reconstruct the phylogenetic relationships among 19 species of the North-Central American (NCA) clade of Triatomini and to estimate the times of origin and diversification of its main clades. Twenty-nine mitogenomes were examined for representative specimens of 25 species, including the outgroup. Phylogenetic informativeness estimated for each protein-coding gene showed that cox1, cox2 and atp6 were the most informative markers, whereas atp8 and nad4 had high saturation levels. Phylogenetic analyses excluding the latter two protein-coding genes recovered an almost fully resolved topology. The NCA clade apparently originated shortly after emergence of an initial land bridge of the Panama Isthmus, ca. 15.05-20.05 Mya. An Asian/pantropical subclade with Linshcosteus costalis, Triatoma rubrofasciata and T. migrans was nested within the NCA clade, from which it diverged ca. 12.42-17.3Mya. Uncorrected cox1 and 13 protein-coding gene distances suggest the existence of additional species within the dimidiata complex. In contrast, T. phyllosoma, T. mazzottii and T. longipennis, from the phyllosoma complex, have considerably low cox1 and 13 PCG distances among them, suggesting mitochondrial introgression or conspecificity. Our study yielded a robust phylogeny for the group, which could be tested with further phylogenetic hypotheses based on nuclear genome-wide markers.

3RAD-based systematics of the transitional Nearctic-Neotropical lubber grasshopper genus Taeniopoda (Orthoptera: Romaleidae).

The genus Taeniopoda Stål (Romaleidae) is a group of Nearctic-Neotropical grasshoppers whose systematics has been largely neglected. A recent phylogenetic study based on morphology and mitochondrial and nuclear markers failed to resolve the species boundaries in this genus and showed a lack of reciprocal exclusivity between T. eques (Burmeister) and T. tamaulipensis Rehn. Here we assessed the species limits and phylogenetic relationships in Taeniopoda based on 3RAD data, and evaluated the presence of gene flow and niche overlap between the above two species using clustering and ecological niche modelling (ENM) analyses to determine their taxonomic status. We performed de novo assembly of different 3RAD data sets with distinct parameters settings to explore whether they impact the recovered relationships. Ten species were consistently delimited, with T. picticornis and T. stali regarded as conspecific and the populations of T. auricornis from Guatemala representing a separate species. We maintained the specific status of T. eques and T. tamaulipensis, though our results suggest that they represent a ring species since their genetic composition appear to change gradually following a "loop form" along their geographical distribution. The phylogenomic analyses confirmed the paraphyly of Taeniopoda with respect to Romalea and recovered three major clades. Similar to previous studies, the relationships of our examined matrices were highly congruent despite their different levels of missing data. However, the similarity threshold and minimum number of samples that must share a locus for it to be retained impact the amount of loci and missing data of the matrices. This study demonstrates the utility of 3RAD to detect gene flow and to resolve species limits and phylogenetic relationships among closely related taxa.

Erosion of lizard diversity by climate change and altered thermal niches.

It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.