Phylogeny of the Drosophila mesophragmatica group (Diptera, Drosophilidae): an example of Andean evolution

Unveiling the Mycodrosophila projectans (Diptera, Drosophilidae) species complex: Insights into the evolution of three Neotropical cryptic and syntopic species

The Zygothrica genus group has been shown to be speciose, with a high number of cryptic species. DNA barcoding approaches have been a valuable tool to uncover cryptic diversity in this lineage, as recently suggested for the Neotropical Mycodrosophila projectans complex, which seems to comprise at least three different species. The aim of this study was to confirm the subdivision of the M. projectans complex while shedding some light on the patterns and processes related to its diversification. In this sense, the use of single and multi-locus datasets under phylogenetic, distance, coalescence, and diagnostic nucleotide approaches confirmed the presence of at least three species under the general morphotype previously described as M. projectans. Only a few subtle morphological differences were found for the three species in terms of aedeagus morphology and abdominal color patterns. Ecologically, sympatry and syntopy seem to be recurrent for these three cryptic species, which present widely overlapping niches, implying niche conservatism. This morphological and ecological similarity has persisted though cladogenesis within the complex, which dates back to the Miocene, providing an interesting example of morphological conservation despite ancient divergence. These results, in addition to contrasting patterns of past demographic fluctuations, allowed us to hypothesize patterns of allopatric or parapatric diversification with secondary contact in Southern Brazil. Nevertheless, genetic diversity was generally high within species, suggesting that migration may encompass an adaptive response to the restrictions imposed by the ephemerality of resources.

Phylogeny of the Genus Drosophila

Understanding phylogenetic relationships among taxa is key to designing and implementing comparative analyses. The genus Drosophila, which contains over 1600 species, is one of the most important model systems in the biological sciences. For over a century, one species in this group, Drosophila melanogaster, has been key to studies of animal development and genetics, genome organization and evolution, and human disease. As whole-genome sequencing becomes more cost-effective, there is increasing interest in other members of this morphologically, ecologically, and behaviorally diverse genus. Phylogenetic relationships within Drosophila are complicated, and the goal of this paper is to provide a review of the recent taxonomic changes and phylogenetic relationships in this genus to aid in further comparative studies.

Cinco especies nuevas del género Drosophila(Diptera, Drosophilidae) en la provincia de Napo, Ecuador

RESUMEN Se encontraron cuatro especies nuevas en tres localidades en la provincia de Napo, Ecuador. Los individuos fueron colectados en tres altitudes 1.700 m, 2.200 m y 3.362 m. En todos los muestreos se utilizaron trampas fabricadas con botellas de plástico que contenían cebo (pedazos de plátano previamente fermentados con levadura). Las especies pertenecen a los grupos Drosophila mesophragmatica (D. neoamaguana sp. nov. y D. neoyanayuyu sp. nov.), Drosophila canalinea (D. cosanga sp. nov.) y Drosophila saltans (D. neoprosaltans sp. nov.); además D. guacamayos sp. nov. que por el momento no se encuentra relacionada a ningún grupo de especies de Drosophila.

hobo-brothers elements and their time and place for horizontal transfer

Transposable elements (TEs) are ubiquitous components of nearly all genomes studied. These elements are highly variable in copy number, molecular structure and transposition strategies. They can move within and between genomes, thus increasing their copy numbers and avoiding being eliminated by stochastic and deterministic processes. hobo is a class II element isolated from Drosophila melanogaster. Previous phylogenetic analyses have shown that the canonical hobo element from D. melanogaster has a sister group formed by sequences found in D. willistoni (called howilli2) and D. mojavensis (called homo1). In the present study, we investigated 36 Drosophilidae species for sequences similar to howilli2 and homo1 using degenerate primers. Additionally, in silico searches were performed in 21 available Drosophila genomes. The obtained sequences formed a monophyletic sister group with the canonical hobo element; we termed these sequences 'hobo-brothers' elements. These elements showed a patch distribution and incongruities with the TE and host species phylogenies, suggesting possible cases of horizontal transfer (HT). Species that possess hobo-brothers sequences are from the New World, mainly Neotropical areas. In addition, the estimated divergence of the sequences found showed that these elements are or were recently active; the large number of HT events observed suggests that these elements could be experiencing an expansion process in Neotropical genomes. A comparison of these results with the literature is discussed with regard to the importance of the time and location of horizontal transposon transfer events.

Cuatro especies nuevas del grupo de especies Drosophila mesophragmatica (Diptera, Drosophilidae) de los Andes ecuatorianos

Se describen cuatro especies nuevas del grupo Drosophila mesophragmatica. Las nuevas especies fueron descubiertas en los páramos y remanentes de bosque andino de los Andes ecuatorianos. Las capturas fueron realizadas desde los 2200 hasta los 4000 m de altitud. Las especies nuevas son: D. cashapamba sp. nov., D. chorlavi sp. nov., D. rucux sp. nov. y D. yanayuyu sp. nov. Con las cuatro especies nuevas descubiertas, el número de especies dentro del grupo D. mesophragmatica se incrementa a 17. Los miembros del grupo están distribuidos principalmente en los Andes sudamericanos.

Phylogenetic relationships and macro-evolutionary patterns within the Drosophila tripunctata "radiation" (Diptera: Drosophilidae)

Despite previous efforts, the evolutionary history of the immigrans-tripunctata clade remains obscure in part due to its hypothesized origin through a rapid radiation. We performed a supermatrix analysis (3,243 base pairs) coupled with richness patterns, environmental phylogenetic signal and radiation tests in order to address phylogenetic relationships and macro-evolutionary hypotheses within this complex group of species. We propose a well-supported evolutionary scenario for the immigrans-tripunctata clade species, in which the tripunctata "radiation" was monophyletic and subdivided into three main lineages: the first including D. pallidipennis (pallidipennis group) imbedded among members of the tripunctata group; the second clustering the cardini and guarani groups; and the third grouping representatives from the tripunctata, calloptera and guaramunu groups. Therefore, we hypothesize that the tripunctata group encompasses a diphyletic taxon, with one clade including the pallidipennis group and the other showing a close affinity to the calloptera and guaramunu groups. Our results also suggest that niche evolution seems to have played a central role in the evolutionary history of the tripunctata species "radiation" allowing effective dispersion and diversification in the Neotropics, possibly in a southwards direction. Although the data as a whole support the notion that this occurred through rapid and successive speciation events, the radiation hypothesis remains to be further corroborated.