Combined phylogenetic and morphometric information to delimit and unify the Triatoma brasiliensis species complex and the Brasiliensis subcomplex.

"Triatoma brasiliensis species complex" was defined as a monophyletic group of the species: T. brasiliensis, T. juazeirensis, T. melanica, and T. sherlocki. An alternative grouping scheme proposed the concept of "Brasiliensis subcomplex" which included the former species together with T. melanocephala, T. petrocchiae, T. lenti, T. tibiamaculata, and T. vitticeps. To evaluate the relationship among these taxa we combined the results obtained with four mitochondrial genes (12S, 16S, COI and Cytb, adding to 1811bp) and geometric morphometric analysis of wings and heads. Panstrongylus megistus was included in the analysis as it was previously found related to T. tibiamaculata, T. melanocephala and T. vitticeps. The results of both molecular and morphometric approaches clearly grouped the species analyzed into two monophyletic units, supported by both genetic and wing variability. The first one (G1) comprises the four species originally included in the T. brasiliensis species complex plus T. lenti and T. petrocchiae. The second group (G2) was composed by T. melanocephala, T. tibiamaculata and T. vitticeps, and remarkably, P. megistus if considering wing variability and phylogenetic results. Nevertheless, geometric morphometrics of heads provided a quantitative measurement that discriminates Panstrongylus from the Triatoma species based on the position of the antennal insertion relative to eyes, as it is used as the generic distinctive character. The discrepancy among approaches questions the validity of this character to define Panstrongylus genus. Independently of the chosen group definition -"T. brasiliensis species complex" or "Brasiliensis subcomplex"-we propose to delimit it to species of G1 that are all associated with the Caatinga biome in the Brazilian Northeast. G2 are the ones associated with the Atlantic Forest biome.

Genome size determination in chagas disease transmitting bugs (hemiptera-triatominae) by flow cytometry.

Because information about genome size in triatomines is scarce and contradictory, we performed DNA quantification by flow cytometry in 13 species belonging to five genera (Dipetalogaster, Eratyrus, Panstrongylus, Rhodnius, and Triatoma) to infer overall tendencies and phylogenetic associations. The results show that the haploid DNA content of the subfamily Triatominae varies nearly 4-fold, from<0.7 pg in Rhodnius species (0.6x10(9) bp) to 2.7 pg in Triatoma delpontei (2.6x10(9) bp). Considering that triatomines present similar chromosome numbers, we suggest that genome size differences are the result of variation in the quantity of repetitive DNA sequences localized in hetero and euchromatin. Changes in heterochromatin are particularly important when considering populations or closely related species; in more distant taxa, euchromatic changes also play a role. Our analyses indicate that flow cytometry is a useful tool for population, taxonomic, and evolutionary studies in this subfamily.