Triatoma pintodiasi (Hemiptera: Reduviidae: Triatominae), new cryptic species vector of the Chagas' disease from southern South America

Chagas’ disease continues being a scourge for the poor population from 21 countries in America, where 100 million people live under risk, and about 8 million might be infected with a still incurable illness. During a field trip in search of vectors of Chagas’ disease on the locality of Rincão Nossa Senhora das Graças, Caçapava do Sul Municipality, Rio Grande do Sul State, Brazil (30º30’58” S / 53º29’12” W), 14 specimens of triatomines have been collected on a stone fence. The general coloration of the insects is strikingly similar to that of Triatoma carcavalloi, but they show distinctly smaller size. The same specimens result in T. circummaculata on available keys, but do not fit on the chromatic and morphological standards of the species. After comparison with the types of both similar species, it was possible to determine that the material is representative of a new cryptic species of the T. rubrovaria subcomplex. Types of the new species have been deposited on the Triatomines Collection of the Oswaldo Cruz Institute. Besides the description of the general color, morphology and of male genitalia, morphometric analysis of the head of Triatoma pintodiasi, T. rubrovaria, T. carcavalloi, and T. circummaculata, and an analysis of the hemolymph proteins of Triatoma pintodiasi and T. circummaculata have been made in order to provide substantial support for the new species. The results of the morphometric analysis show that the first two principal components represent 73.2% of the total variability (PC1 = 51.7% and PC2 = 21.5%). Triatoma rubrovaria can be distinguished from other species on a factorial map based on PC1, whereas the other species are distinguished by PC2, and all species are further separated by an analysis of canonic components. As for the hemolymph, the electrophoresis revealed significant differences between the proteins of the new species and T. circummaculata, with those of 4 KDa, 60 KDa, and 120 KDa being more abundant on the former.