Morphometric variability among the species of the Sordida subcomplex (Hemiptera: Reduviidae: Triatominae): evidence for differentiation across the distribution range of Triatoma sordida.

NATTERO J; PICCINALI R; MACEDO C; HERNÁNDEZ M L; ABRAHAN L; LOBBIA P; RODRÍGUEZ C; CARBAJAL DE LA FUENTE AL

PARASITES AND VECTORS

BIOMED CENTRAL LTD

Lugar: Londres; Año: 2017

1756-3305

The Sordida subcomplex (Triatominae) comprises four species, Triatomagarciabesi, T. guasayana, T. patagonica and T. sordida, which differ in epidemiologicalimportance and adaptations to human environments. Some morphological similaritiesamong species make taxonomic identification, population differentiation and speciesdelimitation controversial. Triatoma garciabesi and T. sordida are the most similarspecies, having been considered alternatively two and a single species until T.garciabesi was re-validated, mostly based on the morphology of male genitalia. Morerecently, T. sordida from Argentina has been proposed as a new cryptic speciesdistinguishable from T. sordida from Brazil, Bolivia and Paraguay by cytogenetics. Westudied linear and geometric morphometry of the head, wings and pronotum inpopulations of these species aiming to find phenotypic markers for their discrimination,especially between T. sordida and T. garciabesi, and if any set of variables thatvalidates T. sordida from Argentina as a new species.Results: Head width and pronotum length were the linear variables that bestdifferentiated species. Geometric morphometry revealed significant Mahalanobisdistances in wing shape between all pairwise comparisons. Triatoma patagonicaexhibited the best discrimination and T. garciabesi overlapped the distribution of theother species in the morphometric space of the first two DFA axes. Head shapeshowed differentiation between all pairs of species except for T. garciabesi and T.sordida. Pronotum shape did not differentiate T. garciabesi from T. guasayana. Thecomparison between T. garciabesi and T. sordida from Argentina and T. sordida fromBrazil and Bolivia revealed low differentiation based on head and pronotum linearmeasurements. Pronotum and wing shape were different between T. garciabesi and T.sordida from Brazil and Bolivia and T. sordida from Argentina. Head shape did notdifferentiate T. garciabesi from T. sordida from Argentina.Conclusions: Wing shape best delimited the four species phenotypically. The proposedcryptic species, T. sordida from Argentina, differed from T. sordida from Brazil andBolivia in all measured shape traits, suggesting that the putative new species may notbe cryptic. Additional studies integrating cytogenetic, phenotypic and molecularmarkers, as well as cross-breeding experiments are needed to confirm if these threeentities represent true biological species.