Karyotype of Triatoma melanocephala Neiva and Pinto (1923). Does this species fit in the Brasiliensis subcomplex?

Triatoma melanocephala is a rare species of Hemiptera that belongs to the Brasiliensis subcomplex. This subcomplex is composed of cryptic species, and the basic number of chromosomes for triatomines of this subcomplex is 2n = 22; however, T. melanocephala showed a karyotype of 2n = 24 (20A + X(1)X(2)X(3)Y). Thus, this study allowed us to describe the karyotype of the species and, more specifically, to propose the exclusion of T. melanocephala, as well as T. vitticeps and T. tibiamaculata, which also has fragmentation of the X chromosome, from the Brasiliensis subcomplex.