Invasive ants are usually harmful taxa and considered a potential problem to biodiversity due to their negative ecological impacts, as they can exclude native ant species. Ten such species are reported for Brazil. In this study, we report for the first time the Asian tramp ant Technomyrmex vitiensis Mann, 1921 at the municipality of Oiapoque, in the Brazilian Amazon. The studied colony contained workers, intercastes, males and larvae and provided sperm structure and cytogenetic data. Considering the unprecedented report of the genus Technomyrmex as well as the recent finding of the primarily Australian genus Leptomyrmex in Brazil, we present a revised key for the workers of Brazilian Dolichoderinae genera. Technomyrmex vitiensis presented 2n = 16 chromosomes, all metacentrics and comparative cytogenetics in the genus is provided. A single rDNA 18S site located in intrachromosomal region was observed in this species, which is a common trait in ants. The spermatozoa of T. vitiensis showed filiform shape, with 78.13 (± 1.96) µm of total length and 11.43(± 0.51) µm of nucleus length. Total and nucleus sperm size length fit with the known variation observed in other ant species. The occurrence of T. vitiensis in Brazil is probably a result of traffic between French Guiana and the Amapá state. Cytogenetic and sperm structure of T. vitiensis enhance the biological knowledge of this tramp species. We highlight the scarce knowledge of ant diversity in the state of Amapá and the potential consequences of the presence of the species in the region.