One new species and two new subspecies of fleas are described. These are S. sulawesiensis n. sp. from North and Central Sulawesi, S. alticola pilosus n. ssp. from Central Sulawesi, and S. alticola crassinavis n. ssp. from North Sulawesi. All three of these new taxa are ectoparasites of native, endemic murine rodents. Two of the new taxa, S. sulawesiensis and S. alticola crassinavis, coexist on the same mountain, Gunung Moajat, in North Sulawesi. The related S. alticola alticola, which becomes the nominate subspecies, parasitises the murine rodent Maxomys alticola in northern Borneo (Sabah) and it is hypothesized that Sigmactenus first colonized Sulawesi as an ectoparasite of ancestral Maxomys, or perhaps Rattus, as these murines dispersed from southeast Asia to Sulawesi; 15 endemic murine rodent species belonging to these two genera are known to currently inhabit Sulawesi. An identification key and distribution map are included for all known species and subspecies of Sigmactenus. In addition to the three new taxa and S. a. alticola, these include: S. celebensis from South Sulawesi, S. timorensis from Timor, S. toxopeusi from New Guinea, and S. werneri from the Philippines (Mindanao and Negros).