Four katydid species are treated taxonomically and/or acoustically. Two new species of Ecuaneduba are described from Colombia: E. gambitaensis sp. nov. and E. inzaensis sp. nov. A closely related new species from Ecuador is placed in a new cognate genus: Acanthoraculus milagro gen. et sp. nov.; its call is analysed and also the calls of Ecuaneduba aequatorialis. Since these genera, Ecuaneduba and Acanthoraculus, comprise at present the only New World representatives of the subfamily Hexacentrinae, we include them in their own tribe Ecuanedubini. A similar situation exists for a small group of Mecopodinae, for which the tribe Tabariini is proposed. Pronotal shapes, subnotal and subtegminal spaces — adapted for sound generation — are diverse in these four taxa; costal fields may function as acoustic baffles that reduce short-circuiting.