1. Sexual dimorphism in morphology of rostral seta absent; head of bothridial seta not covered by anterior margin of notogaster or covered partially (up to one third); rostrum tripartite; sejugal apodeme directed to posterior half of genital plate; distance between adanal setae ad 1 – ad 2 equal to ad 2 – ad 3; body length: 270–285................. Symbioribates tripartitus sp. nov.
- Sexual dimorphism in morphology of rostral seta present (thick in male versus setiform in female); head of bothridial seta completely or partially (up to half) covered by anterior margin of notogaster; rostrum rounded or truncate; sejugal apodeme directed to anterior half or middle of genital plate; distance between adanal setae ad 1 – ad 2 shorter than ad 2 – ad 3........... 2