Ohtsuka & Kimoto 1989. Tortanus (Atortus) (Copepoda: Calanoida) of southern Japanese waters, with description of two new species T. (A.) digitalis and T. (A.) ryukyuensis, and discussion on distribution and swarming behavior of Atortus. Journal of Crustacean Biology, 9(3) 1989: 392-408