Three new species of Hatschekia Poche, 1902 (Copepoda: Siphonostomatoida: Hatschekiidae) parasitic on Abalistes filamentosus (Pisces: Tetraodontiformes: Balistidae) from off Okinawa, Japan.

Three new species of the copepod genus Hatschekia Poche, 1902, H. lima n. sp., H. cylindrus n. sp. and H. sunaoi n. sp., are described from the gill filaments of a triggerfish, Abalistes filamentosus Matsuura & Yoshino, caught off the Ryukyu Islands, Okinawa, Japan. These new species share an unusual morphological character, i.e. four stout posterior spines on the intercoxal sclerites of legs 1 and 2. H. lima n. sp. differs from its congeners in having a robust inner lobe on the maxillule and leg 3 with a swollen basal lobe. H. cylindrus n. sp. is distinguishable from its congeners by having a cephalothorax fused to the trunk and a double-semicircular chitinous frame. H. sunaoi n. sp. is characterised by leg 3 with a swollen basal lobe and an oval cephalothorax.