Females: P2-P4 Exp1 without inner seta; P3 Exp3 without such spinules on outer margin. More characters can be accessed by backtracking the key: Page 1240
Males: Anal somite longer than CR. More characters can be accessed by backtracking the key: Page 1270
Kingdom Animalia Phylum Crustacea Class Maxillopoda Subclass Copepoda Order Cyclopoida Family Oithonidae Genus Oithona Species Oithona frigida
