Caligus Muller 1785

An updated key to the species groups currently recognized within Caligus based on that of Ohtsuka & Boxshall (2019). 1 Leg 1 with 3 inner setae on distal exopod segment lost or highly reduced.......................... C. productus group - Leg 1 with 3 inner setae on distal exopod segment well developed............................................. .. 2 2 Large denticles present along outer margin of second endopod segment of leg 2........................ C. bonito group - Large denticles absent along outer margin of second endopod segment of leg 2.................................... .. 3 3 Leg 4 is 3-segmented with I, I, III spines.................................................................. .. 4 - Leg 4 is 3-segmented, compound segment with only 3 terminal spines............................................ 5 4 Long-bodies; apron of leg 3 with raised bifid cuticular rib and rosette-like array of denticles......... .... C. confusus group - Compact bodies; apron of leg 3 without such ornamentation.................................. .. C. diaphanus group 5 Distal compound exopod segment of leg 4 with 1 outer and 3 terminal spines..................................... .. 6 - Distal compound exopod segment of leg 4 with 3 terminal spines................................ C. macarovi group 6 Genital complex longer than wide, leg 2 distal exopodal segment with reduced or small outer spine..... C. undulatus group - Genital complex as long as wide without posterolateral lobes and about twice as long as abdomen, leg 2 distal exopodal segment with reduced outer spine and small adjacent spine................................. C. pseudorhombi group