Cyclops, Muller, 1776

Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E. & Rudstam, Lars G., 2022, Reevaluation of the genus Cyclops Müller, 1776 (Cyclopoida: Cyclopidae) in the Laurentian Great Lakes basin: first report of the Palearctic species Cyclops divergens Lindberg, 1936 from Lake Erie and documentation of Cyclops sibiricus Lindberg, 1949 in the St. Marys River, Zootaxa 5182 (2), pp. 183-195 : 191-192

Key to Cyclops species of the Laurentian Great Lakes:

1a. Long setules present on proximalmost seta of mxl palp ( Fig. 5b )................................................ 2

1b. Long setules absent on proximalmost seta of mxl palp ( Fig. 2b )................................................. 3

2. A1 extending beyond cephalothorax (female) and A1 first segment densely pitted ( Fig. 3b ), surface of mxl palp ornamented with large spinules ( Fig. 5b ), mxp syncoxopodite with short membranous element featuring prominent distal hook ( Fig. 4b ) and transverse row of small spinules, P1 basipodite medial spine with heteronomous setulation ( Fig. 4c ), P3 coupler unornamented, P4 coupler ornamented with horizontal row of long hairs ( Fig. 5c ), P4 coxopodite ornamented with spinules at positions A, C, D, and E ( Fig. 4d ), P4 coxopodite setae extending beyond medial margin of the basipodite ( Fig. 4e ), P5 basal segment lacking ornamentation................................................................. C. divergens Lindberg, 1936

3a. P4 coxopodite setae unmodified ( Fig. 2f ).................................................................. 4

3b. P4 coxopodite setae proximally swollen................................................................ 5

4. A1not extending beyond cephalothorax (female) andA1 first segment lacking pits ( Fig. 1b ), surface of the mxl palp unornamented or ornamented with only tiny spinules ( Fig. 2b ), mxp syncoxopodite with long membranous element featuring somewhat club shaped distal terminus ( Fig. 2c ) and transverse row of small spinules, P1 basipodite medial spine proximal margin bare ( Fig. 2d ), P3 and P4 coupler ornamented with horizontal row of long hairs, P4 coxopodite ornamented with spinules at positions A, B, C, D, and E ( Fig. 2e ), P4 coxopodite setae not extending beyond medial margin of the basipodite ( Fig. 2f ), P5 basal segment ornamented with spinules near insertion of lateral seta.................................... C. sibiricus Lindberg, 1949

5. A1 extending beyond cephalothorax (female) and A1 first segment lacking pits, surface of the mxl palp ornamented with small spinules, mxp syncoxopodite with short membranous element lacking distal hook or club and with oblique row of long spinules, P4 coupler unornamented, P4 coxopodite ornamented with spinules at positions A, B, C, D, and occasionally F, P4 coxopodite setae extending beyond medial margin of the basipodite, P5 basal segment unornamented............ C. scutifer Sars, 1863

Figures

FIGURE 1: St. Marys River C. sibiricus female (a) A1 17-segmented (b) A1 first segment without surface pits (c) A1 segment 12 with medium length aesthetasc arrowed (d) A1 segments 15−17 with hyaline membrane arrowed.

FIGURE 2: St. Marys River C. sibiricus female (a) A2 basipodite caudal surface ornamentation at position A, B, C (b) Mxl palp proximalmost seta without long setules and surface bear (c) Mxp syncoxopodite with long distally clubbed membranous element arrowed (d) P1 basipodite ornamented with row of spinules arrowed and medial spine with bare proximal margin arrowed (e) P4 coxopodite ornamented with spinules at positions A, B, C, D, and E (f) P4 coxopodite setae arrowed, not extending beyond medial margin of basipodite.

FIGURE 3: Lake Erie C. divergens female (a) A1 17-segmented (b) A1 first segment with dense pitting arrowed (c) A1 segment 12 with medium length aesthetasc arrowed (d) A1 segments 15−17 with hyaline membrane arrowed.

FIGURE 4: Lake Erie C. divergens female (a) A2 basipodite caudal surface ornamentation at position A, B, C (b) Mxp syncoxopodite with short distally hooked membranous element arrowed (c) P1 basipodite ornamented with row of spinules arrowed and medial spine with heteronomous setulation arrowed (d) P4 coxopodite ornamentation with spinules at positions A, C, D, and E (e) P4 coxopodite setae arrowed, extending beyond medial margin of basipodite

FIGURE 5: Lake Erie C. divergens male (a) A1 geniculate (b) Mxl palp proximalmost seta ornamented with long setules (arrowed) and large spinules on surface arrowed (c) P4 coupler ornamented with horizontal row of long hairs (arrowed).