Cryptopontius, Giesbrecht, 1899

Farias, Amilcar, Neves, Elizabeth G. & Johnsson, Rodrigo, 2020, Two new species of Cryptopontius Giesbrecht, 1899 (Copepoda, Siphonostomatoida Artotrogidae) associated with invertebrates from Northeastern Brazil, Zootaxa 4810 (3), pp. 481-494 : 492-493

Key to the species of the genus Cryptopontius

1. Endopod of leg 4 reduced to a single segment ….......................................... C. digitatus Kim, 1996

- Endopod of leg 4 absent …............................................................................. 2

2(1). Antennule with 7 segments proximal to fused ancestral segments IX–XII, with ancestral segments III–IV fused …............................................................................ C. aesthetascus Neves & Johnsson, 2008

- Antennule with less than 7 segments proximal to fused ancestral segments IX–XII ….............................. 3

3(2). Antennule with 5 segments proximal to fused ancestral segments IX–XII, with ancestral segments III–VI fused ….......................................................................................... C. pentadikos sp. nov.

- Antennule with less than 5 segments proximal to fused ancestral segments IX–XII...............................… 4

4(3). Female antennule 8-segmented …........................................................................ 5

- Female antennule with more than 8-segmented ….......................................................... 11

5(4). Caudal rami longer than anal somite ….................................................................... 6

- Caudal rami shorter than anal somite ….................................................. C. ricinius Malt, 1991

6(5). Second endopodal segment of leg 1 armed with one or two setae …............................................. 7

- Second endopodal segment of leg 1 unarmed …......................................... C. ignotus (Brady, 1910)

7(6). Second endopodal segment of leg 1 with single seta …....................................................... 8

- Second endopodal segment of leg 1 with two setae …........................................................ 9

8(7). Antennal exopod with single seta …..................................................... C. latus (Brady, 1910)

- Antennal exopod with two setae …...................................................... C. minor Stock, 1965

9(7). Third exopodal segment of leg 1 with eight elements......................................................… 10

- Third exopodal segment of leg 1 with seven elements …................................. C. quinquesetus Kim, 1996

10(9). Third endopodal segment of leg 1 with six setae and three setae on the free segment of leg 5................................................................................................ C. expletus Neves & Johnsson, 2008

- Third endopodal segment of leg 1 with five setae and two setae on the free segment of leg 5 ….. C. donghaensis Kim, 1996

11(4) Female antennule 9-segmented …....................................................................... 12

- Female antennule 10-segmented …..................................................................... 24

12 (5). Third exopodal segment of leg 4 with eight elements …...................................................... 13

- Third exopodal segment of leg 4 with nine elements...................................................... …14

13 (12) Free segment of female leg 5 longer than wide, male antennule 9-segmented …............... C. longipes Nicholls, 1944

- Free segment of female leg 5 wider than long, male antennule 10-segmented....................... C. acutus Kim 2007

14(12). Second endopodal segment of leg 1 with two setae …....................................................... 15

- Second endopodal segment of leg 1 with one seta …........................................................ 21

15(14). Maxillule outer lobe with three setae …........................................ C. brevifurcatus ( Giesbrecht, 1895)

- Maxillule outer lobe with two setae …................................................................... 16

16(15). Maxillule inner lobe with one seta …............................................. C. paracapitalis Nicholls, 1944

- Maxillule inner lobe with more than one seta …............................................................ 17

17(16). Maxillule inner lobe with two setae …................................................................... 18

- Maxillule inner lobe with three setae ….................................................................. 20

18(17). Maxillule inner lobe with two setae and similar in length to outer lobe …........................................ 19

- Maxillule inner lobe with two setae and longer than outer lobe ….......... C. tanacredii Johnsson, Rocha & Boyko, 2002

19(18). Antennal exopod bearing a single terminal seta …................................ C. gracilioides Ummerkutty, 1961

- Antennal exopod bearing two terminal setae …......................................... C. phyllogorgius sp. nov.

20(17). Maxillule inner lobe with three setae and much longer than outer lobe …................. C. brevicaudatus (Brady, 1910)

- Maxillule inner lobe with three setae and similar in length to outer lobe …............... C. madeirensis Johnsson, 2001

21(14). Third exopodal segment of leg 1 with eight elements (III+5) …............................ C. proximus Nicholls, 1944

- Third exopodal segment of leg 1 with seven elements (III+4) …............................................... 22

22(21). Third endopodal segment of leg 1 with five setae …....................................... C. gracilis Wilson, 1932

- Third endopodal segment of leg 1 with six setae …......................................................... 23

23(22). Third exopodal segment of leg 2 with III-6; third endopodal segment of leg 2 with 1-5...... … C. tenuis ( Giesbrecht, 1895)

- Third exopodal segment of leg 2 with IV-5; third endopodal segment of leg 2 with 1-1+I-3 …................................................................................................... C. orientalis Ummerkutty, 1961

24(11). Third exopodal segment of leg 1 with eight elements (III-5) …................................................ 25

- Third exopodal segment of leg 1 with seven elements (III-4) …............................................... 26

25(24). Maxillule outer lobe with three setae; antennal exopod with two setae …........................ C. ascidius Kim, 1996

- Maxillule outer lobe with two setae; antennal exopod with one seta …........................ C. similis Nicholls, 1944

26(24). Siphon reaching between insertion of maxilla and maxilliped …........................ C. capitalis ( Giesbrecht, 1895)

- Siphon reaching insertion of leg 1 …............................................... C. thorelli ( Giesbrecht, 1895)