Canthocamptus, Westwood, 1836

Novikov, Aleksandr & Sharafutdinova, Dayana, 2022, Revision of the genus Canthocamptus (Copepoda: Harpacticoida) with a description of a new species from the Lena River Delta (North-eastern Siberia), European Journal of Taxonomy 826 (1), pp. 33-63 : 57-58

Key to the species of Canthocamptus for males (female characters indicated by asterisk)

1. Mandibular palp with 3 setae ..................................................................... C. kunzi Apostolov, 1969

– Mandibular palp with 5 setae............................................................................................................ 2

2. P4 Enp2 with normal outer spine ...................................................................................................... 3

– P4 Enp2 with modified finger-like outer spine ................................................................................. 6

3. Habitus wide; P1 Enp1 reaching end of Exp2; anal somite with ventral processes ......................... 4

– Habitus sub-cylindrical; P1 Enp1 reaching middle of Exp3; anal somite without ventral processes ........................................................................................................................................................... 5

4. P5 eXopod with 6 setae; *caudal rami seta V of female conical ......................................................... ..................................................................................................... C. verestschagini ( Borutzky, 1931)

– P5 eXopod with 5 setae; *caudal rami seta V of female long, normal ................................................ ......................................................................................................... C. longifurcatus Borutzky, 1947

5. *Caudal rami seta IV of female normal ........................................................ C. latus Borutzky, 1947

– *Caudal rami seta IV of female sickle-like, with bulb ............................ C. bulbifer Borutzky, 1947

6. Anal somite with unguiform processes ............................................................................................. 7

– Anal somite without processes ....................................................................................................... 12

7. P3 Enp3 with 2 normal setae ............................................................................................................ 8

– P3 Enp3 with vestigial or without setae ........................................................................................... 9

8. Caudal rami setae IV and V with ʻhelle Stelleʼ ........................... C. oregonensis M.S. Wilson, 1956

– Caudal rami setae IV and V without ʻhelle Stelleʼ .............................. C. staphylinus (Jurine, 1820)

9. P4 Enp2 with 2 normal inner setae ................................................................................................. 10

– P4 Enp2 with 2 vestigial or without inner setae ..............................................................................11

10. Caudal rami without inner spinules; *P5 eXopod of female without inner spinules .......................... ................................................................................................ C. microstaphylinus s. str. Wolf, 1905

– Caudal rami with inner spinules; *P5 eXopod of female with inner spinules .................................... ............................................................................................ C. microstaphylinus monardi Roy, 1927

11. Distal edge of caudal rami with spinules ............. C. macrosetifer Ishida in Ishida & Kikuchi, 1999

– Distal edge of caudal rami without spinules ........ C. takkobuensis Ishida in Ishida & Kikuchi, 1999

12. P2 Enp2 with 5 setae ....................................................................................................................... 13

– P2 Enp2 with 4 setae ....................................................................................................................... 19

13. P3 Enp3 with vestigial seta ............................................................................................................. 14

– P3 Enp3 with 2 normal setae .......................................................................................................... 15

14. Caudal rami with inner spinules; *P3 Enp3 of females with 5 setae .................................................. .............................................................................. C. kitaurensis Kikuchi in Ishida & Kikuchi, 1999

– Caudal rami without inner spinules; *P3 Enp3 of females with 4 setae ............................................ ......................................................................................................... C. carinatus Shen & Sung, 1973

15. P5 endopod inner seta/outer seta length>5 .................................................... C. sinuus Coker, 1934

– P5 endopod inner seta/outer seta length <5 .................................................................................... 16

16. Anal operculum naked ........................................................................... C. glacialis Lilljeborg, 1902

– Anal operculum spinulose .............................................................................................................. 17

17. Caudal rami short (length to width ratio = 2) ..................................... C. baikalensis Borutzky, 1931

– Caudal rami long (length to width ratio = 2.5) ............................................................................... 18

18. Caudal rami seta V with ʻhelle Stelleʼ ...................................................... C. iaponicus Brehm, 1927

– Caudal rami seta V without ʻhelle Stelleʼ .......................................... C. staphylinoides Pearse, 1905

19. Caudal rami very long (length to width ratio>3.5) .................... C. robertcokeri M.S. Wilson, 1958

– Caudal rami of normal length (length to width ratio <3) ................................................................ 20

20. Caudal rami with inner spinules; *P5 eXopod of females with inner spinules ................................... ......................................................................................................................... C. sinuus Coker, 1934

– Caudal rami without inner spinules; *P5 eXopod of females without inner spinules ..................... 21

21. Spinular row of penultimate somite with gap; *caudal rami seta V of female without bulb ............. ...................................................................................................................... C. assimilis Kiefer, 1931

– Penultimate somite with circumsomitic spinular row; *caudal rami seta V of female with bulb ....... .......................................................................................................... C. waldemarschneideri sp. nov.