Asterocheres, Boeck, 1859

Lee, Il-Hoi Kim and Taekjun, 2024, Copepods of the genus Asterocheres Boeck, 1859 (Siphonostomatoida: Asterocheridae) from Korean waters, Journal of Species Research 13 (2), pp. 185-254 : 251-252

Key to species of Asterocheres of Korean waters

(based on females)

1. Caudal ramus twice longer than wide; mandibular palp about 1.9 times longer than mandibular stylet ····· ·············································· A. lilljebogi Boeck, 1859

- Caudal ramus distinctly less than twice as long as wide; mandibular palp at most 1.5 times longer than mandibular stylet······························································· 2

2. Caudal ramus 1.3 to 1.6 times longer than wide········ 3

- Caudal ramus distinctly less than 1.3 times as long as wide············································································ 5

3. Antennule 19-segmented; leg 3 lacking inner coxal seta························································ A. zodius n. sp.

- Antennule 21-segmented; leg 3 with inner coxal seta ··· ···················································································· 4

4. Mandibular palp 2-segmented; oral siphon reaching insertion of leg 1; exopodal segment of fifth leg about 3 times longer than wide ······················ A. culicis n. sp.

- Mandibular palp 1-segmented; oral siphon reaching insertion of maxilliped; exopodal segment of fifth leg 1.85 times longer than wide ········· A. spiniventer n. sp.

5. Oral siphon flexible, extending over leg 4 ··················· ···································· A. siphonatus Giesbrecht, 1897

- Oral siphon straight, not flexible, extending before leg 2·················································································· 6

6. Antennule 19-segmented, with aesthetasc on second segment from the distal ·························· A. exilis n. sp.

- Antennule 20- or 21-segmented, with aesthetasc on third or fourth segment from the distal ······················ 7

7. Leg 1 lacking inner coxal seta ··································· 8

- Leg 1 bearing inner coxal seta ··································· 9

8. Third endopodal segment of leg 1 bearing elongated distal process; mandibular palp plus longer distal seta shorter than stylet···························· A. processus n. sp.

- Third endopodal segment of leg 1 lacking elongated distal process; mandibular palp plus longer distal seta as long as stylet ···························································· ························ A. banderaae Kim I.H. & Lee T., 2023

9. Caudal ramus with 6 setae and 1 large, attenuated aesthetasc; mandibular palp plus longer distal seta distinctly shorter than stylet; exopodal segment of female leg 5 about 4.5 times longer than wide ··············· ·············································· A. quadridens Kim, 2016

- Caudal ramus with 6 setae only; mandibular palp plus longer distal seta longer or as long as stylet; exopodal segment of female leg 5 less than 4 times as long as wide ··························································· 10

10. Antennule 20-segmented, with aesthetasc on third segment from the distal ·········································· 11

- Antennule 21-segmented, with aesthetasc on fourth segment from the distal ·········································· 15

11. Mandibular palp 2-segmented································ 12

- Mandibular palp 1-segmented································ 13

12. Postgenital lateral margin of genital double-somite with about 15 setules; mandibular stylet with 8 teeth at distal region···························· A. cuspis Kim, 2016

- Postgenital lateral margin of genital double-somite with 4-7 setules; mandibular stylet with 3 teeth at distal region······································ A. tridentatus n. sp.

13. Leg 4 lacking inner coxal seta; genital double-somite distinctly longer than wide, with 12 spinules on postgenital lateral margin ················ A. eurychelatus n. sp.

- Leg 4 with small inner coxal seta; genital double-somite shorter than or as long as wide, with 6-9 spinules on postgenital lateral margin ··································· 14

14. Terminal claw of antenna slightly longer than first endopodal segment; mandibular stylet with 6 teeth at distal region; all setae on female leg 5 naked·············· ····················································· A. scutellatus n. sp.

- Terminal claw of antenna shorter than first endopodal segment; mandibular stylet with 6 teeth at distal region; outer and middle setae on exopod of female leg 5 pinnate ······························ A. tetraodontis n. sp.

15. Mandibular palp 1-segmented································ 16

- Mandibular palp 2-segmented································ 18

16. Terminal claw of antenna about 1.3 times longer than first endopodal segment; postgenital lateral margin of genital double-somite with about 25 setules················ ································································· A. fici n. sp.

- Terminal claw of antenna slightly longer or shorter than first endopodal segment; postgenital lateral margin of genital double-somite with less than 20 setules ····· 17

17. Fourth pedigerous somite (fourth prosomal somite) with serrate lateral margins; outer and middle setae on exopod of leg 5 more than 1.5 times as long as exopodal segment···························· A. serratus n. sp.

- Fourth pedigerous somite with smooth lateral margins; outer and middle setae on exopod of leg 5 less than 1.3 times as long as exopodal segment ·············· ······················································ A. nodulosus n. sp.

18. Caudal ramus 1.15 times longer than wide; oral siphon extending to insertion of leg 1; 3 inner distal setae on inner lobe of maxillule more than twice as long as inner lobe; exopodal segment of leg 5 covered with spinules all over ····· A. horridus Kim, 2016

- Caudal ramus shorter than or as long as wide; oral siphon extending before insertion of leg 1; 3 inner distal seta on inner lobe of maxillule less than twice as long as inner lobe; exopodal segment of leg 5 with spinules only on inner and outer margins ······ 19

19. Postgenital lateral margin of genital double-somite with about 30 setules; middle seta on exopod of leg 5 longer than other 2 setae ········································· ········································ A. simulans (Scott T., 1898)

- Postgenital lateral margin of genital double-somite with at most 20 setules; middle seta on exopod of leg 5 shorter or as long as outer seta ······················ 20

20. Terminal claw of antenna 1.6 times longer than first endopodal segment······················· A. dokdoicus n. sp.

- Terminal claw of antenna at most 1.1 times longer than first endopodal segment·································· 21

21. Mandibular palp about 1.4 times longer than stylet; outer seta on exopod of leg 5 longer than middle seta; postgenital lateral margin of genital double-somite with 12 thin, longer anterior spinules and 4 or 5 thicker but shorter spinules ····· A. aesthetes Ho, 1984

- Mandibular palp as long as stylet; outer seta on exopod of leg 5 as long as middle seta; postgenital lateral margin of genital double-somite with about 20 equally thin spinules······················· A. geminus n. sp.