Stylicletodes Lang, 1936

Ma, Lin, Liu, Qing He, Li, Xin Zheng & Huys, Rony, 2021, A new species of Stylicletodes Lang, 1936 (Copepoda: Harpacticoida: Cletodidae) from the East China Sea, including an updated key to species and synopsis of distribution records, Zootaxa 5051 (1), pp. 423-442 : 436

Key to species of Stylicletodes Lang, 1936

Both the latest dichotomous key by Bodin (1968) and the tabular key by Wells (2007) have been superseded. A new key to the seven valid species is presented below and rectifies oversights and misinterpretations contained in previous keys. Gómez (2000) pointed out the close similarity between S. stylicaudatus and S. oligochaeta ; comparison between these species is necessarily based on the male of the former and the female of the latter and restricted to caudal ramus morphology.

1. Anal operculum terminating in conspicuous, median, setular extension; armature elements on P 5 ♀ densely plumose...... 2

- Anal operculum rounded, without median, setular extension; armature elements on P 5 ♀ naked or sparsely pinnate........ 4

2. P1 enp-2 with one seta; P3 exp-3 with five setae/spines..................................... S. minutus Bodin, 1968

- P1 enp-2 with two setae; P3 exp-3 with six setae/spines....................................................... 3

3. P4 exp-3 with five setae/spines; P4 enp-2 with one seta........................................... S. wellsi sp. nov.

- P4 exp-3 with six setae/spines; P4 enp-2 with two setae..................................... S. reductus Wells, 1965

4. P3–P4 exp-3 with five setae/spines....................................................................... 5

- P3–P4 exp-3 with six setae/spines........................................................................ 6

5. Caudal ramus extremely long and narrow, about half as long as length of body somites combined, divergent; seta VII originating from middle third of ramus..................................................... S. oligochaeta Bodin, 1968

- Caudal ramus distinctly shorter and wider; seta VII originating from proximal third......... S. stylicaudatus ( Willey, 1935)

6. Caudal ramus maximum length:width ratio 7–11, about as long as urosome; inner margin virtually straight, with long setules in proximal half; seta II reaching to about halfway ramus length; setae I–II arising from small outer margin protuberance................................................................................. S. longicaudatus ( Brady, 1880)

- Caudal ramus maximum length:width ratio 4–5, about 60% of urosome length; inner margin convex in proximal half, without setular ornamentation; seta II reaching to posterior margin of ramus; setae I–II arising from conspicuous outer margin protuberance............................................................................. S. verisimilis Lang, 1965