Conchoecia

Chavtur, Vladimir G. & Bashmanov, Alexander G., 2018, Pelagic ostracods of the new subtribe Conchoeciina (Ostracoda, Crustacea) from the North Pacific, Zootaxa 4516 (1), pp. 1-127 : 48-49

Key to species of genus Conchoecia

Adult males:

1 Right clasping organ is acutely-angled; epipodite of the mandible has a rudimentary seta............. C. subarcuata Claus.

- Right clasping organ almost is squared-angled; epipodite of the mandible has relatively developed seta................. 2.

2 Carapace length is> 2.1 mm; armature of seta-e on the first antenna has10–12 distal pairs of spines, and 12 –16 alternating spines directed proximally; lengths of these paired spines are noticeably more than the diameter of the comb seta-e; masticatory pad of the mandible has six flat spines......................................... C. rudyakovi Chavtur , sp. nov.

- Carapace length is <2.1 mm (2.1 mm only for C. magna in Poulsen 1973 and C. tetragona in Vavra 1906 ); armature of seta-e on the first antenna has 12–16 distal pairs of spines, and 13–20 alternating spines directed proximally; length of these paired spines are subequal or somewhat shorter than the diameter of the comb seta-e; masticatory pad of the mandible has four flat spines.............................................................................................. 3.

3 Armature of seta-e on the first antenna has 12–16 distal pairs of spines and 13–20 alternating spines directed proximally; setab has no pad......................................................................................... 4.

- Armature of seta-e on the first antenna has 42–45 paired spines, seta-b has a short pad....... C. aff. magna (sensu Martens) .

4 Carapace has conspicuous concentric striation; capitulum of the frontal organ is broad; spines on seta-e of the first antenna are strongly oblique to this seta; tip of processus mamillaris on the second antenna has a rather long papilla................................................................................................ C. sculpta Chavtur , sp. nov.

- Carapace has weak concentric striation (not always noticeable); capitulum of the frontal organ is narrow or relatively narrow (broad only in C. magna in Drapun & Smith 2012 ); spines on seta-e of the first antenna are moderately oblique to this seta; tip of processus mamillaris on the second antenna has no long papilla.............................................. 5.

5 Capitulum of the frontal organ is narrow and as long as the second segment of the first antenna, height of its distal portion is about 14–15% of its length; masticatory pad has 25–30 seta-like filaments; second to fifth claws of the caudal furca are relatively short and strong; copulatory organ is very narrow, its height is less than 20% of its length.................................................................................................. C. angustipilata Chavtur , sp. nov.

- Capitulum of frontal organ moderately narrow and somewhat shorter than second segment of the first antenna, height of its distal portion is about 18–22% of its length; masticatory pad has 15 seta-like filaments; second to fifth claws of the caudal furca have usual lengths and are not strong; copulatory organ is moderately narrow, its height is more than 20% of its length.............................................................................................. C. magna Claus.