Mongoloniscus Verhoeff, 1930

Yang, Lina & An, Jianmei, 2021, A new species of the genus Mongoloniscus Verhoeff, 1930 (Crustacea: Isopoda: Agnaridae) from China, Zootaxa 5060 (2), pp. 265-274 : 266

Key to the known species of genus Mongoloniscus Verhoeff, 1930

1 epimera of pereonites 2–7 with white extending margin............................................. M. vannamei

- epimera of pereonites 2–7 without white extending margin.................................................... 2

2 epimera of pereonites 1–7 with noduli laterales.............................................................. 3

- epimera of pereonites 1–7 without noduli laterales........................................................... 6

3 noduli laterales on pereonites 1–7 arranged in a line................................................ M. koreanus

- noduli laterales on epimera of pereonites 1–7 not arranged in a line............................................. 4

4 noduli laterales on pereonites 1, 2–4 not arranged in a line............................................ M. persicus

- noduli laterales on pereonites 1, 2–4 arranged in a line........................................................ 5

5 all pereonites posterior margin with “Wave type ”........................................... M. chevronus sp. nov.

- all pereonites posterior margin with “Straight curve”................................................. M. sinensis

6 cephalon with less-developed lateral lobes................................................................. 7

- cephalon with developed lateral lobes..................................................................... 9

7 cephalon markedly rectangular................................................................. M. ishikawai

- cephalon markedly not rectangular....................................................................... 8

8 cephalon distinctly semicircle............................................................... M. nankaiensis

- cephalon distinctly not semicircle........................................................... M. hokurikuensis

9 exopod of pleopod 1 without long hind lobe bearing a deep hollow..................................... M. amabilis

- exopod of pleopod 1 with long hind lobe bearing a deep hollow............................................... 10

10 middle of pereon and pleon with a longitudinal pattern....................................................... 11

- middle of pereon and pleon without a longitudinal pattern.................................................... 13

11 middle of pereon and pleon with a longitudinal paler pattern....................................... M. satsumaensis

- middle of pereon and pleon with a longitudinal dark pattern................................................... 12

12 cephalon with pointed lateral lobes........................................................ M. odamiyamaensis

- cephalon with rounded lateral lobes............................................................. M. oumiensis

13 both sides of pereonite tergite without paler longitudinal pattern................................... M. circacaudatus

- both sides of pereonite tergite with paler longitudinal pattern.................................................. 14

14 telson triangular with concave sides............................................................ M. katakurai

- telson triangular with linear sides........................................................................ 15

15 eyes large, almost as long as the cephalon....................................................... M. tangoensis

- eyes small, far less than the length of the cephalon......................................................... 16

16 middle of pleon without paler pattern.............................................................. M. arvus

- middle of pleon with paler pattern....................................................................... 17

17 pleon tergite 3–5 with rounded posterolateral margin............................................... M. maculatus

- pleon tergite 3–5 with pointed posterolateral margin................................................ M. masahitoi