Hemiarthrinae Markham, 1972

An, Jianmei, Chen, Ruru & Paulay, Gustav, 2020, Three new species of abdominal shrimp parasites (Crustacea: Isopoda: Bopyridae Hemiarthrinae) from the Indo-West Pacific, Zootaxa 4845 (2), pp. 264-274 : 265-266

Key to 28 genera of subfamily Hemiarthrinae Markham, 1972 (based on females)

1 Pleon without appendages.......................................................... Orophryxus Bruce, 1972a

- Pleon with appendages................................................................................. 2

2 Pleon without lateral plates............................................................................. 3

- Pleon with lateral plates................................................................................ 7

3 With sucker-like organ on the dorsum of the cephalon..................................... Neophryxus Bruce, 2007

- Without sucker-like organ on the dorsum of the cephalon...................................................... 4

4 Pereomere 1–6 with elongated, filiform coxal plates...................................... Filophryxus Bruce, 1972b

- Pereomeres without any coxal plates...................................................................... 5

5 With four pairs of biramous pleopods..................................................................... 6

- With four pairs of uniramous pleopods.............................................. Anomophryxus Shiino, 1937

6 With globose uropods............................................ Epiphrixus Nierstraz & Brender à Brandis, 1932

- Without uropods.................................................................. Hemiphryxus Bruce, 1978

7 With biramous lateral plates............................................................................. 8

- With uniramous lateral plates........................................................................... 11

8 With two pereopods on convex side of the body................................... Allodiplophryxus Markham, 1985

- With more than two pereopods on convex side of the body..................................................... 9

9 With seven pereopods on convex side of the body........................................ Cataphryxus Shiino, 1936

- With three or four pereopods on convex side of the body..................................................... 10

10 With three pereopods on convex side of the body.................................... Diplophryxus Richardson, 1904

- With four pereopods on convex side of the body..................................... Micropodiphryxus Boyko, 2012

11 Pereon with prominent coxal plates............................................... Izuohshimaphryxus Saito, 2015

- Pereon without coxal plates............................................................................ 12

12 With seven pereopods on convex side of the body........................................................... 13

- With fewer than seven pereopods on convex side of the body.................................................. 16

13 Pleon with four segments......................................... Apophrixus Nierstraz & Brender à Brandis, 1931

- Pleon with five segments.............................................................................. 14

14 With four pairs of biramous pleopods................................................... Eophrixus Caroli, 1930

- Without biramous pleopods............................................................................ 15

15 With four pairs of uniramous pleopods.............................................. Sigyn An, Boyko & Li, 2015

- With three pairs of uniramous pleopods.................................................... Loki Markham, 1972

16 With four pereopods on convex side of the body............................................................ 17

- With fewer than four pereopods on convex side of the body................................................... 19

17 With three pairs of uniramous pleopods, without uropods.................................. Mesophryxus Bruce, 1973

- With four pairs of uniramous pleopods, with uropods........................................................ 18

18. Pleon with five segments.......................................................... Eriphrixus Markham, 1990

- Pleon with four segments............................................................ Pliophrixus Caroli, 1930

19 With three pereopods on convex side of the body........................................................... 20

- With fewer than three pereopods on convex side of the body.................................................. 21

20 Second oostegite on long side arching over to dorsal surface............................ Mediophrixus Markham, 1990

- Second oostegite on long side not arching over to dorsal surface........................... Dicropleon Markham, 1972

21 With two pereopods on convex side of the body............................................................ 22

- With one pereopod on convex side of the body............................................................. 26

22 Pleon with five pleomeres............................................................................. 23

- Pleon with three pleomeres............................................................................ 25

23 With four pairs of uniramous pleopods................................................................... 24

- With four pairs of biramous pleopods............................. Hyperphrixus Nierstraz & Brender à Brandis, 1931

24 Attached dorsolaterally on host, pleomeres distinct dorsally............. Metaphrixus Nierstraz & Brender à Brandis, 1931

- Attached ventrally on host, pleomeres fused dorsally....................................... Anisarthrus Giard, 1907

25 With three pairs of uniramous pleopods, plus uropods.................................... Miophrixus Barnard, 1955

- With three pairs of biramous pleopods, without uropods................................ Anchiarthrus Markham, 1992

26 With three pairs of biramous pleopods, plus uropods............. Hypohyperphrixus Nierstraz & Brender à Brandis, 1932 - With four pairs of uniramous pleopods, without uropods..................................................... 27

27 Pleon of five segments, with lateral plates of same size........................... Hemiarthrus Giard & Bonnier, 1887

- Pleon of four segments, with lateral plates of first three pleomeres small, but very large on fourth..................................................................................................... Azygopleon Markham, 1985