Asymmetrione, Codreanu, Codreanu & Pike, 1965

Williams, Jason D., Boyko, Christopher B. & Madad, Asma Z., 2019, Branchial parasitic isopods (Crustacea: Isopoda: Bopyridae: Pseudioninae) of hermit crabs (Crustacea: Decapoda: Diogenidae) from the western Pacific, with descriptions of a new genus and three new species, Raffles Bulletin of Zoology 67, pp. 83-118 : 86

Key to species of Asymmetrione based on males [ A. imarani

Kazmi & Khatoon, 2016, not included in the key]

1. Antennae of seven articles each .............................................2

– Antennae of five or six articles each......................................4

2. Posterolateral lobes of pleotelson short, not extending beyond anal cone......................................... A. foresti ( Bourdon, 1968)

– Posterolateral lobes of pleotelson long, extending beyond anal cone..........................................................................................3

3. Body widest across pereomeres 3 and 4 .................................. ........................ A. aequalis Pardo, Boyko & Mantelatto, 2009

– Body widest across pereomere 2 .............................................. ...................................................... A. desultor Markham, 1975

4. Antennae of five articles each; maxilliped apparently absent* .................................................................................................5

– Antennae of six articles each; maxilliped present .................8

5. All pereomeres subequal in width............................................ ................................................... A. clibanarii Markham, 1975

– Pereomeres three and four wider than others ....................... 6

6. Head separated from pereomere 1; pleotelson with elongate and tapered posterolateral lobes................................................ .................................. A. globifera An, Markham & Yu, 2010

– Head fused with pereomere 1; pleotelson with short to moderate and rounded posterolateral lobes ............................................ 7

7. Antennae extending well beyond margin of head; extensive pigmentation on pereon and pleon ........................................... .................................. A. sallyae Williams & Schuerlein, 2005

– Antennae extending short distance beyond margin of head; small pigmentation spots on pereon and pleon ........................ ............................................ A. ambodistorta Markham, 1985a

8. Posterolateral lobes of pleotelson short; eyes absent............... ........................................................ A. dardani Bourdon, 1968

– Posterolateral lobes of pleotelson long; eyes present ............9

9. Posterolateral lobes of pleotelson with inner margins contiguous........ A. shiinoi Codreanu, Codreanu & Pike, 1965

– Posterolateral lobes of pleotelson broadly separated ...........10

10. Head trapezoidal, indistinctly separated from pereomere 1 .... ........................................................ A. harmoniae new species

– Head ovate, distinctly separated from pereomere 1.............11

11. A n t e n n a e e x t e n d i n g b e y o n d l a t e r a l m a r g i n s o f a l l pereomeres............................... A. asymmetrica ( Shiino, 1933)

– Antennae not extending beyond lateral margins of any pereomeres................................ A. nossibensis Bourdon, 1976