Diastylopsis

Gerken, Sarah, 2015, New Zealand Diastylidae and Gynodiastylidae (Crustacea: Cumacea), Zootaxa 4031 (1), pp. 1-77 : 42

Key to all species of Diastylopsis

1. Carapace smooth, unornamented except for ridge on pseudorostral lobe........................................... 2

- Carapace with multiple ridges, sculpturing or spines.......................................................... 4

2. Telson longer than uropod peduncles........................................................ D. incompta n. sp.

- Telson shorter than uropod peduncles...................................................................... 3

3. Uropod endopod shorter than exopod.............................................................. D. crassior

- Uropod endopod longer than exopod............................................................. D. elongata

4. Carapace without ridges, anterior half with spines, increasing in length anteriorly........................ D. senta n. sp.

- Carapace with ridges, with or without spines................................................................ 5

5. Telson longer or equal to uropod peduncles................................................................. 6

- Telson shorter than uropod peduncles..................................................................... 11

6. Maxilliped 3 basis greatly expanded, opercular; carapace with ridges only on anterior 1/3................... D. thilenuisi

- Maxilliped 3 basis not greatly expanded, not opercular; carapace with ridges on at least anterior ½, may be throughout..... 7

7. Telson with 3 terminal setae..................................................................... D. trisetosa

- Telson with 2 terminal setae............................................................................. 8

8. Carapace with multiple concentric lateral ridges............................................................. 9

- Carapace with 2–3 parallel ridges........................................................................ 10

9. Telson post-anal portion longer or equal to pre-anal portion; carapace sculpturing weak........................ D. goeki

- Telson post-anal portion shorter than pre-anal portion; carapace very strongly sculptured.................... D. annulata

10. Telson subequal to uropod peduncles; pereopod 1 elongate, carpus propodus dactylus together much longer than basis ischium merus together........................................................................... D. bicarina n.sp.

- Telson longer than uropod peduncles; pereopod 1 not elongate, carpus propodus dactylus together much shorter than basis ischium merus together.................................................................. D. aspratilis n. sp.

11. Telson more than half length of uropod peduncles...................................................... D. tenuis

- Telson less than half length of uropod peduncles..................................................... D. dawsoni