Key to genera of Platorchestiinae (Adult Males)

1. Gnathopod 1 dactylus cuspidactylate...................................................................... 2

- Gnathopod 1 dactylus simplidactylate..................................................................... 3

2. Uropod 1 peduncle with distolateral robust seta absent.............................................. Platorchestia

- Uropod 1 peduncle with distolateral robust seta present............................................. Tethorchestia

3. Antenna 2 distinctly incrassate........................................................................... 4

- Antenna 2 slender or only slightly incrassate................................................................ 7

4. Uropod 1 endopod with marginal setae in one row........................................................... 5

- Uropod 1 endopod with marginal setae in two rows.......................................................... 6

5. Gnathopod 1, 2 propodus palm transverse................................................. Cocorchestia gen. nov.

- Gnathopod 1, 2 propodus palm acute......................................................... Mauritiorchestia

6. Gnathopod 2 propodus palm rounded distally or sigmoidal................................. Demaorchestia gen.nov.

- Gnathopod 2 propodus palm evenly rounded............................................. Insularorchestia gen. nov.

7. Pereopod 4 dactylus thickened proximally, with notch midway along posterior margin................................8

- Pereopod 4 dactylus not thickened proximally nor with notch on posterior margin.................................. 10

8. Pereopod 7 propodus without distal tuft of setae............................................................. 9

- Pereopod 7 propodus with distal tuft of setae..................................................... Mexorchestia

9 Uropod 1 endopod with marginal robust setae in two rows............................................ Miyamotoia

- Uropod 1 endopod with marginal robust setae in one row............................................... Chroestia

10. Gnathopod 2 dactylus blunt distally...................................................................... 11

- Gnathopod 2 dactylus attenuated or acute distally........................................................... 12

11. Gnathopod 2 propodus palm transverse......................................................... Cariborchestia

- Gnathopod 2 propodus palm acute.............................................................. Pickorchestia

12 Uropod 1 peduncle, distolateral robust seta present.......................................................... 13

- Uropod 1 peduncle, distolateral robust seta absent.......................................................... 14

13. Pereopod 6 incrassate......................................................................... Vallorchestia

- Pereopod 6 not incrassate.................................................................... Yamatorchestia

14 Telson rounded distally, maxillipedal palp slender................................................ Laniporchestia

- Telson tapering distally, maxillipedal palp broad....................................................... Morinoia