Key to species of Adult Male Talorchestia

1. Gnathopod 2 palm with rounded protuberance (large or slight) near dactylar hinge.................................. 2

- Gnathopod 2 palm without rounded protuberance near dactylar hinge............................................ 6

2. Gnathopod 2 palm reaching at least 75% along posterior margin of propodus...................................... 3

- Gnathopod 2 palm reaching less than 75% along posterior margin of propodus..................................... 4

3. Gnathopod 1 carpus about 2.5 × as long as broad. Gnathopod 2 palm moderately covered in robust setae (9+3). Uropod 3 ramus subequal in length to peduncle................................................................... T. bunaken

- Gnathopod 1 carpus about 3 × as long as broad. Gnathopod 2 palm strongly covered in robust setae (12+7). Uropod 3 ramus shorter in length than peduncle.................................................................... T. yoyoae

4. Gnathopod 2 carpus/propodus fused; gnathopod 2 dactylus longer than palm............................ T. spinipalma

- Gnathopod 2 carpus/propodus not fused; gnathopod 2 dactylus subequal in length to palm........................... 5

5. Gnathopod 1 carpus about 2.5 × as long as wide. Uropod 3 ramus about 2.4 × as long as broad with about 3–5 marginal setae. Telson with about 10 robust setae per lobe....................................................... T. mindorensis

- Gnathopod 1 carpus about 3.3 × as long as wide. Uropod 3 ramus about 3 × as long as broad with about 7 marginal setae. Telson with about 13 robust setae per lobe........................................................... T. terraereginae

6. Epimeron 3 posteroventral corner with large subacute tooth.................................................... 7

- Epimeron 3 posteroventral corner with small subacute tooth or subquadrate...................................... 13

7. Gnathopod 2 propodus palm without sinus; palm reaching more than halfway along posterior margin................... 8

- Gnathopod 2 propodus palm with small sinus near dactylar hinge; palm reaching less than halfway along posterior margin..................................................................................................... 12

8. Gnathopod 2 dactylus subequal in length to palm............................................................ 9

- Gnathopod 2 dactylus longer than palm................................................................... 10

9. Uropod 3 ramus not fused to peduncle. Telson with 8–9 robust setae..................................... T. martensii

- Uropod 3 ramus partially fused to peduncle. Telson with 10–11 robust setae................................. T. qeshm

10. Antenna 2 longer than body...................................................................... T. gracilis

- Antenna 2 more than half but not exceeding body length..................................................... 11

11. Gnathopod 2 propodus without distal protuberance................................................... T. dampieri

- Gnathopod 2 propodus with distal protuberance....................................................... T. affinis

12. Uropod 1 endopod with marginal setae in one row......................................... T. sp. (of Chilton, 1921)

- Uropod 1 endopod with marginal setae in two rows................................................... T. anakao

13. Telson with 6 or less robust setae................................................................... T. brucei

- Telson with more than 7 robust setae..................................................................... 14

14. Gnathopod 2 dactylus with shallow posteroproximal sinus and small protuberance.............................. T. dili

- Gnathopod 2 dactylus with shallow posteroproximal sinus, without protuberance.................................. 15

15. Gnathopod 1 carpus about 1.5 x as long as propodus. Telson with at least 10 robust setae..................... T. morinoi

- Gnathopod 1 carpus about twice as long as propodus. Telson with less than 7–9 robust setae......................... 16

16. Gnathopod 1 propodus 3 × as long as broad. Gnathopod 2 palm extending about 56% along posterior margin of propodus............................................................................................... T. seringat

- Gnathopod 1 propodus 2.2 × as long as broad. Gnathopod 2 palm extending about 52% along posterior margin of propodus.............................................................................................. T. sipadan