Key to species of Sophrosyne

1. Epimeron 3, posteroventral corner rounded............................................................................................................... 2

- Epimeron 3, posteroventral corner angled.................................................................................................................. 7

2. Telson entire .......................................................................................................................................... S. integricauda

- Telson cleft.................................................................................................................................................................. 3

3. Gnathopod 2 palm large................................................................................................................................ S. peartae

- Gnathopod 2 palm small............................................................................................................................................. 4

4. Mandibular palp article 2 with D2-setae..................................................................................................................... 5

- Mandibular palp article 2 without D2-setae............................................................................................................... 6

5. Mandibular palp article 3 with D3-setae; uropod 2 without robust setae on rami.................................. S. californica

- Mandibular palp article 3 without D3-setae; uropod 2 with robust setae on at least one ramus.............. S. cantractia

6. Gnathopod 2 palm convex; pereopod 6 coxa slightly lobate posteriorly................................................. S. robertsoni

- Gnathopod 2 palm concave; pereopod 6 coxa not lobate posteriorly....................................................... S. antarctica

7. Gnathopod 2 palm large............................................................................................................................... S. murrayi

- Gnathopod 2 palm small............................................................................................................................................. 8

8. Pereopod 7, basis posteroventral lobe extending beyond ischium............................................................................. 9

- Pereopod 7, basis posteroventral lobe not extending beyond ischium..................................................................... 10

9. Maxilliped palp article 2 broad; pereopod 6 coxa strongly lobate posteriorly............................................ S. hispana

- Maxilliped palp article 2 slender; pereopod 6 coxa slightly lobate posteriorly........................................... S. rodondo

10. Pereopod 6 coxa strongly lobate posteriorly............................................................................................................. 11

- Pereopod 6 coxa slightly lobate posteriorly.............................................................................................................. 13

11. Mandible palp article 2 broadened distally.................................................................................................. S. ledoyeri

- Mandible palp article 2 slender................................................................................................................................. 12

12. Mandible palp articles 2 and 3 with D-setae; telson longer than broad.................................................... S. inverarae

- Mandible palp articles 2 and 3 without D-setae; telson about as long as broad.............................................. S. ruffoi

13. Maxilliped palp article 2 slender (length about 2.4 x breadth); telson moderately cleft (about 38%).......... S. moorei

- Maxilliped palp article 2 broad (length about 1.8 x breadth); telson deeply cleft (about 67%)..................... S. abyssi