Key to the species of Sinocorophium (modified from Kim, 2012)

1. Antenna 2 sexually dimorphic; gnathopod 1, palm steeply oblique to transverse; pereopods 3–4, merus subequal to carpus.......................................................................................................2

- Antenna 2 sexually subsimilar; gnathopod 1, palm gently convex; pereopods 3–4, merus longer than carpus............. 5

2. Body medium sized, more than 5 mm; mandibular palp, terminal article short, much shorter than proximal article.........3

- Body small sized, less than 5 mm; mandibular palp, terminal article normal, subequal to proximal article................4

3. Antenna 2 (♀), peduncular article 4 with 2 ventral spines; gnathopod 2 (♂), basis with dentiform process anterodistally...................................................................................... S. sinense (Zhang, 1974)

- Antenna 2 (♀), peduncular article 4 without ventral spine; gnathopod 2 (♂), basis straight, without dentiform process antero- distally........................................................................ S. heteroceratum (Yu, 1938)

4. Rostrum minute, vestigial...................................................... S. lamellatum (Hirayama, 1984)

- Rostrum rather prominent............................................................ S. minutum (Dang, 1965)

5. Rostrum short, vestigial; uropod 1, rami subequal in length............................ S. japonicum (Hirayama, 1984)

- Rostrum elongate; uropod 1, inner ramus shorter than outer....................................................6

6. Antenna 2, peduncular article 4 with 2 ventrodistal large teeth..................................................7

- Antenna 2, peduncular article 4 with 1 ventrodistal large tooth..................................................8

7. Antenna 2 (♂), peduncular article 4 without rows of teeth medially......................... S. homoceratum (Yu, 1938)

- Antenna 2 (♂♀), peduncular article 4 with two rows of teeth medially................. S. dongtanense (Ren & Liu, 2014)

8. Antenna 2, peduncular article 4 stubby, more than 0.5 × as wide as long.................... S. intermedium (Dang, 1965)

- Antenna 2, peduncular article 4 elongate, less than 0.5 × as wide as long..........................................9

9. Body large sized, more than 10 mm; uropod 1, lateral margin of peduncle with setae; uropod 3, ramus longer than peduncle................................................................................ S. hangangense (Kim, 2012)

- Body small sized, less than 7 mm; uropod 1, lateral margin of peduncle with spines; uropod 3, ramus subequal or shorter than peduncle...........................................................................................10

10. Antenna 1, peduncular article 1 subequal in length to article 2........................... S. alienense (Chapman, 1988)

- Antenna 1, peduncular article 1 longer than article 2......................................................... 11

11. Uropod 3, ramus semi-circular, shorter than peduncle........................... S. triangulopedarum (Hirayama, 1990)

- Uropod 3, ramus ovate, subequal to peduncle..............................................................12

12. Rostrum pointed distally; uropod 1, inner ramus much shorter than outer.................... S. monospinum (Shen, 1955)

- Rostrum subpointed distally; uropod 1, inner ramus slightly shorter than outer..................... S. jindoense sp. nov.