Key to species of Genus Sorex in Korea

1 Total length> 120 mm, hind foot> 16 mm .......................................................... S. mirabilis

- Total length <120 mm, hind foot <15 mm .................................................................. 2

2 Heavily pigmented teeth (red pigment reaching into bases of molariform teeth)......................... S. daphaenodon

- Red pigment not extending into bases of molariform.......................................................... 3

3 Rostrum narrow and slender (nasal bone ratio to least interorbital breath 2); 1 st to 3 rd upper unicuspids teeth similar size; 4 th and 5 th unicuspids much smaller................................................................... S. gracillimus

- Rostrum not narrow (nasal bone ratio to least interorbital breath <2); 1 st to 3 rd upper unicuspids teeth not similar size....... 4

4 Second upper unicuspid tooth smaller than 1 st and 3 rd unicuspids..................................... S. minutissimus

- Second upper unicuspid tooth same or larger than 3 rd unicuspid................................................. 5

5 Head and body> 70 mm; upper unicuspids size evenly decrease from 1 st to 5 th; ventral pelage color almost as dark as dorsal color.......................................................................................... S. isodon

- Head and body <60 mm; 1–4 upper unicuspids in similar size (1 st & 2 nd in same size; 3 rd & 4 th in same but slightly smaller than 1 st & 2 nd pair; 5 th is noticeably small); pelage dorsal color much darker than ventral color................... S. caecutiens