Key to Leucothoe species from Brazil (according to updated checklist by Serejo & Siqueira, 2018)

1. Gnathopod 2, coxa 2 with truncated corners.................................... L. kensleyi Thomas & Klebba, 2006

- Gnathopod 2, coxa 2 with rounded corners................................................................. 2

2. Gnathopod 2, anteriorly excavated and projected to dactylus......................... L. laurensi Thomas & Ortiz, 1995

- Gnathopod 2, anteriorly convex and not projected to dactylus.................................................. 3

3. Mandibular palp article 3 reduced (smaller or subequal in length to article 1)...................................... 4

- Mandibular palp article 3 well developed (notably longer than article 1)…........................................ 7

4. Pereopod 7 basis globose (about 20% longer than large) with posterior margin subtriangular…........................ 5

- Pereopod 7 basis thin (about 40% longer than large) with posterior margin rounded…............................... 6

5. Gnathopod 1 dactylus short, reaching 10% of propodus length…............................ L. lihue J.L. Barnard, 1970

- Gnathopod 1 dactylus long, reaching more than 50% of propodus length…................... L. occidentalis Reid, 1951

6. Coxa 3-4 crenulate on distal margin…................................................... L. leptosa Serejo, 1998

- Coxa 3-4 smooth on distal margin….................................................. L. urospinosa Serejo, 1998

7. Gnathopod 1 (males) dactylus longer than basis with strong subtriangular processes…........ L. cheirisierra Serejo, 1998

- Gnathopod 1 (males) dactylus as long or smaller than basis, without strong subrtriangular processes….................. 8

8. Gnathopod 2 (males) basis anteroventral corner projected, propodus two times longer than large …................................................................................................... L. basilobata Serejo, 1998

- Gnathopod 2 (males) basis anteroventral corner not projected, propodus three times longer than large….. L. oxumae sp. nov.