Key to East Asian Loxoconcha and Loxocorniculum species with described soft parts

(Modified after Okubo, 1980)

1. Valves reticulated ··················································· 2

- Valves pitted ························································· 12

2. Greatest height situated behind the middle ············ 3

- Greatest height situated medially or in front of the middle ····································································· 5

3. Distal lobe of the hemipenis in the shape of an equilateral triangle ····································· L. lilljeborgii

- Distal lobe of the hemipenis not in the shape of equilateral triangle, but with elongated ventral margin ··· ··············································································· 4

4. Tip of the distal lobe filamentous ···· L. shanhaiensis

- Tip of the distal lobe pointed ·················· L. japonica

5. Valve with ventral wing­like ridge ventrally ············· ··························································· L. harimensis

- Valve without ventral wing­like ridge ventrally ····· 6

6. Dorsal margin of the valves almost straight in lateral view, especially in males ········································ 7

- Dorsal margin rather sinusoid ·············· L. bizenensis

7. In males height to length ration of the shell does not exceed 50% ···························································· 8

- In males height to length ratio of the shell over 60% ······························································ L. tosaensis

8. Terminal segment of mandibular palp with four setae/ claws ······································································· 9

- Terminal segment of mandibular palp with 5 setae (one small and plumose, 4 longer and simple) ·················· ································································· L. kosugii

9. Terminal segment of mandibular palp with four simple setae ································································ 10

- Terminal segment of mandibular palp with two claws and 2 setae ···································· L. uranouchiensis

10. Tip of the distal lobe of hemipenis rounded ········· 11

- Tip of the distal lobe ending with thin, elongated, finger­like projection ····························· L. sesokoensis

11. Third thoracopod much larger and longer than first and second thoracopod ····························· L. santosi

- Third thoracopod not much larger and longer than first and second thoracopod ····················· L. noharai

12. Valve without lateral ridges ······················ L. pulchra

- Valves with three posterior and two anterior ridges ·· ····································· Loxocorniculum mutsuense