1. Pereopods 3 & 4; dactylus length about 0.75x propodus .......................................... L. longidactyla Vinogradov, 1964
- Pereopods 3 & 4; dactylus length much less than 0.5x propodus.................................................................................2
2. Pereopods 3 & 4 subchelate, formed by narrow, curved propodus folded against enlarged carpus, with row of strong setae along posterior margin ........................................................................................... L. chelifera Vinogradov, 1970
- Pereopods 3 & 4 not subchelate, with normal, relatively narrow carpus and propodus...............................................3
3. Pereopod 5; dactylus not fully retractile, only partly hooded.......................................................................................4
- Pereopods 5–7 all with similar, fully retractile and hooded dactyls.............................................................................6
4. Pereopods 6 & 7; only proximal part of dactylus retractile .................................................. L. falsa Vinogradov, 1970
- Pereopods 6 & 7 with normal, fully retractile and hooded dactyls...............................................................................5
5. Pereopod 5 weakly subchelate, formed by partly hooded, curved dactylus pressed against anterior margin of slightly distally swollen propodus. Antennae 2 slightly longer than A1 ................................... L. sphaerica Vinogradov, 1957
- Pereopod 5; dactylus relatively straight, not hooded, partly retractile proximally. Antennae 2 slightly shorter than A1 ........................................................................................................................................................... L. gruneri sp. nov.
6. Antennae 2; distal peduncular article with distinct lobe overlapping almost half following article medially............... ...................................................................................................................................... L. intermedia Vinogradov, 1960
- Antennae 2; distal peduncular article without medial lobe or with relatively small lobe.............................................7
7. Pereopod 7; length about 0.75x P6. Antennae 2 only slightly longer or subequal in length to A1................................ ................................................................................................................................................. L. clausi Bovallius, 1885
- Pereopod 7; length about 0.5x P6. Antennae 2 considerably longer than A1...............................................................8
8. Telson shorter than peduncle of U3..............................................................................................................................9
- Telson as long or longer than peduncle of U3.............................................................................................................11
9. Telson length about 0.5x peduncle of U3 ............................................................................... L. loveni Bovallius, 1885
- Telson length about 0.75x (or more) peduncle of U3.................................................................................................10
10. Pereonite 6 to urosomite 1 produced into dorsal denticles. Gnathopod 1; carpus with broadened distal margin, at least twice width propodus. Eyes reniform ........................................................................... L. serrata Bovallius, 1885
- Pereonites, pleonites and urosomites without dorsal denticles. Gnathopod 1; carpus with distal margin only slightly wider than propodus. Eyes with crystalline cones .................................................................. L. felina Bovallius, 1885
11. Pereopod 5; merus broadened, elongated-oval. Pleonite 1 with dorsal depression....... L. laticarpa Vinogradov, 1957
- Pereopod 5; merus linear, not broadened. Pleonite 1 without dorsal depression........................................................12
12. Head without rostrum. Pereopods 3–5; anterodistal corner of merus produced into small, sharp corner. Eyes reniform .............................................................................................................................................. L. pacifica Stebbing, 1888
- Head produced into distinct hook-shaped or rounded rostrum. Pereopods 3–5; anterodistal corner of merus not noticeably produced. Eyes with crystalline cones..................................................................................................... 13
13. Head produced into hook-shaped rostrum. Antennae 1; distal three articles fused. Pereopod 6; merus linear, without anterior bulge ........................................................................................................................ L. sayana Bovallius, 1885
- Head produced into broad, rounded rostrum. Antennae 1; distal articles separate. Pereopod 6; merus with distinct anterior, medial bulge .................................................................................................................... L. galatheae sp. nov.