1 Corneal lenses present................................................................................. 2
- Corneal lenses absent................................................................................. 17
2 Two pairs of corneal lenses............................................................................. 3
- Only one pair of corneal lenses.......................................................................... 8
3 Pereopod 7 basis broad................................................................................. 4
- Pereopod 7 basis narrow................................................................................ 5
4 P7 carpus with anterior distal lobe; coxa1 inferior margin straight.......................... Haploops laevis Hoek, 1882
- P7 carpus without anterior distal lobe; coxa1 inferior margin rounded............................................................................................ Haploops quebecoisis Bellan-Santini Kaïm-Malka & Dauvin, 2018
5 Inferior lenses in the middle of the lobe head................................... Haploops sibirica Gurjanova, 1929
- Inferior lenses near or on the margin head.................................................................. 6
6 Inferior lenses near the margin head.......................................... Haploops dellavallei Chevreux, 1900
- Inferior lenses on the margin head........................................................................ 7
7 Inferior lenses on the margin, antennae = body length............................. Haploops nirae Kaïm-Malka, 1976
- Inferior lenses on the internal side of the margin, antennae = 1/2 body length........... Haploops tenuis Kanneworff, 1966
8 Only inferior lenses present (superior absent)............................................................... 9
- Only superior lenses present (inferior absent).............................................................. 10
9 Long setae on Md, back, telson, A1 <A 2.................................... Haploops longiseta Kaïm-Malka, 2010
- Few long dorsal setae, A1> A 2.............................................. Haploops proxima Chevreux, 1919
10 Pereopod 7 basis broad, A 2> body................................ Haploops gascogni Dauvin & Bellan-Santini, 1996
- Pereopod 7 basis narrow............................................................................... 11
11 Head truncated straight................................................................................ 12
- Head transversely truncated............................................................................ 15
12 A1> A 2.............................................................. Haploops antennata Kaïm-Malka, 2012
- A1 <A 2........................................................................................... 13
13 A1 length <A2 peduncle..................................................... Haploops descansa Barnard, 1961
- A1 length> A2 peduncle.............................................................................. 14
14 A1 length a little more A 2 peduncle; coxa 1 oval; U1 rami unequal length.......... Haploops oonah Lowry & Poore, 1985
- A1= 2/3 A2, A2 = body; coxa 1 triangular; outer side coxa 4 setose; U1 rami equal length.... Haploops truncata spec. nov.
15 A 2 = 1/2 body; corneal lenses great size......................................... Haploops tubicola Liljborg, 1856
- A 2 = 1/3 body; corneal lenses small size.................................................................. 16
16. U1–2 strongly armed....................................................... Haploops spinosa Shoemaker 1931
- U1–2 weakly armed............................................. Haploops fundiensis Wildish & Dickinson, 1982
17 Pereopod 7 basis narrow............................................................................... 18
- Pereopod 7 basis broad................................................................................ 24
18 P7 basis, merus and carpus, rectangular and slender (male)....................... Haploops abyssorum Chevreux, 1908
- P7 basis, merus and carpus, not rectangular and slender...................................................... 19
19 Coxa 4 heart-shaped.................................................................................. 20
- Coxa 4 not heart-shaped............................................................................... 22
20 Dorsal side of the body carinate, coxa 2 acute................................... Haploops vallifera Stephensen,1925
- Dorsal side of the body not carinate...................................................................... 21
21 A1= 8–9/10 A 2, A2= 2/3 body............................................... Haploops similis Stephensen, 1925
- Antennae longer than the body length..................... Haploops bjarnii Bellan-Santini Kaïm-Malka & Dauvin, 2018
22 A1= A 2 peduncle, coxa1 oval.................................................... Haploops lodo Barnard, 1961
- Antennae <1/2 body length............................................................................ 23
23 A1=A2=1/3 body............................................................... Haploops dauvini Peart, 2018
- A1=A2=1/2 body length......................................................... Haploops faroensis spec. nov.
24 Long dorsal tuft of setae absent......................................................................... 25
- Long dorsal tuft of setae present........................................................................ 26
25 P7 basis lobe exceeding ischium distal edge; A1<A2; coxa 4 not heart-shaped................................................................................................. Haploops antarctica Bellan-Santini & Dauvin, 2008
- P7 basis lobe not exceeding ischium distal edge; A1=A2; coxa 4 heart-shaped............ Haploops kaimmalkai Peart, 2018
26 Long dorsal tuft of setae (pereon 5–7 & pleon), P7 basis lobe triangular................... Haploops setosa Boeck, 1870
- Long dorsal tuft of setae (pereon 5–7 & pleon), P7 basis lobe rounded............................................27
27 Urosome 1 high upturned carina.............................................. Haploops carinata Liljeborg, 1856
- Urosome 1 carina straight.............................................................................. 28
28 Antenna length> body length, antennae very strong...... Haploops islandica Kaïm-Malka,Bellan-Santini & Dauvin, 2016
- Antenna length =1/2 body length............................................... Haploops robusta G.O. Sars, 1891