Nikoides, Paul'son, 1875

Komai, Tomoyuki & Hirabayashi, Isao, 2021, A new species of the processid shrimp genus Nikoides Paul’son, 1875 (Decapoda: Caridea) from Japan, Zootaxa 5057 (1), pp. 114-126 : 124-125

Key to species of Nikoides

1. Telson with 4–6 dorsolateral spiniform setae on either side........................... N. multispinatus Hayashi, 1981

1. Telson with 2 pairs of dorsolateral spiniform setae........................................................... 2

2. Rostrum very short, not reaching corneal base; pereopod 4 ischium unarmed or armed with 1 spiniform seta............. 3

2. Rostrum reaching beyond corneal base to distal corneal margin; pereopod 4 ischium with 2 spiniform setae.............. 4

3. Pereopods 3 and 4 ischium each with 1 spiniform setae................................ N. steinii ( Edmondson, 1935)

3. Pereopods 3 and 4 ischium unarmed.......................................... N. boraboraensis Burukovsky, 2002

4. Rostral dorsal tooth located at subdistal or middle position..................................................... 5

4. Rostral apex bifid (otherwise unarmed on dorsal margin) or with dorsal tooth subapical in position..................... 6

5. Rostrum with dorsal tooth relatively large, located at middle position; pleuron 5 with minute denticle on posteroventral margin; distomesial tooth of antennular stylocerite blunt, less produced than distolateral tooth...... N. maldivensis Borradaile, 1915

5. Rostrum with dorsal tooth relatively small, located as subdistal position (distal 0.25 of rostral length); pleuron 5 with rounded posteroventral margin; distomesial tooth of antennular stylocerite acute, more produced than distolateral tooth................................................................................................ N. subdistalis n. sp.

6. Telson posterior margin not produced into spine; antennular stylocerite rounded or rectangular, rarely with minute distolateral point; antennal basicerite devoid of ventrolateral distal spine and ventral projection; pereopods 3–5 propodi without row of tufts of short setae on extensor margins in males................................................................. 7

6. Telson posterior margin produced medially into spine; antennular stylocerite with pointed or spiniform distolateral and distomesial angles; antennal basicerite with ventrolateral distal spine and small projection on ventral face; pereopods 3–5 propodi with row of tufts of short setae on extensor margins in males........................................... 10

7. Pleomere 6 with posterolateral process terminating in spine.................................................... 8

7. Pleomere 6 with posterolateral process blunt or truncate distally................................................ 9

8. Antennular stylocerite quadrate with truncate distal margin; scaphocerite with distolateral spine not reaching distal margin of lamella; pereopod 5 propodus with subterminal spiniform setae on flexor margin................ N. sibogae de Man, 1918

8. Antennular stylocerite rounded; scaphocerite with distolateral spine reaching distal margin of lamella; pereopod 5 propodus without subterminal spiniform setae on flexor margin................................... N. plantei Burukovsky, 2007

9. Scaphocerite with distolateral spine well separated from lamella and reaching as far as it; pereopod 2 carpus divided into 23–24 segments in left and 43–49 segments in right; pereopod 5 propodus with 2 spiniform setae on flexor margin..................................................................................... N. schmitti Manning & Chace, 1981

9. Scaphocerite with distolateral spine contiguous to lamella and not reaching distal margin of it; pereopod 2 carpus divided into 28–33 segments in left and 90–101 segments in right; pereopod 5 propodus unarmed on flexor margin................................................................................................. N. longicarpus Noël, 1986

10. Pleuron 5 pointed at posteroventral angle but not acute; antennular stylocerite sharply pointed at distolateral and bluntly pointed at distomesial angle; antennal basicerite with ventrolateral distal spine; pereopod 3 merus usually with 5 spiniform setae.................................................................................... N. danae Paul’son, 1875

10. Pleuron 5 with posteroventral denticle; antennular stylocerite sharply pointed at both distolateral and distomesial angles; antennal basicerite without ventrolateral distal spine; pereopod 3 merus usually with 4 spiniform setae.................................................................................................. N. gurneyi Hayashi, 1975