Ambicholestes, Just, 1998

Just, Jean, 2017, A fresh look at the higher classification of the Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 12: with a key to all taxa, Zootaxa 4320 (2), pp. 321-338 : 336

K Ambicholestes

1. Gnathopod 2 article 2 anterior margin with 2 or 3 anterior lobes, lobe margins with medial short, hollow setae. Coxal plate 1 posteroventral margin with row of sharp teeth............................................................... 2

- Gnathopod 2 article 2 anterior margin straight, without specialised setae. Coxal plate 1 posteroventral margin smooth..... 3

2. Gnathopod 2 article 2 with bilobed anterolateral margin; rostrum absent..................... A. magellani ( Just, 1984a)

- Gnathopod 2 article 2 with trilobed anterolateral margin; rostrum present, depressed.............. A. trilobatus Just, 1998

3. Rostrum pointed..................................................................................... 4

- Rostrum broadly rounded to nearly absent................................................................ 5

4. Cephalic surface in rostra1 area smooth; antenna 2 as long as head and pereonites 1–7 combined; coxal plate 1 and gnathopod 2 basis simple..................................................................... A. cygnatratus Just, 1998

- Rostral area hirsute; antenna 2 as long as head and pereonites 1–4 combined; coxal plate 1 with posterior teeth; gnathopod 2 basis with anterior flange and mediolateral row of hollow setae............................ A. crassicornis Just, 1984a

5. Midanterior cephalic margin forming a broadly rounded, projecting setulose lobe; antenna 2 hirsute.... A. poorei Just, 1998

- Midanterior cephalic margin weekly convex, frons and epistome squamose (not confirmed for A. nanshaensis ); antenna 2 smooth............................................................................................. 6

6. Pereopods 5 and 6 basis with several short, stout, heavily plumose setae on anterior margin and lateral face, and one on poste- rior margin....................................................................... A. squamiferus Just, 1984

- Pereopods 5 and 6 basis apparently naked............................................ A. nanshaensis ( Ren, 2006)