Liropus Mayer, 1890

Alarcón-Ortega, Lucy C. & Carballo, José L., 2022, Description of a new species of Liropus (Crustacea, Amphipoda) from Puerto Vallarta, Pacific coast of Mexico, Zootaxa 5154 (5), pp. 528-536 : 535

Key of the World species of Liropus Mayer, 1890

Modified from Guerra-García (2004), Guerra-García et al. (2008), and Guerra-García and Hendrycks (2013).

1a. Pereopods 3 and 4 one-articulate......................................................................... 2

1b. Pereopods 3 and 4 two-articulate............................................... L. azorensis Guerra-García, 2004

2a. Pereopod 5 with three-articulate.......................................................................... 3

2b. Pereopod 5 with two-articulate........................................................................... 5

3a. Body dorsally smooth......................................................... L. nelsonae Guerra-García, 2003

3b. Body with an anterolateral projection in pereonites 2, 3 and 4 in males........................................... 4

4a. Head with two anterolateral acute projections.................................... L. willyi Guerra-García et al., 2018

4b. Head with two tiny dorsal tubercles, near the eyes............................... L. vitucoi Guerra-García et al., 2018

5a. Flagellum of antenna 1 two-articulate..................................................................... 6

5b. Flagellum of antenna 1 more than two-articulate............................................................. 7

6a. Gnathopod 2 propodus bearing a medial deep triangular cleft with roughly serrate margins distally... L. japonicus Mori, 1995

6b. Gnathopod 2 propodus palm providing one large grasping spine................................................ 8

7a. Head smooth......................................................................................... 9

7b. Head with one or two projections........................................................................ 10

8a. Pereonite 4 with a distally dorsal acute projection................................. L. gurui Guerra-García et al., 2015

8b. Pereonites 2, 3, 4 and 5 each with one dorsaldistal projection...................................... L. alarconi n. sp.

9a. Gnathopod 2 basis with a basal constriction.............................................. L. minimus Mayer, 1890

9b. Gnathopod 2 basis with parallel margins, lacking constriction............................... L. elongatus Mayer, 1890

10a. Head with a single anterior projection (= rostrum)....................................... L. gracilis Chevreux, 1927

10b. Rostrum absent, but a pair of anterolateral projections present............................... L. africanus Mayer, 1920

11a. Dorsal projection on pereonites 3, 4 and 5 in males, and 3 and 5 in females................................................................................................ L. cachuchoensis Guerra-García, Sorbe & Frutos, 2008

11b. Anterolateral projection on pereonites 2, 3 and 4....................... L. minusculus Guerra-García & Hendrycks, 2013

12a. Pereonites 2 and 3 with a pair of anterolateral acute and directed downwards projections............................................................................................... L. isabelensis Sánchez Moyano et al., 2015

12b. Pereonites 2 and 3 without dorsal or anterolateral projections.................... L. guerragarciai Mauro & Serejo, 2015