Key to Male Vietnamese Rhopalopsole

1 Abdominal sternum 9 without vesicle (Fig. 2 in Harrison & Stark 2008) …………….….. R. alobata

1’ Vesicle present on abdominal sternum 9 (Fig. 2) …………………………………………………….... 2

2 Spine-like process on segment 10 forked (Figs. 6, 8 in Harrison & Stark 2008) …………………….… 3

2’ Spine-like process on segment 10 unforked (Fig. 1) ……………………………………………………… 4

3 Fused paraprocts deeply notched, posteromedian margin of tergum 9 with a slender, wide sclerotized area (Fig. 6 in Harrison & Stark 2008) ……….………………………………..… R. sinensis

3’ Fused paraprocts without notch, posteromedian margin of tergum 9 with a minute, triangular sclerotized area (Fig. 20.1 in Sivec et al. 2008) …………………….…………………. R. vietnamica

4 Posteromedian margin of tergum 9 bearing a single dark sclerotized area (Fig. 1) …………… 5

4’ Dark sclerotized area on posteromedian margin of tergum 9 divided or notched (Fig. 8) …..…... 6

5 Posterolateral spine on tergum 10 acute, welldeveloped, cerci with small terminal spine (Fig. 1) ………………………………………………. R. azun

5’ Posterolateral spine on tergum 10 poorly developed, scarcely projecting, cerci without spine (Fig. 40.1 in Sivec et al. 2008) …………………..……….……………….. R. sipang

6 Dark sclerotized areas on posterior margin of tergum 9 widely separated (Fig. 5) …… R. minima

6’ Dark sclerotized areas on posterior margin of tergum 9 separated by a narrow gap or notch (Fig. 8, and Fig. 5.1 in Sivec et al. 2008) ……………... 7

7 Dark sclerotized area on posterior margin of tergum 9 upturned and projecting beyond margin (Fig. 8); spine on tergum 10 apically truncate (Figs. 8,10) …………………………………. R. sapa

7’ Dark sclerotized area on posterior margin of tergum 9 flat and not projecting beyond margin (Fig. 5.1 in Sivec et al. 2008); spine on tergum 10 acute (Fig. 5.3 in Sivec et al. 2008) …….. R. tamdao