Key to the species of Medionops n. gen.

1 Abdomen dorsally with remarkable pattern of spots, chevrons or bands...........................................2

- Abdomen dorsally with unremarkable pattern of very fine lines, almost unnoticeable................................6

2 Abdomen dorsally with five pairs of irregular dark gray spots forming two longitudinal bands.........................3

- Abdomen dorsally with five whitish gray chevrons fine marks..................................................4

3 Abdomen dorsally with big longitudinal pairs of irregular dark gray spots, almost touching (Figs 18 A–B); crista short, spiders more than 5 mm total length....................................................................... M. simla

- Abdomen dorsally with small longitudinal pairs of irregular dark gray spots, not touching (Fig. 10 A); crista absent (Fig. 9 K), spiders less than 3 mm total length.......................................................... M. claudiae n. sp.

4 Whitish gray chevron pattern on abdomen uniform among marks (Fig. 6 A); tip of embolus with several blade–shaped projections (Figs 2 J–L); female posterior plate with an internally projected median septum (Figs 4 J–L)........... M. blades n. sp.

- Whitish gray chevron pattern on abdomen not uniform among marks, the proximal being the largest (Figs 8 A–B; 14A–B); tip of embolus with a short terminal triangular projection (Figs 7 D–E; 12C–F) and females without septum on the internal posterior plate (Figs 7 G–I; 13J–L)............................................................................5

5 The proximal whitish gray chevron mark on abdomen is thick, longitudinal line reaching the pedicel (Fig. 14 A); crista and gladius absents (Figs 11 C,D,F; 13B,C)........................................................... M. murici n. sp.

- The proximal whitish gray chevron mark on abdomen is very fine, without longitudinal line reaching the pedicel (Fig. 8 A); crista short, and gladius with the traditional shape among nopine (Dupérré, 2014: fig.4)....................... M. cesari

6 Crista short but noticeable, not reaching one fourth of metatarsal length; spider more than 4.5 mm total length; males with embolus length more than three times the greater diameter of the bulb (Figs 19 G–H), known only from Venezuela (Fig. 21)........................................................................................... M. tabay n. sp.

- Crista unnoticeable (Figs 15 D–F); spiders less than 3.5 mm total length; males with embolus length over two times the largest diameter of the bulb (Figs 16 A–B), known only from southeast coast of Brazil (Fig. 21)............... M. ramirezi n. sp.