Key to males of Metalibitia species

1. Free tergite III with similar-sized tubercles (Figs 1 D; 2A, B)................................................... 2

- Free tergite III with tubercles of different sizes (Figs 1 B, C; 2D)................................................3

2. Free tergite II with two higher lateral tubercles, three tubercles united at the base to apex on paracheliceral projections (Fig. 1 A), femur IV with retroapical ventral apophysis long and rounded and retrolateral spine on tibia IV (Figs 5 A, E; 7E).................................................................................................. M. adunca .

- Free tergite II with similar sized tubercles, two tubercles on paracheliceral projections (Figs 1 D; 2A, B) and tibia IV with tubercles and small tubercles (Figs 7 D, H; 8A, F)............................................................ 4

3. Femur IV with one retrolateral rounded tubercle on distal portion higher than the other ones (Figs 5 C, G; 6D, I)..........5

- Femur IV with retrolateral distal tubercles of similar sizes (Figs 5 B, F)................................. M. argentina

4. Tubercles of coxa II falciform, surpassing the apex of coxa (Figs 2 C, E), retrolateral region of trocanter IV smooth, femur IV straight (Figs 6 C, H, E, J)...............................................................................8

- Tubercles of coxa II straight, not exceeding the apex (Figs 2 A, B), retrolateral region of trocanter IV with one or more tuber- cles, femur IV curved (Figs 6 F, G)........................................................................6

5. Tibia IV with apophyses on ventral region (Fig. 8 I).................................................... M. tibialis

- Tibia IV with only tubercles (Fig. 7 C)............................................................. M. borellii

6. Trochanter IV with row of five retroventral tubercles united at base, femur IV with one retroapical tubercle with pointed apex (Figs 6 B, G), tibia IV with prolateral row of tubercles (Figs 8 B, G)................................... M. rosascostai

- Trochanter IV with group of retroventral tubercles, femur IV with retroapical similar-sized tubercles (Figs 5 D, H; 6A, F), apex of tibia IV with similar-sized of all tubercles (Figs 7 D, H; 8A, F)................................................ 7

7. Pedipalpal femur with six ventral tubercles, three ventroapical tubercles (Fig. 3 C) and median portion of leg trochanter IV with set of five-seven tubercles (Figs 5 D, H)......................................................... M. brasiliensis

- Pedipalpal femur with nine ventral tubercles, being two of them ventroapical (Fig. 3 D), and distal portion of leg trocanter IV with group of four tubercles (Figs 6 A, F)...................................................... M. paraguayensis

8. Free tergite III with median tubercles fused and highest, coxa II with retrolateral tubercle (Fig. 2 E)...... M. abuna sp. nov.

- Free tergite III with central tubercles separated, coxa II only with prolateral tubercle (Fig. 2 C)............. M. santaremis