Key to the species of Fissiphallius

1 Eye mound armed with a single strong sharply pointed medial apophysis (see Pinto da Rocha 2004: fig. 1), tibia II enlarged in the male (see Pinto da Rocha 2004: fig. 4), free sternite IV with strong medial apophysis (see Pinto da Rocha 2004: fig. 2) F. martensi

­ Eye mound armed with a pair of medial apophyses, tibia II not enlarged in the male, free sternite IV without strong medial apophysis.......................................................... 2

2 Free sternite IV with a pair of small spiniform apophyses, anal operculum armed with strong spiniform apophysis ........................................................................................... 3

­ Free sternite IV unarmed, anal operculum without strong spiniform apophysis .......... 4

3 Free tergites I and II armed with a long spiniform medial apophysis (Figs 2, 4, 8), eye mound armed with two long spiniform apophyses (Fig. 2) .................... F. tucupi n. sp.

­ Free tergites I and II without strong spiniform medial apophysis (Figs 1, 3, 7), eye mound armed with two short spiniform apophyses (Fig. 1) ................... F. chicoi n. sp.

4 Free sternite V with a pair of short spiniform apophyses ............................................ 5

­ Free sternite V unarmed (see Martens 1988: fig. 28) .................................. F. spinulatus