Amphidraus nigrigenu sp. nov.

Figs 11–12

Type material. Holotype: ♂ from Juruti, 02°30'27.4"S, 56°10'39.5"W, Pará, Brazil, 17–21.XII.2012, A.S. Alves et al. leg. (MPEG 32688).

Etymology. A composed Latin noun (nigri + genu), meaning “black-knee”, in reference to the dark markings on the middle portion of the legs.

Diagnosis. The embolic disc and embolus of A. nigrigenu sp. nov. are similar to those of A. duckei, A. santanae, A. colombianus and A. simplex sp. nov.: there are two dPED and the vPED is proximal and projects retrolaterally; also, the embolus is thicker and sickle-shaped in these species (Fig. 12 C). However, A. nigrigenu sp. nov. can be distinguished by the short and rounded RvTA with two teeth on the border (Fig. 12 D), being slender and sinuous in A. duckei and A. colombianus, short with one tooth in A. santanae (see Galiano 1967: fig. 4), and finger-shaped in A. simplex sp. nov. (Fig 14 D).

Description. Male holotype (MPEG 32688). Total length: 2.93. Carapace 1.44 long, 1.03 wide and 0.80 high. Ocular quadrangle 0.57 long. Anterior eye row 1.10 wide, posterior 0.91 wide. Legs: 3412. Length of leg I 2.20 (0.72 + 0.76 + 0.72); II 2.16 (0.72 + 0.76 + 0.68); III 2.96 (0.95 + 0.95 + 1.06); IV 2.92 (0.87 + 0.95 + 1.10). Palp (Figs 12 A–D): femur with subproximal ventral projection (Figs 12 A, 12D); tibia with reduced RTA and depression below the apophyses (Figs 12 B, 12D); embolic filament longer than straight, sclerotized portion (Fig. 12 C). Color in alcohol: thoracic area brown and cephalic area black; abdomen dorsally almost black; ventrally pale; legs with dark spots (Figs 11 A, 11B).

Female. Unknown.

Distribution. Known only from the type locality (Brazil, Pará) (Fig. 31).

Note. Although we have found large variation in male palp structure of A. santanae, which could include the palp of the holotype of A. nigrigenu, we preferred to recognize this male as a different species, since the unusual morphology of the palp is accompanied by a different color pattern in legs and palps (black).