Amphidraus sacrificatus sp. nov.

Figs 9–10, 14

Type material. Holotype: ♂ from Conceição do Araguaia, 07°59’23.5”S, 49°24’28.8”W, Pará, Brazil, 16.I.2018, R.P.S Almeida. & F.V. Arruda leg. (MPEG 35027). Paratypes: 2♂, same data as holotype (MPEG 34602, IBSP 221863) .

Etymology. The specific epithet an adjective and refers to the heart-shaped membrane linked to proximal process on embolic disc (Fig. 10B), in allusion to human sacrificial rituals practiced by some ancient cultures.

Diagnosis. Differs from all Amphidraus species in having a blade-shaped embolus shaft (Figs 9F, 10 A–B) and a proximal process on embolic disc (pPED) linked to a heart-shaped membrane [Figs 9 C–D, 9F (white arrow), 10A–B, 10D]. In addition, the cymbial conductor (cc) is “Y-shaped” and faces retrolaterally (Figs 9E, 10C) (cc faces ventrally in all the other described species; see Figs 13A, 17A).

Description. Male holotype (MPEG 35027). Total length: 4.45. Carapace 2.13 long, 1.46 wide, 1.03 high. Ocular quadrangle 1.10 long. Anterior eye row 1.48 wide, posterior 1.19 wide. Legs 4312. Length of legs: I 3.79 (1.22 + 1.43 + 1.14); II 3.62 (1.19 + 1.28 + 1.15); III 4.46 (1.40 + 1.45 + 1.61); IV 4.75 (1.39 + 1.61 + 1.75). Palp (Figs 9 C–F, 10A–E): femur and patella with no modifications; RvTA with two short branches, the more ventral branch is reduced and rounded, and the more dorsal branch is larger, with acute tip (Figs 9D, 10D); RTA with wide base, shorter than the tibia and with acute tip (Figs 9D, 10 D–E); cymbium oval (Fig. 10E); tegulum with stout lobe curved to prolateral side (Figs 9C, 9F, 10A); embolic disc with three processes very close together on its distal portion: two short and rounded distal process (dPED) and one short and triangular ventral process (vPED) (Figs 9D, 9F, 10 A–B, 10D); embolic filament (ef) very short, approximately 1/5 the length of embolus shaft (Figs 9F, 10 A–B). Color in alcohol (Figs 9 A–B): cephalic area black with yellow setae near the eyes; thoracic area laterally black and centrally dark brown with yellow setae on median-posterior portion; abdomen dorsally variegated with black and dark brown, and with a longitudinal stripe of white setae; ventrally variegated with brown; legs I almost black and legs II–IV dark brown; tarsi pale in all legs.

Female. Unknown.

Note. The RvTA was interpreted herein as an apophysis with two branches (Figs 9D, 10D). However, in other Amphidraus species, such as A. araripe sp. nov., these branches are not fused and therefore interpreted as two distinct apophyses: one RvTA and one ITA (Figs 11F, 13B). The processes placed proximally on embolic disc and herein named as the pPED in A. sacrificatus sp. nov. and A. boomerang sp. nov. (Figs 7C, 8A) are possibly homologous. However, in A. sacrificatus sp. nov. it is linked to a heart-shaped membrane [Figs 9C, 9F (white arrow), 10A–B]. The homologies of all these structures across the genus need to be tested in future studies.

Distribution. Known only from the type locality (state of Pará, Brazil) (Fig. 14).

Natural History. The specimens were collected from an ecotonal zone between the Cerrado and the Amazon rainforest.