Figs 71–85, 144
Type material.Holotype: ³ from Brazil, Acre, Rio Branco, Reserva Extrativista de Humaitá [currently Reserva Extrativista Chico Mendes, comunidade Humaitá] [-10.5000, -69.7833], 12 April 1996, Equipe IBSP / SMNK leg. (IBSP 8803). Paratype: 1♀ from Brazil, Acre, Rio Branco, Reserva Extrativista de Catuaba [-10.0667, -67.6167], 9 April 1996, Equipe IBSP / SMNK leg. (IBSP 8675).
Etymology. The specific name refers to the collection locality of the holotype; noun in apposition.
Diagnosis. Males of S. humaitasp. nov. are distinguished from all other species of the genus by the palp lacking mRTA and with embolus wider at base and abruptly narrowed medially (Figs 81–82). Females resemble those of S. jurutisp. nov. by the epigyne with anterior atrium grooved (Figs 83, 106). They are distinguished from the latter species by the hexagonal shape of anterior atrium, vulva with internal ducts as wide as spermathecae and first turn mediad (anterior atrium rounded anteriorly, internal ducts half spermathecae width and first turn posteriad in S. jurutisp. nov.) (Figs 83–85).
Description. Male (holotype): Prosoma dark brown. Chelicerae as dark as prosoma. Legs as dark as prosoma, except coxae and anterior part of femora pale brown. Labium and edites dark brown. Sternum with wide dark brown margins. Opisthosoma yellowish gray; dorsally with brownish gray pattern of large irregular marks laterally and three median triangles followed by 2–3 chevrons down posterior half; ventrally with V-shaped lines of muscle sigilla extending down most of opisthosoma length and surrounded by white guanine crystals (Figs 71–72). Total length: 9.1. Prosoma: 4.1 long, 3.4 wide. Opisthosoma: 4.7 long, 2.8 wide. Eyes: diameters: 0.26, 0.21, 0.18, 0.18; interdistances: 0.25, 0.09, 0.45, 0.25, 0.13, 0.10. Legs: I: 13.0 (3.7, 1.8, 3.4, 3.2, 0.9); II: 12.8 (3.9, 1.8, 3.2, 3.0, 0.9); III: 9.8 (2.9, 1.5, 2.3, 2.3, 0.8); IV: - (3.3, 1.3, 2.7, rest of leg absent). Spination follows the generic pattern. Metatarsus III–IV with ventral distal preening combs. Palp: tibia with prolateral spines short; tegulum with retroproximal protrusion; TBE with apical projection curved with dorsal fin-like projection at tip; TBC wide, keel-like (Figs 75–77, 80–82).
Description. Female (paratype): Coloration pattern lighter than in male. Opisthosoma dorsally with elongate irregular marks laterally, few small spots on cardiac mark area and four median triangles down posterior half; ventrally with few scattered marks laterally and V-shaped lines of muscle sigilla, extending down most of opisthosoma length into U-shaped darker area (Figs 73–74). Total length 11.0. Prosoma: 4.5 long, 3.6 wide. Opisthosoma: 6.0 long, 3.4 wide. Eyes: diameters: 0.30, 0.24, 0.17, 0.25; interdistances: 0.25, 0.15, 0.50, 0.35, 0.20, 0.10. Legs (1243): I: 12.6 (3.6, 2.0, 3.2, 3.0, 0.8); II: 12.2 (3.7, 2.0, 3.0, 2.7, 0.8); III: 10.2 (3.2, 1.7, 2.2, 2.3, 0.8); IV: 11.8 (3.5, 1.5, 2.6, 3.2, 1.0). Spination follows the generic pattern. Metatarsus III–IV with ventral distal preening combs. Epigyne: epigynal field rectangular, longer than wide; anterior atrium trapezoid, slightly wider than long; median septum narrowed anteriorly, widest medially, 1.5 times longer than wide, with posterior margin rounded, slightly indented (Figs 78, 83). Vulva: glandular projection rounded, arising from duct at first turn; spermathecae oval (Figs 79, 84–85).
Distribution. Known from Brazil, southeastern state of Acre (Fig. 144).