Loxosceles niedeguidonae de Andrade, Bertani, Nagahama & Barbosa 2012

Male(holotype). Total length (without chelicerae) 6.01. Carapace 3.29 long, 3.1 wide. Eye size: ALE: 0.2, PME: 0.22, PLE: 0.18. Clypeus: 0.32. Interocular distance - PME and PLE: 0.04, PME and ALE: 0.2. Leg formula: II, IV, I, III. Legs and palp length and width in Table 1. Labium 0.75 long, 0.42 wide. Sternum 1.59 long, 1.48 wide. Femur I 2.58 times longer than the carapace. Palpal femur 7.13 times longer than wide, tibia 2.81 times longer than wide (Fig. 2), tarsus almost two times longer than wide (Figs 3–4). Bulb suboval, slightly shorter than tarsus length. Embolus almost straight, approximately two times longer than bulb width, without carina (Fig. 4). Cephalic region of carapace covered by many long setae. Carapace with pars cephalic and chelicerae light brown (Fig. 1). Pars thoracica pale yellow, carapace border mottled, light brown (Figs 1, 9). Legs and palps pale yellow, covered by short grayish setae. Coxae and sternum pale yellow, labium and endites brown. Abdomen covered with grayish setae. Loxosceles niedeguidonae sp. n. Male holotype. Length/width of right legs and palpal segments. Palp I II III IV Tarsi 0.75/0.46 1.9/0.1 1.75/0.12 1.37/0.12 1.75/0.12 Metatarsi --- 11.4/0.2 13.87/0.12 2.05/0.25 12.12/0.25 Tibiae 1.55/0.55 10.1/0.3 12.12/0.37 7.62/0.25 9.37/0.37 Patellae 0.7/0.45 1.3/0.4 1.25/0.5 1.25/0.5 1.25/0.5 Femora 2.64/0.37 8.5/0.6 10.25/0.62 8.0/0.62 9.12/0.62 Total length 5.64 33.2 39.24 20.29 33.61 Female (paratype MNRJ 04360) Total length (without chelicerae) 7.35. Carapace 3.79 long, 3.71 wide. Eye sizes: ALE: 0.22, PME: 0.16, PLE: 0.18. Clypeus: 0.32. Interocular distances - PME and PLE: 0.05, PME and ALE: 0.24. Leg formula: II, I, VI, III. Legs and palp length and width in Table 2. Labium 0.7 long, 0.54 wide. Sternum 1.85 long, 1.78 wide. Femur I 1.58 times longer than carapace. Palpal femur 5.0 times longer than wide, tibia 3.5 longer than wide, tarsus incrassate (Fig. 6). Spermathecae with long, straight, apically enlarged seminal receptacles; transversal plate narrow, weakly sclerotized; atriobursal orifices well visible, ovals, positioned on the internal edge of the central windows; dorsal part of bursa copulatrix weakly sclero- tized (Figs 7–8). Coloration as in male, but darker (Fig. 12). Tarsi and tibiae of palps reddish-brown. Loxosceles niedeguidonae sp. n. Female paratype (MNRJ 04360). Length/width of right legs and palpal segments. Palp I II III IV Tarsi 1.42/0.39 1.58/0.08 1.58/0.16 1.18/0.16 1.26/0.16 Metatarsi --- 6.24/0.16 7.19/0.16 5.85/0.16 6.95/0.16 Tibiae 1.11/0.32 6.32/0.32 6.79/0.32 4.42/0.32 5.45/0.32 Patellae 0.47/0.32 1.11/0.47 1.03/0.32 1.03/0.39 1.11/0.47 Femora 1.58/0.32 6.0/0.63 6.4/0.63 5.45/0.47 5.85/0.63 Total length 4.58 21.25 22.99 17.93 20.62

Known only from Parque Nacional Serra da Capivara, Piauí State, Brazil.