Loxosceles niedeguidonae, Goncalves-de-Andrade, Rute Maria, Bertani, Rogerio, Nagahama, Roberto Hiroaki & Barbosa, Maria Fatima Ribeiro, 2012

Goncalves-de-Andrade, Rute Maria, Bertani, Rogerio, Nagahama, Roberto Hiroaki & Barbosa, Maria Fatima Ribeiro, 2012, Loxosceles niedeguidonae (Araneae, Sicariidae) a new species of brown spider from Brazilian semi-arid region, ZooKeys 175, pp. 27-36 : 28-33

Loxosceles niedeguidonae sp. n. Figures 1-13

Type material.

Holotype: male: Brazil, Piauí, Coronel José Dias, Boqueirão do Sítio da Pedra Furada - Toca, 8°51'S, 42°33'W, 16 March 2009, R. M. Gonçalves-de-Andrade & Maria Fátima Ribeiro Barbosa (MNRJ 04359).

Paratype female (MNRJ 04360) with same data as for holotype.

Other material examined.

Loxosceles chapadensis . Holotype: Male: Brazil, Bahia, Palmeiras, Chapada Diamantina National Park (12°28'S, 41°25'W), 15 February 2008, R. Bertani, C. S. Fukushima & R. H. Nagahama, (MNRJ 6047); Paratypes: Brazil, Bahia: 1 female, with same data as for holotype (MNRJ 6048); 3 females and 1 male, Lençóis, Chapada Diamantina National Park (12°33'S, 41°23'W), 19 February 2008, same collectors as for holotype, (MNRJ 6049); 1 female, Iraquara, Fazenda Pra- tinha (12°21'S, 41°32'W), 16.II.2008, same collectors as for holotype, (MNRJ 6050).

Diagnosis.

Males can be readily distinguished from other species, except Loxosceles chapadensis by the following characters in combination: Palpal tibia more than 1.5 times longer than tarsus, embolus 1.5-1.8 times longer than diameter of tegulum, arising at distal half of tegulum, distally thin but not filiform and hardly curved, particularly not in distal direction (Fig. 2). Males differ from Loxosceles chapadensis by palpal tarsus almost two times longer than wide (Figs 2-4), embolus less curved (Fig. 4) and faded lateral dentate dark bands on the dorsal side of the carapace (Fig. 9). Females can be recognized by the following characters in combination: A narrow transversal plate in the spermathecae, straight, apically enlarged seminal receptacles and incrassate palpal tarsus, which is broader than palpal tibia (Figs 6-8).

Etymology.

The specific name is a patronym in honor of Dr Niéde Guidon, one of the most important Brazilian archeologists, internationally acknowledged for her archeological work and her battle for the preservation of archeological sites in Brazil and the conservation of remnant patches of Caatinga vegetation, as well as important social work, especially in the Parque Nacional da Serra da Capivara.

Description.

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.

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.

Discussion.

The female Loxosceles niedeguidonae sp. n. can undoubtedly be included in the gaucho group of Gertsch (1967) due to spermathecae bearing a transverse plate (Figs 7-8), which is characteristic of the group. However, the male resembles species of the laeta group due to its long palpal tibia (Fig. 2). These characteristics are also found in the recently described species Loxosceles chapadensis with which Loxosceles niedeguidonae sp. n. seems to be closely related. As already discussed by Bertani et al. 2010, the long palpal tibia of males of Loxosceles chapadensis (and now, Loxosceles niedeguidonae sp. n.) could be an homoplasy with species of the laeta and spadicea groups or a plesiomorphy, indicating a more basal position of the species in the gaucho group relative to these other species ( Bertani et al. 2010). Despite these shared characteristics they can be separated by genitalic and somatic characteristics. The male has a straighter embolus (Figs 3-4), palpal tarsus almost two times longer than wide and color pattern are not very similar to the typical gaucho pattern, i. e. lateral dentate dark bands on the dorsal side of carapace. The male resembles an individual of the laeta group due to its light-brown coloration and faded dentate dark bands on the carapace (Figs 1-9, 11). The female can be easily separated by the narrow transversal plate in spermathecae (Figs 7-8) and in- crassate palpal tarsus (Fig. 6), which is like the female Loxosceles adelaida , gaucho group (Gertsch, 1967), but more dilated than the latter.

The distinct, but close geographical distribution of Loxosceles chapadensis and Loxosceles niedeguidonae sp. n. in Northeastern Brazil provides an additional indication that these two species are closely related.

Natural History.

Specimens of Loxosceles niedeguidonae sp. n. were found in the locality of "Buraco da Pedra Furada". The male was collected over the ground and the female in a rock crevice close to a cave mouth. The arenitic walls in the Parque Nacional Serra da Capivara have innumerous crevices that make typical retreats for brown recluse spiders (Figs 13-14). However, despite the presence of so many crevices, a low population density was found in the analyzed ecotope.

Distribution.

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