Loxosceles Heineken & Lowe, 1832

Taucare-Ríos, Andrés, Brescovit, Antonio D. & Villablanca, Javier, 2022, A new species of Loxosceles Heineken & Lowe, 1832 (Araneae: Sicariidae) from Chile, Revista Chilena de Entomología (Rev. Chil. Entomol.) 48 (1), pp. 157-164 : 158-160

Genus Loxosceles Heineken & Lowe, 1832

Loxosceles vicentei sp. nov. ( Figs. 1 A-B, 2A-D, 3, 4 A-B, 5) Diagnosis. Loxosceles vicentei sp. nov. can be confused in Chile only with L. coquimbo , but can be distinguished by the presence of dark-brown spots on carapace ( Figs. 1 A-B). The male resembles L. coquimbo by its palp with a globose bulb, but differs by having a long embolus, straight with a truncated tip ( Figs. 2 A-C), while in L. coquimbo the embolus is short and sinuous at tip; in other species of laeta species-group such as L. laeta and L. surca Gertsch, 1967 the embolus is slender and curved. In L. vicentei sp. nov. the male palpal tibia is shorter (1.5 long, 0.6 wide) ( Figs. 2 A-B) than in L. coquimbo (2.1 long, 0.5 wide). The females can be distinguished from other Chilean species by the spermatheca with large base and two slender, curved receptacles in both sides. The seminal receptacles of females of L. vicentei sp. nov. and L. coquimbo are similar, however in the new species the distance between the base of the receptacles is larger (1.3 times) than in L. coquimbo ( Fig. 2D ).

Etymology. The specific name is a patronymic for Vicente Villablanca, son of Javier Villablanca and the collector of the type material.

Type material. Holotype male ( MNHNCL 8371 ): Chile, IV Región de Coquimbo , Vicuña, Fundo el Calvario, near to Juntas del Toro , 29°58’30.97”S 70°6’11.86”W, 2,050 m a.s.l, manual collecting under rocks, 14 October 2021, V. Villablanca Miranda, J. Villablanca Rivera & A. Taucare-RÍos leg . Paratypes. Chile: 1 female ( LEULS 003 ) , 2 males ( LEULS 004 ), same locality, date and collectors as holotype .

Additional material examined: 1 female and 4 immatures, same collection data as for holotype ( MNHNCL 8372 ) ; 1 immature, 14 November 2019, same locality of holotype, J. Villablanca Rivera & V. Villablanca Miranda leg. ( MNHNCL 8373 ). III Región de Atacama, Copiapó , 27°17’58.91”S 70°23’6.08”W, 340 m a.s.l , 2 females, collected under rocks, 8 December 2020, J. Villablanca Rivera & V. Villablanca Miranda leg. ( MNHNCL 8374 ). III Región de Atacama, Copiapó , 26°58’59.36”S 70° 0’25.07”W, 1,743 m a.s.l , 3 females, collected in rodent burrow, 16 December 2019, J. Villablanca Rivera & V. Villablanca Miranda ( LEULS 005 ) .

Description. Male holotype: Measurements: Total length (without chelicerae) 7.5. Carapace 3.4 long, 3.0 wide. Clypeus length 0.21. Carapace light brown, longer than wide, narrowed anteriorly, dorsally without the typical ʻviolinʼ pattern and the cephalic zone reddish-brown. Carapace with 3 small lateral brown spots in each side, 1 central dark-brown spot on thoracic furrow and 2 brown spots near to cephalic zone ( Fig. 1B ). Sternum 1.9 long, 1.5 wide. Chelicerae red brown. Eye diameters: ALE = 0.18, PME = 0.19, PLE = 0.18. Opisthosoma uniformly grey, longer than wide. Legs yellowish. Leg I: 6.9, 1.5, 7.5, 7.5, 1.8, total (25.2). II: 7.5, 1.5, 8.1, 8.2, 1.8, (27.1). III: 6.2, 1.1, 7.1, 7.4, 1.9, (23.7). IV: 8.3, 1.9, 7.7, 8.2, 1.5, (27.6). Leg formula 4213. Palp: femur 3.5 long, 0.4 wide, patella 0.64 long, 0.58 wide, tibia 1.5 long, 0.6 wide. Cymbium (0.58 long), rounded apically, shorter than the tibia. Palp with bulb globular and a straight and long embolus with a truncated tip ( Figs. 2 A-C).

Female: Measurements: Total length (without chelicerae) 8.3. Carapace long 3.9, 3.1 wide. Clypeus length 0.25. Carapace yellowish with brown spots strongest marked and without reddish-brown color in the cephalic zone ( Fig. 1A ). Eye diameters: ALE = 0.18, PME = 0.22, PLE = 0.19. Leg I: femur 6.6, patella 1.1, tibia 7.5, metatarsus 7.5, tarsus 1.6, total (23.1). II: 7.5, 1.2, 8.6, 9.1, 1.8, (25.2). III: 6.2, 1.1, 6.1, 7.2, 1.3, (21.9). IV: 6.9, 1.6, 7.0, 8.2, 2.0, (25.7). Leg formula 4213. Palp yellow, except for orange tibia and tarsus. Opisthosoma uniformly grey, longer than wide. Legs yellowish. Palp: femur 1.22, patella 0.39, tibia 1.3, tarsus 1.4. Spermatheca with broad base and narrow-elongated receptacles, with longer internals

( Fig. 2D ). Natural history. This species lives in semi-arid environments in rocky areas, associated with grass and low vegetation ( Fig. 3 ). The vegetation is frequently of the hawthorn type, such as cacti, with stunted shrubs, deciduous trees and semi-desert grasslands ( Luebert & Pliscoff 2006). This species is absent in urbanized environments and is endemic to the semi-arid region of Chile. Individuals of Loxosceles vicentei sp. nov. were collected only under rocks in mountain natural environments. Specimens of both sexes were often observed together in the same microhabitats ( Figs. 4 A-B). Despite the presence of so many rocks in the area, a low population density was found. Remains of beetles consumed in the nests were observed.

Distribution. Chile, Atacama and Coquimbo regions ( Fig. 5 ).

Figures

Figures 1A-B. Loxosceles vicentei sp. nov. Carapace of female and male. A. Female paratype. B. Male holotype. Scale bar: 1 mm. / Loxosceles vicentei sp. nov. Cefalotórax de hembra y macho. A. Hembra paratipo. B. Macho holotipo. Barra de escala: 1 mm.

Figures 2A-D. Loxosceles vicentei sp. nov. Fundo el Calvario, Juntas del Toro, Vicuña, Coquimbo. A. Holotype male’s palp, prolateral view. B. Retrolateral view. C. Detail of the bulb and embolus, retrolateral view. D. Paratype female, seminal receptacles, dorsal view. Scale bars: 0.5 mm for A and B, 0.2 mm for C and 0.5 mm for D. / Loxosceles vicentei sp. nov. Fundo el Calvario, Juntas del Toro, Vicuña, Coquimbo. A. Palpo del macho holotipo, vista prolateral. B. Vista retrolateral. C. Detalle del bulbo y émbolo, vista retrolateral. D. Hembra paratipo, receptáculos seminales, vista dorsal. Barra de escala: 0,5 mm para A y B, 0,2 mm para C y 0,5 mm para D.

Figure 3. Habitat of Loxosceles vicentei sp. nov. in the type locality. / Hábitat de Loxosceles vicentei sp. nov. en la localidad tipo.

Figures 4A-B. Live specimens of Loxosceles vicentei sp. nov. found under rocks in type locality (photography: Vicente Villablanca). A. Female paratype, dorsal view. B. Male holotype, dorsal view. / EspecÍmenes vivos de Loxosceles vicentei sp. nov., hallados bajo rocas en la localidad tipo (fotografÍa de Vicente Villablanca). A. Hembra paratipo, vista dorsal. B. Macho holotipo, vista dorsal.

Figure 5. Geographic distribution records of Loxosceles vicentei sp. nov. in Chile. / Registros de distribución geográfica de Loxosceles vicentei sp. nov. en Chile.