Loxosceles troglobia, Souza & Ferreira, 2018

Souza, Maysa F. V. R. & Ferreira, Rodrigo L., 2018, A new highly troglomorphic Loxosceles (Araneae: Sicariidae) from Brazil, Zootaxa 4438 (3), pp. 575-587 : 576-580

Loxosceles troglobia sp. nov.

urn:lsid:zoobank.org:act:CB1515BB-A0BE-4E4D-9C8A-BF40FA3789D9

Type material. Male holotype (ISLA 47462), BRAZIL: Bahia, Malhada, Tapera d´água cave (14°31'2.17"S, 43°40'58.23"W), 11/IX/2016, R.L. Ferreira col. Paratypes: male II (ISLA 47463), male III ( ISLA 47464), male IV ( IBSP 213031 ), female I (ISLA 47465), female II ( ISLA 47466), female III ( IBSP 213032 ) and female IV (ISLA 47467), same date, locality and collector as the holotype .

Other material examined. Two adult females, same date, locality and collector as the type material; one adult female from Tabocas cave (14°35’13.11”S, 43°41’10.87”W), Iuiu, Bahia, Brazil, 22/XI/2016, R.L. Ferreira col.

Specimens preparation and condition. All the type specimens are preserved in 70% ethanol. The genitalia of all females, the left palp of the males I, III and IV and the right palp of the males II and IV were dissected and stored in a vial with the specimens. The same applies to the right legs I-IV of the male III and the right legs I, III and IV of female II. In the male I (holotype), the left leg III is missing (the coxa remains and is smaller than others) and the left leg IV is detached and stored with the specimen. Considering the male paratypes, the left palp of the male II, the left leg III of the male III and the right leg IV of the male IV are missing. The left legs I and II of the male IV are detached and preserved in the same vial with the specimen. Regarding the female paratypes, the opisthosoma is detached from the prosoma in females I, II and III and is stored with the specimen. The right leg II of the female II is missing.

Etymology. The specific epithet is a Latin word meaning “troglobiont”, an animal that is restricted to caves.

Diagnosis. Loxosceles troglobia sp. nov. can be readily distinguished from the other species of the genus by presenting depigmented and extremely reduced eyes ( Figs 2, 5 , 13, 16 , 24 ). It belongs to the gaucho group (sensu Gertsch 1967) because the males present the tibia and the tarsus of the pedipalp with similar lengths (tibia/tarsus = 0.98–1.2) and the females have the seminal receptacles connected by a sclerotized transverse plate. The new species differs from the other species of the gaucho group by presenting lighter body coloration, absence of dark bands on lateral parts of the carapace and more elongated legs ( Figs 1–3 , 12–14 , 24–30 ). The females of the new species ressemble those of L. niedeguidonae by presenting the spermathecae with a thin and weakly sclerotized transversal plate connecting the straight seminal receptacles ( Figs 17–20 ). However, L. niedeguidonae can be distinguished from the new species by the shape of the transversal plate and the seminal receptacles and by presenting an incrassate palpal tarsus ( Gonçalves-de-Andrade et al. 2012). The remaining species of this group, conversely, have a broad and strongly sclerotized plate in the spermathecae ( Gertsch 1967; Bertani et al. 2010). Considering the male palp, the basally thick embolus is shared with the other members of the group and the thin and downward curving tip of this structure is a distinctive feature of the new species ( Figs 6–11 ). The values of the ratio between length and width of the palpal femur and tibia of the new species are closer to those presented by L. similis , L. variegata and L. gaucho when compared with those presented by L. chapadensis and L. niedeguidonae . The same applies to the values of the ratio between the lengths of palpal tibia and tarsus. The leg formula is shared with L. adelaida and L. similis , as well as with the females of L. gaucho , L. chapadensis and L. niedeguidonae .

Description of males. Coloration. Carapace pale yellow, anterior half of pars cephalica and median groove slightly darkened (light orange). Inconspicuous moderate orange Y-mark posteriorly on pars cephalica ( Fig. 2 ). Sternum pale yellow ( Fig. 4 ). Chelicerae ( Fig. 5 ), labium and endites pale yellow (strong yellow in males II and III), darkened (strong reddish brown) in their distal portion. Palps pale yellow (with the extremities of the segments brownish orange in male II) ( Figs 6–11 ). Legs pale yellow (strong yellow in paratypes) with the extremities of each segment darkened (strong reddish brown). Opisthosoma yellowish gray (pale yellow in paratypes) ( Fig. 1 ).

Prosoma. Carapace 2.43 (2.26–2.37) long, 2.11 (1.98–2.08) wide. Eyes without pigment ( Fig. 2, 5 , 24 ). Eye sizes and interdistances: ALE 0.05 (0.06), PME 0.07 (0.06–0.08), PLE 0.05 (0.06–0.07), PME-PLE 0.35 (0.31– 0.32), PME-ALE 0.25 (0.21–0.22), ALE-PLE 0.05 (0.04–0.06), PME interdistance 0.06 (0.05–0.07). The right PLE of male IV is atrophied, being reduced to a small white spot. Clypeus 0.28 (0.27–0.3). Labium 0.55 (0.5–0.53) long, 0.52 (0.43–0.5) wide. Sternum 1.23 (1.19–1.22) long, 1.26 (1.16–1.18) wide. Long setae or bristles distributed in parallel rows on the pars cephalica, two rows on each half of pars thoracica and a single row on the side margin of the carapace. Thinner and shorter setae dispersed on carapace ( Figs 2, 3 , 24 ). Sternum, labium, chelicerae and endites covered by long setae interspersed with shorter and thinner setae ( Figs 4, 5 ).

Opisthosoma. Oval, without protuberances and densely coated by short setae ( Fig. 1 ).

Legs and palp. Leg formula II, IV, I, III. Legs length: leg I: femur 7.4 (6.44–6.97), patella 0.95 (0.84–0.86), tibia 8.9 (7.82–8.37), metatarsus 9.92 (8.33–8.97), tarsus 1.99 (1.61–1.73), total 29.16 (25.04–26.9); II: 9.28 (8.15– 8.85), 1.02 (0.89–0.9), 12.12 (10.18–11.08), 13.75 (11.36–12.36), 2.04 (1.72–1.83), 38.21 (32.31–34.92); III: 7.3 (6.47–7.06), 0.95 (0.84–0.87), 7.75 (6.84–7.44), 10.37 (8.9–9.58), 1.68 (1.3–1.4), 28.05 (24.35–26.35); IV: 7.97 (6.86–7.48), 1.01 (0.8–0.89), 8.66 (7.56–8.26), 11.4 (9.62–10.44), 1.86 (1.49–1.58), 30.9 (26.33–28.65). Palp: femur 1.36 (1.17–1.26) long, 0.27 (0.24–0.27) wide; patella 0.45 (0.4–0.43) long, 0.28 (0.26–0.28) wide; tibia 0.65 (0.55–0.6) long, 0.4 (0.38–0.39) wide; tarsus 0.6 (0.5–0.6) long, 0.35 (0.32–0.42) wide. Ratio between the lengths of some segments of the leg I (and its total length) and carapace: femur 3 (2.8–3.1), tibia 3.7 (3.5–3.7) and leg I 12 (11.1–11.8) times as long as carapace. Ratio between length and width of palpal segments: femur 5 (4.3–5.2), patella 1.6 (1.5–1.6) and tibia 1.6 (1.3–1.5) times longer than wide, tarsus 1.7 (1.4–1.8) times longer than its basal width. Bulb suboval and slightly shorter than tarsus size. Embolus basally thick, with thickness decreasing towards the apex; its basal portion is slightly sinuous, the medial to distal part nearly straight and the tip is thin and downward curving; approximately 2.4 times longer than bulb length in retrolateral view, without carina, and inserted at the distal half of the bulb ( Figs 6–11 ). Palp and legs covered by long setae interspersed with shorter and thinner setae.

Total length: 5.65 (4.96–5.41). The measurements of selected body parts of all males of the type-series are provided at Table 1.

Description of females. Similar to males, except for the following characters:

Coloration. Carapace pale yellow, anterior half of pars cephalica and median groove slightly darkened (light orange). Inconspicuous moderate orange Y-mark posteriorly on pars cephalica ( Fig. 13 ). Chelicerae strong yellow (pale yellow in female III), darkened (strong reddish brown) in its distal part ( Fig. 16 ). Sternum pale yellow ( Fig. 15 ). Labium and endites strong yellow (pale yellow in female III), darkened (strong reddish brown) in their distal portion. Legs pale yellow (strong yellow in female II) with the extremities of each segment darkened (strong reddish brown). Palps pale yellow (strong yellow in female II), with the distal portion of tarsus strong yellow. Opisthosoma yellowish gray ( Fig. 12 ).

Prosoma. Carapace 2.92 (3–3.04) long, 2.37 (2.41–2.5) wide. Eye sizes and interdistances: ALE 0.06 (0.06– 0.07), PME 0.07 (0.07–0.09), PLE 0.07 (0.07–0.08), PME-PLE 0.44 (0.44–0.49), PME-ALE 0.34 (0.34–0.35), ALE-PLE 0.06 (0.06–0.07), PME interdistance 0.06. Clypeus 0.42 (0.36–0.48). Labium 0.64 (0.71–0.77) long, 0.65 (0.65–0.75) wide. Sternum 1.45 (1.33–1.53) long, 1.35 (1.29–1.46) wide.

Legs and palp. Leg formula II, IV, I, III. Legs length: leg I: femur 6.88 (7.4–7.7), patella 0.98 (0.99–1.07), tibia 7.44 (8.31–8.62), metatarsus 7.46 (8.55–8.81), tarsus 1.57 (1.65–1.81), total 24.33 (26.9–27.89); II: 7.98 (8.88– 9.09), 0.97 (1.03–1.09), 8.73 (9.99–10.27), 9.16 (10.95–11.16), 1.63 (1.76–1.9), 28.47 (32.61–33.34); III: 6.48 (7.04–7.3), 1.02 (1.01–1.08), 6.36 (6.93–7.21), 7.77 (8.73–8.93), 1.35 (1.46–1.57), 22.98 (25.18–25.91); IV: 7.07 (7.77–7.82), 1.01 (1.01–1.07), 7.27 (8.06–8.11), 8.98 (10.12–10.47), 1.56 (1.68–1.85), 25.89 (28.66–29.06). Palp: femur 1.48 (1.52–1.58) long, 0.22 (0.21–0.22) wide; patella 0.49 (0.44–0.48) long, 0.26 (0.26–0.29) wide; tibia 0.86 (0.96–0.98) long, 0.23 (0.21–0.23) wide; tarsus 1.49 (1.32–1.62) long, 0.17 (0.17–0.2) wide. Ratio between the lengths of some segments of the leg I (and its total length) and carapace: femur 2.36 (2.45–2.57), tibia 2.55 (2.75–2.86) and leg I 8.33 (8.91–9.3) times as long as carapace. Ratio between length and width of palpal segments: femur 6.6 (7.1–7.4), patella 1.9 (1.7–1.8), tibia 3.8 (4.3–4.7), tarsus 8.5 (7.7–8.8) times longer than wide; tarsus not incrassate.

Genitalia. Spermatheca with straight seminal receptacles connected by a thin and weakly sclerotized transversal plate ( Figs 17–20 ).

Total length: 6.36 (6.8–7.43). The measurements of selected body parts of all females of the type-series are provided at Table 1.

Figures

FIGURES 1–5. Loxosceles troglobia sp. nov. 1, habitus of male holotype; 2, carapace of male holotype, dorsal view; 3, carapace of male III, lateral view; 4, sternum of male holotype; 5, eyes, clypeus and chelicerae of male holotype. Scale bars: 1 mm (Fig. 1), 0.4 mm (Figs 2–5).

FIGURES 12–20. Loxosceles troglobia sp. nov. 12, habitus of female IV; 13, carapace of female IV, dorsal view; 14, carapace of female II, lateral view; 15, sternum of female IV; 16, eyes, clypeus and chelicerae of female IV; 17-20, spermathecae of females I–IV, respectively, ventral view. Scale bars: 1 mm (Figs 12, 17–20), 0.5 mm (Figs 13, 14), 0.4 mm (Figs 15, 16).

FIGURES 24–29. Live specimens of Loxosceles troglobia sp. nov. 24–25, adult males from Tapera d´água cave; 26, adult female from Tapera d´água cave; 27, adult female from Tabocas cave; 28, droplets of condensed water over an immature specimen in Tapera d´água cave; 29, cannibalism observed in Tapera d´água cave.

FIGURES 6–11. Loxosceles troglobia sp. nov. 6–8, left palp of male holotype: 6, dorsal view; 7, retrolateral view; 8, prolateral view; 9, prolateral view of right palp of male II (mirrored); 10, prolateral view of left palp of male III; 11, prolateral view of right palp of male IV (mirrored). Scale bars: 0.4 mm.