Loxosceles troglobia

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

publication ID

https://doi.org/10.11646/zootaxa.4438.3.9

publication LSID

lsid:zoobank.org:pub:7935D976-F058-47D5-B4CF-839AA0F94FF6

persistent identifier

http://treatment.plazi.org/id/CB1515BB-A0BE-4E4D-9C8A-BF40FA3789D9

taxon LSID

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

treatment provided by

Plazi

scientific name

Loxosceles troglobia
status

sp. nov.

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 213031View Materials), female I (ISLA 47465), female II ( ISLA 47466), female III ( IBSP 213032View Materials) and female IV (ISLA 47467), same date, locality and collector as the holotypeGoogleMaps  .

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.GoogleMaps 

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 View Figure , 13, 16 View Figure , 24 View Figure ). 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 View Figure , 12–14 View Figure , 24–30View FIGURES 24–29View FIGURE 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 View Figure ). 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 View Figure ). 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 View Figure ). Sternum pale yellow ( Fig. 4 View Figure ). Chelicerae ( Fig. 5 View Figure ), 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 View Figure ). 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 View Figure ).

Prosoma. Carapace 2.43 (2.26–2.37) long, 2.11 (1.98–2.08) wide. Eyes without pigment ( Fig. 2, 5 View Figure , 24 View Figure ). 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 View Figure , 24 View Figure ). Sternum, labium, chelicerae and endites covered by long setae interspersed with shorter and thinner setae ( Figs 4, 5 View Figure ).

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

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 View Figure ). 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 View Figure ). Chelicerae strong yellow (pale yellow in female III), darkened (strong reddish brown) in its distal part ( Fig. 16 View Figure ). Sternum pale yellow ( Fig. 15 View Figure ). 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 View Figure ).

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 View Figure ).

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.