Spelaeobochica mahnerti, Viana & Ferreira, 2020

Viana, Ana Clara M. & Ferreira, Rodrigo L., 2020, Spelaeobochica mahnerti, a new cave-dwelling pseudoscorpion from Brazil (Arachnida: Pseudoscorpiones: Bochicidae), with comments on the troglomorphism of the Brazilian bochicid species, Zootaxa 4731 (1), pp. 134-144 : 135-138

Spelaeobochica mahnerti sp. n.

( Figs 1–12 ; 18 , left)

Material examined. Holotype female (ISLA 50771), Brazil, Minas Gerais, Gruta Velha Nova, Monjolos (18º16ʹ36.2ʺS, 44º06ʹ07.9ʺW), 15 April 2017, leg. R. L. Ferreira . Paratype: male ( ISLA 50772), same details as holotype .

Etymology. The specific name is given in honor of Dr. Volker Mahnert (1943–2018), who contributed enormously to the knowledge of Brazilian cave-dwelling pseudoscorpions.

Diagnosis. Differing from the congeneric species by the following combination of characters: chelicera with 9−10 dorsal setae, rallum with 3 apically dentate blades (denticulation more pronounced on the distal blade, which is longer than other blades); palps slender (e.g. femur 6.5−6.6, patella 4.1, chela with pedicel 5.6−5.8 times longer than broad), femur with a small distinct tubercle on antiaxial side near distal end, patella with a small tubercle on dorsoparaxial side near the end of pedicel, trichobothrium ib in far distal half of hand dorsum (near the base of fixed finger), absence of accessory teeth on chelal fingers (or, more rarely, the presence of two antiaxial accessory teeth on the fixed chelal finger), venom apparatus present in both fingers; legs slender (e.g. leg IV: femur+patella 5.5–6.3, tibia 9.4−11.4, basitarsus 3.5−3.7, telotarsus 9.6−12.1 times longer than broad), arolia undivided and a little longer than claws, subterminal setae smooth.

Description of adults (female, followed by male in brackets, when different). Troglomorphic habitus ( Fig. 18 , left). Palps, carapace, chelicerae, coxae and first abdominal segments strong brown, other parts of the body vivid yellow. Tergites and sternites with evident sclerotization along the anterior margin. Vestitural setae smooth, delicate and long.

Carapace. 1.6 times longer than broad, broadest near middle, then slightly narrowed to base; anterior margin smoothly rounded, distinctly sclerotized; without epistome; a very shallow transverse furrow near posterior margin; surface scaly-reticulate; eyes absent; 38 [34] setae (6 on anterior margin and 4 on posterior margin); anterior margin with 10 acute microtubercles [14], and a few more scattered on the carapace.

Chelicera ( Fig. 1 ). Scaly-reticulate; with 9–10 [9] setae on hand; fixed finger with 8–10 rounded [8–9 slightly acute] teeth; movable finger with 11–13 rounded [8–9 slightly acute] teeth, the subterminal tooth large and laterally displaced; galea simple, slender and acute; tip of subgaleal seta almost reaches the tip of galea; serrula exterior with 26 [25–27] blades, serrula interior with 16–18 [19–20] blades (some blades missing in the middle portion); rallum ( Fig. 2 ) with 2–3 [3] apically dentate blades (middle blade probably missing in the left cheliceral rallum of the holo- type), denticulation more pronounced and abundant on the distal blade (which is longer than other blades; the latter almost equally-sized), the two distal blades closely set (when 3 blades are present).

Tergites. Undivided, scaly-reticulate; chaetotaxy I–XI 5: 6: 7: 9: 10: 9: 10: 10: 9: 7: 6 [5: 6: 7: 8: 9: 8: 9: 10: 10: 7: 6]. Lyrifissures present medially on tergites V−VIII: 2, 2, 2, 1 [lyrifissures present medially on tergites IV–IX: 2, 2, 2, 3, 2, 2]. Pleural membranes smoothly, longitudinally striate. Anal cone with one pair of small dorsal setae.

Coxae. Palpal: manducatory process acute, with 5 setae [4–5]: 2 apical marginal setae of unequal length (the distal one longer), 2 discal setae (both are long, but the distal one is slightly longer), and 1 shorter, more basal seta [right: 2 apical marginal setae of unequal length (the distal one shorter) and 2 discal setae (the distal one longer); left: same as holotype, except for the distal discal seta, which is broken]; palpal coxae scaly-reticulate, with several tiny pores, 13 setae [9]; leg coxae scaly-reticulate, with a small lyrifissure next to foramen margin, coxae I and II with some tiny pores on anterior region (II with less pores than I), coxae III and IV without pores; setae I 7–8, II 7, III 7–9, IV 9–11 [I 6, II 6–7, III 6–7, IV 9–10].

Genital operculum of male ( Fig. 3 ). 3 anterior setae and 17 posterior and median setae; surface scaly-reticulate; a pair of lyrifissures present anteriorly.

Male sternites: III with 11 anterior setae, 14 posterior setae and 2 suprastigmal setae on each site, IV with 7 posterior setae and 2 suprastigmal setae on each side, formula for V–XI: 9: 9: 9: 11: 12: 11: 6. Lyrifissures present medially on sternites IV–IX: 3, 2, 2, 2, 3, 1. Anal cone with one pair of small ventral setae. Surfaces scaly-reticulate.

Genital operculum of female ( Fig. 4 ). 11 setae situated on posterior margin of sternite II; surface scaly-reticulate; a pair of lyrifissures present anteriorly. Median and lateral cribrate plates not observed.

Female sternites. III with 19 posterior setae and 2 suprastigmal setae on each side, IV with 9 posterior setae and 2 suprastigmal setae on each side, formula for V–XI: 9: 9: 11: 12: 13: 12: 5. Lyrifissures present medially on sternites IV−IX: 2, 3, 2, 3, 2, 1. Anal cone with one pair of small ventral setae. Surfaces scaly-reticulate.

Palps ( Figs 5–9 ). Trochanter scaly-reticulate; femur ( Fig. 9 ) with a small distinct tubercle on antiaxial side near distal end, scaly-reticulate; patella ( Fig. 9 ) with a small tubercle on dorsoparaxial side near end of pedicel, mostly scaly-reticulate, except for antiaxial face; chelal hand mostly lightly scaly-reticulate, except for the dorsoparaxial face and most of the bases of fingers, which are finely granulate, pedicel distinctly scaly-reticulate. Fixed finger with 95–98 [70–74] acute, heterodentate, mostly contiguous teeth (sometimes irregularly spaced) ( Figs 6, 8 ); holotype with 2 small, antiaxially displaced proximal teeth on left fixed chelal finger ( Fig. 8 ). Movable finger with 97 [78–78] teeth, also acute, heterodentate, mostly contiguous ( Fig. 7 ). Venom apparatus well developed in both fingers; venom duct ( Fig. 5 ) extends along the distal third of both fingers in the right chela, and occupies the distal fourth of both fingers in the left chela [occupies the distal fourth only in the left movable finger]; on the left chela, nodus ramosus situated distally from ist and st (ca. 150 µm and 375 µm, respectively) [ca. 75 µm and 200 µm, respectively]; on the right chela, nodus ramosus situated distally from ist and st (ca. 110 µm and 125 µm) [ca. 25 µm and 75 µm]. Trichobothrial pattern ( Fig. 5 ): ib in far distal half of hand dorsum, near base of fixed finger; ist distal to est, est is slightly proximal to level of st on movable finger (except for the left fixed finger of the holotype, where est is slightly distal to level of st); isb almost equidistant to level of sb and esb; it slightly distal to et; b-sb-st-t almost equidistant.

Legs ( Figs 10–12 ). Leg IV ( Fig. 10 ): subterminal setae of tarsus smooth and acuminate ( Fig. 11 ); some tactile setae present; arolia undivided and a little longer than claws, latter smooth ( Fig. 11 ).

Measurements and proportions as in Table 1 .

Figures

FIGURE 18. Spelaeobochica mahnerti sp. n. and troglomorphisms in Spelaeobochica species. On the left, the male specimen (paratype) of S. mahnerti sp. n.; in the middle, a map of Brazil showing the different speleological units (red stars represent the locality of each species); on the right, from top to bottom, S. allodentatus, S. iuiu, S. goliath and S. muchmorei, respectively. Observe the increment in the degree of troglomorphism shown by Spelaeobochica species (greater appendage elongation) from northern to southern regions.

FIGURES 1‒4. Spelaeobochica mahnerti sp. n. 1, right chelicera of holotype, lateral (slightly ventral) view, scale bar 0.25 mm; 2, right cheliceral rallum of holotype, scale bar 0.075 mm; 3, male genital operculum and median portion of sternite III, scale bar 0.20 mm; 4, female genital operculum and median portion of sternite III, scale bar 0.20 mm.

FIGURES 5‒9. Spelaeobochica mahnerti sp. n. 5, left chela of paratype, showing trichobothrial pattern, nodus ramosus, with some teeth amplified (holotype), antiaxial view, scale bar 1 mm; 6, distal marginal teeth of the fixed finger amplified, scale bar 0.1875 mm; 7, distal marginal teeth of the movable finger amplified, scale bar 0.1875 mm; 8, marginal and antiaxial accessory teeth at the proximal region of the fixed finger amplified, scale bar 0.1875 mm; 9, left palp, minus chela, of holotype, dorsal view, scale bar 1 mm.

FIGURES 10‒12. Spelaeobochica mahnerti sp. n. 10, left leg IV of holotype, scale bar 1 mm; 11, distal end of telotarsus of left leg IV of holotype, scale bar 0.20 mm; 12, right leg I of holotype, scale bar 1 mm.