Spelaeobochica goliath, Viana & Souza & Ferreira, 2018

Viana, Ana Clara M., Souza, Maysa F. V. R. & Ferreira, Rodrigo L., 2018, Spelaeobochica goliath (Arachnida: Pseudoscorpiones: Bochicidae), a new troglobitic pseudoscorpion from Brazil, Zootaxa 4402 (3), pp. 585-594 : 586-592

Spelaeobochica goliath sp. n.

( Figs 1‒14 , 21 )

Material examined. Holotype male ( ISLA 46634) , Brazil , Minas Gerais, Lapa do Baianinho cave, Ibiracatu (15°45ʹ56.2ʺS, 44°14ʹ02.9ʺW), 20 January 2015, leg. R. L. Ferreira. Paratypes: 5 females (ISLA 46635‒46639), 1 deutonymph ( ISLA 46640), same details as holotype .

Etymology. The specific name goliath is the anglicized form of the Hebrew Golyath and is treated as a noun in apposition; it refers to the biblical figure Goliath, a giant Philistine warrior. It alludes to the size of the new species, which is the largest known Spelaeobochica .

Diagnosis. This new species presents the main characters found in the genus Spelaeobochica : eyes absent, rallum of 4‒6 dentate blades, pedipalps slender, femur with a tubercle present on lateral side near distal end, accessory teeth present on both palpal fingers, legs slender. It differs from the other members of genus Spelaeobochica by the following combination of characters: pedipalps finely granulate, scaly-reticulate, elongate (femur 11.2‒12.0, patella 7.6‒8.8, chela 7.9‒8.9 times longer than broad); small tooth-like protuberances present on femur and patella; a tooth-like protuberance present on paraxial side of chelal hand near base of fixed finger; anterior margin of carapace with a slight angular shape or, more rarely, smoothly rounded; trichobothrium est distal with respect to st on movable finger; isb much nearer to level of sb than to that of esb.

Description of adults (male, followed by female in parentheses, when different). Troglomorphic habitus ( Figs 1‒2 , 21 ). Pedipalps, carapace, chelicerae, coxae and first tergites reddish brown; other parts of body yellowish brown. Tergites and sternites lightly sclerotized along anterior margin. Vestitural setae smooth, delicate, and long.

Carapace. 1.8 (1.7) times longer than broad, broadest at level of leg I, then slightly narrowed to base; anterior margin with a slight angular shape (more rarely, smoothly rounded) ( Fig. 3 ); without epistome; surface scalyreticulate, with a broad reticulate transverse band near posterior margin where the reticulation is denser; a weak, laterodorsal, transverse depression also present near posterior margin; eyes absent; 77 setae (9 on anterior margin and 9 on posterior margin) (71‒84); anterior margin with 7 (6‒8) acute microtubercles, and a few more scattered on the carapace.

Chelicera ( Fig. 4 ). Scaly-reticulate; with 11 (11‒13) dorsal and 3 lateroventral setae on hand; fixed finger with 11 (11‒15) teeth, the 4 distal ones larger (second tooth minute in ♀ paratype 4, the 5 distal ones larger in ♀ paratype 1); movable finger with 5 (4‒5) acute teeth, the most proximal one minute in comparison to other teeth, third proximal tooth bifurcate, and a laterally displaced subterminal tooth, contiguous with the other teeth (bifurcation present on this tooth in female paratype 2); galea simple, slender and acute; tip of subgaleal seta reaching past tip of galea; serrula exterior with 32 (32‒33) blades, serrula interior with 23 (22‒25) blades; rallum ( Fig. 7 ) with 4 apically denticulate blades (denticulation more pronounced on distal blade), distal blade longer than other blades and with 5 (4‒5) terminal denticles (the first and last slightly longer), the two distal blades closely set.

Tergites. Undivided, scaly-reticulate; chaetotaxy I‒XI 7: 7: 9: 11: 12: 11: 14: 13: 13: 11: 6 (6‒7: 6‒8: 9‒11: 11‒12: 11‒14: 11‒12: 11‒13: 13‒16: 12‒15: 10‒12: 5‒7). Anal cone with one pair of small dorsal setae. Pleural membranes smoothly, longitudinally striate.

Coxae. Manducatory process acute, with 6 setae (some paratypes with 5 setae on one side and 6 on the other): 2 apical marginal setae of unequal length (the distal one longer), 2 discal setae (both long, but distal one slightly longer), and 2 short basal setae; palpal coxae scaly-reticulate, with several tiny pores, 12 (10‒14) setae (those of manducatory process not included); leg coxae scaly-reticulate, with a small lyrifissure next to foramen margin, several tiny pores present (number decreases from I to IV), setae I 8 (6‒9), II 6‒7 (4‒7), III 7‒8 (6‒8), IV 11 (10‒ 13).

Genital operculum of male ( Fig. 5 ). Scaly-reticulate; with 12 anterior setae and 23 posterior and median setae, a pair of lyrifissures present anteriorly.

Male sternites. III with 10 anterior setae, 13 posterior setae and 3 suprastigmal setae on each site, IV with 11 posterior setae and 2 suprastigmal setae on each side, formula for V‒XI: 12: 14: 13: 13: 11: 13: 6. Anal cone with 1 pair of small ventral setae. Sternites III‒IX with 2‒4 medial lyrifissures; one lyrifissure present on each side of anterolateral zone of sternites V‒XI.

Genital operculum of female ( Fig. 6 ). Scaly-reticulate; with 8‒14 marginal setae, a pair of lyrifissures present anteriorly (female paratypes 3 and 4 have only one lyrifissure); central genital structure of female sclerotized, with a median finger-like prolongation; lateral cribrate plates not observed.

Female sternites. Scaly-reticulate; III with 16‒20 posterior setae and 3 suprastigmal setae on each side, IV with 10‒12 posterior setae and 2 suprastigmal setae on each side, formula for V‒XI 13‒14: 13‒15: 13‒15: 12‒ 15: 13‒15: 11‒14: 6‒7. Anal cone with 1 pair of small ventral setae. A pair of lyrifissures present medially on sternites III‒IX (except for sternites V, VI, VIII and X in paratype 4, which have 3, 3, 3 and 1 lyrifissure; sternites V and VII presenting 3 lyrifissures in paratype 5); one lyrifissure present on each side of anterolateral zone of sternites V‒XI.

Pedipalp ( Figs 8‒10, 13 ). Trochanter finely granulate and scaly-reticulate; femur with a weak tubercle on antiaxial side near distal end ( Fig. 8 , arrowed), finely granulate and scaly-reticulate, with a series of small toothlike protuberances; patella with a tubercle on paraxial side near end of pedicel ( Fig. 8 , arrowed), finely granulate and scaly-reticulate, covered with small tooth-like protuberances; hand with pedicel scaly-reticulate, a tooth-like protuberance on paraxial side near base of fixed finger ( Fig. 10 , arrowed). Fixed finger with 103 (102‒116) teeth, arranged in three rows: 69 (69‒81) ordinary, acute, mostly contiguous teeth (sometimes irregularly spaced); paraxial row of 25 (22‒28) accessory teeth; antiaxial row of 9 (7‒11) accessory teeth, located in distal half. Movable finger with 109 (105‒118) teeth, arranged in three rows ( Fig. 13 ): 78 (78‒87) ordinary, acute, mostly contiguous teeth (sometimes irregularly spaced); paraxial row of 21 (20‒24) accessory teeth; antiaxial row of 10 (7‒11) accessory teeth, located in distal half. Paraxial accessory teeth of both fingers slightly larger than the ordinary and antiaxial accessory teeth. Venom apparatus well developed in both fingers, venom duct extends along the distal fourth of both fingers, nodus ramosus distal to ist and st (about 60 µm from ist and about 300 µm from st). Trichobothria ( Fig. 9 ): ib in distal half of hand dorsum; ist distal to est; est distal to level of st on movable finger; isb much nearer to level of sb than to that of esb; it indistinctly distal to et; b-sb-st-t almost equidistant.

Leg I ( Fig. 11 ). Surface scaly-reticulate.

Leg IV ( Figs 12, 14 ). Surface scaly-reticulate. Subterminal setae of tarsus finely dentate apically; some tactile setae present; arolia undivided and shorter than claws, latter smooth.

Measurements and proportions of all specimens as in Table 1.

Description of deutonymph. Paler than adult (whitish), with fingers of pedipalps and chelicerae light red. Vestitural setae smooth, delicate, and long.

Carapace. 1.5 times longer than broad; surface slightly scaly-reticulate; with 35 setae (6 on anterior margin and 5 on posterior margin).

Chelicera. Slightly scaly-reticulate; with 7 dorsal setae and 1 lateroventral seta on hand; fixed finger with 9 acute teeth; movable finger with 4 acute teeth, the first and fourth teeth smaller than the others, and a laterally displaced subterminal tooth, contiguous with the remaining teeth; galea simple, slender and acute; tip of subgaleal seta not reaching past tip of galea; serrula exterior with 22 blades, serrula interior with 16 blades; rallum of 4 apically denticulate blades (denticulation is more pronounced on distal blade), distal blade longer than the others and with 5 small terminal denticulations (first and last slightly longer), the two distal blades closely set.

Tergites. Slightly scaly-reticulate; chaetotaxy I‒XI 4: 4: 6: 6: 7: 8: 7: 7: 8: 8: 4. Anal cone with 1 pair of small dorsal setae. Pleural membranes smoothly, longitudinally striate.

Coxae. Manducatory process acute, with 4 setae: 2 apical marginal setae of unequal sizes (distal one longer), 1 long discal seta, and 1 shorter, more basal seta; palpal coxae slightly scaly-reticulate (different from adults), with several tiny pores, 6 setae (those of manducatory process not included); leg coxae with several tiny pores (number decreases from I to IV), coxae I‒IV with 4, 4, 3 and 4 setae, respectively.

Sternites. Slightly scaly-reticulate; chaetotaxy: 1: 6: 9: 8: 8: 7: 7: 7: 8: 3. Anal cone with 1 pair of small ventral setae.

Pedipalps. Trochanter finely granulate and scaly-reticulate (less granulate and less reticulate than adult); femur with a weak tubercle on antiaxial side near distal end, slightly granulate and scaly-reticulate, tooth-like protuberances absent; patella with a slight tubercle (less pronounced than in adults) on paraxial side near end of pedicel, slightly granulate and scaly-reticulate, without tooth-like protuberances; hand with pedicel slightly scalyreticulate; as in adults, a tooth-like protuberance is present on paraxial side near base of fixed finger. Trichobothria st, sb, esb, and isb absent. Fixed finger with 38 teeth, including a paraxial row of 7 accessory teeth. Movable finger with 37 teeth, including a paraxial row of 4 accessory teeth. Antiaxial accessory teeth absent on both fingers.

Leg I. Surface slightly scaly-reticulate. Division between basitarsus and telotarsus less visible than in adults.

Leg IV. Surface slightly scaly-reticulate. Division between basitarsus and telotarsus less visible than in adults. Subterminal setae finely dentate apically (similar to those of adults); some tactile setae present; arolia undivided and shorter than claws, latter smooth.

Measurements and proportions as in Table 1.

Habitat. Baianinho cave is a single-conduit cave presenting around 600 meters of horizontal projection ( Fig. 20 ). It has a single entrance and is a predominantly dry cave, especially the first 220 meters from the entrance ( Fig. 18 ). From this point on, a constriction of the cave conduit causes the innermost part of the cave to be more isolated and consequently more humid. Specimens of S. goliath sp. n. were only observed in this moister (and deeper) part of the cave. A total of 32 specimens was observed in a single afternoon, thus indicating the considerable size of their population ( Fig. 19 ). However, given the endemicity of this species and the lack of information about its population status, we decided not to collect all the observed specimens. It is noteworthy that all other species of Spelaeobochica appear to occur in low densities, it being extremely rare to observe more than one or two specimens in a single visit to the caves in which they occur (R.L. Ferreira, unpubl. obs.). Hence, the number of observed specimens in Baianinho cave is quite unusual for the genus, and is probably related to the huge amount of potential prey available, especially immature crickets of the genus Endecous Saussure, 1878 , which are widespread and abundant in the deeper portion of the cave. The crickets, in turn, feed on bat guano, which forms the main organic resource in the cave.

Adults of S. goliath sp. n. were mainly found walking on the surface of rocks or speleothems, while the immatures were more commonly observed under rocks, seemingly sheltering themselves. Given the apparent climatic stability of the deeper portion of the cave (where they were observed), this sheltering behavior could represent protection against predators (especially spiders) or a more specific microclimate requirement of the immatures, or both. Reboleira et al. (2010) also observed spatial segregation between adults and nymphs of Titanobochica magna , stating that the adults were always found in deep portions of the caves, whereas the nymphs were collected in galleries closer to the surface, with a high accumulation of organic matter.

Figures

FIGURES 1–2. Spelaeobochica goliath sp. n. 1, habitus of female; 2, habitus of male.Scale bar 5 mm.

FIGURES 3–7. Spelaeobochica goliath sp. n. 3, detail of male carapace, arrow points to the slightly prominent tip of the medial portion ofthe anterior margin, scalebar 0.10 mm; 4, lateroventralview of left chelicera of female,scale bar 0.25 mm; 5, genital operculum and median portion of sternite III of male, scale bar 0.15 mm; 6, genital operculum and median portion of sternite III of female, scale bar 0.15 mm; 7, rallum of left chelicera of female, scale bar 0.075 mm.

FIGURES8–14. Spelaeobochica goliathsp.n.8,leftpedipalp offemale,arrows point tolateral tubercles of femur and patella, scale bar 1 mm; 9, left chela of female, showing trichobothrial pattern and part of dentition (three rows of teeth overlapping), scale bar 1 mm; 10, ventral view of right chela of male, arrow points to tooth-like protuberance on paraxial side near base of fixed finger, scalebar 1 mm;11, left leg I of male, scalebar 1 mm;12, detail of telotarsus of leg IVof male, scalebar 0.15 mm; 13, antiaxiodorsal view of part of movable finger of left chela of female, showing the three rows of teeth, scale bar 0.20 mm; 14, left leg IV of male, scale bar 1 mm.

FIGURES 15–21. Distribution and habitat of Spelaeobochica goliath sp. n. 15, map of South America with Brazil and Minas Gerais state highlighted; 16, map of Minas Gerais state showing placement of the Bambuí Group and the municipality of Ibiracatu; 17, karstic landscape in the region of Ibiracatu; 18, aspect of the single entrance of Lapa do Baianinho cave; 19, sketch of Lapa do Baianinho cave, showing distribution of the specimens (red dots) observed during sampling; 20, inner portion of Lapa do Baianinho cave; 21, live specimen in its natural habitat.