Cybella deharvengi, Judson, Mark L. I., 2017

Judson, Mark L. I., 2017, A new subfamily of Feaellidae (Arachnida, Chelonethi, Feaelloidea) from Southeast Asia, Zootaxa 4258 (1), pp. 1-33 : 5-14

Cybella deharvengi n. sp.

Figs 2–47

Diagnosis. See under Cybella bedosae n. sp.

Etymology. This species is named after Louis Deharveng (MNHN), who discovered the cavity in which the types were found and who has made many important contributions to our knowledge of soil and cave faunas in Southeast Asia.

Type material. Holotype ♂, Vietnam, Kien Giang, Kien Luong , Hon Chong , Nui Bai Voi (Mo So Lon), ‘grotte des Feaellidae’, 1013ʹ25.81ʺN 10436ʹ57.35ʺE, 32 m a.s.l., on wall of limestone cavity in near-total obscurity, 2 June 2008, leg. M. Judson ( MNHN Ps-704.43) . Paratypes: 3 ♂, 1 tritonymph, same details as holotype (2 ♂, MNHN Ps-704.44–45, and tritonymph, MNHN Ps-704.46; 1 ♂ deposited in Institute of Tropical Biology, Hanoi, Vietnam) .

Non-type material. 1 tritonymph, Vietnam: Kien Giang, Kien Luong, Hon Chong , Nui Bai Voi , near Grottehôpital de Mo So [=Hang Moi Chau or Hang Mo So], 1013ʹ31.6ʺN 10436ʹ59.2ʺE, 29 m a.s.l., 16 January 2003, litter, Berlese extraction, leg. Le Cong Man, collector’s code VIET-ManKG23 ( MNHN Ps-704.47). Tarsus of left leg I missing.

Description of male. Sclerotized parts amber-brown ( Fig. 2 ); body and appendages covered with finely granular cerotegument, apart from non-reticulate areas, such as the fingers of chelicerae and chelae. Vestitural setae very small and simple, only chelal fingers, chelicera and manducatory process with larger setae. Carapace ( Fig. 4 ) longer than broad, distinctly broadened proximally. Anterolateral corners truncate, not projecting anteriorly, median projections small, directed slightly towards midline, two raised mounds between eyes and an unpaired mound in middle of mesozone, behind which is a moderate ridge that is only weakly produced laterally. Two pairs of large eyes, with reflective tapeta. One pair of lyrifissures near eyes, one lateral pair behind posterior eyes, and 2– 5 posteriorly; one specimen with a single lyrifissure on mesozone (total number of lyrifissures 6–9). Carapace with about 37 setae (N = 1), of which 6 on posterior margin and 4 laterally on each side, below level of eyes ( Fig. 5 ).

Tergite I ( Fig. 4 ) distinctly shelved to allow posterior margin of carapace to pass over distal portion; posterior margin desclerotized; undivided medially, but flanked on each side by a small, sclerotized plate, each bearing 1 or 2 setae (no seta on main part of tergite I); lyrifissures absent. Membrane between tergites I and II extensive and rounded over posterior part of I. Tergites II–IX divided medially; setae per half-tergite 8: 10–11: 1 3–15: 13–15: 14–15: 14–16: 13–16: 12–14; tergite X undivided, with 21 setae. Segment XI with 10‒11 posterior setae plus 3 around anal mound (total 13‒14). Tergite XII with 2 setae. Tergite I without lyrifissures; half-tergite II with 1 anterolateral and 1 submedian lyrifissure; half-tergites III–IX with 1 anterolateral and 3–4 posterior lyrifissures; tergite X with a total of 5 lyrifissures.

Pleural membranes very broad, with two longitudinal folds ( Figs 3, 6 ) on each side; dorsal fold with setae on segments III–XI and lyrifissures on V‒VII; ventral fold with setae on segments VI–XI and lyrifissures on VIII–X; lyrifissures set in slight depressions in folds; simple gland pores opening ventrally on folds ( Fig. 3 ); pleural plates absent (only tiny areas of sclerotization around pores and areoles of setae).

Palp coxa elongate, almost as long as combined length of leg coxae I–IV ( Fig. 8 ). Manducatory process ( Fig. 13 ) with 1 small apical seta and a large subapical seta, both simple; another large seta is present at base of manducatory process. Clivus ( Figs 8‒9 ) well marked, but not projecting laterally. A single, normal lyrifissure behind foramen of palp coxa ( Fig. 9 ) (similar to position of posterior maxillary lyrifissure in Iocheirata). Median maxillary lyrifissure ( Fig. 10 ) circular, central disk porous; internal apodeme present and attached to muscle. Coxa I ( Fig. 12 ) with 1 primary and 8–15 secondary spines arranged around rim of pit. Coxa III with enlarged, irregular granules anteromedially ( Fig. 8 ). Setae of coxae: P ca 30, I 6‒7, II 7‒ 10, III 6‒8, IV 9‒14.

Anterior genital sternite ( Fig. 16 ) with 8 median setae and a pair of lyrifissures; posterior genital sternite with a median pair of lyrifissures, 9–11 median setae and a single pair of lateral setae (total 11–13). Sternites IV–X divided medially. Darkened bars weakly developed on sternites VI–VIII, stronger on IX. Denticulation on sternites VIII–XI (weak on VIII and XI). Setae of half-sternites (IV–X) 8–10: 8–10: 9: 9–11: 7–10: 6–9: 7; all setae posterior. Segment XI undivided, with 11 setae anteriad of anal opening. Sternite XII with 2 setae, closer together than those of tergite XII. Each half-sternite usually with 1 paraxial and 1 antiaxial lyrifissure, but occasionally with up to 4; segment XI with only antiaxial lyrifissures and a pair in front of anal opening.

Male genitalia ( Figs 14‒15 ) relatively simple; atrial plate weakly sclerotized and without strongly marked ornamentation, but with a distinct tubular pocket laterally ( Fig. 14 : inv); lateral sacs of moderate size, without an apical constriction; median sac reduced, but with a distinct sclerotized ring at end of duct ( Fig. 15 : sr); posterior wall of atrium with a small number of papillae ( Fig. 14 : pap) that are not associated with glands; posterior plate with 3–4 internal setae on each side, of which the posterior pair is enlarged and slightly spatulate. Mature, encysted spermatozoa (observed in vas deferens) with a maximum diameter of 4 µm.

Chelicera with reticulation ending fairly abruptly in a raised crest; palm with 5 large and 6–7 small setae; 2 lyrifissures on antiaxial face ( Fig. 17 ), 1 on paraxial face at base of fixed finger ( Fig. 21 ). Base of fixed finger concave on paraxial side. Movable finger with a single, large tooth subdistally ( Fig. 18 ). Spinneret short (18–23 µm) simple, tubular (not flattened), but flared at base ( Figs 18–20 ); 3 internal silk ducts, these lying side by side and thus only evident in ventral view. Serrula exterior ( Fig. 19 ) with 18–21 blades, arranged in an arc, plus a small, distally-directed apical process ( Fig. 18 ) (total 20–22). Serrula interior ( Fig. 21 ) with about 13–15 blades, basal blades enlarged and difficult to distinguish individually (counts based on internal canals). Rallum ( Figs 19, 21 ) with two long (anterior 26 µm, posterior 25 µm), simple blades, closely appressed and thus difficult to distinguish, tips blunt, but this is only evident when they are observed at high magnification; in close proximity to basal blade of serrula exterior. Galeal seta (gs) barely extending beyond tip of spinneret.

Palps of typical feaellid facies, femur very robust, patella and chela small ( Figs 23‒24 ). Trochanter with a strong, thick, dorso-ventrally flattened, anterodistal projection. Femur with a moderate anterobasal projection and a dorsobasal mound; reticulation becoming strongly raised anteriorly, producing a tooth-like appearance in dorsal view. Patella with 1 large and 1 small lyrifissure dorsally near base, and 1 small dorsal lyrifissure apically. Chela with reticulate cuticle extending onto base of fixed finger, but not raised distally. Fixed finger with 4 lyrifissures: 1 antiaxial and 1 paraxial at base; 1 antiaxial behind trichobothria eb and esb; 1 dorsal, just in front of trichobothrium it. Movable finger with 2 ventral lyrifissures, one near middle and the other just in front of trichobothrium t. Fixed finger with apodens plus 15–16 marginal, 7–9 paraxioventral, 5 paraxial and 1 tuberculate basal-paraxial tooth (total 29–31). Tuberculate tooth of fixed finger with an ordinary seta at base ( Fig. 26 ), that of movable finger with a seta nearby, but not on tubercle ( Fig. 28 ). Tuberculate tooth of movable finger in a more distal position relative to that of fixed finger ( Fig. 29 ). Fixed finger with a minute dorsal seta near apex ( Fig. 25 ), movable finger with a similar seta ventrally near apex ( Figs 27, 33 ), these perhaps representing the lamina defensor of other pseudoscorpions. Movable finger weakly S-shaped in ventral view; with 1 apical, 18‒20 marginal (almost aligned), 5‒8 paraxial and 1 basal tuberculate tooth (total 27–28). Sensillum af 1 in dorsal position, slightly closer to dx than to it. Movable finger with coupled sensilla (pc) above trichobothrium b ( Figs 30‒31 ); sensillum am 1 slightly behind tip, in dorso-antiaxial position; a small pore or sensillum is also present ventrally, immediately in front of trichobothrium t ( Fig. 33 ). Fixed chelal finger with 13 chemosensory setae in antiaxial row. Movable finger with 13–14 bacilliform setae (20–24 µm long) in pit ( Figs 30, 34 ); walls of pit finely granular (probably due to a thin lining of exocuticle). Trichobothria typical; sb and t of movable finger situated on ventral face, sb level with posterior rim of pit containing chemosensory setae. Hair of trichobothrium x 2 thicker than that of x 1 and abruptly curved at tip; tip of x 1 blunt (very slightly bulbous).

Legs with reticulate-scaly ornamentation; very few gland pores present. Setae generally short and strongly curved, but those of ventral faces longer. Femur of leg I with a large, oblique, paraxio-basal lyrifissure. Patella of legs I–IV with a dorsal lyrifissure orientated parallel to long axis and set in a depression. Trochanters of legs III and IV with a small posterodorsal spur just beyond pedicel; trochanters inflated, with maximum diameter oblique to dorso-ventral axis. Tarsus of leg I (but not other legs) with slight torsion distally, dorsal face orientated slightly anteriorly. Subterminal setae not obviously differentiated from other setae. Arolia simple, broad, distinctly shorter than claws; claws simple, not broadened distally ( Figs 42‒43 ).

Measurements (in mm, standard ratios in parentheses). Body 1.8×1.2–1.3. Carapace 0.546–0.619×0.433–0.447 (1.3–1.4). Chelicera 0.202–0.247×0.128–0.154 (1.6), palm 0.132–0.175 (1.1), movable finger 0.095–0.114 (0.65×palm), spinneret 0.018–0.023. Palp femur 0.493–0.522×0.264–0.281 (1.8–2.1), patella 0.396–0.414×0.155– 0.172 (2.4–2.6), chela 0.555–0.571×0.126–0.132 (4.3–4.5), palm 0.142–0.148 (1.1–1.2), movable finger 0.401– 0.413 (2.5–2.9). Chelicera 0.247×0.154 (1.6), palm 0.175 (1.1), movable finger 0.114 (0.65). Leg I (N=3) trochanter 0.150×0.110 (1.4), femur 0.211–0.223×0.075–0.81 (2.7–2.8), patella 0.178–0.194×0.088–0.092 (2.0– 2.1), tibia 0.165–0.190×0.063–0.068 (2.6–3.0), tarsus 0.256–0.263×0.053–0.054 (4.8–4.9). Leg III (N=1) trochanter 0.196×0.112 (1.7), femur 0.212×0.088 (2.4), patella 0.247×0.103 (2.4), tibia 0.220×0.070 (3.2), tarsus 0.326×0.056 (5.9). Leg IV (N=3) trochanter 0.251–0.264×0.126–0.135 (1.9–2.0), femur 0.161–0.188×0.075–0.088 (2.0–2.2), patella 0.256–0.275×0.094–0.108 (2.4–2.7), tibia 0.337–0.361×0.059–0.066 (5.1–6.0), tarsus 0.325– 0.386×0.048–0.055 (6.8‒7.2).

Description of tritonymph. Generally similar to adult and almost of same size, but less sclerotized and thus lighter in colour. Carapace with untanned dorsolateral lines running along its length, giving the impression that the carapace is divided into three plates (one dorsal and two lateral); posterior depression less marked than in adult. Anterolateral plates less sclerotized than in adult and hence less evident. Chelicera ( Fig. 44 ) with 5 large and 5 small setae on palm; galeal seta 0.78 from base; spinneret ( Fig. 45 ) distinctly longer than in male, tubular and gently curved ventrally, base flared in dorsoventral view, but not in lateral view; rallum with two blades (anterior 23 µm, posterior 22 µm long), as in adult; serrula exterior with 19 blades plus anteriorly-directed process, distal 3 blades; serrula interior obscured. Fixed finger of chela with apodens plus 18 marginal teeth, 6 paraxial teeth and a basal tuberculate tooth (total 26), movable finger with apodens plus 17 teeth in slightly irregular marginal row, 7 paraxial teeth and basal tuberculate tooth (total 26). Movable finger with 13 bacilliform chemosensory setae in pit ( Fig. 47 ), surface of pit granular on left chela, but not on right chela. Trichobothria as in adult, except isb and sb absent ( Fig. 46 ).

Measurements of paratype tritonymph (in mm, standard ratios in parentheses). Body 1.80×1.1 (1.5). Carapace 0.533×0.416 (1.3). Chelicera 0.182×0.119 (1.5), palm 0.136 (1.15), movable finger 0.087 (0.64). Palp femur 0.459×0.241 (1.9), patella 0.355×0.149 (2.4), chela 0.539×0.126 (4.3), palm 0.138 (1.1), movable finger 0.378 (2.8). Leg I femur 0.192×0.070 (2.8), patella 0.167×0.081 (2.1), tibia 0.159×0.059 (2.7), tarsus 0.234×0.051 (4.6). Leg IV trochanter 0.232×0.121 (1.9), femur 0.161×0.075 (2.1), patella 0.242×0.095 (2.5), tibia 0.304×0.095 (3.2), tarsus 0.344×0.055 (6.3).

Measurements of smaller (non-type) tritonymph (in mm, standard ratios in parentheses). Body 1.48×0.96 (1.5). Carapace 0.463×0.370 (1.3). Palp femur 0.394×0.203 (1.9), patella 0.310×0.136 (2.3), chela 0.501×0.110 (4.6), palm 0.122 (1.1), movable finger 0.0.34 (2.8).

Remarks. The cavity in which the types were found was accessible by a vertical opening that was just sufficient for a person to slide through. The feaellids were found on a small, exposed surface (no more than 1 m 2) on a wall facing away from the entrance. This surface differed from the rest of the wall in having a pocked appearance and a dark, rust-like colour ( Fig. 1 ), presumably due to a metal oxide. It was humid, but not wet. The rest of the walls of the cavity, most of which were wet, were not found to have feaellids on them. The pseudoscorpions were near the entrance and would have been in permanent obscurity, but not total darkness. The floor of the cavity consisted of compact clay-soil, unsuitable for pseudoscorpions. The collecting details accompanying the non-type tritonymph from leaf litter do not specify whether it came from a cavity or a truly epigean habitat. However, given the large number of litter samples made by Le Cong Man, L. Deharveng and A. Bedos at Nui Bai Voi, it seems likely that this species has a preference for cavities or caves.

The identification of the non-type tritonymph is discussed below. The collection details for this specimen suggest that it was found in an epigean habitat, although the possibility that it came from one of the many cavities around the Grotte-hôpital cannot be excluded. Sifting of litter (by the author) and Berlese extractions of litter outside the cavity (by Louis Deharveng and Anne Bedos) did not produced any other feaellids.

Figures

FIGURES 1 ‒ 2. Cybella deharvengi n. sp. 1, area of cavity wall on which the types were found (photograph L. Deharveng); 2, habitus of male, dorsal view.

FIGURES 3 ‒ 7. Cybella deharvengi n. sp., male. 3, pleurum at level of segments VIII ‒ X, ventral view; 4, carapace and anterior tergites, dorsal view; 5, carapace, lateral view; 6, opisthosoma, anterior view, prosoma removed; 7, lateral tergal plate of segment I, seen in same orientation as Fig. 6. Abbreviations: den, denticulate ornamentation; gp, gland pore; ly, lyrifissure; s, setae; T ‒ II, tergite II. Scale lines 0.2 mm (Figs 1 ‒ 6), 0.05 mm (Fig. 7).

FIGURES 8 ‒ 13. Cybella deharvengi n. sp., male. 8, coxae, ventral view; 9, left palp coxa, lateral view; 10, median maxillary lyrifissure; 11, right coxae II ‒ IV, dorsal (internal) view; 12, median part of coxae I, showing pit and coxal spines; 13, manducatory process of right palp coxa, ventral view. Abbreviations: cliv, clivus; fbII, border of internal foramen of coxa II, fbIII, border of internal foramen of coxa III, fbIƑ, border of internal foramen of coxa IV, k, condyle; pcs, primary coxal spine; pmIII, posterior margin of coxa III. Scale lines: 0.2 mm (Fig. 9) 0.1 mm (Figs 11 ‒ 12), 0.05 mm (Figs 10, 13), 0.03 mm (Fig. 10).

FIGURES 14 ‒ 16. Cybella deharvengi n. sp., male. 14, genitalia, ventral view; 15, posterior genital plate, ventral view 16 right side of opisthosomal segments II ‒ V, ventral view. Abbreviations: apl, atrial plate; da, dorsal apodeme; dpdg, ducts of posterior dorsal gland; ejca, ejaculatory canal atrium; gp, gland pore; inv, invagination at side of atrial plate; lgs, lateral genital sac; ly, lyrifissure; mgs, median genital sac; pap, papilla on atrial wall; sp, spiracle; sps, spatulate seta; sr, sclerotized ring. Scale lines: 0.1 mm (Figs 14, 16), 0.05 mm (Fig. 15).

FIGURES 17 ‒ 22. Cybella deharvengi n. sp., male, left chelicera. 17, whole chelicera, antiaxial view; 18, tip of movable finger, antiaxial view; 19, distal part of chelicera, ventral view; 20, spinneret, ventral view; 21, distal part of chelicera (movable finger omitted), paraxial view; 22, chelicera in posterior view (dorsal at top, paraxial side to left). Abbreviations: ds, ducts of serrula interior; f, foramen; gs, galeal seta; ly, lyrifissure; pr, distal process of serrula exterior; r, rallum; s. ext, serrula exterior; s. int., serrula interior. Other abbreviations (b, es, gs, is, ls, sb) are designations of setae. Scale lines 0.05 mm (Figs 18 ‒ 20 share same scale line).

FIGURES 23 ‒ 34. Cybella deharvengi n. sp., male right palp. 23, chela, dorsal view; 24, palp minus chela, dorsal view (reticulate ornamentation drawn in part on femur); 25, tip of fixed chelal finger, dorsal view; 26, basal tuberculate tooth of fixed finger, dorsal view (relative to chela); 27, tip of movable chelal finger, paraxial view; 28, basal tuberculate tooth of movable chelal finger, ventral view (relative to chela), distal end to left; 29, chela, paraxial view (setae omitted); 30, chela, antiaxial view; 31, coupled sensilla; 32, distal sensillum; 33, distal end of movable finger, ventral view; 34, grouped chemosensory setae, antiaxial view. Abbreviations: af, apical sensillum of fixed finger; am 1, apical sensilla of movable finger; dx, duplex trichobothria; ld, probable lamina defensor; ly, lyrifissure; pc, coupled sensilla. Other abbreviations (eb, esb, est, et, ib, isb, ist, it, b, sb, st, t) are standard designations of trichobothria. Scale lines: 0.2 mm (Figs 23 ‒ 24, 29), 0.1 mm (Fig. 30), 0.05 mm (Figs 25 ‒ 28, 33 ‒ 34), 0.01 mm (Figs 31 ‒ 32).

FIGURES 35 ‒ 43. Cybella deharvengi n. sp., male right legs. 35, leg I, antiaxial view; 36, trochanter and femur of leg I, dorsal view; 37, trochanter and femur of leg I, paraxial view; 38, leg IV, antiaxial view; 39, patella of leg I, dorsal view; 40, patella of leg IV, dorsal view; 41, leg III, antiaxial view; 42, arolium of leg III, ventral; 43 apotele of leg I, antiaxial view. Abbreviations: ly, lyrifissure;. Scale lines 0.2 mm (Figs 35 ‒ 41), 0.05 (Figs 42 ‒ 43).

FIGURES 44 ‒ 47. Cybella deharvengi n. sp., paratype tritonymph. 44, chelicera, antiaxial view; 45, tip of movable cheliceral finger, antiaxial view; 46, right chela, antiaxial view; 47 grouped chemosensory setae, antiaxial view. Abbreviations: am 1, apical sensillum of movable finger; pr, distal process of serrula exterior; pc, coupled sensilla. Scale lines 0.1 mm (Figs 44, 46), 0.05 mm (Fig. 45), 0.02 mm (Fig. 47).