Gymnobisium capense, Neethling & Neethling, 2023

Neethling, J. A. & Neethling, C., 2023, A systematic revision of the South African Gymnobisiidae (Pseudoscorpiones: Neobisioidea), Zootaxa 5256 (6), pp. 501-543 : 508-512

Gymnobisium capense sp. nov.

Figs 5–7

Holotype: ♀, SOUTH AFRICA, Western Cape, Rheenendal, Jubilee Creek Nature Reserve, 33°53′S, 22°58′E, 308m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling & C. Neethling, 7.XII.2015 ( NMBAP 00336 ).

Paratypes: 4♀, 4♂, Same data as holotype ( NMBAP 00337 ) .

Etymology. The Latin adjective capēnse means to belong to, or be from, the Cape Province in South Africa. The name refers to the main geographic distribution of this species.

Diagnosis. Large species (chela length ♀ 1.83–1.90 mm, ♂ 1.59 –1.74 mm), with chelae significantly more bulbous in females than in males (chela ratio ♀ 2.96–3.16 versus ♂ 3.70 –3.88 times longer than broad); fixed finger multi-toothed structure with seven strongly sclerotized teeth; cheliceral hand with six setae; galea with six rami; rallum with seven to eight blades, distal blades split apically. Differs from all congeners, except Gymnobisium inukshuk , by the presence of an extra basal seta on each chelicera. Differs from G. inukshuk by the presence of two pairs of well-developed eyes.

Description

Carapace: Somewhat broader than long, subquadrate, overall smooth and without furrow. Dark brown in females, lighter in males. Two pairs of eyes located dorso-laterally at the front ( Fig. 5A, C ). Small seta located on the dorso-anterior margin of each of the posterior eyes. Female carapace with 27, male carapace with 28 setae, arranged 4: 6: 2: 6: 9(10).

Abdomen: Tergites and sternites smooth, undivided and uniseriate. Female abdominal tergites uniformly dark brown. Male tergites same colour as carapace anteriorly and gradually darken posteriorly. Male tergites VIII–X often have a significantly darker central band ( Fig. 5A, C ). In both sexes the lateral and posterior edges of tergites I–XI are distinctly lighter in colour, tergite XII uniformly lighter in colour. The tergal setae are located on the posterior edge of each tergite, within the lighter coloured band. In both sexes sternites lighten in colour moving from posterior to anterior of abdomen ( Fig. 5B, D ). In females the sternites lighten in colour from dark brown (same colour as tergites) to light or transparent brown, and in males they lighten from dark brown to tan. Sternites I and II are fused and hardly distinguishable. Female operculum with 14 setae, eight along the posterior margin and six additional setae clustered loosely alongside, near the centre. Males with 27 setae at the operculum cluster. Pleural membrane cream to light yellow in colour, faintly papillate.

Tergal chaetotaxy: 7(8): 9(10): 10(12): 11(11): 12(12): 12(12): 11(12): 12(12): 11(11): 9(9): 11(12): 2(2). Sternal chaetotaxy: 14(27):?(?): 21(24): 21(16): 21(19): 19(16): 19(18): 17(15): 14(14): 13(13): 11(12): 2(2).

Pedipalp: All segments smooth and coloured orange-brown in both sexes. Trochanter cone-shaped and rounded anteriorly, curved slightly posteriorly. Base narrow, widening distally. Setae present on the anterior surface. Femur slender, 3.70–3.79 (♀) to 3.86–3.95 (♂) times longer than wide, somewhat constricted basally, widening just distal of base. Shallow disto-prolateral excavation present. Setae absent from base, though distributed evenly over rest of surface. Patella constricted and slightly angled at base, widening markedly distal at around a quarter segment length, 2.57–2.75 (♀) to 2.85–2.92 (♂) times longer than wide. Several small lyriform fissures present on the dorsal surface, just distal of base. Two larger lyriform fissures present latero-dorsally from these, where the segment starts to widen. Deep disto-prolateral excavation present. Setae sparse at base, more numerous on wide part of patella ( Fig. 7B ).

Chela: In both sexes smooth and uniformly orange-brown, fingers may be slightly darker. Female hand bulbous, strongly convex on the prolateral edge, slightly less so on the retrolateral edge ( Fig. 6A, B ). Male hand smaller, markedly less convex prolaterally ( Fig. 6C, D ). Pedicel short in both sexes, retrolateral condyle small but distinct and rounded. Fingers narrow, same length as hand (with pedicel) and curved slightly prolaterally. Fixed and movable chelal fingers with eight and four trichobothria respectively ( Fig. 7A ).

Terminal multi-toothed structure of fixed finger extends beyond venom tooth of movable finger in both sexes, structure of female thicker, bent acutely downward ( Fig. 7E ), more slender and less bent in males ( Fig. 7F ). In both sexes, structure contains seven strongly sclerotized teeth; front tooth not significantly larger than tooth just behind it; five teeth in line behind front tooth, raised and slightly prolateral, most distal tooth expanded, reaching beyond front tooth; single large tooth on retrolateral surface, behind raised teeth. Both fingers with rounded, juxtadentate teeth situated on flexible lamellae. Lamella on fixed finger originating roughly one quarter finger length from base, on movable finger roughly one third finger length from base. Female fixed finger with 63–65 lightly sclerotized, juxtadentate teeth, 15–16 proximal to lamella base, together with seven strongly sclerotized teeth on distal structure. Male fixed finger with 63–66 lightly sclerotized, juxtadentate teeth, 19–20 proximal to lamella base, together with seven strongly sclerotized teeth on distal structure. Female movable finger with 54–57 lightly sclerotized, juxtadentate teeth, 19–20 proximal to lamella base. Male movable finger with 61–64 lightly sclerotized, juxtadentate teeth, 27–29 proximal to lamella base. Two thickened, spine-like setae present on distal end of movable finger in both sexes.

Chelicera: Hand with six long and acuminate setae, es shorter, two basal setae, bs’ and bs”, present ( Fig. 7C ). Female fixed finger with 13 teeth, male with ten. Female moveable finger with ten teeth, male with nine. Galea of both sexes divided into two major rami, each terminating in three smaller rami ( Fig. 7D ). Female rallum with seven ( Fig. 7G ) to eight ( Fig. 7H ) long, acuminate blades; most distal blade with small, finger-like, protuberances clustered at distal end; when present on subdistal blade, only single protuberance present. Male rallum with seven long, acuminate blades; distal and subdistal blades with two to three, finger-like, protuberances at distal end, spaced apart ( Fig. 7I ). Lamina exterior absent in both sexes.

Coxae and legs: Pedipalpal coxae same colour, or slightly lighter than rest of pedipalps. Coxae I–IV tan. Legs I–IV light brown to tan in colour. All legs diplotarsate with subterminal tarsal setae dentate distally; claws simple; arolium shorter than claws.

Measurements (mm): Body length ♀ 2.94– 3.14 ♂ 2.26–2.44; Carapace ♀ 0.82–0.85 x 0.82–0.89 (0.96–1.00) ♂ 0.62 –0.68 x 0.70–0.73 (0.88–0.93); Chelicera ♀ 0.64–0.66 x 0.33–0.35 (1.89–1.94) ♂ 0.50 –0.53 x 0.26–0.28 (1.89–1.92), movable finger length ♀ 0.38– 0.40 ♂ 0.31–0.33; Pedipalps: femur ♀ 1.06–1.11 x 0.28–0.30 (3.70– 3.79) ♂ 0.85 –0.91 x 0.22–0.23 (3.86–3.95), patella ♀ 0.88–0.90 x 0.32–0.35 (2.57–2.75) ♂ 0.74 –0.79 x 0.26–0.27 (2.85–2.92), chela ♀ 1.83–1.90 x 0.58–0.64 (2.96–3.16) ♂ 1.59 –1.74 x 0.41–0.47 (3.70–3.88), hand ♀ 0.94–0.97 x 0.58–0.64 (1.52–1.62) ♂ 0.79 –0.89 x 0.41–0.47 (1.89–1.93), movable finger length ♀ 0.95– 0.99 ♂ 0.81–0.88; Leg I: femur ♀ 0.58–0.61 x 0.11–0.12 (5.08–5.27) ♂ 0.48 –0.52 x 0.10 (4.80–5.20), patella ♀ 0.40–0.42 x 0.12–0.13 (3.23–3.33) ♂ 0.32 –0.36 x 0.11 (2.91–3.27), tibia ♀ 0.45–0.47 x 0.10 (4.50–4.70) ♂ 0.36 –0.40 x 0.08 (4.50–5.00), metatarsus ♀ 0.27–0.28 x 0.09 (3.00–3.11) ♂ 0.23 –0.24 x 0.07 (3.28–3.43), tarsus ♀ 0.30–0.31 x 0.07 (4.29–4.43) ♂ 0.25 –0.26 x 0.06 (4.17–4.33); Leg IV femoropatella ♀ 1.07–1.12 x 0.23–0.24 (4.65–4.67) ♂ 0.88 –0.95 x 0.20 (4.40–4.75), tibia ♀ 0.88–0.89 x 0.16 (5.50–5.56) ♂ 0.69 –0.76 x 0.13 (5.31–5.85), metatarsus ♀ 0.38–0.41 x 0.10 (3.80–4.10) ♂ 0.31 –0.35 x 0.08 (3.88–4.36), tarsus ♀ 0.40–0.43 x 0.09 (4.44–4.78) ♂ 0.36 –0.37 x 0.07 (5.14– 5.29).

Remarks. The first specimen of this species was collected from the forests near Knysna in 1947 by R.F. Lawrence, but was misidentified as Gymnobisum quadrispinosum by Beier (1947). Gymnobisium capense sp. nov. is the only gymnobisiid other than G. inukshuk with six setae on the cheliceral hand.

Additional material examined. SOUTH AFRICA: Eastern Cape: 1♀, 2♂, 5 Tritonymphs, 10 Deutonymphs, Stormsrivier , Stormsrivier Forest Nature Reserve , 33°59′S, 23°54′E, 185m a.s.l., Indigenous forest , Leaf litter sifting, leg. J.A. Neethling, 5.XII.2012 ( NMBAP 00331 ) ; 1♀, 1♂, 1 Tritonymph, 1 Deutonymph, Stormsrivier , Tsitsikamma Nature Reserve , 34°1′S, 23°53′E, 47m a.s.l., Coastal forest , Leaf litter sifting, leg. J.A. Neethling, 5.XII.2012 ( NMBAP 00330 ) ; 1♀, Same locality, 34°1′S, 23°53′E, 47m a.s.l., Coastal forest , Leaf litter sifting, leg. J.A. Neethling & C. Neethling, 20.XII.2013 ( NMBAP 00329 ) ; Western Cape: 1♂, Knysna, Diepwalle Forest, 33°57′S, 23°10′E, 548m a.s.l., Indigenous forest , Burlese funnels, leg. J.T. Doyen & C.E. Griswold, 13.XI.1985 (NM 19969) ; 1♀, Same location, Diepwalle Forest [33°56′S, 23°7′E], leg. R.F. Lawrence, 1947 ( SAMC B6911 ) (misidentified as Gymnobisium quadrispinosum ) ; 4♀, 7♂, 1 Tritonymph, Same location, Valley of Ferns , 34°54′S, 23°8′E, 680m a.s.l., Indigenous forest , Leaf litter sifting, leg. J.A. Neethling, 31.I.2017 ( NMBAP 00321 ) ; 1♂, Rheenendal, Jubilee Creek Nature Reserve, 33°53′S, 22°58′E, 308m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling & C. Neethling, 20.XII.2011 ( NMBAP 00317 ) ; 3♀, 3♂, Same location, 33°53′S, 22°58′E, 308m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling, 8.XII.2012 ( NMBAP 00316 ) ; 1♀, 2♂, Same location, 33°53′S, 22°58′E, 308m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling & C. Neethling, 18.XII.2013 ( NMBAP 00315 ) ; 3♂, 2 Tritonymphs, 2 Deutonymphs, 1 Protonymph , Same location, 33°53′S, 22°58′E, 308m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling & C. Neethling, 7.XII.2015 ( NMBAP 00318 ) ; 1♀, 1♂, Wildernis, Hoekville, Woodville Forest , 33°56′S, 22°38′E, 254m a.s.l., Indigenous forest , Leaf litter sifting, leg. J.A. Neethling, 8.XII.2012 ( NMBAP 00320 ) ; 4♀, 2 Tritonymphs, 1 Deutonymph, Same location, 33°56′S, 22°38′E, 254m a.s.l., Indigenous forest , Leaf litter sifting, leg. J.A. Neethling, 29.I.2017 ( NMBAP 00319 ) .

Figures

FIGURE 5. Digital microscope photographs of Gymnobisium capense sp. nov., Female (A, B) and Male (C, D). A, C. Dorsal view; B, D. Ventral view. Scale bar: 1.00 mm.

FIGURE 6. Digital microscope photographs of Gymnobisium capense sp. nov. right chela: Female (A, B) and Male (C, D). A, C. Retrolateral view; B, D. Dorsal view. Scale bar: 1.00 mm.

FIGURE 7. Gymnobisium capense sp. nov. A. Female right chela, retrolateral view; B. Female right pedipalp, dorsal view; C. Female left chelicera, dorsal view; D. Galea; E. Female chelal fingers, anterior retrolateral view; F. Male fixed chelal finger, anterior retrolateral view; G. Female rallum; H. Same; I. Male rallum. Scale bars: A, B: 0.50 mm; C, E, F: 0.20 mm; D, G–I: 0.10 mm.