Gymnobisium quadrispinosum (Tullgren, 1907)

Neethling, J. A. & Neethling, C., 2023, A systematic revision of the South African Gymnobisiidae (Pseudoscorpiones: Neobisioidea), Zootaxa 5256 (6), pp. 501-543 : 533-537

Gymnobisium quadrispinosum (Tullgren, 1907)

Figs 24–26

Ideobisium quadrispinosum Tullgren, 1907a: 230–231 , figs 8a–e; Ellingsen, 1912: 88, 118–119.

Holotype: Deutonymph, SOUTH AFRICA, KwaZulu-Natal, Pietermaritzburg, Town Bush [29°33′S, 30°33′E], leg. I. Trägårdh, 13.III.1905 ( NHMG 08-1402 ), not examined.

Gymnobisium quadrispinosum (Tullgren) : Beier, 1931: 304; Beier, 1932: 162, fig. 195; Vachon, 1934: 413; Roewer, 1937: 253; Beier, 1947: 290-291, fig. 3 (misidentification; see G. capense sp. nov.); Beier, 1955: 278; Beier, 1958: 162; Beier, 1964: 35; Beier, 1966: 456, 469; Vitali-di Castri, 1970: 125-126; Muchmore, 1982: 206; Harvey, 1992: 1409; DippenaarSchoeman & Harvey, 2000: 92; Beron, 2002: 34; Harvey et al. 2016: 76, 79.

Diagnosis. Moderately sized species (chela length ♀ 1.37–1.46 mm, ♂ 1.27 –1.35 mm), with chelae more bulbous in females than in males (chela ratio ♀ 3.17–3.24 versus ♂ 3.63 –3.65 times longer than broad); fixed finger multi-toothed structure with six strongly sclerotized teeth; cheliceral hand with five setae; galea with six to seven rami; rallum with eight blades, sub-distal blade sometimes with an apical split. Differs from all congeners by having six teeth on the fixed finger multi-toothed structure.

Description

Carapace: Somewhat broader than long, subquadrate, overall smooth and without furrow. Dark brown males, lighter in females. Two pairs of eyes located dorso-laterally at the front ( Fig. 24A, C ). Small seta located on the dorso-anterior margin of each of the posterior eyes. Female carapace with 22, male carapace with 24 setae, arranged 4: 6: 2: 4: 6(8).

Abdomen: Tergites and sternites smooth, undivided and uniseriate. Abdominal tergites uniformly dark brown in males, lighter in females. 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. Sternites light brown to tan in colour in both sexes, only slightly darkening to posterior of abdomen ( Fig. 24B, D ). Sternites I and II fused and hardy distinguishable. Female operculum with eight setae, loosely grouped in the centre along the fuse line of sternites I and II. Males with 24 setae at the operculum cluster, seven located along the posterior margin of sternite II at the genital opening, 17 additional setae located anteriorly next to these, loosely grouped in the centre of sternite II. Male sternite III with eight setae located on the anterior margin of the sternite, at the genital opening. Pleural membrane cream to light yellow in colour, faintly papillate.

Tergal chaetotaxy: 6(6): 9(10): 8(10): 9(10): 9(11): 9(12): 8(12): 8(11): 8(12): 7(8): 8(8): 2(2).

Sternal chaetotaxy: 8(28):?(?): 20(20): 20(21): 16(19): 17(15): 15(15): 15(14): 14(14): 12(12): 8(8): 2(2). Pedipalp: All segments smooth and orange-brown in colour in both sexes, slightly lighter in females. Trochanter cone-shaped and rounded anteriorly, curved slightly posteriorly. Base narrow, widening distally. Setae present on the anterior surface. Femur very slender, 3.56–3.71 (♀) to 4.04–4.05 (♂) times longer than wide, somewhat constricted basally, widening just distal of base. Deep 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 third segment length, 2.55–2.65 (♂) to 2.73–2.78 (♀) 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. Shallow disto-prolateral excavation present. Setae sparse at base, more numerous on wide part of patella ( Fig. 26B ).

Chela: In both sexes smooth and uniformly orange-brown, lighter in females, fingers may be slightly darker. Female hand larger and slightly more bulbous, strongly convex on the prolateral edge, slightly less so on the retrolateral edge ( Fig. 25A, B ). Male hand smaller, less convex prolaterally ( Fig. 25C, D ). Pedicel slightly constricted at base of chela hand in both sexes, retrolateral condyle small but distinct and rounded. Fingers narrow, shorter than hand (without pedicel) in females, longer than hand (without pedicel) in males, and curved slightly prolaterally. Fixed and movable chelal fingers with eight and four trichobothria respectively ( Fig. 26A ).

Terminal multi-toothed structure extends beyond venom tooth of movable finger in both sexes, curving downward. Female structure ( Fig. 26D ) slightly more curved than male ( Fig. 26E ). In both sexes the structure consists of a large terminal tooth preceded by a row of four smaller, highly sclerotized teeth that decrease in size away from terminal tooth. This row is situated slightly prolaterally behind the terminal tooth. Located retrolaterally at the base of the smaller teeth is another larger tooth. Both fingers with rounded, juxtadentate teeth situated on flexible lamellae. Lamella on female fixed finger originating midway between sb and st, on movable finger at mid finger length. Lamella on both male chelal fingers originating just basal of st. Female fixed finger with 51–53 lightly sclerotized, juxtadentate teeth, 10–11 proximal to lamella base, together with six strongly sclerotized teeth on distal structure. Male fixed finger with 43–44 lightly sclerotized, juxtadentate teeth, 14–15 proximal to lamella base, together with six strongly sclerotized teeth on distal structure. Female movable finger with 51–53 lightly sclerotized, juxtadentate teeth, 16–18 proximal to lamella base. Male movable finger with 41–42 lightly sclerotized, juxtadentate teeth, 15–16 proximal to lamella base. Two thickened, spine-like setae present on distal end of movable finger in both sexes.

Chelicera: Hand with five long and acuminate setae, es shorter ( Fig. 26C ). Female fixed finger with nine teeth, male with ten. Female moveable finger with ten teeth, male with seven. Galea of females divided into seven rami ( Fig. 26F ), six in males ( Fig. 26G ). Rallum of both sexes with eight long, acuminate blades. Distal blade with a small, blunt protuberance along the upper blade, subdistal blade with single protuberance at terminal ( Fig. 26H ). Lamina exterior absent in both sexes.

Coxae and legs: Pedipalpal coxae same colour, or slightly lighter than rest of pedipalps. Both leg coxae as well as legs tan in colour. All legs diplotarsate with subterminal tarsal setae dentate distally; claws simple; arolium shorter than claws.

Measurements (mm): Body length ♀ 2.45– 2.61 ♂ 1.99–2.06; Carapace ♀ 0.66–0.68 x 0.68–0.73 (0.93–0.97) ♂ 0.62 –0.65 x 0.70–0.72 (0.88–0.90); Chelicera ♀ 0.53–0.56 x 0.29–0.30 (1.83–1.87) ♂ 0.41 –0.44 x 0.20–0.22 (2.00–2.05), movable finger length ♀ 0.32– 0.34 ♂ 0.25–0.26; Pedipalps: femur ♀ 0.82–0.89 x 0.23–0.24 (3.56– 3.71) ♂ 0.85 –0.89 x 0.21–0.22 (4.04–4.05), patella ♀ 0.78–0.82 x 0.28–0.30 (2.73–2.78) ♂ 0.69 –0.74 x 0.26–0.29 (2.55–2.65), chela ♀ 1.37–1.46 x 0.43–0.45 (3.17–3.24) ♂ 1.27 –1.35 x 0.35–0.37 (3.63–3.65), hand ♀ 0.74–0.78 x 0.43–0.45 (1.72–1.73) ♂ 0.70 –0.71 x 0.35–0.37 (1.92–2.00), movable finger length ♀ 0.61– 0.65 ♂ 0.61–0.62; Leg I: femur ♀ 0.40–0.44 x 0.11–0.12 (3.64–3.67) ♂ 0.38 –0.41 x 0.12 (3.17–3.42), patella ♀ 0.29–0.31 x 0.10–0.11 (2.82–2.90) ♂ 0.32 –0.33 x 0.11 (2.91–3.00), tibia ♀ 0.36–0.38 x 0.10 (3.60–3.80) ♂ 0.36 –0.40 x 0.10 (3.60–4.00), metatarsus ♀ 0.19–0.20 x 0.08 (2.37–2.50) ♂ 0.18 –0.19 x 0.08 (2.25–2.37), tarsus ♀ 0.21–0.22 x 0.07 (3.00–3.14) ♂ 0.20 –0.22 x 0.07 (2.86–3.14); Leg IV femoropatella ♀ 0.79–0.84 x 0.21–0.22 (3.76–3.82) ♂ 0.75 –0.82 x 0.19– 0.22 (3.73–3.95), tibia ♀ 0.70–0.72 x 0.12–0.13 (5.54–5.83) ♂ 0.61 –0.68 x 0.11–0.13 (5.23–5.55), metatarsus ♀ 0.30–0.32 x 0.10 (3.00–3.20) ♂ 0.27 –0.30 x 0.09 (3.00–3.33), tarsus ♀ 0.35–0.38 x 0.09 (3.89–4.22) ♂ 0.33 –0.36 x 0.08 (4.12–4.50).

Remarks. The first gymnobisiid to be described from South Africa more than a century ago, Tullgren’s original 1907 Ideobisium quadrispinosum description was based on a deutonymph from Pietermaritzburg in KwaZulu-Natal. Beier (1931) later used this description to create the genus Gymnobisium , where he nominated I. quadrispinosum as the type and only species. Only in 1947 did Beier recognize that the descriptions for both the species and genus were based on an immature specimen. He proceeded to update both descriptions using an adult specimen collected from the Knysna Forest in the Western Cape, which he identified as belonging to G. quadrispinosum . The adult specimen was, of course, not a G. quadrispinosum , but a specimen of G. capense sp. nov., resulting in the new description to be erroneous. The above redescription thus represents the first true description of G. quadrispinosum , as it was made via examination of both historic as well as recently collected adult specimens from around the species’ type locality. Furthermore, with the exception of the single holotype specimen for G. octoflagellatum , all other historic gymnobisiid specimens were identified as G. quadrispinosum , giving the species a distribution ranging from Charlestown in northern KwaZulu-Natal to Table Mountain in the southern Western Cape. Many of these identifications were found to be erroneous, with these specimens belonging to several of the other South African species of gymnobisiids. G. quadrispinosum ’s distribution range has now been established to be restricted mainly to the KwaZulu-Natal province, with a single record from the Eastern Cape. Harvey et al. (2016) provided sequence data for a specimen from Champagne Castle Hotel that can likely be referred to this species.

Additional material examined. SOUTH AFRICA: KwaZulu-Natal: 1♂, Bergville, Royal Natal National Park, Mount-Aux-Sources [28°44′S, 28°55′E], leg. R.F. Lawrence, III.1946 ( NMSA 683 ); 3♀, 1♂, Bulwer [29°48′S, 29°46′E], leg. R.F. Lawrence, III.1938 ( NMSA 5122 ); 2♀, 1♂, Same location, leg. W.G. Rump, II.1947 ( NMSA 685 ); 1♂, Same location, Marutswa Forest , 29°48′S, 29°47′E, 1464m a.s.l., Afromontane forest , Leaf litter sifting, leg. J.A. Neethling, 6.IV.2017 ( NMBAP 00332 ); 1 Tritonymph, Charlestown, Laings Nek Pass [27°29′S, 29°52′E], leg. C. Akerman, XII.1947 ( NMSA 5121 ); 1 Tritonymph, 1 Deutonymph, Estcourt, Cathkin Peak [29°6′S, 29°24′E], leg. R.F. Lawrence, I.1943 ( NMSA 664 ); 4♀, 3♂, Greytown, Mazongwaan Forest [29°3′S, 31°51′E], leg. R.F. Lawrence, XI.1940 ( NMSA 5117 ); 1 Tritonymph, Howick, Dargle Area [29°28′S, 30°3′E], leg. W.G. Rump, XI.1942 ( NMSA 5120 ); 1♂, Same location, Karkloof [29°18′S, 30°14′E], leg. W.G. Rump & R.F. Lawrence, XII.1941 ( NMSA 663 ); 1♂, Newcastle, Ncandu Forest Nature Reserve , 27°54′S, 29°42′E, 1623m a.s.l., leg. D. Herbert, 31.I.1996 (NM 20303) ; 1♂, New Hanover, York District [29°20′S, 30°29′E], leg. R.F. Lawrence, V.1940 ( NMSA 644 ); 1♀, 3♂, Nottingham Road , Umgenipoort Farm [29°29′S, 30°54′E], leg. R.F. Lawrence, XII.1935 ( NMSA 598 ); 1♀, Pietermaritzburg [29°33′S, 30°33′E], leg. K.N.B., XI.1917 ( NMSA 16052 , previously B1387); 1♀, 5 Tritonymphs , 3 Deutonymphs , Same location, Rietvlei District , Geikies Farm , 30°29′S, 29°50′E, 823m a.s.l., leg. R.F. Lawrence, XI.1960 ( NMSA 7868 ); 1♀, Same location, Town Bush [29°33′S, 30°33′E], leg. R.F. Lawrence, I.1940 ( NMSA 5118 ); 1♂, Van Reenen [28°23′S, 29°23′E], leg. H.C. Bu …(?), III.1918 ( SAMC C2116 ); 1♀, 1 Deutonymph, Winterton, Champagne Castle Hotel [29°3′S, 29°25′E], leg. R.F. Lawrence, II.1941 ( NMSA 5119 ); 1♂, Same location [29°3′S, 29°25′E], leg. R.F. Lawrence, I.1946 ( NMSA 682 ); 1♂, Same location [29°3′S, 29°25′E], leg. R.F. Lawrence & A.G. Lawrence, I.1953 ( NMSA 5100 ); 1♂, Same location [29°3′S, 29°25′E], leg. R.F. Lawrence, I.1957 ( NMSA 5108 ); 1♀, 1 Deutonymph, Same location [29°3′S, 29°25′E], leg. R.F. Lawrence, I.1958 ( NMSA 5161 ); 1♀, Same location [29°3′S, 29°25′E], leg. R.F. Lawrence, I.1959 ( NMSA 5168 ) .

Figures

FIGURE 24. Digital microscope photographs of Gymnobisium quadrispinosum (Tullgren, 1907), Female (A, B) and Male (C, D). A, C. Dorsal view; B, D. Ventral view. Scale bar: 1.00 mm.

FIGURE 25. Digital microscope photographs of Gymnobisium quadrispinosum (Tullgren, 1907) right chela: Female (A, B) and Male (C, D). A, C. Retrolateral view; B, D. Dorsal view. Scale bar: 1.00 mm.

FIGURE 26. Gymnobisium quadrispinosum (Tullgren, 1907). A. Female right chela, retrolateral view; B. Female right pedipalp, dorsal view; C. Female left chelicera, dorsal view; D. Female chelal fingers, anterior retrolateral view; E. Male fixed chelal finger, anterior retrolateral view; F. Female galea; G. Male galea; H. Rallum. Scale bars: A, B: 0.50 mm; C–E: 0.20 mm; F–H: 0.10 mm.