Thysanina gracilis, Lyle & Haddad, 2006

Lyle, Robin & Haddad, Charles R., 2006, A revision of the Afrotropical tracheline sac spider genus Thysanina Simon, 1910 (Araneae: Corinnidae), African Invertebrates 47, pp. 95-116 : 107-109

Thysanina gracilis sp. n.

Figs 26–30

Etymology:This species name is Latin for ‘slender’, which refers to the fine, thin slender embolus of the male.

Diagnosis: This species is recognised by the elongated embolus running along the prolateral side of the bulbus. A prominent retrolateral apophysis is found on the tibia, with two smaller apophyses.

Description:

Male.

Measurements: CL 1.1–1.43, CW 0.98–1.28, AL 1.15–1.7, AW 0.8–1.15, TL 2.45–3.0, FL 0.13–0.15, SL 0.69–0.9, SW 0.6-0.78, AME–AME 0.08, AME–ALE 0.03, ALE– ALE 0.32, PME–PME 0.13, PME–PLE 0.11, PLE–PLE 0.52. Length of leg segments (sequence from femur to tarsus, and total): I 1.3+0.63+1.1+0.93+0.6=4.56; II 1.18+0.48+1.05+0.83+0.55=4.09; III 0.88+0.48+0.65+0.8+0.38=3.19; IV 1.4+0.58+ 1.05+1.2+0.48=4.71.

Carapace evenly high for anterior two-thirds, declining posterior to fovea; surface smooth; fovea small and distinct, situated at two-thirds carapace length; carapace dark orange, paler posteriorly. Ocular region orange to dark brown; AER slightly procurved, lateral eyes slightly larger than medians; clypeus height equal to AME diameter; AME separated by distance equal to their diameter; AME separated from ALE by 0.5 AME diameter; PER slightly recurved, median eyes larger than laterals; PME separated by distance equal to 1.5 times their diameter, PME separated from PLE by 0.5 PME diameter. Chelicerae dark orange, with pale setae scattered on anterior surface; three promarginal teeth, proximal and median teeth largest and subequal in size, distal tooth smallest; two retromarginal teeth on same base, distal tooth largest. Sternum bright orange and smooth, darker near border; short, pale orange setae covering surface, long pale setae near border. Abdomen broader anteriorly, truncated posteriorly; dorsum pale yellow to creamy white; dark grey chevron with well pronounced transverse branches. Legs I to IV compact and thickened; pale orange to creamy yellow, with dark brown complete bands on femora to metatarsi; short dark setae ventrally situated on tibiae, metatarsi and tarsi; uniform grey band arrangement on femora, with two close distal bands, patellae covered almost entirely by single band, tibiae and metatarsi with single distal and proximal bands. Leg spination: tibiae: I plv 4 cusps, II plv 3 cusps; metatarsi: I plv 9 cusps, II plv 7 cusps; tarsi: I plv 1 cusps ( Fig. 26 ); regular leg spines absent; palpal spination: femora pl 2, patellae pl 1 do 1, tibiae pl 4 rl 1. Palp orange-brown throughout; prominent spoonshaped dorsal retrolateral tibial apophysis with two smaller retrolateral apophyses; embolus wire-like, originating proximally, running along prolateral side of bulbus, curving distally ( Figs 27, 28 ).

Female.

Measurements: CL 1.23, CW 1.2, AL 2.55, AW 1.8, TL 3.8, FL 0.11, SL 0.88, SW 0.75, AME–AME 0.14,AME–ALE 0.04, ALE–ALE 0.38, PME–PME 0.15, PME–PLE 0.12, PLE–PLE 0.455. Length of leg segments (sequence from femur to tarsus and total):

I 1.35+0.68+1.08+0.88+0.5=4.49; II 1.1+0.6+0.85+0.78+0.43=3.76; III 0.98+0.5+ 0.58+0.63+0.33=3.02; IV 1.33+0.55+1.05+1.2+0.4=4.53.

General appearance similar to male, female larger; dark grey dorsal chevron with short branches pointing sharply towards spinnerets; branches of chevron close to main vein of chevron. AER straight, median eyes larger than laterals; clypeus height equal to 0.5 AME diameter; AME separated by distance equal to their diameter; AME separated from ALE by distance equal to 0.5 ALE diameter; PER slightly recurved, median eyes larger than laterals; PME separated by distance equal to 1.5 times their diameter; PME separated from PLE by distance equal to PME diameter. Chelicerae dark orange, with black setae scattered on anterior surface; three promarginal teeth, proximal and median teeth largest, subequal in size, distal tooth smallest; two retromarginal teeth on same base, distal tooth largest. Legs I to IV less compact, more slender than those of male; band arrangement similar. Regular leg spines, cusps absent; palpal spination: femora pl 3 do 3, patellae pl 1 do 1, tibiae pl 1, tarsi plv 1. Genital area sclerotised, dark brown; copulatory openings laterally off-centre of epigyne; spermathecae globular, terminal receptacles bilobed ( Figs 29, 30 ).

Holotype: ơ ‘R.S.A., Northern Cape Province / Geelkoppies farm / Schmidtsdrift district / 24.I.2002, C.R. Haddad / (light trap) // Araneae / Corinnidae / Trachelinae / Thysanina / gracilis HOLOTYPE ơ / 2005/ 990 det. C. Haddad //’ (NCA # 2005/990).

Allotype: ^‘S. Africa, C.P., Kimberley, Langeberg 138. / Entomol. Staff 2855S, 2436E / Pitfall traps. Apr.– Aug. 1987 // new nr. NMBA01875 // Corinnidae / Trachelinae / Thysanina gracilis / ALLOTYPE //’ (NMBA # 01875).

Paratype: 1ơ ‘ NAMIBIA / Scorpion Mine Site / 27º49'S, 16º36'E / 23–29.VII.1997, E. Griffin / Preservation pitfall traps //’ ( SMN # 43763 ) .

Distribution: Distributed in Northern Cape Province, South Africa, and in southern Namibia ( Fig. 41 ).

Natural history: This species occurs in arid and semi-arid habitats, and was primarily collected from the soil surface.

Figures

Figs 26–30. Thysanina gracilis sp. n.: (26–28) male: (26) schematic representation of cusp arrangement on legs I and II, (27) left palp, ventral view, (28) left palp, retrolateral view; (29, 30) female: (29) epigyne, ventral view, (30) vulva, dorsal view. Scale bar (Figs 27–30) = 0.1mm.

Fig. 41. Distribution of Thysanina in the Afrotropical region.