Touranella gracilis Attems 1937

Touranella gracilis Attems, 1937 Figs 2, 3 Touranella gracilis Attems 1937: 231 (D). Touranella gracilis – Attems 1938: 233 (D); Jeekel 1968: 64 (M); Golovatch 1983: 182 (M); 1994: 186 (D, M); 2009 a: 6 (M, K); 2009 b: 120 (M); 2016: 139 (M, K); Enghoff et al. (2004): 40 (L); Golovatch and Semenyuk 2010: 125 (M); 2018: 16 (M); Nguyen and Sierwald 2013: 1180 (L); Nguyen et al. 2023: 170 (M, K). Type material examined. Holotype. • ♂ (NHMW-3531), Vietnam, Danang Province, Lienchieu, 1931, leg. C. Dawydoff. Paratype. • ♀ (NHMW-3531), same locality, together with holotype. Redescription. Length 12.5 (♂) or 14.4 mm (♀), width of midbody pro- and metazona 0.73 and 0.97 mm (♂) or 1.17 and 1.47 mm (♀), respectively. Coloration of alcohol material after long-term preservation dark red brown (Fig. 2 A – G, J – L) with pale castaneous brown paraterga and epiproct, yellowish antennae, venter, and legs (Fig. 2 A – L) (vs body color almost black with pale yellowish antennae and legs, as given in the descriptions by Attems 1937). Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae rather short, reaching to body ring 3 (♂) or ring 2 (♀) when stretched dorsally. In width, ring 2 <3 <collum <head <ring 4 <5–16 (♂, ♀), thereafter body gently and gradually tapering towards telson. Collum with abundant, small, setiferous knobs; anterior edge broadly rounded, narrowly bordered, fused to callus; caudal corner very broadly rounded, not produced past the rear tergal margin; lateral edge with two-minute incisions, slightly declined ventrad (Fig. 2 A, B, J). Tegument smooth and shining, prozona very finely shagreened, metaterga roughly granulate-tuberculate and shagreened; surface below paraterga finely microgranulate (Fig. 2 A – F, J – L). Postcollum metaterga with abundant, small, irregular, setiferous knobs. Tergal setae long, slender, ~ 1 / 2 length of metaterga. Axial line rather faint but traceable both on pro- and metaterga. Paraterga strongly developed (Fig. 2 A – F, J – L), lying low (at ~ 1 / 2–1 / 3 midbody height); anterior edge narrowly rounded and narrowly bordered, fused to callus; caudal corner narrowly rounded to nearly pointed, not produced past the rear tergal margin; lateral edge with three evident, lateral, setigerous incisions on poreless calluses and two strong ones (anterior) on pore-bearing calluses. Calluses on paraterga delimited by a sulcus only on dorsally. Ozopores evident, lateral, each lying in an ovoid groove at ~ 1 / 4 in front of caudal corner. Transverse metatergal sulci usually distinct (Fig. 2 A, C, F, K, L), incomplete on ring 4, complete on metaterga 5–18, line-shaped, very deep, not reaching bases of paraterga, faintly ribbed at bottom. Stricture between pro- and metazona wide, line-shaped, rather deep, evidently ribbed at bottom down to base of paraterga (Fig. 2 A – F, K, L). Pleurosternal carinae with an anterior narrowly rounded crest on ring 2, thereafter missing. Epiproct (Fig. 2 E, G) conical, flattened dorsoventrally, with two-minute apical papillae; tip subtruncate; pre-apical papillae absent. Hypoproct subtriangular, setiferous knobs at caudal edge well-separated and evident (Fig. 2 G). Sterna sparsely setose, without modifications; an entire, short, linguiform, setose sternal lobe between ♂ coxae 4 (Fig. 2 H, I). A paramedian pair of evident tubercles in front of gonopods aperture. Legs moderately long and slender, slightly incrassate in ♂, midbody legs ~ 1.3–1.4 (♂) or 1.0–1.1 × (♀) as long as body height, prefemora without modifications, ♂ tarsal brushes absent. Gonopods simple and stout (Fig. 3 A, B); coxa slightly curving caudally, densely setose distodorsally. Prefemoral part (pfe) densely setose, ~ 1 / 4 the length of acropodite (femoral part + postfemoral part) (Fig. 3 A, B). Femoral part (fe) strongly reduced, with a prominent, simple, lance-shaped lateral prefemoral process (fp) (Fig. 3 B) and a fully medial, strong, long, flagelliform solenomere (sl) (Fig. 3 A, B). Solenophore (sph) suberect, slightly twisted distally, strongly developed, sheathing most of solenomere (sl), with a lateral shoulder (u) at the base, distally bearing a pointed process (e) and a narrow unciform lamona (g) (Fig. 3 A, B). Distribution. It is known only from the type locality and appears to be endemic to Vietnam. Remarks. Although Golovatch (1994) examined and illustrated the gonopodal structure of this species, nearly all other morphological features remained ignored. The present study provides a comprehensive description of the species which appears to be endemic to Vietnam.