Stilobezzia (Acanthohelea) spinosa Cazorla and Spinelli sp. nov.

(Figures 11, 21)

Diagnosis

The only Patagonian species of Stilobezzia (Acanthohelea) in which males have three distal, elongated spines on hind tibia and first tarsomere of hind leg with a row of spines. Females spermathecae ovoid and hyaline with sclerotized, short necks.

Male. Head (Figure 11A). Dark brown. Antennal flagellum brown; plume dark brown, poorly developed; antennal ratio 1.02–1.09 (1.05, n = 5). Palpus brown; segment 3 slightly longer than 5; palpal ratio 3.71–4.29 (3.20, n = 10).

Thorax. Scutum dark brown, humeral pits yellowish; scutellum yellowish with 11 large setae; postscutellum dark brown. Legs brown, with dense dark setae, hind leg stouter; hind tibia with three distal, elongated spines; tarsomere 1 of hind leg with row of spines (Figure 11C); hind tibial comb with 7–8 spines; prothoracic TR 1.85–2.00 (1.95, n = 10); mesothoracic TR 1.85–2.00 (2.06, n = 9); metathoracic TR 2.16–2.40 (2.25, n = 10). Wing (Figure 11B) length 1.70–1.94 (1.81, n = 10) mm, width 0.57– 0.67 (0.62, n = 10) mm, costal ratio 0.69–0.71 (0.70, n = 10); membrane slightly infuscated; second radial cell 2.62–3.50 (3.30, n = 10) × longer than first; cubital fork originating at level of base of r-m cross vein; macrotrichia on costa, R 1, R 2, R 3, M 1, M 2, sparse on cell r 3. Halter pale.

Abdomen. Brown, with dense setae. Genitalia (Figures 11D, E) dark brown; tergite 9 extending 0.86× of gonocoxites length, posterior margin rounded; sternite 9 hyaline, spiculate, posterior margin convex; sternite 10 spiculate, produced beyond base of cerci; cerci slender, divergent. Gonocoxite very stout, 1.28× longer than greatest breadth, gonostylus slightly shorter than gonocoxite, curved, basal portion stout, narrowing to rounded tip. Parameres subparallel (Figure 11E), apodemes slender; stem short, stout, broadening distally, tip ladle-shaped. A small triangular sclerite located at proximal 1/3 of stem of parameres. Aedeagus 0.8× length of basal breadth, composed of two sclerites with basal 2/3 very slender, curved, distal 1/3 swollen with mesally directed pointed tip.

Female. Similar to male, with the following notable differences:

Head (Figure 11F) dark brown. Antennal flagellum dark brown; antennal ratio 1.19–1.41 (1.33, n = 7). Palpal ratio 3.00–3.33 (3.19, n = 7). Mandible with 7 coarse teeth.

Thorax (Figure 11H). Scutellum with 11 stout, 8 thinner setae; hind tibial comb with 7 spines; claws stout, shorter than tarsomeres 5; hind tibial comb with 9–10 spines; prothoracic 2.00–2.20 (2.10, n = 7); mesothoracic TR 2.00–2.17 (2.10, n = 7); metathoracic TR 2.36–2.50 (2.49, n = 7). Wing (Figure 11G) length 1.88–1.94 (1.91, n = 7) mm, width 0.73–0.76 (0.75, n = 7) mm, costal ratio 0.71–0.75 (0.74, n = 7), second radial cell 3.11–3.85 (3.52, n = 5) × longer than first; cubital fork originating slightly distal to level of base of r-m cross vein; macrotrichia on costa, R 1, R 2, R 3, M 1, M 2, Cua 1, abundant on cells r 3, m 1, sparse on cell cua 1.

Abdomen. Genitalia (Figure 11I): anterior margin of sternite 8 slightly concave; posteromedian excavation V-shaped; sternite 10 with 6–7 pairs of setae; cerci conspicuous, rounded; two ovoid, hyaline spermathecae with sclerotized, short necks, measuring 7.40–8.50 (7.80, n = 7) by 5.50–7.40 (6.50, n = 7) µm and 5.90–8.50 (6.40, n = 7) by 4.40–5.90 (5.30, n = 7) µm; plus a third rudimentary spermatheca.

Distribution

Argentina (Río Negro) (Figure 21).

Types

Holotype male, allotype female, Argentina, Río Negro, Parque Nacional Nahuel Huapi, Puerto Blest, mallin La Heladera, 41°00 ′ 56 ″ S, 71°49 ′ 45.4 ″ W, 878 m, 7 January to 4 February 2007, A. Garré – F. Montes de Oca – J. Massaferro, Malaise trap (MLPA). Other paratypes: 9 males, 6 females, as follows: same data as holotype, 5 males; Argentina, Río Negro prov., Parque Nacional Nahuel Huapi, arroyo Ñireco (Complejo Challhuaco), 41°11 ′ 51.9 ″ S, 71°19 ′ 40 ″ W, 962 m, 20 December 2006 to 23 January 2007, J. Massaferro – A. Garre – F. Montes de Oca, 2 females, 2 males Malaise trap; Parque Nacional Nahuel Huapi, Puerto Blest, mallin La Heladera, 41°00 ′ 56 ″ S, 71°49 ′ 45.4 ″ W, 878 m, 15 December 2006 to 7 January 2007, A. Garré – F. Montes de Oca – J. Massaferro, 2 males, 4 females, Malaise trap.

Etymology

The name spinosa refers to the spinose first tarsomere of hind leg.

Discussion

This species strongly resembles S. (A.) succinea . The latter species can be distinguished by the general coloration yellowish brown, the apex of hind tibia darker, the inner margin of gonocoxite with a pointed tubercle and the sclerotized spermathecae.