Thyanta (Argosoma) sinuata Rider, 1991

Rider, D. A. & Chapin, J. B., 1991, Revision Of The Genus Thyanta Stal, 1862 (Heteroptera: Pentatomidae) I. South America, J. New York Entomol. Soc. 99, No. 1, pp. 1-77 : 60-62

Thyanta (Argosoma) sinuata Rider , new species

Figs. 300-307, Map 2

Description. Small to medium; dorsal surface pale yellowish-green, lacking all red or black markings; punctures slightly darker than surface, sparse everywhere except along anterior margin of pronotum.

Apex of head narrowly rounded; outer jugal margins not quite parallel ( Fig. 301). Antennae pale brown, distal 3 segments darker. Anterolateral margins of pronotum in dorsal view almost straight, nearly devoid of punctures submarginally; humeral angles rounded, protruding only slightly beyond base of adjacent coria ( Fig. 300); pronotal cicatrices immaculate. Hemelytra shallowly and sparsely punctate; posterior margins slightly convex; costal angles narrowly rounded, reaching to near posterior margin of penultimate connexival segments; hemelytral membranes hyaline with a few distal brown flecks. Connexiva usually narrowly exposed, incisures sometimes minutely marked with piceous.

Ventral surface yellowish-brown; posterolateral angles of abdominal sternites immaculate; postspiracular black spots lacking. Rostrum pale yellowish-green, apical half of segment 4 piceous, extending onto base of abdomen; femora and tibiae green to brown, tarsal segments sometimes darker. Ostiolar canals acuminate apically.

Mesia} margins of basal plates in caudoventral view convex; posterior margins sinuous; posteromesial angles shallowly emarginate ( Fig. 305). Distal end of sclerotized rod swollen subapically, narrowed apically ( Fig. 306); spermathecal duct with small amount of swelling and coiling below proximal flange ( Fig. 307). Posterior margin of pygophore in caudal view shallowly and sinuously V-shaped ( Fig. 302); posteroventral surface only feebly produced into blunt, chin-like protuberance in ventral view ( Fig. 303); emarginate in lateral view ( Fig. 304). Concave surface of each paramere oriented dorsomediad; each paramere robust; in medial view apex broad, nearly angulate, not curving dorsad.

Measurements. Total length 6.62-7.89 (6.62); total width 4.49-5.50 (4.49); medial length of pronotum 1.25-1.55 (1.25). Medial length of scutellum 2.86-3.31 (2.86); basal width 2.80-3.09 (2.80); width at distal end of frena 0.96-1.10 (0.96). Length ofhead 1.46-1.59 (1.46); width 1.94-2.12 (1.94). Length of segments 1-5 ofantennae 0.37 (0.37), 0. 74-0.79 (0.74), 0.88-0.92 (0.92), 0.96-0.98 (0.96), and 0.92-0.96 (0.92), respectively. Length of segments 2-4 of rostrum l.18-1.21 (l.18), 0.70-0.72 (0.70), and 0.66-0.68 (0.66), respectively.

Holotype. 5 labeled (a) " COLOMB Magdal. Santa Marta X-8-71 GEBohart" (b) "Thyanta signoreti Ruckes LHR 74." The holotype specimen is in poor condition having the abdomen partially loose from the rest of the body. Deposited in the U.S. National Museum of Natural History (Washington, D.C.) .

Paratypes. 15, 299. Labeled same as holotype except lacking (b) (9 DAR, 9 LHR); and (a) " AcariguaEst . Portuguesa Ven. VI-81 " (b) "CJ Drake Coll. 1956" (5 USNM) .

Distribution. Colombia and Venezuela ( Map 2).

Comments. The form of the posterior pygophoral margin and the structure of the parameres are unique within the genus. The sparse overall punctation will also help identify this species. Due to the poor condition of the holotype, the male genitalia were not dissected, but the characters of the parameres are visible without dissection.

Etymology. Named for the sinuously V-shaped posterior margin of the pygophore.