Thyanta (Argosoma) xerotica 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 : 64-67

Thyanta (Argosoma) xerotica Rider , new species

Figs. 322-336, Map 2

Description. Medium to large; dorsal surface green to brown; often with reddish markings between humeral angles, on apex of scutellum, and sometimes on vertex of head and apices of coria; punctures usually concolorous with surface, sometimes brown.

Outer jugal margins subparallel for middle third of distance from eyes to evenly rounded apex ( Fig. 323). Antennae green to pale brown, distal 3 segments usually marked with dark brown or reddish-brown. Anterolateral margins of pronotum in dorsal view straight to slightly concave; humeral angles rounded to nearly angulate, protruding only slightly beyond base of adjacent coria ( Fig. 322); pronotal cicatrices immaculate. Hemelytra uniformly and densely punctate; posterior margins slightly convex; costal angles narrowly rounded to angulate, reaching beyond middle of penultimate connexival segments; hemelytral membranes hyaline, sometimes with numerous brown flecks. Connexiva narrowly exposed; incisures usually marked with black.

Ventral surface green to pale brown; punctures usually concolorous with surface; humeral angles often marked with black. Rostrum green to brown, apical half of segment 4 piceous, apex reaching beyond middle of third (second visible) abdominal segment. Ostiolar canals acuminate apically. Femora and tibiae green to brown, tarsal segments and apex of each tibia often darker. Postspiracular black spots absent, sometimes vague in brown form; posterolateral angles of abdominal sternites piceous. Mesial margins of basal plates in caudoventral view straight to slightly convex, separated basally; posterior margins sinuous, nearly straight; posteromesial angles broadly rounded ( Fig. 334). Sclerotized rod relatively short, somewhat swollen subapically, distinctly narrowed apically ( Fig. 335); spermathecal duct only slightly swollen and coiled below proximal flange ( Fig. 336). Medial portion of posterior pygophoral margin in caudal view usually concave, continuing line of lateral margins, giving posterior margin a smoothly arcuate form, medial portion sometimes straight and posterior margin more U-shaped ( Fig. 330); pygophore emarginate in lateral view ( Fig. 333); posterolateral angles moderately prominent in both ventral and dorsal views ( Figs. 331, 332). Each paramere relatively robust, concave surface oriented dorsomediad, apex rounded in medial view ( Fig. 324), angulate in ectal view ( Fig. 326), roughened, spiculate area on lateral surface localized, ovoid ( Fig. 325). Each lateral conjunctival lobe of aedeagus with 2 diverticula ( Fig. 329); dorsomedial conjunctival lobe prominent ( Fig. 328); penisfilum relatively small ( Fig. 328).

Measurements. Totallength 6.62-10.25 (7.41); total width 4.34-6.47 (4. 73); medial length ofpronotum 1.40-1.88 (1.49). Medial length ofscutellum 2.72-4.25 (3.13); basal width 2.61-4.08 (2.94); width at distal end offrena 0.94-1.32 (1.05). Length ofhead 1.55-2.07 (1.68); width 1.99-2.65 (2.13). Length of segments 1-5 ofantennae 0.40-0.52 (0.44), 0. 71 -1.10 (0.88), 1.07-1.42 (1.14), 1.18-1.49 (1.47), and 1.14-1.38 (1.31), respectively. Length of segments 2-4 of rostrum 1.25-1.69 (1.42), 0.70-0.92 (0.77), and 0.77-0.99 (0.77), respectively.

Holotype. 5 labeled " Guayaquil Ecua 1940 CLFagen." Deposited in the U. S. National Museum ofNatural History (Washington, D.C.) .

Paratypes. 2855 and 2522. " Ecuador MANABI SAN CLEMENTE VII 84 Legit: F. CUESTA" (5 222 QCAZ) ; " ECUADOR, 82 Km. W. Guayaquil Ricklefs & Austin 8 March 77 " (255 DBT) ; (a) " Guayaquil Ecuador RL Castillo " (b) " Thyanta nitidula Ruckes det H. Ruckes" (2 CU) ; (a) " ECUADOR La Toma 1200m. W.Loja 18,19- XI- 1970 Coll:L.E.Pena" (b) "33" (5 DAR) ; (a) " Peru S.A. I.23 1936 E.G.Smyth " (b) J.R.de la Torre-Bueno Collection K.U." (455 n 2 SMEK) , except 3M labeled " I.25 1936 , " 15 labeled " III.14 1937 , " 12 labeled " III.15 1937 , " and 222 labeled "111.16 1937'' ; (a) " Lima, Peru Feb. 2, 1939 Carl J. Drake" (b) "CJ Drake Coll. 1956" (5 USNM) ; " Peru. Dpto. Amazonas 43 K. ne. Chikiaco 1050' 6-10 XI 1978 L. J. Barkley " (5 LHR) ; (a) " PERU:Dept. Cajamarca Prov. Jaen. Pucara. Rio Huancabamba , 900m 14- 18.1.1964 " (b) " P. C. Hutchison and J. K. Wright Collectors " (5 422 CAS) , except 15 labeled "10- 13.1.1964 " ; " PERU: Dpto. Lambayeque Cerro la Vieja , 7 km. S ofMotupe, el. 100m. 2- l 7-VII- 1981 L. J.Barkley, collector" (5 LHR) ; (a) " 10 Km.S.ofChiclayo, PERU III-21-51 " (b) "Ross and Michelbacher Collectors" (2 CAS) ; " PERU: Dpto. Lambayeque 12 km. N of Olmos el. 90m. l-VII-81 L.J. Barkley, coll." (255 LHR) ; (a) " PERU:Dept. & Prov. Lambayeque. 18 km. W. of Olmos . Alt. 520m 30-IX- 1964 " (b) " P. C. Hutchison & J. K. Wright At Coleman lantern" (5 2 CAS) ; (a) " PERU: 94 mi. E. of Olmos , Lambayeque 1-18-1955 " (b) " E.I.Schlinger & E.S.Ross collectors" (5 CAS) ; (a) " PERU: Lambayeque. Roadside veg. 1 mile S.E. of town. 20.viii.1971." (b) "Fertile irrigated region in arid coastal desert" (c) " P.S.&H.L. Broomfield B.M. 1971 -486 (255 BMNH) ; (a) " Chaclacayo Lima, Peru 750Meters" (b) "Acc.38901 E.Escomel " (2 AMNH) ; (a) " LIMA PERU 1959 F.Cisneros Col." (b) "UA 696-67" (5 DAR) ; (a) " Lima Peru VI- 1 -39 Weyrauch 91" (b) " Thyanta patruelis Stal det H. Ruckes" (2 USNM) ; " PERU: Dpto. Piura Parinas , 7 km. N, 15 km. E Talara 18 -IX-1981 L.J. Barkley, coll." (5 LHR) ; (a) " PERU: Dept. Piura, Prov. Ayabaca. 18 km above Puente Tandopa ( RioQuir6z )" (b) "Alt. 1000-1700 m. 23-IX-1964 P. C. Hutchison & J. K. Wright " (2 CAS) ; " Tamarugal Refresco Enero 16, 1986 D. Bobadilla " (455 UTAC) ; " Tamarugal Enero 30, 86 D. Bobadilla " (5 UTAC) ; " Tamarugal Enero 30, 86 A. Gallardo " (2 UTAC) ; (a) "4" (b) " PAMPA-TAMARUGAL- 16-07 -86 D. BOBADILLA colector" (5 IIAS) ; " CHILE-Arica 19.09.82 Trampa tablero Col. C. Valdes" (2 IIAS); (a) "5 " (b) " TARAPACA CICA.AZAPA LUZ-NEGRA 26-27-1- 70 " (222 IIAS) , except 12 labeled (a) "6" ; (a) " Chile, 194 縠 M. L. Parker " (b) "CJ Drake Coll. 1956" (255 2 USNM) ; and " CHILE. Pica 23.02.84 Vegetaci6n Col. E. Prado" (2 IIAS) .

Distribution. Coastal desert areas from Ecuador to northern Chile ( Map 2).

Comments. This species can be distinguished from other congeners by the form of the posterior margin of the pygophore and by the structure of the parameres. The posterior margin of the pygophore in caudal view is usually arcuately U-shaped. Th_vanta xerotica is the only species of Thyanta with the apex of each paramere distinctly rounded in medial view and usually lacking the obtuse protuberance on the shaft.

Etymology. Named for the xerophytic habitat in which this species lives.