Nigrisagitta Rosso & Campos, 2017

Rosso, Pedro & Campos, Luiz Alexandre, 2017, Nigrisagitta distichus, a new genus and species of Discocephalini from Venezuela (Hemiptera, Pentatomidae, Discocephalinae), Zootaxa 4303 (3), pp. 427-436 : 428-429

Nigrisagitta Rosso & Campos , gen. n.

Etimology. The name refers to the shape and color of the male segment X. Latin: niger, black; and sagitta, arrow.

Type-species. Nigrisagitta distichus Rosso & Campos , sp. n.

Description. Body elliptical, dorsoventrally compressed, almost twice as long as wide; dorsal surface slightly convex; ventral surface flattened. Male about 90% the length of female ( figs. 1 and 2 ).

Head semicircular, about twice as wide as long; dorsal surface with two small areas without punctures between ocelli and eyes, and scarce punctures between ocelli. Mandibular plates widened and flattened, surpassing and overlapping the apex of clypeus; lateral margins convex; anteocular process absent; ventral surface of mandibular plates with minute black punctures and setae in mid-apical band. Clypeus slightly longer than 1/3 length of the head. Eyes subtriangular, with inner angle sharply rounded. Ocelli placed in line with inner angles of the eyes; interocellar distance slightly larger than the distance between ocelli and eyes. Bucculae slightly higher than first segment of labium and posteriorly divergent. Labium reaching the metacoxae; first segment stouter, inserted posteriorly to the median line of bucculae, and the apex surpassing the anterior margin of prosternum. Antennae with five segments; segment I sub-cylindrical, medially swollen and dorsally covered by the mandibular plates; segments II–IV slightly flattened dorsoventrally, segment V sub-cylindrical; short setae on segments II–V.

Thorax. Pronotum trapezoidal, as long as the head; width at anterolateral angles about 0.9 the width of head; humeral angles rounded. Anterior margin sinuous; lateral margins with denticle next to anterolateral angles; posterior margin sinuous, slightly concave before the scutellum and convex before the hemelytra. Dorsal surface convex, with shallow transverse depression posterior to the cicatrices; cicatrices delimited by linear and discontinuous arrangements of punctures, and bearing irregularly distributed inner punctures; area next to humeral angles swollen. Scutellum weakly convex, reaching or slightly surpassing middle of connexivum VI; basal width about 0.6 the length of scutellum, and 1.6 the width at frenal constriction; post-frenal lobe a little longer than the frenal; basal margin and lateral margins of frenal lobe slightly convex; lateral margins of post-frenal lobe subrectilinear, slightly convergent on the distal 1/3; apex subtriangular and rounded. Hemelytra: corium slightly longer than scutellum, reaching the apical angles of connexivum VI; apical (costal) angle sharply rounded; veins of hemelytral membrane not branching. Prosternum flat; mesosternum arched, with swollen lateral areas delimiting a central groove; metasternum grooved, rhomboidal, and with narrow posterior margin. Evaporatorium subtriangular bearing puctures; ostiolar opening elliptical; peritreme spout-shaped, grooved, slightly curved, not reaching the lateral margin of evaporatorium. Femora clavate, laterally flattened, short and sparse setae present on nearly entire surface, except ventrally where they are longer and denser; tibiae with dorsal surface flattened and punctures larger than the ones found on body, ventral surface convex and with many setae; protibiae with one row of larger apical setae on dorsal margin; tarsomeres I about twice as long as tarsomeres II, and slightly smaller than tarsomeres III; tarsomeres I sub-cylindrical, II and III slightly flattened laterally.

Abdomen. Connexivum exposed on the third to the seventh abdominal segments. Abdominal ventral surface slightly convex, laterally punctured; median region flattened and impunctate; ventral band with no punctures along the lateral margins. Spiracles elliptical. Trichobothria inconspicuous, arranged antero-posteriorly, placed laterally to line connecting spiracles.

Male genitalia. Pygophore trapezoidal ( figs. 3 C–D), dorsoventrally flattened ( fig. 3B ). Posterolateral angles flattened, divergent from the base, apex rounded and parallel to the frontal plane ( figs. 3 B–D, pla). Segment X arrow-shaped and occupying most of the genital cup ( fig. 3C, X ). Parameres inserted ventrally to segment X ( fig. 3B and D , pa).

Female genitalia. Laterotergites VIII sub-rectangular, exposed portion subtriangular ( figs. 4A and 5A , la8); spiracles partially covered ( fig. 5A , sp). Gonocoxites VIII totally covering the gonocoxites IX and partially the laterotergites IX and segment X ( figs. 4A , gc8). Laterotergites IX sinuous, exposed portion subtriangular ( fig. 5A , la9). Gonocoxites IX reduced ( fig. 5A , gc9), their limits with the gonapophyses IX barely distinct ( fig. 5A, g 9). Outer duct of the vesicular area of ductus seminis receptaculi narrowed at proximal end forming a funnel ( figs. 5A and C , odp).

Distribution. Venezuela.

Figures

FIGURE 1. Nigrisagitta distichus Rosso & Campos, sp. n. Holotype male. A, dorsal view; B, ventral view. Abbreviations: bw, basal width of scutellum; fcw, scutellum width on frenal constriction.

FIGURE 2. Nigrisagitta distichus Rosso & Campos, sp. n. Paratype female. A, dorsal view; B, ventral view.

FIGURE 3. Nigrisagitta distichus Rosso & Campos, sp. n. Male. A, ventral view of abdomen posterior portion; B–D, posterior, dorsal and ventral views of pygophore, respectively. Abbreviations: dr, dorsal rim; drp, dorsal rim projection; pa, paramere; pla, posterolateral angle; vr, ventral rim; X, segment X.

FIGURE 4. Nigrisagitta distichus Rosso & Campos, sp. n. Female. A, posteroventral view of urosternite VII and genital plates; B̅C, gonocoxite VIII: ventral and posterodorsal views, respectively. Abbreviations: gc8, gonocoxites VIII; im, inner margin; la8, laterotergites VIII; la9, laterotergites IX; pm, posterior margin; t8, tergite VIII; vlp, ventrolateral projection; X, segment X.

FIGURE 5. Nigrisagitta distichus Rosso & Campos, sp. n. Female. A, receptaculum seminis, ectodermal genital ducts and genital plates; B–C, details of receptaculum seminis. Abbreviations: cs, capsula seminalis; dac, distal annular crest; drd, ductus receptaculi, distal portion; drp, ductus receptaculi, proximal portion; g9, gonapophyses IX; gc9, gonocoxites IX; id, inner duct of vesicular area; idp, inner duct of vesicular area, portion proximal; la8, laterotergites VIII; la9, laterotergites IX; md, median duct of vesicular area; mdp, median duct of vesicular area, proximal portion; od, outer duct of vesicular area; odp, outer duct of vesicular area, proximal portion; pac, proximal annular crest; pi, pars intermedialis; pr, projection; sp, spiracles; t8, tergite VIII; vi, thickening of vaginal intima; X, segment X.