Nigrisagitta distichus Rosso & Campos

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: 429-434

publication ID

publication LSID

persistent identifier

treatment provided by


scientific name

Nigrisagitta distichus Rosso & Campos

sp. n.

Nigrisagitta distichus Rosso & Campos   , sp. n.

( figs. 1 View FIGURE 1 and 2 View FIGURE 2 )

Etimology. The epithet refers to the linear arrangement of punctures on the median margins of the mandibular plates. Latin: distichus   , with two lines.

Type locality. VENEZUELA, Sucre, Güiria [10.5781, -67.2997] GoogleMaps   .

Holotype. Male. VENEZUELA, Sucre, Güiria (Zát. Poria), Erben. Deposited at the National Museum Praha, Czech Republic ( NMPC).  

Paratypes. 3 females. VENEZUELA, Aragua, El Limon (450 m)   , 1 female, C.J. Rosales, 9.V.1962, [10.3059, -67.6321], ( MIZA); Guarico, Calabozo (7 km ESE Calabozo, Est. Biol. Llanos , 380’, at night) GoogleMaps   , 1 female, 21.VII.1988, [8.86; -67.384444], ( JEE); Las Mercedes del Llano ( Est. Exp. Nicolasito , UCV–FAGRO, Black Light Trap - BLT)   , 1 female, P.H. Freytag, Q. Arias & M.A. Griani, 15. VI   .2000, [9.1102, -66.3972], ( JEE) GoogleMaps   .

Description. Dorsal surface dark yellowish with dense brown punctures irregularly distributed or forming linear arrangements, mainly on head and pronotum; ventral surface yellowish with brown punctures less dense and irregularly distributed along lateral margins.

Head. Punctures between ocelli forming two linear short arrangements divergent anteriorly. Clypeus with punctures along the lateral margins. Proportion of antennal segments: I<II<III<IV<V. Maxillary plates with no punctures. Ocular peduncles weakly punctured and with a brown band lining the limit between each peduncle and respective maxillary plate. Labium pale-yellow; distal half of segment IV darker; labial groove reddish; proportion of labium segments: I<II>III>IV.

Thorax. Hemelytra with spot at apex of radial vein inconspicuous; radial vein continued by a reddish line to the end of corium; membranes surpassing the abdominal apex, translucent, light-brown, and bearing six veins. Femora with scarce brown punctures on distal half of dorsal surface, larger than on body, and with irregular reddish spots; apical 1/3 of tarsal claws black.

Abdomen. Lateral margins of each segment with 1+1 brown spots on anterior and posterior angles and separated by unpunctured area. Median ventral region occasionally stained in red.

Male. Measurements (mm, n=1): total length 7.04; maximum width (on third abdominal segment) 3.91; head length 1.50; width 3.24; clypeus length 0.48; interocellar distance 0.84; interocular distance 2.40; length of antennal segments: I 0.40; II 0.53; III 0.88; IV 1.03; V 1.1; length of labium segments: I 0.65; II 1.35; III 0.58; IV 0.35; pronotum length 1.54; width on humeral angles 3.58; width on anterolateral angles 2.92; scutellum length 3.63; width at base 2.26; frenal lobe length 1.76; post-frenal lobe length 1.87; width on frenal constriction 1.43.

Antennae: segment I yellowish with brown spots, segments II–V brown with yellowish intersegmental areas. Apical margins of hemelytral membranes sub rectilinear. Median portion of posterior margin of urosternites V and VI convex, and of urosternite VII sub rectilinear ( figs. 1B View FIGURE 1 and 3A View FIGURE 3 ).

Genitalia. Pygophore: ventral surface longer than dorsal at midline, with short inconspicuous setae; distal portion of ventral surface dorsally folded and covered by long setae, denser medially; ventral rim “U” shaped ( figs. 3B and D View FIGURE 3 , vr); dorsal rim sinuous, with a flat dark-brown median projection covering the base of segment X ( fig. 3C View FIGURE 3 , dr, drp). Cup-like sclerites not visible from outside the pygophore. Posterolateral angles flattened and welldeveloped, margins sub parallel; dorsal surface concave, medial margins outlined in dark-brown; ventral surface convex, with brown punctures and long setae along the medial margins to the median portion of the apical margins ( figs. 3 View FIGURE 3 B–D, pla). Segment X as long as wide, base narrowed to about 1/2 of the maximum width, posterior margin narrowly arched; dorsal surface convex, medial region black and iridescent, basal region and lateral bands brown; 1+1 lateral tuft of setae on constricted portion; sparse setae on the apical margin ( figs. 3 View FIGURE 3 B–C, X). Exposed portion of parameres subtriangular, brown and ventrally convex; lateral margin convex, medial margin concave, both outlined in dark-brown; apices aculeiform and convergent ( fig. 3B and D View FIGURE 3 , pa). Internal genitalia not examined.

Female. Measurements (mm, n=3): total length 7.77 ± 0.39 (7.43–8.20); maximum width (on third abdominal segment) 4.00 ± 0.06 (3.96–4.07); head length 1.55 ± 0.01 (1.54–1.56); width 3.36 ± 0.08 (3.30–3.42); clypeus length 0.60 ± 0.08 (0.54–0.66); interocellar distance 0.93 ± 0.04 (0.90–0.96); interocular distance 2.49 ± 0.04 (2.46–2.52); length of antennal segments: I 0.45 ± 0.00 (0.45–0.45); II 0.55 ± 0.04 (0.53–0.58); III 0.86 ± 0.02 (0.85–0.88); IV 0.98±0.04 (0.95–1.00) (n=2); V 1.01±0.02 (1.00–1.03) (n=2); length of labium segments: I 0.64 ± 0.02 (0.63–0.65); II 1.34 ± 0.05 (1.30–1.38); III 0.60 ± 0.00 (0.60–0.60); IV 0.36 ± 0.02 (0.35–0.38); pronotum length 1.67 ± 0.08 (1.60–1.76); width on humeral angles 3.78 ± 0.16 (3.69–3.96); width on anterolateral angles 3.03 ± 0.19 (2.92–3.25); scutellum length 3.92 ± 0.27 (3.74–4.24); frenal lobe length 1.87 ± 0.17 (1.71–2.04); postfrenal lobe length 2.05 ± 0.14 (1.93–2.20); width at base 2.48 ± 0.15 (2.37–2.64); width on frenal constriction 1.54 ± 0.11 (1.43–1.65).

Antennae: segments I and II yellowish with brown spots, segments III–V brown with yellowish intersegmental areas. Apical margins of hemelytral membranes convex. Median portion of urosternite VII sub-rectilinear; median portion of tergite VIII convex ( figs. 2B View FIGURE 2 and 4A View FIGURE 4 ).

Genitalia. Laterotergites VIII pale-yellow, weakly punctured; posterior margin slightly convex; band of setae along the posterior margin and sparse setae next to the inner margin; medial portion of laterobasal surface ventrally curved following the median-basal surface of the laterotergites IX ( fig. 5A View FIGURE 5 , la8). Gonocoxites VIII as long as wide, pale-yellow, weakly punctured; long setae along the sutural and posterior margins, setae short and sparse all over the surface; median margin sub-rectilinear; posterior margin medially projected over the laterotergites IX, sinuous and oblique ( figs. 4A View FIGURE 4 , gc8; 4B–C), almost totally covered by a ventrolateral projection ( figs. 4 View FIGURE 4 B–C, vlp). Laterotergites IX surpassing the posterior margin of tergite VIII ( fig. 4A View FIGURE 4 , la9); median and lateral margins sinuous; covered portion flattened, perpendicular to the ventral plane; exposed portion subtriangular, slightly swollen, subparallel to the ventral plane, pale-yellow, not punctured and covered by long setae; apices sharply rounded ( fig. 5A View FIGURE 5 , la9). Gonocoxites IX without median suture; lateral and posterior margins sinuous, the later bearing setae ( fig. 5A View FIGURE 5 , gc9). Segment X exposed between the laterotergites IX and covered by setae ( figs. 4A View FIGURE 4 ; 5A, X View FIGURE 5 ). Ring sclerites absent. Thickening of the vaginal intima ( fig. 5A View FIGURE 5 , vi) laterally flattened, formed by two strongly sclerotized plates subparallel to each other, wider and convergent anteriorly, fused on the posteroventral half, in which the initial portion of the proximal ductus receptaculi is found, the latter opened on the anteroventral half of the vaginal intima. Proximal and distal portions of the ductus receptaculi of same width, the first twice as long as the second. Vesicular area with the proximal 1/5 of outer duct more sclerotized and forming a narrow funnel ( figs. 5A and C View FIGURE 5 , odp); the distal 4/5 of the outer duct expanded and weakly sclerotized ( fig. 5A View FIGURE 5 , od); median duct on the portion next to funnel with smaller caliber, progressively narrowing towards the proximal end ( fig. 5C View FIGURE 5 , mdp); median duct next to the expanded portion of the outer duct with proximal enlargement ( fig. 5A View FIGURE 5 , md); inner duct of same caliber throughout its length ( fig. 5A View FIGURE 5 , id). Pars intermedialis shorter and narrower than capsula seminalis, and widened on distal portion ( fig. 5 View FIGURE 5 A–B, pi). Distal annular crest twice the diameter of the proximal and facing towards the pars intermedialis, the proximal facing towards the ductus receptaculi ( fig. 5B View FIGURE 5 , dac, pac). Capsula seminalis longer than wide, oval, distally sharp, presenting three filiform projections of equivalent length and facing towards the pars intermedialis, one laterobasal, one laterodistal, and one apical ( fig. 5B View FIGURE 5 , cs).

Distribution. Venezuela (Sucre, Aragua, Guarico).

Comments. The inclusion of Nigrisagitta distichus Rosso & Campos   , sp. n. in Discocephalinae   , is based on the insertion of the labium posterior to a transverse imaginary line tangent to the anterior margin of the eyes, and on the tricobothria, lateral to an imaginary line connecting the spiracles ( Rolston & McDonald 1979, Rolston 1981). The classification of N. distichus   in Discocephalini   is proposed based on, the discoid shape of the head, the general shape and color, the dorsal-ventral compression of the body, and the morphology of the genital plates whose gonocoxites VIII project over the gonocoxites IX. As mentioned above, N. distichus   keys to Discocephala   in the identification key of Rolston (1990). However, Nigrisagitta presents the lateral margins of the mandibular plates not sinuous, and lack anteocular processes, while in Discocephala   such margins are sinuous, and reduced convex anteocular processes are observed; in Nigrisagitta the bucculae are slightly higher than the first segment of the labium, while in Discocephala   the bucculae are not well developed ( Becker & Grazia 1992). Also, in Nigrisagitta the scutellum is proportionately narrow on the frenal constriction compared to Discocephala   whose width on the frenal constriction equals 0.75 the basal width of scutellum ( fig. 6A View FIGURE 6 , bw, few). Regarding the male genital morphology, the trapezoid pygophore in Nigrisagitta with long posterolateral angles parallel to the frontal plane, is distinct from the quadrangular pygophore with short posterolateral angles perpendicular to the frontal plane in Discocephala   ( fig. 7 View FIGURE 7 A–C). The shape of the segment X in Nigrisagitta is also distinct from the cordiform one in Discocephala ( Becker & Grazia 1992)   . The female genitalia of Nigrisagitta can be distinguished from Discocephala   ( figs. 8 View FIGURE 8 A–C) by the gonocoxites IX without the median suture line, the lack of ring sclerites, the proximal narrowing of the outer tube of the vesicular area, and the pars intermedialis without a median expansion as seen in Discocephala   ( fig. 8 View FIGURE 8 B–C, drd, rs).


National Museum Prague


Museo del Instituto de Zoologia Agricola Francisco Fernandez Yepez


Belfast Natural History and Philosophical Society


Mykotektet, National Veterinary Institute