Plinachtus contortus, Brailovsky, Harry & Barrera, Ernesto, 2006

Brailovsky, Harry & Barrera, Ernesto, 2006, Two new species of Plinachtus Stål (Hemiptera: Heteroptera: Coreidae: Coreinae: Gonocerini) from Aldabra Atoll and Madagascar, Zootaxa 1351, pp. 35-43 : 37-39

Plinachtus contortus n. sp.

(Figs. 1, 6)

Description. Holotype male. Head length 1.70; width across eyes 1.75; interocular space 0.97; preocular distance 1.10; interocellar distance 0.44; antennal segments length: I, 2.50; II, 3.15; III, 2.00; IV, 2.10. Pronotal length 2.60; maximal width of posterior lobe including humeral spine 4.10. Scutellar length 1.20; width 1.40. Body length 12.40. Head. Wider than long; antennal segment I cylindrical, thickest, slightly curved outward; segments II and III cylindrical, slender, and IV fusiform; rostrum reaching posterior margin of metasternum. Thorax. Pronotum. Wider than long, declivent; humeral angles thick at base, slightly exposed, and apically truncated; posterior lobe of pronotal disk strongly punctate, anterior lobe including calli scarcely punctate (Fig. 1). Scutellum. Wider than long; apically rounded. Genital capsule. Posteroventral border laterally differentiated into prominent asymmetrical arms; inner arms covered by large, stout, castaneous orange seta-like hairs; middle third with stout short lobe (Fig. 6). Dorsal color. Shiny orange with following areas black: head with two longitudinal stripes running between eye and ocellus, ocellar tubercle, space between antenniferous tubercle and eye, inner face of postocular tubercle, anterolateral margins of pronotum, humeral projections, middle third of anterior lobe of pronotal disk, lateral area of upper third of posterior lobe of pronotal disk, and apex of scutellum; antennal segments I to III shiny orange; IV dull orange suffused with brown, basal and apical thirds pale orange yellow; humeral expansion reddish orange; anterior half of costal margin of corium pale yellowish; basal quarter to half of costal margin border medially by a brownish black stripe; hemelytral membrane pale translucid yellow, basal angle darker; connexival segments pale yellow; dorsal abdominal segments shiny orange yellow. Ventral color. Pale yellow with large black discoidal spot on metapleura; rostral segment I pale yellow, II and III shiny orange, IV shiny orange with apex black; coxa, trochanter, femur pale yellow; tibia pale yellow with distal half shiny orange; tarsus shiny orange.

Female. Head length 1.72; width across eyes 1.72; interocular space 0.97; preocular distance 1.08; interocellar distance 0.42; antennal segments length: I, 2.25; II, 2.70; III, 1.87; IV, 1.72. Pronotal length 2.60; maximal width of posterior lobe including humeral spine 4.05. Scutellar length 1.30; width 1.60. Body length 11.85. Head as longer as wide; apex of antennal segment III barely expanded. Color. Similar to male holotype.

Connexival segments VIII and IX pale yellow, posterior margins shiny orange; abdominal segments VII to IX shiny orange yellow, lateral margins black; genital plates yellow.

FIGURES. 1–6. Plinachtus spp. 1–3. Pronotum. 1, P. contortus n. sp. 2, P. schoutedeni Van Reenen. 3, P. aldabrensis n. sp. 4–6. Male’s genital capsule. Caudal view. 4, P. aldabrensis n. sp. 5, P. schoutedeni Van Reenen. 6. P. c o n t o r t u s n. sp.

Variation. 1. Head dorsally shiny orange, black longitudinal stripes hard to see. 2. Rostral segment II pale yellow. 3. Upper third of pronotal disk laterally shiny orange. 4. Basal quarter to half of costal margin border medially by a shiny orange stripe or incomplete brownish black stripe. 5. Costal margin entirely pale yellow. 6. Tibia yellow with distal joint shiny orange.

Types. Holotype male, Madagascar: Ambanja (without data) (MNHP). Paratypes.

Madagascar: 4 males, 7 females, Sicard 1930 (without data) (MNHN, UNAM); 1 male, Region du Sud, Vallee du Mandrare, Ampasimpolaka, XI-1901, Ch. Alluaud (MNHN); 1 female, Region du Sud, Andrahomana, XI-1901, Ch. Alluaud (MNHN); 1 female, Tulear Pr., St. Augustin S. L., 29-III-1968, K. M. G. y P. D. (BMNH).

Comments. This new species belongs to the dubius- group (van Reenen 1981) characterized by having the posterior third of antennal segments II and III shiny orange or reddish orange (never black), the abdominal sterna without black spots surrounding the abdominal spiracles, the humeral angles thick at base, and the male genital capsule usually with prominent lateral arms. This group includes: P. burgeoni van Reenen, P. dubius Herrich-Schaeffer , P. kivuensis (Schouteden) , P. l u x van Reenen, P. nyamuragirensis (Schouteden) , P. pax van Reenen, P. re x van Reenen, and P. schoutedeni van Reenen.

Plinachtus contortus n. sp., like P. schoutedeni recorded from South Africa, has the humeral angles almost blunt, never ending as sharp spines (Figs. 1–2), ventrally pale yellow with only one large black discoidal spot on the metapleuron, and head dorsally with two black longitudinal stripes running between eye and ocellus.

In P. schoutedeni the anterolateral margins of the pronotum are pale yellow to pale yellowish orange, and the posteroventral margin of the male’s genital capsule has a median lobe more or less rectangular, its lateral angles short, and the external shoulders conical without seta-like hairs (Fig. 5). In P. contortus recorded from Madagascar, the anterolateral margins of pronotum are black to dark brown, and the posteroventral margin of male genital capsule is laterally differentiated into prominent asymmetrical arms, the inner arms are covered with large, stout, castaneus orange seta-like hairs, and the middle third has stout, short lobe (Fig. 6).

Plinachtus dubius is recognized by having the anterolateral margins of the pronotum pale yellow to pale orange, the ventral surface pale yellow with one black discoidal spot on the mesopleuron, and metapleuron, and the posteroventral margin of the male genital capsule laterally differentiated into prominent asymmetrical arms, each arm lacking setalike hairs, and the middle third lacking a stout short lobe.

Etymology. The name refers to the peculiar contorted shape of the male genital capsule.