Plinachtus aldabrensis, 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 : 39-42

Plinachtus aldabrensis n. sp.

(Figs. 3–4, 7)

Description. Holotype male. Head length 1.45; width across eyes 1.60; interocular space 0.85; preocular distance 0.90; interocellar distance 0.43; antennal segments length: I, 1.55; II, 2.00; III, 1.45; IV, 1.75. Pronotal length 1.90; maximal width of posterior lobe including humeral spine 3.10. Scutellar length 1.07; width 1.15. Body length 9.65. Head. Wider than long; antennal segment I cylindrical, thickest, slightly curved outward; segment II cylindrical; III cylindrical, apically weakly expanded; and IV fusiform; antennal segment II the longest, III the shortest or subequal to I, and IV longer than I and than III; rostrum reaching middle third of metasternum. Thorax. Pronotum. Wider than long, declivent; humeral angles thick at base; humeral spine tapering into short and robust spine, pointing outward, slightly backward, not upward or forward; pronotal disk strongly punctate, except for calli, these with a few scattered punctures (Fig. 3). Scutellum. Wider than long, scarcely punctate; apically subtruncated. Abdomen. Posterior angle of connexival segment VI with stout spine. Genital capsule. Posteroventral border with lateral arms wide, stout, gently conical, with large u-shaped medial concavity, and outer shoulders relatively small (Fig. 4). Dorsal color. Head, pronotum, scutellum pale yellow with following areas black to dark brown: head lateral to mid line 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, and almost all punctures of posterior lobe of pronotal and scutellar disk; antennal segments I and II orange, III orange with apical third suffused with pale brown; IV orange with middle third suffused with pale brown; clavus and corium dark yellow suffused with reddish orange, punctures dark brown; anterior half of costal margin of corium pale yellow; basal quarter to half of costal margin bordered medially by brownish black stripe; hemelytral membrane translucent, basal angle pale brown; connexival segments pale yellow; dorsal abdominal segments pale yellowish orange, anterior angle of segments III to VII black. Ventral color. Pale yellow with large black discoidal spot on mesopleuron and metapleuron; rostral segment I yellow, II to IV pale orange (apex of IV black); legs pale yellow, apical third of tibiae and tarsi pale orange.

Female. Head length 1.75; width across eyes 1.85; interocular space 0.95; preocular distance 0.97; interocellar distance 0.52; antennal segments length: I, 1.60; II, 2.30; III, 1.62; IV, 1.75. Pronotal length 2.40; maximal width of posterior lobe including humeral spine 3.67. Scutellar length 1.35; width 1.60. Body length 11.50. Color. Similar to male holotype. Rostral segments I to III pale yellow and IV orange with apex black; anterolateral margins of pronotum black, outer margin and humeral spines pale reddish orange; abdominal segments II to IX brownish black, middle irregular longitudinal stripe yellow; connexival segments III to IX, and genital plates pale yellow.

Types. Holotype male, Aldabra South Island: Frigate Pool, 20-I-1968, B. Cogan and A. Hutson (Aldabra Atoll Royal Expedition, 1967-68, BM) (BMNH). Paratypes. Aldabra South Island: 1 male, Frigate Pool, 20-I-1968, B. Cogan and A. Hutson (Aldabra Atoll Royal Expedition, 1967-68, BM) (UNAM); 1 female, Anse Cedre, 17-19-I- 1968, B. Cogan and A. Hutson (Aldabra Atoll Royal Expedition, 1967-68, BM) (BMNH); 1 female, Takamaka, 1-17-II-1968, B. Cogan and A. Hutson (Aldabra Atoll Royal Expedition, 1967–68, BM) (BMNH).

Comments. This species also belongs to the dubius -group (van Reenen 1981) and like P. shoutedeni van Reenen (1981), has humeral angles almost blunt, never ending in sharp spine; and on the posteroventral border of the male genital capsule the median exposed lobe is more or less rectangular (Figs. 4–5).

In P. aldabrensis n. sp., the anterolateral margins of the pronotum are black, the posterior angle of connexival segment VI is projected in a robust spine, the humeral spine is stout and directed backward, the apex of the scutellum is yellow, and abdominal segments III to VI yellow with strong black to brownish black marks. Plinachtus schoutedeni recorded from South Africa has the anterolateral margins of the pronotum pale yellow to orange, the posterior angle of connexival segment VI unarmed, the humeral spine tiny, the apex of the scutellum black, and abdominal segments III to VI shiny yellowish orange without black or brownish black marks.