Acrorrhinium tritonion, Yasunaga, Tomohide, Yamada, Kazutaka & Artchawakom, Taksin, 2013

Yasunaga, Tomohide, Yamada, Kazutaka & Artchawakom, Taksin, 2013, New or little known taxa of the plant bug tribe Hallodapini (Hemiptera: Heteroptera: Miridae: Phylinae) from Thailand, with descriptions of three new species of the genus Acrorrhinium Noualhier, Zootaxa 3647 (3), pp. 429-442 : 433-435

Acrorrhinium tritonion new species

(Figs. 1E–F, 2A–B, 4–6)

Diagnosis. Distinguished from other congeners by the velvety brown basic coloration, grayish white inner half of the antennal segment I, crescent white macula on the clavus, and wedge-like white apical margin of the corium (Figs. 1E–F). The fourth instar ( Fig. 2 B) is recognized by the similar color pattern and body shape to the adult, velvety brown general coloration, and noticeable lime-white antennal segment I, median parts of the wing pads and all coxae.

Description. Body generally velvety dark brown, elongate, somewhat elongate-oval posteriorly; dorsal surface matte, partly pruinose or shagreened, nearly glabrous, with very sparsely distributed, pale, short setae. Head subtriangular, with uniformly distributed, silky, erect setae; eye rather small; median projection of frons triangularly overhung, not sharply pointed (Fig. 1F). Antenna fuscous brown, except for inner half of segment I grayish white. Labium shiny chocolate brown, slightly exceeding apex of metacoxa. Pronotum and mesoscutum somewhat pruinosed; scutellum weakly arched medially; pleura dark brown, rather shiny; episternum and ostiolar peritreme creamy yellow. Hemelytron with a crescent white macula just posterior to apex of scutellum and wedgelike white posterior margin of corium; clavus behind white macula rusty; corium with a velvety fuscous, median macula; cuneus velvety fuscous, not much declivous; membrane dark smoky brown. Coxae, except for fuscous procoxa, creamy yellow; leg fuscous; tibia somewhat grayish; tarsus brown. Abdomen dark grayish brown. Male genitalia ( Figs. 4–6 ): Genital segment short ( Fig. 4 ). Left paramere sensory lobe with a short, slender, pointed protuberance ( Fig. 5 ). Phallotheca J-shaped, with weakly pointed apex ( Fig. 4 ). Endosoma medially coiled, with weakly sclerotized apical appendages ( Figs. 5 & 6 ). Female genitalia: Not examined.

Measurements. 3/Ƥ: Total body length 3.2–3.6/ 3.6; length from apex of clypeus to cuneal fracture 2.60– 2.98/ 2.88; head width across eyes 0.73–0.78/ 0.68; vertex width 0.28–0.30/ 0.34; lengths of antennal segment I–IV 0.42–0.45, 1.35–1.40, 1.03–1.16, 0.75–0.78/ 0.45, 1.44, 1.02, 0.72; labial length 1.65–1.76/ 1.65; basal pronotal width 0.90–0.93/ 0.90; width across hemelytron 1.05–1.10/ 1.19; and lengths of metafemur, tibia and tarsus 1.50– 1.53, 2.40–2.55, 0.39–0.44/ 1.65, 2.63, 0.44.

Etymology. From Greek, Triton (= a god of the ocean in the Greek mythology) with a diminutive suffix (-ion), referring to the confirmed habitat of this new species on the beach.

Biology. This new species was found to be associated with a sea (or beach, coast) hibiscus , Hibiscus tiliaceus L. ( Malvaceae ), growing along the coast of the Gulf of Siam ( Fig. 2 A). From this broadleaf several adults and a 4th instar immature form were collected at Ban Phe beach, Rayong Province.

Holotype: 3, THAILAND: Rayong Prov.: Ban Phe coast, 12˚35'N, 101˚25'E, on Hibiscus tiliaceus L., 27–29 Dec 2013, T. Yasunaga & B. Shishido (AMNH_PBI 00379619) ( SUT).

Paratypes. THAILAND: Rayong Prov.: 23, same data as for holotype (00379620–00379621). Nakhon Nayok Prov.: 1Ƥ, Sarika (lodge), N14°18'07" E101°18'09", at light, 21–23 Mar 2010, T. Yasunaga & K. Yamada (00379622) (TYCN).

Additional specimen examined. Rayong Prov.: 1 4th instar, Ban Phe coast, Hibiscus tiliaceus L., 28 Dec 2012, B. Shishido (preserved in Shishido personal collection, Hyogo, Japan).

Remarks. Schuh (1984) indicated the presence of an undescribed species in Thailand. This most probably corresponds to A. tritonion , judging from his comment (a female [specimen from Thailand] is basically castaneous in general coloration with a partial, white, transverse fascia mesially on the clavi).

Figures

FIGURE 2. Habitat of Acrorrhinium tritonion (A) and habitus images of Acrorrhinium spp., living immature individuals (B − F). A. Hibiscus tiliaceus, confirmed breeding host of A. tritonion at Rayong coast. B. Fourth instar of A. tritonion (Rayong). C − F. Fifth instar identical to A. lancialium (Nakhon Nayok).

FIGURE 4. Male genital segment (pygophore) and phallotheca of Thai hallodapines named on the figure. Scale bars 0.2 mm.

FIGURE 5. Male genitalia (left paramere and endosoma) of Thai hallodapines named on the figure. Scale bars 0.1 mm.

FIGURE 6. Images of endosoma of Thai hallodapines named on the figure.