The genus Xylocoris found from plant debris in Thailand, with description of a new species of the subgenus Arrostelus (Hemiptera: Heteroptera: Anthocoridae) Author Yamada, Kazutaka Tokushima Prefectural Museum, Bunka-no-Mori Park, Mukôterayama, Hachiman-chô, Tokushima, 770 - 8070 Japan; e-mail: yamada. kaz @ gmail. com Author Yasunaga, Tomohide Research Associate, American Museum of Natural History, New York 10024; e-mail: tyasunaga @ amnh. org Author Artchawakom, Taksin Sakaerat Environmental Research Station (SERS), Sakaerat Biosphere Reserve, Thailand Institute of Scientific & Technological Research (TISTR), Ministry of Science and Technology, 1 Moo 9, A. Udom Sab, Wang Nam Khieo, Nakhon Ratchasima, 30370 Thailand; e-mail: sakaerat @ tistr. or. th Author Sers text Acta Entomologica Musei Nationalis Pragae 2013 2013-11-15 53 2 493 504 journal article 10.5281/zenodo.5740713 0374-1036 5740713 5FF3E23F-454D-41BF-9696-818A8F2B4B6E Xylocoris ( Arrostelus ) ampoli Yamada & Yasunaga , sp. nov. ( Figs 1–3 , 5–8, 11–27 ) Type locality. Thailand , Suphan Buri Prov. , Sri Prachan (14°41′18.3″N, E100°08′25.8″ E). Type materials. HOLOTYPE : J (brachypterous, Figs 5, 6 ), ‘ THAILAND : Suphan Buri / Sri Prachan / N14°41′18.3″ / E100°08′25.8″ / 10 m alt., 25.x.2008 / T. Yasunaga & K. Yamada leg.’ ( SUT ) . PARATYPES : THAILAND : same label as holotype , 3 JJ (brachypterous, one in Figs 16 , 19–27 ), 7 ♀♀ (5 brachypterous, one in Fig. 11 and other in Figs 13–15 ; 2 macropterous) (all in TKPM except for 1 J 1 ♀ in TYCN ) . INDONESIA : 4 JJ (NSMT-I-He-66018- 66021, macopterous, one in Figs 7, 8, 12 , 17 ), 1 ♀ (NSMT-I-He-66022, macropterous, Fig. 18 ), E. Kalimantan , Sotek , 5 km W., 29.xii.1980 , J.Aoki. ( NSMT ) ; 1J (NSMT-I-He-66023, brachypterous), E. Kalimantan , Sotek , 4 km W., 31.xii.1980 , J. Aoki & H. Harada ( NSMT ) . Description. Brachypterous form. Coloration. Body generally fuscous or blackish-brown ( Figs 1, 2 , 5, 6 ). Head and pronotum uniformly blackish-brown ( Figs 1, 2 , 5, 6 ); eye reddishbrown, area surrounding ocellus reddish-brown. Antennae pale yellow, with segment I and base of segment II darkened ( Fig. 5 ). Labium blackish-brown, with apical half of segment III and whole of IV pale yellow ( Fig. 6 ). Scutellum overall black to blackish-brown ( Fig. 5 ). Clavus widely darkened along inner margin and claval commissure; embolium widely darkened along outer margin; cuneus darkened; endocorium narrowly darkened along coriummembrane boundary; membrane greyish transparent; remaining area of hemelytra whitish stramineous ( Figs 5 , 18 ). Trochanters and femora uniformly black to blackish-brown ( Fig. 6 ); tibiae and tarsi pale yellow ( Fig. 6 ). Venter of thorax and abdomen generally black to blackish-brown ( Fig. 6 ). Structure. Body oblong oval, shiny, covered with stramineous setae ( Fig. 5 ). Head smooth, about 0.8 times as long as width across eyes, sparsely covered with long, erect setae intermixed with short reclining setae ( Figs 5, 11 ), and with a longer erect seta on each side of tylus, anteromesal part of each eye, and between eye and ocellus; anteocular portion as long as length of eye in dorsal view; vertex about four times as wide as eye in dorsal view; postocular portion not constricted; eye oblong, not exceeding levels of both dorsal and ventral surfaces of head in lateral view, sparsely covered with short setae. Antennal segment I stout, just reaching apex of head, sparsely covered with short setae ( Figs 5, 11 ); segment II about 0.7 times as long as width across eyes, slightly thickened toward apex, densely covered with suberect setae which are about as long as width of the segment ( Figs 5, 11 ); segments III and IV narrower than basal width of segment II, covered with long erect setae intermixed with short reclining setae, longest seta on segment III more than three times as long as diameter of the respective segment; segment III about as long as segment II; segment IV flattened and longer than segment III. Labium reaching between mesocoxae, sparsely covered with short suberect setae; segment II with long erect setae near base and apex; segment III about twice as long as segment II ( Fig. 6 ); segment IV about 0.7 times as long as segment III ( Fig. 6 ). Pronotum shiny, smooth, nearly trapezoidal, with shallow depression posteromedially ( Figs 5, 11 ), sparsely covered with short stramineous reclining setae, and with long, stout erect setae near anterolateral and posterolateral corners and a pair of similar setae behind ocelli ( Figs 5, 11 ); anterior margin slightly concave, its width a little narrower than mesal length ( Fig. 11 ); lateral margin nearly straight, weakly curved in anterior corner, not carinate; posterior margin shallowly concave, its width about twice as wide as anterior pronotal width ( Fig. 11 ); collar indistinct. Figs 13–16. SEM images of Xylocoris ( Arrostelus ) ampoli Yamada & Yasunaga sp. nov. , male (16) and female (13–15). 13 – ostiolar peritreme and evaporatorium, left lateroventral view; 14 – ostiolar peritreme, left lateroventral view; 15 – supracoxal area, left lateroventral view; 16 – protibia, ventral view. Scale bars: 0.05 mm. Scutellum smooth, nearly equilateral, slightly shorter than basal width, sparsely covered with short reclining setae, and with a pair of very long erect setae near base of lateral side. Hemelytra reaching at most abdominal tergum V (sometimes anterior part of tergum VI), sparsely covered with short stramineous reclining setae and tiny punctures ( Figs 5 , 19 ); costal margin weakly curved ( Figs 5 , 19 ); maximum width of endocorium about 1.8 times width of embolium; cuneal margin about 0.4 times as long as embolial margin; membrane with single weak vein a little remote from outer margin. Ostiolar peritreme without canaliculi, curved forward in middle, not reaching anterior margin of metapleuron ( Figs 13, 14 ). Legs densely covered with stramineous reclining setae; protibiae gradually expanded towards apex, bearing three stout spines on apical half of ventral side, with a well-developed fossula spongiosa at apex ( Figs 16 , 20 ); meso- and metatibiae bearing several stout spines on apical half, the spines a little shorter than width of respective tibia ( Figs 21, 22 ); mesotibia apically with fossula spongiosa smaller than that of protibia ( Fig. 21 ); metatibiae covered with long erect setae on outer side, the longest seta about as long as width of the tibia ( Fig. 22 ). Abdomen beneath covered with stramineous suberect setae, bearing long, stout setae on lateral margin of segments VII and VIII in male; scissure on abdominal tergite reaching near posterior margin of segment III. Figs 17–22. Xylocoris ( Arrostelus ) ampoli Yamada & Yasunaga sp.nov. , male (17, 19–22) and female (18). 17 – head and pronotum, macropterous form, dorsal view; 18 – hemelytron, macropterous form, dorsal view; 19 – ditto, brachypterous form, dorsal view: 20 – right fore leg, outer view; 21 – right middle leg, outer view; 22 – right hind leg, outer view. Scale bars: 0.5 mm for 18, 19; 0.3 mm for 17; 0.2 mm for 20–22. Male genitalia ( Figs 23–27 ). Pygophore shortened, much wider than long, strongly produced laterally on left side, densely covered with short suberect setae on posterodorsal surface, and with several long, stout setae along outer margin ( Figs 23, 24 ); paramere sickle-shaped, arising from left side of posteroventral part of pygophore, with wide groove entirely visible from posterolateral aspect ( Figs 24–27 ); apex of paramere just reaching the tip of laterally produced left side of pygophore ( Figs 23, 24 ). Female genitalia. Abdominal segment VII to IX laterally covered with long, stout setae; ovipositor well devoleped. Measurements (brachypterous form) (J, n = 5 / ♀ , n = 5), value for holotype male in parentheses). Body length 1.90–2.30 (2.10) / 2.05–3.00; head length (excluding neck) 0.30– 0.33 (0.30) / 0.33–0.34; head width across eyes 0.37–0.40 (0.39) / 0.38–0.40; vertex width 0.24–0.25 (0.25) / 0.24–0.27; width between ocelli 0.17–0.19 (0.18) / 0.18–0.20; lengths of antennal segments I–IV: I – 0.13–0.14 (0.13) / 0.13–0.14, II – 0.25–0.29 (0.25) / 0.26–0.29, III – 0.26–0.29 (0.26) / 0.26–0.29, IV – 0.28–0.31 (0.30) / 0.30–0.31; lengths of labial segments II–IV: II – 0.19–0.21 (0.20) / 0.21–0.23, III – 0.38–0.44 (0.40) / 0.43–0.45, IV – 0.29–0.30 (0.29) / 0.30–0.31; anterior pronotal width 0.33–0.34 (0.34) / 0.33–0.36; mesal pronotal length 0.35–0.39 (0.38) / 0.35–0.40; basal pronotal width 0.65–0.75 (0.69) / 0.69–0.71; length of embolial margin 0.54–0.69 (0.55) / 0.58–0.65; length of cuneal margin 0.29–0.33 (0.30) / 0.29–0.33; maximum width across hemelytra 0.71–0.77 (0.74) / 0.71–0.80. Macropterous form . Coloration. General coloration same as brachypterous form, but slightly lighter ( Figs 3 , 7, 8, 12 ). Structure. Almost the same as brachypterous form. Pronotum relatively wider than that of brachypterous form ( Figs 12 , 17 ); anterior pronotal width narrower than mesal length; basal pronotal width about 2.3 times as wide as anterior pronotal width ( Figs 12 , 17 ). Hemelytra much exceeding apex of abdomen in Indonesian specimens ( Figs 7, 8 ), but reaching at most abdominal tergum VIII and remarkably narrowed toward apex in Thai specimens; costal margin nearly straight ( Figs 7 , 18 ); maximum width of endocorium about twice width of embolium ( Figs 7 , 18 ); cuneal margin about 0.6 times as long as embolial margin ( Figs 7 , 18 ). Measurements (macropterous form) (J, n = 4) / ♀ , n = 3)). Body length 2.25–2.55 / 2.55–2.75; head length (excluding neck) 0.31–0.38 / 0.33–0.35; head width across eyes 0.40–0.41 / 0.39–0.44; vertex width 0.25–0.26 / 0.25–0.28; width between ocelli 0.19–0.20 / 0.19–0.20; lengths of antennal segments I–IV: I – 0.13–0.14 / 0.13–0.14, II – 0.29–0.30 / 0.29–0.31, III – 0.28–0.28 / 0.28–0.29, IV – 0.29–0.31 / 0.33–0.34; lengths of labial segments II–IV: II – 0.20–0.23 / 0.20–0.23, III – 0.44–0.44 / 0.46–0.48, IV – 0.29–0.30 / 0.29–0.33; anterior pronotal width 0.34–0.35 / 0.34–0.36; mesal pronotal length 0.38–0.40 / 0.38–0.41; basal pronotal width 0.78–0.84 / 0.74–0.91; length of embolial margin 0.68–0.71 / 0.66–0.78; length of cuneal margin 0.41–0.48 / 0.35–0.45; maximum width across hemelytra 0.80–0.83 / 0.81–0.83. Differential diagnosis. The new species differs markedly from all other members of Arrostellus in its conspicuous color pattern of hemelytra ( Figs 1–3 , 5, 7 , 18, 19 ) and structure of male genitalia ( Figs 23–27 ). Judging from the descriptions and illustrations by GROSS (1954) and CARAYON (1961 , 1972b ), the paramere of the new species differs from those exhibited by other species of Arrostelus in its apex just reaching the tip of laterally produced left side of pygophore ( Figs 23, 24 ) (in others much exceeding the tip of laterally produced left side of pygophore). Xylocoris ampoli sp. nov. is also similar in general appearances to X. vicarius , from which it is separable by the clavus being widely darkened along its inner margin and the claval commissure ( Figs 5, 7 , 18, 19 ) (in X. vicarius wholly darkened except for whitish median part along outer margin) and endocorium being narrowly darkened along corium-membrane boundary ( Figs 5, 7 , 18, 19 ) (in X. vicarius not darkened along corium-membrane boundary). In addition, the shape of ostiolar peritreme and the copulation site on female abdomen of X. vicarius are quite different from the members of Arrostelus ( CARAYON 1972b ). Figs 23–27. Xylocoris ( Arrostelus ) ampoli Yamada & Yasunaga sp. nov. 23, 24 – pygophore with paramere, dorsal (23) and ventral (24) views; 25–27 – paramere, three different aspects. Scale bars: 0.1 mm for 23, 24; 0.05 mm for 25–27. Etymology. The new species is named after Assoc. Prof. P. Ampol (Rajamangala University of Technology, Suvarnabhumi, Ayutthaya , Thailand ) who greatly supported our field researches in Sphan Buri Province of Thailand . Distribution. Thailand ( Suphan Buri Province ), Indonesia (Eastern Kalimantan ). Remarks. Xylocoris ampoli sp. nov. has a wing dimorphism ( Figs 1–3 , 5, 7 , 18, 19 ). The wing dimorphism found in the genus Xylocoris appears to be frequent, especially in the subgenus Arrostelus . Known species of Arrostelus , except for X. queenslandicus , show remarkable wing dimorphism. The hemelytra of the brachypterous form of this new species are almost reaching abdominal tergum V ( Fig. 5 ). On the other hand, the macropterous form is considered to include two types : (1) the hemelytra of the Indonesian specimens are much exceeding the apex of abdomen ( Fig. 7 ); (2) in Thai specimens, the hemelytron reaches abdominal tergum VIII and is remarkably narrowed toward apex. In this paper, we tentatively treat these two types as a single macropterous form because the number of available specimens is currently insufficient to provide an unequivocal definition of the wing variation.