Genus Orius Wolff, 1811

Orius Wolff, 1811: iv. Type species by monotypy: Salda nigra Wolff, 1811; Zimmerman 1948: 170 (key, note); Wagner 1952: 23 (redescription); Gross 1954: 136 (diagnosis); Herring 1967: 399 (key); Péricart 1967: 148 (diagnosis, discussion); Ghauri 1972: 410 (discussion); Péricart 1972: 160 (redescription); Elov 1976: 372 (diagnosis, key); Herring 1976: 147 (key, figure); Muraleedharan 1977: 233 (diagnosis); Kelton 1978: 46 (diagnosis, key); Muraleedharan and Ananthakrishnan 1978: 8 (key); Ford 1979: 116 (list); Henry 1988: 18 (note); Kerzhner 1988: 770 (key); Lattin and Stanton 1992: 449 (diagnosis, note); Yasunaga 1993: 12 (diagnosis); Cassis and Gross 1995: 33 (catalogue); Péricart 1996: 122 (catalogue); Yasunaga 1997a: 358 (diagnosis, discussion); Hernández and Stonedahl 1999: 548 (diagnosis); Bu and Zheng 2001: 185 (redescription); Yasunaga 2001: 287 (note); Carpintero 2002: 37 (catalogue); Ghahari et al. 2009: 50 (list); Jung et al. 2011: 65 (diagnosis); Aukema et al. 2013: 90 (catalogue); Jung et al. 2013: 424 (catalogue).

Triphleps Fieber, 1860: 266 . Type species by subsequent designation (Kirkaldy 1906: 120): Salda nigra Wolff (Syn. Schumacher 1922: 338); Reuter 1884: 643 (redescription); Distant 1906: 8 (diagnosis); Champion 1900: 326 (note).

Diagnosis

The genus Orius is distinguished from other genera of the tribe Oriini by the combination of following characters: body oval to oblong oval; sexually dimorphic antennae, usually thickened in male; membrane with one to three veins (usually with single visible vein near costal margin of membrane); ostiolar peritreme evenly curved anteriorly, reaching anterior margin of metapleura; male protibia with a row of teeth on ventral side, lacking fossula spongiosa at apex; claws with pulvilli; dorsal laterotergites not fused with mediotergites on abdominal segments II and III; paramere spiral in shape with flagellum and sometimes with denticule on cone; female with developed ovipositor; copulatory tube usually located on intersegmental membrane between VII and VIII. Detailed diagnostic characters and redescription were provided by Wagner (1952), Péricart (1972) and Hernández and Stonedahl (1999).

Remarks

This genus is regarded as an independent group within the Anthocoridae according to recent molecular phylogenetic analyses (e.g. Jung et al. 2010). Morphologically this genus also unequivocally differs from other genera of the Anthocoridae by a combination of the above diagnostic characters; however, any synapomorphy is yet to be clearly suggested for Orius .

Wagner (1952) proposed the subgeneric classification within the genus Orius and divided it into four subgenera, Dimorphella Reuter, 1884; Microtrachelia Blöte, 1929; Orius s. str.; Heterorius Wagner, 1952 . Yasunaga and Miyamoto (1993) added a new subgenus, Paraorius, to accommodate O. tantillus (Motschulsky 1863) . Subsequently, Yasunaga (1997a) described two subgenera, Trichorius and Xylorius, each of which accommodates a single Japanese species. Wagner ’ s subgeneric classification system, generally restricted to the European and East African species, has been used in several taxonomic works (e.g. Péricart 1967, 1972, 1996; Ghauri 1972; Muraleedharan 1977; Yasunaga 1997a, 1997b, 2001; Hernández and Stonedahl 1999). However, several authors who have treated species from other regions ignored the subgenera (e.g. Herring 1966; Woodward and Postle 1986; Bu and Zheng 2001; Postle et al. 2001). To demonstrate more evident subgeneric classification, further comprehensive revision on a global basis would be required. In this paper, we tentatively use Dimorphella Reuter, Heterorius Wagner, and Trichorius Yasunaga, in addition to the nominotypical subgenus, for the classification of Thai species.

Key to species of Orius from Thailand

External characters (without genital structures)

1. Pronotum with long, stout setae near anterolateral and posterolateral corners (Figures 9, 10A) ............................................................................................................................ 2

– Pronotum without long, stout setae near anterolateral and posterolateral corners (Figure 10B – D) ............................................................................................................. 8

2. Head, pronotum and scutellum blackish brown, in clear contrast to mostly yellowish brown hemelytra .................................................................................................... 3

– Body generally dark (blackish brown, greyish brown, dark orange brown)...... 4

3. Body length 1.65 – 1.90 mm (Figure 2E – H); head with shortened neck (Figure 9B); male antennal segment II 0.66 times as long as head width across eyes (Figure 9B); labium pale yellow (Figure 2F, H) ................. O. taksini sp. nov.

– Body length 2.35 – 2.95 mm (Figure 2I – L); head with distinct neck (Figure 9C); male antennal segment II 0.8 times as long as head width across eyes (Figure 9C); labium blackish brown (Figure 2J, L).... .... O. tomokunii sp. nov.

4. Profemora uniformly pale yellow to yellowish brown (Figure 3B, D, F, H, J). 5

– Profemora darkened (Figures 2B, D, 3L). .......................................................................... 7

5. Body generally blackish brown, but hemelytra distinctly paler than pronotum (Figure 3I); male profemora with six fuscous small teeth on ventral side............. ................................................................................................................. O. inthanonus sp. nov.

– Body overall greyish brown to blackish brown or brown to dark orange brown, hemelytra mostly same colour as pronotum (Figure 3A, C, E, G); male profemora without small teeth on ventral side ....................................................................... 6

6. Overall greyish brown to blackish brown, female head pale yellow to yellowish brown (Figure 3A, C); posterior pronotal width 2.2 times as wide as anterior pronotal width (Figure 9D).................................................................. O. fi liferus sp. nov.

– Overall brown to dark orange brown, head somewhat paler anterior to eyes (Figure 3E, G); posterior pronotal width about 2.6 times as wide as anterior pronotal width (Figure 9E)............................................................ O. machaerus sp. nov.

7. Body oblong oval, somewhat parallel sided, generally blackish brown to pitch black (Figure 2A, C); antennal segment II 0.5 – 0.55 times as long as head width across eyes (Figure 9A).................................................................. O. sakaerat sp. nov.

– Body more oval, generally greyish brown (Figure 3K); antennal segment II 0.63 times as long as head width across eyes (Figure 10A)............ O. crassus sp. nov.

8. Pronotal callus usually arched, impunctate, shiny.................................... O. minutus

– Pronotal callus flattened, centrally separated by setigerous punctures (Figures 5M – R, 8A, D, G)............................................................................................................................. 9

9. Head black with pale yellow at apex, labium mostly pale yellow (Figures 4J, L, 5Q, R); hemelytra yellowish brown, cuneus darkened, embolium sometimes posteriorly darkened (Figure 4I, K); profemora without small teeth on ventral side.......................................................................................................................... O. dravidiensis

– Head black, sometimes tinged with orange brown at apex, labium mostly blackish brown (Figure 4B, D, F, H); hemelytra uniformly semitransparent pale yellow or with cuneus apically darkened (Figure 4A, C, E, G); profemora with small teeth on ventral side (Figure 8C, F)...................................................................... 10

10. Hemelytra semitransparent pale yellow, with cuneus apically darkened (Figure 4A, C); anterior area to median furrow in ostiolar peritreme very narrow (Figure 7A)..................................................... ..................................................... O. maxidentex

– Hemelytra uniformly semitransparent pale yellow (Figure 4E, G); anterior area to median furrow in ostiolar peritreme very wide (Figure 7B) O. tantillus

Male and female genitalia

1. Paramere with denticule............................................................................................................. 2

– Paramere without denticule. ................................................................................................... 5

2. Cone wide, strongly rounded, apically obtuse; denticule contiguous to base of flagellum ....................................................................................................................... O. minutus

– Cone very thin, not rounded, apically acute (Figure 14); denticule arising from inner side of cone (Figure 14). ............................................................................................... 3

3. Flagellum straight, with rounded ventral projection near base (Figure 14G); copulatory tube bulbous basally (Figure 19C)............ ............ O. tomokunii sp. nov.

– Flagellum gently curved, without rounded ventral projection near base (Figure 14A, D); copulatory tube tubular basally (Figure 19A, B)............................................................... 4

4. Denticule slender, straight (Figure 14A); copulatory tube with apical membranous section short and rounded (Figure 19A)............................ O. sakaerat sp. nov.

– Denticule small, finger shaped (Figure 14D); copulatory tube with apical membranous section somewhat tubular (Figure 19B)............. ............. O. taksini sp. nov.

5. Pygophore ovoid shaped (Figure 12); cone widened in lateral view, elevated dorsally with weak projection (Figures 15B, C, 16B, C, E, F, 17B, C)........................ 6

– Pygophore globular shaped (Figure 13); cone narrowed apicad in lateral view, not elevated dorsally, without projection (Figure 18B, C, E, F, H, I)........................ 9

6. Flagellum bifurcate (Figure 12D).................................................... O. crassus sp. nov.

– Flagellum not bifurcate (Figure 12A – C) ............................................................................... 7

7. Cone strongly rounded (Figure 15); flagellum filamentous, much longer than four times width of cone (Figure 15) ............................................... O. fi liferus sp. nov.

– Cone moderately curved (Figure 16A, D); flagellum robust and/or sword shaped, not longer than four times width of cone (Figure 16) ................................................. 8

8. Flagellum not expanded basally in lateral view (Figure 16C).. .. O. machaerus sp. nov.

– Flagellum noticeably expanded from base to middle in lateral view (Figure 16F) .................................................................................................................... O. inthanonus sp. nov.

9. Cone obtuse at apex in dorsal view (Figure 18A); lamelliform process present (Figures 18A – C); copulatory tube adjacent to base of ovipositor (Figure 20A) .... ..................................................................................................................................... O. maxidentex

– Cone acute at apex in dorsal view (Figure 18D, G); lamelliform process absent (Figure 18D –, I); copulatory tube remote from base of ovipositor (Figure 20B, C). ............................................................................................................................................................. 10

10. Flagellum tripartite (Figure 18D – F); copulatory tube fused on mesal part of intersegmental membrane between sterna VII and VIII (Figure 20B).. O. tantillus

– Flagellum simple (Figure 18G – I); copulatory tube fused on left part of intersegmental membrane between sterna VII and VIII (Figure 20C)..... ..... O. dravidiensis