Randallopsallus Yasunaga, 2013

Yasunaga, Tomohide, Duwal, Ram Keshari & Jsps, 2017, Two new species of the phyline plant bug genus Randallopsallus from Southeast Asia (Hemiptera: Heteroptera: Miridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57 (2), pp. 457-471 : 458-462

Genus Randallopsallus Yasunaga, 2013

Randallopsallus Yasunaga, 2013:197 (gen.nov.). Type species by original designation: Randallopsallus paracastaneae Yasunaga, 2013 .

Randallopsallus: SCHUH & MENARD (2013) : 21 (tribal placement in Exaeretini ).

Diagnosis. Recognized by moderate size (2.9–3.5 mm in total length); ovoid, rather tumid, always macropterous body form ( Figs 1, 6 , 9, 11 ); dark brown or castaneous basic coloration; dorsal vestiture with uniformly distributed, brownish, reclining (common) setae, intermixed with moderately or rather sparsely distributed, silvery, sericeous, appressed setae; head across eyes broader than height in frontal view ( Figs 18–21 ); antennal segment IV longer than III; long, stout labium slightly exceeding apex of metacoxa; short, scalelike setae (that are uniformly scattered and not partly aggregated) on thoracic pleura and abdominal sterna ( Figs 7, 10, 14–17 , 48, 51 ); thickened or roundly produced margin of ostiole ( Figs 14–17 ); fleshy, somewhat lanceolate, apically convergent parempodia ( Figs 25–27 ); more or less splayed-out left paramere ( Figs 30, 33 ); tumid, elongate-oval right paramere ( Figs 29, 33 ); apically folded or keeled phallotheca ( Figs 31, 34 ); J-shaped, broad endosoma with well-developed secondary blade ( Figs 32, 35 ); thick-rimmed secondary gonopore; rather toughened bursa copulatrix ( Figs 36, 41, 45 ); posterior wall with relatively clear interramal sclerite ( Figs 40, 42, 44 ); developed medioventral extension of ventral labiate plate ( Figs 39, 43, 46 ). See YASUNAGA (2013) for more detailed diagnostic characters.

Distribution. Now known widely in the central Oriental Region, ranging from Indochina ( Thailand) to the Sundaland (Peninsular Malaysia and Sumatra).

Discussion. Randallopsallus can be separated from any other phyline genera by the distinctive male genitalic structures, particularly strongly bifurcate endosoma, in spite of presence of other features in Randallopsallus (cf. Figs 2–5 ) that cause it to superficially resemble members of genera placed within other tribes of Phylinae . YASUNAGA (2013) mentioned that the similarity in appearance of this taxon with the large Holarctic genus Psallus Fieber, 1858 (cf. Fig. 5 , Psallus edoensis Yasunaga & Vinokurov, 2000 ) is considered only superficial. SCHUH & MENARD (2013) placed Randallopsallus in the tribe Exaeretini based on the possession of lamellate parempodia (cf. Fig. 63 ) and the elevated posterior process of the left paramere, which are shared by some genera in the Exaeretini (e.g., Opuna Kirkaldy, 1902 ; Moissonia ).

Nonetheless, we now consider that Randallopsallus most probably belongs to the tribe Pilophorini . This tribe is known to comprise morphologically very diverse taxa. Some members of Pilophorus Hahn, 1826 are strikingly antlike because of a conspicuous modification of the pronotum or scutellum (see SCHUH 1989, 1991; YASUNAGA & SCHUH 2013; YASUNAGA et al. 2016). In Chimairacoris Yasunaga, Schuh & Cassis, 2015 , the external appearance is reminiscent of a certain deraeocorine or termatophyline mirid ( Deraeocorinae ) rather than phylines (YASUNAGA et al. 2015, YASUNAGA & DUWAL 2017). Therefore, morphological features in the Pilophorini may be even more variable than in other phyline tribes.

The following characters in Randallopsallus are shared by several pilophorine genera: ovoid, tumid body with broad head (cf. Hypseloecus Reuter, 1891 as in Figs 2–3 , Parasthenaridea Miller, 1937 ); vestiture on body surface with brownish, simple setae intermixed with sericeous or scalelike setae that are uniformly distributed and neither aggregated nor striped ( Lasiolabops Schuh, 1984 [ Fig. 55 ]; Parasthenaridea ; Stheneridea Reuter, 1885 [ Fig. 4 ]); long, stout labium ( Parasthenaridea ); left paramere more or less splayed-out ( Druthmarus Distant, 1909 , Hypseloecus , Pherolepis Kulik, 1968 , Pilophorus , cf. Figs 58, 60 ); C- or J-shaped, stout endosoma with apically situated, heavy-rimmed gonopore ( Chimairacoris [see YASUNAGA & DUWAL 2017], Lasiolabops [see SCHUH 1984]); and developed, bifurcate medioventral extension of ventral labiate plate ( Figs 39, 43, 46 ) ( Hypseloecus , Fig. 47 ). Based on these characters, in addition to the lamellate, apically convergent parempodia (cf. Figs 54 , 56, 59 ) that are possessed commonly by pilophorines as well as quite a few taxa of other phyline tribes (e.g., Decomiini [ Fig. 61 ], Exaeretini [ Fig. 63 ], Nasocorini [ Fig. 62 ]; as documented by SCHUH (1984), pretarsus often with setiform parempodia and enlarged flabellate pulvillus on the interior surface of the claw), we presume that Randallopsallus should belong to the Pilophorini and has the closest relationship to Parasthenaridea (known only from Peninsular Malaysia) (see SCHUH 1984). SCHUH (1974) suggested that the form of the posterior wall is distinctive for the Pilophorini , with the posterior margin of the wall being distinctly evaginated. However, we did not recognize the feature pointed out by SCHUH (1974) in Randallopsallus (cf. Figs 40, 42, 44 ). A definitive systematic position of Randallopsallus further requires the acquisition of DNA sequence data and biological information.

Three congeners are revealed to occur in Indochina and western Sundaland ( Fig. 64 ). The current distribution of Randallopsallus is restricted to the tropical part (between the equator and the 15th parallel north) along the 100th meridian east in the Oriental Region. Needless to say, our previous fieldwork is insufficient, and further surveys in broader areas will probably yield additional data. All available specimens of Randallopsallus were collected only by UV light traps; they are assumed to inhabit forest canopy as supposed for some Hypseloecus species (YASUNAGA et al. 2015).

Figures

Figs 1–6. Habitus images of phyline plant bugs, live adult individuals. 1 – Randallopsallus paracastaneae Yasunaga, 2013 (all attracted to UV light trap) (SERS, Thailand), 2–3 – Hypseloecus castaneus Yasunaga, Yamada & Artchawakom, 2015 (2 – J, Chaiyaphum, Thailand; 3 – ♀, Nakhon Nayok, Thailand), 4 – Sthenaridea piceonigra (Motschulsky, 1863) (J, Yangon, Myanmar), 5 – Psallus edoensis Yasunaga & Vinokurov, 2000 (♀, Tokyo, Japan).

Figs 6–17.Habitus images of Randallopsallus spp. (6, 9, 10 – dorsal, 7, 8, 12–13 – ventral, 14–17 – left lateral views). 6–8, 14 – R. malayanus sp. nov. 9–10, 15 – R. berastagi sp. nov. 11–13, 16–17 – R. paracastaneae Yasunaga, 2013.

Figs 18–27. Randallopsallus spp., head in frontal view (18–21), scent efferent system (22–24), and pro- (27), meso- (26) and metatarsus (25). 18, 19, 22, 25 – R. malayanus sp. nov.; 20, 23, 26 – R. berastagi sp. nov.; 21, 24, 27 – R. paracastaneae Yasunaga, 2013.

Figs 48–54. Scanning electron micrographs for Randallopsallus spp. 48–50 – R. berastagi sp. nov., ♀: 48 – head and thorax, left lateral view, 49 – thoracic pleura and scent efferent system, 50 – metatarsi; 51–54 – R. paracastaneae Yasunaga, 2013, ♀: 51 – head and thorax, left lateral view, 52 – thoracic pleura and scent efferent system, 53 – metatarsi, 54 – pretarsus of foreleg.

Figs 28–35. Randallopsallus spp., male genitalia. 28–32 – R. paracastaneae Yasunaga, 2013: 28 – pygophore in dorsal view, 29 – right paramere, 30 – left paramere, 31 – phallotheca, 32 – endosoma; 33–35 – R. malayanus sp. nov.: 33 – apex of pygophore in dorsal view, 34 – phallotheca, 35 – endosoma.

Figs 36–47. Randallopsallus spp. and Hypseloecus castaneus Yasunaga, Yamada & Artchawakom, 2015, female genitalia: 36–40 – R. berastagi sp. nov.: 36 – bursa copulatrix in dorsal view, 37 – ditto in ventral view, 38 – sclerotized ring, 39 – medioventral extension of ventral labiate plate, 40 – posterior wall; 41–43 – R. malayanus sp. nov.: 41 – bursa copulatrix in dorsal view, 42 – posterior wall, 43 – medioventral extension of ventral labiate plate; 44–46 – R. paracastaneae Yasunaga,2013:44 – posterior wall, 45 – bursa copulatrix in dorsal view, 46 – medioventral extension of ventral labiate plate; 47 – Hypseloecus castaneus: bursa copulatrix in dorsal view. Scale bars 0.2 mm.

Figs 55–63. Scanning electron micrographs for Asian phylines. 55–56 – Lasiolabops cosmopolites Schuh, 1984,J: 55 – head and thorax, left lateral view, 56 – pretarsus (hind leg); 57–58 – Pilophorus lucidus Linnavuori, 1962, J: 57 – scent efferent system, left lateral view, 58 – abdomen, left lateral view; 59–60 – Pilophorus typicus (Distant, 1909), J: 59 – pretarsus (hind leg), 60 – left paramere, left lateral view; 61 – Decomia indochinensis Schuh, 1984 (Decomiini), pretarsus (hind leg); 62 – Campylomma livida Reuter, 1885 (Nasocorini), pretarsus (hind leg); 63 – Moissonia punctata (Fieber, 1861) (Exaeretini), pretarsus (hind leg).

Fig. 64. Distribution map for species of Randallopsallus.