Prolygus disciger ( Poppius, 1915 ) Yasunaga & Schwartz & Chérot, 2018

Yasunaga, Tomohide, Schwartz, Michael D. & Chérot, Frédéric, 2018, Review of the plant bug genus Prolygus and related mirine taxa from eastern Asia (Hemiptera: Heteroptera: Miridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 58 (2), pp. 357-388 : 359-362

Prolygus disciger ( Poppius, 1915) comb. nov.

( Figs 1–2 , 12–15 , 24–32 , 45–46 )

Lygus disciger Poppius, 1915: 35 (original description).

Lygus disciger: POPPIUS (1914) : 339 (key); SCHUH (1995): 811 (catalog). Lygocoris (Neolygus) disciger: SCHWARTZ & KERZHNER (1997) : 252 (new combination); LU & ZHENG (1998b):187 (diagnosis, type designation); KERZHNER & JOSIFOV (1999): 114 (catalog).

Neolygus disciger: ZHENG et al. (2004) : 396 (new combination, redescription, key).

Prolygus sp.: YASUNAGA (2001): 260, Fig. 302 (diagnosis).

Type material examined. PARALECTOTYPE: ♁, TAIWAN: Fuhosho, Formosa [currently Nantou County], 7 Sep, H. Sauter ( DEIC, without USIs, image examined).

Additional material examined. JAPAN: KYUSHU: Nagasaki Pref., Nagasaki City, Konoura-Ohgiyama, 32.88, 129.72, UV light trap, T. Nozaki, 1 ♁ ( AMNH _PBI 00380503) ( AMHN). RYUKYUS: Iriomote Island, Shirahama, 24.3645 123.7544, on flower of Pittosporum tobira , 6 Mar 1999, T. Yasunaga, 1 ♀ ( AMNH _PBI 00380504). TAIWAN: HUALIEN: Hsiulin, Hualuhsi, Malaise trap, 22 Nov – 10 Dec 2009, W. T. Yang & K.W.Huang, 1♁ ( NMNS). NANTOU: Mt.Nanren-shan, 22.8417, 120.8358, 13 Mar 2012, Peng & Lan, 1 ♁ ( NMNS). PINGTUNG: Mutan, 22.17477, 120.83560, flowers of Castanopsis indica , 18 Mar 2017, T. Yasunaga et al., 2♁♁ ( TYCN) (1 ♁ with USIs, AMNH _PBI 00380613). TAITUNG: Taimali, Chinlun, UV light trap, 7–8 Dec 2009, W. T. Yang & K. W. Huang, 2 ♁♁ ( NMNS). THAILAND: CHAIYAPHUM: Chulabhomdam, 16.5346, 101.6421, UV light trap, 16 Apr 2013, T. Yasunaga, 1 ♁ ( AMNH _PBI 00380505).

Measurements (Japanese specimens; in mm). ♁ / ♀: Total length of body 3.65 / 3.63; head width including eyes 0.91 / 0.83; vertex width 0.29 / 0.30; lengths of antennal segments I–IV 0.54, 1.62, 0.90, 0.60 / 0.45, 1.35, 0.75, 0.45; labial length 1.47 / 1.35; mesal length of pronotum including collar 0.75 / 0.69; basal width of pronotum 1.20 / 1.20; maximum width across hemelytron 1.40 / 1.44; and lengths of metafemur, tibia and tarsus 1.50, 2.22, 0.56 / 1.35, 1.95, 0.45.

Differential diagnosis. Recognized by pale castaneous to reddish general colouration ( Figs 1–2 , 45–46 ); pale basal part of antennal segment II, except for darkened extreme base; more or less darkened pronotum calli; often darkened inner parts of clavus and corium; distinct, triangular pygophoral spine ( Figs 14 , 24 ; PS); C-shaped left paramere with an elongate median process and small ventral process on hypophysis ( Figs 24–26 ); flattened, apically inflated right paramere ( Fig. 27 ); presence of two distinct lobal-sclerites (PL, SL), a basal spicule (SP), and a spinulate (TL) sclerite on endosoma ( Figs 28–30 ); rather narrow interramal lobe ( Fig. 31 ); and thick-rimmed, elongate ovoid sclerotized ring ( Fig. 32 ). This species is most closely related to P. papuanus , from which P. disciger can be distinguished by generally reddish body (in live or freshly preserved specimens); faint or weak paired spots on pronotal calli; uniformly creamy yellow coxae; shorter, more bulbous right paramere with blunttipped hypophysis; left paramere with a elongate apical process; endosoma with a basal spicule ( Fig. 29 , SP); and narrower, subtriangular interramal lobe ( Fig. 30 ).

Biology. A female adult was collected by sweep-netting flowers of Pittosporum tobira (Thunb.) W.T. Aiton (Pittosporaceae) that is distributed widely in warm climate zones of SW Japan; a few adults were found on Castanopsis indica (Roxb. ex Lindl.) A.DC. (Fagaceae) in Taiwan ( Fig. 1 ). Similar to P. nigriclavus , this species prefers to inhabit (and feed on) inflorescence of broadleaf trees.

Distribution. Japan (Kyushu: Nagasaki, Ryukyus: Iriomote Island) ( YASUNAGA et al. 2001; new record from Nagasaki), P. R. China (Guangdong, Yunnan) ( LU & ZHENG 1998b), Thailand (Chaiyaphum) (new record), Taiwan (Hualien, Nantou, Pingtung, Taitung) ( POPPIUS 1915 and additional records). In Taiwan this mirid occurs widely in mountain areas to coastal zones.

Comments. Based on the elongate body form, distinctly sutured (or keeled) clavus and presence of pygophoral spine (PS, cf. Fig. 24 ), this taxon is doubtlessly placed in Prolygus . LU & ZHENG (1998b) and ZHENG et al. (2004) provided a redescription, including the male genitalia, of this species placed in the genus Neolygus . The male genitalic structures illustrated by LU & ZHENG (1998b) are similar to those possessed by P. papuanus rather than Neolygus members. The following particular features that diagnose Neolygus are not found in P. disciger : left paramere with apical portion of sensory lobe strongly protuberant and shaft without subapical process; endosoma including a loop sensu CLAYTON (1982), and a wide spicule. Among a pair of syntypes present, LU & ZHENG (1998b) designated a female (deposited in MZHF, without antenna and left forewing) as the lectotype instead of the male (in DEIC). Because the redescription (including the male genitalia) by LU & ZHENG (1998b) was based on non-type specimens from continental China, we have some doubt whether all of those continental specimens are conspecific with the male paralectotype from Taiwan. One male specimen collected in Thailand most probably fits this species, but the shape of its endosomal sclerites is slightly different from Japanese and Taiwanese specimens, probably representing tiny but recognizable geographical variation.

Figures

Figs 1–11. Habitus images of genuine Prolygus species, live individuals. 1–2 – P. disciger (Poppius, 1915) (1 –♁, Pingtung, Taiwan; 2 –♁, Chaiyaphum, Thailand), 3–5 – P. papuanus (Poppius, 1915) (3 – ♀, attracted to FL light in Brastagi, N. Sumatra; 4–5 – ♁, Kathmandu, Nepal), 6–11 – P. nigriclavus (Poppius, 1915) (6 – ♁, Kathmandu; 7 – ♀, Nakhon Ratchasima, Thailand; 8 – ♁, darkened individual, Nantou, Taiwan; 9–11 – reared ♁ emerging, Rasuwa, Nepal).

Figs 12–23. Scanning electron micrographs for genuine Prolygus species. 12–15 – P. disciger (Poppius, 1915), ♁: 12 – dorsal surface, 13 – cuneus and metatarsi, 14 – apical part of pygophore, left lateral view, 15 – scent efferent system; 16–17 – P. nigriclavus (Poppius, 1915), ♀: 16 – head and thorax, left lateral view, 17 – pretarsus (hind leg); 18–23 – P. papuanus (Poppius, 1915): 18 – ♀, dorsal surface, 19 – ♁, head and thorax, left lateral view; 20 – ♀, pretarsus (hind leg); 21 – ♀, dorsal vestiture (c: corium, p: pronotum, s: scutellum), 22 – ♁, apex of pygophore, left lateral view, 23 – ♁, metatarsus.

Figs 24–32. Male (24–30) and female (31–32) genitalia of Prolygus disciger (Poppius, 1915). 24 – pygophoral spine and left paramere; 25–26 – left paramere; 27 – right paramere; 28–30 – endosoma; 31 – posterior wall; 32 – bursa copulatrix. Scale bars 0.2 mm.

Figs 43–53. Habitus images of genuine Prolygus spp, dry-preserved specimens in dorsal and ventral (46, 53) view. 43–44 – P. alboscutellatus Carvalho, 1987:43 –♀ (N. Sumatra); 44 –♁ (Negros, Philippines).45–46 – P. disciger (Poppius, 1915):45 –♀ (Iriomote Island, Japan), 46 –♁ (Pingtung, Taiwan); 47 – P. loriae (Poppius, 1914), holotype, ♁ (ZMUF); 48 – P. nigriclavus (Poppius, 1915) (N. Sumatra); 49 – P. palauensis (Carvalho, 1956), holotype, ♁ (USNM); 50–53 – P. papuanus (Poppius, 1914): 50 – ♁ (Perak, Malaya), 51 – ♁ (N. Sumatra), 52–53 – ♀ (N. Sumatra).