Elasmostethus yunnanus Hsiao & Liu, 1977

Jung, Sunghoon, 2017, Review of the genus Elasmostethus (Hemiptera: Heteroptera: Acanthosomatidae) from the Korean Peninsula, Zootaxa 4320 (2), pp. 351-365 : 361-362

Elasmostethus yunnanus Hsiao & Liu, 1977

Figs. 11, 12, 15, 16, 25–28, 35, 36, 44, 47, 51, 57

Elasmostethus yunnanus Hsiao & Liu, 1977: 161 , 300. Type locality: China: Yunnan, Anning.

Elasmostethus kansuensis (non Hsiao & Liu, 1977: 162, 301): Lee et al. (1994: 29), Kwon et al. (2001: 376). Misidentification. Dichobothrium nubilum (misidentification): Lee (1971: 226, 504) (part) (photo).

Elasmostethus yunnanus: Göllner-Scheiding (2006: 173) (catalogue, distribution), Aukema et al. (2013: 431) (catalogue, distribution).

Diagnosis. Recognized by the presence of a dark, heavily sclerotized and pigmented, dorsocaudally directed median process on the infolding of the ventral rim of the pygophore ( Figs. 44, 47 : mp), and a single median setal tuft below it (Figs. 35, 44, 47); the sinuate lateral margin of the paramere ( Fig. 51 ); and the very deeply excised posterior margin of the eighth abdominal segment of the female (Fig. 36).

Measurements. ♂ / ♀. Body length 9.55–10.62/9.70–11.70; head width across eyes 1.86–1.91/1.78–1.91; lengths of antennal segments: scape 0.66–0.79/0.63–0.88, Basipedicellite 1.24–1.48/1.08–1.31, Distipedicellite 1.12–1.25/1.14–1.23, III 1.47–1.72/1.48–1.71, IV 1.33–1.45/1.12–1.41; humeral width of pronotum 5.25–5.69/ 5.70–6.16; basal width of scutellum 2.80–3.18/3.09–3.15; length of scutellum 3.08–3.65/3.30–3.90; lengths of profemur and protibia 2.11–2.23/1.93–2.64, 2.13–2.29/2.08–2.17; lengths of mesofemur and mesotibia 2.18–2.45/ 2.28–2.63, 2.19–2.42/2.21–2.53; lengths of metafemur and metatibia 2.60–3.10/2.47–3.17, 3.11–3.38/3.00–3.24.

Type material examined. Holotype: ♂, “ Yunnan Anning [printed] \ hot spring [printed] \ 1958 [printed].9.1 [handwritten] \ Cheng Han-Hua [printed]” [all in Chinese script, printed text in red], with red type label ( Figs. 25– 28 ) ( NKUM). Allotype: ♀, “ Beijing Agricultural University Plant Protection Department [printed] \ Kunming Xishan [handwritten] \ 19 [pr] 46-VI-26 [handwritten]”, with type label analogous to that of holotype ( NKUM).

Material examined. SOUTH KOREA: Gangwon-do: Nambuk-ri, Inje-eup, Inje-gun, 14.ix.2014, WG. Kim (1 ♀ CNU); Yongsan-ri, Imgye-myeon, Jeongseon-gun, 7.ix.2011 – 6.x.2011, HW. Byun, JJ. Park, IJ. Heo (12 ♂♂ 7 ♀♀ NIBR); Mt. Gariwang, Hoedong-ri, Jeongseon-eup, Jeongseon-gun, 3.ix.2009, WY. Choi (1 ♀ NIBR); Bukbang-ri, Bukbang-myeon, Hongcheon-gun, 21.viii.2010, HY. Choe (1 ♀ NIBR); Baehu-ryeong, Buksanmyeon, Chuncheon-si, 11.viii.2011, SC. Kim (1 ♂ NIBR); Mt. Chiaksan, Haenggu-dong, Wonju-si, 19.viii.2006, TH. Kang (3 ♀♀ NIBR); Mt. Gariwang, Haanmi- ri, Daehwa-myeon, Pyeongchang-gun, 4.vii.2009 – 28.vii.2009, J.D. Yeo, MJ. Jeon (1 ♀ NIBR). Gyeonggi-do: Yul-dong, Bundang-gu, Seongnam-si, on Aralia cordata Thunb. , 21.ix.2014, WG. Kim (4 ♂♂ 5 ♀♀ CNU); Yul-dong, Bundang-gu, Seongnam-si, on A. cordata Thunb. , 5.x.2014, WG. Kim (1 ♂ CNU); Buk-myeon, Gapyeong-gun, 20.vii.2006, Y. Lee (1 ♀ NIBR). Chungcheongbuk-do: Magok-ri, Bongyang-eup, Jecheon-si, 13.x.2005, TH. Kang (2 ♂♂ 3 ♀♀ NIBR); Mt. Minjuji, Yonghwa-myeon, Yeongdong-gun, 18.v.2011, DG. Kim (3 ♂♂ NIBR). Gyeongsangbuk-do: Bangchongyo, Seo-myeon, Uljin-gun, 22.vii.2010, JW. Lee (1 ♀ NIBR). Gyeongsangbuk-do: Yulsu-ri, Nongam-myeon, Mungyeong-si, on A. cordata Thunb. , 16.x.2014, WG. Kim (1 ♂ 2 ♀♀ CNU); Naeseo-ri, Nongam-myeon, Mungyeong-si, on A. cordata Thunb. (Apiaceae) , 17.x.2014, WG. Kim (2 ♂♂ 2 ♀♀ CNU); Namgok-ri, Euncheok-myeon, Sangju-si, on A. cordata Thunb. , 17.x.2014, WG. Kim (4 ♀♀ CNU). Jeollabuk-do: Gacheon-ri, Gyeongcheon-myeon, Wanju-gun, under bark of Zelkova serrata Makino , 26.iii.2016, WG. Kim (1 ♀ CNU).

Distribution. Korea (new record), China.

Bionomics. This species is widely distributed in South Korea and was collected on various species of Araliaceae and Apiaceae together with E. nubilus and E. rotundus during the present study. This species overwinters as adults.

Remarks. This species is similar to E. brevis , E. humeralis , and E. interstinctus in general appearance but clearly distinguished by the genital segments of both sexes and the parameres of the male. In detail, males of E. yunnanus have a single median setal tuft on the ventral margin of the pygophore, and a heavily sclerotized and pigmented median process on the infolding (Fig. 35, 44, 47); males of the above three species have two pairs of submedian setal tufts on the ventral margin of the pygophore and lack such a process ( Figs. 41–43 ). The posterior margin of the eighth abdominal segment of the female of this species is very deeply emarginate (Fig. 36), while that of the above three species is only weakly emarginate ( E. humeralis , E. interstinctus : Figs. 32, 34, respectively) or slightly protrudes in the middle ( E. brevis : Fig. 30). The paramere of this species is somewhat similar to that of E. humeralis because the distal margin is oblique ( Figs. 50, 51 ), while that of E. brevis and E. interstinctus is nearly perpendicularly truncate distally ( Figs. 48, 49 ); however, the lateral margin of the paramere is sinuate in E. yunnanus ( Fig. 51 ), while it is simple in E. humeralis ( Fig. 50 ).

The scutellum is usually provided with a dark triangular or wedge-shaped median spot and its lateral margins are also darkly suffused at least basally (Figs. 11, 12, 57). Although E. humeralis also frequently has a dark triangular median spot at the base of the scutellum, this spot is always broad and apically rounded (Figs. 9, 10, 56), whilst elongate and apically tapering in E. yunnanus (Figs. 11, 12, 57).

This species was described from Yunnan, Southwest China ( Hsiao & Liu 1977), and subsequently recorded from Songbai Township , Hubei, Central China ( Liu 1979). The identity of the species was confirmed by reexamination of the type material deposited at NKUM . The present record from Korea, representing the first record for the country, considerably extends the known distribution of the species.

Elasmostethus kansuensis Hsiao & Liu, 1977 , was recorded from Korea by Lee et al. (1994) without further remark. The type material of E. kansuensis (holotype, allotype, 2 male and 1 female paratypes from Tianshui, Gansu, China) are deposited in TMNH and were reexamined during the present study; it distinctly differs from all species treated in this paper. Morphologically it is rather similar to E. yunnanus , and the infolding of the ventral rim of its pygophore is also provided with a median process. However, it can easily be differentiated from the latter species by its less produced humeri; the posterior margin of the pygophore being posteriorly broadly produced in the midline to the level of posterolateral angles of segment VII and almost straight at the two sides in ventral view (narrowly produced in the midline, far surpassed by apices of posterolateral angles of segment VII in E. yunnanus ), and the posterior margin of segment VIII of female being weakly arched at the two sides (broadly rounded in E. yunnanus ). No Korean specimen of E. kansuensis could be examined during the present study because we could not find the specimens of E. kansuensis presented in Lee et al. (1994) in any institutions of Korea, and, in addition, there was no further record since the record of Lee et al. (1994). The record of Lee et al. (1994) probably pertains to E. yunnanus .

Figures

FIGURES 41 – 47. Pygophores of Elasmostethus spp. 41 – 46. posterior view; 47. lateral view; 41. E. brevis; 42. E. interstinctus; 43. E. humeralis; 44, 47. E. yunnanus; 45. E. nubilus; 46. E. rotundus. Lettering: ld = lateral denticle; mp = median process; lt = lower setal tuft; ut = upper setal tuft. Scale bars: 0.5 mm.

FIGURES 48 – 53. Right parameres of Elasmostethus spp. 48. E. brevis; 49. E. interstinctus; 50. E. humeralis; 51. E. yunnanus; 52. E. nubilus; 53. E. rotundus. Scale bars: 0.2 mm.

FIGURES 25 – 28. Holotype of Elasmostethus yunnanus and its labels. 25. dorsal view; 26. ventral view; 27. apex of abdomen, posteroventral view; 28. labels. Scale bars: 2 mm.