Physatocheila euthenia Souma & Ishikawa 2022, comb. nov.

Physatocheila euthenia (Drake & Ruhoff, 1965), comb. nov.

(Figs. 8D, 9D, 10D, 11D, 17F, 18F)

Cysteochila euthenia Drake & Ruhoff, 1965b: 254. Holotype: macropterous ♂, Malaysia: Sabah (N. Borneo), Tenompok; BPBM.

Cysteochila euthenia: Péricart (1985a: 48) (distribution); Guilbert (2015: 536) (distribution).

Specimens examined. Non-types (4 ♂♂ 1 ♀), JAPAN: Ryukyu Islands: Yaeyama Islands: Okinawa, 23.xi.1960, leg. K. Yasumatsu (1 ♂, ELKU); Iriomote Is., Sonai, 8.x.1963, leg. K. Morimoto (1 ♀, KUM); Iriomote Is., Hoshidate, 27.iii.1991, leg. M. Hayashi et al. (1 ♂, NSMT); as above but 30.iii.1996 (2 ♂♂, TUA). A single specimen deposited in ELKU is labeled “ Cysteochila yasumatsui Takeya, 1962 ” (manuscript name).

Diagnosis. Recognized among other species of Physatocheila by a combination of the following characters: general color ashen (Figs. 8D, 9D, 10D); median spine on head extending beyond bases of frontal spines; rostrum reaching middle part of metasternum; pubescence on pronotum more than 0.5 times as long as diameter of compound eye; lateral carinae of pronotum close to each other in anterior part, concealed by paranotum in anterior part; paranota completely covering pronotal disc in anterior part, not touching each other, not concealing median carina of pronotum, widened posteriorly, bulged upward in posterior part, forming a cyst; cyst of paranotum concave in posterior part; outer margin of paranotum gently curved outward in its entire length; costal area of hemelytron wider than subcostal area at widest part, more than 0.5 times as wide as discoidal area at widest part, with 2 rows of areolae in its entire length; and subcostal area subvertical, with 2 rows of areolae in its entire length.

Description of genitalia. Pygophore (Figs. 10D, 17F) compressed dorsoventrally, semicircular in ventral view, strongly concave at anterior margin of dorsum, elevated at center of venter, smooth on surface, irregularly punctate in middle part of dorsum. Paramere (Fig. 18F) expanded in middle part, curved inward in apical part; outer and inner margins covered with pubescence in middle part. Female terminalia (Fig. 11D) pentagonal in ventral view, covered with pubescence.

Remarks. This species belongs to Physatocheila without doubt because of the presence of generic characteristics, as described in the Diagnosis section. Therefore, the new combination, Physatocheila euthenia (Drake & Ruhoff, 1965) comb. nov., is proposed.

The aforementioned specimens match the illustration (http://n 2t.net/ark:/65665/369f879a9-f75d-467b-b4c9- 6269c9c8361f) and the original description (Drake & Ruhoff 1965b) of P. euthenia comb. nov. described from Malaysia, with the exception of the rostrum reaching the middle part of the metasternum. Because it is currently unclear whether the difference in the length of the rostrum indicates a difference at the species level or reflects infraspecific variation within the same species, the Japanese population is provisionally identified as P. euthenia comb. nov.

Physatocheila euthenia comb. nov. resembles P. fieberi in the shape of paranotum but can be easily distinguished from the latter by the following characteristics: general color ashen (Figs. 8D, 9D, 10D); pubescence on pronotum more than 0.5 times as long as diameter of compound eye; costal area of hemelytron more than 0.5 times as wide as discoidal area at widest part.

Distribution. Japan (Ryukyu Islands: Okinawa Island?, Iriomote Island), Malaysia (Borneo Island), Nepal, Vietnam.

Physatocheila euthenia comb. nov. was recorded in Japan for the first time. Discovery of the P. euthenia comb. nov. from the Iriomote Island represents the northernmost distributional record of this species.

The notation “Okinawa” in the label of a single specimen deposited in ELKU likely refers to the Okinawa “Prefecture” (an administrative area), which includes a number of islands, and not the Okinawa “ Island ” (an island). Therefore, whether P. euthenia comb. nov. was recorded on the Okinawa Island remains unclear.

Host plant. Unknown.

Biology. In Japan, adults were observed in October, November, and March (the present study). Conversely, adults were collected from September to February in other distribution areas (Drake & Ruhoff 1965b; Péricart 1985a; Guilbert 2015).