Perissonemia okinawensis sp. nov.

(Figs 1C, D, 2C, D, 3B, 4B, 5B, 6B, 7B, 8B, E, 9B, E)

Perissonemia occasa (misidentification): AZUMA & KINJO (1987): 34 (checklist: Okinawa Prefecture); HAYASHI (2002): 137 (checklist: Ryukyu Islands).

Type series. HOLOTYPE: ♂ (ELKU), “[JAPAN]: the Ryukyus, Okinawa Isls., Okinawa Honto Is., Kunigami-son, Yona” [= JAPAN: RYUKYU ISLANDS (central part): Okinawa Group: Okinawa Island: Kunigamison, Yona], 26.iv.2021, leg. K. Saito. PARATYPES (4 ♂♂ 4 ♀♀), JAPAN: RYUKYU ISLANDS (central part): Okinawa Group: Okinawa Island: Mt. Oppadake, 30.vi.1992, leg. M. Hayashi (1 ♂ 1♀, TUA); as holotype (1 ♂ 1 ♀, ELKU); Higashi-son, Takae, 6.vi.2019, leg. H. Yoshitake (1 ♀, NIAES). Geruma Island: 10.viii.1977, leg. S. Azuma (2 ♂♂ 1 ♀, NSMT – referring to AZUMA & KINJO 1987, as P. occasa).

Diagnosis. Recognized among other species of Perissonemia by a combination of the following characters: body length 3.0– 3.5 mm (Figs 1C, D, 2C, D); pronotal disc, posterior process and hemelytron except for areolae brown; frontal and median spines distinct (Fig. 3B); occipital spine reaching middle part of compound eye; buccula with 3 rows of areolae at highest part; rostrum reaching beyond posterior margin of mesosternum (Fig. 7B); lateral carina of pronotum present on pronotal disc and posterior process (Fig. 4B); costal area of hemelytron 0.5 times as wide as subcostal area at widest part of each, with a single row of areolae throughout its length (Fig. 5B); subcostal area less than 0.5 times as wide as discoidal area at widest part of each, with 3 rows of areolae at apex and 2 rows in remaining parts (Fig. 6B); discoidal area with 6 rows of areolae at widest part; sutural area with 7 rows of areolae at widest part; and anterior margin of pygophore weakly concave in middle part of dorsum (Fig. 9B).

Description. Male. Head, antennae, bucculae, pronotum, hemelytra except for most of areolae, legs and ventral surface brown; compound eye dark red; areolae of hemelytron except for sutural area translucent; pubescence on body yellowish (Figs 1C, 2C, 3B, 4B, 5B, 6B, 7B, 8B).

Body 3.3 times as long as maximum width across hemelytra (Fig. 1C). Head (Figs 3B, 4B, 7B) covered with pubescence; pair of frontal spines distinct, touching each other at apices, reaching apex of clypeus; median spine distinct, as long as frontal spines, reaching beyond bases of frontal spines; pair of occipital spines longer than median spine, reaching middle part of compound eyes; antenniferous tubercles obtuse, slightly curved inward; clypeus smooth. Compound eye round in dorsal view. Antenna covered with pubescence; segment I cylindrical; segment II conical, shortest among antennal segments; segment III longest among antennal segments; segment IV cylindrical, longer than segment I. Buccula with 3 rows of areolae throughout its length. Rostrum reaching beyond posterior margin of mesosternum.

Pronotum (Figs 3B, 4B) 1.5 times as long as maximum width across humeri, glabrous. Pronotal disc coarsely punctate. Hood absent. Calli smooth, partly covered with wax. Collar with 2 rows of areolae throughout its width, with anterior margin slightly curved laterad. Pronotal carinae without distinct areolae. Median carina straight, extending to apex of posterior process. Lateral carina present on pronotal disc and posterior process. Posterior process triangular, obtuse at apex.

Hemelytron (Figs 2C, 5B, 6B) 2.7 times as long as its maximum width, extending beyond apex of abdomen, glabrous; maximum width across hemelytra 1.1 times as long as maximum width across humeri; costal area 0.5 times as wide as subcostal area at widest part of each, with single row of areolae throughout its length; subcostal area less than 0.5 times as wide as discoidal area at widest part of each, with 3 rows of areolae at apex and 2 rows in remaining parts; discoidal area with 6 rows of areolae at widest part; sutural area with 7 rows of areolae at widest part.

Thoracic pleura (Fig. 2C) coarsely punctate. Prosternum (Fig. 7B) narrower than mesosternum. Sternal laminae lower than bucculae; anterior and posterior margins lower than lateral margin; prosternal lamina nearly straight, lower than mesosternal lamina; mesosternal lamina as high as metasternal lamina. Legs (Fig. 1C) smooth, covered with pubescence; femora thickest in middle.

Abdomen oblong in dorsal and ventral views. Pygophore (Figs 8B, 9B) compressed dorsoventrally, hexagonal in ventral view, covered with pubescence; anterior margin weakly concave in middle part of dorsum. Paramere (Fig. 9E) expanded in middle part, angularly curved inward in apical part; outer and inner margins covered with pubescence in middle part.

Measurements (n = 5). Body length with hemelytra 3.0– 3.5 mm; maximum width across hemelytra 0.9–1.1 mm; length of antennal segments I to IV 0.2 mm, 0.1 mm, 0.9–1.1 mm, and 0.3 mm, respectively; pronotal length 1.2–1.4 mm; pronotal width across humeri 0.8–1.0 mm; hemelytral length 2.1–2.4 mm; maximum width of hemelytron 0.8–0.9 mm.

Female. General appearance very similar to that of male (Figs 1D, 2D, 8E) except for the following characters: body 3.2 times as long as maximum width across hemelytra; antennal segment III shorter than in male; hemelytron 2.8 times as long as its maximum width; maximum width across hemelytra 1.2 times as long as maximum width across humeri; terminalia pentagonal in ventral view.

Measurements (n = 4). Body length with hemelytra 3.3–3.5 mm; maximum width across hemelytra 1.0– 1.1 mm; length of antennal segments I to IV 0.2 mm, 0.1 mm, 0.8–0.9 mm, and 0.3 mm, respectively; pronotal length 1.4 mm; pronotal width across humeri 0.9–1.0 mm; hemelytral length 2.4–2.5 mm; maximum width of hemelytron 0.9–1.0 mm. Differential diagnosis. Among the East Asian species, Perissonemia okinawensis sp. nov. is most similar to P. borneensis in morphological characteristics. However, based on a comparison between the type material of the new species and the photographs of the syntype (NATURAL HISTORY MUSEUM 2014), together with the original description (DISTANT 1909) of P. borneensis, two main characteristics were recognized to easily differentiate P. okinawensis sp. nov. from P. borneensis: body length 3.0– 3.5 mm (Figs 1C, D, 2C, D) (4.0 mm in P. borneensis); and pronotal disc, posterior process and hemelytron except for areolae brown (black in P. borneensis). Moreover, morphological differences between the new species and the other Japanese species are provided in the identification key below.

Etymology. The specific epithet refers to its occurrence in Okinawa Group, the central part of the Ryukyu Islands, Japan; an adjective.

Host plant. Unknown. More field surveys focusing on evergreen oleaceous trees are needed, especially on those of the genus Osmanthus .

Biology. Adults were collected in April, June, and August. Nymph is unknown.

Distribution. Japan (Ryukyu Islands (central part): Okinawa Group: Okinawa Island, Geruma Island) (Fig. 11) (AZUMA & KINJO 1987, HAYASHI 2002).

Although the specimens could not be examined, the previous record of “ Perissonemia occasa ” from Aka Island, Okinawa Group, the central part of the Ryukyu Islands (AZUMA & KINJO 1987) can correspond to the new species. Perissonemia okinawensis sp. nov. inhabits the laurilignosa in the subtropical climate of the central part of the Ryukyu Islands.