Borysthenes xuzhiae, Lyu, 2025

Lyu, Tianlang, 2025, Taxonomic notes on the genus Borysthenes Stål, 1866 (Hemiptera: Fulgoromorpha: Borysthenidae), with description of six new species from China, Zootaxa 5665 (1), pp. 67-84 : 69-71

publication ID	https://doi.org/10.11646/zootaxa.5665.1.4
publication LSID	lsid:zoobank.org:pub:AE69B232-FCCA-40CC-B6F7-73EA43D06822
persistent identifier	https://treatment.plazi.org/id/03CECD46-6B52-5D4E-FF14-F9D61F3425B7
treatment provided by	Plazi
scientific name	Borysthenes xuzhiae
status	sp. nov.

Treatment

Borysthenes xuzhiae sp. nov.

Fig. 1A–B View FIGURE 1 , 2A–H View FIGURE 2 , 4A–B View FIGURE 4 , 6F–G View FIGURE 6 , 7B View FIGURE 7

Materials examined: Holotype: ♂, Mt. Diaoluoshan , Hainan Island, China (中国¾南ẑ吊 ḄƜ), 23.vii. 2022, leg.: Lyu, Tianlang.

Paratypes: 3♂ 2♀, same data as holotype ; 1♀, same data as holotype, except 24.vii.2022 ; 1♀, same data as holotype, except 25.vii.2021 .

Diagnosis: this species is distinguished by the following combined characters: a) body coloration very dark, b) Tegmina with coastal cell dark-colored except the light-colored narrow strip along Sc+RA, c) male anal segment with both ventrolateral margins moderately extended, length of right margin no more than twice the length of left one, d) aedeagus with the two ventral process sharing a common stalk.

Description. Body length: 7.3–8.0mm (male, n=3), 8.4–9.0mm (female, n=3).

Coloration: Body very dark in general ( Fig. 1A–B View FIGURE 1 , Fig. 6G View FIGURE 6 ). Torso and legs dark brown. Tegmina with all longitudinal veins black, except distal portion of coastal vein and apical one-third of Sc, light brown. Veinlets dark-colored, except ir and second r-m, light brown, and icu, white. Along veins, dark color infiltrate into cells. Specifically, Coastal cell dark except a light narrow strip along Sc+RA, other cells suffused along longitudinal veins and veinlets. Light-colored parts of the cells yellow to light brown.

Structures: Head and thorax: compound eyes well developed. Tegmina with RP and Sc+RA share a common stem, RP with 3 terminals. Hindwing with RP bifurcate.

Male genitalia ( Fig. 2A–H View FIGURE 2 ): Pygofer ( Fig. 2G–H View FIGURE 2 ) generally symmetrical. In lateral view, caudal lateral margins with blunt, subrounded caudal apex; lateral caudal margin with pocket-like extension, from base of ventral process to upper 1/4 of the lateral lobe, folded inward; upper slope of hind margin baring short, inconspicuous setae. In ventral view, medioventral process with sharp apex, about as long as the width at base.

Anal segment ( Fig. 2E View FIGURE 2 ) asymmetrical, subtriangular in dorsal view, about as long as wide. In dorsal view asymmetrical, with left lateral margin extending further caudally than right lateral margin. Two lateroventral extensions with rounded apex, left extension arises after a short distance from base of anal segment, while the right one arises directly from the base of anal segment, corresponding to the asymmetry mentioned above.

Aedeagus ( Fig. 2B–D View FIGURE 2 ) with 5 processes, all visible from ventral view. The left process arises near the apex of periandrium, directed cephalically and curved downward; the right process arises near the apex of periandrium, directed cephalically, curved downward and rightward; two ventral processes share a common stem arising near the apex and directed ventrocephalic, both directed cephalically after diverged from the stem, and gradually separated in ventral view; a short process arises from endosoma, directed ventrocephalic.

Gonostyli ( Fig. 2F View FIGURE 2 ) generally symmetrical, widened towards the apex. From lateral view, apical lobe median, rounded and flat, subapically with angulate prominence. Inner surface covered with dense setae at the level of keel.

Female genitalia ( Fig. 4A–B View FIGURE 4 ): Ovipositor gently curved, gonapophysis IX with dorsal surface smooth. Posterior vagina with caudal portion of both ventral and dorsal walls strongly sclerotized, structure as shown in Fig. 4B View FIGURE 4 . Bursa copulatrix duct dorsocephalad to vagina. Ductus receptaculi cephalad to vagina, not twisted into a helix.

Remarks: By tegmina having coastal cell dark-colored except the light-colored narrow strip along vein Sc+RA, and by aedeagus having two ventral processes sharing a common stem, this species is somewhat similar to B. mysterium sp. nov., which is only found in Mt. Jianfengling Natural Reserve, Hainan Island. This species can be distinguished from the latter by a) tegmina with most longitudinal veins darkened including basal one third of CuA, second m-cu covered in dark (in B. mysterium , base of CuA light-colored, major portion second m-cu light colored), b) caudal margin of male pygofer with blunt apex ( B. mysterium has sharp prominence on caudal margin of male pygofer), c) male anal segment with extension of two lateroventral margins of similar length (in B. mysterium , male anal segment with right lateroventral margin extended ventrally, much longer than the left one), d) aedeagus with an apical process directed leftward (in B. mysterium , no such apical process on aedeagus).

Habitat and behavior: This species was collected in Mt. Diaoluoshan, Hainan Island. It is among the few places on Hainan Island where developed rainforest remains as the dominant vegetation.

At daytime, this species was observed in high density (ca. 10 ind. per m 2), dwelling on the shaded undersurface of large boulders ( Fig. 6F View FIGURE 6 ). They are inactive and easy to capture by hands during daytime.At night, they were found on shrubs and ferns throughout rainforest understory, alert and difficult to capture by hand.

Distribution: Hainan Island (Mt. Diaoluoshan)

Etymology: The specific epithet is a feminine genitive none, a Latinization of a person’s name, dedicated to Ms. Li Xuzhi, the author’s grandmother.