Syncosmetus wuliangensis sp. nov.

Figs. 1–8

Chinese vernacular name: ƮḆğ木ϕφ

Type material. HOLOTYPE: CHINA: male, “China: Yunnan, Dali Bai Autonomous Prefecture, Nanjian County, Wuliang Mountain, 24°45′1″N, 100°30′11″E, 2350 m, 03.viii.2020, leg. Ji-Shan Xu, Da-Rui Mo & Juan Shao” . PARATYPES: CHINA: 2 males, same data as the holotype .

Diagnosis. This species differs from all known Syncosmetus species by pronotum lacking a sulcus at longitudinal midline (present in all known species); sides of pronotum narrow, barely visible from above; first and second longitudinal keels united close to elytral base; second and third keels united at their apices (in Sy. japonicus, first and second keels united, second and third keels not united; in Sy. euryale, Sy. medusa and Sy. stheno, first, second and third keels not united; in Sy. perseus, first and second keels not united, second and third keels united).

Description. Male (Figs. 1–8). Fully pigmented adult (hind legs lost), measurements in mm: TL 1.52, PL 0.62, PW 0.75, EL 0.87, EW 0.97, GD 0.81. Ratios: PL/PW 0.83, EL/EW 0.90, EL/PL 1.40, GD/EW 0.84, TL/EW 1.57. Body rounded, extremely convex, mostly blueish black; antennae, palpi and legs brownish yellow; dorsal with minute setae, ventral with minute setae as long as dorsal. Head with several minute setae; punctation coarse and shallow, the surface between punctures microreticulate; vertex with a median knob. Antennae (Fig. 4) bearing ten antennomeres with the following lengths (in mm, right antenna measured): 0.09, 0.04, 0.04, 0.03, 0.02, 0.02, 0.02, 0.03, 0.04, 0.06 (FL 0.13 mm, CL 0.13 mm, CL/FL 1.00). Compound Eyes coarsely facetted, each bearing approximately 30 ommatidia; GW 0.11 mm. Pronotum with coarse and deep punctures bearing minute setae; the surface between punctures microreticulate (best seen in lateral view); longitudinal midline without a sulcus; anterior edge broadly rounded; sides explanate but usually narrow, weakly crenulate, barely visible from above; posterior edge with coarse and shallow punctures. Scutellar shield very small, barely discernible; BW 0.03 mm. Elytra tightly locked but not fused, punctation coarse and deep, without minute setae, and the surface between punctures smooth; each elytron with four longitudinal keels (excluding the median keel), bearing thin and sparse setae; each elytron with first longitudinal keel extending to about the middle of elytral edge; first and second keels united close to elytral base; second and third keels united at their apices (Fig. 2, arrow). Prosternum in front of coxae biconcave, without punctures, wrinkled, extremely tumid at middle, bearing a longitudinal carina; sides with thin and long setae; prosternal process laminate, extending to posterior edge of procoxal cavity. Mesoventrite in front of coxae biconcave, with thin and long setae; mesoventrital process extending to half the length of mesocoxal cavity. Metaventrite tumid at middle, bearing a longitudinal carina; punctation shallow at longitudinal carina; sides with deep and rounded punctures, bearing minute setae. Protibia not expanded, three times as long as broad; inner margin with a conspicuous tuft of long bristles at the apical third; apical edge with a row of spines. Meso- and metatibia (Fig. 5, right hind leg of a holotype) not expanded, five times as long as broad; outer edge with several sparse spines; apical edge with a row of spines and several setae. Abdominal ventrites with coarse punctures, concentrated at the anterior portion of each ventrite; abdominal ventrites I–II with punctation visible and abdominal ventrites III–V with punctation barely visible, length of the ventrites (in mm) as follows: 0.22, 0.06, 0.05, 0.07, 0.15; first abdominal ventrite bearing a circular, weakly margined setose sex patch at its center, with a transverse diameter of 0.02 mm. Male abdominal terminalia in a paratype (Figs. 6–8) (sternite VIII damaged during dissection, so not described): Tegmen (Fig. 7) long, rounded apically, with a pair of processes in the apical third, and subparallel laterally in basal two-thirds. Penis (Fig. 8) flat, sclerotized laterally, membranous in the middle.

Female. Unknown.

Measurements. Males (n = 3, including the holotype; in mm): TL 1.52–1.78 (1.63 ± 0.11); PL 0.62–0.67 (0.64 ± 0.02); PW 0.75–0.84 (0.79 ± 0.04); EL 0.87–1.07 (0.97± 0.08); EW 0.97–1.13 (1.03 ± 0.07); GD 0.81–0.97 (0.89 ± 0.07). Ratios: PL/PW 0.80–0.84 (0.82 ± 0.02); EL/EW 0.90–0.96 (0.93 ± 0.03); EL/PL 1.40–1.60 (1.50 ± 0.08); GD/EW 0.84–0.88 (0.86 ± 0.02); TL/EW 1.57–1.84 (1.73 ± 0.12).

Distribution. Wuliang Mountain, Yunnan, China.

Host fungi. Unidentified Polyporaceae .

Etymology. The specific name ‘ wuliangensis’ is taken from the type locality, Wuliang Mountain.