Holotype. China – Hubei Prov. • ♂; glued on a card with two labels as follows: “China: Hubei Prov., Baokang County, Cuijia’ao, 31.72°N, 111.13°E, alt. 1550 m, 31.VII.2021, Mao Ye leg.” “HOLOTYPE: Paederus (Harpopaederus) Paederusyei sp. n., Yang & Peng des. 2024” [red handwritten label]; SNUC. Paratypes. China – Hubei Prov. • 6 ♂♂, 5 ♀♀; Baokang County, Cuijia’ao, 31.72°N, 111.13°E, alt. 1550 m, 31.VII.2021, Mao Ye leg; SNUC • 3 ♂♂: Baokang County, Longping, alt. 1100 m, 15.VII.2017, Lu Qiu leg; SNUC.

Measurements (in mm) and ratios: BL 9.43–10.02, FL 4.46–5.01, HL 1.20–1.25, HW 1.44–1.54, AnL: 2.67–2.79; PL: 1.49–1.67; PW: 1.49–1.69; EL: 1.14–1.20; EW: 1.64–1.74; AW: 1.62–1.74; AL: 1.94–1.99; HL/HW: 0.81–0.83; HW/PW: 0.91–0.97; HL/PL: 0.75–0.81; PL/PW: 0.98–1.01; EL/PL: 0.72–0.76; diameter of eye: 0.30–0.38.

Habitus as in Fig. 1E. Coloration: head and apex of abdomen black; labrum blackish brown; antennae brown, with the four basal and two apical segments yellowish brown; pronotum red; elytra black with faint bluish hue; first four abdominal segments reddish brown; legs with dark brown femora and protibiae, and with brown to light brown meso- and metatibiae and tarsi.

Head (Fig. 1E) transverse, widest across eyes; punctation coarse and sparse; interstices glossy. Eyes convex. Antennae not particularly slender, antennomere 4 approximately 3.1 times as long as broad and antennomere 10 1.7 times as long as broad. Labrum (Fig. 6A, B) with U-shaped median excision and with broad lateral projection on either side, as well as small projection on either side of median excision. Mandibles (Fig. 6A, B) each apically with bifid molar tooth, without sexual dimorphism.

Pronotum (Fig. 1E) as long as broad, moderately convex in cross section; punctation similar to that of head, but somewhat finer.

Elytra (Fig. 1E) nearly parallel-sided, wider than long; punctation coarse, well defined, and dense. Hind wings reduced. Metatarsomere I shorter than combined length of metatarsomeres II and III.

Abdomen as broad as elytra or somewhat broader than elytra; punctation dense; interstices with shallow microsculpture; posterior margin of tergite VII without palisade fringe.

Male. Posterior margin of tergite VIII (Fig. 6E) strongly convex; sternite VII unmodified; sternite VIII (Fig. 6F) with deep posterior excision, this excision approximately 0.4 times as long as sternite VIII; aedeagus as in Fig. 6G–I and nearly symmetric; ventral plate very weakly sclerotized; dorsal plate long and weakly curved in lateral view, extending beyond apices of parameres, dorsally with two rows of 4−5 denticles at some distance from hooked apex; parameres slender and weakly curved in lateral view; internal sac with single long sclerotized spine.

Female. Tergite VIII (Fig. 6C) oblong, posterior margin of strongly convex; posterior margin of sternite VIII trifurcate as in Fig. 6D.

The species was discovered in two localities situated to southwestern Baokang, western Hubei. Some specimens were sifted from leaf litter in a mixed deciduous forest with shrubs at an altitude of 1550 m (Ye pers. comm.).

The species is named for Mao Ye, who collected some of the type specimens.

The geographically closest Harpopaederus species are P.apfelsinicus Willers, 2001, P.cultellatus Assing, 2015, and P.multidenticulatus Li, Solodovnikov & Zhou, 2014. Paederusyei is distinguished from them by the stouter pronotum, particularly by the smaller aedeagus of different morphology (dorsal plate with hooked apex; shape of the internal structure), and by the oblong female tergite VIII. For illustrations of P.apfelsinicus see Willers (2001: figs 16–23), of P.cultellatus see Assing (2015: figs 55–62), and of P.multidenticulatus see Li et al. (2014: fig. 2A–H).