Holotype: ♂, CHINA, Sichuan: Xiaojin County [小金县], near Siguniang Shan [接近四姑娘山], 30.921623°N, 102.889709°E, under rock, 4258m, 14.VII.2017, Jiang Zhu leg. (SYSB). Paratype: 1♀, same data as holotype (SNUC).

This new species is very similar to Micropeplus songi Zheng, Li & Yan, 2014 from Mt. Wahui [瓦灰山], Sichuan, but it is easy to distinguish it from the latter by a combination of the following characteristics: head with microreticulate surface; elytral punctures moderate-sized, distinctly smaller but more numerous than that of M. songi; elytral interspace I with two to three rows, II with three to four rows, III with four rows, IV with one row and V with three rows; metathoracic wings fully developed; aedeagal parameres with two long setae at apex.

Male. Body small, 2.81 mm long. Length (mm) of different body parts: head (0.31), pronotum (0.55), elytra (1.05), fore body (1.91), aedeagus (0.58). Width (mm): head (0.64), pronotum (1.16), elytra (1.22). (Head width)/(pronotal width) = 0.55, (pronotal length)/(elytral length) = 0.52.

Habitus (Figure 1A) elliptical, generally convex and sublustrous. Head, disc of pronotum, elytra and abdomen blackish brown to black; basal eight antennomeres and apical half of ultimate antennomere, maxillary and labial palpi, legs, and sides of pronotum yellowish brown to brown.

Figure 1. 

Habitus of Micropeplus liweiae sp. n. (dorsal view): A holotype ♂ B paratype ♀. Scale bars: 0.5 mm.

Head (Figure 2A) transverse, widest across eyes, width/length = 2.06. Clypeus with anterior margin broadly subrounded. Vertex with a longitudinal carina along midline in basal half; area on both sides of carina weakly impressed; one fine transverse carina and two oblique carinae at middle of inner side of each eye; spaces between carinae microreticulate. Eyes distinctly prominent. Antennae have 9 antennomeres with single-segmented clubs; antennomere I more robust than other antennomeres except IX, and about equal to length of II+III combined; II narrowed apically, shorter and slightly narrower than I; III–VI longer than wide, narrower than II, III–V subequal and longer than VI; VII and VIII transverse; IX largest and oval, covered with dense pubescence.

Figure 2. 

Micropeplus liweiae sp. n., holotype ♂: A head B mesotibia C metatibia D–F aedeagus G abdominal tergite VIII H abdominal ventrite VIII. Scale bars: 0.5 mm (A); 0.1 mm (B–H). (A–D, G dorsal view E lateral view F, H ventral view).

Pronotum subtrapezoidal, widest just before hind angles, width/length = 2.11. Sides almost obliquely linear, gradually narrowing from posterior to anterior, with ca. 4 small teeth; anterior margin broadly and distinctly emarginate and slightly arched in middle; posterior margin bisinuate; anterior angles distinctly projected forwards; posterior angles nearly rectangular; surface finely granulate; lateral areas broadly explanate; median area elevated dorsally, with fourteen cells enclosed by costae (including two small ones after anterior margin).

Scutellum shield-like with finely granulate surface.

Elytra subquadrate, width/length = 1.16, widest at about apical 2/5. Each elytron with 6 costae, one sutural, two discal, one humeral, one pseudepipleural (straight, distinctly separated anteriorly and posteriorly from epipleural costa) and one epipleural; interspaces between costae with irregular rows of moderate-sized punctures, interspace I with two to three rows, II with three to four rows, III with four rows, IV with one row and V with three rows. Metathoracic wings fully developed.

Metastemum with elongate median impression, wide and deep at base, weakening anteriorly, about half as long as metasternum. Abdomen gradually narrowed towards segment VI and abruptly narrowed from VII to apical end; tergites III–VII each strongly and transversely depressed in basal half, III with one short median longitudinal carina, IV to VI each with three longitudinal carinae almost throughout length of tergite, VII with three abbreviated carinae in about basal 1/3, VIII (Figure 2G) with apical edge almost straight; sternite VIII (Figure 2H) with apical edge distinctly and subroundly emarginated, and semilunarly depressed before emargination.

Protibia without tooth on medial margin; meso- (Figure 2B) and metatibiae (Figure 2C) each armed with a large subtriangular tooth at about apical 1/3 of medial margins.

Aedeagus (Figure 2D–F) stout; median lobe weakly bent ventrad in apical part; parameres fused with median lobe, each with two long setae at apex.

Female. Similar to male in general appearance (Figure 1B), including anterior margin of clypeus which lacking sexual dimorphism, but distinct in the following characters: meso- and metatibiae without tooth on medial margins, and sternite VIII without emargination at apical edge.

Specimens were found under a rock in an alpine meadow (Figure 3), with high altitude over 4000 m.

Figure 3. 

Habitat of Micropeplus liweiae sp. n. The new species was collected under a rock (red arrow) in an alpine meadow of Xiaojin, Sichuan.

China (Sichuan).

The specific epithet is dedicated to Ms. Li-Wei Liu, the mother of Jiang-Zhu (the collector and corresponding author), for her care and constant support to him.