Holotype. China – Chongqing • ♂; glued on a card with two labels as follows: “China: Chongqing City, Chengkou County, Gaoxing Xiang, West Daba Shan, Gou-Di-Tang; 32°08'N, 108°37'E; alt. 1830 m; 24.IV.2008; Huang & Xu leg.” “HOLOTYPE: Sinlathrobium assingi sp. nov., Chen & Peng des. 2024” [red handwritten label]; SNUC. Paratypes. China – Chongqing • 1♀; Chengkou County, Gaoxing Xiang, West Daba Shan, Gou-Di-Tang, 32°08'N, 108°37'E, alt. 1830 m, 24.IV.2008, Huang & Xu leg; SNUC.

Measurements (in mm) and ratios: BL 7.67–7.73, FL 3.61–3.67, HL 0.85–0.92, HW 1.02–1.04, PL 1.05–1.11, PW 0.96–0.98, EL 1.04–1.05, AL 1.94–2.04, AeL 1.02, HL/HW 0.83–0.88, HW/PW 1.06, HL/PL 0.81–0.83, PL/PW 1.09–1.13, EL/PL 0.95–0.99.

Habitus as in Fig. 1A. Coloration: body black, elytra with moderately large, transverse yellowish spot posteriorly reaching lateral and posterior margins; legs yellowish with darker femora; antennae dark brown to brown.

Figure 1. 

Habitus (A–C): A Sinlathrobium assingi sp. nov. B Sinlathrobium chenzhilini sp. nov. C Sinlathrobium lobrathioides. Forebody (D–F): D Sinlathrobium assingi sp. nov. E Sinlathrobium chenzhilini sp. nov. F Sinlathrobium lobrathioides. Scale bars: 1.0 mm.

Head (Fig. 1D) transverse, widest across eyes; punctation coarse and very dense, in median dorsal portion and on frons somewhat sparser; interstices with shallow microsculpture. Eyes large and bulging, 0.80–0.83 times as long as postocular region in dorsal view. Antennae not particularly slender.

Pronotum (Fig. 1D) nearly parallel-sided; punctation sparser and distinctly coarser than that of head; interstices without microsculpture and glossy.

Elytra (Fig. 1D) broader than pronotum; humeral angles weakly pronounced; punctation coarse and rather dense; interstices without microsculpture and glossy. Hind wings presumably fully developed.

Abdomen somewhat narrower than elytra; punctation conspicuously dense and fine on all tergites; interstices with distinct microsculpture and subdued gloss; posterior margin of tergite VII with palisade fringe.

Male. Sternites III–VI unmodified; sternite VII (Fig. 2D) strongly transverse, with shallow median impression without modified pubescence, posterior margin broadly and shallowly concave; sternite VIII (Fig. 2E) weakly transverse, with shallow median impression posteriorly, this impression without modified setae, posterior excision V-shaped and moderately deep; aedeagus as in Fig. 2F, G, ventral process somewhat asymmetric, dorsal plate lamellate and weakly sclerotized.

Figure 2. 

Sinlathrobium assingi sp. nov. A female tergite VIII B female sternite VIII C female tergites IX–X D male sternite VII E male sternite VIII F aedeagus in lateral view G aedeagus in ventral view. Scale bars: 0.2 mm.

Female. Tergite VIII (Fig. 2A) with strongly convex posterior margin; sternite VIII (Fig. 2B) weakly oblong, and with strongly convex posterior margin; tergite IX (Fig. 2C) with slender posterior processes; tergite X flat, nearly reaching anterior margin of tergite IX.

The type locality is situated to the west of Chengkou, northern Chongqing. The specimens were sifted from leaf litter, moss, and grass roots in shrub habitats at an altitude of 1830 m.

This species is dedicated to our friend, Volker Assing, who prematurely passed away. He was a renowned specialist on mainly Palaearctic Staphylinidae.

The highly similar male sexual characters, particularly the shape of the male sternites VII–VIII and the similarly derived morphology of the aedeagus, suggest that S. assingi is very closely related to S. chenzhilini sp. nov. and S. lobrathioides (Assing, 2012). It differs from S. chenzhilini and S. lobrathioides by the yellowish legs, particularly by the distinctly denser and coarser punctation of the pronotum, by the somewhat asymmetric ventral process of the aedeagus, and by the differently shaped female tergites IX–X. For illustrations of S. chenzhilini see Figs 1B, 1E, 3 and for S. lobrathioides see Figs 1C, 1F, 4A–C and Assing (2012: figs 315–320).

Figure 3. 

Sinlathrobium chenzhilini sp. nov. A female tergite VIII B female sternite VIII C female tergites IX–X D male sternite VII E male sternite VIII F aedeagus in lateral view G aedeagus in ventral view. Scale bars: 0.2 mm.

Holotype. China – Guangxi Prov. • ♂; glued on a card with two labels as follows: “China: Guangxi Prov., Xing’an County, Maoer Shan, 25°52'27''N, 110°24'44''E, alt. 1940 m, 29.VII.2014, Peng, Song, Yu & Yan leg.” “HOLOTYPE: Sinlathrobium chenzhilini sp. nov., Chen & Peng des. 2024” [red handwritten label]; SNUC. Paratypes. China – Guangxi Prov. • 7♂♂, 5♀♀; Xing’an County, Maoer Shan, 25°52'27''N, 110°24'44''E, alt. 1940 m, 29.VII.2014, Peng, Song, Yu & Yan leg; SNUC • 2♂♂; Xing’an County, Maoer Shan, 25°53'15''N, 110°25'47''E, alt. 2030 m, 30.VII.2014, Peng, Song, Yu & Yan leg; SNUC.

Measurements (in mm) and ratios: BL 6.12–7.78, FL 3.67–3.89, HL 0.89–0.94, HW 1.04–1.09, PL 1.11–1.20, PW 0.96–1.05, EL 1.07–1.15, AL 1.81–1.91, AeL 1.04–1.14, HL/HW 0.85–0.87, HW/PW 1.03–1.08, HL/PL 0.78–0.80, PL/PW 1.14–1.16, EL/PL 0.95–0.96.

Habitus as in Fig. 1B. Coloration: body black, elytra with extensive orange spot in postero-lateral angles, this spot reaching posterior and lateral margins, near suture; legs with the femora blackish, tibiae dark brown and tarsi brown; antennae dark brown to brown.

Head (Fig. 1E) transverse, widest across eyes; punctation coarse and very dense, in median dorsal portion and on frons distinctly sparser; interstices with shallow microsculpture. Eyes large and bulging, 0.90–0.92 times as long as postocular region in dorsal view. Antennae not particularly slender.

Pronotum (Fig. 1E) nearly parallel-sided; punctation distinctly sparser and distinctly coarser than that of head; interstices without microsculpture and glossy.

Elytra (Fig. 1E) broader than pronotum; humeral angles pronounced; punctation coarse and rather dense; interstices without microsculpture and glossy. Hind wings fully developed.

Abdomen somewhat narrower than elytra; tergites III–VI with very fine and dense punctation, tergites VII–VIII with distinctly sparser punctation; posterior margin of tergite VII with palisade fringe.

Male. Sternites III–VI unmodified; sternite VII (Fig. 3D) strongly transverse, with shallow median impression without modified pubescence, posterior margin broadly concave; sternite VIII (Fig. 3E) transverse, with shallow median impression posteriorly, this impression without modified setae, posterior excision V-shaped and moderately deep; aedeagus as in Fig. 3F, G, ventral process symmetric, dorsal plate long and strongly sclerotized.

Female. Tergite VIII (Fig. 3A) with broadly convex posterior margin; sternite VIII (Fig. 3B) weakly oblong, and with strongly convex posterior margin; anterior portion of tergite IX (Fig. 3C) divided in middle, tergite X (Fig. 3C) approximately twice as long as tergite IX in the middle.

The type locality is situated in the Maoer Shan to the north of Guilin, northern Guangxi. The specimens were sifted from leaf litter and dead wood in mixed deciduous forests at altitudes from approximately 1940 up to 2030 m.

This species is dedicated to Zhi-Lin Chen, who supported us on our field trips.

The highly similar male sexual characters, particularly the shape of the male sternites VII–VIII and the similarly derived morphology of the aedeagus, suggest that S. chenzhilini is very closely related to S. assingi sp. nov. and S. lobrathioides (Assing, 2012). It differs from S. assingi by the coloration of legs, particularly by the distinctly sparser and finer punctation of the pronotum, and by the differently shaped ventral process of the aedeagus. It differs from S. lobrathioides by the somewhat longer elytra, particularly by the sparser punctation of the head and pronotum, and by the longer dorsal plate of the aedeagus. For illustrations of S. assingi see Figs 1A, 1D, 2.

China – Chongqing • 3♂♂, 3♀♀; Jinfo Shan, 29°01'25''N, 107°11'01''E, alt. 2160 m, 09.VII.2015, Jiang, Peng, Tu & Zhou leg; SNUC.

The original description is based on a single male. The previously unknown female sexual characters are as follows: tergite VIII (Fig. 4A) with strongly convex posterior margin; sternite VIII (Fig. 4B) oblong, and with strongly convex posterior margin; anterior portion of tergite IX (Fig. 4C) divided in middle, tergite X (Fig. 4C) nearly reaching anterior margin of tergite IX. For illustrations of the male sexual characters see Assing (2012: figs 315–320). The specimens were sifted from dead wood in mixed deciduous forests at an altitude of about 2160 m (Fig. 4D, E).

Figure 4. 

Sinlathrobium lobrathioides. A female tergite VIII B female sternite VIII C female tergites IX–X D S. lobrathioides walking on the dead wood E habitat (Jinfo Shan). Scale bars: 0.2 mm.