Holotype: ♂, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Hamashi, 24°55'37"N, 112°59'21"E, 1,750 m, 01.V.2015, Peng, Tu & Zhou leg.’ (SNUC). Paratypes: 3 ♀♀, same data as the holotype (SNUC); 2 ♀♀, labeled ‘China: Guangdong Prov., Ruyuan County, Guangdong Di Yi Feng, 24°55'29.62"N, 112°59'31.42"E, 1,538–1,784 m, 28.VI.2020, Xia, Zhang, Yin & Lin leg.’ (SNUC); 2 ♀♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Shikengkong, 24°55'33"N, 112°59'29"E, 1,820 m, 30.IV.2015, Peng, Tu & Zhou leg.’ (SNUC); 1 ♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Shikengkong, 24°55'38"N, 112°59'30"E, 1,850 m, 27.IV.2015, Peng, Tu & Zhou leg.’ (SNUC); 1 ♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Laopengyidui, 24°56'21"N, 113°01'21"E, 1,260 m, 02.V.2015, Peng, Tu & Zhou leg.’ (SNUC); 1 ♂, 1 ♀, labeled ‘China: Guangdong Prov., Shixing County, Chebaling, 24°43'12.27"N, 114°11'18.03"E, 904–1,004 m, 23.VI.2020, Xia, Zhang, Yin & Lin leg.’ (SNUC).

Measurements (in mm) and ratios: BL 5.34–6.67, FL 2.19–2.67, HL 0.76–0.98, HW 0.78–0.87, AnL 1.49–1.74, PL 1.00–1.09, PW 0.82–0.93, EL 0.41–0.65, AL 0.81–0.83, HL/HW 0.97–1.13, HW/PW 0.90–1.00, HL/PL 0.75–0.92, PL/PW 1.15–1.27, EL/PL 0.41–0.60.

Habitus as in Figure 1A. Body brown, legs, and antennae light brown.

Figure 1. 

Male habitus of Lathrobium spp. A L. yangyihani B L. jiaxingyangi C L. wangxingmini. Scale bars: 1.0 mm.

Head approximately as long as broad; punctation moderately coarse and sparse, sparser in median dorsal portion; interstices with shallow microreticulation; eyes small and composed of approximately 40 ommatidia.

Pronotum nearly parallel-sided; punctation somewhat sparser than that of head; impunctate midline broad; interstices without microsculpture.

Elytral punctation moderately dense, shallow, and ill-defined. Hind wings completely reduced.

Abdomen with fine and moderately sparse punctation, that of tergite VII somewhat sparser than that of anterior tergites; interstices with shallow microsculpture; posterior margin of tergite VII without palisade fringe.

Male. Sternites III–VI unmodified; sternite VII (Fig. 2D) with very shallow postero-median impression without distinctly modified setae, posterior margin weakly concave in the middle; sternite VIII (Fig. 2E) with symmetric, subtriangular emargination and shallow impression; aedeagus as in Figure 2F and G, with stout ventral process of highly distinctive shape; dorsal plate with moderately long apical portion and very short basal portion; internal sac without sclerotized spines.

Figure 2. 

Lathrobium yangyihani. A female tergite VIII B female sternite VIII C female tergites IX–X. D male sternite VII E male sternite VIII F aedeagus in ventral view G aedeagus in lateral view. Scale bars: 0.5 mm.

Female. Posterior margin of tergite VIII (Fig. 2A) strongly convex. Posterior margin of sternite VIII (Fig. 2B) strongly convex and with moderately dense micropubescence; tergite IX (Fig. 2C) with very short, medially undivided antero-median portion and moderately long postero-lateral processes; tergite X (Fig. 2C) 2.5 times as long as antero-median portion of tergite IX.

The new species resembles L. guangdongense Peng & Li, 2014 in habitus and the similarly derived morphology of Sternites VII–VIII but differs from this species by the stouter ventral process and the simple internal sac of the aedeagus. For illustrations of L. guangdongense, see Figure 3A–C and Peng et al. (2014).

Figure 3. 

Lathrobium guangdongense (A–C) and L. jiaxingyangi (D–G) A female tergite VIII B female sternite VIII C female tergites IX–X. D male sternite VII E male sternite VIII F aedeagus in ventral view G aedeagus in lateral view. Scale bars: 0.5 mm.

The species is named after Yi-Han Yang, who supported us on our field trips.

The species was found in six adjacent localities in western Ruyuan County to southeastern Shixing County. A specimen was sifted, together with L. guangdongense, from moist leaf litter of a secondary mixed and deciduous forest at an altitude of 1,260 m (Fig. 5).

3 ♂♂, 6 ♀♀, China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Laopengyidui, 24°56'21"N, 113°01'21"E, 1,260 m, 02.V.2015, Peng, Tu & Zhou leg. (SNUC); 4 ♂♂, 3 ♀♀, China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Laopengkeng, 24°56'29"N, 113°00'27"E, 1,360 m, 29.V.2015, Peng, Tu & Zhou leg. (SNUC); 1 ♀, China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Walkway, 24°55'57"N, 113°00'18"E, 1,220 m, 28.IV.2015, Peng, Tu & Zhou leg. (SNUC); 2 ♂♂, China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Disilindao, 24°55'47"N, 112°59'50"E, 1,500 m, 05.V.2015, Peng, Tu & Zhou leg. (SNUC); 1 ♂, China: Hunan Prov., Yizhang County, Mangshan Nature reserve, 24°56'26"N, 112°59'18"E, 1400 m, 26.IV.2015, Peng, Tu & Zhou leg. (SNUC); 3 ♂♂, 4 ♀♀, China: Guangdong Prov., Ruyuan County, Nanling National Nature reserve, 24°55'43.67"N, 113°00'58.50"E, 1,020 m, sifted, 27.VI.2020, Lin, Xia, Yin & Zhang leg. (SNUC); 1 ♂, 2 ♀♀, China: Hunan Prov., Xinning County, Shunhuang Shan Nature Reserve, 26°22'33.82"N, 110°59'32.11"E, 1,112 m, sifted, 24.VIII.2020, leaf litter, sifted, Chong Li leg. (SNUC); 2 ♂♂, 1 ♀, China: Guangdong Prov., Ruyuan County, Nanling Nature reserve, 24°55'42.9"N, 113°00'59.05"E, 1,020–1,250 m, 04.V.2021, Hu, Lin, Zhou & Li leg. (SNUC); 2 ♀♀, China: Guangdong Prov., Ruyuan County, Nanling Nature reserve, 24°56'16.20"N, 113°00'8.43"E, 980–1,350 m, 01.V.2021, Hu, Lin, Zhou & Li leg. (SNUC); 2 ♂♂, 2 ♀♀, China: Guangdong Prov., Ruyuan County, Nanling Nature reserve, Xiaohuangshan, 24°53'44.7"N, 113°01'26.9"E, 1,270–1,570 m, 02.V.2021, Hu, Lin, Zhou & Li leg. (SNUC).

The original description is based on four males. The previously unknown female sexual characters are as follows: posterior margin of tergite VIII (Fig. 2A) convex; posterior margin of sternite VIII (Fig. 2B) strongly convex and with moderately dense micropubescence; tergite IX (Fig. 2C) with median suture and long postero-lateral processes; tergite X (Fig. 2C) nearly reaching anterior margin of tergite IX. The above records from Hunan represent new province records. For illustrations of the habitus and the male sexual characters, see Peng et al. (2014).

Holotype: ♂, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Shikengkong, 24°55'33"N, 112°59'29"E, 1,820 m, 30.IV.2015, Peng, Tu & Zhou leg.’ (SNUC). Paratypes: 1 ♂, same data, but ‘24°55'38"N, 112°59'30"E, 1,850 m, 27.IV.2015, Peng, Tu & Zhou leg’ (SNUC).

Measurements (in mm) and ratios: BL 7.95–8.34, FL 3.12–3.24, HL 1.09–1.14, HW 1.09, AnL 1.99–2.16, PL 1.34–1.37, PW 1.09–1.14, EL 0.68–0.73, AL 1.55, HL/HW 1.00–1.04, HW/PW 0.96–1.00, HL/PL 0.82–0.83, PL/PW 1.20–1.22, EL/PL 0.51–0.53.

Habitus as in Figure 1B. Body dark reddish brown, legs reddish brown, antennae dark to light reddish brown.

Head punctation moderately fine and moderately dense, not sparser in median dorsal portion; interstices with shallow microsculpture. Eyes moderately small and composed of approximately 60 ommatidia.

Pronotum nearly parallel-sided; punctation somewhat sparser than that of head; impunctate midline broad; interstices without microsculpture.

Elytral punctation moderately dense and shallow. Hind wings completely reduced.

Abdomen with fine and moderately dense punctation, that of tergite VII somewhat sparser than that of anterior tergites; interstices with shallow, but distinct microsculpture; posterior margin of tergite VII without palisade fringe.

Male. Sternites III–VI unmodified; sternite VII (Fig. 3D) strongly transverse and symmetric, with shallow median impression with modified short black setae, posterior margin broadly and very weakly concave; sternite VIII (Fig. 3E) approximately as long as broad, with moderately extensive median impression posteriorly, this impression with numerous distinctly modified, stout black setae, posterior excision relatively deep; aedeagus as in Figure 3F and G; ventral process weakly hooked apically in lateral view; dorsal plate with long apical portion and very short basal portion; internal sac with one sclerotized spine.

Female. Unknown.

Lathrobium jiaxingyangi resembles L. wangxingmini sp. nov. in having the similarly derived chaetotaxy of the asymmetric male sternite VIII and the long dorsal plate of the aedeagus. It is distinguished from L. wangxingmini by the lighter coloration, the smaller body size, the chaetotaxy of the male sternite VII, the shallower posterior excision of the male sternite VIII, and the morphology of the aedeagus (shape of ventral process; internal sac with one shorter sclerotized spine).

The species is named after Xing-Yang Jia, who supported us on our field trips.

The type locality is situated in the Nanling National Nature Reserve to western Ruyuan County, eastern Guangdong. The specimens were sifted from leaf litter and grass roots in shrub habitats at an altitude of 1,850 m (Fig. 6).

Holotype: ♂, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Walkway, 24°55'57"N, 113°00'18"E, 1,220 m, 28.IV.2015, Peng, Tu & Zhou leg.’ (SNUC). Paratypes: 1 ♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Shikengkong, 24°55'33"N, 112°59'29"E, 1,820 m, 30.IV.2015, Peng, Tu & Zhou leg.’ (SNUC); 1 ♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, Shikengkong, 24°55'38"N, 112°59'30"E, 1,850 m, 27.IV.2015, Peng, Tu & Zhou leg’ (SNUC); 1 ♀, labeled ‘China: Hunan Prov., Yizhang County, Mangshan Nature reserve, 24°56'26"N, 112°59'18"E, 1,400 m, 26.IV.2015, Peng, Tu & Zhou leg.’ (SNUC); 1 ♂, 2 ♀♀, labeled ‘China: Guangdong Prov., Ruyuan County, Nanling National Nature Reserve, 1,090 m, 18.VI.2007, Huang & Xu leg.’ (SNUC).

Measurements (in mm) and ratios: BL 8.62–10.56, FL 3.48–4.27, HL 1.30–1.67, HW 1.30–1.52, AnL 2.32–2.70, PL 1.57–1.85, PW 1.33–1.57, EL 0.61–0.83, AL 2.25, HL/HW 1.00–1.15, HW/PW 0.96–0.98, HL/PL 0.82–0.95, PL/PW 1.18–1.19, EL/PL 0.39–0.45.

Habitus as in Fig. 4C. Body blackish brown, legs brown, antennae dark to light brown.

Figure 4. 

Lathrobium wangxingmini. A female tergite VIII B female sternite VIII C female tergites IX–X. D male sternite VII E male sternite VIII F aedeagus in ventral view G aedeagus in lateral view. Scale bars: 0.5 mm.

Head transverse; punctation coarse and dense, sparser in median dorsal portion; interstices with distinct microsculpture.

Pronotum nearly parallel-sided; punctation somewhat sparser than that of head; impunctate midline broad; interstices without microsculpture. Eyes moderately big and composed of approximately 80 ommatidia.

Elytral punctation dense and defined. Hind wings completely reduced. Protarsi without appreciable sexual dimorphism, distinctly dilated.

Abdomen with fine and dense punctation, punctation of tergite VII slightly less dense than that of anterior tergites; interstices with shallow microsculpture; posterior margin of tergite VII without palisade fringe.

Male. Sternites III–VI unmodified; sternite VII (Fig. 4D) strongly transverse, with shallow median impression posteriorly with numerous distinctly modified, short black setae, posterior margin nearly truncate; sternite VIII (Fig. 4E) strongly modified and of distinctive shape and chaetotaxy, with deep and extensive median impression, middle of this impression with unmodified pubescence, laterally with dense short and very stout black setae, posterior margin deep and weakly asymmetric; aedeagus as in Figure 4F and G; ventral process asymmetric and apically acute; dorsal plate with long apical portion and very short basal portion; internal sac with one long sclerotized spine.

Female. Posterior margin of tergite VIII (Fig. 4A) strongly convex. Posterior margin of sternite VIII (Fig. 4B) strongly convex and with moderately dense micropubescence; tergite IX (Fig. 4C) with short antero-median portion and slender postero-lateral processes; tergite X (Fig. 4C) 2.5 times as long as antero-median portion of tergite IX.

Lathrobium wangxingmini resembles L. jiaxingyangi sp. nov. in having the similarly derived chaetotaxy of the asymmetric male sternite VIII and the long dorsal plate of the aedeagus. It is distinguished from L. jiaxingyangi by the darker coloration, the larger body size, more dense short black setae in the impression of the male sternite VII, the deeper posterior excision of the male sternite VIII and the morphology of the aedeagus (shape of ventral process; internal sac with one longer sclerotized spine).

The species is dedicated to Xing-Min Wang, who supported us on our field trips.

The species was found in five adjacent localities in western Ruyuan County to southern Yizhang County. Some specimens were sifted from the leaf litter of mixed deciduous forests at an altitude of 1,090 m (Fig. 7).

Figures 5–7. 

Collecting sites on the Nanling National Nature Reserve 5 type localities of Lathrobium yangyihani (1,260 m) 6 type locality of Lathrobium jiaxingyangi (1,850 m) 7 type locality of Lathrobium wangxingmini (1,090 m).