Discoxenus shenzhenensis Xu, Cai, Zeng

Xu, Wang, Cai, Yu-Jie, Zeng, Qing-Huai, Wang, Wei-Min, Yu, Xin-Fan & Song, Xiao-Bin, 2022, Discoxenus Wasmann new to China with description of a new species (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 5175 (3), pp. 389-393 : 390-391

Discoxenus shenzhenensis Xu, Cai, Zeng & Song sp. nov.

(Chinese name: 深圳DZDKOiffl)

Figs. 1 , 3–16

Type material. Holotype. China: male on slide, glued on a card with labels as follows: “ China: Guangdong, Shenzhen, Wutong Mt. , 22°34′48″N, 114°12′36″E; alt. 500 m, 21.IX.2021, Yujie Cai & Chenglin Zhou leg.” “ Holotype / Discoxenus shenzhenensis / Xu, Cai, Zeng & Song” [red handwritten label] ( SHNU) . Paratypes. 1 male, same data as holotype ( SHNU) . 1 male, Guangdong Prov., Guangzhou, Tianhe Dist., Guangdong Forestry Vocational and Technical School , Longdong ; 23°11′29″N, 113°22′39″E; alt. 30–100 m, 1.VII.2012, Huang S-B leg. ( SHNU) . 1?, China: Guangdong, Zhongshan City, Wuguishan (I桂山), 22°25′56.79″N, 113°26′40.46″E, 21.X.–18.XI.2020, by FIT ( SHNU) .

Diagnosis. The genus is currently subdivided into two species groups: the Discoxenus assmuthi group and the D. latiabdominalis group ( Kanao & Maruyama 2015). According to the tergite X with posterior half covered with a batch of setae, the small basal capsule and strongly developed distal crest of aedeagal median lobe, Discoxenus shenzhenensis sp. nov. belongs to the D. assmuthi species group, it can be easily distinguished from all congeners by a combination of the following two character states: macrochaetotaxy of tergites III–VIII (6, 6, 6, 6, 6, 6); elytra and abodmen sparesly covered with relatively long yellow setae. The new species is closely allied to D. katayamai Kanao & Maruyama, 2010 from Thailand and Cambodia in general habitus, but can be readily separated from it by antennal segment XI approximately 2.1 times longer than wide (in D. katayamai , antennal segment XI thick, length approximately 1.4 times as long as wide); the longer incisor tooth of both mandibles; the molar tooth of right mandible very small; the slenderer apical lobe of aedeagal median lobe and the longer apical lobe of paramere.

The key to the Southeast Asian species of Discoxenus ( Kanao & Maruyama 2015) should be modified at the couplet #2 as follows to accommodate the new species:

2. Elytra sparsely covered with relatively long setae.......................................................... 2a

- Elytra covered with no or few short setae except for anterolateral outer corner..................................... 3

2a. Antennal segment XI approximately 1.4 times longer than wide; the molar tooth of right mandible distinct.... D. katayamai

- Antennal segment IX approximately 2.1 times longer than wide; the molar tooth of right mandible very small............................................................................................. D. shenzhenensis sp. n.

Description.

Body ( Figs 1 , 18 ) smooth, glabrous. Coloration: Light reddish-yellow overall.

Head ( Fig. 4 ) approximately 1.5 times wider than long. Antenna ( Fig. 3 ) with segment II with 3 macrosetae; segment XI approximately 2.1 times longer than wide, widest around middle. Labrum ( Fig. 5 ) with anterior margin slightly concave at middle; median projection of apodeme short, with apex rounded; 5–6 lateral setae present in ventral view. Mandibles ( Figs. 7–8 ), covered with 38–42 pores. Left mandible ( Fig. 7 ) with adoral margin moderately pointed around middle. Right mandible ( Fig. 8 ) with molar tooth almost reduced. Maxillary palpal segment III approximately 2.1 times longer than wide. Mentum ( Fig. 6 ) approximately 2.4 times wider than long, covered with around 58 pores. Labium with prementum covered with approximately 8 pores.

Pronotum ( Fig. 12 ) covered with approximately 68 macrosetae. Elytron ( Fig. 13 ) transverse, sparsely covered with yellow setae, 16 macrosetae present on disc. Metaventrite approximately 1.8 times longer than mesoventrite.

Tergites ( Fig. 1 ) and sternites sparsely covered with yellow setae. Macrochaetotaxy of abdominal tergites III– VIII = 6, 6, 6, 6, 6, 6. Sternite III with posterior half densely covered with setae. Sternites IV–VII with posterior half sparsely covered with setae. Sternites III–VII with 4–8 macrosetae at posterior margin.

Male. Tergite VIII ( Fig. 9 ) with posterior margin rounded, 3 pairs of macrosetae present at posterior margin, with 2 pairs of macrosetae around middle. Sternite VIII ( Fig. 10 ) with posterior margin slightly rounded, 3 pairs of macrosetae present at posterior margin, with 2 pairs of macrosetae at middle. Median lobe of aedeagus narrowed apically in ventral view ( Fig. 14 ); basal capsule with distal crest large in lateral view ( Fig. 15 ); apical lobe less than half as wide as basal capsule in lateral view ( Fig. 15 ). Paramere ( Fig. 16 ) with paramerite approximately 3 times wider than condylite; velar sac sclerite with 6–9 setae; apical lobe with 3 minute setae at apex.

Female. Unknown.

Measurements. BL: 1.67–1.92 mm; FBL: 0.86–0.89 mm; PL: 0.61–0.65 mm; PW: 0.91–0.97 mm; EL: 0.24– 0.25 mm; EW: 0.94–1.01 mm; PL/PW: 0.67; EL/EW: 0.24–0.27.

Distribution. China (Guangdong).

Symbiotic host. Odontotermes sp. ( Fig. 2 )

Etymology. The species is named after its type locality, Shenzhen.

Figures

FIGURES 1–2. Habitus—1. Discoxenus shenzhenensis, 2. Odontotermes sp. Scales = 1 mm.

FIGURES 3–16. D. shenzhenensis—3. Antenna, 4. Head, 5. Labrum, 6. Mentum, 7. Mandible, left, 8. Mandible, right, 9. Tergite VIII, 10. Sternite VIII, male, 11. Tergites IX and X, 12. Pronotum, 13. Elytron, 14. Median lobe of aedeagus, ventral view, 15. Median lobe of aedeagus, lateral view, 16. Paramere. Scales = 0.1 mm.

FIGURES 17–18. Habits and habitats 17. log with Odontotermes termites, 18. Attack behavior of termites (Photo by Mr.Yu-Jie Cai from Guangdong, Shenzhen, Wutong Mt. at 21 Sep 2021).