Diartiger wangzheni Yin & He, 2020

Yin, Zi-Wei & He, Li, 2020, A new species of Diartiger Sharp from Sichuan, China (Coleoptera: Staphylinidae: Pselaphinae), Revue suisse de Zoologie 127 (2), pp. 361-366 : 361-364

Diartiger wangzheni Yin & He , sp. nov.

Figs 1-3

Type material: Holotype; ♂; CHINA, ‘ China: Sichuan , Chengdu , Dujiangyan , Zipingpu Town , Ling-yan-guanyin-shan Park , 31°1′48.48′′N, 103°36′47.12′′E, 1190 m, 2.V.2020, Z. Wang, L. He & C. Zhou leg., under rock with Lasius ants, 四川NJøø江wẍ坪DZDz灵岩Kĸ 山Ḍ区 ’ ( SNUC).

Type locality: Ling-yan-guan-yin-shan Park, Zipingpu Town, Dujiangyan, Chengdu, Sichuan, China.

Diagnosis: Male body length 2.2 mm. Anterior margin of clypeus roundly angulate at middle. Antennomeres 4 slightly more than 1.4 times as long as antennomeres 3. Meso- and metatrochanters with large triangular spine; mesofemora angulate at middle of ventral margin. Aedeagus with small ‘apical part’. Female unknown.

Description: Male. Body ( Fig. 1A ) length 2.2 mm; reddish brown. Head ( Fig. 1B ) longer than wide, length from anterior margin of clypeus to head base (excluding occipital constriction) 0.43 mm, width across eyes 0.29 mm; anterior margin of clypeus angulate, pointed at middle; each eye composed of about 20 facets; antennomeres 3 and 4 each much longer than antennomeres 1 and 2 ( Fig. 2A ); length of antennomeres 2-4 0.05, 0.23, 0.33 mm, respectively; antennomeres 4 slightly more than 1.4 times as long as antennomeres 3, broadening from base toward apex, apically truncate. Pronotum ( Fig. 1B ) subglobose, about as long as wide, length along midline 0.44 mm, maximum width 0.42 mm. Elytra ( Fig. 1A ) much wider than long, length along suture 0.58 mm, maximum width 0.84 mm; disc lacking linear microsculpture; with sub-triangular tufts of setae at posterolateral margins ( Fig. 2B ). Prosternum ( Fig. 2E ) roughly sculptured medially. Mesoventrite ( Fig. 2E ) with short intercoxal ridge. Metaventrite ( Fig. 2E ) convex, densely setose medially, lateral areas with distinct linear microsculpture. Mesotrochanters ( Fig. 2C ) with large triangular ventral spine, mesofemora ( Fig. 2C ) angulate on ventral margin at middle; metatrochanters ( Fig. 2D ) with distinct ventral spine slightly smaller than that of mesotrochanters. Abdomen large, wider than long, much wider than elytra, length along midline 0.75 mm, maximum width 0.91 mm; composite tergite broadly and deeply concave mediobasally, with tufts of curved trichomes at basolateral region ( Fig. 2B ), first pair of paratergites with curved trichome ( Fig. 2B ). Sternite 6 (VIII) with bunch of short, thick setae at middle. Aedeagus ( Fig. 2F, G ) moderately sclerotized, length 0.46 mm; median lobe at apex narrowing and strongly curved ventrad, with membranous part at dorso-apical side.

Female. Unknown.

Comparative notes: The males of the new species can be readily separated from those of all congeners by the relatively stouter habitus, the unique spination of the legs, and the configuration of the aedeagus. An identification key to males, updated from Yin & Li (2014), is provided below to aid in the discriminations of the Chinese species:

Biology: The male was found with Lasius ants ( Fig. 3C ) under a flat rock ( Fig. 3B ) in a mixed forest ( Fig. 3A ).

Distribution: China (Sichuan).

Etymology: The new species is named after Zhen Wang, one of the collectors of the holotype.

1A Dorsal surface of head and pronotum with sparse, thick, and suberect setae (Yin et al., 2010: fig. 1). Mesotrochanters lacking spine (Yin et al., 2010: fig. 4); mesofemora with large, curved projection. (Zhejiang) ........................ ............................................................................................................................. D. songxiaobini (Yin & Li, 2010)

1B Dorsal surface of head and pronotum with dense, fine setae. Mesotrochanters with spine of various forms......... 2

2A Fourth antennomeres more than twice as long as third antennomeres ................................................................... 3

2B Fourth antennomeres less than twice as long as third antennomeres .................................................................... 4

3A Mesofemora with sharp ventral spine at base ( Yin & Li, 2013: fig. 2C); mesotibiae with triangular tubercle near middle ( Yin & Li, 2013: fig. 2C); mesal margin of metatibiae distinctly protuberant at basal 1/4, then strongly curved, curved area with very dense setae ( Yin & Li, 2013: fig. 2D). (Anhui) ............ D. dentatus Yin & Li, 2013

3B Ventral margin of mesofemora regularly protuberant at base, lacking spines ( Yin & Li, 2014: fig. 2C); mesotibiae lacking tubercles near middle ( Yin & Li, 2014: Fig. 2C ); mesal margin of metatibiae moderately protuberant at basal 1/4, then moderately curved, curved area with relatively sparse setae ( Yin & Li, 2014: Fig. 2D ). (Zhejiang) ............................................................................................................................... D. zhejiangensis Yin & Li, 2014

4A Mesofemora angularly protuberant at middle ( Fig. 2C ). Sternite 6 (VIII) with bunch of short, thick setae at middle ( Fig. 1C ) (Sichuan) .............................................................................................. D. wangzheni Yin & He , sp. nov.

4B Mesofemora smooth at middle, lacking protuberances nor tubercles or spines. Sternite 6 (VIII) lacking bunch of short, thick setae at middle ..................................................................................................................................... 5

5A Anterior margin of clypeus distinctly angulate ( Yin & Li, 2013: fig. 1B) (Anhui) .................................................. .......................................................................................................................... D. yaoluopingensis Yin & Li, 2013

5B Anterior margin of clypeus approximately rounded ............................................................................................... 6

6A Mesotrochanters with large, long, and blunt ventral projection ( Nomura, 1997: fig. 6km., km-a). Median lobe of aedeagus with large ‘apical part’, area near apex lacking dense setae ( Nomura, 1997: fig. 12km.). (Yunnan) ........ ............................................................................................................................... D. kunmingensis Nomura, 1997

6B Mesotrochanters with large and sharp ventral spine ( Yin, 2018: fig. 2D). Median lobe of aedeagus with small ‘apical part’, area near apex with dense setae ( Yin, 2018: fig. 2F, G) (Beijing) .................... D. beijingensis Yin, 2018

Figures

Fig 1. Diartiger wangzheni sp. nov. male. (A) Dorsal habitus (B) Head dorsum and pronotum. (C) Tergite 5 (VIII) and sternite 6 (VIII), showing black thickened setae at middle. Scale bars: 0.5 mm in A; 0.2 mm in B-C.

Fig 2. Diartiger wangzheni sp. nov. male. (A) Right antenna (B) Elytral apex and abdominal base, showing trichomes. (C) Right middle leg (D) Right hind leg (E) Prosternum and meso- and metaventrite. (F, G) Aedeagus, in lateral (F) and ventral (G) view. Scale bars: 0.2 mm.

Fig. 3. Collection environment (A), habitat (B), and a living adult in situ (C) of Diartiger wangzheni sp. nov.