Stenus cirrus, L. Benick, 1940

Tang, Liang, Liu, Sheng-Nan & Dong, Xin-Yu, 2018, Seven new species of the Stenus cirrus group (Coleoptera, Staphylinidae) from Sichuan, Southwest China, Zootaxa 4425 (3), pp. 527-540 : 539

Key to species of the Stenus cirrus group of Sichuan

1 Hind legs with tarsomeres IV simple...................................................................... 2

- Hind legs with tarsomeres IV distinctly bilobed.............................................................. 3

2 Abdominal tergites without reticulation. BL= 2.6–2.8 mm, FB= 1.3 mm. Aedeagus: Fig. 5 in Puthz, 2012................................................................................................. S. beckeri L. Benick, 1941

- Last abdominal tergites reticulated. BL= 2.3–2.8 mm, FB= 1.2–1.3 mm. Aedeagus: Fig. 6 in Puthz, 2012............................................................................................... S. erlangmontium Puthz, 2012

3 Abdominal segments III and IV with paratergites............................................................ 4

- Abdominal segments III and IV without paratergites.......................................................... 5

4 Abdominal segments V and VI with paratergites. BL: 4.1–4.3 mm, FL: 2.0 mm. Habitus: Fig. 3; sexual characters: Figs. 22–27........................................................................................ S . lineatus sp. n.

- Abdominal segments V and VI without paratergites. BL: 4.2–4.6 mm, FL: 1.9–2.3 mm. Habitus: Fig. 7; sexual characters: Figs. 44–49.......................................................................... S . brevilineatus sp. n.

5 Elytra stout with EL/EW=0.75–0.76; pronotum bicolor with lateral portions distinctly lighter. BL: 4.1–4.5 mm, FL: 1.8–1.9 mm. Habitus: Fig. 6; sexual characters: Figs. 40–43.......................................... S . xichangensis sp. n.

- Elytra slender with EL/EW≥0.85; pronotum unicolor......................................................... 6

6 Head distinctly narrower than elytra, macropterous. BL= 3.3–4.5 mm, FL: 1.9–2.1 mm. Aedeagus: Fig. 4 in Puthz, 1998.................................................................................... S. aeneonitens Puthz, 1998

- Head distinctly wider than elytra, brachypterous............................................................. 7

7 Smaller species, BL= 3.2–3.3 mm, FL= 1.5 mm; head black and rest parts reddish brown. Habitus: Fig. 5; sexual characters: Figs. 34–39......................................................................... S . jiudingshanus sp. n.

- Larger species, BL≥ 3.7mm, FL≥ 1.8 mm; body with different coloration.......................................... 8

8 Elytra with distinct spots, disk relatively even, punctation distinctly wider than apical cross section of antennal segment II. BL: 3.7–4.9 mm, FL: 1.8–2.1 mm. Habitus: Fig. 4; sexual characters: Figs. 28–33....................... S . emeishanus sp. n.

- Elytra with indistinct spots or without spots, disk uneven, punctation as wide as apical cross section of antennal segment II....................................................................................................... 9

9 Larger species; elytra broader than long. BL: 4.6–5.2 mm, FL: 2.0– 2.3 mm. Habitus: Fig. 1; sexual characters: Figs. 8–15....................................................................................... S . cariniventris sp. n.

- Smaller species; elytra at least as long as wide. BL: 4.0– 4.1 mm, FL: 1.9–2.0 mm. Fig. 2; sexual characters: Figs. 16–21........................................................................................... S . jiangrixini sp. n.

Figures

FIGURES 22–27. Stenus lineatus. 22 male sternite VIII 23 male sternite IX 24, 25 aedeagus 26 female sternite VIII 27 valvifers and spermatheca. Scale bars: 0.25 mm.

FIGURES 44–49. Stenus brevilineatus. 44 male sternite VIII 45 male sternite IX 46, 47 aedeagus 48 female sternite VIII 49 valvifers and spermatheca. Scale bars: 0.25 mm.

FIGURES 40–43. Stenus xichangensis. 40 male sternite VIII 41 male sternite IX 42, 43 aedeagus. Scale bars: 0.25 mm.

FIGURES 34–39. Stenus jiudingshanus. 34 male sternite VIII 35 male sternite IX 36, 37 aedeagus 38 female sternite VIII 39 valvifers and spermatheca. Scale bars: 0.25 mm.

FIGURES 28–33. Stenus emeishanus. 28 male sternite VIII 29 male sternite IX 30, 31 aedeagus 32 female sternite VIII 33 valvifers and spermatheca. Scale bars: 0.25 mm.

FIGURES 8–15. Stenus cariniventris. 8 male sternite VIII 9 male sternite IX 10–12 aedeagus 13 apical portion of aedeagus in lateral view 14 female sternite VIII 15 valvifers and spermatheca. Scale bars: 0.25 mm.

FIGURES 16–21. Stenus jiangrixini. 16 male sternite VIII 17 male sternite IX 18, 19 aedeagus 20 female sternite VIII 21 valvifers and spermatheca. Scale bars: 0.25 mm.