Stenus

Puthz, V., 2013, Revision der Stenus-Arten Chinas (3) (Coleoptera, Staphylinidae) 1, Linzer biologische Beiträge 45 (1), pp. 851-883 : 867-871

4. Key to the Stenus species of China (part 3)

1 Tarsal segment 4 simple...................................................................................................2

- Tarsal segment 4 bilobed..............................................................................................199

2 Abdominal segments 3-6 with distinct paratergites..........................................................3

- Abdominal segments 4-6 without paratergites, can be thread-like margined...............196

3 Base of abdominal tergites simple....................................................................................4

- Base of abdominal segments with short carinae...........................................................154

4 Larger species, FB> 1.9mm ..............................................................................................5

(key see in revision part 1: Philippia 13: 193-195, 2008)

- Smaller species, FB d 1.9mm ..........................................................................................55

(key see in revision part 2: Philippia 15: 116-119, 2012)

154 Base of abdominal tergites with 3 short carinae...........................................................155

- Base of abdominal tergites with 4 short carinae...........................................................183

155 Sternum 9 acute apicolaterally (figs 1, 2), mostly larger species..................................156

- Sternum 9 serrate apicolaterally (fig. 3), smaller species ( S. humilis -group). Some of the species of this group are variable in the elytral proportions. In some cases identification is only possible by examining the aedeagus. Note: Some species which have no distinct basal carinae of abdominal segments strongly resemble micropterous/apterous species of the S. humilis -group ( S. qionglaimontium PUTHZ, M. xuemontium PUTHZ and S. gaoershimontis PUTHZ : see "revision part 2); these species have a strongly bump-like elevated median portion of frons and in the median lobe two separate expulsion hooks instead of an expulsion clasp as the species of the S. humilis -group................................................................................................................176

156 Tergite 10 with a spot of short and shiny pubescence. Smaller species ( S. circularis - group)...........................................................................................................................157

- Tergite 10 without a spot of short and shiny pubescence ( S. clavicornis -group)..........159

157 Head narrower than elytra.: Apex of median lobe acute (fig. 5, PUTHZ 1968). 1.8- 2.5mm (FB 1.3-1.4mm). China (Sichuan, Guizhou, Zhejiang, Shanghai, Jiangsu, Shaanxi, Shanxi, Hebei), Laos, Japan..................................................... S. sexualis SHARP

- Head as broad as or broader than elytra.: Apex of median lobe with a small knob.

3.0-4.0mm (FB 1.7-1.9mm). China (Yunnan, Guangxi), Myanmar, Thailand, Laos, Vietnam, Malaysia (Selangor, Perak, Pahang, Sabah), Indonesia (Sumatra, Siberut, Java)........................................................................................ S. megacephalus CAMERON

158 Elytra each with a reddish-yellow spot. (Note: this spot may become indistinct, therefore 1 species is listed here twice)........................................................................159

- Elytra without a reddish-yellow spot............................................................................161

159 Elytral spot in about middle of elytra (fig. 4).: Metafemora simple.........................160

- Elytral spot in posterior half of elytra (fig. 5).: Inside of metafemora densely set with long setae. E (fig.18). 4.8-6.0mm. China (Sichuan, Shaanxi)..................................... ...................................................................................................... S. lanuginosipes PUTHZ

160 Head broader (HW: EW>0.88).: E (fig.10). 4.8-6.3mm (FB 2.4-2.7mm). China (Fujian, Hubei, Jiangxi, Shaanxi, Shandong, Beijing, Gansu), Japan................................. ..................................................................................................... S. calliceps BERNHAUER

- Head less broad (HW: EW <0.86).: E (fig.17). 4.5-5.5mm (FB 2.3-2.5mm). China (Yunnan), N India, Pakistan, Nepal)............................................... S. kraatzi BERNHAUER

161 Paratergites less broad, directed ventrad, paratergite 4 at most as broad as antennal segment 1......................................................................................................................162

- Paratergites broader, directed horizontally or dorsad, paratergite 4 broader than antennal segment 1.......................................................................................................165

162 Elytra very densely punctate.........................................................................................163

- Elytral sculpture strongly rugose/vorticose..................................................................164

163 Last tergites reticulate. see 160 ............................................... S. calliceps BERNHAUER

- Last tergites without reticulation.: E (fig.14). 4.0-5.0mm (FB 2.1-2.4mm) China (Sichuan, Guizhou, Hongkong, Fujian, Taiwan, Hubei, Zhejiang, Henan. Shaanxi, Shanxi, Beijing), Japan, Korea, Russia (Far East) ................................... S. distans SHARP

164 Head broader than elytra, paratergites indistinctly delimited, extinguishing.: E (fig.21). 4.5-5.2mm (FB 2.2mm). China (Taiwan) ............................. S. pseudolus PUTHZ

- Head narrower than elytra, paratergites narrow but distinctly delimited.: E (fig. 7). 4.0- 5.5mm (FB 2.7mm). China ( Taiwan, Hainan, Guangdong, Hongkong, Fujian, Chongqing, Jiangsu), Vietnam, Japan......................................... S. formosanus L. BENICK

165 Legs predominantly reddish..........................................................................................166

- Legs black or predominantly dark brown to black........................................................172

166 Smaller, FB <2.2mm .....................................................................................................167

- Larger, FB t 2.2mm ......................................................................................................169

note: S. sauteri BERNHAUER (E: fig. 13), known from Russia (Far East) and Japan, would run here

167 Elytra with a small rosetta of curved sulci medially.: Metafemur with a basal spine (fig. 6). E (fig.16). 3.8-4.5mm (FB 2.0mm). China (Sichuan, Yunnan) ............................. ............................................................................................................ S. spinulipes PUTHZ

- Elytra without a small rosetta medially........................................................................168

168 Abdominal punctuation coarser, punctures on tergite 7 larger or as large as basal cross section of antennal segment 3.: Metafemora without or with a basal spine.....169

- Abdominal punctuation finer, punctures on tergite 7 smaller than basal cross section of antennal segment 3.: Metafemur with a basal spine. E (fig.20). 3.0- 3.8mm (FB 1.8-1.9mm). China (Heilongjiang), Russia: Siberia, Far East), Japan................................ ................................................................................................... S. amurensis EPPELSHEIM

169 Abdominal punctation very coarse and very dense, punctures on tergite 7 about as large as medial cross section of antennal segment 3.: E (fig.24). 3.8-4.5mm (FB 2.0- 2.2mm). China (Henan, Shaanxi, Shanxi, Hebei, Beijing, Jilin, Heilongjiang, Ningxia, Gansu, Nei Mongol), Russia (Siberia, Far East), Mongolia, Korea..................... ...................................................................................................... S. secretus BERNHAUER

- Abdominal punctuation less coarse and less dense, punctures on tergite 7 distinctly smaller than medial cross section of antennal segment 3.: E (fig.15). 3.6-4.4mm (FB 1.8-2.1mm). China (Shanxi, Beijing, Jilin, Qinghai, Gansu), Russia (Siberia), Mongolia, Alaska, Yukon Territory................................ S. kamtschaticus MOTSCHULSKY

170 Head broader (HW: EW>0.88). Mostly smaller.: E (fig. 9). 4.0- 5.5mm (FB 2.1- 2.5mm). China (Liaoning, Heilongjiang), holarctis..................... S. clavicornis (SCOPOLI)

- Head less broad (HW: EW <0.87) Mostly larger..........................................................171

171 Punctation of pronotum and elytra less dense, not confluent.: Sternites 3-6 with conspicuous long lateral brushes, apical portion of median lobe deeply emarginated.

5.0- 5.5mm (FB 2.7-2.8mm). China ("NE China ", Heilongjiang), Russia (Far East), Japan........................................................................................... S. indagator EPPELSHEIM

- Punctation of pronotum and elytra denser, occasionally confluent.: Sternites 3-6 without conspicuous lateral brushes; apical portion of median lobe broadened and shallowly emarginated. 4.6-6.0mm (FB 2.8mm). China (Heilongjiang), Russia (Far East)................................................................................................. S. ussuriensis RYVKIN

172 Larger, FB 2.2-2.8mm ..................................................................................................173 - Smaller, FB <2.2mm .....................................................................................................174

note: S. taigae POPPIUS ( Russia: Siberia, Far East, E: fig.11) and S. intrusus CASEY ( Russia: Siberia, Far East, E: fig.12) would run here

173 Interstices of abdominal punctuation shallowly reticulate. Longitudinal furrows of frons deep and sharp, median portion strongly elevated.: Apex of median lobe deeply excised. 4.5-6.5mm (FB 2.6-2.8mm). China (Shanxi, Heilongjiang, Ningxia), holarctis ................................................................................................ S. juno (PAYKULL)

- Interstices of abdominal punctuation smooth. Longitudinal furrows of frons shallow, median portion shallowly elevated.: Apex of median lobebroadly rounded (fig. 8). 3.6-5.8mm (FB 2.1-2.6mm). China (Sichuan, Xizang, Qinghai, Gansu, Xinjiang), Kazakhstan, Turkmenistan, Tadzhikistan, Uzbekistan, Kyrgyzstan, Iran, Afghanistan, Pakistan, Ladakh, Kashmir, SE Russia.................................... S. mongolicus EPPELSHEIM

174 Pronotum and elytra denser punctate, interstices much smaller than halfdiameter of punctures.: Apex of median lobe with distinct setae (figs 13, 19, 20, 22, 24)..........175

- Pronotum and elytra less dense punctate, interstices nearly as wide as half diameter of punctures or wider.: Apex of median lobe without distinct setae (fig.23). 3.5- 3.8mm (FB 1.8-2.1mm). China (Zhejiang, Shanghai, Jiangsu, Henan, Shaanxi, Shanxi, Tianjin, Hebei, Beijing, Liaoning, Heilongjiang), Korea...................................... .................................................................................... S. lewisius pseudoater BERNHAUER

175: E (fig.22). In average larger. 3.3-4.0mm (FB 1.9-2.0mm). China (Heilongjiang, Nei Mongol), northern holarctis ............................................. S. fasciculatus J. SAHLBERG

-: E (fig.19). In average smaller. 3.9- 3.7mm (FB 1.6-1.8mm). China (Shaanxi, Shanxi, Beijing, Liaoning, Jilin, Heilongjiang, Qinghai, Nei Mongol), Russia (Far East)........................................................................................... S. paradoxus BERNHAUER

176 Elytra longer (EW: EL =1.00-1.12)..............................................................................177

- Elytra shorter (EW: EL =1.14-1.35).............................................................................180

177 Smaller, 2.5-2.9mm (FB 1.5-1.7mm)............................................................................178

- Larger, 3.0- 4.2mm (FB 1.7-2.1mm).............................................................................179

178 Elytral punctuation regular.: Expulsion clasp of median lobe (fig. 31). 2.5-2.9mm (FB 1.5-1.6mm). China (Liaoning, Jilin, Heilongjiang), Russia (Far East) ........................ ............................................................................................................ S. hammondi PUTHZ

- Elytral punctuation occasionally irregular.: Expulsion clasp of median lobe (fig. 34). 2.7-2.9mm (FB 1.7mm). China (Fujian)............................... S. kuatunensis L. BENICK

179 Punctation of pronotum and elytra very dense, often slightly rugose.: Expulsion clasp of median lobe (fig. 33). 3.0-4.0mm (FB 1.7-2.1mm). China (Guizhou, Fujian, Hubei, Jiangxi, Zhejiang, Shanghai, Jiangsu, Anhui, Shaanxi, Shanxi), Korea, Japan....... ............................................................................................................. S. japonicus SHARP

- Punctation of pronotum and elytra dense, not rugose, very regular.: Expulsion clasp of median lobe (fig. 32). 3.3-4.2mm (FB 1.8-2.1mm). China (Zhejiang, Shanghai).................................................................................... S. proclinatus L. BENICK

180 Abdominal punctuation coarser and denser, punctures on tergite 7 larger or about as large as basal cross section of antennal segment 3.......................................................181

- Abdominal punctuation less coarse, punctures on tergite 7 smaller than basal cross section of antennal segment 3, interstices distinctly wider than half diameter of punctures.: Expulsion clasp of median lobe (fig. 35). 3.0- 3.5mm (FB 1.6-1.7mm). China (Heilongjiang), Russia (Far East) ...................... S. mammops bulbicollis L. BENICK

181 Elytra very short (EW: EL a1.30).: E with expulsion clasp of median lobe (fig.28). 3.0- 3.4mm (FB 1.6-1.7mm). Russia (Far East)...............................[ S. puthzi HROMADKA ]

- Elytra less short (EW: EL d1.20)..................................................................................182

182 Fore parts matt, punctuation extremely dense, abdominal punctuation coarser and denser.: E and expulsion clasp of median lobe (fig. 29). 3.3-4.1mm (FB 1.6-1.7mm). China (Shanxi, Heilongjiang, Ningxia, Gansu)..................... S. asprohumilis ZHAO & ZHOU

- Fore parts slightly shiny, punctuation (although very dense) slightly less dense, abdominal punctuation less coarse and less dense.: Expulsion clasp of median lobe (fig. 36). 3.0- 3.5mm (FB 1.6-1.7mm). China (? Heilongjiang), Korea, Russia (Siberia, Far East), North America................................................... S. mammops mammops CASEY

183 Segment 1 of maxillary palpi dark briown to black; pubescence of elytra conspicuous, silvery, tortuous. Apicolateral tooth of sternum 9 strongly curved inwards (fig. 2).: E (fig. 39). 3.0-4.0mm (FB 1.8-2.0mm). Palaearctic, China (Shaanxi, Shanxi, Jilin, Liaoning, Heilongjiang), Russia (Siberia, Far East), Korea, Japan.... ............................................................................................................ S. ruralis ERICHSON

- Segment 1 of maxillary palpi yellow or reddish yellow; pubescence of elytra inconspicuous. Apicolateral tooth of sternum 9 nearly straight or less curved inwards.: With or without sclerotized spermatheca................................................................184

184 Pronotum with a longitudinal furrow medially (furrow may become very narrow and sometimes slightly distinct).: With a distinctly sclerotized spermatheca (figs 25, 26).................................................................................................................................185

- Pronotum without a longitudinal furrow medially.: With or without a distinctly sclerotized spermatheca................................................................................................191

185 Frons without longitudinal furrows..............................................................................186

note: S. vinnulus CASEY, E (fig. 49) (northern holarctic; Russia: Siberia, Far East) would run here

- Frons with ± distinct longitudinal furrows....................................................................189

186 Tergite 7 deeply and densely reticulate.: E (fig. 48). 3.5-4.5mm (FB1.8-2.0mm). China (Liaoning, Heilongjiang), Russia (Siberia, Far East), Mongolia.............................. ............................................................................................................... S. illotulus PUTHZ

- Tergite 7 without or only with very shallow reticulation..............................................187

187 Anterior margin of labrum simple. Punctation of forebody coarser, punctures of frons distinctly smaller than apical cross section of antennal segment 2.: E (fig. 46). 2.9- 3.5mm (FB 1.6-1.8mm). China (Heilongjiang), Russia (Far East), Japan.......................... ................................................................................................................ S. raddei RYVKIN

- Anterior margin of labrum with a small notch (difficult to ascertain). Punctation of fore body less coarse, punctures of frons about as large as apical cross section of antennal segment 3.Two species which should be identified by their aedeagus...........188

188: E (fig. 44), apical portion of median lobe less pointed.: S (fig. 26) 2.7-4.3mm (FB 1.6-1.9mm). Holarctic, China (Shanxi) ......................... S. canaliculatus GYLLENHAL

-: E (fig. 45), apical portion of median lobe more pointed. 4.0mm (abdomen extended) [from RYVKIN 2012]. China (Xinjiang Uiguhr)................... S. canosus RYVKIN

189 Pronotum broader as long or as broad as long.: E (fig. 50).: S (fig. 25). 2.3- 3.4mm (FB 1.6-1.8mm). Europe (holomediterraneous), E North America (introduced). China (Liaoning).......................................................... S. melanopus (MARSHAM)

- Pronotum longer than broad.........................................................................................190

190 Larger: 4.0- 4.8mm (FB 2.2-2.4mm). Head broader (HW: EW t0.84).: E (fig. 43). China (Heilongjiang), Russia (Far East)................................................. S. illusor RYVKIN

- Smaller: 2.9-4.0mm (FB 1.8-1.9mm). Head less broad (HW: EW d0.82).: E (fig. 46). China (Taiwan) .......................................................................... S. immigratus PUTHZ

191: Median lobe longer than parameres, apex pointed.: No sclerotized spermatheca. Punctation of forebody regular to irregular..................................................................192

-: Median lobe as long as parameres, apex rounded (fig. 42). 2.3-3.3mm (FB 1.3- 1.6mm). Holarctic, China (Heilongjiang) .................................................. S. ageus CASEY

192 Head broader (HW: EW =0.72-0.82). 3 variable species which should be identified by their aedeagi.............................................................................................................193

- Head less broad (HW: EW =0.68-0.75).: E (fig. 38).2.8-4.0mm (FB 1.6-1.9mm). Palaearctic, China (Heilongjiang, Nei Mongol)........................... S. incrassatus ERICHSON

193: E (fig. 41). Elytral punctation (often) occasionally coalescent, interstices mostly distinctly reticulate. Head mostly slightly narrower than elytra. 3.0- 4.1mm (FB 1.6- 1.9mm). Palaearctic, China (Jilin, Nei Mogol) ........................................ S. boops LJUNGH

- otherwise. Elytral punctuation more regular, (mostly) not coalescentinterstices mostly without groundsculpture. Head mostly distinctly narrower than elytra............194

194: E (fig. 40). Longitudinal furrows of frons more distinct, median portion of frons extending to or exceeding the level of medial eye margins..........................................195

-: E (fig. 37). Longitudinal furrows of frons less distinct, almost indistinct, median portion not extending to the level of medial eye margins.2.0-4.0mm (FB 1.4-1.8mm). Holarctic, China (Shaanxi, Shanxi, Hebei, Liaoning, Heilongjiang, Qinghai, Gansu) ....... ...................................................................................................... S. morio GRAVENHORST

195 In average denser punctate, middle of pronotum densely punctate, interstices smaller than half diameter of punctures. 2.4-3.5mm (FB 1.4-1.7mm). Holarctic, China (Sichuan, Yunnan, Guizhou, Hainan, Fujian, Taiwan, Hunan, Jiangxi, Zhejiang, Shanghai, Jiangsu, Henan, Shanxi, Shaanxi, Tianjin, Liaoning, Ningxia).......................... .................................................................................. S. melanarius melanarius STEPHENS

- In average less densely punctate, interstices in the middle of pronotum wider than half diameter of punctures, sometimes as large as punctures or still larger. 2.4-3.5mm (FB 1.4-1.7mm). India, Nepal, Myanmar, Thailand, Laos, Vietnam, China (Yunnan), Indonesia (Timor), Philippines....................................... S. melanarius annamita FAUVEL

196 Base of abdominal tergites with 4 short carinae. Abdomen less densely punctate, interstices wider than half diameter of punctures. Elytra longer than pronotum..........197

- Base of abdominal tergites without short carinae. Abdominal punctuation coarse and very dense, interstices smaller than half diameter of punctures. Elytra as long as pronotum.: Unknown. 2.8-3.4mm (FB 1.3-1.7mm) China (Qinghai, Gansu)................. ........................................................................................................... S. gansuensis PUTHZ

note: S. nubilus RYVKIN and S. strobilus RYVKIN (elytra longer than pronotum,: E (figs 1, 2, RYVKIN 2002) ( Russia: Siberia, Far East, Japan) would run here

197 Elytra and abdomen with long and dense, erect pubescence........................................198

- Elytra and abdomen without long and dense, erect pubescence.: E (fig. 53).: S (fig.27).2.3-3.0mm (FB 1.3-1.4mm). China (Shanxi, Nei Mongol), Korea, Russia (Far East), North America.................................................................. S. immarginatus MÄKLIN

note: S. finalis RYVKIN (: E (fig. 52) from Russia (Far East) would run here

198 Elytra much broader than head (EW: HW>1.25) and nearly as long as broad; punctuation less coarse.: E (fig. 51).: S (about as in fig.27). 2.5-3.2mm (FB 1.3- 1.6mm). China (Sichuan, Jiangxi, Zhejiang, Shanghai, Jiangsu, Shanxi, Shaanxi, Shandong, Hebei, Beijing, Liaoning, Heilongjiang, Gansu, Ninxia), Korea, Russia (Far East) ................................................................................ S. pilosiventris BERNHAUER

- Elytra less broad (EW: HW <1.17), distinctly broader than long; punctation coarser.: E about as in fig. 51, apical portion of median lobe less spade shaped.: S (about as in fig.27). 2.4-2.9mm (FB 1.4-1.5mm). China (Zhejiang, Shaanxi, Shanxi), Japan....... ........................................................................................................... S. hirtiventris SHARP

199 The key of the Chinese Stenus species has to be continued here with the species, which have the tarsal segment 4 bilobed.