Contributions to the knowledge of the Quediina (Coleoptera, Staphylinidae, Staphylinini) of China. Part 51. Genus Quedius STEPHENS, 1829. Subgenus Distichalius CASEY, 1915. Section 4 Author Smetana, Aleš text Linzer biologische Beiträge 2015 2015-07-31 47 1 905 924 journal article 10.5281/zenodo.5415636 0253-116X 5415636 Quedius ( Distichalius ) causarius nov.sp. ( Figs 16-23 ) T y p e l o c a l i t y China : Qinghai , Lang Shi Dang Jing Qu (Park), 75 km NW Honggu, 36°54’05.2"N 102°21" 07.1E , 2925 m . T y p e m a t e r i a l Holotype (3): CHINA : " CHINA : Qinghai Prov. [CH 11-11a] Lang Shi Dang Jing Qu ( Park ), 75 km NW Honggu , 2925 m , 36°54’05.2"N 102° 21" 07.1E , creek on overgrown scree, Populus and Betula for. with Rhodod., litter, 28.VI.2011 , leg. Schülke " . Allotype ( ♀ ): samed data as holotype . Holotype in MSC, allotype in ASC. Paratypes : same data as holotype, 333, 2♀♀ ( ASC , MSC ) ; same, but 2896 m , 36°54’08.8"N 102°21’16.9"E , 28.VI.2011 , [ CH 11- 11], leg. Schülke , 4♀♀ ( ASC , MSC ) ; same, but D.W. Wrase , 2♀♀ ( MSC ) ; Qinghai , road 301 km 180, 43 km ESE Men Yuan , 37°09.32.6N 102°02’06.0"E , 2704 m , 5.VII.2011 , [ CH 11-19], M. Schülke , 2♀♀ ( MSC ) . D e s c r i p t i o n: In all characters similar to Q. menippus SMETANA, 2008 and different only by the different aedoeagus and tergite 10 of female genital segment. Male. First four segments of front tarsus markedly dilated, almost patellate, each densely covered with tenent setae ventrally; segment 2 markedly wider than apex of tibia (ratio 1.40), segment 4 markedly narrower than preceding segments. Sternite 8 rather densely setose, with two long setae on each side; with wide and deep medioapical emargination, small triangular area before emargination flattened and smooth ( Fig. 16 ). Genital segment with tergite 10 rather narrow, narrowed toward arcuate apex, with three or four long setae at apex, otherwise only sparingly setose ( Fig. 17 ); sternite 9 with wide and short basal portion, apical portion widely arcuate apically, with two slightly differentiated apical setae, otherwise finely setose ( Fig. 18 ). Aedoeagus ( Figs 19-22 ) rather large and robust; median lobe markedly, almost conically narrowed into narrowly arcuate apex, on face adjacent to paramere with short complex carina below apex; paramere large, shaped as in Figs 19 , 22 , with narrowly arcuate apex slightly exceeding apex of median lobe, with face adjacent to median lobe markedly excavate; two apical setae, one minute seta at each lateral margin below apex and two similar setae at each lateral margin still farther posteriad; sensory peg setae on underside quite small and few, usually three setae below apex and two or one on each side below apex, shifted quite close to lateral margin ( Fig. 22 ). Female. First three segments of front tarsus similar to those of male, but considerably less dilated; segment 2 about as wide as apex of tibia. Tergite 10 of genital segment quite characteristic, rather narrow with large pigmented middle portion and with distinct, setose medioapical carina and with numerous setae on apical portion, otherwise asetose ( Fig. 23 ). Length 6,0-7.0 mm. E t y m o l o g y: The specific epithet is the Latin adjective causarius , - a, -um (sickly, invalided). It refers to the drastic reduction of the sensory peg setae on the underside of the paramere. G e o g r a p h i c a l d i s t r i b u t i o n: The species is at present known from two localities in eastern Qinghai . B i o n o m i c s:Specimensoftheoriginalseriesweretakenonovergrownscreewith Populus and Betula forest with rhododendrons by sifting forest floor litter, and on another overgrown scree with Populus and Betula forest by sifting litter between rocks. Overgrown screes seem to be the preferred habitat of the species. R e c o g n i t i o n a n d c o m m e n t s Quedius causarius may be positively recognized only by the characteristic shape of the aedoeagus, including the location and the drastic reduction of both the number and size of the sensory peg setae on the underside of the paramere ( Fig. 22 ), a character state unique among the Distichalius -species, as well as by the characteristic development of tergite 10 of the female genital segment. The location and reduction of the number and size of the sensory peg setae on the paramere is apparently caused by the pronounced excavation of the face of the paramere adjacent to the median lobe.