Discovery of Steninae from Ningxia, Northwest China (Coleoptera, Staphylinidae)

Abstract A study on the Steninae of Ningxia Autonomous Region is presented. Sixteen species are recognized, including new province records for 11 species and four new species: Stenus biwenxuani sp. n., Stenus liupanshanus sp. n., Dianous yinziweii sp. n., Dianous ningxiaensis sp. n. Habitus photos of the new species, illustrations of diagnostic characters of all species and a key to species of the Steninae recorded from Ningxia are provided.


Introduction
Steninae, comprising two genera Stenus Latreille, 1797 and Dianous Leach, 1819, is a speciose subfamily of Staphylinidae. So far, 296 Stenus species and 103 Dianous species have been recorded from China. As far as the Steninae are concerned, Ningxia Autonomous Region is one of the most poorly explored regions, with merely two species recorded (Puthz 2008b): Stenus deceptiosus Puthz, 2008 and Stenus comma Leconte, 1863. In the summer of 2008, a team surveyed the insect fauna of the Liupan Shan Natural Reserve in southern Ningxia and collected a large number of Steninae. In this paper, we report the results of the study on that material, which includes two new Stenus and two new Dianous species, and new province records for eleven Stenus species.

Material and methods
The specimens examined in this paper were collected by sifting leaf litter in forests and killed with ethyl acetate. For examination of the male genitalia, the last three abdominal segments were detached from the body after softening in hot water. The aedeagi, together with other dissected pieces, were mounted in Euparal (Chroma Gesellschaft Schmidt, Koengen, Germany) on plastic slides. Photos of sexual characters were taken with a Canon G7 camera attached to an Olympus SZX 16 stereoscope; habitus photos were taken with a Canon macro photo lens MP-E 65 mm attached to a Canon EOS40D camera.
Only records published after 2000 are given in the list of synonyms of each species. Articles published prior to 2001 may be found in Herman 2001.
The type specimens treated in this study are deposited in the following public and private collections: cPut private collection V. Puthz, Schlitz, Germany SHNU Department of Biology, Shanghai Normal University, P. R. China The measurements of proportions are abbreviated as follows:

BL
body length, measured from the anterior margin of the clypeus to the posterior margin of abdominal tergite X FL forebody length, measured from the anterior margin of the clypeus to the apical margin of the elytra (apicolateral angle) HW width of head including eyes PW width of pronotum EW width of elytra PL length of pronotum EL length of elytra, measured from humeral angle SL length of elytral suture taxonomy Key to the species of Steninae of Ningxia

Diagnosis.
The new species belongs to the Stenus comma group, and is similar to Stenus atrovestis Puthz, 2008(Puthz 2008b. However it can be easily distinguished from the latter by the reddish brown legs, longer elytra and simple metatibiae (S. atrovestis with black legs, shorter elytra and flattened metatibiae).
Description. Body blackish with a faint plumbeous luster, antennae dark brown with club darker, maxillary palpi yellowish with last and apical half of penultimate segments brownish, legs reddish brown except knee darker with a faint plumbeous luster.
Head 0.90 times as wide as elytra; interocular area with deep longitudinal furrows, median portion moderately convex, not reaching the level of inner eye margins; punctures round, extremely dense, and of similar size; diameter of punctures about as wide as apical cross section of antennal segment III; interstices much narrower than half the diameter of punctures except those along the midline of the convex median portion, which may be a little broader than half the diameter of punctures. Antennae, when reflexed, extending a little beyond middle of pronotum; relative length of antennal segments from base to apex as 12 : 10 : 17.5 : 10: 9 : 6.5 : 7: 5 : 6 : 6 : 10. Paraglossa oval.
Pronotum 1.06 times as long as wide; disc with shallow and broad median longitudinal furrow fused with pairs of shallow impressions in anterior half, in the middle, and in posterior half; punctures round and very dense, slightly confluent, a little larger than those of head; interstices partially reticulated, of variable width, as wide as half the diameter of punctures or narrower.
Elytra 1.04 times as long as wide; disc slightly uneven with indistinct longitudinal humeral impression, indistinct postero-lateral impression, and indistinct sutural impression; punctures mostly confluent, a little larger than those of pronotum with rugose interstices.
Hind tarsi 0.76 times as long as hind tibiae, tarsomeres IV simple. Abdomen semi-cylindrical with broad, raised and densely punctate paratergites of segments III-VI, width of paratergites of segment III slightly broader than apical width of metatibiae, punctures slightly larger than those on median portion of tergites; posterior margin of tergite VII with palisade fringe; punctures on abdominal tergites III-VIII round to elliptic, very dense, gradually becoming smaller posteriad; interstices mostly as wide as half the diameter of punctures at most, with relatively faint reticulation on all abdominal tergites.
Male. Mesotibiae and metatibiae each with a subapical tooth on inner side; sternite VI impressed postero-medially with a shallow emargination along the posterior margin of the impression; sternite VII impressed medially, posterior margin of this impression emarginate; sternite VIII ( Fig. 26) with emargination at middle of posterior margin; sternite IX ( Fig. 27) with apico-lateral projections long and stout, posterior margin serrate; tergite X ( Fig. 28) with posterior margin slightly emarginated. Aedeagus (Figs 29, 30) slender, median lobe with a very long and pointed apex; internal plate strongly sclerotized (Fig. 31), parameres extending beneath apex of median lobe, widened and folded in apical third, each with 18 setae on inner side.

Distribution. China (Ningxia).
Etymology. This species is named in honor of Mr. Wen-Xuan Bi, the collector of the new species. Head 1.02-1.04 times as wide as elytra; interocular area with deep longitudinal furrows, median portion convex, slightly extending beyond the level of inner eye margins; punctures round, moderately confluent, and of similar size, diameter of punctures about as wide as apical cross section of antennal segment III; interstices rugose with indistinct reticulation, much narrower than half the diameter of punctures except those along the midline of the convex median portion, where they may be slightly broader than diameter of punctures. Antennae, when reflexed, not reaching middle of pronotum; relative length of antennal segments from base to apex as 6: 5.5: 8: 5: 5: 4: 3: 2.5: 4: 4: 5.5. Paraglossa oval.

Stenus liupanshanus
Pronotum 0.91-0.93 times as long as wide; disk somewhat flattened, with shallow median longitudinal furrow; punctures slightly confluent, a little larger than those of head; interstices reticulated, distinctly narrower than half the diameter of punctures. Elytra 0.75-0.79 times as long as wide, distinctly constricted at base; lateral margins gently divergent posteriad; disk rather even, suture slightly convex; punctation and interstices similar to those of pronotum.
Legs with hind tarsi 0.68 times as long as hind tibiae, tarsomeres IV distinctly bilobed.
Abdomen cylindrical; distinct paratergites absent, but rudimentary lateral border present; posterior margin of tergite VII with palisade fringe; punctures of abdominal tergites III-VIII elliptic, gradually becoming smaller posteriad; interstices narrower than half the diameter of punctures, with relatively faint microsculpture on tergites III-VII and distinct reticulation on tergites VIII-X.
Female. Abdomen broader than that of male; sternite VIII ( Fig. 38) slightly produced in the middle of posterior margin; tergite X ( Fig. 39) similar to that of male; sclerotized spermatheca bent twice with many bubble structures on second tube (Figs 40, 41).

Distribution. China (Ningxia).
Etymology. The specific name is derived from "Liupanshan", the mountain where the type specimens were found.

Dianous inaequalis inaequalis Champion, 1919
http://species-id.net/wiki/Dianous_inaequalis_inaequalis Fig. 24 Dianous inaequalis Champion, 1919: 45. Dianous caeruleoguttatus Cameron, 1927.  Bernhauer, 1915 in sharing the elytral spots reaching the lateral margins in dorsal view. However, it can be easily distinguished from the latter by the distinctly smaller body size and the faint metallic luster of the entire body, which is strongly metallic blue in D. banghaasi.
Description. Body black with a plumbeous luster, antennal club brownish, elytra each with a large transverse orange spot, which reaches the lateral margins of the elytra in dorsal view, and with a narrow band of coppery luster around the spot, pubescence silvery to golden brown throughout, that of elytral spots golden brown.
BL: 4.8-5.1mm; FL: 2.5-2.8 mm. HW: 0.98-1.04 mm, PL: 0.83-0.85 mm, PW: 0.77-0.82 mm, EL: 1.17-1.22 mm, EW: 1.07-1.16 mm, SL: 0.98-1.00 mm Head 0.85-0.94 times as wide as elytra; interocular area with deep longitudinal furrows, median portion convex; punctures round, slightly confluent along the furrows, larger and sparser in median area than those near inner margins of eyes, diameter of large punctures about as wide as apical cross section of antennal segment III; interstices smooth, much narrower than half the diameter of punctures. Antennae, when reflexed, extending distinctly beyond posterior margin of pronotum; relative length of antennal segments from base to apex as 13.5: 9: 20: 14: 13.5:12: 11.5: 11: 11: 10: 12.5. Pronotum 1.03-1.08 times as long as wide; disk relatively even; punctures round, transversely confluent in posterior portion, a little larger than those on head; interstices smooth, narrower than half the diameter of punctures except those in median portion, which may be as broad as two or three punctures. Elytra 1.03-1.09 times as long as wide; punctation and interstices similar to those of pronotum, except that punctation of basal half portion and along suture is distinctly confluent with rugose interstices.
Hind tarsi with tarsomeres IV distinctly bilobed. Abdomen semi-cylindrical with broad, raised and densely punctate paratergites of segments III-VI, width of paratergites of segment III as broad as apical width of metatibiae, punctures minute; posterior margin of tergite VII with palisade fringe; punctures on abdominal tergites III-VIII minute, smaller than ommatidia of eyes; interstices without microreticulation except tergite VIII, varied from a little narrower than half the diameter of punctures to much broader than diameter of punctures.
Pubescence of fore body long and suberect, single setae as long as fourth antennal segment.
Male. Sternite VII impressed postero-medially with shallow emargination along posterior margin of the impression; sternite VIII ( Fig. 42) with deep emargination in the middle of posterior margin; sternite IX ( Fig. 43) with apicolateral projections mod-erately pointed and posterior margin serrate; tergite X ( Fig. 44) with posterior margin slightly emarginated. Aedeagus (Fig. 45) with median lobe bilobed at apex; parameres slightly bent inwards, extending distinctly beyond the apex of median lobe, with setae on inner side of apical portion.
Female. Abdomen slightly broader than that of male; sternite VIII ( Fig. 46) distinctly produced in the middle of posterior margin; valvifer ( Fig. 47) with posterior margin finely serrate; tergite X ( Fig. 48)  Diagnosis. The new species belongs to the Dianous chinensis complex and is similar to Dianous chinensis Bernhauer, 1915 (Fig. 25). It can be easily distinguished from the latter by the extremely large elytral spots and distinctly longer parameres of the aedeagus.
Description. Body black with a blue to purple metallic luster, antennal club brownish, each elytron with a large elongate orange spot, which is 1/2 as long as and  Head 0.77 times as wide as elytra; interocular area with deep longitudinal furrows, median portion convex; punctures round, similar in size, diameter of punctures about as wide as basal cross section of antennal segment III; interstices without microsculpture and of variable width, ranging from being narrower than half the diameter of punctures to being of similar width as diameter of punctures. Antennae, when reflexed, extending distinctly beyond posterior margin of pronotum; relative length of antennal segments from base to apex as 16: 9.5: 34.5: 16.5: 18: 15.5: 15.5: 15: 14: 12: 13. Pronotum 1.04 times as long as wide; disk uneven, with two deep median impressions fused with a distinct basal impression; punctures mostly well delimited, slightly larger than those on head; interstices without microreticulation and of variable width.
Elytra 1.11 times as long as wide; punctation and interstices similar to those of pronotum except for a few larger punctures and partly fainly microsculptured interstices.
Hind tarsi with tarsomeres IV distinctly bilobed. Abdomen semi-cylindrical with broad, raised and densely punctate paratergites of segments III-VI, paratergites of segment III slightly broader than apical width of metatibiae, punctures minute; posterior margin of tergite VII with palisade fringe; punctures on abdominal tergites III-VIII minute, smaller than ommatidia of eyes; interstices without microsculpture, except those of sternite VIII and of variable width.
Pubescence of fore body conspicuously long and suberect, single setae as long as fourth antennal segment.
Female. Unknown. Distribution. China (Ningxia). Etymology. The specific name is derived from "Ningxia", the type locality of this species.