Stenus absconditus Hu & Tang, 2018

Hu, Cheng-Zhi & Tang, Liang, 2018, Notes on the Stenus indubius group with descriptions of four new species from China (Coleoptera, Staphylinidae), Zootaxa 4471 (2), pp. 341-350 : 347-348

Stenus absconditus Hu & Tang , sp. n.

( Figs. 4 , 23–28 )

Type Material. Holotype: China: Guizhou: ♂, glued on a card with labels as follows: “ China: Guizhou Prov., Xishui County, Sanchahe , 28°30'01''N, 106°24'12''E, 890m, 12.VII.2015, Jiang, Peng, Tu & Zhou leg.” “ Holotype / Stenus absconditus / Hu & Tang” [red handwritten label] ( SHNU) . Paratypes: 5♂♂ 3♀♀, same data as for the holotype. ( SHNU, cPut)

Description. Brachypterous; body blackish, anterior margin of labrum, antennae, maxillary palpi and legs yellowish brown, each elytron with a oval orange spot, which is about 1/3 as long as and 1/3 as broad as the respective elytron.

BL: 4.3–4.8mm, FL: 2.1–2.4 mm.

HW: 0.86–1.01 mm, PL: 0.71–0.78 mm, PW: 0.64–0.74 mm, EL: 0.70–0.83mm, EW: 0.76–0.92 mm, SL: 0.48–0.56mm

Head 1.10–1.14 times as wide as elytra; interocular area with deep longitudinal furrows, median portion convex, extending to the level of inner eye margins; punctures round, partly confluent, slightly larger and sparser on median area than those near inner margins of eyes, diameter of large punctures about as wide as apical cross section of antennal segment II; interstices partially and indistinctly reticulated, much smaller than half the diameter of punctures except those along the midline of convex median portion, which may be a little larger than half the diameter of punctures. Paraglossa oval.

Pronotum 1.04–1.10 times as long as wide; disk relatively uneven, with shallow median longitudinal furrow, subbasal and subapical impressions indistinct; punctures more or less confluent, slightly larger than those on head; interstices rarely with indistinct reticulations, narrower than half the diameter of punctures except for those in the middle of the median longitudinal furrow, which may be as wide as the diameter of punctures.

Elytra 0.89–0.94 times as long as wide; disk uneven with distinct longitudinal humeral impression, distinct sutural impression and distinct posterolateral impression, suture convex; punctation and interstices similar to those of pronotum except the punctures are a little larger in average.

Legs with tarsomeres IV deeply bilobed.

Abdomen cylindrical; segments III–VI without paratergites, tergites and sternites distinctly separated by lateral sutures; posterior margin of tergite VII with apical membranous fringe; punctation of abdominal tergites elliptic to round, gradually becoming smaller posteriad, punctures in posterior portions of tergite III smaller than those of head in average; interstices of tergites shallowly microsculptured, slightly narrower than half the diameter of punctures to wider than diameter of punctures.

Male. Sternite VII with indistinct emargination in the middle of posterior margin; sternite VIII ( Fig. 23 ) with shallow emargination in the middle of posterior margin; sternite IX ( Fig. 24 ) with very long apicolateral projections, posterior margin serrate. Aedeagus ( Figs. 25, 26 ) with median lobe stout, apical sclerotized area short, pointed at apex; expulsion clasps large; parameres as long as median lobe, swollen at apical sixth, each with 9–13 setae on apico-internal margins.

Female. sternite VIII ( Fig. 27 ) slightly prominent at middle of posterior margin; spermatheca ( Fig. 28 )sclerotized, spermathecal duct with two bents, apical chamber large and capsule very large.

Distribution. China (Guizhou).

Remarks. The new species is very similar to S. zhaiyanbini Tang & Li, 2012 from Guizhou, and can be distinguished from the latter by head and pronotum hardly with microsculptures, elytra slightly shorter and elytra spots smaller.

Etymology. The specific name “ absconditus ” means hidden.

Figures

FIGURES 3, 4. Habitus. 3 Stenus fuscus 4 S. absconditus. Scale bars: 1mm.

FIGURES 23–28. Stenus absconditus. 23 male sternite VIII 24 male sternite IX 25, 26 aedeagus 27 female sternite VIII 28 valvifers and spermatheca. Scale bars: 0.25mm.