Stenus cariniventris Tang, Liu & Dong, 2018

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 : 528-530

Stenus cariniventris Tang, Liu & Dong , new species

(Figs 1, 8–15)

Material examined. Holotype: ♂, glued on a card with labels as follows: “ China: Sichuan, Dayi County, Xiling Xueshan , 30°41'59''N, 103°12'10''E, mixed leaf litter, sifted, 2150 m, 29.VII.2015, Jiang, Peng, Tu & Zhou leg” . “Holotype / Stenus cariniventris / Tang, Liu & Dong” [red handwritten label] (SHNU). Paratypes: 18♂♂ 15♀♀, same data as for the holotype. ( SHNU, cPut) ; 2♂♂ 3♀♀, Sichuan, Mt. Qingchengshan, Baiyun Temple , 30°56'N, 103°28'E, alt. 1700 m, 30.VII.2012, Peng, Dai & Yin leg. ( SHNU) ; 2♂♂ 2♀♀, same locality, alt. 1650 m, 29.VII.2012, Peng, Dai & Yin leg. ( SHNU) ; 1♂ 1♀, same locality, alt. 1900–2000m, 30.VII.2012, Peng, Dai & Yin leg. ( SHNU).

Description. Brachypterous; head black, other body parts dark brown, each elytra with median portion inconspicuously to conspicuously lighter. Antennae, maxillary palpi and legs yellowish brown except antennal club infuscate. Labrum reddish brown.

BL: 4.6–5.2 mm, FL: 2.0– 2.3 mm.

HW: 0.77–0.95 mm, PL: 0.64–0.75 mm, PW: 0.60–0.71 mm, EL: 0.65–0.78 mm, EW: 0.68–0.85 mm, SL: 0.50–0.60 mm.

Head 1.08–1.16 times as wide as elytra; interocular area with two deep longitudinal furrows, median portion convex, reaching the level of inner eye margins; punctures round, slightly larger and sparser on median portion than those near inner margins of eyes, diameter of large punctures about as wide as apical cross section of antennal segment II; interstices smooth, narrower than half the diameter of punctures except those along the midline of the median portion, which may be 1.5–2 times wider than the diameter of punctures. Paraglossae oval.

Pronotum 1.01–1.08 times as long as wide; disk uneven, with distinct median longitudinal furrow almost throughout, two shallow impressions in anterior half, two shallow impressions in about middle, two shallow impressions in posterior half; punctures confluent, slightly larger in size than those of head; interstices smooth, much narrower than half the diameter of punctures except for those in the middle of the median longitudinal furrow, which may be triple as wide as the diameter of punctures.

Elytra 0.89–0.99 times as long as wide; disk uneven with deep longitudinal humeral impression, distinct postero-lateral impression and distinct sutural impression, suture moderately convex; punctures longitudinally confluent, similar size to those on pronotum; interstices smooth, distinctly smaller than half the diameter of punctures.

Legs with tarsomeres IV strongly bilobed.

Abdomen cylindrical; paratergites very narrow and almost impunctate, present only in segment III, tergites and sternites totally fused in segments IV–VI, posterior margin of tergite VII with indistinct apical membranous fringe; punctation of tergites III–VIII sparse and shallow, gradually becoming smaller posteriad; interstices smooth, mostly wider than diameter of punctures except those on basal impressions of tergites III–V, which may be distinctly narrower than half the diameter of punctures.

FIGURES 1–7. Habitus. 1 Stenus cariniventris 2 S. jiangrixini 3 S. lineatus 4 S. emeishanus 5 S. jiudingshanus 6 S. xichangensis 7 S. brevilineatus . Scale bars: 1mm.

Male. Sternite VII with posteromedian portion slightly impressed; sternite VIII ( Fig. 8 ) with distinct semicircular emargination at middle of posterior margin; sternite IX ( Fig. 9 ) with long apicolateral projections, posterior margin serrate. Aedeagus ( Figs.10–12 ) with median lobe varied in width, apical sclerotized area triangular with mid ridge ( Fig. 13 ) strongly convex and varied in width ( Figs 10, 11 ); expulsion clasps very large, strongly sclerotized; parameres indistinctly shorter than median lobe, swollen at apical parts, each with 10–13 setae on apico-internal margins.

Female. Sternite VIII ( Fig. 14 ) entire; strongly sclerotized spermatheca ( Fig. 15 ) with basal porch and spermathecal duct bent twice.

Distribution. China (Sichuan).

Remarks. The species can be distinguished from other species by the following characters: body size larger, surfaces of pronotum and elytra rather uneven and the distinctly median longitudinal furrow of pronotum.

Etymology. The specific name is derived from the presence of mid ridge on apical portion of aedeagal median lobe.

Figures

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.