Lesteva dabanensis Shavrin, Shilenkov & Anistschenko

Shavrin, Alexey V., Shilenkov, Viktor G. & Anistschenko, Alexander V., 2007, Two new species and additional records of Lesteva Latreille, 1797 from the mountains of South Siberia (Coleoptera: Staphylinidae: Omaliinae: Anthophagini), Zootaxa 1427, pp. 37-47 : 38-43

Lesteva dabanensis Shavrin, Shilenkov & Anistschenko , sp. n.

( Figs. 1 , 5–10 )

Holotype: RUSSIA: Republic of Buryatia: ɗ, “BURYATIA, Khamar-Daban Mts.: the upper of Osinovka (Mishikhinskaya) River [16 km SW Tankhoj], h=1600, 26– 31.07.1995, under stones at the edge of snow, leg. A. Shavrin” ( ZIN).

Paratypes: RUSSIA: Republic of Buryatia: 19ɗɗ, 14ΨΨ, same data as the holotype except leg. A. Shavrin & A. Anistschenko (cA, cS, IGU, ZIN); ɗ, 2ΨΨ, Khamar-Daban Mts., 6 km S Utulik, middle flow of the Babkha River, h= 500 m, 8–14.v.1999, mosses near a stream, A. Shavrin leg. ( IGU); 34ɗɗ, 43ΨΨ, Khamar-Daban Mts., 15 km S Utulik, upper reaches of the Babkha River, h= 600 m, 27.vi.2006, mosses near a stream, A. Shavrin leg. (cS); ɗ, 20 km SW of Baikalsk, valley of the Levaya Poperechnaya River, tributary of Babkha River, h= 950 m, 10–14.v.1999, mosses near a stream, leg. A. Shavrin ( IGU).

Description. Body 4.3–5.4 mm long, slender; legs long. Dark brown, suture and apex of elytra, legs, palpi and base of antennae yellowish brown. In some specimens sides of pronotum, base of elytra near scutellum, sides and suture of elytra brown. Body glossy, with dense and weak punctation, covered by goldish or grey setae. Habitus as in Fig. 1 .

Head large (LH:WH=3.7:3.3; LH:LP=3.7:4.1), broad, visibly narrower than pronotum, with oval convex compound eyes. Neck well developed behind rounded temples. Ocelli strongly reduced, poorly visible. Mouthparts strongly protruding. Labrum ( Fig. 7 ) transverse, straight or slightly emarginated at anterior edge, with numerous small setae and 6 large long setae. Mandibles long, slender, feebly curved, with bent apex and triangular tooth on cutting edge, with many setae on lateral edge of base ( Fig. 5 ). Lacinia almost straight, with row of short and strong setae on lateral edge, galea curved at apex, visibly longer than lacinia, with separate short setae at base and with apical brush of setae; stipes with row of setae on medial edge ( Fig. 6 ). Maxillary palpus long, last segment 2.5–3.0 times as long as penultimate. Antennae long, almost reaching middle of elytra, densely covered by fine setae. Length / width ratios of antennomeres as follows: I: 10:5; II: 6:3; III: 7:4; IV: 9:4; V: 9:4; VI: 9:4; VII: 9:4; VIII: 11:4; IX: 11:4; X: 10:4; XI: 14:4.

Punctation of head coarse and dense; punctation of pronotum fine and scattered; punctation of elytra large and sparse and sometimes slightly raised and rasplike. Microsculpture on vertex of head fairly coarse, almost isodiametric, in front part poorly visible or absent; pronotum and elytra without microsculpture, apical tergites of abdomen with short-transverse microsculpture.

Legs long, slender, densely covered by setae; tibia, especially in their apical part, with scattered spine-like setae. Metatarsus relatively short, 2.5 times shorter than tibia, first segment usually more or equal to last and 1.7–2.0 times longer than second segment. Ratio of length of segments of metatarsus: 10:4:4:3:10.

Surface of body, especially vertex, pronotum and elytra, densely covered by long white pubescence. Head densely punctate, with coarse microsculpture. Pronotum dense and finely punctate, with poorly visible microsculpture. Punctation of elytra dense, but points eroded, surface polished, without microsculpture. Abdomen mat, with fine setae.

Pronotum markedly heart-shaped, constricted basally (WP:WH=44:37; WP:LP=44:41; WP:WB=44:29), with very narrow side border and with distinct impressions.

Elytra 2.2 times as long as pronotum (WE:LE=28:92), at base smooth, gradually widened to apex, apical margin of each elytron rounded and apical margins of elytra together forming triangular cut at suture. Shoulders reduced, not prominent. Epipleuron long, broad, reaching apex of elytron. Wings reduced.

Abdomen with 6 visible sternites, tapering to apex.

Male. Protarsal segments 1–4 widened. Aedeagus ( Figs. 8–9 ) with median lobe large basally and pointed apically; internal sac feebly sclerotised; parameres blade-like, apex with three short setae each.

Female. Female genitalia as in Fig. 10 . Tergite X broad, rounded, and without setae. First gonocoxites widely separated and small. Second gonocoxites large, approximate, and with several short setae apically. Styli small and bearing two apical setae each. Spermatheca small, sclerotised.

Comparison. Lesteva dabanensis is in many characters similar to L. sajanensis , L. brathinoides and L. barguzinica . However, compared to L. sajanensis , in L. dabanensis the ocelli are strongly reduced (ocelli can be observed at high magnification only after the beetles have been cleared in 10% KOH and placed in glycerine), the elytra are more feebly rounded at the humeral angle; the aedeagus is shorter, with the base of the median lobe more enlarged, the apex narrower, and the parameres shorter. From L. brathinoides , whose distribution is confined to the East Sayan, L. dabanensis can be at once separated by darker coloration, longer elytra, strongly reduced ocelli, by the presence of pointed apex of the median lobe of the aedeagus. L. dabanensis is distinguished from L. barguzinica by paler coloration, longer elytra and by the shape of the aedeagus.

Remarks. Total or partial reduction of the ocelli has been known among Omaliinae ( Zerche 1990, 1992), particularly in many high altitude species, for example, in Hygrodromicus Tronquet, 1981 and in many species of the tribe Coryphiini.

Etymology. The specific epithet has been derived from the second part (Daban) of the name of the type locality: Khamar-Daban [= Hamar-Daban] mountain range.

Figures

FIGURE 10. Female genitalia of Lesteva dabanensis sp. n., ventral view. Scale bar 0.3 mm.

FIGURES 1 – 4. Habitus of Lesteva. 1 — L. dabanensis sp. n.; 2 — L. barguzinica sp. n.; 3 — L. sajanensis Zerche; 4 — L. brathinoides Zerche. Scale bar 1.3 mm.

FIGURES 5 – 7. Mouthparts of Lesteva dabanensis sp. n. 5 — right mandible, dorsal view; 6 — right maxilla, dorsal view; 7 — labrum, dorsal view. Scale bar 0.3 mm.

FIGURES 8 – 9. Aedeagus of Lesteva dabanensis sp. n. 8 — ventral view; 9 — lateral view. Scale bar 0.3 mm.