Elytrobium scindens, Assing, 2013

Assing, Volker, 2013, Two new genera of Lathrobiina from the East Palaearctic region (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 63 (2), pp. 219-239 : 228

Elytrobium scindens sp. n.

( Figs 30-42 , Map 1 )

Type material:

Holotype : “ CHINA: border Shaanxi-Sichuan [today border Shaanxi-Chongqing ], Daba Shan , pass 20 km SSE Zhenping / 1700-1800 m, 31°44'N, 109°35'E, 9.VII.2001 A. Smetana [C96a] / Holotypus  Elytrobium scindens sp. n., det. V. Assing 2013” (cAss). Paratype : “ CHINA (W-Hubei) Daba Shan, pass E Mt. Da Shennongjia, 12 km NW Muyuping, 31°30'N, 110°21'E, 1950 m (dry creek vall., mix. decid. forest) 16.-22.VII.2001 Wrase [13]” (cSch).

Etymology:

The specific epithet is the present participle of the Latin verb scindere (to scratch) and refers to the distinctly hook-shaped apex of the ventral process of the aedeagus.

Description:

Small species; body length 5.5-6.5 mm; length of forebody 3.0- 3.1 mm. Habitus as in Fig. 30 . Coloration: head blackish; pronotum blackish-brown; elytra and abdomen dark brown; legs with the femora dark-brown, the tibiae reddish-brown, and the tarsi yellowish-brown; antennae yellowish-red, with antennomere I slightly darker.

Head ( Fig. 31 ) 1.10-1.13 times as long as broad, broadest at posterior margin of eyes; lateral margins not converging directly behind eyes, but smoothly curving towards neck in dorsal view; posterior angles indistinct; frons transversely impressed and with pronounced microsculpture; punctation coarse and dense, sparser in median dorsal portion; interstices narrower than diameter of punctures (except in median dorsal portion), with very distinct microreticulation and subdued shine. Ventral aspect of head as in Fig. 32 . Eyes moderately large and composed of numerous fine ommatidia, approximately half as long as postocular region from posterior margin of eye to neck in dorsal view. Antenna 1.4 mm long; antennomeres IV-X approximately as long as broad. Maxillary palpi with palpomere III distinctly dilated apicad, somewhat flattened (i.e., oval in cross-section), approximately 2.5 times as long as broad. Other mouthparts as in Figs 40-42 .

Pronotum ( Fig. 31 ) 1.20-1.23 times as long as broad and 1.12-1.13 times as broad as head, moderately convex in cross-section, broadest slightly behind middle; lateral margins weakly convex in dorsal view, nearly straight; punctation similar to that of head; interstices with distinct microreticulation; impunctate median band very narrow.

Elytra ( Fig. 31 ) moderately long, approximately as long as pronotum; punctation dense, as coarse as that of pronotum, weakly defined to defined, irregular, not seriate; interstices without microreticulation, glossy. Hind wings fully developed. Protarsomeres I-IV strongly dilated. Metatarsomere I approximately as long as II.

Abdomen slightly narrower than elytra, segments III-VI of subequal width; punctation not very dense and moderately coarse on anterior tergites, gradually becoming finer and sparser towards the abdominal apex; interstices with shallow microreticulation; posterior margin of tergite VII with palisade fringe.

: sternite VII ( Fig. 33 ) distinctly transverse, 1.45 times as broad as long, and with very weakly concave posterior margin, pubescence unmodified; sternite VIII ( Fig. 34 ) weakly oblong, posterior excision very shallow and not angled in the middle, pubescence unmodified; sternite IX symmetric and apically moderately acute ( Fig. 35 ); aedeagus ( Figs 36-37 ) 0.65 mm long, ventral process abruptly bent subapically and apically distinctly hooked in lateral view.

: sternite VIII ( Fig. 38 ) 1.1 times as long as broad and with distinctly convex posterior margin; tergites IX-X as in Fig. 39 .

Comparative notes:

Elytrobium scindens differs from the similarly small E. seminitidum particularly by the presence of microsculpture on the pronotum, the transversely impressed frons, the slightly shorter elytra with non-seriate punctation, the less coarse and less dense punctation of the abdomen, the much more transverse male sternite VII, the much shallower posterior excision of the male sternite VIII, and by the differently shaped aedeagus. From the other species (re-)described above it is readily distinguished by smaller body size alone.

Distribution and natural history:

The species is known from two localities in the Daba Shan, one at the border between Chongqing and southern Shaanxi, and one in western Hubei ( Map 1 ). The holotype was sifted from moist to wet moss, fallen leaves and other debris around a small seepage in a secondary deciduous forest (SMETANA pers. comm.), the paratype was collected in a mixed deciduous forest. The altitudes range from approximately 1750 to 1950 m .

Figures

Map 1: Distribution of Elytrobium gen. n. in the southeastern East Palaearctic region: E. gongganum sp. n. (open circle); E. qinlinganum sp. n. (open triangle); E. scindens sp. n. (filled diamonds); E. seminitidum sp. n. (open diamond); E. alesianum sp. n. (filled circles); E. monilicorne (SHARP) (filled triangle).

Figs 30-44: Elytrobium scindens sp. n. (30-42) and Lathrobium elongatum (LINNAEUS) (43-44): habitus (30); forebody (31); median portion of ventral aspect of head (32); male sternite VII (33); male sternite VIII (34); male sternite IX (35); aedeagus in lateral and in ventral view (36-37); female sternite VIII (38); female tergites IX-X (39); right mandible (40); labrum (41, 43); labium (42, 44). Scale bars: 30-31: 1.0 mm; 33-34, 38-39: 0.5 mm; 32, 35-37, 40: 0.2 mm; 41-44: 0.1 mm.