Nazeris discissus, Assing, 2014

Assing, Volker, 2014, A revision of Nazeris. VI. On the fauna of East Yunnan, China (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (2), pp. 355-373 : 363-365

Nazeris discissus sp. n.

( Figs 26–31 , Map 2 )

Type material: Holotype ♂: “ CHINA [22a] – Yunnan, SE Pingbian, primary forest, 22°54'31"N, 103°41'44"E, 2100 m, 28.VIII.2014, V. Assing / Holotypus ♂ Nazeris discissus sp. n., det. V. Assing 2014” (cAss).

Paratypes: 3 ♂♂ [all teneral]: same data as holotype (cAss) ; 1 ♂, 1 ♀ [both teneral]: same data as holotype, but leg. M. Schülke (cSch) ; 1 ♂, 3 ♀♀ [all teneral]: “ CHINA [22] – Yunnan, SE Pingbian, primary forest, 22°54'31"N, 103°41'44"E, 2100 m, 27.VIII.2014, V. Assing” (cAss, MNHUB) .

Etymology: The specific epithet is the past participle of the Latin verb discindere (to cut apart) and alludes to the apically deeply divided ventral process of the aedeagus.

Description: Rather large species; body length 6.5–8.5 mm; length of forebody 3.8–4.1 mm. Coloration: body blackish; legs and antennae yellowish, with antennomeres I–III pale-redddish.

Head ( Fig. 26 ) weakly oblong, approximately 1.05 times as long as broad; lateral contours behind eyes smoothly and weakly curving towards posterior constriction in dorsal view, posterior angles obsolete; punctation very dense, not very coarse, and distinctly umbilicate; interstices forming narrow ridges, without microsculpture. Eyes less than one-third as long as distance from posterior margin of eye to posterior constriction in dorsal view. Antenna 2.2–2.4 mm long.

Pronotum ( Fig. 26 ) approximately 1.2 times as long as broad and 0.9 times as broad as head; punctation very dense and much coarser than that of head; midline posteriorly with short and narrow impunctate glossy elevation; postero-lateral portions with glossy callosities; interstices without microsculpture and glossy.

Elytra ( Fig. 26 ) 0.52–0.55 times as long as pronotum; humeral angles obsolete; punctation approximately as coarse and as dense as that of pronotum; interstices with- out microsculpture and glossy. Hind wings completely reduced. Metatarsomere I elongated, shorter than the combined length of II–V.

Abdomen 1.20–1.25 times as broad as elytra; punctation moderately coarse and conspicuously dense on tergites III–VI, nearly as dense on tergite VII, and somewhat sparser and finer on tergite VIII; tergites III–VI and anterior portion of tergite VII without, tergite VIII and posterior portion of tergite VII with very shallow microreticulation; posterior margin of tergite VII with narrow rudiment of a palisade fringe; posterior margin of tergite VIII strongly convex.

♂: sternite VII ( Fig. 27 ) approximately 1.5 times as broad as long, with shallow postero-median impression, this impression with short black setae, posterior margin with shallow median concavity, this concavity with a dense lateral cluster of long black setae on either side ( Fig. 28 ); sternite VIII ( Fig. 29 ) approximately as long as broad and with weakly convex anterior margin, posterior excision narrowly V-shaped, approximately one-third as deep as length of sternite; aedeagus ( Figs 30–31 ) approximately 1.7 mm long; ventral process very long, apico-ventrally deeply incised in the middle, apically of distinctive shape particularly in ventral view, basally with an obtusely angled projection on either side; dorso-lateral apophyses weakly sclerotized, very short, not reaching middle of ventral process, strongly dilated in apical half.

Comparative notes: Nazeris discissus , too, clearly belongs to the N. brevilobatus group. It shares the synapomorphies (modifications of the male sternite VII and the aedeagus) with other species of this group, but differs by larger body size, the shapes and chaetotaxy of the male sternites VII and VIII, and particularly by the morphology of the aedeagus (shapes of the ventral process and of the dorso-lateral apophyses).

Distribution and natural history: The type locality is situated in the Dawei Shan Virgin Forest Park near Pingbian, southeastern Yunnan ( Map 2 ). The specimens were sifted from leaf litter in a primary subtropical broadleaved forest at an altitude of 2100 m, together with N. semifissus and numerous other undescribed species of Staphylinidae . All the paratypes are more or less distinctly teneral.

Figures

Map 2: Distribution of the named species of Nazeris brevilobatus group in eastern Yunnan: N. brevilobatus sp. n. (white circle); N. virilis sp. n. (black circles); N. claviger sp. n. (black diamond); N. constrictus sp. n. (white triangles), N. discissus sp. n. (black square).

Figs 26–33: Nazeris discissus sp. n. (26–31), N. constrictus sp. n. (32), and N. claviger sp. n. (33): forebody (26); male sternite VII (27); postero-median portion of male sternite VII (28); male sternite VIII (29); aedeagus in lateral and in ventral view (30–31); median portion of aedeagus in ventral view (32–33). Scale bars: 26: 1.0 mm; 27, 29–31: 0.5 mm; 28, 32–33: 0.2 mm.