Othius auster, Assing, 2015

Assing, Volker, 2015, A revision of Othiini. XIX. Two new species of Othius, the first record of the genus from Vietnam, and additional records (Coleoptera: Staphylinidae: Staphylininae), Linzer biologische Beiträge 47 (2), pp. 1235-1250 : 1246-1248

Othius auster nov.sp. ( Figs 11-23 , Map 1 )

T y p e m a t e r i a l: Holotype 3: "N-Vietnam - pass 8 km NW Sa Pa , 22°21'10''N, 103°46'01''E, 2010 m, second. forest, 13.VIII.2013, V. Assing [7c+2] / Holotypus 3 Othius auster sp. n. det. V. Assing 2014" (cAss). Paratypes: 13: "N-Vietnam - pass 8 km NW Sa Pa, 22°21'10''N, 103°46'01''E, 2010 m, second. forest, 12.VIII.2013, V. Assing [7b+2]" (cAss) ; 13: same data, but leg. Wunderle (cWun) .

E t y m o l o g y: The specific epithet (Latin, adjective: southern) alludes to the fact that this species currently represents the southernmost record of the genus.

D e s c r i p t i o n: Measurements (mm) and ratios (range): HL: 1.98-2.14; HW: 1.71- 1.83; PW: 1.89-2.10; PL: 2.38-2.64; EL: 1.28-1.49; TiL: 1.86-2.01; TaL: 1.43-1.53; TL: 13.4-15.1; HL/HW: 1.16-1.17; HW/PW: 0.87-0.90; PL/PW: 1.25-1.27; EL/PL: 0.54- 0.58; TaL/TiL: 0.75-0.77.

Large species (see measurements). Habitus as in Fig. 11 . Coloration: body black, with the apex of the abdomen (segments IX-X; posterior portion of segment VIII) brown to dark-brown; legs with blackish-brown femora and reddish-brown tibiae and tarsi; antennae blackish-brown; maxillary palpi reddish-brown to dark-brown.

Head ( Fig. 12 ) conspicuously oblong (see ratio HL/HW), with subparallel lateral margins (dorsal view), and distinctly narrower than pronotum (see ratio HW/PW); anterior pair of frontal punctures distinct; dorsal surface in posterior half and in lateral portions with double punctation, i.e., with irregularly spaced coarse macropunctures and with moderately dense micropunctation; micropunctures present also, though more sparsely, in anterior half of dorsal surface; interstices with distinct fine microreticulation composed of short transverse meshes anteriorly and transverse striae posteriorly ( Fig. 13 ). Eyes ( Fig. 12 ) small and weakly convex, approximately one-fourth as long as postocular region in dorsal view.

Pronotum ( Fig. 14 ) distinctly oblong (see ratio PL/PW); discal punctation pattern distinctive: 1+2 discal punctures situated laterally, i.e., about halfway between middle of pronotum and lateral margin; posterior puncture situated practically in posterior angle, separated from margin by a distance of approximately its diameter ( Fig. 15 ); surface with fine and distinct microreticulation composed of short transverse meshes ( Fig. 16 ).

Elytra ( Fig. 17 ) short, little more than half as long as pronotum (see ratio EL/PL); punctures ( Fig. 18 ) moderately dense, large, but very shallow; interstices with distinct irregular microsculpture ( Fig. 18 ) rendering the surface nearly matt. Hind wings completely reduced.

Abdomen approximately as broad as elytra; punctation shallow, moderately dense on tergites III-VI, sparse on tergites VII-VIII; interstices with fine transverse microsculpture; posterior margin of tergite VII without palisade fringe.

3: protarsomeres I-IV strongly dilated ( Fig. 11 ); sternites V-VII unmodified; sternite VIII posteriorly shallowly impressed, posterior margin weakly concave; posterior processes of hemitergites IX apically acute, but without tooth-like processes, barely reaching posterior margin of tergite X; sternite IX ( Fig. 19 ) broad, anteriorly deeply bifid, posterior margin deeply excised, aedeagus ( Figs 20-21 ) 1.8-2.0 mm long; parameres apically weakly dilated, far from reaching apex of median lobe, each with 4 apical setae; internal sac with 6 sclerotized internal structures ( Fig. 22 ): a long (0.4 mm) and apically acute median basal structure, a shorter (0.33 mm) median apical structure with a hookshaped apex (pointing ventrad), and two pairs of slender and straight lateral structures (length: approximately 0.4 mm), the inner pair apically obliquely truncate.

♀: unknown.

C o m p a r a t i v e n o t e s: This distinctive species is characterized not only by the morphology of the median lobe (particularly the internal structures), but also by the combination of large body size, a strongly oblong head, double punctation of the head, the characteristic microsculpture and punctation of the elytra, reduced hind wings, and the absence of a palisade fringe at the posterior margin of tergite VII. It additionally differs from the geographically closest congener, O. lubricus , by the more oblong pronotum and the much deeper posterior excision of the male sternite IX.

D i s t r i b u t i o n a n d b i o n o m i c s: Thetypelocalityissituatedatapass 8 km to the northwest of Sa Pa. The discovery of O. auster is remarkable in that it represents the first record from Vietnam, the first record from the Oriental region, and the southernmost record of the genus as a whole ( Map 1 ). The previous record in this respect was held by Othius smetanai ASSING, 1999 from Peitawushan in Pingtung Hsien, southern Taiwan (approximately 22°37'N, 120°46'E).

The type specimens were sifted from deep leaf litter in a secondary deciduous forest at an altitude of 2010-2030 m ( Fig. 23 ).

Figures

Map 1: Distribution of Othius in the East Palaearctic region east of the Himalaya, based on examined records (all records pooled). White circle: type locality of Othius auster nov.sp.

Figs 11-18: Othius auster nov.sp.: (11) habitus; (12) head; (13) median portion of head; (14) pronotum; (15) postero-lateral portion of pronotum; (16) median portion of pronotum; (17) elytra; (18) postero-sutural portion of left elytron. Scale bars: 11-12, 14-15, 17: 1.0 mm; 13, 18: 0.5 mm; 16: 0.2 mm.

Figs 19-22: Othius auster nov.sp.: (19) male sternite IX; (20-21) aedeagus in lateral and in ventral view; (22) internal structures of aedeagus in ventral view. Scale bars: 19-21: 1.0 mm; 22: 0.5 mm.

Fig. 23: Type locality of Othius auster. Photo: Paul Wunderle.