Othius bihamatus, 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 : 1242-1246

Othius bihamatus nov.sp. ( Figs 1-10 )

T y p e m a t e r i a l: Holotype 3 [slightly teneral]: " Pakistan: Prov. Swāt: Umg. Kalām [35°31'N, 72°35'E], 25.-28.VIII.1979, 2200-3000 m, Heinz leg. / coll. Korge / Holotypus 3 Othius bihamatus sp. n. det. V. Assing 2014" ( MNHUB) . Paratypes: 2♀♀: " Pakistan ( Kāgān-Tal ), Umg. Naran [34°54'N, 73°38'E], 2400-2700 m, 22.-26.VII.1981, Heinz leg. / coll. Korge " ( MNHUB, cAss) ; 1♀: " Pakistan; Kāgān-Tal : Umg. Nārān, 2400-3200 m, 6.-8.VIII.1979, Heinz leg / coll. Korge " ( MNHUB) .

E t y m o l o g y: The specific epithet (Latin, adjective: with two hooks) alludes to the apically hook-shaped basal median and apical median internal structures of the aedeagus.

D e s c r i p t i o n: Measurements (mm) and ratios (holotype; paratypes, range): HL: 2.04; 1.62-1.74; HW: 1.92; 1.48-1.65; PW: 2.04; 1.69-1.80; PL: 2.41; 1.89-2.07; EL: 1.71; 1.40-1.59; TiL: 1.68; 1.37-1.53; TaL: 1.37; 1.01-1.19; TL: 13.4; 10.9-11.6; HL/HW: 1.06; 1.06-1.08; HW/PW: 0.94; 0.89-0.92; PL/PW: 1.18; 1.13-1.15; EL/PL: 0.71; 0.74-0.79; TaL/TiL: 0.82; 0.73-0.78.

Large species (see measurements). Coloration: body black, with the elytra bright reddish (holotype) to dark reddish-brown (paratypes); legs reddish-brown to blackish, with the tibial bases and the tarsi reddish; antennae blackish-brown.

Head ( Fig. 1 ) weakly widened posteriorly, oblong, and somewhat narrower than pronotum (see ratios HL/HW and HW/PW); anterior pair of frontal punctures distinct, with additional smaller punctures; posterior pair of frontal punctures absent; median dorsal portion impunctate, except for sparse micropunctation; lateral portions with coarse and rather dense punctation; integument with distinct transverse microsculpture. Eyes of moderate size, slightly less than half the length of postocular region in dorsal view.

Pronotum ( Fig. 1 ) oblong (see ratio PL/PW); discal punctation pattern similar to that of most other Eastern Palaearctic congeners; posterior discal puncture (i. e., puncture near posterior angle) separated from lateral margin by a distance of approximately its diameter ( Fig. 2 ); microsculpture finely transverse.

Elytra ( Fig. 1 ) shorter than pronotum (see ratio EL/PL); punctation rather sparse, shallow and fine ( Fig. 3 ); interstices with very dense micropunctation ( Fig. 3 ) rendering the surface matt. Hind wings present. Protarsomeres I-IV with pronounced sexual dimorphism.

Abdomen slightly narrower than elytra; punctation fine, rather dense on tergites III-VI, somewhat sparser on tergites VII-VIII; interstices with fine transverse microsculpture; posterior margin of tergite VII with palisade fringe.

3: protarsomeres I-IV strongly dilated ( Fig. 1 ); sternites V-VII unmodified; sternite VIII posteriorly shallowly impressed, posterior margin weakly concave; posterior processes of hemitergites IX short, apically without tooth-like processes, not reaching posterior margin of tergite X; sternite IX broad, anteriorly shallowly bifid, posterior margin bisinuate, postero-lateral angles without spine-like processes ( Fig. 4 ); aedeagus 1.6 mm long, ventral process of nearly triangular shape in ventral view ( Fig. 5 ); parameres apically weakly dilated, each with 4 apical setae ( Figs 5 ); internal sac ( Figs 6-9 ) with 4 sclerotized internal structures: a long asymmetric median basal structure with an asymmetrically hookshaped apex (pointing to the left in ventral view), a slightly longer median apical structure with a hook-shaped apex (pointing ventrad), and a pair of short, stout, straight, and apically acute lateral structures.

♀: protarsomeres I-IV dilated, but distinctly less so than in 3; tergite X ( Fig. 10 ) with weakly modified submarginal setae, these setae long, slightly stouter than the other setae of the tergal surface, and apically weakly curved.

I n t r a s p e c i f i c v a r i a t i o n: The holotype is distinguished from the three female paratypes by somewhat paler coloration, larger size (see measurements), and a broader head. The specimen is evidently slightly teneral, which explains the different coloration. In other external characters, the holotype and the paratypes are similar. Moreover, the type locality is separated from the locality where the paratypes were found by only some 120 km. Therefore, the observed differences are attributed to intra- rather than interspecific variation. However, males from the environs of Naran would be needed to confirm this hypothesis.

C o m p a r a t i v e n o t e s: Previously, the sole known representative of the genus in Pakistan (Karakorum: Haramosh; Azad Jammu & Kashmir) was O. sinuosus ASSING, 1998 . Othius bihamatus is evidently closely related to this species, as can be inferred particularly from the similarly modified elytra (with extremely dense micropunctation) and the bisinuate posterior margin of the male sternite IX. The new species differs from O. sinuosus by larger average size and by the number and shapes of the internal structures of the aedeagus. In O. sinuosus , the median apical structure is more slender, relatively longer, and apically not hooked, the basal median structure is apically not hooked, and there are two pairs of somewhat curved lateral structures. For a detailed description and illustrations of O. sinuosus see ASSING (1998).

D i s t r i b u t i o n a n d b i o n o m i c s: The type specimens were collected in two localities in North-West Frontier Province, North Pakistan, at altitudes between 2400 and 3200 m. The holotype is apparently somewhat teneral.

Figures

Figs 1-10: Othius bihamatus nov.sp.: (1) forebody; (2) pronotum in lateral view; (3) median portion of elytra; (4) male sternite IX; (5) aedeagus in ventral view (without extruded internal sac); (6) extruded internal sac with internal structures in ventral view; (7) apical internal structures in lateral view; (8) basal internal structure in ventral view; (9) basal internal structure in lateral view; (10) female tergites IX and X. Scale bars: 1-2: 1.0 mm; 3-10: 0.5 mm.