Pseudobironium stewarti, Lobl & Liang Tang, 2013

Löbl, Ivan & Tang, Liang, 2013, A review of the genus Pseudobironium Pic (Coleoptera: Staphylinidae: Scaphidiinae), Revue suisse de Zoologie 120 (4), pp. 665-734 : 713-715

Pseudobironium stewarti sp. nov. Figs 72-74

HOLOTYPE: Ƌ, VIETNAM, Tuyen Quang Prov., 300m, Na Hang Reserve , 16-20.V.1997, rainforest FIT 97-8, leg. S. Peck ( MHNG).

DESCRIPTION: Length 2.65 mm, width 1.80 mm. Head, most of pronotum, most of anterior halves of elytra, mesoventrite and metaventrite very dark brown. Lateral parts of pronotum, prohypomera, lateral parts of elytra posterior humeral area, and abdomen somewhat lighter. Apical halves of elytra much lighter than elytral centres. Maxillary palpi, antennae and tarsi light brown, femora and tibiae dark brown. Maxillary palpi with palpomere IV tapering, about 4 times as long as wide. Length ratio of antennomeres as II 10: III 7: IV 12: V 15: VI 10: VII 16: VIII 15: IX 16: X 16: XI 20; antennomere XI about 3.3 times as long as wide. Head and pronotum with similar, fine and dense punctation. Punctures fairly well delimited, intervals between them mostly about as to three times as large as puncture diameters. Elytra lacking subapical humps and lateral impressions. Elytral punctation distinctly coarser that pronotal punctation, punctures well delimited, puncture intervals mostly about as large as, to twice large as puncture diameters. Prohypomera very finely punctate, appearing smooth. Mesoventrite with median ridge, coarsely punctate near margin. Metaventrite in middle almost flat, coarsely punctate except on narrow smooth mesal area, with strigulate microsculpture. Lateral parts of metaventrite very finely punctate, with strigulate microsculpture on posterior half, lacking microsculpture on anterior half. Submesocoxal area as long as third of shortest interval to metacoxa. Metacoxal process impunctate, microsculptured, without median stria or ridge, truncate. Mesotibiae and metatibiae weakly curved, mesotibial ventral spur straight. Abdominal sternite 1 very finely punctate, with long, oblique lateral impressions, and strigulate microsculpture. Following sternites with strigulate microsculpture, lacking basal wrinkles, very finely punctate.

FIGS 71-75

(71) Pseudobironium sparsepunctatum (Pic) , aedeagus in lateral view; scale bar = 0.2 mm. (72-74) Pseudobironium stewarti sp. nov., aedeagus in dorsal (72) and lateral (73) views, internal sac in dorsal view (74). (75) Pseudobironium ussuricum Löbl , apex of aedeagus with extruded internal sac; scale bars for aedeagus = 0.2 mm, for internal sac = 0.1 mm.

Male: Protibia longer than protarsus, latter not particularly elongate, with tarsomeres 1 to 3 weakly widened, much narrower than apex of protibia, bearing short tenent setae. Aedeagus (Figs 72-74) 0.79 mm long, moderately sclerotized. Basal bulb small. Apical process slightly longer than basal bulb, not inflexed, with ventral side sinuate, tip somewhat prominent ventrally and rounded in lateral view. Parameres narrow, almost evenly wide, arcuate in lateral view, straight with weakly bent apical parts in dorsal view, narrowly membranous along most of apical halves of the inner margins. Membranous parts of internal sac with short spicules posterior and below complex of sclerotized pieces.

DISTRIBUTION: Vietnam.

ETYMOLOGY: The species is named in honour of its collector, Stewart B. Peck,

Ottawa, Canada, one of the most efficient field workers the senior author ever met.

COMMENTS: This species resembles P. bicolor by its colour pattern, body size and elytral punctation. It differs however in having much finer pronotal punctation, different length ratio of the antennomeres, in particular by the antennomere XI much longer than III, the microsculptured lateroposterior parts of the metaventrite and entire surface of the 1st abdominal sternite. The aedeagal characters of P. stewarti suggest close relationships to P. horaki and P. bicolor from which it differs by the parameres conspicuously arcuate in lateral view and lacking apical lobes.