Scaphisoma aereum, Lobl, 2015

Löbl, Ivan, 2015, On the Scaphidiinae (Coleoptera: Staphylinidae) of the Lesser Sunda Islands, Revue suisse de Zoologie 122 (1), pp. 75-120 : 97

Scaphisoma aereum sp. nov.

Figs 68-69

Holotype: SMNS; ♂; Indonesia, W. Sumbawa Batudulang , 30 km S of Sumb. Besar, 1000 m Bolm lgt. 10. Febr. 1994.

Paratypes: SMNS, MHNG; 2 ♂; with the same data as the holotype.

Etymology: The species epithet is a Latin adjective, meaning sheathed.

Description: Length 1.70-1.75 mm, width 1.07-1.10 mm. Head and most of body uniformly blackish-brown to black, abdomen and femora reddish-brown, tibiae, antennae and tarsi lighter, almost yellowish. Pronotum and elytra lacking microsculpture, very finely punctate. Antennae long, length/width ratio of antennomeres as follows: III 12/7: IV 38/6: V 48/6: VI 45/7: VII 51/12: VIII 35/9: IX 53/13: X 40/15 (XI missing in all specimens). Antennomere III short, subtriangular. Lateral margins of pronotum evenly rounded, lateral margin carinae not visible in dorsal view. Point of scutellum exposed. Elytra with lateral margin carinae exposed in dorsal view, apical margins truncate, inner apical angle rounded, not prominent, situated posterior level of outer angles, sutural margin not raised, sutural striae fairly shallow, parallel, at base somewhat curved, not extending laterad pronotal lobe, adsutural areas flat. Elytral punctation sparse and very fine near base, becoming more dense and less fine apically, punctures distinctly larger than those on pronotum. Hypomera smooth. Mesepimera about as long as two thirds of interval to mesocoxa. Metaventrite not microsculptured, with median part flattened, conspicuous mesal groove and two foveiform apicomedian impressions. Submesocoxal areas 0.05 mm, about as long as fourth of interval to metacoxa, submesocoxal lines convex, with very fine marginal punctures. Metanepisternum flat, narrowed toward angles, with inner margin weekly rounded, impressed below margin of metaventrite. Tibiae straight. Abdomen with microsculpture consisting of transverse striae. Submetacoxal areas 0.07 mm, submetacoxal lines convex, with distinct margin punctures.

Male: Protarsal segments 1 to 3 hardly widened. Aedeagus (Figs 68-69) 0.38-0.41 mm long, fairly sclerotized. Median lobe asymmetrical, with small basal bulb, articular process robust, not prominent, apical process abruptly curved and narrowed in dorsal view, arcuate and tapering in lateral view, tip acute in dorsal and lateral views. Parameres somewhat asymmetrical, almost evenly wide, weakly arcuate in lateral view, sinuate in dorsal view, inner margins not membranous, pores scattered in basal halves. Internal sac with moderately sclerotized flagellum and very finely denticulate membranes.

Distribution: Indonesia: Sumbawa.

Type locality: W. Sumbawa, Batudulang, 30 km S of Sumb. Besar, 1000 m.

Comments: This species appears closely related with S. aequum . Both possess metaventrite with a median groove and a pair of foveiform impressions, and have similar aedeagi. These species may be easily distinguished by their colour pattern. In addition, the groove of the metaventrite is shorter, the elytral punctation finer, and the apical process of the median lobe is abruptly narrowed in S. aereum .