Scaphisoma acutum, Lobl, 2015

Löbl, Ivan, 2015, On the Scaphidiinae (Coleoptera: Staphylinidae) of the Lesser Sunda Islands, Revue suisse de Zoologie 122 (1), pp. 75-120 : 103-105

Scaphisoma acutum sp. nov.

Figs 82-84

Holotype: MHNG; ♂; Indonesia, Indo: Lombok Batu Koq (N of G. Rinjani) 500 m, sec.forest in gorge D. Agosti 12.03.1991.

Etymology: The species epithet is a Latin adjective, meaning pointed and referring to pointed sclerites of the internal sac.

Description: Length 1.22 mm, width 0.82 mm. Head and body dark reddish-brown, appendages light. Pronotum and elytra lacking microsculpture. Antennae long, length/width ratio of antennomeres as follows: III 12/6: IV 28/5: V 40/6: VI 35/7: VII 38/11: VIII 37/8: IX 42/12 (left antennomeres X and XI, and right antennomere VIII-XI broken off). Antennomere III subtriangular. Pronotum finely punctate, punctures on basomedian area larger than near lateral and apical margins, lateral margins evenly rounded, lateral margin carinae visible in dorsal view. Point of scutellum exposed. Elytra with lateral margin carinae visible 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 deep, converging apically, somewhat curved at base, not extending laterad pronotal lobe, adsutural areas flat. Elytral punctation coarse and dense, punctures fairly well delimited, puncture intervals mostly about as large to twice as large as puncture diameters. Hypomera smooth. Mesepimeron about twice as interval to mesocoxa, about 5 times as long as wide. Metaventrite not microsculptured, lacking mesal impressions or sulci, punctation even, very fine and sparse. Submesocoxal areas 0.05 mm, almost as long as half of interval to metacoxa, submesocoxal lines convex, with fine marginal punctures. Metanepisternum flat, impressed below margin of metaventrite, slightly narrowed anteriad, with inner margin weakly sinuate. Tibiae straight. Abdomen very finely punctate. Sternite 1 with strigulate microsculpture distinct in middle, becoming punctulate or obsolete laterally, with not well delimited lateral impression. Submetacoxal areas 0.05 mm, submetacoxal lines convex, with fine margin punctures.

Male: Protarsal segments 1 to 3 hardly widened. Aedeagus (Figs 82-84) 0.37 mm long, weakly sclerotized, symmetrical. Median lobe with basal bulb much longer than apical process, lacking prominent articular process. Apical process strongly inflexed and narrowed apically, concealed in dorsal view. Parameres wide in basal halves and lobed, bent in middle, narrow in apical halves in dorsal view, gradually narrowed apically in lateral view. Internal sac lacking robust sclerites, with short denticulate structures in proximal part, long, very narrow and acute denticles in apical part.

Distribution: Indonesia: Lombok.

Type locality: Lombok, Batu Koq (N of G. Rinjani) 500 m.

Comments: The aedeagal characters suggest relationships of S. acutum with S. sesaotense Löbl, 1986 and the Sumatran S. irregulare Löbl, 1975 . The new species may be distinguished from S. sesaotense by the much smaller aedeagus with short parameral lobes and internal sac lacking large bifid sclerite. Scaphisoma irregulare has distinctive elytral punctation, with punctures on middle of disc coarser and also much denser than near margins. Unlike in S. acutum and S. sesaotense , S. irregular has parameres finely tuberculate, the parameral lobes very narrow, and does not possess sclerotized pieces in the internal sac.