Scaphoxium opertum, Löbl, 2021

Löbl, Ivan, 2021, On the Bornean species of Scaphoxium LÖBL, 1979 (Coleoptera, Staphylinidae, Scaphidiinae), Linzer biologische Beiträge 53 (1), pp. 85-89 : 87

Scaphoxium opertum nov.sp. (Figs 3-5)

M a t e r i a l e x a m i n e d: Holotype: ♂, [E Malaysia] 10 miles point from Keningau Sabah, Is. Borneo 7.iii.1993 T. Ueno leg. ( MHNG).

D e s c r i p t i o n: Length 1.80 mm, width 1.0 mm, dorsoventral diameter 1.08 mm. Head and most of body dark brown, apical abdominal segments much lighter, femora and tibiae slightly lighter than thorax, tarsi and antennae yellowish. Length/width rations of antennomeres as: III 15/7: IV 19/8: V 30/8: VI 28/9: VII 45/13: VIII 35/11: IX 43/13: X 42/15: XI 58/15. Pronotal punctation very fine, hardly visible at 25 times magnification. Scutellum concealed. Elytral punctation distinct, punctures not well delimited, fine and dense, clearly visible at 20 times magnification, sutural striae parallel, shortened, starting about 0.20 mm posterior of level of pronotal lobe. Adsutural areas flat. Hypomeron very finely punctate, with short stria delimiting inferior vertical surface. Mesoventrite not microsculptured, impunctate, with low mesal ridge delimited by shallow impressions. Mesocoxal process of mesoventrite notched. Metaventrite not microsculptured, very finely and sparsely punctate, slightly convex in middle. Submesocoxal lines convex, punctate only along outer section. Submesocoxal areas 0.05 mm long, about as halves of shortest intervals to metacoxae. Metanepisternum flat, parallel-sided, with straight, narrow, shortened, and punctate suture. Abdomen very finely and sparsely punctate, dense basal puncture rows in middle of lateral margins of ventrites I excepted. Ventrites I to IV lacking microsculpture, apical abdominal segments with punctulate microsculpture.

Male characters: Segments I to III of protarsi hardly widened. Aedeagus (Figs 3-5) 0.86 mm long. Parameres narrow, each with subapical, mesally oriented, acute denticle. Proximal part of internal sac longitudinally striate. Middle of internal sac with two short, incurved sclerites surrounded by finely denticulate membranes and followed by two sclerites pointed apically and two narrow apical pieces.

C o m m e n t s: The aedeagal characters suggest relationship of this new species to S. grande LÖBL, 1986 . Notable are the very similar parameres having each a narrow subapical denticles pointed mesally. The structures of the internal sacs are, however, significantly distinctive in these two species, in particular by the presence of a pair of sclerotized subapical teeth and two narrow, apical sclerites present in S. opertum , absent from S. grande . Only S. simulans (LÖBL, 1971) 1986 possesses narrow and acute subapical parameral denticles. It is readily distinguished by its significantly smaller body (1.3 mm long) and the internal sac lacking teeth-like sclerites.

E t y m o l o g y: The species epithet is a Latin adjective meaning secrete, mysterious.