Scaphoxium sinuatum Löbl 2022, sp. nov

Scaphoxium sinuatum sp. nov. Figs 11 ̅13 Type material. Holotype male, Malaysia, Sabah, Batu Punggul Resort env., 24.VI. ̅ 1.VII.1996, 11c. vegetation debris and forest floor litter accumulated around large trees near river (MHNG). Description. Length 1.18 mm, width 0.55 mm, dorsoventral diameter 0.62 mm. Thorax, elytra and most of abdomen uniformly reddish­brown, head somewhat lighter, apical abdominal segments light, nearly yellowish, femora and tibiae roughly as thorax, tarsi lighter, antennae light brown. Length/width ratios of antennomeres as follows: III 22 /5: IV 17 /4: V 22 /4: VI 23 /4: VII 28 /7: VIII 20 /7: IX 28/11: X: 28/11: XI 38 /12. Pronotal and elytral punctation similar, very fine, hardly visible at 40 times magnification. Scutellum concealed. Elytra with sutural striae parallel, shortened, starting about 0.15 mm posterior of margin of pronotal lobe, adsutural areas hardly raised. Hypomeron with scattered, very fine punctured and short oblique stria. Mesoventrite with mesal impression shallow, narrowed posteriad, lacking mesal ridge and lacking microsculpture. Margin of mesocoxal process rounded. Metaventrite lacking microsculpture, very finely punctate, convex in middle. Lateral stria oblique, nearly reaching convex, finely punctate submesocoxal line. Submesocoxal area about 0.03 mm, as long as half of the shortest interval to margin of metacoxa. Metanepisternum flat, with suture fairly narrow, punctate, somewhat rounded. Abdomen very finely punctate, median areas of ventrites with punctulate microsculpture. Male. Segments Ito III of protarsi hardly widened. Aedeagus (Figs 11 ̅13) 0.44 mm long. Parameres narrowed posterior of basal section, gradually weakly widened toward narrow apical section, not forming subapical lobe or process; outer margins of parameres concave and inner margins strongly sclerotized posterior of narrowed apical section. Internal sac bearing two pairs of sclerotized pieces, outer larger and more sclerotized than inner pair, expanded apically, inner pair widened proximally, with margins becoming indistinct apically; scale­like, spine­like or filamentous structures absent. Etymology. The species epithet is a Latin adjective meaning "sinuatȅ, referring to the outer margins of the parameres. Differential diagnosis. The body­size of this new species is significantly smaller than that of other Bornean species and the shape of its parameres is diagnostic for it. The new species is similar to S. bilobum Löbl, 2015 from Lombok. It shares with the latter the simple internal sac of the aedeagus lacking spine­like, denticulate or striate membranous structures in combination with the presence of two pairs of admesal sclerites. However, the outer pair of sclerites is much more expanded and the inner sclerites are much shorter and broader in S. sinuatum, which may be distinguished from B. bilobum also by its wide impression of the mesoventrite, finer punctation of the lateral parts of the metaventrite and shorter submesocoxal areas.
Published as part of Löbl, Ivan, 2022, Supplement to the knowledge of Scaphisomatini of Sabah, Malaysia (Coleoptera: Staphylinidae: Scaphidiinae), pp. 7-19 in Acta Musei Moraviae, Scientiae biologicae 107 (1 - 2) on pages 17-18, DOI: 10.5281/zenodo.7501705
{"references":["LOBL I. 2015: On the Scaphidiinae (Coleoptera: Staphylinidae) of the Lesser Sunda Islands. Revue suisse de zoologie 122 (1): 75 ‾ 120."]}