Scaphidium metafasciatum, Löbl, 2025

Löbl, Ivan, 2025, On the identity of Scaphidium grande, with resurrection of S. inimpressum and S. melanopus and description of two new species (Coleoptera: Staphylinidae: Scaphidiinae), Acta Entomologica Musei Nationalis Pragae 65 (1), pp. 15-20 : 18-19

Scaphidium metafasciatum sp. nov.

( Figs 4 , 9 )

Type material. HOLOTYPE: J, labelled:ʻTAIWAN: Yilan Co., Ayu Forest Trail, Yuanshan To., 6.V.2018, leg. F.S.Huʼ ( TARI) . PARATYPES: same data as holotype, 2JJ ( TARI, MHNG); ʻTAIWAN: Yilan Co., Fushan Botanical Garden,Yuanshan To., 8.V.2018, on bark, leg. F.S. Huʼ, 1♀ ( MHNG). Description. Body length 5.50–6.75 mm, width 4.60–5.60 mm. Body black, with brown abdominal apex. Antennae black, with apices of antennomeres II to VI dark brown and apical third of XI dark brown. Pro- and mesofemora entirely black, metafemora black with narrow reddish fasciae. Tibiae black. Tarsi dark brown. Frons flat between eyes, at narrowest point 0.30–0.34 mm wide; impunctate on small posterior area, punctation anterior to smooth area dense and fine, consisting of round, not confluent punctures, punctation posterior to smooth area coarser and very dense, partially confluent. Eyes large, eye width in dorsal view about 2 times as wide as frons at narrowest point.Vertex distinctly punctate, with strigulate microsculpture. Punctation on clypeus finer and sparser than on anterior part of frons. Pronotum raising above elytra, with lateral contours weakly sinuate, antebasal puncture row impressed, disc densely punctate, punctures round, smaller than puncture intervals; anterior margin weakly concave, anterior margin stria with puncture row interrupted in middle. Elytron with humeral hump hardly developed, disc in middle weakly convex, moderately inflexed and not impressed apicad; punctation fine on anterior third to half of disc and along lateral margin up to apical fourth, similar to pronotal punctation, becoming coarse and dense apicad, on most of apical half much coarser than on pronotum; two or three discal rows of slightly larger punctures rather inconspicuous, sometimes hardly distinct; basal stria gradually impressed laterad, with coarse puncture larger than punctures of pronotal antebasal row; sutural stria rather coarsely punctate, adsutural area entirely raised and roof-like. Prosternum lacking microsculpture, anterior and anterolateral margins of prosternum with coarse, almost confluent, not elongate punctures. Hypomeron, and mesanepisternum with very fine but distinct, scattered punctures. Mesanepisternum with anterior beads narrow, not widening laterad, ending near posterior margin. Lateral parts of metaventrite finely and sparsely punctate, lacking microsculpture. Median area of metaventrite impressed. Ventrites with dense, reticulate microsculpture. Ventrite I rather coarsely and densely punctate, with punctures about as large as coarser punctures on elytral disc. Ventrites II to IV with elongate basal striae evanescent on mesal areas, and with very fine, hardly visible punctation.

Male. Profemur with ventral side flattened, bearing three rows of tubercles. Protibia shorter than mesotibia and slightly shorter than profemur, arcuate in lateral view, in basal three quarters evenly thick, slightly widening apically, near apex about 1.1 times as broad as at base (lateral view), with underside bearing rows of tubercles; lacking apical ridge or denticle. Metaventral setal patch covering nearly entire mesal area of metaventrite, setae light brown, recumbent, moderately long. Aedeagus ( Figs 4 , 9 ) 2.05–2.16 mm long.

Differential diagnosis. The species may be easily distinguished from other members of the S. grande group by the metafemora only having a reddish fascia, while the mesofemora are entirely black. It may be also distinguished from S. grande by distinctly punctate hypomera, mesanepisterna and lateral parts of metaventrite, ventrite I rather coarsely and densely punctate, and the male protibia lacking apical or subapical denticle or ridge. The shape of the aedeagus, with the median lobe gradually narrowing from the level of the dorsal valves, the broadly truncate upper dorsal edge of the apex, the internal sac with a trapeziform median sclerite extended basolaterally by narrow branches, and the form of the paired subbasal sclerites are diagnostic. The shape of the aedeagus and the internal sac with two small oblique subbasal sclerites are similar with those of S. reni Tang & Li, 2010 , while the weakly sclerotized and nearly straight basolateral stripes in the internal sac of S. metafasciatum are distinctive.

Etymology. The species epithet is a Latin adjective meaning fasciate posteriorly.

Distribution. Taiwan.

Figures

Figs 1–5. Aedeagi in Scaphidium grande group. 1 – S. grande Gestro, 1879 (Rumah Tuan Village, Sarawak); 2 – S. inimpressum Pic, 1920 (Defulan Trail, Taiwan); 3 – S. melanopus Achard, 1924 (lectotype); 4 – S. metafasciatum sp. nov. (holotype); 5 – S. grandior sp. nov. (holotype). Scale = 0.5 mm.

Figs 6–11. Internal sac of median lobe in Scaphidium grande group. 6 – S. grande Gestro, 1879 (Rumah Tuan Village, Sarawak); 7 – S. inimpressum Pic, 1920 (Defulan Trail, Taiwan); 8 – S. melanopus Achard, 1924 (lectotype); 9 – S. metafasciatum sp. nov. (holotype); 10 – S. grandior sp. nov. (holotype); 11 – Scaphidium sp. (Huisun, Taiwan).