Scaphidium coerulescens, Löbl, 2023

Löbl, Ivan, 2023, On a new Scaphidiini (Coleoptera: Staphylinidae: Scaphidiinae), Scaphidium coerulescens sp. nov., from New Guinea, Acta Musei Moraviae, Scientiae biologicae 108 (1 - 2), pp. 39-42 : 40-41

Scaphidium coerulescens sp. nov.

( Figs 1, 2 )

Type material. Holotype male, INDONESIA, Papua, Star Mountains , ABMISIBIL , 1950­ 2200 m, 4°38̕S, 140°30̕E, 29.i.­9.ii.2005, leg. T. Lackner / ZMA.INS. 5117729 ( NBCL). Paratypes, 3 males, 4 females, with same data as the holotype ( NBCL, MHNG); 1 male, INDONESIA, Papua, Kecamalan Nipsan WALMAK 1800 m 4°07̕S ̅ 139°36̕E 18­25.ii.2005, 1750­ 2250 m leg. T. Lackner ( NBCL).

Description. Length 3.90­4.10 mm. Head, body, femora, and tibiae blackish with blue or green metallic shine, antennae and tarsi black. Head width at posterior margins of eyes 1.03­1.22 mm, frons at narrowest point between eyes 0.13­0.15 mm wide. Frons at narrowest point between eyes 0.13­0.15 mm wide (about a third of eye width in dorsal view), with punctation irregularly scattered and fine, becoming dense posterior on the level of hind eye margins. Length/width ration of antennomere, in dorsal view: I 20/8: II 14/7: III 11/5: IV 15/5: V 12/6: VI 10/7: VII 15/15: VIII 13/21: IX 15/25: X 14/28: XI 23/27 (holotype). Pronotum 2.23­2.30 mm long, at base 2.60­2.67 mm wide, at anterior margin 1.47­150 mm wide; disc not raised above level of elytra, lateral margins sinuate; lateral margin striae coarsely and sparsely punctate, punctures smaller than puncture intervals; anterior margin stria densely and finely punctate; antebasal puncture row weakly impressed, interrupted in middle, consisting of coarse, not or hardly elongate punctures about as large or smaller than puncture intervals; discal punctation fine and rather sparse, punctures well delimited, puncture intervals about two to five times as large as puncture diameters. Scutellum slightly convex, its exposed part as long as wide at base. Elytra along suture 2.36­2.40 mm long, at longest point 2.80­3.10 mm, combined 2.75­2.92 mm wide; lateral contours evenly rounded, lateral margin carina exposed in dorsal view, lateral margin stria finely punctate; entire apical margin crenulate; sutural striae with punctures somewhat coarser than discal punctures; adsutural areas flat except near apex, widest in middle, narrowing anteriad and apicad; basal stria impressed with round punctures becoming gradually larger laterad; discal punctation similar to discal punctation of pronotum. Exposed tergites very finely punctate, with punctulate microsculpture. Hypomera, mesanepisterna and lateral parts of metaventrite smooth. Prosternum with low, triangular mesal ridge and dense row of coarse punctures along anterior margin. Pseudepimeron narrowly impressed along entire anterior and inner margins, and along inner half of posterior margin, with small triangular impression near inner margin, deep impression on level of anterior margin of metanepisternum. Mesoventrite with mesal ridge appears to be gradually raising anteriad due to lateral areas impressed gradually. Metaventrite with discrimen entire, apical margin uneven, hardly notched in middle, and oblique antecoxal striae. Metanepisterna with fine elongate stria and impressed, furrow­like suture. Metatibiae weakly curved, similar to mesotibiae, Ventrites very finely punctate.

Male. Profemur with anterior side flattened. Protibia slightly shorter than profemur, straight in basal third, curved and gradually thickened apicad posterior of basal third, near apex nearly three times as wide as near base, with small, elongate apical tubercle on inner side. Protarsus nearly as long as half of protibia, with tarsomeres I to III widened and bearing tenent setae. Mesotibia about 1.4 times as long as protibia and 1.6 times as long as mesotarsus, slightly curved and slightly thickened apicad, Mesotarsomeres I to III with ventral setae yellowish, much longer than protasal setae. Metaventrite with puncture patch very dense, covering posterior third of mesal area; setae raising from apical and apicolateral margins of patch yellowish, long and curled. Aedeagus ( Figs 1, 2 ) 1.36 mm long.

Female. Profemur with rounded inner side. Protibia about as long as four fifth of profemur, nearly straight, slightly thickening apicad, near apex about 1.5 times as wide as near base, lacking tubercle. Protarsus as long as half of protibia. Mesotibia about 1.5 times as long as protibia and 1.8 times as long as mesotarsus, evenly, weakly curved and slightly thickened apicad. Entire metaventrite very finely punctate, lacking obvious pubescence.

Etymology. The species epithet is a Latin adjective meaning dark bluish.

Differential diagnosis. This new species is similar to the Papuan S. coerulans Löbl, 1978 by the shape of the body, the colour pattern, and the punctation. It may be readily distinguished from the latter species by the crenulate apical margins of the elytra, the smooth hypomera, the mesal ridge of the mesoventrite not raised at its anterior end, and the genital characters. Notable among the secondary genital characters is the setose patch extending over the apical third of the metaventrite, with lateral setae conspicuously long. The aedeagi of these two species are also different. Unlike to S. coerulans , the apical margin of the median lobe is concealed in dorsal view, the apicomesal sclerite of the internal sac is not expanded and T­like, two small crescent­like sclerites are present at each side of the apicomesal sclerite, and a pocket with spines oriented toward centre is present in S. coerulescens . The New Guinean S. viride Löbl, 1978 has also a spinose pocket in the proximal part of the internal sac, not noticed in its description. Thus, S. coerulescens shares a possible synapomorphy with S. viride . These two species share also smooth hypomera and the mesoventral ridge not raised at its anterior margin. Both S. coerulescens and S. viride may be easily distinguished by their colour pattern and the shape of the male tibia.

Figures

Figs 1-2. Scaphidium coerulescens sp. nov., aedeagus in dorsal and lateral views. Scale = 0.3 mm.