Pseudobironium rapax, Löbl, 2022

Löbl, Ivan, 2022, Supplement to the knowledge of Scaphisomatini of Sabah, Malaysia (Coleoptera: Staphylinidae: Scaphidiinae), Acta Musei Moraviae, Scientiae biologicae 107 (1 - 2), pp. 7-19 : 14-15

Pseudobironium rapax sp. nov.

( Figs 8 ̅10)

Type material. Holotype male, Malaysia, Sabah, Crocker Range, Mawar Waterfall env. 17.VI.1996, 9c, vegetation debris and forest floor litter accumulated along large fallen trees near river ( MHNG) .

Description. Length 1.95 mm, width 1.30 mm. Head and most of body dark reddishbrown, apex of abdomen lighter, yellowish; femora and tibiae roughly as body, tarsi and antennae light brown. Maxillary palpi with palpomere IV narrow, tapering, about 4 times as long as wide. Length ratio of antennomeres as follows: III 15: IV 22: V 26: VI 21: VII 26: VIII 26: IX 27: X: 26: XI 35; antennomere XI about 3.5 times as long as wide. Pronotal punctation very fine, similar to that on frons, with punctures very shallow and not well delimited; middle of pronotal disc with puncture intervals about 4 to 10 times larger than puncture diameters. Elytra lacking lateral impressions, not flattened or impressed apically, lacking humps; discal punctation similar to pronotal. Hypomera impunctate, impressed posteriad. Mesoventrite lacking mesal ridge and lacking distinct setiferous punctures. Mesanepisternum very finely punctate, lacking microsculpture. Metaventrite lacking microsculpture; median area nearly flat, lacking impressions and tubercle, with two irregular rows of distinct admesal punctures. Lateral parts of metaventrite very finely and sparsely punctate. Metacoxal process impunctate, horizontal. Submesocoxal area short, about as fourth shortest interval to metacoxa. Submesocoxal line finely punctate. Mesotibiae and metatibiae slightly bent, ventral spur of mesotibiae straight. Ventrite Ilacking microsculpture, with very fine and scattered punctures; following ventrites and exposed tergites with punctulate microsculpture.

Male. Aedeagus ( Figs 8 ̅10) 0.74 mm long. Median lobe with basal bulb shorter than apical process, the latter slightly inflexed, with sinuate ventral margin (lateral view), and blunt tip; apical part of median lobe lacking distinct valves. Parameres nearly evenly wide, bent in dorsal view, straight in lateral view. Internal sac with pair of strongly sclerotized denticles and mesal sclerite, lacking flagellum and lacking apical spinose structures.

Etymology. The species epithet is a Latin noun, referring to the canine­like denticles of the internal sac.

Differential diagnosis. The species is as P. irregulare less than 2 mm long and thus conspicuous by its small body­size. It may be easily distinguished from P. irregulare by the evenly very fine elytral punctation, the narrow submesocoxal areas and ventrite I lacking microsculpture. The aedeagal characters suggest relationship with members of the P. subovatum group (see LÖBL & TANG 2013), though the shape of the admesal sclerites of the internal sac is unique. The species falls in the key species to couplet 27, to P. schuhi Löbl & Tang, 2013 from which it differs notably by the parameres evenly narrow, except at their basis.

Remarks. The single available specimen has its forelegs broken, probably lost when collected.

Figures

Figs 8-13. 8-10 ̅ Pseudobironium rapax sp. nov.; 8, 9 ̅ Aedeagus in dorsal and lateral views, scale = 0.1 mm; 10 ̅ Internal sac in dorsal view, scale = 0.1 mm. 11-13 ̅ Scaphoxium sinuatum sp. nov.; 11 ̅ Aedeagus in dorsal view, scale = 0.1 mm; 12 ̅ Apical part of paramere, dorsal view, scale = 0.05 mm; 13 ̅ Internal sac in dorsal view, scale = 0.05 mm.