Pseudobironium irregulare, 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 : 11-14

Pseudobironium irregulare sp. nov.

( Figs 5 ̅7)

Type material. Holotype male, SABAH: Poring Hot Springs 600 m 9.V.1987 Burckhardt ̅ Löbl ( MHNG) ; Paratypes: 1 female, SABAH: Crocker Ra. 1350 m, km 60 Kota Kinabalu­Tambunan 17.V.1987 Burckhardt ̅ Löbl ; female, BORNEO SABAH Tamis, Hwy AI 10 km NW Kinabalu Park Entr . 1100 m 24.V.87 A. Smetana ; 1 female, SABAH: E Mt. Kinabalu 1150 m, rte Ranau­Kota Kinabalu 24.V.1987 Burckhardt ̅ Löbl (all in MHNG) .

Description. Length 1.78̅ 1.87 mm, width 1.20̅ 1.35 mm. Head and most of body dark reddish­brown, metaventrite somewhat darkened, apex of abdomen lighter, yellowish, femora and tibiae roughly as body, tarsi and antennae lighter, yellowish. Maxillary palpi with palpomere IV narrow, tapering, about 4 times as long as wide. Length ratio of antennomeres as follows: III 14: IV 25: V 25: VI 22: VII 26: VIII 26: IX 26: X: 26: XI 31; antennomere XI about 4 times as long as wide. Pronotal punctation about as fine as that on frons, with punctures very shallow and not well delimited; middle of pronotal disc with puncture intervals about 5 to 10 times larger than puncture diameters. Elytra lacking lateral impressions, not flattened or impressed apically, lacking humps; discal punctation on prevailing surface similar to pronotal punctation, conspicuous patch of rather coarse punctures present on anterolateral area. Puncture patch separated from lateral and basal margins by rather broad, very finely punctate areas. Lateral striae coarsely punctate. Hypomera impunctate, flattened along basal margin. Mesoventrite lacking mesal ridge, with distinct setiferous punctures at lateral margins of coxal process, setae long. Mesanepisternum very finely punctate, lacking microsculpture. Metaventrite with inconspicuous striate to punctulate microsculpture; median area nearly flat, lacking impressions and lacking tubercle, its punctation fine, arranged to form two sparse admesal rows joined posteriorly. Lateral parts of metaventrite very finely and sparsely punctate. Metacoxal process impunctate, inflexed. Submesocoxal area slightly shorter than half of shortest interval to metacoxa. Submesocoxal line coarsely punctate. Mesotibiae and metatibiae slightly bent, ventral spur of mesotibiae straight. Exposed ventrites and tergites with distinct punctulate microsculpture, setiferous punctures very fine and scattered.

Male. Protarsus shorter than protibia, protarsomeres Ito III hardly widened, narrower than apex of tibiae, bearing short setae. Aedeagus ( Figs 5 ̅7) 0.68 mm long, weakly sclerotized. Median lobe with basal bulb shorter than apical process, the latter hardly inflexed, with sinuate ventral margin (lateral view) and blunt tip; apical part of median lobe overlapped by two valves. Parameres widened basally, weakly bent. Internal sac lacking sclerotized pieces, without distinct flagellum, bearing apical spinose structures.

Etymology. The species epithet is a Latin adjective meaning "irregulaȑ, referring to the elytral punctation.

Differential diagnosis. This species may be readily distinguished from its congeners, P. impressipenne Löbl, 1973 and P. subglabrum Löbl, 1990 excepted, by elytra bearing each an anterolateral patch of coarse punctures. In addition, its small body­size and the structure of the internal sac are diagnostic. It may be readily distinguished from P. impressipenne and P. subglabrum by the parameres widened basally. It falls to the couplet 25 in the key to the species in LÖBL & TANG (2013), to P. feai Pic , though the latter species is 2.90̅ 3.20 mm long and has a black body. The aedeagal characters suggest relationships with members of the P. plagiferum group. It may be distinguished from the three species placed in that group ( P. javanum Löbl & Tang, 2013 , P. plagiferum Löbl, 1980 , and P. spinipes Löbl & Tang, 2013 ) by the shape of the parameres and apex of the median lobe.

Figures

Figs 1-7. 1-4 ̅ Baeocera hutan sp. nov.; 1, 2 ̅ Aedeagus in dorsal and lateral views, scale = 0.2 mm; 3, 4 ̅ Internal sac in dorsal and lateral views, scale = 0.1 mm. 5-7 ̅ Pseudobironium irregulare sp. nov.; 5, 6 ̅ Aedeagus in dorsal and lateral views, scale = 0.1 mm; 7 ̅ Internal sac in dorsal view, scale = 0.1 mm.