Bironium species

Löbl, Ivan, 2021, A review of the Bironium Csiki, 1909 (Coleoptera: Staphylinidae: Scaphidiinae) of New Guinea and the Moluccas, Acta Musei Moraviae 106 (2), pp. 227-248 : 228-229

Key to the Bironium species of New Guinea and adjacent islands

1 Pronotumochraceous, elytrablack...................................... B. bicolor sp. nov.

- Colour patter of pronotum and elytra different. ................................................ 2

2 Elytral disc with distinct, often impressed punctures rows. Lateral parts of metaventrite with conspicuous coarse punctures. ............................................. 3

- Elytral disc without puncture rows. Lateral parts of metaventrite very finely punctate. ............................................................................................................. 6

3 Elytra uniformly black. ..................................................................................... 4

- Elytra maculate. .................................................................. B. maculatum Löbl

4 Antennomere XI yellowish, much lighter than preceding antennomers. Mesoventrite lacking median ridge. ......................................... B. flavapex Löbl

- Antennomere XI about as light as antennomeres IX and X. Mesoventrite with or without median ridge. ................................................................................... 5

5 Most of elytral disc coarsely punctate. Metaventrite with coarse punctures scattered over prevailing anterior surface. ...................... B. punctatum sp. nov.

- Most of elytral disc very finely punctate, coarse elytral punctures arrange to form two rows. Sides of metaventrite with few coarse punctures near anterior margins. ......................................................................................... Bironium sp.

6 Elytra bicolorous. .............................................................................................. 7

- Elytra uniformly reddish­brown to black. ......................................................... 8

7 Pronotum ochraceous, or ochraceous along lateral and anterior margins and with large dark spot. Hypomera ochraceous. Elytral disc with punctation usually uneven, on small part of disc coarser than on prevailing discal surface. .............. ........................................................................................... B. longipes (Reitter)

- Pronotum and hypomere entirely black. Elytral disc with punctation entirely very fine, similar to pronotal punctation. ............................ B. ornatum sp. nov.

8 Elytral punctation to large part much coarser than pronotal punctation. .......... 9

- Elytra and pronotum with similar, very fine punctation. ................................. 10

9 Body black, 3.0 to 3.2 mm long. Mesoventrite with robust mesal ridge. Apical part of parameres delimited by notch. ................................... B. grande sp. nov.

- Body­length 2.20 to 2.35 mm. Mesoventrite with mesal ridge. Apical part of parameresnotdelimitedby notch...................................... B. striatum sp. nov.

10 Small species, body­length less than 1.8 mm. ..................... B. maindai sp. nov.

- Larger species, body­length exceeding 1.8 mm. ............................................. 11

11 Elytra with basal striae entire, joined to lateral striae. Mesoventrite usually with distinct mesal ridge. ........................................................................................ 12

- Elytra with basal striae interrupted at level of humeral areas, not joined to lateral striae. Mesoventrite with or without mesal ridge. ........................................... 15

12 Parameres each split to form long ventral lobe extended nearly to level of apex of dorsal lobe. ................................................................................ B. biroi (Pic)

- Parameres of not split. ..................................................................................... 13

13 Median lobe of aedeagus with two robust, prominent processes situated mesally, anterior bases of parameres. ................................................... B. taurus sp. nov.

- Median lobe of aedeagus without ventral processes. ...................................... 14

14 Middle part of parameres not expanded. Mesoventrite very finely striate. .......... ................................................................................................. B. basicolle (Pic)

- Middle part of parameres expanded to form large lobes. Mesoventrite lacking striae. ................................................................................... B. albertisi sp. nov.

15 Metanepisterna broad, about 0.06- 0.07 mm wide. Internal sac of aedeagus with roof­like shaped distal sclerites and pair of proximal angulate, narrow sclerites. ...................................................................................................... B. loksai Löbl

- Metanepisterna narrow, about 0.01- 0.02 mm wide. Internal sac of aedeagus withproximalnarrow, transverse rod...................................... B. glabrum Löbl

16 Mesoventrite lacking mesal ridge. Metanepisterna very narrow, to large part concealed. Parameres narrowed and strongly sclerotized apically...................... ............................................................................................. B. rufulum sp. nov.

- Mesoventrite with mesal ridge. Metanepisterna distinct, about 0.04- 0.05 mm wide. Parameres broad and weakly sclerotized apically. ........ B. riedeli sp. nov.