Stenichnini, Ganglbauer, 1899

Jałoszyński, Paweł, 2020, Himaloconnus Franz and Nogunius gen. n. of Japan (Coleoptera: Staphylinidae Scydmaeninae), Zootaxa 4822 (3), pp. 334-360 : 350-351

Key to Japanese genera of Stenichnini

1. Antennomeres X and XI demarcated by indistinct septum, antennae appear 10-segmented. [Ryukyus].................................................................................................... Syndicus Motschulsky

- Antennomere X and XI distinctly separated................................................................. 2

2. Sides of pronotum in at least posterior 1/3 developed as more or less sharp edges................................... 3

- Sides of pronotum lacking edges. ......................................................................... 5

3. Basal elytral foveae filled with dense setae; pronotum with antebasal transverse impression interrupted at middle by short longitudinal wrinkle. [Hokkaido].......................................................... Neuraphes Thomson

- Basal elytral foveae asetose; pronotum with complete transverse impression or with posteromedian tubercle and two pairs of antebasal pits........................................................................................ 4

4. Pronotum with complete transverse antebasal impression; mesoventral intercoxal process not reaching posterior margins of mesocoxae and with distinct posterior tip; aedeagus with parameres. [Shikoku, Honshu, Hokkaido; presumably also Kyushu]................................................................................... Scydmoraphes Reitter

- Pronotum with posteromedian tubercle and two pairs of antebasal pits; mesoventral intercoxal process reaching posterior margins of mesocoxae where it is fused with metaventrite; aedeagus lacking parameres. [Shikoku] ..... Rutaraphes Jałoszyński

5. Antenna with sharply delimited club composed of antennomeres X and XI. [Rykyus, Shikoku, Izu Is.] .................................................................................................... Nogunius Jałoszyński

- Antennae either gradually thickened or with club composed of a different number of antennomeres.................... 6

6. Each supraantennal tubercle with a pit near posteromesal margin; pronotal base with three distinct pits connected by transverse groove; mesoventral intercoxal process densely covered with short erect bristles. [Ryukyus].... Horaeomorphus Schaufuss

- Supraantennal tubercles lacking pits; pronotal base with a different number of pits (or none), or lacking transverse groove; mesoventral intercoxal process asetose or sparsely covered with thin setae........................................ 7

7. Each elytron with two basal foveae. ....................................................................... 8

- Each elytron with one basal fovea. ........................................................................ 9

8. Ventral surface of head with large U-shaped impression behind mentum; metaventral intercoxal process with a pair of spines adjacent at middle; prosternum laterally fused with hypomera; antennal club always trimerous and pronotum always broadest shortly in front of base. [Ryukyus] ....................................................... Himaloconnus Franz

- Ventral surface of head lacking U-shaped impression; metaventral intercoxal process lacking pair of spines; prosternum not fused with hypomera, with distinct notosternal sutures; antennae and pronotal shape variable. [all Japan]................................................................................................... Euconnus Thomson

9. Antennae gradually thickened, lacking delimited club; pronotum bell-shaped, broadest clearly in front of middle. [all Japan]................................................................................... Stenichnus Thomson

- Antennae with trimerous club; pronotum round, broadest near middle. [Rykyus, Shikoku; presumably all Japan] ............................................................................... Microscydmus Saulcy & Croissandeau