Stenus eumerus, Kiesenwetter, 1850

Puthz, V., 2014, Nordamerikanische Arten der Stenus eumerus-Gruppe (Coleoptera, Staphylinidae) 338. Beitrag zur Kenntnis der Steninen, Linzer biologische Beiträge 46 (2), pp. 1647-1669 : 1659-1660

Key to the North American species of the Stenus eumerus group

1 Elytral punctation very dense but without rugae.................................................................2

- Elytral punctation very dense and at parts rugose...............................................................5

2 Punctation of abdominal tergites coarser and denser (figs 4, 20, 24, 37, 39, 51, 63, 65)....3

- Punctation of abdominal tergites less coarse and less dense (figs 8, 13, 72).......................4

3: E (fig. 30.) In average slightly smaller (FB  1.46mm [1.35-1.6mm])........................... ........................................................................................................... blaisdellianus nov.sp. U.S.A.: WA?, OR, CA, NV?, CO?

-: E (figs 27-29). In average slightly larger (FB  1.53mm [1.4-1.6mm]) ......................... ...................................................................................................................... fenyesi nov.sp. U.S.A.: OR, CA

4: E (fig. 16). In average slightly larger (FB  1.4mm [1.3-1.5mm]) ................................. ............................................................................................................... californicus CASEY Canada: BC.- U.S.A.: OR, CA

-: E (fig. 17). In average slightly smaller (FB  1.32mm [1.30-1.35mm])......................... .................................................................................................................. wickhami nov.sp. U.S.A.: CA

5 Abdominal segment 6 with a very narrow threadlike lateral margination, at least in posterior half (figs 7, 8).......................................................................................................6

- Abdominal segment 6 without a threadlike lateral margination (figs 5, 6).........................8

6 In average smaller, FB  1.39mm. Punctation of metasternum coarser and denser (fig. 47, 48), interstices smooth.: Metatibiae with preapical spines, FB 1.24-1.5mm,  1.39mm. E (fig. 53-58)................................................ some specimens of tahoensis CASEY

- In average larger, FB  1.49-1.5mm. Punctation of metasternum less coarse and less dense, interstices ± distinctly reticulate.: Metatibae without a preapical spine...............7

7 Punctation of abdominal tergites coarser and denser (fig. 79), abdominal segments 3-6 with a complete treadlike lateral margination. FB 1.35-1.6mm,  1.49mm.: E (fig.3) .... ............................................................................................................... schuhianus nov.sp. U.S.A.: OR, WY, CA

- Punctation of abdominal tergites less coarse and less dense (fig. 72), abdominal segments 3-6 with a threadlike lateral margination only in posterior half. FB: 1.45- 1.6mm,  1. 53mm: Metatibiae without preapical spines, E (fig. 74) ............ bidens nov.sp. U.S.A.: CA

8 In average smaller, FB  1.4mm........................................................................................9

- In average larger, FB : 1.5mm.......................................................................................11

9 Ventral punctation of abdomen fine and sparse (fig. 38). FB:  1.4mm.: E (figs 27-29)............................................................................................................ vestalis CASEY U.S.A. : OR (?), CA, AZ?

- Ventral punctation of abdomen coarser and denser (exception: specimens of S. tahoensis)..........................................................................................................................10

10 Punctation of abdominal tergites slightly less dense, interstices slightly shiny.: Metatibiae with prepacial spines, FB 1.24-1.5mm,  1.39mm. E (figs 53-58) .................... ................................................................................................................... tahoensis CASEY Canada: BC.- U.S.A.: WA, ID, OR, NV, CA, CO

- Punctation of abdominal tergites slightly denser, interstices deeply reticulate, slightly matt. FB: 1.35-1.5mm,  1.44mm.: Metatibiae without preapical spines, E (fig. 62)...... .................................................................................................................... aurigans PUTHZ U.S.A. : TX, OK, KS. Mexico: Nueva Leon

11 Ventral punctation of abdomen coarse and dense (fig. 5). FB: 1.3-1.75mm,  1.54mm.: Metatibiae without preapical spines. E (fig. 75) .............................................................. ................................................................................................................... nimbosus CASEY U.S.A. : CO, AZ, NM?.- Mexico: Nueva Leon

- Ventral punctation of abdomen less coarse and less dense (fig. 66). FB: 1.5-1.6mm.: Metatibiae with preapical spines. E (fig. 69) ..................................... leechianus nov.sp. U.S.A.: CA.