Staphylinidae

Key to species

The following key to the species of coastal Staphylinidae of Atlantic Canada is provided. It is modified and adapted from Newton et al. (2000), Downie and Arnett (1996), Smetana (1995), and Herman (1972, 1976, 1986) together with additional material.

1 Antennae inserted anterior to a line drawn between the anterior margins of the eyes...................................................................................................... 2

– Antennae inserted posterior to a line drawn between the anterior margins of the eyes.................................................................................................... 24

2(1) Head with deep conical foveae on the vertex (Pselaphinae)........................................................................................................... Brachygluta abdominalis

– Head without deep conical foveae on the vertex......................................... 3

3(2) Head with a pair of ocelli between the posterior margins of the eyes (Omaliinae).......................................................................... Micralymma marinum

– Head without ocelli................................................................................... 4

4(3) Abdomen with seven visible abdominal sterna (Oxytelinae)....................... 5

– Abdomen with six visible abdominal sterna................................................ 9

5(4) Labrum entire medially.............................................................................. 6

– Labrum divided medially........................................................................... 8

6(5) Basal third of lateral pronotal margin markedly sinuate.............................. 7

– Basal third of lateral pronotal margin straight or evenly curved to base....................................................................................................... Bledius basalis

7(6) Ratio of elytral length/pronotal length (at midline) 1.58-1.76; elytra brownish-black with sub-scutellar yellowish spot........................... Bledius opaculus

– Ratio of elytral length/pronotal length (at midline) 1.33-1.50; elytra yellowish with black sutural and basal stripes................................. Bledius neglectus

8(5) Epipleural ridge of elytron present only on apex............ Bledius mandibularis

– Epipleural ridge of elytron present along entire length............ Bledius politus

9(4) Head constricted behind eyes so as to form a distinct neck visible from above................................................................................................................ 10

– Head not constricted behind eyes, no neck visible (Tachyporinae)................................................................................................. Sepedophilus marshami

10(9) Inter-segmental membranes of abdomen with a distinct rectangular “brick wall” pattern; pronotum with large post-coxal process (Paederinae)............................................................................... Ochthephilum fracticorne

– Inter-segmental membranes of abdomen various (rounded or triangular patterns, or pattern indistinct) but never with a “brick wall” pattern; pronotum without postcoxal process (Staphylininae)................................................ 11

11(10) Strongly sclerotized plate (single, or divided medially into two contiguous sclerites) in front of prosternum present (Xantholinini)........................... 12

– Strongly sclerotized plate in front of prosternum absent........................... 13

12(11) Metatibia with apical and sub-apical ctenidia, the latter interrupted medially but extended proximally along outer margin of metatibia............................................................................................................... Gyrohypnus angustatus

– Metatibia with apical ctenidium only.............................. Xantholinus linearis

13(11) Disc of pronotum either densely punctate or glabrous; ligula notched (Staphylinina)................................................................................................ 14

– Disc of prontotum generally with two rows of punctures medially; ligula entire, rounded or slightly sinuate apically (Philonthina)......................... 15

14(13) Disc of pronotum glabrous; white pubescence on the anterior angles of the pronotum, across the medial part of the elytra, and on abdominal tergites four and five..................................................... Creophilus maxillosus villosus

– Disc of pronotum densely punctate; lacking white pubescence................................................................................................................ Tasgius ater

15(13) Largest lateral macrosetal puncture of pronotum separated from the lateral margin by at most little more than the width of the puncture.................. 16

– Largest lateral macrosetal puncture of pronotum separated from the lateral margin by at least three times the width of the puncture....... Cafius bistriatus

16(15) Protarsus with basal four tarsomeres more or less dilated, each tarsus bearing modified pale setae on ventral surface in addition to regular marginal setae......................................................................................................... 17

– Protarsus with basal four tarsomeres not dilated, each tarsus bearing only regular marginal setae........................................................ Gabrius astutoides

17(16) Dorsal rows on pronotum each with four punctures................................ 18

– Dorsal rows on pronotum each with five punctures or more.................... 23

18(17) Lateral margins of pronotum at least slightly sinuate posteriorly in front of basal margin............................................................................................. 19

– Lateral margins of pronotum evenly arcuate to parallel posteriorly in front of basal margin............................................................................................. 21

19(18) Posterior basal line on visible abdominal tergites two and three acutely extended posteriad at middle................................................. Philonthus politus

– Posterior basal line on visible abdominal tergites two and three not acutely extended posteriad at middle................................................................... 20

20(19) Small species (6.8-7.8 mm); eyes large; pronotum iridescent............................................................................................... Philonthus umbratilis (in part)

– Large species (8.7 – 13.6 mm); eyes moderately large, pronotum not iridescent.................................................................................... Philonthus furvus

21(17) First antennal article bicolored, dark with underside yellow................................................................................................................ Philonthus cognatus

– First antennal article unicolored, dark...................................................... 22

22(21) Surface of pronotum iridescent....................... Philonthus umbratilis (in part)

– Surface of pronotum not iridescent............................ Philonthus carbonarius

23(17) Dorsal rows on pronotum each with five punctures........... Philonthus varians

– Dorsal rows on pronotum each with six punctures......... Philonthus couleensis

24(1) Hind coxae separated, small; eyes bulbous covering side of head (Steninae)........................................................................................... Stenus erythropus

– Hind coxae contiguous, large; eyes various but not bulbous and covering side of head (Aleocharinae)............................................................................. 25

25(24) Tarsal formula 5-5-5; maxillary and labial palps each with an apical pseudosegment (Aleocharini).................................................... Aleochara litoralis

Tarsal formula otherwise; maxillary and labial palps without apical pseudosegments.............................................................................................. 26

26(25) Tarsal formula 4-4-4 (Hypocyphtini)....................................... Oligota parva

– Tarsal formula 4-5-5................................................................................ 27

27 (26) Pronotum broadest subapically, narrowed behind to a base not more than 3/4 of the maximal width of the pronotum (Falagriini).................................. 28

– Pronotal base more than 3/4 of the maximal width of the pronotum (Athetini)................................................................................................ 29

28(27) Scutellum bicarinate............................................................ Falagria dissecta

– Scutellum not bicarinate................................................... Myrmecopora vaga

29(27) Pronotal hypomeron not at all visible in lateral view................................ 30

Pronotal hypomeron narrowly to moderately visible in lateral view.......... 32

30(29) Body robust, narrowly oval; antennal articles 4-6 slightly elongate and 7-10 quadrate to slightly transverse................................................... Mocyta fungi

– Body fine, subparallel; antennal articles 4-6 quadrate to transverse and 7-10 moderately to strongly transverse............................................................. 31

31(30) Body glossy; abdominal tergites sparsely to moderately densely punctuate; tergite eight of both sexes with antecostal suture (basal line) subparallel to the base of the disc......................................................................... Acrotona avia

– Body moderately glossy, appearing somewhat opaque and velvety; abdominal tergites densely punctuate; tergite eight of both sexes with antecostal suture (basal line) arcuate and joining base of the disc before reaching its margin and then reaching downwards toward the apical margin of disc................................................................................................. Strigota ambigua

32(29) Pronotum with setae in midline directed anteriorly; pronotum with asperate punctation....................................................... Atheta (Datomicra) acadiensis

– Pronotum with all setae directed posteriorly or posterolaterally; pronotum without asperate punctation..................................................................... 33

33(32) Body opaque; pronotum at mid-length almost as broad as elytra at base; abdomen subparallel and distinctly narrower than elytra along its entire length; apical margin of male tergite 8 with 2 small lateral dents and shallow medial emargination pointed medially......................................... Atheta novaescotiae

– Body glossy; pronotum at mid-length distinctly narrower than elytra at base; abdomen with sides arcuate, broadest in mid-length and about as broad as elytra; apical margin of male tergite 8 truncate and without any dents.................................................................................... Atheta (Thinobaena) vestita