Silphidae

Key to Alberta Silphidae (including Agyrtidae) (by: R. B. Madge, 2006)

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Key to Subfamilies.

1. Elytra punctate-striate; always covering abdomen. Antennae covered with rather long
setae, sparse on basal segments, denser on apical segments. (Some genera found in
Alberta have a uniform vestiture of microsetae on more than three apical segments.)
Gular sutures widely separated. No intersegmental sclerite vehind procoxae. Size
generally small -- 4 to 7 mm ............................................................................. AGYRTINAE
1'. Elytra randomly punctate, sometimes costate, and sometimes tuberculate or
transversely wrinkled as well; usually obliquely or squarely truncate and not covering
abdomen. Antennae with a uniform vestiture of microsetae covering only apical three
segments. Gular sutures either confluent except for an anterior sliver (nicrophorines)
or approaching with each other medially in an hour-glass shape (silphines). With an
intersegmental sclerite behind procoxae. Size generally large -- 8 to 25 mm .................. 2

2. Head with a fronto-clypeal suture. Gular sutures narrowly separated anteriorly, then
united. Abdomen with tergum 5 bearing a pair of mid-longitudinal stridulatory files.
Elytra not costate ............................................................................ NICROPHORINAE Kirby
2'. Head without a fronto-clypeal suture. Gular sutures narrowly separated at middle,
widely separated both anteriorly and posteriorly. Abdomen without stridulatory files.
Elytra usually tricostate ........................................................................ SILPHINAE Latreille

Subfamily AGYRTINAE
Key to Genera and Species in Alberta

(Species links are to species pages in the Strickland Virtual Museum)

1. Clypeus nearly pentagonal, with posterior margin angulate at middle. Mandibles not
toothed. Antennae with apical segments (except last) with a circle of white scales within
a sharp apical ring ....................................................................
Ipelates latus (Motschulsky)
1'. Clypeus transversely rectangular, with posterior margin slightly curved. Mandibles
with preapical teeth. Antennae with apical segments with no apical ring with white
scales .................................................................................................................................... 2

2. Pronotum constricted at base, with a strong depression in each posterior corner and
at middle of base. Frons usually with 2 pale eyespots. Males: protarsi scarcely
widened; aedeagus with a single paramere ............................... Pteroloma nebrioides Brown
2'. Pronotum not constricted at base, without basal impressions. Frons without eyespots.
Males: protarsi strongly widened; aedeagus without parameres .........................................
............................................................................................... Apteroloma tenuicorne (LeConte)

Subfamily NICROPHORINAE
Key to Species of Nicrophorus in Alberta

(Species links are to species pages in the Strickland Virtual Museum)

1. Pronotum without an anterior transverse impression on disc; lateral margins
extremely narrow; basal margin with a bead ....................
Nicrophorus carolinus (Linnaeus)
1'. Pronotum with an anterior transverse impression, at least at sides of disc; lateral
margins not extremely narrow; basal margin without a bead .......................................... 2

2. Pronotum densely covered with long golden hairs, except for two small discal spots
(if hair abraded then dense punctation is visible). Elytra with epipleuron orange, with a
black wedge at base ............................................................... Nicrophorus tomentosus Weber
2'. Pronotum without long golden hairs, at most a few short hairs towards sides;
punctation not dense. Elytra with epipleuron variable but not orange with a black
basal wedge ......................................................................................................................... 3

3. Posterior lobe of metepimeron with many long golden hairs. Pronotum always
cordate, with narrow margins ............................................................................................ 4
3'. Posterior lobe of metepimeron with some brown hairs or entirely glabrous. Pronotum
rarely cordate ...................................................................................................................... 6

4. Procoxae with very long hairs on anterior face. Inner face of metatibiae with a dense
brush of brown hairs. Elytra with outer apical angle rounded, without a small tooth;
middle black band reaching dorsal ridge of epipleuron ................................................... 5
4'. Procoxae without very long hairs on anterior face. Inner face of metatibiae with only
sparse hairs. Elytra with a small tooth at outer apical angle; middle black band not
reaching dorsal ridge of epipleuron .................................. Nicrophorus marginatus Fabricius

5. Antennal club with basal segment black, apical 3 orange; segment 3 usually deeply
notched on outer margin. Elytra with epipleura entirely orange ........................................
....................................................................................................... Nicrophorus obscurus Kirby
5'. Antennal club entirely orange; segment 3 usually not deeply notched on outer
margin. Elytra with epipleura orange with a prebasal black spot .......................................
............................................................................................... Nicrophorus guttula Motschulsky

6. Metatibiae strongly curved. Elytra with anterior fascia extending forward onto
shoulder. Metatrochanters with accessory spine surpassing apex (next to femur) .............
........................................................................................................... Nicrophorus sayi Laporte
6'. Metatibiae straight. Elytra with anterior fascia not extending forward onto shoulder.
Metatrochanters with accessory spine not surpassing apex .............................................. 7

7. Pronotum with anterior margin broadly excavate (when viewed from directly above).
Elytra with a dimple at shoulder; microsculpture isodiametric; epipleura bicoloured,
orange and black. Antennal club entirely black ................................................................ 8
7'. Pronotum with anterior margin straight. Elytra without a dimple at shoulder;
microsculpture composed of transverse lines or meshes; epipleura unicoloured, either
orange or black. Antennal club with basal segment black, apical 3 orange .................... 9

8. Elytra with base of epipleura orange, with a prebasal black spot. Antennae with
middle two segments of club (9 and 10) with a well developed patch of long, white
microsetae forming a figure of eight across base on both upper and lower surfaces .........
.................................................................................................. Nicrophorus vespilloides Herbst
8'. Elytra with base of epipleura entirely black. Antennae with middle two segments of
club with no such patch of microsetae ........................... Nicrophorus defodiens Mannerheim

9. Elytra with epipleura entirely black; anterior fascia reduced to a lateral spot ................
................................................................................................. Nicrophorus pustulatus Herschel
9'. Elytra with epipleura entirely orange; anterior fascia well developed ....................... 10

10. Elytra with epipleura narrow, with dorsal ridge turned up posteriorly; shoulder with
short erect hairs from base back to dorsal ridge; middle black band evanescent at sides,
often not reaching dorsal ridge of epipleuron. Metasternum with a bald area on each
side behind mesocoxae. Males (moderate to large individuals only): metatrochanters
with accessory lobe sharply bent down into a short spine, like a barb on a fish hook .......
......................................................................................... Nicrophorus hybridus Hatch & Angell
10'. Elytra with epipleura broad, with dorsal ridge turned down posteriorly; shoulder
with short erect hairs only at very base; middle black band reaching dorsal ridge of
epipleuron. Metasternum with hair extending to mesocoxae, without a bald area. Males
(moderate to large individuals only): metatrochanters with accessory spine only slightly
bent over ........................................................................... Nicrophorus investigator Zetterstedt

Subfamily SILPHINAE
Key to Genera and Species in Alberta

(Species links are to species pages in the Strickland Virtual Museum)

1. Eyes large, interocular distance on underside of head equal to width of mentum.
Males (moderate to large individuals only): metafemora swollen. Elytra with a narrow,
pre-apical band of orange spots ......................................
Necrodes surinamensis (Fabricius)
1'. Eyes small, interocular distance on underside of head much greater than width of
mentum. Males: metafemora not swollen ........................................................................... 2

2. Head with a short row of longer, more erect hairs just behind eyes. Females: genitalia
with styli bearing terminal setae which extend along outer face ...................................... 3
2'. Head without a short row of longer, more erect hairs just behind eyes. Females:
genitalia with styli bearing terminal setae which do not extend along outer face ........... 4

3. Elytra with shoulders toothed; without ridges between costae. Metafemora on inner
face without carinae. Pronotum with margins orange ..........................................................
.......................................................................................... Oiceoptoma noveboracense (Forster)
3'. Elytra with shoulders rounded; with many strong ridges between costae. Metafemora
on inner face with 2 carinae. Pronotum entirely black ................. Heterosilpha ramosa (Say)

4. Antennae with segment 3 distinctly longer than 2. Antennae closer to eyes than to
labrum. Mesocoxae widely separated. Elytra flat. Females: genitalia with coxites curving
up and styli basal ................................................................................................................. 5
4'. Antennae with segment 3 not longer than 2. Antennae as close to labrum as to eyes.
Mesocoxae narrowly separated. Elytra curving down at apex. Females: genitalia with
coxites straight or curving down at apex ................................. Aclypea bituberosa (LeConte)

5. Elytra with strong tubercles between costae .................. Thanatophilus lapponicus (Herbst)
5'. Elytra without tubercles between costae .........................................................................6

6. Elytra lacking costae 1 and 2 except at apex. Abdomen with sterna 7 and 8 both
entirely orange ............................................................ Thanatophilus coloradensis (Wickham)
6'. Elytra with 3 full costae. Abdomen with sterna 7 and 8 not both entirely orange ...... 7

7. Elytra with outer costa ending at top of posterior callus. Lobe of prothoracic
hypomeron rounded, without an apical membrane. Elytra with apex sexually dimorphic,
more extended in males .................................................. Thanatophilus trituberculatus (Kirby)
7'. Elytra with outer costa extending beyond posterior callus. Lobe of prothoracic
hypomeron pointed and with an apical membrane. Elytra with apex not sexually
dimorphic ........................................................................ Thanatophilus sagax (Mannerheim)