The Cryptophagidae of Canada and the northern United States of America

CJAI 40 -- December 20, 2019
doi:10.3752/cjai.2019.40

Georges Pelletier & Christian Hébert

An Editorial Corrigendum has been published for this paper doi:10.3752/cjai.2019.40ed.

Family CRYPTOPHAGIDAE Kirby 1837
(Mostly from Leschen & Skelley (2002))

Description: Length 0.8 to 5.2 mm, mostly between 1.2 and 3.0 mm. Body robust, oval or elongate-oval, moderately flattened or convex, rarely round; body colour often reddish brown, dark brown with elytra yellowish brown, rarely entirely dark brown to black, usually with moderately long to short, erect to decumbent silky pubescence; glandular ducts present in various parts of the body, probably for the secretion of fluids that impermeabilize the body against the high humidity found in their secretive habitat. Head partially retracted into thorax, longer than wide, usually without antennal groove; eyes usually entire, finely faceted; ocelli absent; genae carinate and projecting ventrally between eye and mentum; clypeus usually subquadrate; mandible with well developed mola, incisor apex and prostheca; maxilla with brushlike galea and lacinia, probably for collecting spores; labium with mentum wider than long; maxillary palpi 3-segmented; labial palpi 2-segmented. Antennae moderately long, usually with a 3-segmented club.
Pronotum with distinct lateral carina (except in Hypocoprus); posterior margin usually narrower than anterior margin of elytra, often with depressions at the base; hypopleuron usually without antennal grooves; prosternal process well developed. Scutellum well developed and visible. Mesocoxal cavities closed laterally by metaventrite; metaventrite usually elongate. Legs moderately short and slender in most species; procoxae spherical and separate; trochanter about 25% length of femur; tibia usually with 2 apical spines; tarsi usually 5-5-5 or 5-5-4 in male Cryptophaginae.
Elytra usually completely covering the abdomen, without impressed striae; punctation confused, usually not forming distinct rows, (except underneath in many Atomaria species) and apex with double suture; epipleuron usually distinct in anterior half, never reaching the apex.
Abdomen with 5 freely articulate ventrites; first ventrite longer than the second ventrite; intercoxal process moderately broad. Male genitalia usually bilaterally symmetrical in most species.
Habitat. Most species live in concealed wet habitats with decaying vegetation containing fungi. They are very common in leaf litter, humid soil and the bark of old trees on mold and fleshy fungi where they are microphagous, feeding on the mycelium, hyphae, conidia or spores. A few others are saprophagous. Many species, mostly introduced from Europe, can be found in stored food products, but feed only on mold. Some specialized species are usually collected in bird nests, ant nests and mammal burrows. Four species are found in the nests of bees and wasps. They are probably scavengers. Two species are associated with aquatic plants.
Seasonality. They emerge in the spring or summer and some adults can be active up to late fall. It is interesting to note that the Southeastern US species we found in Canada are more active between November and April. It shows that temperature and humidity are very important to stimulate the activity of those species. They are predominantly active during the evening and at night.
Collecting methods. Many species living in leaf litter can be collected in great numbers by sifting the litter and using a berlese or with light or pitfall traps. Those living in tree bark can be collected with a Lindgren funnel or with flight interception traps. A few species may be swept or beaten from the foliage. Other specialized species can be collected by hand. Rarely, a few species can be collected on carrion.
Similar species in other families often confused with Cryptophagidae
Most species often confused with Cryptophagidae belong to Erotylidae in the following small subfamilies (Figure 2):

• Cryptophilinae Toramini
  Toramus pulchellus (LeConte):Very similar to some Atomaria (Anchicera) but pronotum opaque with pair of depressions at base and elytra with pilosity minute and sparse.
  
• Cryptophilinae Cryptophilini
  Cryptophilus integer (Heer):Similar to few Atomaria but pronotum as wide as elytra at base with side borders visible throughout and two disconnected foveae at base.
  Cryptophilus seriatus Casey:Very similar to some Henoticus but pronotum widest slightly in front of middle with serrulation smaller and two disconnected foveae at base and elytra with punctation in dense rows.
  
• Loberinae
  Loberus species: Pronotum deeply impressed at basal middle and elytra with seven well-spaced rows of punctures.
  
• Cerylonidae Euxestinae
  Hypodacne punctata LeConte:Superficial similarity with Ephistemus and Tisactia but antennal club with antennomeres not loose and elytra without distinct pilosity.
  

Figure 2. Species in other families similar to Cryptophagidae.

Diagnoses and summaries for Cryptophaginae

Subfamily CRYPTOPHAGINAE
Frontoclypeal suture absent; pronotum with lateral carina present; meso-metaventral articulation with a double knob; tarsal formula 5-5-5 in female and 5-5-4 in male; male genitalia with speculum gastrale with long anterior strut, parameres mostly separate.

Tribe CRYPTOPHAGINI
Antennae remotely separate at base, inserted under sides of frons; labial palpi 2- segmented with basal palpomere subequal to apical palpomere; pronotum with lateral margin often serrate, dentate, with or without a callosity at anterior corners, without sublateral carinae and with distinct basal pits or grooves.

Antherophagus Dejean 1821
Pronotum with sides entire, without callosities at front corners and without lateral tooth at middle; head with a distinct clypeal notch in male. Widely distributed. Associated with flowers and bee or bumblebee nests. Fairly common. Four species in North America, all found in Canada.
Cryptophagus Herbst, 1792
Pronotum with distinct callosities at front corners and a distinct tooth near middle of sides; pilosity of elytra long, appressed, recurved or suberect. Widely distributed. Associated with forest leaf litter, rotting wood, also in food products stored in wet areas with high moisture, sometimes in ant nests or animal burrows. Very common. 38 species in North America, with 32 species in Canada, including 11 Nearctic, 7 Holarctic and 14 adventive, the majority of the latter group uncommon in natural habitats.

Henoticus Thomson, 1868
Body not dorsoventrally compressed; pronotum with sides distinctly serrate, without sublateral lines, serratures strong and recurved, with base deeply bifoveate, foveae connected by wide groove along basal margin; mesoventral process equal in width to mesocoxa; anterior lateral angle of metaventrite with a pubescent pit; elytra reddish to yellowish brown, rarely black, with sparse to moderately dense pubescence; legs with tarsomeres not strongly lobed beneath. Widely distributed. Associated with forest leaf litter, rotting wood, fungi and food products stored in wet areas with high moisture. Common. Four species in North America, all present in Canada, including two Nearctic, one Holarctic and one adventive.

Henotiderus Reitter, 1877
Body not dorsoventrally compressed; pronotum with sides distinctly serrate, with sublateral lines, serratures strong and recurved, with base deeply bifoveate, foveae not connected by wide groove along basal margin. Mostly transcontinental in Canada and northern US. Associated with fungi under bark of rotting wood. Fairly common. Two species in North America, both in Canada; one Nearctic and one Holarctic.

Micrambe Thomson, 1863
Pronotum sides with callosity covering anterior half (most Palearctic species have a shorter callosity covering anterior third or less), middle tooth lacking. One record in North America (in Quebec, Canada). Associated with Black Spruce trunk burned with fire. Rare. One species introduced from Europe: Micrambe ulicis. First record of the genus in North America.

Myrmedophila Bousquet, 1989
Pronotum with distinct callosities at front corners and a distinct tooth near middle of sides, sides with posterior half subparallel; pronotum and elytra with pilosity very short, appressed, setae shorter than distance between punctures. Transcontinental in Canada and northern US. Associated with ant nests of genus Formica. Uncommon. One native species in North America, occurring in Canada: Myrmedophila americana.

Pteryngium Reitter, 1887
Body dorsoventrally compressed; pronotum with sides distinctly serrate, without sublateral lines, serratures minute and not recurved, base with two small basal disconnected foveae; mesosternal process greater in width than mesocoxa; anterior lateral angle of metaventrite with a slight depression; elytra reddish to yellowish brown; legs with tarsomeres not strongly lobed beneath. In transcontinental Canada, Alaska and northern US. Associated mainly with conifer forests, sometimes in hardwood forests, in fungi and polypores. Uncommon. One Holarctic species in North America, in Canada: Pteryngium crenulatum.

Salebius Casey, 1900
Pronotum with smooth sides consisting of three distinct lobes. In western North America, from Alaska south to California. Associated with conifer forests, in trees under bark. Fairly common. Two species in North America, one occurring in Canada; one native and one Holarctic.

Telmatophilus Heer, 1841
Body entirely dark brown to black, densely clothed with silvery pubescence; pronotum with sides distinctly serrate, without sublateral lines, serratures minute and not recurved; legs with tarsomeres 2 and 3 strongly lobed beneath. In transcontinental Canada and northern US. Associated with aquatic plants of genera Spargania and Typha. Fairly common. Two species in North America, both in Canada; one native and one adventive.

Tribe CAENOSCELINI

Caenoscelis Thomson
Antennae closed together at base, inserted in frons; labial palpi 2-segmented, with basal palpomere wider than apical palpomere; pronotum with lateral margin smooth, with sublateral carinae, and without distinct basal pits or grooves; ventrite V of abdomen with modified setae. Widely distributed, but more common in transcontinental Canada, northern and western USA, extending south in the Appalachian Mountains. Very common. Mostly in forest leaf litter. Six species in North America, all found in Canada, including four natives and two Holarctic species.
Subfamily ATOMARIINAE
Frontoclypeal suture present; labial palpi 2-segmented with basal palpomere wider than apical palpomere; meso-metasternal articulation with lateral processes; tarsal formula 5-5-5 in both sexes; male genitalia broad, parameres fused.

Tribe HYPOCOPRIINI

Hypocoprus Motschulsky 1839
Pronotum nearly cylindrical, longer than wide, with lateral carina lacking; elytra very elongate, about 1.75x as long as wide, not covering the last tergite. In northwestern Canada. Associated with ant nests of genus Formica. Uncommon. One species in North America, found in Canada, Holarctic: Hypocoprus latridioides.

Tribe ATOMARIINI Le Conte
Pronotum with lateral carina present; elytra variable, usually 1.7x as long as wide or less, covering the last tergite. Glandular ducts present on various parts of the body.

Atomaria Stephens 1829
Head distinctly visible anterior to the pronotum. Pronotum usually widest from anterior 30 to 85% (except for 2 species). Elytra with sides forming a discontinuous line with the pronotum, distinctly punctate and hairy. Widely distributed. Associated with forest leaf litter, rotting wood, also in food products stored in wet areas with high moisture, sometimes in ant nests or animal burrows. Very common. 80 species in North America, with 75 species in Canada, including 52 Nearctic, 14 Holarctic and 14 adventive, many of the latter group being well established in natural habitats. To facilitate the understanding of this complex genus, all species were separated into different species groups, detailed as follows. This genus is divided into two major subgenera:

Subgenus Anchicera Thomson 1863
Elytra with sides arcuate throughout, usually about 1.35-1.5x as long as wide, often with uniform colouration (70% of the species), sometimes patterned (30%); antennae with A1 short and stout (95%), club with A9-A10 subquadrate (61%) or transverse (39%). Pronotum usually with a single side border (90% of the species), with sides distinctly converging posteriorly (84%) or subparallel (16%). Widely distributed. Very common. 35 species in North America, with 34 species in Canada, including 18 Nearctic, 8 Holarctic and 9 adventive. This subgenus can be divided into seven species groups:

1. Anchicera ornata sp. gr.: Pronotum with double-side borders along most of its length. In transcontinental Canada and northern US. Uncommon. Three species, all adventive.
   
2. Anchicera pusilla sp. gr.: Pronotum with sides distinctly converging posteriorly; antennal club with A9-A10 transverse. Widely distributed. Very common. Six species, with two newly described Nearctic, two Holarctic and two adventives.
   
3. Anchicera kamtschatica sp. gr.: Pronotum with sides distinctly converging posteriorly, with both side borders completely visible from dorsal view; antennal club with A9-A10 subquadrate. In transcontinental Canada and Alaska. Common. Four species, with three Nearctic including two newly described species and one Holarctic.
   
4. Anchicera atra sp. gr.: Pronotum with sides distinctly converging posteriorly, with both side borders visible within posterior 50% only from dorsal view; antennal club with A9 subquadrate, A10 subquadrate or transverse; elytra unicolor, without distinctive pattern. Widely distributed. Very common. Nine species, with six Nearctic including three newly described species, two Holarctic and one adventive.
   
5. Anchicera mesomela sp. gr.: Pronotum with sides distinctly converging posteriorly, with both side borders visible within posterior 50% only from dorsal view; antennal club with A9-A10 subquadrate; elytra bicolor, with distinctive pattern. Widely distributed. Very common. Five species, with three Nearctic, one Holarctic and one adventive.
   
6. Anchicera testacea sp. gr.: Pronotum with sides distinctly subparallel at posterior 0.5; antennal club with A9-A10 transverse. Widely distributed. Common. Five species, with one Nearctic, two Holarctic and two adventives.
   
7. Anchicera nubipennis sp. gr.: Pronotum with sides distinctly subparallel at posterior 0.5; antennal club with A9-A10 subquadrate. Mostly found in western North America. Uncommon. Three species, all Nearctic, including one newly described species.

Subgenus Atomaria Stephens 1829
Elytra with sides mostly straight, at least at basal 35%, slightly convergent at basal 35-60% to nearly parallel at basal 65%, usually with uniform colouration (91% of the species) and pubescence decumbent or appressed (88%); antennae with A1 elongated and recurved (70%) or short and stout (30%), club with A9-A10 usually transverse (71%) or subquadrate (29%); pronotum with sides distinctly converging posteriorly (84%) or subparallel (16%). Widely distributed. Very common. 45 species in North America, with 42 species in Canada, including 34 Nearctic, 6 Holarctic and 5 adventive. This subgenus can be divided into 10 species groups:

1. Atomaria fimetarii sp. gr.: Antennae with A11 distinctly narrower than A10; body cylindrical, very convex, pronotum stout, as broad as elytra. In transcontinental Canada and northern US. Uncommon. One Holarctic species: A. fimetarii.
   
2. Atomaria nigrirostris sp. gr.: Pronotum with sharply defined basal transverse groove restricted to middle third, sometimes extending to sides. Widely distributed. Mostly uncommon, except the very common A. nigrirostris. Many species specialized in animal burrows or nests. Six species: four Nearctic including two newly described species, one Holarctic and one adventive.
   
3. Atomaria umbrina sp. gr.: Antennae with A6-A10 strongly transverse. In transcontinental Canada. Uncommon. Two species, including one newly described Nearctic species and one adventive species: A. umbrina.
   
4. Atomaria puella sp. gr.: Elytra with pubescence sparse and suberected. In central and western North America; one species in southeastern US. Uncommon. Apparently specialized in ant nests. Three species, all Nearctic, including one newly described species in Georgia.
   
5. Atomaria linearis sp. gr.: Body elongate, pronotum subquadrate, about 1.15x as wide as long, elytra about 1.8x as long as wide. In western US. Rare. Pest species associated with sugar beets. One adventive species introduced into California: A. linearis.
   
6. Atomaria elongatula sp. gr.: Antennae with A1 short, about 1.3x as long as its apical width, and about 1.2-1.5x as long as A2. Mostly in transcontinental Canada, Alaska, northern and western US, extending south in the Appalachian Mountains. Fairly common. Mostly under the bark of trees, possibly many species specialized in bird nests. Nine species: with seven Nearctic including four newly described species, and two Holarctic.
   
7. Atomaria crassula sp. gr.: Antennae with A1 elongated and recurved, about 1.5x as long as its apical width and more than 1.5x as long as A2; club with A9-A10 subquadrate. Mostly in transcontinental Canada, Alaska, northern and western US. Fairly common. Mostly under bark of conifers trees. Three species, all Nearctic.
   
8. Atomaria vespertina sp. gr.: Antennae with A1 elongated and recurved, about 1.5x as long as its apical width and more than 1.5x as long as A2, club with A9 subquadrate to slightly transverse and A10 slightly to distinctly transverse. Mostly in transcontinental Canada, Alaska, northern and western US, extending south in the Appalachian Mountains. Uncommon, except the common A. lineola. Mostly under bark of conifer and hardwood trees. Five species: three Nearctic, including one newly described species, one Holarctic and one adventive.
   
9. Atomaria alpina sp. gr.: Antennae with A1 elongated and recurved, about 1.5x as long as its apical width and more than 1.5x as long as A2, club with A9-A10 distinctly transverse; pronotum with sides arcuate at anterior 50-70%, widest posterior to middle, not sinuate at middle. Mostly in transcontinental Canada, Alaska, northern and western US, extending south in the Appalachian Mountains. Uncommon. Mostly under bark of conifer and hardwood trees. Six species: five Nearctic, including two newly described species and one adventive.
   
10. Atomaria affinis sp. gr.: Antennae with A1 elongated and recurved, about 1.5x as long as its apical width, more than 1.5x as long as A2, club with A9-A10 distinctly transverse; pronotum with sides sinuate at middle. Mostly in transcontinental Canada, Alaska, northern and western US extending south in the Appalachian Mountains. Fairly common. Mostly under bark of trees of conifers and hardwood. Ten species: nine Nearctic, including two newly described species, and one Holarctic.

Curelius Stephens, 1829
Head mostly concealed under the pronotum; pronotum widest at base; elytra with sides forming a continuous line with the pronotum; body yellowish red, about 1.65-1.75x as long as wide, with punctuations small but distinct. In southeastern US, not yet recorded in Canada. In hardwood trees, mainly oak forests. Very common. One introduced species: Curelius japonicus.

Ephistemus Stephens, 1829
Head mostly concealed under the pronotum; pronotum widest at base; elytra with sides forming a continuous line with the pronotum; body reddish to dark brown or black, often paler apically, broadly oval, about 1.5-1.6x as long as wide, with punctation minute, almost indistinct. Widely distributed. Indoor or outdoor species, often associated with lawns, one species associated with cactus. Fairly common. One Nearctic species in southwestern US and one adventive species: Ephistemus globulus.

Tisactia Casey, 1900
Head mostly concealed under the pronotum; pronotum widest at base; elytra with sides forming a continuous line with the pronotum; body oblong-oval, about 1.8x as long as wide, with punctuations small but distinct. In southeastern Canada and eastern US. Rare. One Nearctic species: Tisactia subglabra.