Agathidium depressum Fall

WHEELER, QUENTIN D. & MILLER, KELLY B., 2005, Slime-Mold Beetles Of The Genus Agathidium Panzer In North And Central America, Part I. Coleoptera: Leiodidae, Bulletin of the American Museum of Natural History 2005 (290), pp. 1-95 : 65-69

Agathidium depressum Fall Figures 96–99 , 119–121

Agathidium depressum Fall, 1934: 108 ; Hatch, 1957.

TYPE MATERIAL: Holotype, Ƌ in MCZC labeled ‘‘Terrace BC Mrs WW Hip pisley/ Ƌ/ TYPE depressum [‘TYPE’ underlined in red, ‘depressum’ handwritten]/ M.C.Z. Type 24035 [red label]/ H.C. FALL COLLEC­ TION / HOLOTYPE, Agathidium depressum

Fall, 1934 [red label with black line bor­ der]’’.

TYPE LOCALITY: Canada, British Columbia, Terrace.

DIAGNOSIS: Agathidium depressum can be separated from other species of the A. revolvens group by the following combination of characters: body elongate­oval, dorsoventrally flattened (figs. 96, 97); color dark reddishbrown; elytral punctation coarser, denser than pronotal punctation, with several poorly defined serial rows of punctures, series often comprised of an irregular double row of punctures; aedeagus with median lobe swollen subapically (fig. 120), operculum with deep, rounded emargination, each lobe of operculum with conspicuous, rounded terminal disk (fig. 121); and lateral lobes apically flattened, spatulate (figs. 119, 120).

DESCRIPTION: Body elongate oval, strongly dorsoventrally depressed, attenuate posteriorly, weakly contractile (figs. 96, 97); TBL = about 3.6 mm. Color dark reddish­brown; cranium with pale central spot, antenna reddish­brown, club slightly darker; pronotum paler than elytra, particularly and broadly around margins; elytra paler at apices and along narrow marginal band; venter dark reddish­brown, legs paler.

Head subquadrate, dorsoventrally flattened, wider than long (figs. 96, 97), OHW/ MDL = 1.3; labrum small, transverse, emarginate medially, surface punctate with long, fine setae; frontoclypeal suture incomplete, lightly impressed basal arcuate line only, with no vestige of lateral portions of suture; surface shiny, with moderately dense, irregularly distributed punctures, area between punctures with irregularly distributed micropunctules; a single, shallow puncture larger than others of head located above each eye, posterior to middle of eye, just above supraocular carina; eye large, conspicuous, anterolateral, finely faceted; with short postocular temporum, gradually narrowed immediately behind eye, separated from frons by distinct supraocular carina running from lateral margin of clypeal region to posterior margin of cranium; antennomere III about as long as IV + V, ratio of length of II:III = 0.8:1; VII distinctly longer, but about same width as VIII, much smaller than IX, ratio of width VII:VIII:IX = 1.1:1:1.3; with abrupt 3­seg­ mented club. Pronotum broad, transversely oval, not strongly convex; with shallow posterior emargination medially; PNW/PNL = 1.7, PNL/PNH = 1.6; punctures smaller, less dense than those of head, irregularly distributed; area between punctures smooth, shiny, with sparse, irregularly distributed micropunctules. Elytra elongate, dorsoventrally compressed; ELW/SEL = 0.83; with coarser, denser punctation than pronotum; punctures larger than those of head; with several poorly defined serial rows of punctures, about a single puncture wide, blending with slightly smaller, irregularly distributed punctures between; smaller punctures sometimes nearly forming parallel series; surface between punctures smooth, shiny, with irregularly distributed, sparse micropunctules; sutural stria impressed in apical three­fourths; area between sutural striae elevated as slight rooflike median prominence; sutural stria confluent with suture shortly before apex; humeral angle broadly rounded. Mesosternum relatively large; anterior portion with longitudinal median carina, surface alutaceous, subdivided by oblique line. Metasternum with small, moderately dense, setose punctures; surface between densely, finely alutaceous.

Male tarsi 5–5–4; pro­ and mesobasotarsomeres enlarged, with spatulate setae beneath; left mandible without tusk; metafemur with apical posterior tooth, relatively small, broad, not well defined; metasternal fovea very small, anteromedial, transverse, with a few setae slightly longer than those of metasternal surface (fig. 98). Aedeagus elongate, median lobe with apex laterally minutely serrate, small, pointed, ventrally recurved (figs. 119, 120); apical pores dense, in double row (fig. 119); operculum broad at base, deeply bifurcate, emargination round­ ed, each lobe with distinct elevated oval apical area (figs. 120, 121), apices spatulate in lateral view (fig. 119); lateral lobe stout, elongate, apex laterally flattened, spatulate with setae nearly terminal (figs. 119, 120); endophallus with paired, large, heavily sclerotized spines.

Female tarsi 5–4–4.

DISTRIBUTION: Agathidium depressum was reported by Fall (1934) from British Columbia, Seward and McKinley Park, Alaska, Edmonton, Alberta, and Montreal and Rigaud, Quebec. Another specimen from Urbana, Illinois, was ‘‘doubtfully referred’’ to the species by Fall. We did not examine this specimen, but it may be better assigned to A. dubitans . Fall also assigned two specimens from California of the type series of A. revolvens in the LeConte collection to A. depressum . The species is the most broadly distributed of the species in this group (fig. 99).

SPECIMENS EXAMINED: CANADA: Alberta: Sibbold Flats Rec Area, 6 Sep 1981, FIT, RS Anderson (2, QDWC) ; Banff , 7 May 1930, O Bryant (1, CASC) ; Whitford L., 18 May 1924, O Bryant (3, CASC) ; Demmitt , 3 km W 90 km NW Grand Prairie, 12 Jun 1984, poplar forest, FIT, S and J Peck (1, PECK) ; 11 mi NE Robb, 4 Aug 1985, lodgepole pine forest, FIT, RS Anderson (1, CNCI) ; Edmonton , 21 Aug 1917, FS Carr, paratype (1, MCZC). British Columbia: Stanley, K Graham (1, CASC) ; Stanley , 15 Aug 1932, K Graham (2, CASC) ; Stanley, 1932, K Graham (1, CASC). Manitoba: The Pas , 28 May 1930, O Bryant (3, CASC). Quebec: Montreal, paratypes (2, MCZC) ; Duparquet , 3 Jun 1938, GS Smith (1, CASC) ; Rigaud, paratype (1, MCZC) ; Duparque , 26 Aug 1934, under Poplar bark, GS Smith (1, CASC) .

UNITED STATES: Alaska: McKinley Park , 8 Jul 1924, paratypes (2, MCZC) ; Pligrim Hot Springs nr Nome , 6 Aug 1995, on Stemonitus fusca, SL Stephenson (2, CUIC) ; Pligrim Hot Springs nr Nome , 6 Aug 1995, on Badhamia sp. , SL Stephenson (6, CUIC) ; Pligrim Hot Springs nr Nome , 6 Aug 1995, decaying log, SL Stephenson (1, CUIC) ; Seward, 15 Jun 1911, WS McAlpine, paratype (1, MCZC). California: Santa Barbara Mts , 21 Jul 1892, paratypes (2, MCZC) ; El Dorado Co.: 10 mi E Kyburz , 29 Jun 1975, Ponderosa pine duff, FG Andrews (4, CASC) ; Inyo Co.: Sierra Nevada Mts S Fk Lubkin Ck , 5 Apr 1982, 6300′, D Giuliani (1, CASC) ; Nevada Co.: Sagehen Creek nr Hobart Mills , 24 Jun 1964, SG Seminoff (1, CASC) ; Independence Lake , 13 Sep 1969, FG Andrews (1, CASC) ; San Bernadino Co.: 30 mi ENE Redlands, South Fk Campgroundd, Santa Ana River , 13 May 1981, 6300′, L Herman (1, AMNH) ; San Bernardino Co.: Lake Fulmore , Nov 1967, litter, Tullgren funnel, D Hagstrum (1, CASC) ; Snow Creek nr Forest Home, San Bern. Mts , 16 Jul 1961, in wash, EL Sleeper (1, CASC) ; Siskiyou Co.: Mt Shasta, 30 Oct 1969 (1, CASC). Colorado: Rabbit Ears Pass , 1 Jul 1953, 8000′, under stone, Bryant (1, CASC) ; Hinsdale Co.: Martin Ranch, Weminuche Valley , 14 Aug 1977, FG Andrews (1, CASC). Illinois: Urbana, 1 May 1921, CP Alexander, paratype (1, MCZC). Nevada: Eureka Co. : Monitor Range, 21 mi S 28 mi W Eureka, 1987–1988, 8000′, D Giuliani (1, CASC) ; Nye Co.: 5 mi N 10 mi E Currant, Currant Summit, 28 Mar 1987, 7000′, D Giuliani (1, CASC). Washington: Spokane Co. : Bald Knob Cmgr. Mt Spokane SP, 24 Jul 1978, 4800′, WJ Turner (5, WSUC) ; Whitman Co.: Lyle Grove 8 mi SW Pullman, 29 Mar 1973, under bark Pinus ponderosa, SD Berkenkamp (1, WSUC). Wyoming: Park Co. : Yellowstone Natl Park , Cub Creek , 2 Jul 1984, FG Andrews (1, CASC) .

DISCUSSION: Specimens from Alaska, Nome County, Pilgrim Hot Springs (CUIC), were collected from Stemonitis fusca and Badhamia sp. The species has been collected from a variety of litter sources including rotting logs and pine duff. Elevation records are from 4800 to 8000 ft.

Agathidium dubitans Fall

Figures 99 , 122–130

Agathidium dubitans Fall, 1934: 110 .

TYPE MATERIAL: Holotype, Ƌ in MCZC labeled ‘‘Ƌ/ TYPE dubitans [‘TYPE’ underlined in red, ‘dubitans’ handwritten]/ M.C.Z. Type 24036 [red label]/ H.C. FALL COL­ LECTION / Agathidium dubitans Fall [handwritten, with red line around label]/ HOLO­ TYPE, Agathidium dubitans Fall, 1934 [red label with black line border]’’.

TYPE LOCALITY: United States, New Mexico, Otero Co., Cloudcroft.

DIAGNOSIS: Agathidium dubitans can be separated from other species in this group by the following combination of characters: body elongate­oval, dorsoventrally flattened (figs. 126, 127); color reddish­brown; elytral punctation coarser and denser than pronotal punctation (figs. 123, 124), with several poorly defined serial rows of punctures, series generally comprised of a single row of punctures; aedeagus with median lobe in ventral aspect distinctly constricted subapically (fig. 129); operculum deeply emarginate, each lobe of operculum apically rounded (fig. 129); lateral lobes apically flattened, spatulate (figs. 128, 129); and endophallus with arms of median armature blunt and without prominent apicomedial tooth between apical arms (fig. 130).

DESCRIPTION: Body elongate oval, strongly dorsoventrally depressed, attenuate posteriorly, weakly contractile (figs. 126, 127); TBL = about 3.2 mm. Color reddish­brown; cranium with pale central spot, antenna testaceous, club reddish­brown; pronotum paler than elytra, yellowish­red; venter and tibiae reddish­brown, femora testaceous.

Head subquadrate, dorsoventrally flattened, wider than long (figs. 126, 127), OHW/MDL = 1.4; labrum small, transverse, emarginate medially, surface punctate with long, fine setae; frontoclypeal suture present, indistinct; dorsal surface shiny, with moderately dense, irregularly distributed small punctures (fig. 122); area between punctures with randomly distributed micropunctules; without large punctures behind frontoclypeal suture; eye large, conspicuous, anterolateral, finely faceted; with short postocular temporum, gradually narrowed immediately behind eye, separated from frons by distinct supraocular carina running from lateral margin of clypeal region to posterior margin of cranium; without a larger puncture above each eye; antennomere III longer than IV + V; ratio length II:III = 1:1.7; VII distinctly longer, slightly wider than VIII, much smaller than IX; ratio width VII:VIII:IX = 1.4:1:1.5; with abrupt 3­segmented club. Pronotum broad, transversely oval, not strongly convex; PNW/PNL = 1.9; PNL/PNH = 1.3; with very shallow posterior emargination medially; punctures smaller, slightly more dense than those of head, irregularly distributed (fig. 123); area between punctures smooth, shiny, with sparse, irregularly distributed micropunctules. Elytra broadly ovate, SEL/ELW = 1.1 with punctation coarser, but less dense than that of head or pronotum; punctures larger than those of head; with several poorly defined serial rows of punctures, more or less single puncture wide, blending with slightly smaller, irregularly distributed punctures between; smaller punctures sometimes nearly forming parallel series (fig. 124); surface between punctures smooth, shiny, with irregularly distributed, sparse micropunctules; sutural stria impressed in apical three­fourths; area between sutural striae elevated as slight median ‘‘carina’’; sutural stria confluent with suture before apex; humeral angle broadly rounded. Mesosternum relatively large; anterior portion with weak longitudinal median carina, surface alutaceous, subdivided by oblique line. Metasternum with small, moderately dense, setose punctures; surface between densely, finely alutaceous to imbricate.

Male tarsi 5–5–4; with pro­ and mesobasotarsomeres enlarged, with spatulate setae beneath; left mandible without tusk; metafemur with apical posterior tooth relatively small, broad, not well defined, more or less defined by apical angle of femur; metasternal fovea minute, punctiform, set in broad depression, anteromedial (fig. 125). Aedeagus elongate, narrow, ventrally curved; median lobe narrowed at apex, sharply ventrally curved, with lateral pectinate pattern of apical ducts, with minute serrations in lateral view (fig. 128); lateral lobes attain base of operculum, apices expanded, abruptly spatulate in lateral view, compressed in ventral view (fig. 129); operculum bifurcate, lobes bluntly rounded apically (fig. 129); endophallus with medial armature with apically, basolaterally, and basally directed arms which are short and bluntly rounded, without distinct, pointed tooth between apical arms or with short, rounded prominence only (fig. 130).

Female tarsi 5–4–4.

DISTRIBUTION: This species is known from Arizona, New Mexico, Ohio, Pennsylvania, and Tennessee. The seemingly disjunct distribution of this species from the southwestern United States and areas from Tennessee to Pennsylvania may indicate that the species is more widespread than current collection information indicates.

SPECIMENS EXAMINED: UNITED STATES: Arizona: 10 mi NW Flagstaff, San Franciso Mts , 18 Jul 1979, 9500′, spruce fir aspen meadow, malaise, S and J Peck (1, PECK) ; 10 mi W Greer Mt, Baldy, Ft Apache Indian Res. , 3 May 1979, R Baranowski (2, LUND) ; Pima Co.: Sta. Catalina Mts, Mt Lemmon , 5 Sep 1974, 9300′ (1, MCZC). Ohio: Champaign Co. : Cedar Bog, 4 mi SW Urbana (1, AMNH) ; Delaware Co.: colr. (1, AMNH). Pennsylvania: Jeannette , 16 Sep 2002 (2, CMNH) ; Pittsburgh, 24 Aug (1, CMNH). Tennessee: Gr. Smokey Mts, NP (1, AMNH) .

DISCUSSION: Elevation records are from 9300 to 9500 ft.

Figures

Fig. 96. Agathidium depressum Fall, habitus, dorsal.

Figs. 97, 98. Agathidium depressum Fall: 97, habitus, lateral; 98, male metasternal fovea.

Fig. 99. Geographic distribution of Agathidium revolvens group species: A. depressum Fall = •; A. dubitanoides, n.sp. = *; A. dubitans Fall = ·; A. jasperanum Fall = ^.

Figs. 119–121. Agathidium depressum Fall, aedeagus: 119, lateral; 120, ventral; 121, ventral operculum.

Figs. 122–127. Agathidium dubitans Fall: Figs. 122–124, punctation details: 122, head; 123, pronotum; 124, elytron. 125. Male metasternal fovea. Figs. 126, 127, habitus: 126, dorsal; 127, lateral. Bars = 0.5 mm.

Figs. 128–131. Agathidium revolvens group species: Figs. 128–130, A. dubitans Fall, aedeagus: 128, lateral; 129, ventral; 130, apex of median lobe and armature of endophallus, ventral aspect. 131. A. dubitanoides, apex of median lobe and armature of endophallus, ventral aspect.