Agathidium compressidens Fall, 1934b: 106

MILLER, KELLY B. & WHEELER, QUENTIN D., 2005, Slime-Mold Beetles Of The Genus Agathidium Panzer In North And Central America, Part Ii. Coleoptera: Leiodidae, Bulletin of the American Museum of Natural History 2005 (291), pp. 1-167 : 68-69

Agathidium compressidens Fall, 1934b: 106 .

TYPE MATERIAL: Holotype, ♀ in MCZC labeled ‘‘ Round Knob N.C. 6124 [handwritten]/ ♀ / TYPE compressi­dens [name handwritten, red line under ‘‘TYPE’’]/ M.C.Z. Type 24033 [number handwritten, red label]/ H.C. FALL COLLECTION’’.

TYPE LOCALITY: United States, North Carolina, Round Knob.

DIAGNOSIS: This species is distinguishable by the presence of a prominent lobe medially on the ventral surface of the first visible abdominal sternite and by the shape of the male genitalia. The median lobe of the aedeagus is very robust, the apical portion is broad, flat, and apically pointed (fig. 99), and the operculum is broad, flat, and broadly round­ ed apically with a deep, narrow medial emargination (fig. 99). The species is most similar to A. vesperpressidens from which it may be distinguished by the shape of the aedeagus. Also, A. vesperpressidens is generally small­ er (TBL <2.7 mm).

DESCRIPTION: Body moderately large, broad (TBL = 2.84–3.38 mm), robust (PNW/TBL = 0.48–0.49), rounded, strongly contractile.

Head and pronotum red; elytra red, not iridescent; venter yellow to yellow­red; antennae, palpi, and legs yellow.

Head broad (MDL/OHW = 0.58–0.61), dorsal surface flattened, dorsoventrally compressed; with very fine punctures, each with a short, very fine seta, surface between punctures shiny, smooth; frontoclypeal suture obsolete medially; eyes protruding and prominent, large, finely faceted; gula slightly concave, unmodified; clypeus strongly excavate; antennomere ratios: length I:II:III = 1.6:1.0: 1.1, width VII:VIII:IX = 1.1:1.0:2.3. Pronotum very large, broad (PNL/PNW = 0.58– 0.61), strongly convex, anterolateral lobes strongly produced, lateral margin broadly curved, not angulate; with very fine, sparse punctures, each with a short, very fine seta, surface between punctures smooth. Elytra broad, lateral margins strongly rounded, apically rounded (SEL/ELW = 0.94–1.01); punctation similar to pronotum; sutural stria absent to faintly present only apically. Flight wings fully developed. Mesosternum broad, anterior portion longer than posterior portion; distinctly concave posteriorly, but not strongly declivitous; medial longitudinal carina well developed on anterior portion. Metasternum narrow medially (MTL/MTW = 0.14–0.16), subhorizontal, slightly convex medially; oblique femoral carinae faint, not meeting medially. Abdominal sternite III (first visible sternite) with prominent medial lobe.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres slightly laterally expanded, with small field of ventral spatulate setae; mandibles not modified; metafemur relatively slender, with very small subapical tooth on posterior margin; metasternal fovea moderately large, prominent, transversely ovoid, with pencil of long, fine, dense setae, located posterad of middle of metasternum. Median lobe in lateral aspect very robust, strongly curved medially, apical portion slender, curved dorsad, apex pointed (fig. 100); in ventral aspect very broad, apical portion broad, short, narrowed to pointed apex (fig. 99); operculum large, flat, rounded (fig. 99); lateral lobes small, slender, curved, much shorter than median lobe, each with 2 long, stout subapical setae (figs. 99, 101).

Female tarsi 5­4­4.

DISTRIBUTION: This species is known from eastern North America from Ontario and Manitoba to New Hampshire and south to South Carolina and Tennessee (fig. 104).

SPECIMENS EXAMINED: CANADA: Manitoba: Rennie, Lily Pond, Whiteshell Prov. Park, 6 Jun 1984, maple­poplar forest, FIT, S and J Peck (1, PECK). Ontario: Chaffeys Locks QUBS, 2 Sep 1980, litter, on ‘‘fleshy fungi’’, S Peck (1, CNCI).

UNITED STATES: New Hampshire: White Mts , woods (1, MCZC) ; Coos Co.: Jefferson Notch , 19 Sep 1974, 3000̍, under conifer bark, A Newton, JF Lawrence (1, MCZC) ; Grafton Co.: Hubbard Brook Exp. Forest, Bear Brook , 15 Oct 1982, leaf litter, DS Chandler (1, DENH). North Carolina: Round Knob, 24 June (1, MCZC) ; Appalachian Trail to Clingman’s Dome , 19 Aug 1981, on Comatrichia ­like slime mold, QD Wheeler (1, QDWC). South Carolina: Oconee Co.: 12 mi NW Walhalla Oconee St Park, 5 Jun 1981, 1700̍, log­bark litter, 1, S Peck (1, CNCI). Tennessee: Cocke Co. : GSMNP, Albright Grove Tr. 83°16̍45̎W, 35°44̍10̎N, 19 Oct 2001, 1000 m, decid stump, Carlton (2, LSAM). Virginia: Giles Co. : Mtn Lake Biol. Sta. , 15 Sep 1990, 3700̍, on Arcyria denudata, SL Stephenson (1, QDWC) .

DISCUSSION: This species was described from female specimens only. However, we are confident in the assignment of male specimens to this species since we were able to examine a male and female in the same series. The species is relatively rare in collections, and the longest series of specimens examined was two. Specimens have been collected from June to October. They have been found from under conifer bark and from various litter sources including maple­poplar forest, leaves, logs and bark, and a deciduous stump. Elevation records are from 1700 to 3000 ft. Host records include a ‘‘fleshy fungus’’, Arcyria denudata , and a Comatricha ­ like slime mold.