Agathidium dentigerum Horn, 1880

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 : 130-131

Agathidium dentigerum Horn Figures 156 , 303–305 , 371

Agathidium dentigerum Horn, 1880: 303 ; Leng, 1920; Fall, 1934b.

TYPE MATERIAL: Lectotype (designated to fix this name with this species), Ƌ in MCZC labeled ‘‘ Stone Cr. LeeCo Va /269. [handwritten]/ Type 3187 [number handwritten, two­thirds of label red]/ A. dentigerum Horn [handwritten]’’. There is a single ♀ paratype (not examined) with same label data as the holotype ( Horn, 1880).

TYPE LOCALITY: United States, Virginia, Lee Co., Stone Creek.

DIAGNOSIS: This species is similar to other A. dentigerum group members that have a large, acute, somewhat falcate male metafemoral tooth (fig. 156), very narrow metasternum with the oblique metasternal carinae relatively prominent and meeting medially in a large, posteriorly directed triangular lobe, large male metasternal fovea, and somewhat reduced eyes. However, this species has a very prominent lobelike tubercle medially on the gula, making it most similar to A. akrogeneios and A. stephani . From these species it may be distinguished by the shape of the median lobe which has the apical portion strongly recurved dorsally in lateral aspect (fig. 304), much more broadly so than in A. akrogeneios (fig. 310).

DESCRIPTION: Body small (TBL = 2.17– 2.23 mm), rounded, robust (PNW/TBL = 0.47–0.48), strongly contractile.

Head, pronotum, and elytra red; venter yellow­red; antennae, palpi, and legs yellow.

Head broad (MDL/OHW = 0.52–0.59), dorsal surface flattened, dorsoventrally compressed; with very fine punctures, each with a short, very fine seta, surface between punctures shiny, very finely microreticulate; frontoclypeal suture obsolete medially; eyes not strongly reduced, protruding, large­faceted; gula broad, flattened, with prominent median lobelike, tubercle; antennomere ratios: length I:II:III = 1.3:1.0:0.9, width VII:VIII:IX = 1.0:1.0:2.0. Pronotum very large, broad (PNL/PNW = 0.71–0.74), 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, shiny. Elytra broad, lateral margins strongly rounded, apically rounded (SEL/ ELW = 0.94–1.07); punctation similar to pronotum; sutural stria absent. Flight wings strongly reduced. Mesosternum broad, broadly convex; medial carina prominent. Metasternum narrow (MTL/MTW = 0.14– 0.15), medially flat, distinctly sloping dorsad anteriorly; oblique femoral carinae not prominent laterally, medially meeting in very prominent, posteriorly directed triangular flange.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres slightly laterally expanded, with small ventral field of spatulate setae; mandibles not modified; metafemur slender, with large acute, subfalcate tooth subapically on posterior margin (fig. 156); metasternal fovea posterior, large, round with large brush of long, fine setae. Median lobe in lateral aspect moderately broad, basally bent, straight thereafter, apical portion tapered, strongly sinuate, apex finely pointed (fig. 304); in ventral aspect moderately broad, lateral margins slightly curved, apical portion narrowed to broadly pointed apex (fig. 303); operculum divided into two long, slender rami, apices slightly divergent and each narrowly rounded (fig. 303); lateral lobes broad, curved basally, apices rounded with 2 long subapical setae (fig. 305).

Female not examined.

DISTRIBUTION: Agathidium dentigerum is found in Tennessee and Virginia (fig. 371).

SPECIMENS EXAMINED: UNITED STATES: Tennessee: Campbell Co.: Morely, 17 Mar 1976, rotten wood debris, Berlese, QD Wheeler (2, QDWC).

DISCUSSION: A single habitat record is from ‘‘rotten wood debris’’.

Figures

Figs. 145–172. Agathidium oniscoides­group species, left male metafemur, ventral aspect: 145, A. oculeum. 146, A. recurvatum. 147, A. impensum. 148, A. cheneyi. 149, A. tenangoense. 150, A. rumsfeldi. 151, A. hirsutum. 152, A. cortezi. 153, A. tumidiventre. 154, A. aztec. 155, A. iridescens. 156, A. dentigerum. 157, A. stephani. 158, A. akrogeneios. 159, A. appalachium. 160, A. pocahontasae. 161, A. carolinense. 162, A. gallititillo. 163, A. divaricatum. 164, A. bushi. 165, A. georgiaense. 166, A. chauliodoum. 167, A. microphthalmum. 168, A. nimbosilva. 169, A. oniscoides. 170, A. rubellum. 171, A.

Figs. 303–328. Agathidium oniscoides­group species, aedeagus: 303–305, A. dentigerum: 303, ventral; 304, median lobe, lateral; 305, left lateral lobe, lateral. 306–308, A. stephani: 306, ventral; 307, median lobe, lateral; 308, left lateral lobe, lateral. 309–310, A. akrogeneios: 309, ventral; 310, lateral. 311–313, A. framea: 311, ventral; 312, median lobe, lateral; 313, left lateral lobe, lateral. 314–316, A. appalachium: 314, ventral; 315, median lobe, lateral; 316, left lateral lobe, lateral. 317–319, A. pocahontasae: 317, ventral; 318, median lobe, lateral; 319, left lateral lobe, lateral. 320–322, A. carolinense: 320, ventral; 321, median lobe, lateral; 322, left lateral lobe, lateral. 323–325, A. gallititillo: 323, ventral; 324, median lobe, lateral; 325, left lateral lobe, lateral. 326–328, A. divaricatum: 326, ventral; 327, median lobe, lateral; 328, left lateral lobe, lateral.

Figs. 370, 371. Geographic distribution of Agathidium oniscoides­group species: 370, A. pocahontasae. 371, A. appalachium = -; A. dentigerum = •.