Agathidium lobosternum Miller and Wheeler, 2005

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 : 103

Agathidium lobosternum Miller and Wheeler , new species Figures 131 , 216–218, 362

TYPE MATERIAL: Holotype, Ƌ in CMNC labeled ‘‘ MEX:Hgo ; Tlanchinol 43 km SW Huejutla, 1500 m 14. VI.83. S&J.Peck cloud forest litter/ HOLOTYPE Agathidium lobosternum Miller and Wheeler, 2003 [red label with black line border]’’. Unfortunately, the single specimen examined of this species is in several pieces glued to a point .

TYPE LOCALITY: Mexico, Hidalgo, Tlanchinol 43 km SW Huejutla.

DIAGNOSIS: Members of this species have a distinctive tubercle medially near the anterior margin of the gula and a very prominent lobe formed where oblique femoral carinae of the metasternum meet medially. The male genitalia are fairly simple, slender and with the lateral sulcus on the median lobe for reception of the lateral lobe only very weakly developed (fig. 217).

DESCRIPTION: Body moderately large (TBL = 2.85 mm), broad (PNW/TBL = 0.38), robust, rounded, strongly contractile.

Head and pronotum dark red­brown; elytra dark red­brown, not iridescent; venter yellow­brown; antennae, palpi and legs yellow.

Head broad (MDL/OHW = 0.86), dorsal surface flattened, dorsoventrally compressed; with very fine punctures, each with a short, very fine seta, surface between punctures shiny, very lightly microreticulate; frontoclypeal suture obsolete medially; eyes dorsoventrally distinctly compressed; gula flat, anterior margin with small, prominent tumidity, anterior surface of tumidity with slight fovea; antennomere ratios: length I:II:III = 1.3:1.0: 1.3, width VII:VIII:IX = 1.0:1.0:2.2. Pronotum very large, broad (PNL/PNW = 0.98), strongly convex, anterolateral lobes strongly produced, lateral margin broadly curved, not angulate; with fine, sparse punctures, each with a short, very fine seta, surface between punctures shiny, smooth. Elytra broad, lateral margins strongly rounded, apically rounded (SEL/ELW = 1.02); punctation and surface similar to pronotum; sutural stria absent. Flight wings strongly reduced. Mesosternum moderately broad, not declivitous; medial carina well developed, obscured anteriorly. Metasternum narrow (MTL/MTW = 0.13), slightly concave medially, distinctly dorsally sloped anteriorly; oblique femoral carinae prominent, well­developed, medially meeting in very prominent, narrowly­rounded, posteriorly­directed lobe.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres slightly laterally expanded, with small ventral field of spatulate setae; mandibles not modified; metafemur moderately broad, with small tooth subapically along posterior margin (fig. 131); metasternal fovea large, transversely oval with large brush of fine, long setae. Median lobe in lateral aspect slender, curved basally, slightly constricted medially and expanded thereafter, with weak lateral sulcus for reception of lateral lobe, apical portion of median lobe short, sinuate, slender, apex pointed and hooked ventrad (fig. 217); in ventral aspect slender, slightly narrowed medially, apical portion broad, evenly tapered to pointed apex (fig. 216); operculum flat, moderately broad, lateral margins curved to rounded apex (fig. 216); lateral lobes slender, curved medially, apically slightly sinuate, apices narrowly round­ ed, each with 2 stout setae (fig. 218).

Female not examined.

ETYMOLOGY: Named from the Greek words lobos, meaning ‘‘lobe’’, and sternum, meaning ‘‘chest’’, for the lobe formed where the oblique femoral carinae of the metasternum meet medially.

DISTRIBUTION: This species is known only from Hidalgo (fig. 362).

DISCUSSION: The single observed specimen was collected at 1500 m from cloud forest litter.

Figures

Figs. 118–144. Agathidium concinnum­ and A. oniscoides­group species, left male metafemur, ventral aspect: 118, A. concinnum. 119, A. kimberlae. 120, A. vaderi. 121, A. bituberculum. 122, A. oedema. 123, A. gomezae. 124, A. hidalgoense. 125, A. skoliosternum. 126, A. erythromelas. 127, A. rhamphastes. 128, A. megoniscoides. 129, A. grumum. 130, A. triangularum. 131, A. lobosternum. 132, A. potosii. 133, A. popocatepetlae. 134, A. hyle. 135, A. stenomma. 136, A. tribulosum. 137, A. tribulograndum. 138, A. invisitatum. 139, A. multidentatum. 140, A. sejunctum. 141, A. grandidentatum. 142, A. andersoni. 143, A. disgregum. 144, A. oaxacaense. Bars = 0.5 mm.

Figs. 361, 362. Geographic distribution of Agathidium oniscoides­group species: 361, A. erythromelas = •; A. rhamphastes = -; A. triangularum = ^. 362, A. grumum = -; A. lobosternum = ^; A. megoniscoides = *.