Agathidium nimbosilva 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 : 148-149

Agathidium nimbosilva Miller and Wheeler , new species Figures 111 , 168 , 341–343 , 376

TYPE MATERIAL: Holotype, Ƌ in CMNC labeled ‘‘ GUATEMALA: BAJA VERAPAZ: 7 km E Purulha. Elev. 1600 m. cloud for. litter. R. Anderson 91­15 23­V­1991 /HO­ LOTYPE Agathidium nimbosilva Miller and Wheeler, 2003 [red label with black line bor­ der]’’. Only a single specimen is known of this species.

TYPE LOCALITY: Guatemala, Baja Verapaz, 7 km E Purulha.

DIAGNOSIS: Males of this species may be distinguished from most species by the strongly reduced eyes consisting of minute, slightly elongate triangles (fig. 111), a small but distinct and sharp metafemoral tooth (fig. 168), and distinctive male genitalia with the median lobe moderately robust and with the apex slender and approximately straight (fig. 342). The species is most similar to A. chauliodoum and A. microphthalmum , from which it may be distinguished by smaller eyes, less laterally expanded male probasotarsomeres (both to distinguish it from A. chauliodoum ), a smaller metafemoral tooth and differences in the shape of the median lobe (figs. 341, 342).

DESCRIPTION: Body small (TBL = 2.16 mm), broad, robust (PNW/TBL = 0.49), rounded, strongly contractile.

Head dark red­brown; pronotum dark redbrown medially, red along margins; elytra dark red­brown medially, red along margins, not iridescent; venter, antennae, palpi, and legs yellow.

Head broad (MDL/OHW = 0.55), 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 strongly reduced to small triangles, only a few facets present (fig. 111); gula flattened, not modified; antennomere ratios: length I:II:III = 1.2:1.0:1.7, width VII:VIII:IX = 1.0:1.0:2.2. Pronotum very large, broad (PNL/PNW = 0.74), 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 = 0.98); punctation and surface similar to pronotum; sutural stria absent. Flight wings strongly reduced. Mesosternum moderately broad, not declivitous; medial carina well developed. Metasternum narrow (MTL/MTW = 0.12), flat medially, distinctly dorsally sloped anteriorly; oblique femoral carinae well developed, meeting medially in low, but prominent carina.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres not strongly laterally expanded, equally so and with a moderate field of ventral spatulate setae; mandibles not modified; metafemur moderately broad, with very large, flat, triangular tooth subapically on posterior margin (fig. 168); metasternal fovea moderately large, transversely oval with dense brush of long fine setae. Median lobe in lateral aspect moderately short, stout, strongly curved basally, straight in medial portion apically flexed dorsad, apical portion slender, straight, apex slender and pointed (fig. 342); in ventral aspect parallel­sided for most of length, apex evenly tapered to narrowly rounded apex (fig. 341); operculum broad, flat, apically broadly rounded (fig. 341); lateral lobes long, slender, strongly curved basally, apically with 2 stout setae (fig. 343).

Female not observed.

ETYMOLOGY: Named from the Latin words nimbus, meaning ‘‘rain cloud’’, and silva, meaning ‘‘forest’’, for the habitat where the type specimen was collected.

DISTRIBUTION: This species is known only from the type locality in Baja Verapaz, Guatemala (fig. 376).

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

Agathidium oniscoides Subgroup DISCUSSION: These species are not characterized by any particularly discrete characters, but share a general similarity in body form and aedeagal shape. There are two species pairs in this group. One of these is A. oniscoides and A. rubellum , which have nearly identical male genitalia and relatively short elytral sutures. The other two are A. fawcettae and A. exiguum , which have dorsal microreticulation, relatively long elytral sutures and somewhat similar genitalia. These are some of the most common species in North America.

Agathidium oniscoides Palisot de Beauvois

Figures

Figs. 106–112. Agathidium oniscoides­group species, heads, left lateral aspect: 106, A. vaderi. 107, A. kimberlae. 108, A. oculeum. 109, A. stenomma. 110, A. microphthalmum. 111, A. nimbosilva. 112, A. chauliodoum. Bars = 0.5 mm.

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. 329–356. Agathidium oniscoides­group species, aedeagus: 329–313, A. bushi: 329, ventral; 330, median lobe, lateral; 331, left lateral lobe, lateral. 332–334, A. georgiaense: 332, ventral; 333, median lobe, lateral; 334, left lateral lobe, lateral. 335–337, A. chauliodoum: 335, ventral; 336, median lobe, lateral; 337, left lateral lobe, lateral. 338–340, A. microphthalmum: 338, ventral; 339, median lobe, lateral; 340, left lateral lobe, lateral. 341–343, A. nimbosilva: 341, ventral; 342, median lobe, lateral; 343, left lateral lobe, lateral. 344–347, A. oniscoides: 344, ventral; 345, apex of median lobe, ventral, specimen from Macon City, NC; 346, median lobe, lateral; 347, left lateral lobe, lateral. 348–350, A. rubellum: 348, ventral; 349, median lobe, lateral; 350, left lateral lobe, lateral. 351–353, A. exiguum: 351, ventral; 352, median lobe, lateral; 353, left lateral lobe, lateral. 354–356, A. fawcettae: 354, ventral; 355, median lobe, lateral; 356, left lateral lobe, lateral.

Fig. 376. Geographic distribution of Agathidium oniscoides­group species: A. chauliodoum = -; A. microphthalmum = •; A. nimbosilva = *.