Agathidium tribulosum 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 : 108-109

Agathidium tribulosum Miller and Wheeler , new species Figures 115 , 136 , 232–235 , 363

TYPE MATERIAL: Holotype, Ƌ in CMNC labeled ‘‘GUAT.: QUETZAL­TENANAGO: 12 km SE Zunil, NW face Cerro Zunil. hardwd. for litter. 2700–2760 m. R. Anderson 91­30, 28­V­1991 / HOLOTYPE Agathidium tribulosum Miller and Wheeler, 2003 [red label with black line border]’’.

TYPE LOCALITY: Guatemala, Quetzal­Tenango, 12 km SE Zunil, NW face Cerro Zunil, 2700 m.

DIAGNOSIS: Males of this species are immediately recognizable based on the presence of a long, flat, thornlike spine on the protrochanter (fig. 115) and the metatrochanter which is concave with the apex produced ventrally in a short, but prominent, tubercle. The metasternum is relatively broad medially, flat, and nearly glabrous. The metasternal fovea is minute and located posteriorly. The median lobe is very distinctive with the apex long, sharply pointed, and sharply recurved in lateral aspect (figs. 232, 233). The apex is also slightly bent and twisted (fig. 233), making it uniquely asymmetrical. Both sexes have relatively prominent dorsal punctation consisting of clusters of 2–3 minute punctules.

DESCRIPTION: Body moderately small to moderately large (TBL = 2.93–4.40 mm), broad, robust (PNW/TBL = 0.40 –0.53), strongly contractile.

Head and pronotum testaceous to piceous; elytra testaceous to piceous, lighter apically and along lateral margins; venter red­brown; antennae and palpi yellow.

Head broad (MDL/OHW = 0.57–0.60), 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 dorsoventrally compressed, but still conspicuous; gula slightly concave; antennomere ratios: length I:II:III = 2.6:1.0:1.9, width VII:VIII:IX = 1.0:1.0: 2.1. Pronotum very large, broad (PNL/PNW = 0.72–0.91), strongly convex, anterolateral lobes strongly produced, lateral margin broadly curved, not angulate; surface covered with fine, minute punctures in clusters of 2–3, clusters conspicuous and moderately dense, surface between punctures smooth. Elytra broad, lateral margins strongly round­ ed, apically rounded (SEL/ELW = 0.82– 1.16); punctation similar to pronotum; sutural stria present only at elytral apex. Flight wings strongly reduced. Mesosternum broad, rounded medially; medial carina obsolete anteriorly. Metasternum narrow (MTL/MTW = 0.11–0.20), flattened, strongly sloping dorsad anteriorly; oblique femoral carinae present, but not high, medially not prominent.

Male tarsi 5­5­4; pro­ and mesobasotarsomeres distinctly laterally expanded, protarsomeres more so with large ventral field of spatulate setae; mandibles not modified; protrochanter with ventral, sharp, thornlike spine (fig. 115); apex of metatrochanter produced into deflexed tooth; metafemur moderately broad, with prominent, rounded subapical tooth along posterior margin, posterior margin distinctly serrate (fig. 136); metasternal fovea posterior, small, ovoid, with small pencil of fine setae. Median lobe in lateral aspect elongate, slender, strongly curved basally, relatively straight thereafter, expanded along dorsal and ventral margins submedially, apical portion long, slender, straight basally, apex strongly sinuate, slightly expanded, and hooked ventrally (fig. 234); in ventral aspect slender, narrowed medially, expanded slightly submedially by lateral extension of carina which, together with dorsal carina form a sulcus in which can be placed the lateral lobe, apical portion slender, distinctly asymmetrical, apex twisted and bent to right (figs. 232, 233); operculum in lateral aspect long, straight, and slender, in ventral aspect with margins evenly convergent, apex distinctly, but not deeply, emarginate (fig. 232); lateral lobes long, slender, strongly curved basally, moderately expanded medially, apically broadly sinuate, apex slightly expanded and broadly rounded with 2 stout setae (fig. 235).

Female tarsi 5­4­4.

ETYMOLOGY: This species is named tribulosum, Latin for ‘‘thorny’’, after the thornlike tooth on the male protrochanter.

DISTRIBUTION: This species is known from southern Mexico and Guatemala (fig. 363).

PARATYPES: GUATEMALA: Quetzaltenango: 12 km SE Zunil, NW face Cerro Zunil., 28 May 1991, 2700–2760 m, hardwood forest litter, RS Anderson (38, CNCI).

MEXICO: Chiapas: 7 km SSW Motozintla de Mendoza , 19 Sep 1992, 2000 m, cloud forest litter, RS Anderson (2, CNCI) ; Volcan Tacana , low­ er slopes, ca. 4 km N Union Juarez, 19 Sep 1992, 1950 m, cloud forest litter, RS Anderson (47, CNCI) .

DISCUSSION: The species has been collect­ ed from cloud forest litter and hardwood forest litter. Elevation records are from 1950 to 2760 m.

Figures

Figs. 113–117. Agathidium oniscoides­group species, sterna and legs: 113, A. gomezae, metasternum, arrow indicating medial metasternal lobe. 114, A. skoliosternum, mesosternum, arrow indicating anterior excavation of mesosternal margin. 115, A. tribulosum, Ƌ left proleg, arrow indicating spine on Ƌ left protrochanter. 116, A. tribulograndum, Ƌ left proleg, arrow indicating spine on Ƌ left procoxa. 117, A. framea, Ƌ left metaleg, arrow indicating broad lobe along anterior margin of Ƌ left metacoxa.

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. 232–260. Agathidium oniscoides­group species, aedeagus: 232–235, A. tribulosum: 232, ventral; 233, median lobe, apex, ventral; 234, median lobe, lateral; 235, left lateral lobe, lateral. 236–239, A. tribulograndum: 236, ventral; 237, median lobe, apex, ventral; 238, median lobe, lateral; 239, left lateral lobe, lateral. 240–243, A. invisitatum: 240, ventral; 241, median lobe, apex, ventral; 242, median lobe, lateral; 243, left lateral lobe, lateral. 244–247, A. multidentatum: 244, ventral; 245, median lobe,

Figs. 363, 364. Geographic distribution of Agathidium oniscoides­group species: 363, A. popocatepetlae = -; A. potosii = •; A. stenomma = *; A. tribulosum = ^. 364, A. hyle = *; A. grandidentatum = O; A. multidentatum = •; A. sejunctum = ^; A. tribulograndum = •.