Baconia crassa, Caterino, Michael S. & Tishechkin, Alexey K., 2013

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297: 97-99

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scientific name

Baconia crassa

sp. n.

Baconia crassa   sp. n. Figs 26 C–D27D–F, H, K–LMap 7

Type locality.

BRAZIL: Rio de Janeiro: Nova Friburgo [22.26°S, 42.53°W].

Type material.

Holotype male: "BRAZIL: Rio de Janeiro, Nova Friburgo, 22°16'S, 42°32'W, piege d’interception 26-31 Oct 2009" / "Caterino/Tishechkin Exosternini Voucher EXO-00484" (UFPR). Paratype (1): same data as type (UFPR).

Other material.

1: Mato Grosso:Mpio. Claudia, 11°24.5'S, 55°19.5'W, 17-27.x.2010, FIT, A.F. Oliveira (CEMT).

Diagnostic description.

Length: 1.9-2.2mm, width: 1.7-2.0mm; body rather broadly elongate oval, convex, glabrous; faintly bicolored, with elytra rufopiceous, rest of body piceous, shining; frons elevated over antennal bases, depressed in middle, interocular margins convergent dorsad, epistoma convex and finely, densely punctate, frontal disk with few coarse punctures in median depression, frontal stria present along inner edges of eyes, largely absent between antennal bases, may be represented by few median fragments; supraorbital stria fine, rudimentary; antennal scape short, thick, club oblong, widened toward apex; labrum with upper edge weakly carinate, emarginate, lower margin narrowed, recessed between mandibles; mandibles rather short, each with small basal tooth; pronotal sides weakly arcuate in basal two-thirds, more strongly arcuate to apices, lateral marginal striae continuous around sides and front, submarginal stria absent, anterior corners of pronotal disk weakly depressed, coarser secondary punctures of pronotal disk extending across anterior half, sides, and along basal margin, relatively impunctate only in small area posteromedially; elytra with two complete epipleural striae and fragments of third (outermost), outer subhumeral stria absent, inner subhumeral stria present as short basal fragment, dorsal striae 1-2 more or less complete, 2nd stria may be weakly abbreviated basally, 3rd stria in basal half only, scratchlike, 4th and 5th striae absent, sutural stria present for short distance at middle, elytral disk with coarse punctures diminishing from apex nearly to midline; prosternal keel moderately broad, weakly convex, shallowly emarginate at base, carinal striae convergent between coxae, complete, free; prosternal lobe short, about one-half keel length, apical margin rounded, marginal stria well impressed at middle, obsolete at sides; mesoventrite weakly produced at middle, marginal stria complete; mesometaventral stria weakly arched forward at middle, crenulate, continued laterally by inner lateral metaventral stria toward middle of metacoxa, slightly abbreviated at apex, outer lateral metaventral stria subparallel, about half as long; metaventral and abdominal disks impunctate at middle; abdominal ventrite 1 with inner lateral stria abbreviated apically, outer lateral stria absent; protibiae 4-dentate, middle pair of spines more widely separated, outer margin finely serrulate; meso- and metatibiae moderately expanded apically, mesotibia with one marginal spine; outer metatibial margin smooth; propygidium lacking basal stria, with coarse secondary punctures separated by slightly less than their diameters near basal margin, much sparser posterad, propygidial glands inconspicuous; pygidium with fine ground punctation very sparsely interspersed with small secondary punctures mainly in basal half. Male genitalia (Figs 27 D–F, H, K–L): T8 shorter than broad, sides broadly arcuate, basal emargination broad, moderately deep, basal rim well sclerotized, explanate, basal membrane attachment line visible at sides, apex shallowly emarginate, ventrolateral apodemes projecting weakly beneath, about one-third from base, separated by about two-thirds maximum T8 width, rapidly narrowed apically; S8 divided, inner margins approximate only at base, divergent apically, outer margins weakly rounded, convergent, apical guides slightly widened distally, narrowly rounded at apices, apical velar membrane absent, apex lacking conspicuous setae; T9 with basal apodemes rather thin and elongate, just over one-third total length, T9 apices narrowly rounded, glabrous, ventrolateral apodemes weakly projecting beneath; S9 with stem narrowest near midpoint, faintly widened to base, more strongly to apex, apical emargination arcuate, apex broadly desclerotized at middle, intermediate in sclerotization along entire midline; tegmen with sides subparallel, weakly narrowed to blunt apices, tegmen in lateral aspect more or less straight, weakly curved ventrad at tip; median lobe simple, about one-half tegmen length; basal piece short, about one-fourth tegmen length.


In addition to the diagnostic characters pertaining to the frons of this species (Fig. 26C), given under Baconia turgifrons   above, the more widespread secondary punctures of the pronotum (Fig. 26D) will distinguish Baconia crassa   . The type specimens are somewhat more rufopiceous than strictly piceous in color. The single individual from Mato Grosso exhibits a lower density of epistomal punctation, and is piceous, and so is excluded from type series. More material might support separation, but in any case it is clearly closely related.


This species’ name refers to its wide-bodied shape, crassa meaning literally fat or plump.