Baconia coerulea (Bickhardt, 1917)

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297 : 249-251

Baconia coerulea (Bickhardt, 1917) Figs 73 D–E 76Map 22

Phelister coeruleus Bickhardt, 1917: 215; Baconia coerulea : Mazur 1984: 280.

Type locality.

BRAZIL: Pará [exact locality unknown].

Type material.

Lectotype, here designated (ZMHB): “Pará, 10/2 93" / "coeruleus n. sp. Bickh." / "coeruleus Bickh." / "Phelister coeruleus Bickhardt, 1917 ex. Coll. Schmidt-Bickhardt / “Type” / "LECTOTYPE Phelister coeruleus Bickhardt, M.S.Caterino & A.K.Tishechkin des. 2010". This species was described from an unspecified number of specimens, and the lectotype designation fixes primary type status on the only known original specimen.

Other material.

VENEZUELA, 2: Anzoátegui: Los Naranjos, Rio Neveri (+ or -) 900 m, 25.viii.1966, L. Joly (FMNH, MHNLS); 1: Bolívar: Carret. El Dorado-S. Elena, 6°6'N, 61°23'W, 88 m, 29.ix.1967, L. Joly (MHNLS).

Diagnostic description.

Length: 2.0-2.1mm, width: 1.8-1.9mm; body elongate oval, narrowing anterad, weakly convex, glabrous; head and pronotum weakly metallic blue to greenish-blue, elytra more distinctly metallic blue, pygidia and venter rufobrunneus to rufopiceous; frons elevated more or less transversely above antennal bases, frontal stria complete, obtusely subangulate at middle, frontal disk depressed behind, with very conspicuous ground punctation and few coarser punctures on epistoma and middle of frons, supraorbital stria absent, epistoma convex anteriorly, labrum about 4 ×wider than long, broadly and weakly emarginate apically; both mandibles with small, acute basal tooth; antennal scape short, club slightly asymmetrically elongate oval; pronotal sides rather evenly, weakly convergent in basal two-thirds, abruptly arcuate to apex, marginal stria complete along lateral and anterior margins; lateral submarginal pronotal stria present along basal three-fourths of margin, pronotal disk not depressed mediad, only very narrowly in anterior corners, ground punctation of pronotal disk rather conspicuous, sparsely interspersed with small secondary punctures almost throughout except along midline; elytra with three complete epipleural striae, outer subhumeral stria absent, inner subhumeral stria present in basal two-thirds, may be weakened or interrupted at middle, dorsal striae 1-5 more or less complete but with inner striae increasingly abbreviated apically, sutural stria present in apical three-fourths, may extend faintly to base, elytral disk with coarse punctures in apical third; prosternum narrow, weakly convex, keel emarginate at base, carinal striae convergent between coxae, divergent anterad and posterad; prosternal lobe just over one-half keel length, apical margin rounded, marginal stria obsolete at sides; mesoventrite produced at middle, marginal stria complete, mesometaventral stria arched forward, crenulate, complete, meeting lateral metaventral stria at sides, which curves posterolaterad toward middle of metacoxa, outer lateral metaventral stria about half length of inner stria, oblique, metaventral disk impunctate at middle; abdominal ventrite 1 with single, complete lateral stria, middle portion of disk impunctate; protibia with 4 marginal denticles, outer margin serrulate between; mesotibia with one marginal and 1-2 weak submarginal spines; outer metatibial margin smooth; propygidium without basal stria, discal punctures moderately large, separated by about their diameters in basal half, smaller and sparser apically; propygidial gland openings evident one-third from basal and lateral margins; pygidium with ground punctation fine, rather dense, interspersed with small secondary punctures mainly in basal half, apex of pygidium with distinctive, whorled microsculpture, this possibly more conspicuous in male. Male genitalia (Fig. 76): T8 slightly longer than broad, sides subparallel, basal emargination shallow, basal rim slightly explanate, ventrolateral apodemes reaching longitudinal midpoint beneath, separated by about one-half T8 width; S8 halves fused near bases, inner margins diverging apically, sides curved outward slightly to apex, apical guides well developed, similar in width from midpoint to apex, apices connected by ventral velar membrane; T9 with proximal apodemes about one-third total length, dorsal lobes narrowed apically, with convergent, subacute apices, ventrolateral apodemes weakly developed; S9 desclerotized along midline in apical half, sides narrowed to base, apical arms divergent, obliquely subquadrate; tegmen elongate, narrow at base, widened one-fourth from base, weakly curved to apex, weakly curved ventrad near apex; median lobe simple, very short; basal piece about one-third tegmen length.

Remarks.

Baconia coerulea may be distinguished by its elongate ovoid body form (Fig. 73D), its nearly complete lateral submarginal pronotal stria, 5 more or less complete elytral striae, and distinctive (possibly sexually dimorphic) apical pygidial microsculpture (Fig. 73E).

This species is generally similar to members of the Baconia godmani group, but differences in a number of characters make this ambiguous: more convex body, non-depressed frons, complete lateral submarginal pronotal stria, transversely carinate labrum, and lack of distinct setal fringe along the male’s 8th sternite. However, the brief fusion of the bases of the halves of the 8th sternite bear some resemblance to the completely fused sternite of Baconia dives , Baconia eximia , and Baconia varicolor , and this may be a significant indicator of their relationship.