Baconia dives (Marseul, 1861)

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297 : 74-76

Baconia dives (Marseul, 1861) Figs 18B19 C–D, J, NMap 5

Phelister dives Marseul, 1861: 157 (cited in error as 'Marseul, 1862: 706' by Mazur 1997); Baconia dives : Mazur 1984: 280.

Type locality.

BRAZIL: Rio de Janeiro: [22.9°S, 43.2°W].

Type material.

Lectotype, sex undetermined, here designated (NHRS): "Rio Jan." / "F. Sahlb." / “Type” / “Typus” / "NHRS-VKBS 000000004" / "6903 E91 + " / "LECTOTYPE Phelister dives Marseul, M.S.Caterino & A.K.Tishechkin des. 2010". Paralectotype: same data as type, NHRS-VKBS000000005. This species was described from an unspecified number of specimens, and the lectotype designation fixes primary type status on one of the original specimens.

Other material.

BOLIVIA, 1: Santa Cruz:Hotel Flora y Fauna, 4-5 km SSE Buena Vista, 17°29.925'S, 63°39.128'W, 440 m, 6-15.xii.2003, FIT, forest, S. & J. Peck (CMNC). BRAZIL: 1: Amazonas: Igarape Belem, nr. Rio Solimoes, 70 km E, of Leticia, 18-28.v.1970, under bark, B. Malkin (FMNH); 1: Rio Janauaca, 40 km SW Manaus, 03°20'S, 060°17'W, 10.iii.1979, fogging white water inundation forest canopy, T. Erwin (USNM); 1: Pará: Santarém (CMNH). COLOMBIA, 2: Meta: Villavicencio, 11.vii.1938, under bark, H. Dybas (FMNH); 1: 13.vii.1938, C. Seevers (USNM), 1: 25.vii.1938, under bark, H. Dybas (FMNH). FRENCH GUIANA: Belvèdére de Saül, 3°1'22"N, 53°12'34"W, 10.xii.2010, FIT, SEAG (CHND). MEXICO: 1: San Luis Potosí:intercepted in route to Texas, orchid del maiz (USNM). VENEZUELA, 2: Anzoátegui: Los Naranjos, Rio Neveri (+ or -) 900 m, 25.viii.1966, L. Joly (MHNLS). PERU: Loreto: Iquitos, Rio Nanay, 4-6.ii.1984, L. Huggert (MHNG).

Diagnostic description.

Length: 2.2-2.6mm, width: 1.9-2.2mm; body elongate oval, weakly depressed, glabrous; dorsum metallic, more or less uniformly blue to blue-violet; frons elevated over antennal bases, rather strongly depressed along antero-posterior midline, ground punctation rather conspicuous, with few moderately large secondary punctures within frontal depression, frontal stria present along inner margin of eye, curving mediad, interrupted at middle, supraorbital stria absent; antennal scape short; epistoma depressed in middle, slightly convex along distal margin, truncate to weakly emarginate; labrum about 3 ×wider than long, weakly emarginate to bisinuate along apical margin; both mandibles with acute basal tooth; pronotal sides increasingly arcuate to apex, depressed in extreme anterior corners, marginal stria complete along lateral and anterior margins, crenulate in front, lateral submarginal stria absent, ground punctation of pronotal disk rather conspicuous, interspersed with small secondary punctures along front and toward sides; elytra with three complete epipleural striae, outer subhumeral stria absent, inner subhumeral stria present as basal and median fragments, dorsal striae 1-4 more or less complete, inner striae weakly abbreviated from apices, 4th stria arched mediad at base, 5th stria mostly absent, may be represented by basal puncture, sutural stria present in apical two-thirds, elytral disk with coarse punctures in apical fourth; prosternum weakly convex, keel weakly emarginate at base, carinal striae complete, divergent anterad and posterad, separate throughout; prosternal lobe slightly over one-half keel length, weakly deflexed, apical margin rather narrowly rounded, marginal stria obsolete at sides; mesoventrite weakly produced at middle, marginal stria complete, mesometaventral stria arched forward, crenulate, interrupted at middle, laterally meeting lateral metaventral stria, which extends posterolaterad toward middle of metacoxa, sinuate apically, outer lateral metaventral stria very short, oblique, metaventral disk impunctate at middle; abdominal ventrite 1 with single lateral stria, abbreviated apically, middle portion of disk impunctate; protibia 4-5 dentate, basal denticles weak, outer margin serrulate between teeth; mesotibia with one prominent and one weak marginal spine; outer metatibial margin smooth; propygidium without basal stria, discal punctures rather small, ocellate, separated by 1 –2× their diameters, sparser apically; propygidial gland openings rather conspicuous one-third from basal and lateral margins; pygidium with ground punctation very fine, interspersed with small secondary punctures mainly in basal third. Male genitalia (Figs 19 C–D, J, N): T8 slightly longer than broad, sides subparallel, more or less straight, with superficial dorsal sclerotizations in basal half, basal emargination narrowly rounded, apical emargination deep, subacute, basal rim slightly explanate, ventrolateral apodemes separated by about one-half maximum T8 width, extending beneath to about one-third from base; S8 elongate, halves fused along midline, with weakly expanded, membraneous apical velum bearing a dense setal fringe, apical guides moderately well developed, widest near middle, narrowly rounded apically; T9 with basal apodemes moderately thick, about one-half total T9 length, apices subacute, glabrous, ventrolateral apodemes weakly produced beneath; S9 stem parallel-sided, strongly desclerotized along midline; tegmen with sides widest near apex, sinuately narrowed toward base (as in Baconia varicolor ), in lateral aspect slightly thickened near middle, very weakly curved toward apex; median lobe nearly one-half tegmen length; basal piece about one-third tegmen length.

Remarks.

Baconia dives is a relatively large, convex, laterally rounded species (Fig. 18B). It is best recognized by the elytral striation, with the inner subhumeral and striae 1-4 largely complete (though they may be weakly abbreviated from their apices), with the base of the 4th stria arched slightly mediad, the 5th stria represented by only a basal puncture, and the sutural stria present in the apical two-thirds. It lacks submarginal pronotal or basal propygidial striae, and has its mesometaventral stria weakly arched forward and finely crenulate across the middle (rarely interrupted). In this species, as well as in Baconia eximia , Baconia varicolor (and perhaps a few others of the above whose males are not known), the halves of the 8th sternite are fused along part of the midline.