Baconia aenea, 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 : 263-266

Baconia aenea sp. n. Figs 82 C–D83A–C, G, I–JMap 23

Type locality.

FRENCH GUIANA: Montagne des Chevaux [4.72°N, 52.40°W].

Type material.

Holotype male: "GUYANE FRANÇAISE: Montagne des Chevaux, 4°43'N, 52°24'W, Piège d’interception 13 Jun 2009. SEAG leg." / "Caterino/Tishechkin Exosternini Voucher EXO-00425" (MNHN). Paratypes (65): FRENCH GUIANA: 4:Montagne des Chevaux, 4°43'N, 52°24'W, 26.xii.2008, 3: 4.i.2009, 1: 9.i.2009, 2: 10.i.2009, 1: 19.i.2009, 4: 25.i.2009, 2: 8.ii.2009, 3: 23.ii.2009, 1:8.iii.2009, 1: 15.iii.2009, 2:18.iv.2009, 1: 20.iv.2010, 1: 25.iv.2009, 1:2.v.2009, 1:16.v.2009, 1:13.vi.2009, 1: 20.vi.2009, 2:27.vi.2009, 4:4.vii.2009, 7:11.vii.2009, 3:19.vii.2009, 4:27.vii.2009, 1: 1.viii.2009, 2:9.viii.2009, 1:19.ix.2009, 1: 10.i.2010, 1: 10.ix.2010, 1: 9.i.2011, 1: 13.ii.2011; 1: Bélvédère de Saül, 3 °1'22"N, 53°12'34"W, 7.ii.2011, 1: 14.ii.2011, 1: 17.i.2011; 1: Rés. des Nouragues, Régina, 4°2.27'N, 52°40.35'W, 28.i.2010, 1:19.ii.2010; 2:Mont tabulaire Itoupé, 3°1.82'N, 53°6.40'W, 400 m, 31.iii.2010 (all FIT, coll. by SEAG; MNHN, CHND, FMNH, MSCC, AKTC).

Other material.

1: PERU: Loreto, 45 km SW Iquitos, Rio Ucayali, Genaro Herrera, 4°54'S, 73°40'W, FIT, 31.vii.2011, G.Lamarre (CHND).

Diagnostic description.

Length: 2.0-2.3mm, width: 1.7-2.1mm; body broadly elongate oval, sides subparallel, moderately depressed, glabrous; head, pronotum and elytra uniformly metallic dark bronze, many individuals with hints of violet, pygidia and venter rufo-piceous; frons broad, rounded above, with interocular margins strongly convergent dorsad, weakly elevated above antennal bases, depressed at middle, ground punctation conspicuous, secondary punctures small, sparse, few at center and near vertex, frontal stria fine, present along inner margin of eye, absent across front; supraorbital stria absent though may be vaguely indicated by series of punctures; epistoma with apical margin weakly emarginate; labrum only about 2.5 ×wider than long, distinctly bilobed, emarginate in middle; apices of mandibles prolonged, each mandible with acute basal tooth; antennal scape short, club nearly circular; pronotal sides subparallel in basal third, evenly arcuate to apex, only weakly depressed in anterior corners, marginal stria complete along lateral and anterior margins, slightly crenulate in front, lateral submarginal stria absent, ground punctation of pronotal disk very fine at middle, secondary punctures uniformly interspersed in lateral thirds; elytra with 2 complete epipleural striae, outer subhumeral stria absent, inner subhumeral stria present as basal and medial fragments, dorsal striae 1-3 more or less complete, 4th stria variably abbreviated from apex, less commonly complete, 5th stria generally present as very short basal fragment, may arch basally toward suture, sutural stria present in apical two-thirds to three-fourths, elytral disk with coarse punctures in apical third; prosternum rather narrow, distinctly convex, keel shallowly emarginate at base, carinal striae nearly complete, may be abbreviated anteriorly, slightly convergent toward front; prosternal lobe about two-thirds keel length, apical margin rather narrowly rounded, marginal stria well impressed, obsolete at extreme sides; mesoventrite sinuate to weakly produced at middle, marginal stria complete, mesometaventral stria weakly arched forward, crenulate, continuous at sides with lateral metaventral stria, which curves posterolaterad toward middle of metacoxa, outer lateral metaventral stria present, short, divergent from base of inner stria, metaventral disk impunctate at middle; abdominal ventrite 1 with single lateral stria more or less complete, disk with few secondary punctures along apical margin; protibia 4-dentate, basal denticle weak, outer margin serrulate between teeth; mesotibia with two marginal spines; outer metatibial margin smooth; propygidium with transverse basal stria complete, discal punctures moderately large at middle, ocellate, separated by about their diameters, smaller and sparser toward sides; propygidial gland openings small but evident behind ends of transverse stria, one-fourth from lateral margins; pygidial sculpturing sexually dimorphic, that of female uniformly, rather densely covered with secondary puntation, that of the male less densely punctate throughout and with two weakly depressed areas on either side of midline in basal half devoid of secondary punctures but with very dense, fine ground punctures. Male genitalia (Figs 83 A–C, G, I–J): T8 slightly longer than wide, sides weakly convergent to apex, basal emargination rather deep, sinuate, apical emargination very shallow, ventrolateral apodemes extending only about one-third distad from base, separated by about one-half T8 width; S8 halves approximate in basal half, narrowing to apex, sides converging apically, apical guides narrow; T9 with proximal apodemes obsolete, dorsal lobes narrowing gradually to base, apices narrowly subacute, ventrolateral apodemes weakly dentate beneath; S9 desclerotized along basal two-thirds of midline, stem moderately broad, widening slightly toward base, apical arms slightly divergent, apices acute; tegmen narrow, sides weakly converging to apex, rather thick, very weakly curved in lateral aspect; median lobe simple, one-half tegmen length; basal piece long, one-half tegmen length.

Remarks.

This distinctive species is closely related to Baconia purpurata , but the broader frons (Fig. 82D), large and distinctly bilobed labrum, complete basal propygidial stria, presence of a short basal fragment of the 5th elytral stria, bronzy rather than distinctly violet coloration (Fig. 82C), and unique pygidial dimorphism will easily distinguish it. It has been the most abundantly collected species of Baconia in French Guiana. The single specimen (female) from Peru is a somewhat surprising geographic outlier, but it does differ in a few characters, most notably having more distinctly violet colored elytra than most members of Baconia aenea , as well as having the sutural stria complete and meeting the basal arch of the 5th stria. Therefore we exclude it from the type series. Discovery of a male from near its locality would help evaluate its status.

Etymology.

This species’ name refers to its distinct bronzy coloration.