Baconia piluliformis, 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: 197-198

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scientific name

Baconia piluliformis

sp. n.

Baconia piluliformis   sp. n. Figs 54G55E, G, JMap 17

Type locality.

BRAZIL: Manaus: INPA [2.41°N, 59.83°W].

Type material.

Holotype male: "BRAZIL:Manaus,AM. INPA/Smithsonian Res. 2°25'S, 59°50'W R.Didham.iv.1994" / "Leaf litter. Winkler method. Terra firme fst." / "536 | 3" / “0463” / "Caterino Tishechkin Exosternini Voucher EXO-00495" (BMNH). Paratypes (6): BRAZIL: 1: Amapá: Serra do Navio, 0°59'N, 52°00'W, 1-14.v.1991, FIT (CHND). FRENCH GUIANA: 2: Rés. des Nouragues, Camp Inselberg, 4°05'N, 52°41'W, 25.i.2011, FIT, SEAG (MNHN, AKTC); 2: Belvèdére de Saül, 3°1'22"N, 53°12'34"W, 7.ii.2011, FIT, SEAG (CHND, MSCC). 1: SURINAME: Commewijne: Akintosoela, 32 km SE SURINAME River Bridge, road to Redi Doti, 5°16'17"N, 54°55'15"W, 40 m,, FIT, Z. Falin, B. DeDijn, A. Gangadin (SEMC).

Diagnostic description.

Length: 1.4-1.5mm, width: 1.2-1.3mm; body elongate oval, strongly convex, glabrous; color rufescent, shining; head with frons elevated over and between antennal bases, narrowly depressed at middle, interocular margins convergent dorsad, frontal disk mostly impunctate, with few punctures at sides and along dorsal margin, frontal stria represented by short fragment along upper margin of eyes, supraorbital stria short, irregular; antennal scape very short, club large, elongate oval; epistoma narrowly transversely depressed beneath antennal bosses, apical margin truncate; labrum about 3 ×wider than long, apical margin deeply emarginate; mandibles short, each with minute, acute basal tooth; pronotum transverse, short, with sides strongly arcuate to apex, lateral marginal stria descending to ventral edge about one-third behind anterior corner, extending around corner to meet anterior marginal stria, which is recurved posterad about one-third pronotal length behind each eye, the median pronotal gland opening displaced posterad to near its apex, lateral submarginal stria nearly complete, merging with marginal stria or ending freely, pronotal disk with ground punctation fine, very sparse, with small secondary punctures mainly in anterolateral corners; elytra with upper epipleural stria complete, the lower somewhat fragmented, outer and inner subhumeral striae absent, dorsal stria 1 strongly shortened, present only in basal half, stria 2 nearly complete, 3rd stria present in basal half or slightly more, 4th stria present only as short basal arch, connected to base of sutural stria, 5th stria absent, sutural stria abbreviated slightly from apex, elytral disk with small secondary punctures in most of apical one-fourth, extending further anteriorly mediad 3rd stria; prosternal keel narrowly convex, strongly narrowed to subcarinate anteriorly, truncate at base, with more or less complete carinal striae weakly diverging to front; prosternal lobe very short, slightly deflexed, apical margin broadly arcuate, marginal stria more or less complete; mesoventrite truncate to very weakly produced at middle, with marginal stria complete; mesometaventral stria present, crenulate across middle, continued by inner lateral metaventral stria, extending obliquely posterad to near inner corner of metacoxa, outer lateral metaventral stria very short, present only behind mesocoxa; metaventral disk moderately coarsely punctate at sides, impunctate at middle; abdominal ventrite 1 with lateral stria strongly abbreviated posteriorly, ventrite lacking transverse anterior marginal stria, disk impunctate at middle, ventrites 2-5 with fine punctures across width; protibia narrow, lacking median and basal marginal denticles, margin straight, serrulate; mesofemur with posterior marginal stria curving anterad along apical margin; mesotibia with oblique, basal submarginal ridge; outer metatibial margin smooth; propygidium lacking basal stria, with fine ground punctation interspersed with ocellate secondary punctures mainly in basal half, propygidial gland openings evident, situated about one-fourth behind anterior margin and nearly one-third from lateral margin; pygidium with fine ground punctation, with few or no secondary punctures interspersed. Male genitalia (Figs 55E, G, J): T8 and S8 as in Baconia gibbifer   (Figs 55 A–B); T9 with dorsal plates rather broad near base, proximal apodemes reduced, short, sides uneven, narrowed strongly to apex, bearing single, inconspicuous, subapical seta on each side, ventrolateral apodemes nearly meeting at midline about one-third from apex, bluntly dentate; S9 stem narrow, strongly dorsoventrally keeled, head gradually widened to apex, apical emargination shallow and sinuate; tegmen narrower than that of Baconia gibbifer   , sides subparallel in basal half, strongly narrowed to apex, thick, strongly curved ventrad in apical half, with eversible subapical denticles ventrally; median lobe simple, about one-fifth tegmen length; basal piece one-third tegmen length.


Baconia piluliformis   is very similar to Baconia gibbifer   , above, but has its mesometaventral stria present at middle (Fig. 54G), the prosternal keel strongly narrowed to a nearly knife-like carina anteriorly, the 4th dorsal and sutural striae joined basally, the pygidium largely devoid of secondary punctures, and the anterior stria of 1st abdominal ventrite absent.


This species’ name refers to its pill-shaped form.