Baconia angusta Schmidt, 1893

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297 : 109-112

Baconia angusta Schmidt, 1893 Figs 32 A–B33A–FMap 9

Baconia angusta Schmidt, 1893a: 11; Phelister angustus : Lewis 1901: 372; Baconia angusta : Mazur 1997: 25.

Type locality.

BRAZIL [exact locality unknown].

Type material.

Lectotype male, here designated (ZMHB): “Brasilia” / “Type” / "Baconia angusta Schmidt, 1893. ex. Coll. Schmidt-Bickhardt" / "LECTOTYPE Baconia angusta Schmidt, 1893, M.S.Caterino & A.K.Tishechkin des. 2010" (ZMHB). Paralectotype: “Havana” / “Type” / "angusta M." / "angustus Schm" / "Coll. J. Schmidt" / "Baconia angusta Schmidt, 1893. ex. Coll. Schmidt-Bickhardt"/ "PARALECTOTYPE Baconia angusta Schmidt, 1893, M.S.Caterino & A.K.Tishechkin des. 2010" (ZMHB). This species was described from an unspecified number of specimens, and the lectotype designation fixes primary type status on one of two original specimens.

Other material.

BRAZIL: 6: Bahia (BMNH); 1: Paraná: Parque Estad. Guartelá, Mpio. Tibagi, 24.5663°S, 50.2570°W, 12-15.xii.2011, FIT, forest, M. Caterino & A. Tishechkin, DNA Extract MSC-2277, EXO-00931 (MSCC).

Diagnostic description.

Length: 1.3-1.8mm, width: 0.9-1.3mm; body elongate, parallel-sided, depressed, glabrous; color rufescent, shining; head with frons elevated over antennal bases, slightly depressed at middle, interocular margins convergent dorsad, frontal punctation sparse, diminished in anterior half, frontal stria absent, supraorbital stria vaguely indicated by serial punctures; antennal scape short, club rounded, slightly expanded apically; epistoma flat, apex weakly emarginate; labrum about 3 × wider than long, apical margin weakly emarginate; mandibles short, each with median tooth; pronotum with sides subparallel in basal half, rounded to apex, lateral marginal and lateral submarginal striae very close throughout, the submarginal stria ending freely near anterior corner, marginal stria continuous along anterior margin; pronotal disk narrowly depressed along anterolateral margin, ground punctation fine, small secondary punctures rather well-impressed in lateral fourth; elytra with two more or less complete epipleural striae, outer and inner subhumeral striae absent, dorsal stria 1 nearly complete, fine, scratchlike in apical third, striae 2-4 progressively more abbreviated apically, basal arch of 4th subangulate, meeting base of sutural stria, 5th stria absent, sutural stria obsolete in apical fourth, elytral disk with small, shallow secondary punctures in apical fourth; prosternal keel weakly convex between striae, shallowly emarginate at base, carinal striae weakly divergent basally and apically; prosternal lobe about one-half keel length, apical margin rounded, marginal stria obsolete at sides; mesoventrite produced at middle, marginal stria complete; mesometaventral stria weakly arched forward, crenulate, continued by inner lateral metaventral stria obliquely posterad toward middle of metacoxa, outer lateral metaventral stria very short to absent; metaventral disk impunctate at middle; abdominal ventrite 1 with inner lateral stria complete, outer lateral stria present as short postcoxal fragment, disk impunctate at middle, ventrites 2-5 finely, sparsely punctate across middle; protibia with four weak marginal denticles more or less evenly spaced, margin serrulate between; mesofemur with posterior marginal stria continuous around distal margin; mesotibia with two distinct marginal spines; outer metatibial margin smooth; propygidium lacking basal stria, with moderately large ocellate punctures separated by slightly less than their diameters, propygidial gland openings present nearly one-half behind anterior margin, surrounded by small impuncate area; pygidium with fine ground punctation rather dense, small secondary punctures throughout, slightly sparser toward apex. Male genitalia (Figs 33 A–F): T8 subquadrate, about as long as broad, weakly narrowed to apex, basal emargination shallow, basal rim moderately well-sclerotized, apex very shallowly, broadly emarginate, ventrolateral apodemes extending nearly to longitudinal midline, inner apices separated by one-eighth T8 width; S8 divided, slightly shorter than T8, flat, inner margins approximate at base, divergent apically, outer margins weakly rounded, convergent, apical guides undeveloped, apical velar membrane absent, apex with numerous conspicuous setae; T9 with basal apodemes stout, nearly one-half total length, dorsal lobe of T9 broad, subquadrate, bearing few (~2) conspicuous setae, ventrolateral apodemes sinuate along inner edge, with blunt subapical tooth; S9 broad, stem absent, basal margin semicircular, sclerotized along basal margin and extending distad along midline, apex with blunt central process, and complex, curving digitform processes on either side; tegmen very short and broad, sides straight and subparallel in basal two-thirds, convergent to wide, truncate apex, with inner apical sclerotizations of uncertain function, tegmen in lateral aspect widest at middle, apical half broadly excavate beneath; median lobe with diverging proximal apodemes, about one-third tegmen length; basal piece long, wide, about two-thirds tegmen length.

Remarks.

Externally, Baconia angusta is moderately distinctive in this group, being the smallest and most distinctly depressed (Figs 32 A–B) yet known. However, its genitalia are highly distinct, with a very short, broad aedeagus with a long basal piece, an almost semicircular spiculum gastrale with unique digitiform apical processes, and a 9th tergite with complex, bluntly dentate ventromedial lobe

The type locality of this species is unclear. In the original description Schmidt mentions "Hab. Havana, Brasilia". First of all it is apparent that this corresponds to two distinct localities (corresponding to the two syntypes we found.) Although Mazur (1984, 1997) cites only Brazil for the species’ distribution, we can find no record of a Havana in Brazil. It conceivably refers to Havana, Cuba, but this would be well outside the known distribution for this entire group of species. Because of this doubt, and the fact that the Havana specimen is female, we selected the Brasilia specimen as the lectotype. At the same time, Brasilia probably refers only to the country in general, as the city of Brasilia had not been founded at the time of description.