Baconia eximia (Lewis, 1888)

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297: 76-78

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Baconia eximia (Lewis, 1888)


Baconia eximia (Lewis, 1888)   Figs 18 C–D19E–F, H, K, O–PMap 5

Phelister eximius   Lewis, 1888: 191; Baconia eximia   : Mazur 1984: 280.

Type locality.

NICARAGUA: Chontales [exact locality uncertain].

Type material.

Holotype, sex undetermined (BMNH): "Chontales. Janson" / "Sp. figured" / "eximius Lewis Type" / "B.C.A.,Col.,II,(1). Phelister". This species was explicitly described from a single specimen.

Other material.

BELIZE, 1: Cayo: Las Cuevas Res. Sta., 16°44.33'N, 88°59.07'W, 550 m, 28.v.2000, FIT, M. Caterino, DNA Extract MSC-0065, EXO-01142; 1: Orange Walk: Rio Bravo Cons. Area, 25-30.iv.1996, FIT, C.E. Carlton (CHPWK). GUATEMALA: 2: Zacapa: Santa Clara, in interior valley of Sierra de las Minas (N. of Cabanas), 5500 ft, 9.viii.1948, under bark, R. Mitchell (FMNH); 1: Santa Cruz, Marble Quarry rd, NE Teculutan, 15°04.454'N, 89°41.074'W, 1539m, 17.v.2006, R.S. Zack (WSUC). MEXICO: 1: Veracruz: 15 mi W Tlapacoyan, 28.ii.1972, F. Parker & D. Miller (CHND); 1: Quintana Roo: Chetumal, 24.x.2004, M. Sawoniewicz (MHNG), 1: 30.x.2004, M. Sawoniewicz (MHNG). NICARAGUA, 1: Granada: Res. Nat. Volcan Mombacho, entrance rd, 11°50.05'N, 85°58.83'W, 910 m,, FIT, R. Brooks, Z. Falin & S. Chatzimanolis (SEMC); 1: Rio San Juan: Ref. Bartola, 8 km SE El Castillo , 10°58.6'N, 84°20.4'W, 30 m, 25-31.v.2002, FIT, rainforest, S. Peck (CMNC). PANAMA:1: Colón: P. N. San Lorenzo, Achiote, Cafetal A Dist. , 9°12'N, 79°58'W, 10 m, 12-26.v.2008, FIT, A. Mercado (AKTC); 1: P. N. San Lorenzo, Achiote, Pastizal B Dist., 9°12'N, 79°59'W, 0 m, 12-27.v.2008, FIT, A. Mercado (GBFM); 1: Barro Colorado Island, 9°10'N, 79°50'W, 15-27.v.1972, T. & L. Erwin (CHND); 1: Barro Colorado Island, 9°11'N, 79°51'W, 15.vii.1994, FIT, D. Banks (SEMC), 1: 1-10.viii.2005, J. McHugh, DNA Extract MSC-1901, EXO-00431, 1: 1-10.viii.2005, J. McHugh, N. Nguyen & C. Rodriguez (MSCC), 1: 14.vii.1969, in rotting fruit, W. Overal (FMNH).

Diagnostic description.

Length: 2.2-2.6mm, width: 2.2-2.3mm; body elongate oval, weakly depressed, glabrous; dorsum metallic blue, head and pronotum greenish-blue, contrasting slightly with elytra; frons transversely elevated between antennal bases, weakly depressed behind, interocular margins strongly convergent dorsad, ground punctation fine, with few secondary punctures near vertex, frontal stria present along inner margin of eye, interrupted over antennal bases, but complete across middle, supraorbital stria absent; antennal scape short, club broadly rounded; epistoma weakly concave below frontal ridge, apical margin truncate to weakly emarginate; labrum about 3 ×wider than long, weakly emarginate apically; both mandibles with acute basal tooth; pronotal sides weakly convergent in basal half, somewhat abruptly arcuate to apex, weakly depressed in anterior corners, marginal stria complete along lateral and anterior margins, lateral submarginal stria absent, ground punctation of pronotal disk very fine, interspersed with small secondary punctures in lateral third; elytra with three complete epipleural striae, outer subhumeral stria absent, inner subhumeral stria present in basal fourth, dorsal striae 1-3 complete, 4th stria variably abbreviated from apex, occasionally absent, 5th stria absent, sutural stria present in about apical three-fourths, elytral disk with few coarse punctures in apical fourth; prosternum moderately broad, weakly convex, keel very weakly emarginate at base, carinal striae complete, divergent anterad and posterad, separate throughout; prosternal lobe rather short, about one-half keel length, apical margin broadly rounded, marginal stria deeply impressed at middle, fragmented at sides; mesoventrite weakly produced at middle, marginal stria interrupted, mesometaventral stria absent; lateral metaventral stria extending from near mesocoxa posterolaterad toward middle of metacoxa, slightly abbreviated, sinuate apically, outer lateral metaventral stria short, oblique, metaventral disk impunctate at middle; abdominal ventrite 1 with single lateral stria abbreviated apically, middle portion of disk impunctate; protibia weakly 4-5 dentate, outer margin serrulate between teeth; mesotibia with two weak marginal spines; outer metatibial margin smooth; propy gidium without basal stria, discal punctures rather small, ocellate, denser in basal half; propygidial gland openings evident about one-fourth from anterior margin, one-third from lateral margins; pygidium with fine ground punctation uniformly interspersed with small secondary punctures. Male genitalia (Figs 19 E–F, H, K, O–P): T8 slightly longer than broad, sides subparallel, more or less straight, basal emargination shallowly rounded, apical emargination shallow, narrow, subacute, 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 membraneous apical velum bearing a fine but dense setal fringe, apical guides weakly developed, widest near apex; T9 with basal apodemes moderately thick, about one-third total T9 length, apices bent mediad, narrowly rounded, glabrous, ventrolateral apodemes weakly produced beneath; S9 stem parallel-sided in basal two-thirds, expanded abruptly, then more gradually to narrow, subquadrate, divergent apices, more strongly sclerotized in apical half, apical margin shallowly divided; tegmen long, narrow, widest near apex, in lateral aspect slightly thickened in apical half, very weakly curved over entire length; median lobe about one-third tegmen length; basal piece about one-third tegmen length.


Among those few Baconia godmani   group species having the halves of the male 8th sternite fused, Baconia eximia   can be recognized by its distinctive, more or less complete transverse frontal elevation (Fig. 18D). Other helpful characters include the 4th elytral stria being abbreviated from apex (Fig. 18C) and the absence of the mesometaventral stria. There is some evident variation among known specimens, with those from Nicaragua showing much finer propygidial and pygidial punctation.