Baconia aeneomicans (Horn, 1873)

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini), ZooKeys 343, pp. 1-297 : 128-132

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scientific name

Baconia aeneomicans (Horn, 1873)


Baconia aeneomicans (Horn, 1873) Figs 38A39 A–C, E, I–JMap 10

Hister aeneomicans Horn, 1873: 295; Phelister aeneomicans : Schmidt 1884: 149; Baconia aeneomicans : Mazur 1984: 280.

Type locality.

UNITED STATES: District of Columbia [exact locality uncertain].

Type material.

Neotype, here designated (CMNH): “D.C.” / "Henry Ulke Beetle Coll. CMNH Acc. No. 1645 ”/” NEOTYPE Hister aeneomicans Horn, 1873, Desg. Caterino & Tishechkin, 2012". This species was originally described by Horn from "one specimen in the cabinet of Mr. Ulke, collected in the District of Columbia" (Horn, 1873: 295). Therefore there was a unique holotype at one time. The specimen was returned to Ulke, whose collection now resides in the Carnegie Museum, and mixed with other specimens with identical data. Therefore the holotype is technically lost (though probably still in existence), and a Neotype is needed. We select one of three possible specimens with identical data to the original type, the most well preserved and intact. We have not dissected this specimen to confirm sex. However, this species is morphologically uniform throughout its range and there are unlikely to be any ambiguities with its identification in the future.

Other material.

USA: 2: Florida: Leon Co., Tallahassee, 23.v.1986, FIT, H. & A. Howden (MHNG); 1: Columbia Co., O’Leno SP, 10.v.1984, M.C. Thomas (FSCA); Marion Co., Ocala, 18.vii.1977, M.C. Thomas, in fungus on log (FSCA); 1: Georgia: Baker Co., Bethany Church, 31°18.5'N, 84°36'W, 28.xii.2003, forest litter, C. W. O’Brien & R. J. Turnbow (LSAM); 1: Indiana: Parke Co., 20.vii.1962, N. Downie (FMNH); 1: Tippecanoe Co., 7.ix.1958, N. Downie (FMNH); 1: Monroe Co., Bloomington, 31. v–, blacklight trap, F.N. Young (FSCA); 2: Kansas: Jefferson Co., 1.5 km N jct. 94th St. & Kingman Rd., 39°13.38'N, 95°24.24'W,, FIT, near lower meadow, Z. Falin (SEMC); 2: 19-24.v.2005, canopy FIT, meadow, Z. Falin (SEMC); 1: 27. vi– 3.vii.2005, FIT, meadow, Z. Falin (SEMC); 3: 29. v–, FIT, meadow, Z. Falin (SEMC); 3: Louisiana: Calcasieu Par., Sam Houston Jones State Park, 30°18'N, 93°16'W, 2-31.vii.2002, FIT, A. Cline & A. Tishechkin (LSAM); 5: 31. vii– 17.ix.2002, FIT, A. Cline & A. Tishechkin (LSAM); 4: 9. iii– 16.v.2003, FIT, A. Cline & A. Tishechkin (AKTC, LSAM); 4: Catahoula Par., Sicily Island W. M. A., 30°49.5'N, 91°26'W, 10.i.2001, under bark, A. Cline & A. Tishechkin (LSAM); 1: East Baton Rouge Par., Baton Rouge, 12.ii.1982, under bark, S. M. Strother (LSAM); 1: Grant Par., 3 km SW Pollock,, FIT, H. & A. Howden & C. Scholtz (LSAM); 1: Jefferson Par., Harahan, 18.iv.1944, on small brown polypore fungus (FMNH); 1: W Feliciana Par., Feliciana Pres., nr. Freeland, 30°47'N, 91°15'W, 25. ii– 2.iii.1996, FIT, C. Carlton (LSAM); 3: 14-30.iii.1996, FIT, C. Carlton (AKTC, LSAM); 1: 18.x.1997, pines, under bark, A. Tishechkin (AKTC); 1: 10-21.x.2000, FIT, A. Cline (LSAM); 5: 1-29.iv.2001, FIT, A. Cline (LSAM); 1: 24. v–, FIT, A. Cline (LSAM); 1:, FIT, A. Cline & A. Tishechkin (LSAM); 1: 14-24.iv.2003, FIT, A. Tishechkin (LSAM); 2: 24. iv– 11.v.2003, FIT, A. Tishechkin (LSAM); 2: 11. v– 4.vii.2003, FIT, A. Tishechkin (LSAM); 1: 27. iv– 22.v.2005, FIT, A. Tishechkin & S. Gil (AKTC);, FIT, A. Tishechkin & S. Gil (AKTC); 1: 30. iii– 9.iv.2005, FIT, A. Tishechkin (AKTC); 1:, FIT, A. Tishechkin & S. Gil (AKTC); 1: W Feliciana Par., Tunica Hills W. M. A., 30°55'N, 91°30'W, 14-30.x.1998, FIT, C. Carlton & A. Tishechkin (LSAM); 1: 6-28.xi.1998, FIT, C. Carlton & A. Tishechkin (AKTC); 1: Mississippi: Tishomingo Co., 5 mi S of Burnsville T4S, R9E, Sec.2SE, 23.iv.1998, 30.iv.1998, Lindgren funnel baited with Frontalin & Loblolly Pine Turpentine, R. Tisdale (TAMU); 1: Lafayette Co., 7 mi. NW Oxford, 13.i.1986, P. Lago (FMNH); 2: Noxubee Co., N.W.R. Big Tree Trail, 33°17'17"N, 88°46'4'W, 50 m,, FIT, R. Brooks & T. Peterson (SEMC); 1: North Carolina: 1: Haywood Co., Great Smoky Mountains National Park, Purchase Knob (top), 1510 m, 35°35'4"N, 83°3'45"W, 20. vii– 12.viii.2001, FIT, C. E. Carlton (LSAM); Mecklenburg Co, Charlotte McDowell Nat. Pres., 35.08260°N, 81.013018°W, 650 ft,, UVL Trap, J. Cornell; 1: Wake Co., Raleigh, 1.xi.1964, Polyporus, J. Cornell (TAMU); 1: Oklahoma: Latimer Co., SW of Red Oak, vi.1981, K. Stephan (TAMU), 1: xii.1981, 1: vi.1982, 1: xi.1982, 2: v.1983, 9: v.1983, 1: v.1984, tree hole oak + rodent, 1: v.1984, FIT, 1: v.1984, 1: vii.1984, FIT, 1: iv.1984, 2: ix.1984, 1: iv.1985, 1: v.1985, 1: iii.1986, 2: v.1986, 1: vii.1988, 1: v.1990, 2: iv.1991, 1: v.1991, 3: vi.1992, 4: v.1993, 5: vi.1993, 1: viii.1993, 1: iv.1994, 1: v.1994, 4: v.1995, 4: vi.1995, 1: vii.1995, 4: v.1997, forest litter/FIT, 1: vi.1998 (all K. Stephan, TAMU, AKTC, FSCA); 1: Texas: Fort Bend Co., Brazos Bend St. Pk., 29. v–, FIT, buckeye-sycamore forest, B. Raber & E. Riley (TAMU); 1: Tyler Co., Kirby State Forest, 30°34'30"N, 94°25'03"W, 22. vi– 20.vii.2003, Lindgren funnel trap, E. Riley (AKTC); 3: Brazos Co., Lick Ck. Pk., College Station, 13.iv.1996, Berlese forest litter, E. Riley (TAMU, LSAM, AKTC); 1: 13-6.iv.1996, post oak-yaupon, upland forest, E. Riley (AKTC); 1: 13.iv.1996, Berlese forest litter, E. Riley (TAMU); 4: 13.iv.1996, post oak-yaupon, upland forest, E. Riley (TAMU, AKTC); 1: 25. ix– 3.i.1998, elevated FIT, bottomland forest, E. Riley (AKTC); 1: 3-11.v.1996, FIT, bottomland forest, E. Riley (AKTC); 1:, E. Riley (TAMU); 1: 9-22.iii.1997, elevated FIT, bottomland forest, E. Riley (TAMU); 5: Montgomery Co., 17.2 km N Montgomery, 17. v–, FIT, R. Anderson; 1: Wood Co., 5 mi. S Hawkins at Jct Hwy 14 & FM 2869, 6. vii– 18.viii.1996, FIT, W. Godwin (TAMU); 1: Sabine Co., 9 mi. E Hemphill,, FIT, beech-magnolia forest, R. Anderson & E. Morris (AKTC); 1: Sabine Co., Mill Creek Cove, 8.8 mi. NE Hemphill, 31.3851°N, 93.7090°W, 16. iii– 30.iii.2008, FIT-elevated, Beech Bottom, E. Riley (AKTC); 1: 25. iv– 7.v.1989, FIT, R. Anderson & E. Morris (TAMU); 1: 31. iii– 13.iv.2008, FIT, Beech Bottom, E. Riley (AKTC); 1:, FIT, beech-magnolia forest, R. Anderson & E. Morris (TAMU).

Diagnostic description.

Length: 1.4-1.7mm, width: 1.2-1.3mm; body elongate oval, subdepressed, glabrous; color metallic-blue over most of dorsum, elytra grading to green-blue in anterior half, venter rufobrunneus with faint metallic sheen; head with frons flat, ground punctation fine, sparse anteriorly, slightly coarser dorsad, frontal stria present only along inner margin of eye, obsolete across middle, supraorbital stria absent or represented by few fragments; antennal scape short, club nearly circular; epistoma faintly emarginate apically; labrum about 3 ×wider than long, weakly emarginate apically; both mandibles with strong, acute basal tooth, mesal secretory channel present; pronotum with sides subparallel in basal half, evenly rounded to apex, lateral marginal stria descending to ventral edge in posterior half, continuous anteriorly with complete anterior marginal stria, lateral submarginal stria present in basal three-fourths, pronotal disk with fine ground punctation, conspicuous secondary punctures interspersed more or less throughout, denser toward sides; elytra with one to two complete epipleural striae, outer subhumeral stria absent, inner present in basal one-third or less, dorsal striae 1-4 complete to base, progressively abbreviated apically, 4th stria arched mediad in front, stria 5 slightly abbreviated at base and apex, sutural stria present in middle one-third, abbreviated at base and apex, elytral disk with scattered secondary punctures in apical one-third; prosternum moderately broad, keel weakly emarginate at base, with carinal striae complete, separate, subparallel in basal one-fourth, weakly divergent anterad, with few punctures between; prosternal lobe slightly over one-half keel length, apical margin bluntly rounded, with marginal stria present along middle; mesoventrite weakly produced at middle, with marginal stria absent from anterior margin, present only at anterolateral corners; mesometaventral suture weakly arched forward, mesometaventral stria arched more strongly forward, rounded to subangulate at middle, continuous laterally with oblique lateral metaventral stria; metaventral disk coarsely punctate at sides, impunctate at middle; abdominal ventrite 1 with single, complete lateral stria, disk with coarse secondary punctures only laterad stria, ventrites 2-5 with sparse secondary punctures at sides, the punctures becoming almost obsolete at middle; protibia tridentate, the middle tooth closer to apical than basal, outer margin serrulate between teeth; mesotibia with two very weak marginal spines; outer metatibial margin smooth, edentate; propygidium lacking basal stria, with sparse, fine ground punctation, with coarse secondary punctures evenly interspersed, propygidial gland openings rather conspicuous, located about one-third behind anterior margin, about one-fourth width from each lateral margin, disk impunctate in immediate vicinity; pygidium with sparse ground punctation and only moderately coarser, secondary punctation denser toward base. Male genitalia (Figs 39 A–C, E, I–J): T8 narrowly, rather deeply emarginate, ventrolateral apodemes with inner apices widely separated, projecting beyond ventral midpoint, obsolete apically, apical margin shallowly emarginate; S8 with halves fused along midline, basal emargination broad, deep, basal apodemes widely separated, sides sinuately narrowed, apices obliquely truncate, densely setose, widely separated by acute apical emargination; T9 with short basal apodemes, halves nearly meeting dorsobasally, ventrolateral apodemes bluntly produced beneath, nearly to midline, apices narrowly rounded, with single seta borne on subapical tubercle on each side; T10 narrow, finely emarginate apically; S9 with long narrow, medially keeled stem, head rounded to near apex, apices subacute, apical emargination broad, sinuate; tegmen with base rather broad, weakly narrowed to apex, apices narrowly rounded, tegmen strongly curved dorsoventrally, mainly near base, with eversible subapical denticles; median lobe about one-third tegmen length, simple; basal piece about one-third tegmen length.


Baconia aeneomicans is among the very few metallic species in this species group (Fig. 38A), and this in combination with its distribution makes its identification straightforward. It is sympatric with only two other North American Baconia species, Baconia venusta , which is much larger, with a larger, more convex, less distinctly punctate body (Figs 11 C–F; in addition to lacking all the characters of the Baconia aeneomicans group in general), and Baconia stephani sp. n., described below. The latter is rather similar, but may be easily separated by its non-metallic coloration, more narrowly elongate body, and more coarsely and completely punctate pronotum.