Operclipygus latemarginatus (Bickhardt, 1920) Bickhardt, 1920

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini), ZooKeys 271, pp. 1-401 : 197-198

Operclipygus latemarginatus (Bickhardt, 1920) comb. n. Figs 52 A–E53C–DMap 18

Pseudister latemarginatus Bickhardt, 1920: 237.

Pseudister laterimarginatus : Mazur (1997, misspelling).

Type locality.

Not specified beyondBuenos Aires Province, Argentina.

Type material.

Lectotype, here designated (ZMHB): "Rep. Argentina. Prov. Buenos Aires, 17.X.1909, C. Bruch" / "LECTOTYPE Pseudister latemarginatus Bickhardt, 1920 M.S.Caterino & A.K.Tishechkin des. 2010". There should also be a syntype in Argentina, which we were not able to borrow but should nonetheless henceforth be considered a paralectotype. This species was described from an unspecified number of specimens, and the lectotype designation fixes primary type status on one of the known syntypes.

Other material.

BRAZIL: Minas Gerais: 1: Ingaí, Univ. Fed. Lavras, Lavras, 21°14'S, 45°00'W, ix.2001, FIT, dry forest, F.Z. Vaz-de-Mello (CEMT); Paraná: 1: Tibagi, Parque Estad. Guartelá, 24.5663°S, 50.2570°W, 12-15.xii.2011, FIT, forest, M.S. Caterino & A.K. Tishechkin, DNA Extract MSC-2276 (SBMNH); 1: Campina Grande do Sul, Estrada de Mandacaia, 26.xii.2008, FIT, F.W.T. Leivas (UFPR); Rio de Janeiro: 1: Nova Friburgo, 22°16'S, 42°32'W, 26-31.x.2009, FIT (CHND).

Diagnostic description.

Length: 2.62-2.96 mm, width: 2.25-2.37 mm; body rufopiceous, subquadrate, depressed; frons prominent, transversely elevated between antennal bases but depressed at middle, frontal stria varied, broadly interrupted at middle in lectotype, fine fragments visible nearer the sides, complete, sinuate in all other specimens; labrum wide, one-third as long as wide, slightly emarginate anteriorly; left mandible with weak, blunt basal tooth, right mandible with small subacute tooth; antennal club with basal and middle annuli complete, transverse; pronotal disk with prescutellar impression narrow, distinct, as long or slightly longer than scutellum, with few larger punctures at sides; marginal pronotal stria fine, complete or interrupted behind head; submarginal stria continuous along lateral and anterior margins, may be sinuous at sides, with bead wider anteriorly (as in lectotype); anterior pronotal gland openings close together, somewhat posterolaterad eye; elytron with outer subhumeral stria briefly interrupted at middle but complete to apex, variably abbreviated at base, inner subhumeral stria absent, striae 1-3 complete, 4th stria present in apical two-thirds or less, 5th stria present in apical third or less, sutural stria present in apical two-thirds; prosternal keel weakly produced at base, carinal striae straight, convergent and connected anteriorly and posteriorly; prosternal lobe with complete marginal stria; anterior margin of mesoventrite broadly emarginate; mar ginal mesoventral stria very fine and barely interrupted at middle; displaced by anteriorly arcuate mesometaventral stria; lateral metaventral stria extending toward middle of metacoxa; 1st abdominal ventrite with single lateral stria abbreviated apically, disk with few fine punctures along posterior margin; propygidium covered with small, shallow punctures separated by a little less than their diameters, slightly smaller and sparser posteriorly; pygidial punctures finer and sparser, with inconspicuous ground punctation; both propygidium and pygidium with transverse waves of microsculpture; marginal pygidial sulcus present around apical third of margin, fine but distinct, obsolete basally. Male genitalia (Fig. 52): accessory sclerites present; T8 with sides subparallel in basal two-thirds, faintly desclerotized at apicolateral angle, convergent to apex, with rather deep, narrow basal emargination, basal membrane attachment line distad basal emargination by about one-third its depth, apical emargination very narrow, ventrolateral apodemes symmetrical, widely separated basally; S8 rather short, sides subparallel, narrowed at middle, apices bluntly rounded, ventral halves approximate just at base, slightly diverging to apex, apical guides evenly developed from base to apex; T9 with sides subparallel in basal third, convergent to narrow, weakly opposing apices; T10 completely divided; S9 narrowest near apex, with sclerotized, elevated midline, weakly widened to subtruncate base, apex minutely emarginate, apical flanges separate, extending up onto lateral flanges; tegmen widest near base, narrowed fairly evenly to apex, apex evenly curved ventrad in apical half, medioventral process narrowly ‘U’ -shaped, projecting beneath about one-fourth from base; basal piece about one-third tegmen length; median lobe about one-third tegmen length, with proximal apodemes thin, undifferntiated.

Remarks.

This species is placed in the Operclipygus farctus group mainly on the basis of the position of the pronotal gland openings, close together along the anterior margin, and it is in some respects similar to the preceding two species, mostly in body shape, projecting prosternal keel, and pygidial punctation. However, it differs in a number of other characters, including frontal shape and striae(Fig. 53D), pronotal striae(Fig. 53C), presence of prescutellar impression, and most significantly, in having the annuli of the antennal club complete and straight/transverse. The apicolaterally desclerotized T8(Fig. 52A) on the other hand, is quite similar to that of several members of this group. Its position will require careful evaluation in future analyses. Specimens more or less corresponding to this species are known from a few localities in Minas Gerais, Paraná and Rio de Janeiro, Brazil. However, these lack the typically (or aberrantly?) sinuate submarginal pronotal stria. We consider them provisionally conspecific, but more material is needed. Bickhardt (1920) noted that the type was collected from the nest of Ctenomys Blainville (Rodentia: Ctenomyidae ), or tuco-tuco, and Bruch (1937) provided a few additional details on the type collection.