Operclipygus impunctipennis (Hinton, 1935) Hinton, 1935

Caterino, Michael S. & Tishechkin, Alexey K., 2013, A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini), ZooKeys 271, pp. 1-401 : 263-265

Operclipygus impunctipennis (Hinton, 1935) comb. n. Figs 69 A–B70A–C, E, HMap 25

Phelister impunctipennis Hinton, 1935b: 58.

Type locality.

MEXICO: Tabasco: Teapa [17°33'N, 92°57'W].

Type material.

Holotype: "Teapa, Tabasco, Feb. H.H. Smith" / " Phelister impunctipennis Hntn." (BMNH), examined 2010.

Other material.

BELIZE: Cayo: 1: San Pastor, 27.x.1994, FIT (BMNH). MEXICO: Chiapas: 1: "Encinar 16 de septiembre" Carretera Tuxtla Gtz.-Chicoasen Loc. Cn., 16°48'60"N, 93°10'43"W, 851m, 22.iii.2005, cow dung (ECOSUR), 1: 17.iii.2005, cow dung (ECOSUR), 1: 26.iii.2005, cow dung (ECOSUR), 2: 25.v.2005, dead rat bait (ECOSUR); 1: Palenque, 100m, 2-30.vii.1983, FIT, S. & J. Peck & R. Anderson (CHSM); 1: 8km S Chicoasen, 690m, 1.vi.1991, sifted from leaf litter, J. Ashe (CHSM);' 1: Salto de Agua, 8km SE, 17.51592°N, 92.30231°W, 100m, 14.vi.2008, sifted leaf litter, secondary wet forest (SEMC); 4: Parque Nac. Sumidero, 1000m, 25.v.1990, FIT, H. & A. Howden (AKTC, BDGC), 1: 13.vi.1990, FIT, H. & A. Howden (BDGC), 1: 1-14.vi.1990, FIT, H. & A. Howden (BDGC); 3: San Luis Potosí, 13km E Xilitla, 335m, 4.vi.1987, berl. trop. for litter, R. Anderson (SEMC); 1: 50mi. NNW Cd. Valles El Salto, 6.vii.1969, tropical decid. forest leaf litter, S. & J. Peck (FMNH).

Diagnostic description.

Length: 1.72-1.87 mm, width: 1.47-1.59 mm; body rufopiceous, elongate oval, smooth, shining; frons weakly depressed at middle, with sparse but fairly conspicuous ground punctation; frontal stria weakly rounded between eyes, complete across front; supraorbital stria absent; epistoma mostly convex; labrum about twice as wide as long, apically emarginate on dorsal part of edge, but with apical process beneath, just left of midline; left mandible lacking basal tooth, right mandible with small subacute tooth; pronotal disk with prescutellar impression lacking or extremely fine, punctiform, ground punctation very fine and inconspicuous, with ~10 coarse lateral punctures; marginal pronotal stria complete behind head and along lateral margins; lateral submarginal stria complete to variably basally abbreviated along side, arched inward anteriorly, nearly meeting anterior portion, which is recurved posterad about one-fifth pronotal length; median pronotal gland openings situated behind recurved ends of anterior stria, about two-thirds pronotal length from anterior margin; elytron with two complete epipleural striae, outer subhumeral stria very short and apical, inner subhumeral absent, striae 1-2 complete, 3rd stria very finely impressed in basal third (rarely reaching the anterior elytral margin), and as a very short apical stria, 4th stria complete, 5th stria present as basal rudiment or absent, sutural stria present in apical two-thirds; elytral disk with apical row of conspicuous punctures; prosternal lobe weakly emarginate basally, carinal striae complete, widely separate at base, convergent at middle, weakly divergent to apical arch; prosternal lobe with complete marginal stria; mesoventrite weakly projecting at middle, marginal stria barely interrupted; mesometaventral stria evenly and strongly arched forward to near anterior mesoventral margin; lateral metaventral stria extending to inner third of metacoxa; metaventral disk convex; 1st abdominal ventrite with single lateral stria present, longitudinal in basal half, interrupted near inner corner of metacoxa, continuing directly laterad behind coxa, passing through a small but distinct postcoxal fovea; propygidium with ground punctation fine, with moderately large punctures separated by slightly less than their diameters in basal half, frequently coalesced into short strioles in ante rolateral corners, becoming smaller and sparser toward apex, more or less absent from apical third; pygidium with ground punctation fine, sparse, slightly coarser punctures often interspersed, separated by 4 –5× their diameters; marginal pygidial stria very fine, present only apically, occasionally absent. Male genitalia (Figs 70 A–C, E, H): accessory sclerites present; T8 elongate, sides subparallel in basal half, angulate to narrow apex, basal emargination broad and deep, nearly reaching basal membrane attachment line; S8 with sides convergent to apex, with apical guides narrow along most of margin, expanded near acuminate apex, inner edges approximate near base, weakly divergent to near apex; T9 with sides subparallel in basal half, convergent toward narrow, subacute apex; T10 with halves separate; S9 narrowest near apex, with base of stem slightly wider, subparallel to rounded base, apex narrowly emarginate, rounded, with strongly produced basolateral corners, apical flange divided; tegmen rather flat, with sides evenly rounded from base to apex, curving ventrad, medioventral process not at all evident; basal piece about one-third tegmen length; median lobe just over half tegmen length, proximal apodemes differentiated into similar-length thick and filamentous portions.

Remarks.

The pronotal striae (Fig. 69A) would tend to place this species in the Operclipygus hamistrius group. However, the darker coloration, lack of microsculpture on the integument, pattern of elytral striation, and the very distinct male genitalia exclude it from that group. Among related species, Operclipygus impunctipennis may be distinguished by the pronotal striae, in part. Most other species in this group have the submarginal stria unbroken across the front. This, together with the unusual pattern of elytral striae, the third being broadly interrupted but with the fourth complete, will distinguish it from nearly any other Operclipygus .