Operclipygus arquus Caterino & Tishechkin 2013

Length: 2.03–2.12 mm, width: 1.62–1.75 mm; body rufescent, ovoid, sides rounded; frons depressed at middle, prominent over antennae; frontal stria rounded at sides, broadly interrupted in most, with occasional median fragments present; labrum about 2.5× as wide as long, very weakly emarginate apically; pronotum with ground punctation fine and sparse with few, ~6-8 coarse lateral punctures, prescutellar region slightly depressed, but lacking distinct fovea; marginal pronotal stria not descending to hypomeron; pronotum with complete lateral submarginal stria close to margin, lateral margin slightly sinuate toward base; anterior submarginal stria detached, forming more or less continuous arc across front of pronotum, reaching back one-fourth to one-third pronotal length; elytra with outer subhumeral stria present in apical half or less, inner subhumeral stria absent, striae 1-4 very fine but complete, 4th often fragmented toward base, 5th stria present in apical third, sutural stria present in apical half; venter with faint microsculpture almost throughout, effaced on swelling of metaventrite; prosternum, mesoventrite, and anterior half of metaventrite depressed (female with depression of metaventrite less distinct); prosternal keel weakly emarginate at base, with complete carinal striae rather widely separated to near apex; prosternal lobe with weak swelling at center of base; mesoventrite very weakly projecting at middle, with marginal stria broadly interrupted; mesometaventral stria strongly arched forward to near mesoventral margin; metaventrite markedly convex in middle of basal half (in both sexes); lateral metaventral stria extending toward outer corner of metacoxa, but generally abbreviated just behind middle; 1st abdominal ventrite with two strongly abbreviated lateral striae; propygidium and pygidium both with conspicuous transverse microsculpture; propygidium with sparse, moderately large punctures mainly in basal half; male especially with anterior half of pygidium simply, finely sparsely punctate, females with coarser pygidial punctures; fine apical marginal stria present only in apical half. Male genitalia very similar to those of Operclipygus hamistrius (see Figs 57A–D), differing as follows: T8 with sides subparallel; S8 shorter, with apices bluntly subacuminate, ventral creases conspicuous; tegmen (Fig. 57K) shorter, widest distinctly basad middle, with sides rounded, not as strongly narrowed to apex; indistinguishable from that of Operclipygus pichinchensis.