Hydraena flagella, new species Figs. 138 (habitus), 140 (aedeagus), 190 (spermatheca), 202 (map) Type Material. Holotype (male): Paraguay: Dep. Guaira, Mbocayaty, Arroyo Gervasio, 4 xi 1995, Drechsel. Deposited in the NMW. Paratypes: Same data as holotype (2 NMW). Differential Diagnosis. A strongly shining species, with dorsal punctation very fine and sparse; the punctures on the pronotal disc are smaller than the largest punctures on the frons, an unusual condition. The elytra are unusual in that the punctures become slightly coarser posteriorly, and many of the punctures on the disc are random or only subserial. Similar in dorsal habitus to H. jivaro Perkins (Figs. 102, 138); differentiated therefrom by the slightly finer pronotal punctation, the greater degree of randomness of the basal elytral punctures, the narrower P2, and the differently shaped plaques (arcuate and larger in H. flagella). The aedeagi of the two species are similar in the presence of a long gonopore-bearing flagellum, the presence of long setae on the dorsal surface, and general shape, but markedly differ in many details (Figs. 105, 140). Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.57/0.67; head 0.22/0.36; pronotum 0.42/0.52, PA 0.42, PB 0.46; elytra 0.93/0.67. Dorsum of head dark brown to piceous; pronotum testaceous in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 7/14/7; elytra dark brown; legs light brown; maxillary palpi testaceous, tip not darker. Frons punctures ca. 0.5xef, not larger, but slightly denser near eyes than medially; interstices strongly shining, ca. 1.5–2xpd laterally, 3–7xpd medially. Clypeus microreticulate, dull laterally, very strongly shining and very finely sparsely punctulate, or impunctulate, medially. Mentum very sparsely very finely punctulate, weakly shining; postmentum very finely densely micropunctulate in median concavity, surrounding areas smooth, shining. Genae raised, shining, without posterior ridge. Pronotum moderately arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent, but this area virtually impunctate; punctation very fine and very sparse, punctures on disc smaller than largest punctures of frons, interstices strongly shining, ca. 4–10xpd, punctures larger and denser at anterior and posterior; PF1 absent; PF2 extremely shallow, almost imperceptible; PF3 deep; PF4 very shallow or obsolete. Elytra moderately convex, weakly arcuate laterally; summit of posterior declivity at ca. posterior 1/3; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming slightly coarser toward posterior, many punctures on disc random or subserial. Intervals not raised, shining, on basal 1/3 ca. 2–5xpd, as are interstices between punctures of a row. Apices in dorsal aspect truncate or subtruncate, in posterior aspect margins forming strong angle with one another. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/2/8/5. P1 laminate; median carina sinuate in profile. P2 narrow, l/w ca. 5/1, sides parallel or slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques large, wide in posterior 1/2, tapering to point anteriorly, arcuate, converging toward one another anteriorly, weakly raised, located at sides of deep median depression. Metaventrite with very small point on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 4x P2. Profemur (male) with small, sharply pointed tubercle on medial margin near trochanter. Protibia straight, gradually, moderately increasing in width from base to subapically, then excavate to apex. Mesotibia straight, slen- der. Metatrochanter with very small tubercle. Metatibia slender, straight. Abdominal apex slightly asymmetrical; last tergite cap-like, with very small apicomedian notch. Female (microslide mount, n=1): last tergite sharply rounded, without apicomedian notch, setae long, not hooked, ca. 18 on each side of median gap; gonocoxite not midlongitudinally divided, apical margin emarginate between sensilla clusters, no transverse ridge evident at bor- der of microreticulation; spermatheca type C1, accessory gland cup partial. Etymology. Named in reference to the large aedeagal flagellum. Distribution. Currently known only from the type locality (Fig. 202). Notes. The aedeagus of H. flagella (Fig. 140) has three long setae on the dorsal surface, perhaps indicating that this species is related to those in the Jivaro Complex.

Published as part of Perkins, Philip D., 2011, New records and description of fifty-four new species of aquatic beetles in the genus Hydraena Kugelann from South America (Coleoptera: Hydraenidae), pp. 1-198 in Zootaxa 3074 on pages 65-66, DOI: 10.5281/zenodo.1050060