Hydraena novacula, Perkins, Philip D., 2011

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), Zootaxa 3074, pp. 1-198 : 68-69

Hydraena novacula , new species

Figs. 146 (habitus), 147 (aedeagus), 203 (map)

Type Material. Holotype (male): Peru : Cuzco, Buenos Aires (at km 132), elev. 2150 m, 13° 8' S, 71° 33' W, 29 viii 1989, R. A. Faitoute (colln. 5). Deposited in the USNM.

Differential Diagnosis. A moderately broad species with an indistinct pronotal fascia. The pronotum is rather transverse and wider basally than apically (PA/PB ca. 0.40/0.47), and the disc is finely sparsely punctate, punctures smaller than the largest frons punctures. The male protibiae are distinctively modified. This species is not easily compared to any others, both in dorsal habitus ( Fig. 146 ) and male genitalia. The aedeagus ( Fig. 147) is unlike any other known American Hydraena .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.56/0.68; head 0.23/0.36; pronotum 0.36/0.49, PA 0.40, PB 0.47; elytra 0.97/0.68. Dorsum of head piceous; pronotum dark brown in front of and behind diffusely margined, indistinct piceous fascia, ratios of color bands, as measured in midline, ca. 7/12/4; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1.5xef, larger and much denser near eyes than medially; interstices shining, ca. 1xpd laterally, 3–8xpd medially, midline nearly impunctate. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum and postmentum very sparsely very finely punctulate, strongly shining. Genae raised, shining, without posterior ridge.

Pronotum weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; punctures very fine on disc, much smaller than largest punctures on frons, interstices shining, ca. 3–7xpd medially, punctures slightly larger and denser at anterior and posterior, basal punctures distinctly larger laterally than medially; PF1, PF2 and PF4 absent; PF3 moderately deep.

Elytra moderately convex, weakly arcuate laterally; summit of posterior declivity slightly before midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, shining, on basal 1/3 ca. 2–3xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming moderate angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/1/5/5. P1 laminate; median carina sinuate in profile. P2 l/ w ca. 5/3, sides parallel or very slightly diverging toward blunt apex, apex raised conjointly with raised mesoventral intercoxal process. Plaques narrow, straight, slightly converging toward one another anteriorly, very weakly raised, located at sides of median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 1.5x P2. Protibia distinctively widened on medial margin at distal 2/3, then emarginate to apex, few short spines in emargination. Meso- and metatibia slender, straight. Abdominal apex symmetrical; last tergite with apicomedian notch.

Etymology. Named in reference to the blade-shaped process of the aedeagus.

Distribution. Currently known only from the type locality ( Fig. 203).

Figures

FIGURE 146. Hydraena novacula, holotype, dorsal and lateral habitus, and venter.