Hydraena atroscintilla, 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 : 35-36

Hydraena atroscintilla , new species

Figs. 53 (habitus), 55 (aedeagus), 176 (spermatheca), 197 (map)

Type Material. Holotype (male): Ecuador: Pichincha, Nono, 15.1 km NW, ex. flight intercept trap, elev. 2000 m, 0° 1' S, 39° 19' W, 24–26 x 1999, Z. H. Falin ( ECU 1F99 022). Deposited in the SEMC. Paratype: Same data as holotype (1 SEMC).

Differential Diagnosis. A medium sized species with the entire dorsum very darkly colored, dark brown to piceous. The dorsal punctation is not coarse but is rather dense; the interstices are ca. 2–4xpd on the frons, 1–3xpd on the pronotal disc, and ca. 1.5–2xpd on the elytra. Somewhat similar in dorsal habitus and ventral structure to H. peckorum ( Figs. 53 , 56 ); differentiated therefrom by the less angulate sides of pronotum, the shallower PF2, and the narrower explanate margin of the elytra. The unusual aedeagus cannot be confused with any other known American Hydraena , but perhaps shows some similarity in basic plan to that of H. peckorum ( Figs. 55, 58). In both species the female last tergite has non-hooked setae.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.70; head 0.26/0.39; pronotum 0.39/0.55, PA 0.43, PB 0.48; elytra 1.03/0.70. Dorsum dark brown to piceous; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 0.5–1xef, not appreciably larger or denser near eyes than medially; interstices shining, ca. 2–4xpd. Clypeus microreticulate laterally, very finely sparsely punctulate and strongly shining medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge.

Pronotum moderately arcuate laterally; anterior margin straight behind eyes, emarginate behind frons except slightly produced at very small scintilla; punctures on disc larger and deeper than those on frons, interstices shining, 1–3xpd on disc, punctures slightly denser at anterior and posterior; PF1 absent; PF2 very shallow, almost imperceptible; PF3 moderately deep; PF4 absent.

Elytra weakly arcuate laterally; summit of posterior declivity slightly before midlength; lateral explanate margins narrow; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming slightly smaller and more widely spaced toward posterior. Intervals not raised, shining, on basal 1/3 ca. 1.5–2xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1.5/6/4. P1 laminate; median carina sinuate in profile. P2 narrow, l/w ca. 3/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight, slightly 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. 2x P2. Protibia slightly arcuate, gradually increasing in width from base to subapically, then narrowed slightly. Mesotibia slender, straight. Metatibia slender, straight, medial margin with sparse row of overlapping, recumbent setae. Male abdominal apex slightly asymmetrical; last tergite with large notch, offset to left side. Female (microslide mount, n=1): last tergite broadly rounded, with rather deep apicomedian notch, setae long, hair-like, not hooked; gonocoxite not midlongitudinally divided, apical margin sharply rounded, no transverse ridge evident at border of microreticulation; spermatheca type C2. Etymology. Named in reference to the black dorsal color, and the pronotal scintilla.

Distribution. Currently known only from the type locality ( Fig. 197).

Figures

FIGURE 53. Hydraena atroscintilla, holotype, dorsal and lateral habitus, and venter.

FIGURE 56. Hydraena peckorum, holotype, dorsal and lateral habitus, and venter.