Hydraena buscintilla, 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 : 25-26

Hydraena buscintilla , new species

Figs. 27 (habitus), 29 (aedeagus), 195 (map)

Type Material. Holotype (male): Suriname: Sipaliwini District, Camp 3, Wehepai; 2010 CI-RAP Survey, detrital pools forest, elev. 237 m, 2° 21.776' N, 56° 41.861' W, 3–7 ix 2010, Short & Kadosoe (SR10-0903-02A). Deposited in the SEMC.

Differential Diagnosis. Similar in dorsal habitus to H. mintrita ( Figs. 27 , 31 ); differing therefrom in larger size (ca. 1.51 vs. 1.36 mm), slightly differently shaped pronotum, and a more distinctly margined pronotal macula. The aedeagi of the two species differ markedly, and should be examined for reliable identifications ( Figs. 29, 33). The aedeagus of H. buscintilla is more similar to that of H. costiniceps ( Fig. 25), but the two distinctively differ in many details.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.51/0.62; head 0.24/0.37; pronotum 0.38/0.51, PA 0.41, PB 0.45; elytra 0.90/0.62. Dorsum of head dark brown to piceous; pronotum testaceous around dark brown, subrectangular macula, area between macula and lateral margin slightly darker than surrounding testaceous area, ratios of color bands, as measured in midline, ca. 7/12/5; elytra dark brown; legs light brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1–1.5xef, slightly larger and denser near eyes than medially; interstices laterally microreticulate, dull, medially shining, ca. narrow walls to 1xpd laterally, 1–2xpd medially. Clypeus microreticulate, dull, very finely sparsely punctulate. Mentum very sparsely very finely punctulate, effacedly microreticulate, dull; postmentum finely densely micropunctulate, dull. Genae raised, shining, without posterior ridge.

Pronotum weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, except slightly produced in midline at large, slightly concave scintilla; punctures on disc much larger and deeper than those of frons, interstices shining, 1–2xpd, punctures larger and denser at anterior and posterior; PF1 and PF4 absent; PF2 shallow; PF3 moderately deep.

Elytra weakly arcuate laterally; summit of posterior declivity at about midlength; lateral explanate margins narrow; 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. 1xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect separately, rather widely rounded, in posterior aspect margins forming deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1.5/5/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques small, widest posteriorly, tapering to point anteriorly, straight, medial margins parallel, very weakly raised, located at sides of moderately deep median depression. Metaventrite with very short point on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 1.5x P2. Protibia very slightly arcuate, slightly widened in distal 1/2. Meso- and metatibia slender, straight. Abdominal apex very slightly asymmetrical; last tergite with small notch, slightly offset to left side.

Etymology. Named in reference to the very apparent stridulatory file on the head, and the corresponding large pronotal scintilla.

Distribution. Currently known only from the type locality ( Fig. 195 ).

Figures

FIGURE 27. Hydraena buscintilla, holotype, dorsal and lateral habitus, venter, and detail of scintilla and stridulatory file.

FIGURE 31. Hydraena mintrita, holotype, dorsal and lateral habitus, and venter.

FIGURE 195. Geographical distributions of Hydraena species in the Costiniceps Complex.