Hydraena cherylbarrae, 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 : 24-25

Hydraena cherylbarrae , new species

Figs. 24 (habitus), 26 (aedeagus), 195 (map)

Type Material. Holotype (male): Venezuela : Territorio Federal Amazonas, Puerto Ayacucho (40 km S.), El Tobogan , Cano Coromoto, berlesed damp leaves, ditch edge, 24 i 1989, P. J. Spangler, R. Faitoute, C. B. Barr. Deposited in the MIZA. Paratypes (3): Venezuela : Territorio Federal Amazonas, same data as holotype (2 USNM); Puerto Ayacucho (39 km S.), Samariapo road, brook, colln. #4, 15 xi 1987, P. J. Spangler & R. A. Faitoute (1 USNM)

Differential Diagnosis. A medium sized species with a piceous pronotal macula surrounded by dark brown, and having a distinct scintilla. The dorsal punctation is moderately coarse, and rather dense; the interstices between the elytral punctures are small, only 0.5–1xpd. Somewhat similar in size and dorsal habitus to H. amazonica ( Figs. 24 , 32 ); differing therefrom in having coarser dorsal punctation, less evident microreticulation, wider elytra, and metaventral plaques that are only about half as wide as P2. The aedeagi of these two species differ markedly ( Figs. 26, 34). The aedeagus of H. cherylbarrae indicates a relationship with H. costiniceps Perkins 1980 ( Fig. 25); a species that is larger (ca. 1.60 vs. 1.30) and has a slightly differently shaped pronotum. Reliable determinations will include examination of the male genitalia.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.30/0.56; head 0.24/0.33; pronotum 0.33/0.44, PA 0.36, PB 0.40; elytra 0.80/0.56. Dorsum of head piceous; pronotum brown to dark brown around subrectangular piceous macula, ratios of color bands, as measured in midline, ca. 6/12/5; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 2xef, very slightly larger and denser near eyes than medially; interstices laterally microreticulate, dull, ca. 0.5–1xpd, medially shining, ca. 0.5–2xpd. Clypeus microreticulate, dull, very finely sparsely punctulate medially. Mentum effacedly microreticulate, very sparsely very finely punctulate, dull; postmentum very 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 at distinct scintilla; punctures on disc larger and deeper than those on frons, interstices shining, 1–3xpd on disc, punctures larger and denser at anterior and posterior; PF1 very shallow; PF2 shallow; PF3 very deep; PF4 shallow; PF3 and PF4 shallowly confluent.

Elytra weakly arcuate laterally; summit of posterior declivity at about midlength; lateral explanate margins moderately wide; 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. 0.5–1xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect subtruncate rounded, in posterior aspect margins forming rather deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/6/4. P1 laminate; median carina sinuate in profile. P2 l/ w ca. 2/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight, 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 very slightly arcuate, if at all. Meso- and metatibia slender, straight. Abdominal apex slightly asymmetrical; last tergite with notch offset to left side.

Etymology. Named in honor of the collector, Cheryl Barr.

Distribution. Currently known only from the type locality and a nearby site ( Fig. 195 ).

Figures

FIGURE 24. Hydraena cherylbarrae, holotype, dorsal and lateral habitus, and venter.

FIGURE 32. Hydraena amazonica, holotype, dorsal and lateral habitus, and venter.

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