Hydraena beniensis, 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 : 43

Hydraena beniensis , new species

Figs. 75 (habitus), 79 (aedeagus), 199 (map)

Type Material. Holotype (male): Bolivia: Beni, 40 km E. San Borja, Estacion Biologica Beni, Palm Camp at Rio Curiraba, ex. small pool on sand bar, edge of sunlit river, 14 ix 1987, W. E. Steiner. Deposited in the USNM. Paratypes: Same data as holotype (5 USNM).

Differential Diagnosis. A small species (ca. 1.25 mm) with a distinctive pronotal fascia. The dorsal punctures are relatively small, but not widely separated, interstices ca. 1xpd on both the pronotal disc and the basal 1/3 of the elytra. Similar in size and dorsal habitus to H. delvasi ( Figs. 75 , 96 ); differing therefrom by the smaller pronotal fascia, the shining (non-microreticulate) disc of the frons, and the more elongate elytra; the aedeagi of the two species differ markedly ( Figs. 79, 99 ). The aedeagus of H. beniensis is more similar to that of H. trinidensis Perkins ( Fig. 73), but that species is larger (ca. 1.34 vs. 1.25 mm). Reliable determinations will require dissection of the male genitalia.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.25/0.51; head 0.18/0.32; pronotum 0.31/0.41, PA 0.35, PB 0.38; elytra 0.76/0.51. Dorsum of head piceous; pronotum testaceous in front of and behind piceous fascia, laterally fascia becoming smaller and brown, ratios of color bands, as measured in midline, ca. 5/11/5; elytra brown; legs testaceous; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1xef, slightly larger and denser near eyes than medially; interstices laterally effacedly microreticulate, weakly shining, ca. 0.5–1xpd, medially shining, ca. 1–2xpd. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum moderately sparsely moderately finely punctulate, shining; postmentum anteriorly shining, sparsely punctulate, posteriorly very finely densely micropunctulate, dull. Genae raised, shining, without posterior ridge.

Pronotum weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent or obsolete; punctures on disc ca. 1xpd those on frons, interstices shining, 1–4xpd on disc, punctures slightly larger and denser at anterior and posterior; PF1, PF2, and PF4 absent; PF3 moderately deep.

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. 1–2xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect conjointly, rather sharply rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1.5/5/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides parallel or nearly so, apex blunt, raised slightly above mesoventral intercoxal process. Plaques moderately narrow, straight, very slightly converging toward one another anteriorly, weakly transversely rounded, located at sides of moderately deep 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 weakly arcuate in proximal 1/2, medial margin slightly widened in distal 1/2. Meso- and metatibia slender, straight. Abdominal apex symmetrical; last tergite with deep apicomedian notch. Females not yet known.

Etymology. Named in reference to the type locality.

Distribution. Currently known only from the type locality ( Fig. 199).

Figures

FIGURE 75. Hydraena beniensis, holotype, dorsal and lateral habitus, and venter.

FIGURE 96. Hydraena delvasi, holotype, dorsal and lateral habitus, and venter.

FIGURES 99 – 101. Aedeagi of holotypes, and aedeagus of H. delvasi non-type from Venezuela.