Hydraena boliviana, 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 : 15

Hydraena boliviana , new species

Figs. 4 (habitus), 13 (aedeagus), 154 (spermatheca), 193 (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° 44' S, 66° 40' W, 14 ix 1987, W. E. Steiner. Deposited in the USNM. Paratypes: Same data as holotype (3 USNM).

Differential Diagnosis. Similar in dorsal habitus to H. paeminosa ( Figs. 3 , 4 ); differing therefrom by the pronotal shape, which is narrower anteriorly (PA/PB ca. 40/47 vs. 43/45), and the slightly shorter and wider elytra. Reliable determinations will also include examination of the male genitalia ( Figs. 9, 13).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.71/0.72; head 0.26/0.37; pronotum 0.40/0.49, PA 0.40, PB 0.47; elytra 1.05/0.72. Dorsum of head with frons dark brown to piceous, clypeus dark brown; pronotum dark brown, slightly lighter near anterior margin; elytra and legs dark brown; palpi testaceous, tip not darker.

Dorsum of head microreticulate, dull. Frons punctures ca. 1.5xef laterally, much smaller medially, interstices laterally ca. 1xpd to narrow walls. Clypeus punctures obsolete. Mentum microreticulate, sparsely finely punctulate, dull; postmentum microreticulate and densely punctulate, dull. Genae posteriorly raised in low ridge, except midline lacking ridge.

Pronotum and elytra coarsely densely punctate, subscabrous, interstices microreticulate, more markely on pronotum than elytra. Pronotum with median 1/3 of anterior margin emarginate, and with very narrow, nearly imperceptible hyaline border in midline; scintilla absent; PF1 and PF2 absent; PF3 and PF4 deep, confluent, separated from lateral margin by low irregular ridge. Elytra quite convex at summit of posterior declivity, at about midlength; lateral explanate margins narrow; punctures random in basal 1/2, becoming serial over posterior declivity, then random near apices. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming moderately deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. x/1.5/8/4. P1 slightly wider than laminate; median carina sinuate in profile. P2 narrow, tapering to sharp point, tip contiguous with low median carina of metaventrite. Plaques moderately wide, parallel, weakly raised, located at sides of moderately deep median depression. Metaventrite with median carina in anterior 2/3, extended from anterior margin to middle of median depression, also with short point on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. equal plaque separation. Protibia slightly arcuate, very slightly widened in distal 1/2. Meso- and metatibia very slightly arcuate, slender, mesotibia flat on inner margin in distal 1/2. Male abdominal apex symmetrical; last tergite without apicomedian notch. Female abdominal apex: last tergite broadly rounded, without apicomedian notch, ca. 38 (n=1) slightly hooked, sharply pointed, long, slender, rather closely spaced setae that are not in a single row; gonocoxite divided by weakly sclerotized midlongitudinal area, apical margin transverse, basal area lacking transverse ridge.

Etymology. Named in reference to the geographical distribution.

Distribution. Currently known only from the type locality ( Fig. 193 ).

Figures

FIGURE 3. Hydraena paeminosa, holotype, dorsal and lateral habitus, and venter.

FIGURE 4. Hydraena boliviana, holotype, dorsal and lateral habitus, and venter.

FIGURES 193 – 194. 193. Geographical distributions of species in the Paeminosa Group. 194. Geographical distributions of species in the Curvosa and Multispina Groups.