Hydraena altiphila, 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 : 60

Hydraena altiphila , new species

Figs. 123 (habitus), 125 (aedeagus), 163 (female abd.), 198 (map)

Type Material. Holotype (male): Venezuela : Merida; Rio Milla at Merida Zoo, margin and wet rock, elev. 1750– 1850 m, 8° 38' N, 71° 9' W, 14 i 2006, Short, Torres (AS-06-026). Deposited in the MIZA. Paratypes (21): Venezuela : Merida, Merida, Monte Zerpa area, tributary of Rio Albarregas, stream margins and pools, elev. 2037 m, 8° 38.006' N, 71° 9.762' W, 20 vii 2009, Short, Gustafson, Garcia, Camacho, Inciarte (VZ09-0720-01A) (21 SEMC).

Differential Diagnosis. A moderately broad species with a pronotal fascia bordered in front and behind by brown color. The plaques are narrow and, in males, raised slightly posteriorly. Similar in habitus to H. spatula ( Figs. 122–123 ); differentiated therefrom by the smaller size (ca. 1.69 vs. 1.85 mm), the broader form, the wider P2 and shorter plaques (plaque ratios ca. 2.5/1/6/4 vs. 2/1.5/9/4), and differences in the male legs. The aedeagi of the two species differ markedly, but show a general plan similarity, and stand apart from other species by the very large, spatula-like distal lobe ( Figs. 124–125).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.69/0.69; head 0.27/0.40; pronotum 0.39/0.57, PA 0.45, PB 0.50; elytra 1.04/0.69. Dorsum of head piceous; pronotum brown in front of and behind dark brown to piceous fascia, ratios of color bands, as measured in midline, ca. 7/15/5; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker. Body form broad.

Frons punctures ca. 1–2xef, larger and denser near eyes than medially; interstices microreticulate and dull laterally, shining medially, 0.5–1xpd laterally, 2–4xpd medially. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge.

Pronotum arcuate laterally; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; punctures on disc much larger and deeper than those on frons, interstices shining, 1–3xpd medially, punctures larger and denser at anterior, posterior and laterally; PF1 absent; PF2 oval, shallow; PF3 deep; PF4 very shallow.

Elytra weakly arcuate laterally; summit of posterior declivity slightly before midlength; lateral explanate margins wide; on basal 1/3 punctures slightly smaller than largest pronotal punctures, punctures becoming finer 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 rounded, in posterior aspect margins forming very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2.5/1/6/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, slightly arcuate, slightly converging toward one another anteriorly, weakly raised posteriorly, located at sides of 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. 2x P2. Protibia slightly arcuate, medial margin with row of rather long setae in ca. middle 1/3. Meso- and metatibia slender, straight. Male abdominal apex very slightly asymmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1) ( Fig. 163 ): last tergite broadly rounded, with shallow, moderately broad apicomedian notch, ca. 22 very weakly hooked setae, apicomedian gap wide; gonocoxite not midlongitudinally divided, apical margin sharply rounded, low transverse ridge evident at border of microreticulation; spermatheca type C1, accessory gland cup large.

Etymology. Named in reference to the high altitude of the collecting localities.

Distribution. Currently known from two narrowly separated localities in northwestern Venezuela ( Fig. 198).

Notes. This species has been collected at a higher altitude than any other Hydraena in Venezuela (2037 m) ; only Ecuador and Peru have higher Hydraena localities.

Figures

FIGURE 122. Hydraena spatula, holotype, dorsal and lateral habitus, and venter.

FIGURE 123. Hydraena altiphila, holotype, dorsal and lateral habitus, and venter.

FIGURES 163 – 166. Female tergite X and gonocoxite of Hydraena species.