Hydraena amazonica, 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 : 27-28

Hydraena amazonica , new species

Figs. 32 (habitus), 34 (aedeagus), 175 (spermatheca), 195 (map)

Type Material. Holotype (male): Peru : Loreto, Iquitos, ex. flight intercept trap, elev. 90 m, 3° 45' S, 73° 15' W, 7 v 1992, J. Danoff-Berg. Deposited in the SEMC. Paratype: Same data as holotype (1 SEMC).

Differential Diagnosis. A dull, mostly microreticulate species with fine but rather dense punctation, and lacking a distinct pronotal macula or fascia. The pronotum has a large, concave scintilla in males (much smaller in females) and the elytral punctation on the basal 1/3 is mostly random. Somewhat similar in dorsal habitus to H. cherylbarrae ( Figs. 24 , 32 ); differentiated therefrom by the finer punctation and more evident microreticulation, the random punctures on the base of the elytra, the longer elytra, and in having the metaventral plaques about as wide as P2. The aedeagi of the two species show some similarity in basic plan, but markedly differ in many details ( Figs. 26, 34).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.39/0.54; head 0.22/0.35; pronotum 0.36/0.47, PA 0.37, PB 0.43; elytra 0.88/0.54. Dorsum of head with frons dark brown to piceous, clypeus brown; pronotum light brown to brown, without distinct macula; elytra brown; legs brown; maxillary palpi testaceous, tip not darker.

Frons microreticulate, dull, punctures ca. 0.5–1xef, slightly larger and denser near eyes than medially; interstices laterally ca. 0.5–1xpd, medially ca. 1–4xpd. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum microreticulate and very sparsely very finely punctulate, dull; postmentum very finely densely micropunctulate and dull in median concavity, surrounding areas smooth, shining. Genae raised, shining, without posterior ridge.

Pronotum weakly arcuate laterally; anterior margin straight behind eyes, emarginate behind frons except slightly produced at distinct, large, concave scintilla; punctures on disc ca. 1xpd of largest punctures on frons, interstices microreticulate, dull, 1–3xpd on disc, punctures slightly denser at anterior and posterior; PF1 absent; PF2 large but very shallow; PF3 moderately deep; PF4 very shallow; PF3 and PF4 shallowly confluent.

Elytra weakly arcuate laterally; summit of posterior declivity at about midlength; lateral explanate margins narrow; most elytral punctures subserial or random on basal 1/3, some becoming serial over posterior declivity; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming slightly smaller and more widely spaced toward posterior. Intervals not raised, effacedly microreticulate, weakly shining, on basal 1/3 ca. 1–2xpd, as are interstices between punctures. Apices in dorsal aspect separately rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1.5/1.5/5/4. P1 laminate; median carina sinuate in profile. P2 narrow, l/w ca. 3/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques moderately wide posteriorly, tapering anteriorly, straight, converging toward one another anteriorly, weakly raised, located at sides of 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. 3x P2. Protibia very slightly arcuate, medial margin distinctively produced and bearing short setae at ca. distal 3/4. Mesotibia slender, straight. Metatibia slender, very slightly sinuate, in ventral aspect. Male abdominal apex asymmetrical; last tergite obliquely oriented, without apicomedian notch. Female (microslide mount, n=1): last tergite sharply rounded, with apicomedian thin slit, ca. 26 long, narrow, hooked setae, apicomedian gap very small; gonocoxite not midlongitudinally divided, apical margin broadly rounded, no transverse ridge evident at border of microreticulation; spermatheca type C2.

Etymology. Named in reference to the geographical distribution.

Distribution. Currently known only from the type locality ( 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.