Hydraena scintillarca, 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 : 29-30

Hydraena scintillarca , new species

Figs. 36 (habitus), 38 (aedeagus), 195 (map)

Type Material. Holotype (male): Peru : Cajamarca, Celendin area, 6° 52' S, 78° 8' W, 25 v – 11 vi 1936, F. Woytkowski. Deposited in the SEMC. Paratypes: Same data as holotype (2 SEMC).

Differential Diagnosis. Similar in dorsal habitus to H. scintillamima ( Figs. 35 , 36 ); differentiated therefrom by the more strongly arcuate sides of the pronotum, the wider elytra, especially in the posterior 1/3, and the truncate elytral apices. The elytral differences of the two species are even more apparent in females: in H. scintillarca the apices are strongly truncate, and when viewed posteriorly the elytra form a strong angle with one another; whereas in H. scintillamima females the elytral apices are weakly separately rounded, and when viewed posteriorly form a weak angle with one another. Additional differentiating characters include: the plaques are carinate in H. scintillarca , non-carinate in H. scintillamima ; the marginal setae of the last tergite of females are weakly hooked in H. scintillarca , and non-hooked in H. scintillamima . In both species the pronotum has a distinct scintilla. The aedeagi of the two species show a basic plan similarity, while distinctly differing in details ( Figs. 37, 38).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.73/0.74; head 0.26/0.42; pronotum 0.42/0.58, PA 0.44, PB 0.51; elytra 1.08/0.74. Dorsum brown to dark brown, head and disc of pronotum darkest; legs brown; maxillary palpi testaceous, tip not darker.

Frons punctures ca. 1–2xef, larger and denser near eyes than medially; interstices laterally microreticulate, dull, ca. 01xpd, medially shining, ca. 2–5xpd. Clypeus microreticulate laterally, very finely sparsely punctulate medially. Mentum microreticulate and very sparsely very finely punctulate, weakly shining; postmentum very finely densely micropunctulate, dull. Genae raised, shining, without posterior ridge.

Pronotum moderately arcuate laterally; anterior margin straight behind eyes, emarginate behind frons except slightly produced at distinct scintilla; punctures on disc much larger and deeper than those on frons, interstices weakly shining, 1–3xpd on disc, punctures larger and denser at anterior and posterior, sparser above and to sides of PF2; PF1 shallow; PF2 shallow; PF3 deep; PF4 shallow; PF3 and PF4 shallowly confluent.

Elytra weakly arcuate laterally; summit of posterior declivity slightly behind 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. 1–2xpd, as are interstices between punctures of a row, a few punctures subserial. Apices in dorsal aspect subtruncate, in posterior aspect margins forming rather strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/0.5/6/5. 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 very narrow, low subcarinate lines, straight slightly converging toward one another anteriorly, 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. 1.5x P2. Profemur (male) with small tubercle next to trochanter. Protibia slightly arcuate in distal 1/2, gradually and slightly increasing in width from base to subapically, medial margin with row of setae. Meso- and metatibia slender, straight. Male abdominal apex asymmetrical; last tergite with marginal notch, oblique and offset to left side. Female (microslide mount, n=1): last tergite broadly rounded, with rather deep apicomedian notch, ca. 14 thin, weakly hooked setae, apicomedian gap wide; gonocoxite not midlongitudinally divided, apical margin sharply rounded, low transverse ridge evident at border of microreticulation; spermatheca type C2.

Etymology. Named in reference to the arcuate sides of the pronotum, the arcuate elytral apices, when viewed in posterior aspect, and the distinct scintilla.

Distribution. Currently known only from the type locality ( Fig. 195 ).

Figures

FIGURE 35. Hydraena scintillamima, holotype, dorsal and lateral habitus, and venter.

FIGURE 36. Hydraena scintillarca, holotype, dorsal and lateral habitus, and venter.

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