Hydraena pectenata, Perkins, 2011

Perkins, Philip D., 2011, New species (130) of the hyperdiverse aquatic beetle genus Hydraena Kugelann from Papua New Guinea, and a preliminary analysis of areas of endemism (Coleoptera: Hydraenidae) 2944, Zootaxa 2944 (1), pp. 1-417 : 122-123

Hydraena pectenata , new species

( Figs. 223 , 225, 413 , 536 )

Type Material. Holotype (male): Madang Province: Finisterre Mts., Naho River Valley, Damanti , ex small pool, probably permanent, in clay in dense shade, 1067 m, 5° 55' S, 145° 58' E, 8 x 1964, M. E. Bacchus (MEB 39) ( NHM) . Paratypes: Same data as holotype (213 NHM) .

Differential Diagnosis. Similar in dorsal habitus and plaque ratios to H. ulna ( Figs. 222 , 223 ); differing therefrom in slightly smaller size (ca. 1.46 vs. 1. 57 mm), more densely punctate pronotum (discal interstices ca. 1–2 vs. 2–4 xpd). The male genitalia of the two species also show a relationship, while differing distinctively in several details ( Figs. 224, 225).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.46/0.65; head 0.20/0.34; pronotum 0.40/0.50, PA 0.38, PB 0.46; elytra 0.87/0.65. Dorsum of head dark brown to piceous; pronotum dark brown in front of and behind piceous, very diffusely margined, fascia, ratios of color bands, as measured in midline, ca. 7/15/5; elytra dark brown; legs brown; maxillary palpi testaceous, tip not darker. Dorsum moderately shining.

Frons punctures ca. 1xef near eyes, smaller and sparser medially; interstices 1–4xpd, microreticulate and dull laterally, smooth and shining medially. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate and shining medially. Mentum effacedly microreticulate, very sparsely very finely punctulate, weakly shining. Postmentum microreticulate in shallow median depression, otherwise finely sparsely punctate. Genae very slightly raised, shining, with shallow, obsolete median impression, without posterior ridge. Pronotum transverse, anterior margin straight, sides straight or very slightly arcuate between anterior angle and widest part, arcuate at middle, sinuate between widest part and posterior angle; punctures on disc ca. 2–3xpd largest frons punctures, interstices shining, ca. 1–2xpd, punctures anteriorly and posteriorly ca. 2xpd those on disc; PF1, PF2 and PF4 very shallow; PF3 moderately deep, wide.

Elytra widest at about midlength; summit of posterior declivity at or very near midlength; lateral explanate margins moderately wide; on basal 1/3 punctures slightly smaller than largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/2/8/3. P1 laminate; median carina sinuate in profile, slightly raised behind coxae. P2 length/width ca. 5/3, sides very slightly diverging toward blunt, slightly raised apex. Plaques flat or slightly rounded, at sloping sides of median depression, anteriorly tapering and convergent, narrowly separated at anterior extreme. Metaventrite flat between mesocoxae. AIS width at straight posterior margin ca. 1.5x P2. All legs of moderate length. Profemur (male) with small tubercle on ventral margin near trochanter; protibia straight, medial margin slightly widened in distal 1/2. Meso- and metatibia straight, slender. Abdominal apex very slightly asymmetrical; last tergite (male) with very small apicomedian notch. Aedeagus as illustrated ( Fig. 225). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 413 ).

Etymology. "Comb-like qualities"; named in reference to the rows of spines on the meso- and metatibiae of males, the slender processes of the aedeagus, and the dentate tenth tergum of females.

Distribution. Currently known only from the type locality, Damanti, in the Finisterre Mts. (Area 5), at the bor- der with Area 3; elevation 1067 m ( Fig. 536 ).

Figures

FIGURE 222. Hydraena ulna, holotype, dorsal and lateral habitus, and venter.

FIGURE 223. Hydraena pectenata, holotype, dorsal and lateral habitus, and venter.

FIGURES 412–415. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 535–538. Geographical distributions of Hydraena species.