Hydraena saluta, 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 : 87-88

Hydraena saluta , new species

( Figs. 147 , 149 , 337–339 , 495 )

Type Material. Holotype (male): Madang Province: Finisterre Mts., Naho River Valley, Damanti , ex gravel banks of very fast-running clear stream, 914 m, 5° 55' S, 145° 58' E, 11 x 1964, M. E. Bacchus (MEB 47) ( NHM) . Paratypes (18): Madang Province: Adelbert Mts. , Sewan, 350 m, 4° 41.011' S, 145° 26.912' E, 3 v 2006, Balke & Manaono ( PNG 50) (2 ZSM) ; Finisterre Mts. , Naho River Valley, Damanti, ex gravel banks of very fast-running clear stream, 914 m, 5° 55' S, 145° 58' E, 11 x 1964, M. E. Bacchus (MEB 47) (9 NHM) ; Keki–Sewan , Adelbert Mts., 300 m, 4° 40.558' S, 145° 27.187' E, 30 xi 2006, Binatang Boys ( PNG 121) (3 ZSM) ; Sepik Ramu Basin , Kojé Creek, unshaded creek, small to medium cobbles, gravel and fine sand (the latter in areas of slack water), filamentous algae on stony substrates, small accumulations of leaf litter, 160 m, 5° 33' S, 145° 23' E, 1 vii–30 viii 1988, D. Dudgeon (1 NMW) ; Morobe Province: Kassam Pass , Yung Creek, [GE est.] 1300–1500 m, 6° 12' S, 146° 0' E, 14 vi 1979, W. G. Ullrich (1 MHNG) ; Western Highlands Province: Jimi Valley , Sendiap Station, 500– 600 m, 5° 20.728' S, 144° 27.401' E, 5 iii 2007, Kinibel ( PNG 146) (2 ZSM) .

Differential Diagnosis. Differentiated from other members of the Spinobesa group by the very sparsely punctate pronotum that has moderately large impunctate areas anterior and lateral to each foveae PF2, the comparatively large metaventral plaques, and the very small body size (ca. 1.23 mm) ( Fig. 147 ). The aedeagus distinctively differs, most notably in the shapes of the parameres, from that of other members of the group ( Fig. 149 ). The very complicated chaetotaxy of the protibia is illustrated with SEMs ( Figs. 337–339 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.23/0.56; head 0.18/0.33; pronotum 0.29/0.44, PA 0.36, PB 0.37; elytra 0.79/0.56. Dorsum dark brown to piceous; legs brown; maxillary palpi light brown to testaceous, tip not darker.

Frons punctures ca. 1–2xef, larger and denser near eyes than medially; interstices effacedly microreticulate, weakly shining, 1–3xpd. Clypeus microreticulate laterally, finely, sparsely punctate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Pronotum transverse (PL/PW ca. 0.66), ca. median 3/5 of anterior margin very slightly arcuate to posterior; punctures on center of disc ca. 2–3xpd frons punctures, interstices on disc shining, 1–3xpd, punctures slightly larger and denser at anterior and posterior; moderately large impunctate area anterior to and lateral to each PF2; sculpture laterally densely punctate, subrugulose in PF4; PF1 very shallow, obsolete; PF2 moderately deep; PF3 deep; PF4 shallow.

Elytra with summit of posterior declivity slightly anterior to midlength; lateral explanate margins narrow; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, weakly shining, on disc ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/3/1.5. P1 laminate; median carina sinuate in profile. P2 raised slightly at tip, l/w ca. 5/3, sides parallel, apex blunt. Plaques narrow, parallel, weakly raised except minutely carinate basally, at sides of median depression that continues shallowly to tip of P2. AIS width at straight posterior margin almost 2xP2. All legs rather short, femora moderately robust. Profemur (male) without tubercle next to trochanter; protibia very slightly arcuate, widest slightly past midlength, lateral margin arcuate and bearing short stout spines in widest part. Mesotibia straight, lateral margin slightly arcuate and bearing prominent, nearly contiguous row of short stout spines. Metatibia straight, gradually increasing in width from base to apex, medial margin with few moderately long setae in distal 1/3. Abdominal apex symmetrical; last tergite (male) notched. Aedeagus as illustrated ( Fig. 149 ).

Etymology. "Greet, salute"; named in reference to the prominent right paramere which extends beyond the aedeagal apex.

Distribution. Having a broad elevation range of 160–1500 m, but with only one locality above 914 m; currently known from Areas 1–3, and 5, basically in and on each side of the eastern part of Area 3 ( Fig. 495 ).

Figures

FIGURE 147. Hydraena saluta, holotype, dorsal and lateral habitus, and venter.

FIGURES 148–149. Aedeagi of holotypes. 148. H. owenobesa. 149. H. saluta.

FIGURES 334–339. Scanning electron micrographs of H. spinobesa (334–336) and H. saluta (337–339).

FIGURES 495–498. Geographical distributions of Hydraena species.