Hydraena fasciopaca, 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 : 100-101

Hydraena fasciopaca , new species

( Figs. 174 , 176, 510 )

Type Material. Holotype (male): Madang Province: Keki , Adelbert Mts., 400 m, 4° 43.058' S, 145° 24.437' E, 29 xi 2006, Binatang Boys ( PNG 119) ( ZSM) . Paratypes (14): Madang Province: Same data as holotype (8 MCZ, NHM, NMW, PNG, ZSM); Keki– Sewan , Adelbert Mts., 300 m, 4° 40.558' S, 145° 27.187' E, 30 xi 2006, Binatang Boys ( PNG 121) (6 MCZ, NHM, NMW, PNG, ZSM) .

Differential Diagnosis. Readily differentiated from other members of the Cristatigena group by the combination of small size (ca. 1.39 mm) and the color, having a dark brown pronotal fascia that is bordered anteriorly and posteriorly by testaceous ( Fig. 174 ); also differing from the other members of the species group by the short, oval elytra and the non-sexually dimorphic hind legs. The aedeagus has some superficial similarity to that of H. cristatigena ( Figs. 160 , 176).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.39/0.73; head 0.21/0.39; pronotum 0.35/0.50, PA 0.43, PB 0.40; elytra 0.43/0.40. Head dark brown to piceous; pronotum with large fascia, dark brown on disc, light brown laterally, testaceous transverse borders anterior and posterior to fascia; elytra brown, except explanate margin light brown or testaceous; legs light brown; palpi light brown, except distal 1/2 of last palpomere slightly darker.

Dorsum of head and pronotum densely punctulate, dull; pronotal disc subrugulose; punctures of frons disc and pronotal disc ca. 1xef, interstices narrow walls to ca. 1xpd; punctures of clypeus obsolete. Labrum apicomedially excised, lobes rounded, free margins weakly upturned. Mentum sparsely punctate, shining; postmentum anterior 1/ 2 with punctation similar to mentum, posterior 1/2 densely micropunctulate. Genae raised, posterior ridge strong. Pronotum with anterior margin weakly emarginate over middle 1/2, emargination with very narrow hyaline border; pronotal foveae on disc moderately deep, PF2's shallowly confluent with one another in middle; PF3 and PF4 much deeper than PF1 and PF2.

Elytra quite oval, dull, punctures ca. 1xpd of largest pronotal punctures, each with minute seta and three granules, one at anterior margin and one on each side. Intervals not raised, width ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins not forming angle with one another. Explanate margin wide, wider than widest part of metatibia.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/1/4/5. P1 laminate; median carina sinuate in profile. P2 moderately narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques very narrow, weakly raised, located at lateral margins of median depression. Metaventrite tumid lateral to plaques. No midlongitudinal carina between mesoventral intercoxal process and plaques. Hydrofuge pubescence dense. AIS flat, width at straight posterior margin ca. 1.5x P2. Protibia (male) widened, medial surface very flat; mesotibia simple; metatibia slender, gradually widening from base to apex, straight or nearly imperceptibly arcuate. Abdominal apex symmetrical.

Aedeagus ( Fig. 176) main piece with large distal lobe, in ventral aspect lobe apically sharply rounded, medial margin broadly rounded; left paramere moderately sized, constricted at midlength, not bilobed, setae in two clusters; right paramere markedly constricted before midlength, apical part somewhat spearhead shaped; distal piece, in right lateral view, with characteristic shape.

Etymology. Named in reference to the pronotal fascia and dull dorsum.

Distribution. Currently known only from two very narrowly separated localities in the Adelbert Mts., in northwestern Area 5; elevations 300 m and 400 m ( Fig. 510 ).

Figures

FIGURE 174. Hydraena fasciopaca, holotype, dorsal and lateral habitus, and venter.

FIGURES 507–510. Geographical distributions of Hydraena species.

FIGURES 160–161. Aedeagi. 160. H. cristatigena, non-type specimen from E. Highlands, Wanatabe Valley, nr. Okapa. 161. H. variopaca, holotype.