Hydraena aquila, 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 : 75-76

Hydraena aquila , new species

( Figs. 123 , 125, 488 )

Type Material. Holotype (male): Madang Province: Simbai area , 1200 m, 5° 13.389' S, 144° 37.285' E, 10 iii 2007, Kinibel ( PNG 152) ( ZSM) . Paratypes: Same data as holotype (9 MCZ, NHM, NMW, PNG, ZSM) .

Differential Diagnosis. Similar in dorsal habitus to H. fascinata ; differentiated therefrom by the smaller size (ca. 1.56 vs. 1.76 mm), the less elongate elytra, the more coarsely punctate dorsum, and the more widely spaced plaques ( Figs. 122 , 123 . The male genitalia of the two species distinctively differ ( Figs. 124, 125).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.56/0.65; head 0.26/0.37; pronotum 0.36/0.46, PA 0.39, PB 0.37; elytra 0.95/0.65. Dorsum piceous, except anterior angles of pronotum dark brown; legs dark brown; maxillary palpi light brown, tip of palpus slightly darker.

Frons punctures ca. 1–2xef, slightly larger near eyes than medially; interstices shining, 1–5xpd. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Pronotum cordiform, median 2/3 of anterior margin emarginate; punctures on disc slightly smaller than those of frons, interstices shining, 2–6xpd, punctures much larger and denser at anterior and posterior; PF1 shallow; PF2 shallow; PF3 deep; PF4 shallow.

Elytra transversely convex, summit of posterior declivity slightly before midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, some 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. 3/3/9/3. P1 laminate; median carina sinuate in profile. P2 transversely roundly raised, l/w ca. 2/1, sides parallel for most of length. Plaques moderately wide posteriorly, weakly raised, medial margins parallel, located at sides of deep, median depression, each plaque tapering markedly from posterior to anterior. Metaventrite with very low, indistinct midlongitudinal ridge. AIS width at straight posterior margin slightly greater than P2. All legs moderately long and slender. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia straight, lateral margin weakly arcuate, medial margin straight except indented subapically where located ca. two short spines. Mesotibia straight or extremely weakly arcuate. Metatibia arcuate, distal 1/2 of medial margin with sparse, long, hair-like setae. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 125).

Etymology. The aedeagus recalls a screaming eagle.

Distribution. Currently known only from the type locality, the Simbai area, in north central Area 1 near the border with Area 2; elevation 1200 m ( Fig. 488 ).

Figures

FIGURE 122. Hydraena fascinata, holotype, dorsal and lateral habitus, and venter.

FIGURE 123. Hydraena aquila, holotype, dorsal and lateral habitus, and venter.

FIGURES 487–490. Geographical distributions of Hydraena species.