Hydraena mianminica, 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 : 35

Hydraena mianminica , new species

( Figs. 39 , 41, 447 )

Type Material. Holotype (male): Sandaun Province: May River , ex river side pool, 970 m, 4° 49.779' S, 141° 38.174' E, 19 x 2003, K. Sagata (WB 41) ( ZSM) . Paratypes (16): Sandaun Province: Same data as holotype (8 MCZ, NHM, NMW, PNG, ZSM) ; Mianmin, pool, 990 m, 4° 54.57' S, 141° 35.49' E, 23 x 2008, S. Ibalim ( PNG 193) (3 ZSM) ; Mianmin, river, 700 m, 4° 52.858' S, 141° 31.706' E, 21 x 2008, S. Ibalim ( PNG 197) (5 ZSM) .

Differential Diagnosis. Among members of the Manulea group, similar in body shape to H. thumbelina ( Figs. 27 , 39 ); differing therefrom by the larger size (ca. 1.67 vs. 1.40 mm), the straight anterior margin of the pronotum, the subserial to random discal elytral punctures, and the differently shaped metaventral plaques. The male genitalia of the two species distinctively differ ( Figs. 29 , 41).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.64; head 0.26/0.36; pronotum 0.39/0.47, PA 0.39, PB 0.37; elytra 0.98/0.64. Dorsum of head piceous; pronotum light brown to testaceous in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 6/16/4, posterior color band very faint; elytra dark brown; legs and maxillary palpi brown, tip of palpus slightly darker.

Frons punctures ca. 1xef, 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, anterior margin straight; punctures on disc ca. 1xpd those of frons, interstices shining, 1–5xpd, punctures slightly larger and denser at anterior and posterior; PF1 absent; PF2 very shallow, obsolete; PF3 deep; PF4 very shallow.

Elytra with summit of posterior declivity at or very near midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming gradually smaller toward posterior; many punctures subserial or random. Intervals not raised, shining, on disc ca. 1–3xpd, 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. 3/2/8/3. P1 laminate; median carina sinuate in profile. P2 raised, l/w ca. 2/1, sides converging toward blunt apex. Plaques moderately wide, parallel, weakly raised, located at sides of deep, median depression, each plaque tapering from posterior to anterior. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin ca. 1.7x P2. All legs moderately long and slender. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia slightly arcuate, distal 1/3 widened on anteromedial margin and apically with cluster of very short spines. Meso- and metatibia straight. Abdominal apex symmetrical; last tergite (male) notched. Aedeagus as illustrated ( Fig. 41).

Etymology. Named in reference to the geographical distribution.

Distribution. Currently known only from a few localities at or near Mianmin. The elevation range, 700–990 m, places these records in the western part of Area 2, but very near higher elevations that would be considered Area 1 sites ( Fig. 447 ).

Figures

FIGURE 27. Hydraena thumbelina, holotype, dorsal and lateral habitus, and venter.

FIGURE 39. Hydraena mianminica, holotype, dorsal and lateral habitus, and venter.

FIGURES 447–450. Geographical distributions of Hydraena species.

FIGURES 28–29. Aedeagi of holotypes. 28. H. sepikramuensis. 29. H. thumbelina.