Hydraena intensa, 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 : 33

Hydraena intensa , new species

( Figs. 34 , 36, 449 )

Type Material. Holotype (male): Morobe Province: Lae–Bulolo road, ex stones and gravel bank of large river, 6° 52' S, 146° 37' E, 28 xii 1964, M. E. Bacchus (MEB 124) ( NHM).

Differential Diagnosis. Among members of the Manulea group, somewhat similar in body shape to H. mianminica ( Figs. 34 , 39 ); differing therefrom by the smaller size (ca. 1.44 vs. 1.67 mm), the darker dorsal coloration, and the larger and differently shaped metaventral plaques (ratios ca. 3/3/10/2 vs. 3/2/8/3). The male genitalia of the two species distinctively differ ( Figs. 36, 41). In addition, in males of H. intensa the metatibiae have a brush of setae on the medial margin.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.44/0.57; head 0.23/0.34; pronotum 0.35/0.42, PA 0.36, PB 0.35; elytra 0.86/0.57. Dorsum of head piceous; pronotum dark brown in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 4/17/3; elytra dark brown; legs dark brown; maxillary palpi brown, tip of palpus not darker.

Frons punctures ca. 1xef, slightly larger near eyes than medially; interstices shining, 2–4xpd, anterolateral angles microreticulate. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Pronotum subcordiform, median 1/2 of anterior margin emarginate; punctures on disc slightly larger and deeper than those of frons, interstices shining, 1–4xpd, punctures slightly larger and denser at anterior and posterior; PF1 absent; PF2 very shallow, obsolete; PF3 deep; PF4 absent.

Elytra with summit of posterior declivity at or very near midlength; lateral explanate margins rather wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–3xpd, as are interstices between punctures of a row, a few punctures subserial. 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. 3/3/10/2. P1 laminate; median carina sinuate in profile. P2 raised, l/w as ca. 5/3, sides converging toward blunt apex. Plaques very large, converging very slightly anteriorly, roundly raised, separated by median depression, each plaque tapering slightly from posterior to anterior. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin very slightly wider than P2. All legs moderately long and slender. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia slightly arcuate, gradually increasing in width from base to apex, medial margin apically with cluster of very short spines. Mesotibia slightly arcuate. Metatibia straight, gradually increasing in width from base to apex, distal 1/3 of medial margin with long hair-like setae. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 36).

Etymology. "Stretched tight"; named in reference to the elongate body form, elongate and slender legs, and to the "stretched" process of the aedeagus.

Distribution. Currently known only from the type locality at the far eastern limit of Area 3; elevation 900– 1100 m ( Fig. 449 ).

Figures

FIGURE 34. Hydraena intensa, 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.