Hydraena decepta, 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 : 33-34

Hydraena decepta , new species

( Figs. 35 , 37, 444 )

Type Material. Holotype (male): Eastern Highlands Province: Okapa , gravel banks of deep fast river, 1524 m, 6° 32' S, 145° 37' E, 10 ii 1965, M. E. Bacchus (MEB 189a) ( NHM).

Differential Diagnosis. Recognized among members of the Manulea group by the combination of the large size (ca. 1.97 mm, others in group ca. 1.25–1.67 mm), the pronotal macula (others in group have a fascia or submacula), and the very narrow plaques (ratios ca. 4/1/8/5) ( Fig. 35 ). The male genitalia distinctively differ from that of other members of the Manulea group ( Fig. 37).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.97/0.81; head 0.30/0.41; pronotum 0.44/0.53, PA 0.44, PB 0.47; elytra 1.22/0.81. Dorsum of head dark brown; pronotum light brown around dark brown macula, ratios of color bands, as measured in midline, ca. 9/14/7; elytra brown; legs and maxillary palpi light brown, tip of palpus not 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 very sparsely very finely punctulate, shining; postmentum micropunctulate. Genae raised, shining, without posterior ridge. Pronotum subcordiform, median 1/2 of anterior margin emarginate; punctures on disc ca. 1xpd those of frons, interstices shining, 2–4xpd, punctures larger and denser at anterior and posterior; PF1 absent; PF2 shallow; PF3 deep; PF4 absent.

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. Intervals not raised, shining, on disc ca. 1–2xpd, 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. 4/1/8/5. P1 laminate; median carina sinuate in profile. P2 raised, l/w ca. 2/1, sides converging toward blunt apex. Plaques very narrow, parallel, located at sides of deep, median depression, each plaque posteriorly raised in point. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin very slightly greater than P2. All legs moderately long and very slender. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia moderately arcuate. Mesotibia very slightly arcuate. Metatibia straight. Abdominal apex symmetrical; last tergite (male) notched. Aedeagus as illustrated ( Fig. 37).

Etymology. Named in reference to similarities to other species in the group, found near Okapa.

Distribution. Currently known only from the type locality at Okapa, eastern Area 1, at an elevation of 1524 m ( Fig. 444 ).

Figures

FIGURE 35. Hydraena decepta, holotype, dorsal and lateral habitus, and venter.

FIGURES 443–446. Geographical distributions of Hydraena species.