Hydraena marawaka, 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 : 47

Hydraena marawaka , new species

( Figs. 62 , 64, 450 )

Type Material. Holotype (male): Gulf Province: Marawaka , Mala, 1400 m, 7° 5.664' S, 145° 44.467' E, 11 xi 2006, Balke & Kinibel ( PNG 90) ( ZSM) . Paratype: same data as holotype (1 male, ZSM) .

Differential Diagnosis. Similar in dorsal habitus to H. cheesmanae ; differing therefrom in larger size (ca. 1.56 vs. 1.37), and metaventral plaque shape, which are more widely separated and have raised lateral margins ( Figs. 59 , 62 ). The male metatibiae differ very slightly in shape in the two species, but H. marawaka has longer setae on the brush. The male genitalia of the two species also suggest a relationship, but differ distinctively in many details ( Figs. 61 , 64).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.56/0.64; head 0.23/0.36; pronotum 0.39/0.45, PA 0.39, PB 0.39; elytra 0.92/0.64. Dorsum of head piceous; pronotum testaceous in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 7/14/5; elytra dark brown; legs light brown; maxillary palpi testaceous, tip slightly darker.

Frons punctures ca. 1–2xef, 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 effacedly micropunctulate. Genae raised, shining, without posterior ridge. Pronotum cordiform, median 2/ 3 of anterior margin emarginate; punctures on disc ca. 1xpd 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 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. 1–3xpd, 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. 3/3/8/4. P1 laminate; median carina sinuate in profile. P2 raised, l/w ca. 2/1, sides slightly converging toward blunt apex. Plaques large, converging slightly anteriorly, transversely raised, more so laterally than medially, located at sides of deep median depression, each plaque tapering slightly from posterior to anterior. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin ca. 1.7x P2. All legs long and slender. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia straight, widest subapically, cluster of small spines on anteromedial margin at this point, moderately long spine on medial surface at ca. distal 1/3. Mesotibia straight. Metatibia straight, medial margin in distal 1/2 emarginate and bearing sparse brush of long hair-like setae. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 64).

Etymology. Named in reference to the known geographical distribution.

Distribution. Currently known only from the type locality near the eastern and southern limit of Area 1; elevation 1400 m ( Fig. 450 ).

Figures

FIGURE 59. Hydraena cheesmanae, holotype, dorsal and lateral habitus, and venter.

FIGURE 62. Hydraena marawaka, holotype, dorsal and lateral habitus, and venter.

FIGURES 447–450. Geographical distributions of Hydraena species.

FIGURES 60–61. Aedeagi of holotypes. 60. H. remulipes. 61. H. cheesmanae.