Hydraena maculopala Perkins 2011, new species

Hydraena maculopala, new species (Figs. 203, 205, 531) Type Material. Holotype (male): Madang Province: Madang, Ohu Village, 160 m, 5° 13.923' S, 145° 40.763' E, 30 iv 2006, Balke & Sagata (PNG 49) (ZSM). Paratypes (29): Madang Province: Adelbert Mts., Sewan –Keki, 700 m, 4° 42.215' S, 145° 25.154' E, 4 v 2006, Balke & Manaono (PNG 51) (3 ZSM); Keki, Adelbert Mts., 400 m, 4° 43.058' S, 145° 24.437' E, 29 xi 2006, Binatang Boys (PNG 119) (2 ZSM); Keki– Sewan, Adelbert Mts., 700 m, 4° 41.802' S, 145° 25.46' E, 30 xi 2006, Binatang Boys (PNG 120) (24 MCZ, NHM, NMW, PNG, ZSM). Differential Diagnosis. Similar in general dorsal coloration and pronotal shape and sculpture to H. nanopala (Figs. 203, 206); differing therefrom in larger size (ca. 1.32 vs. 1.23 mm), the presence of an ill-defined macula on the pronotum, the proportionally longer elytra (PW/EL ca. 0.58 vs. 0.63, and the slightly more widely separated plaques (ratios ca. 4/1/5/5 vs. 4/1/5/4). Among Pala group members, the mesoventral intercoxal process (P2) is the narrowest in these two species. They also show a similarity in basic aedeagal plan, while differing distinctively in details of the distal piece (Figs. 205, 208); reliable determinations will require examination of the aedeagi. Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.32/0.58; head 0.23/0.32; pronotum 0.32/0.45, PA 0.35, PB 0.35; elytra 0.78/0.58. Dorsum with frons dark brown to piceous; clypeus brown; labrum testaceous; pronotum testaceous around light brown, ill-defined macula; elytra brown; legs light brown to testaceous; maxillary palpi testaceous, tip not darker. Frons punctures ca. 1–2xef, slightly larger near eyes than medially; interstices shining, 1–3xpd. 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, ca. median 3/4 of anterior margin arcuate to posterior; punctures on disc ca. 1xpd frons punctures, interstices shining, 1–3xpd, punctures slightly larger and denser at anterior and posterior; PF1 very shallow, obsolete; PF2 moderately deep; 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, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–3xpd, 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. 4/1/5/5. P1 ca. 1/2 P2; median carina straight in profile; postcoxal process medially concave. P2 transversely concave, l/w ca. 5/4, sides slightly diverging toward blunt apex. Plaques very narrow, carinate, converging slightly anteriorly, at sides of deep median depression. Metaventrite concave between P2 and plaques. AIS width at straight posterior margin ca. 1.5x P2. All legs moderately long and slender. Profemur (male) with very small tubercle next to trochanter; protibia slightly arcuate, gradually increasing in width from base to apex. Meso- and metatibia straight. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated (Fig. 205). Etymology. This species is the only member of the Pala group with a pronotal macula. Distribution. Currently known from three localities in the northwestern part of Area 5; elevation range 160– 700 m (Fig. 531).Published as part of 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, pp. 1-417 in Zootaxa 2944 (1) on pages 114-115, DOI: 10.11646/zootaxa.2944.1.1, http://zenodo.org/record/528342