Hydraena aulaarta, 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 : 56

Hydraena aulaarta , new species

( Figs. 82 , 84 , 463 )

Type Material. Holotype (male): Western Highlands Province: Kundum , 1400 m, 5° 16.096' S, 144° 27.869' E, 3 iii 2007, Kinibel ( PNG 142) ( ZSM) . Paratypes (19): Madang Province: Simbai area , 1200 m, 5° 13.389' S, 144° 37.285' E, 10 iii 2007, Kinibel ( PNG 152) (2 ZSM) ; Sandaun Province: Dogman River , ex surface of rocks, 2054 m, 4° 55.789' S, 141° 38.202' E, 15 xi 2003, K. Sagata (WB 21) (1 ZSM) ; May River , ex river side pool, 970 m, 4° 49.779' S, 141° 38.174' E, 19 x 2003, K. Sagata (WB 41) (1 ZSM) ; Western Highlands Province: Same data as holotype (13 MCZ, NHM, NMW, PNG, ZSM) .

Differential Diagnosis. Similar to H. insandalia in habitus and some male sexual dimorphisms (tubercle on first abdominal ventrite ( Figs. 74 , 82 ); differing therefrom by the smaller size (ca. 1.64 vs. 1.81 mm), the flat plaques, and, in males, the differently shaped pro- and metatibiae, and the meso- and metatarsi with long hair-like setae. Some of these differences are subtle; reliable determinations of the two species will require examination of the aedeagi, which distinctively differ ( Figs. 76 , 84 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.64/0.68; head 0.25/0.39; pronotum 0.40/0.48, PA 0.42, PB 0.39; elytra 1.01/0.68. Dorsum piceous; legs and maxillary palpi dark brown.

Frons punctures ca. 1xef, slightly larger near eyes than medially; interstices shining, 1–6xpd. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum very sparsely very finely punctulate, shining; postmentum densely micropunctulate, dull, except anterior margin shining. 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, 2–6xpd, 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 slightly past 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. 2–3xpd, as are interstices between punctures of a row, a few punctures subserial. 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. 3/4/12/1. P1 laminate; median carina sinuate in profile. P2 raised, l/w ca. 2/1, sides slightly converging toward blunt apex. Plaques very large, very narrowly separated, slightly more narrowly separated posteriorly than anteriorly, weakly raised. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin ca. 2x P2. All legs long and very slender. Profemur (male) with small, sharply pointed tubercle next to trochanter. Protibia appearing compressed at ca. distal 1/3, then roundly widened on anterior surface, moderately long spine on medial surface at base of widened area. Mesotibia very slightly arcuate, medial margin slightly flattened. Metatibia very slightly arcuate. Meso- and metatarsi with moderately long setae along lower margin that lie flat on cuticle. Fifth abdominal ventrite simple. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 84 ).

Etymology. "Furrow narrow"; named in reference to the narrowly separated metaventral plaques.

Distribution. Currently known from Area 1, near the northern margin; elevation range 970–2054 m, with the only record below 1200 m being 970 m at the Mianmin area ( Fig. 463 ).

Figures

FIGURE 74. Hydraena insandalia, holotype, dorsal and lateral habitus, and venter.

FIGURE 82. Hydraena aulaarta, holotype, dorsal and lateral habitus, and venter.

FIGURES 84–85. Aedeagi of holotypes. 84. H. aulaarta. 85. H. altapapua.

FIGURES 463–466. Geographical distributions of Hydraena species.

FIGURES 76–77. Aedeagi of holotypes. 76. H. insandalia. 77. H. biundulata.