Hydraena buloba, 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 : 105

Hydraena buloba , new species

( Figs. 182, 184, 518)

Type Material. Holotype (male): Morobe Province: Herzog Mts., Vagau [Wagau], ex shallow pools in marsh, 1128 m, 6° 48' S, 146° 48' E, 8 i 1965, M. E. Bacchus (MEB 144) ( NHM).

Differential Diagnosis. Recognized from the two other members of the Luridipennis group in PNG by the more robust body, the more markedly angulate sides of the very transverse pronotum (PL/PW ca. 0.50), and the striate-impressed elytral series ( Figs. 178, 179, 182). The pro- and metatibiae of males differ in all three species, and the male genitalia distinctively differ ( Figs. 180, 181, 184).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.20/0.98; head 0.30/0.48; pronotum 0.49/0.75, PA 0.55, PB 0.64; elytra 1.43/0.98. Dorsum of head and pronotal disc piceous, remainder of dorsum dark brown; legs and maxillary palpi brown.

Frons punctures ca. 2–3xef; interstices shining, narrow walls to 1xpd. Clypeus laterally microreticulate and as coarsely punctate as frons, medially less coarsely punctate. Mentum shining, finely sparsely punctate; postmentum medially microreticulate, otherwise finely sparsely punctate, shining. Genae raised, lacking posterior ridge, midlongitudinally impressed. Pronotum densely coarsely punctate, punctures on disc deep, ca. 3–4xpd those of frons, interstices narrow walls to 1xpd, some interstices uniting to form short longitudinal lines; PF1 shallow, in midline extended to ca. midlength of pronotum; PF2 deep, oval, oblique; PF3 and PF4 deep, shallowly joined.

Elytral punctures striate-impressed, ca. 1.5xpd of largest pronotal punctures. Intervals slightly raised, width ca. 1xpd, interstices between punctures of a row less, some punctures contiguous. Explanate margin wide. Apices in dorsal aspect separately rounded, in posterior aspect margins forming angle with one another.

Metaventral disc densely punctate beneath hydrofuge pubescence, plaques very small, oval, located basolaterally on sides of deep, inverted V-shaped median depression. P1 laminate; median carina angulate in profile. P2 very narrow, l/w ca. 5/3, sides parallel, apex blunt. No carina between mesoventral intercoxal process and median depression. AIS flat, width at slightly arcuate posterior margin 3x P2. Abdominal apex asymmetrical, with short setae; last tergite notched on ventral face. Protrochanter weakly keeled. Protibia straight, slightly widened on medial margin at about distal 1/3. Mesotibia straight. Metafemur with brush of long setae on entire length of lower surface. Metatibia straight, medial margin slightly widened in distal 1/2, dorsomedian margin with brush of setae in distal 1/2. Aedeagus as illustrated ( Fig. 184).

Etymology. Named in reference to the large rounded lobes of the aedeagus.

Distribution. Currently known only from the type locality in the Herzog Mts. of Area 6; elevation 1128 m ( Fig. 518).