Hydraena incista, 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 : 70-71

Hydraena incista , new species

( Figs. 114 , 116 , 481 )

Type Material. Holotype (male): Western Highlands Province: Simbai , Kairong River, 1850 m, 5° 14.84' S, 144° 28.457' E, 2 iii 2007, Kinibel ( PNG 139) ( ZSM).

Differential Diagnosis. Among members of the Velvetina group, somewhat similar in habitus to H. adelbertensis and H. copulata ( Figs. 110 , 114 , 115 ); all three species have the frons slightly concave. Distinguished from both species by the pronotal shape (PL=PW vs. PL<PW), and the depressed mesoventral intercoxal process. The aedeagi of the three species distinctively differ ( Figs. 112, 116, 117 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.71/0.68; head 0.27/0.37; pronotum 0.43/0.43, PA 0.37, PB 0.34; elytra 1.00/0.68. Dorsum piceous, except light brown to testaceous band across anterior 1/6 of pronotum, legs and maxillary palpi brown to reddish brown.

Frons with depressed area next to each eye, punctures less than 1xef; interstices 2–4xpd; depressed areas microreticulate, very weakly shining, disc more strongly shining,. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum slightly concave, very sparsely very finely punctulate, shining; postmentum rather coarsely punctate and effacedly micropunctulate, weakly shining. Genae raised, except medially impressed, shining, without posterior ridge. Pronotum cordiform, anterior margin slightly arcuate; punctures on disc ca. 1xef, interstices shining, 1–3xpd, punctures slightly larger and denser at anterior and posterior; PF1 shallow; PF2 deep, large, oval, oblique, confluent, together forming U-shaped impression; PF3 deep; PF4 moderately deep.

Elytra convex, 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, some punctures random near base. 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.

P1 laminate; median carina very low, not sinuate in profile. P2 not raised, very short, much shorter than and confluent with metaventral intercoxal process. Plaques absent, hydrofuge pubescence longest at sides of deep median depression. AIS width at straight posterior margin ca. 3x P2. All legs long and slender, except profemur more robust. Profemur (male) without tubercle next to trochanter; protibia straight, medial margin gradually widening from base to ca. distal 1/4, then emarginate and with flat surface to apex, widest point with large spine, emargination with row of short spines. Mesotibia straight. Metatibia straight, with few setae on medial margin subapically; metatarsi with long setae on basal tarsomeres. Abdominal apex symmetrical; last tergite (male) notched. Aedeagus ( Fig. 116 ) distal piece with several smaller processes and one large, blunt process. Female not yet known.

Etymology. "Out of the chest box"; named in reference to the very unusual, reduced condition of the mesoventral intercoxal process.

Distribution. Currently known only from the type locality, the Kairong River, in north-central Area 1; elevation 1850 m ( Fig. 481 ).

Figures

FIGURE 110. Hydraena adelbertensis, holotype, dorsal and lateral habitus, and venter.

FIGURE 114. Hydraena incista, holotype, dorsal and lateral habitus, and venter.

FIGURE 115. Hydraena copulata, holotype, dorsal and lateral habitus, and venter.

FIGURES 116–117. Aedeagi of holotypes. 116. H. incista. 117. H. copulata.

FIGURES 479–482. Geographical distributions of Hydraena species.