Hydraena owenobesa, 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 : 86-87

Hydraena owenobesa , new species

( Figs. 146 , 148 , 407 , 501 )

Type Material. Holotype (male): Morobe Province: ca. 10 km S Garaina Saureri , 1600 m, 7° 55' S, 147° 5' E, 24 iii 1998, A. Riedel ( NMW) . Paratypes: Same data as holotype (17 NMW) .

Differential Diagnosis. Similar in size (ca. 1.45 mm) and body proportions to H. reticulobesa ( Figs. 143 , 146 ); differentiated therefrom by the less markedly microreticulate pronotal disc, the shallower pronotal impressions, the larger metaventral plaques (ratios ca. 1/1/5/4 vs. 1/1/2/4), and the wider and slightly shorter P2. The aedeagi of the two species have some general plan similarities, but distinctively differ in many details ( Figs. 145 , 148 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.45/0.61; head 0.23/0.34; pronotum 0.33/0.49, PA 0.39, PB 0.40; elytra 0.89/0.61. Dorsum dark brown to piceous; legs brown; maxillary palpi light brown to testaceous, tip not darker.

Frons punctures ca. 1xef, slightly larger and denser near eyes than medially; interstices microreticulate and dull laterally, effacedly microreticulate and weakly shining medially, 1–3xpd. Clypeus microreticulate laterally, effacedly microreticulate medially, finely, sparsely punctate medially. Mentum and postmentum very sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Pronotum transverse (PL/PW ca. 0.67), ca. median 3/5 of anterior margin very slightly emarginate; moderately coarsely, densely punctate, punctures on disc ca. 2xpd frons punctures, interstices on disc effacedly microreticulate, weakly shining, 1–2xpd, interstices microreticulate and dull in impressions, punctures denser at anterior and posterior; PF1 shallow, obsolete; PF2 shallow; PF3 moderately deep; PF4 shallow.

Elytra with summit of posterior declivity slightly anterior to midlength; lateral explanate margins narrow; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, weakly shining, on disc ca. 1–2xpd, as are interstices between punctures of a row. 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. 1/1/5/4. P1 laminate; median carina sinuate in profile. P2 very narrow, raised slightly at tip, l/w ca. 6/1, sides slightly converging toward apex. Plaques very narrow, not raised, anteriorly tapering to point and converging slightly, at sides of median depression, depression does not continue to tip of P2. Metaventrite without midlongitudinal ridge. AIS width at straight posterior margin ca. 4xP2. All legs rather short, femora moderately robust. Profemur (male) without tubercle next to trochanter; protibia widest slightly past midlength, medial margin very slightly emarginate, lateral margin arcuate and bearing short stout spines in widest part. Mesotibia straight, lateral margin slightly arcuate, lateral and ventral margins each bearing row of short stout spines. Metatibia straight, medial margin in distal 2/3 weakly emarginate and with few moderately long setae, lateral margin with some short spines in distal 1/2. Abdominal apex symmetrical; last tergite (male) notched. Aedeagus as illustrated ( Fig. 148 ). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 407 ).

Etymology. Named in reference to its geographic distribution in the Owen Stanley Range, and its placement in the Spinobesa group.

Distribution. Currently known only from the type locality near Garaina Saureri in Area 7; elevation 1600 m ( Fig. 501 ).

Figures

FIGURE 143. Hydraena reticulobesa, holotype, dorsal and lateral habitus, and venter.

FIGURE 146. Hydraena owenobesa, holotype, dorsal and lateral habitus, and venter.

FIGURES 148–149. Aedeagi of holotypes. 148. H. owenobesa. 149. H. saluta.

FIGURES 404–407. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 499–502. Geographical distributions of Hydraena species.

FIGURES 144–145. Aedeagi of holotypes. 144. H. spinobesa. 145. H. reticulobesa.