Hydraena colorata, 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 : 59-60

Hydraena colorata , new species

( Figs. 87 , 89 , 316–318 , 398, 471 )

Type Material. Holotype (male): Morobe Province: 5 miles W of Lae, Buins Creek , ex sand and gravel banks of clear fast river, [GE est.] 10–40 m, 6° 43' S, 147° 2' E, 28 xii 1965, M. E. Bacchus (MEB 121) ( NHM) . Paratypes (30): Madang Province: 5 km NW CRI, Nagada Harb , [GE est.] 10–30 m, 5° 20' S, 145° 42' E, 18 iii 1991, D. Larson (2 MCZ) ; Gogal Valley , 4 km S Baru Village, [GE est.] 300–500 m, 5° 42' S, 146° 32' E, 10 iv 1991, D. Larson (2 MCZ) ; Ramu Valley , 2 km SE Brahman, [GE est.] 130–150 m, 5° 43' S, 145° 22' E, 18 iv 1991, D. Larson (1 MCZ) ; Sepik Ramu Basin, Kojé Creek , unshaded creek, small to medium cobbles, gravel and fine sand (the latter in areas of slack water), filamentous algae on stony substrates, small accumulations of leaf litter, 160 m, 5° 33' S, 145° 23' E, 1 vii–30 viii 1988, D. Dudgeon (1 NMW) ; Morobe Province: Same data as holotype (9 NHM) ; Herzog Mts., Bundun , 700–800 m, 6° 51.598' S, 146° 37.07' E, 2 iv 2006, Balke & Sagata ( PNG 27) (6 MCZ, NHM, NMW, PNG, ZSM) ; Herzog Mts., Bundun , beating leaves, 700–800 m, 6° 51.598' S, 146° 37.07' E, 2 iv 2006, Balke & Sagata ( PNG 28) (2 ZSM) ; Sandaun Province: road Vanimo–Bewani close coast, 400–480 m, 2° 44.372' S, 141° 15.067' E, 13 iv 2006, Balke & Sagata ( PNG 41) (2 ZSM) ; Western Highlands Province: Sepik River Basin, Kil Stream , montane forest, 1800 m, 5° 40' S, 144° 42' E, 16 viii 1988, D. Dudgeon (5 NMW) .

Differential Diagnosis. Among members of the Colorata group similar to H. nanocolorata in having shallow pronotal foveae PF2 and a distinctive pronotal fascia ( Figs. 87 , 98 ); distinguished therefrom by the larger size (ca. 1.25 vs. 1.15 mm), the differently shaped pronotum (PA and PB equal), the proportionally longer elytra, and the slightly denser dorsal punctation. The pronotal fasciae also differ in the two species, the color band ratios being ca. 7/10/ 5 in H. colorata and ca. 6/9/ 4 in H. nanocolorata . The male genitalia of the two species distinctively differ ( Figs. 89 , 100 ). The metaventrite, abdominal apex, and very complicated chaetotaxy of the tibiae are illustrated with SEMs ( Figs. 316–318 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.25/0.54; head 0.19/0.29; pronotum 0.31/0.39, PA 0.33, PB 0.33; elytra 0.77/0.54. Dorsum of head piceous; pronotum testaceous in front of and behind piceous fascia, ratios of color bands, as measured in midline, ca. 7/10/5; elytra brown; legs light brown to testaceous; maxillary palpi testaceous.

Frons punctures ca. 1xef; interstices weakly shining, 1–3xpd. Clypeus microreticulate laterally, very finely sparsely punctate medially. Mentum and anterior 2/3 of postmentum very sparsely and very finely punctulate, strongly shining; posterior 1/3 of postmentum with much larger punctures. Genae raised, shining, without posterior ridge. Pronotum weakly cordiform, anterior margin emarginate; punctures on disc ca. 1xpd of largest frons punctures, interstices shining, 2–4xpd, punctures larger and denser at anterior and posterior; PF1 united to form very shallow transverse impression across anterior 1/3 of pronotal disc; PF2 shallow, oval, oblique, very shallowly confluent; PF3 moderately deep; PF4 obsolete.

Elytra with summit of posterior declivity slightly before midlength; lateral explanate margins narrow; on basal 1/3 punctures slightly larger than 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. 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. 3/1/4/4. P1 laminate; median carina sinuate in profile. P2 raised, l/w ca. 2/1, sides slightly converging toward apex. Plaques short, carinate, located at sides of deep, inverted V-shaped median depression. Metaventrite with very low midlongitudinal ridge between P2 and apex of median depression. AIS slightly concave, width at straight posterior margin ca. 1.5x P2. Profemur (male) with small, sharply pointed tubercle next to trochanter; protibia very slightly thickened in distal 1/2. Mesotibia straight. Metatibia straight, medial margin in distal 1/3 with few recumbent hair-like setae. Abdominal apex symmetrical; last tergite (male) deeply notched. Aedeagus as illustrated ( Fig. 89 ). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 398).

Etymology. Named in reference to the dorsal coloration.

Distribution. Currently known from Areas 2–6, at an elevation range of 10–800 m, and one perhaps questionable locality in Area 1, at 1800 m ( Fig. 471 ).

Figures

FIGURE 87. Hydraena colorata, holotype, dorsal and lateral habitus, and venter.

FIGURE 98. Hydraena nanocolorata, holotype, dorsal and lateral habitus, and venter.

FIGURES 88–89. Aedeagi of holotypes. 88. H. koma. 89. H. colorata.

FIGURES 316–321. Scanning electron micrographs of H. colorata (316–317) and H. paxillipes (318–321).

FIGURES 471–474. Geographical distributions of Hydraena species.

FIGURES 100–101. Aedeagi of holotypes. 100. H. nanocolorata. 101. H. clarinis.