Hydraena fascinata, 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 : 74-75

Hydraena fascinata , new species

( Figs. 122 , 124, 402 , 487 )

Type Material. Holotype (male): Madang Province: Finisterre Mts., Naho River Valley, nr. Moro , ex dead leaves and muddy gravel by small stream, 1372 m, 5° 50' S, 146° 7' E, 5 xi 1964, M. E. Bacchus (MEB 88) ( NHM) . Paratypes (143): Eastern Highlands Province: Marawaka , Ande, 1700–1800 m, 7° 1.697' S, 145° 49.807' E, 9 xi 2006, Balke & Kinibel ( PNG 87) (35 MCZ, NHM, NMW, PNG, ZSM) ; Madang Province: Finisterre Mts. , Naho River Valley, Budemu, ex sand and gravel banks of small stream, but only in the 20 yards that it is permanent, 1264 m, 5° 56' S, 146° 40' E, 19 x 1964, M. E. Bacchus (MEB 62) (13 NHM) ; Finisterre Mts. , Naho River Valley, Budemu –Kikipei track, ex gravel bank of small river in places where rotten leaves had accumulated, 1220 m, 5° 56' S, 146° 40' E, 24 x 1964, M. E. Bacchus (MEB 73) (6 NHM) ; Finisterre Mts. , Naho River Valley, Budemu –Kikipei track, ex gravel banks of small stream, 1220 m, 5° 56' S, 146° 40' E, 24 x 1964, M. E. Bacchus (MEB 74) (9 NHM) ; Finisterre Mts. , Naho River Valley, Moro, 1691 m, 5° 50' S, 146° 7' E, 30 x–23 xi 1964, M. E. Bacchus (MEB 78) (49 NHM) ; Finisterre Mts. , Naho River Valley, Moro, ex muddy gravel banks of small stream, 1691 m, 5° 50' S, 146° 7' E, 3 xi 1964, M. E. Bacchus (MEB 83) (7 NHM) ; Finisterre Mts. , Naho River Valley, nr. Moro, ex dead leaves and muddy gravel by small stream, 1372 m, 5° 50' S, 146° 7' E, 5 xi 1964, M. E. Bacchus (MEB 88) (7 NHM) ; Finisterre Mts. , Naho River Valley, nr. Moro, ex gravel banks of small fast stream, 1432 m, 5° 50' S, 146° 7' E, 7 xi 1964, M. E. Bacchus (MEB 91) (10 NHM) .

Differential Diagnosis. Similar in dorsal habitus to H. aquila ; differentiated therefrom by the larger size (ca. 1.76 vs. 1.56 mm), the more elongate elytra, the less coarsely punctate dorsum, and the more narrowly spaced plaques ( Figs. 122 , 123 ). The male genitalia of the two species distinctively differ ( Figs. 124, 125).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.76/0.73; head 0.28/0.39; pronotum 0.39/0.51, PA 0.42, PB 0.43; elytra 1.09/0.73. Dorsum piceous except narrow light brown to brown band along anterior margin of pronotum, occupying ca. 1/5 of pronotum as measured in midline; legs brown to dark brown; maxillary palpi brown, tip not darker. Dorsum weakly shining.

Frons punctures ca. 1xef, interstices laterally microreticulate, dull, medially shining, ca. 2–5xpd. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate and shining medially. Mentum very sparsely very finely punctulate, strongly shining. Postmentum microreticulate. Genae very slightly raised, shining, with very small, shallow, posteromedian impression, without posterior ridge. Pronotum cordiform, median 2/3 of anterior margin emarginate; sides weakly emarginate between anterior angle and widest part; punctures on disc ca. 1xpd largest frons punctures, interstices shining, ca. 2–5xpd, punctures anteriorly and posteriorly ca. 2–3xpd those on disc; PF1, PF2 and PF4 very shallow; PF3 moderately deep, wide.

Elytra widest at about midlength; summit of posterior declivity at or very near midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, a few punctures subserial, punctures becoming gradually smaller toward posterior. Intervals not raised, shining, on disc ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/3/9/2. P1 laminate; median carina sinuate in profile, slightly raised between coxae. P2 length/width ca. 2/1, transversely convex, sides parallel, apex blunt. Plaques large, slightly raised, at sloping sides of median depression, anteriorly very slightly tapering. Metaventrite between mesocoxae weakly raised in midline. AIS width at straight posterior margin slightly greater than P2. All legs rather long and slender. Profemur (male) without tubercle on ventral margin; protibia straight, medial margin subapically emarginate, appearing weakly hooked, and with few short spines in emargination. Mesotibia straight, slender. Metatibia straight, slender, medial margin extremely slightly emarginate. Abdominal apex very slightly asymmetrical; last tergite (male) with apicomedian notch and fringe of setae. Aedeagus as illustrated ( Fig. 124).Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 402 ).

Etymology. "Charm, enchant"; named in reference to the intricacy but yet clarity of the aedeagus, and to the simple but yet bold pattern of the male protibial setae.

Distribution. Currently known from far eastern Area 1 (1700–1800 m) and localities in the Finisterre Mts., Area 5 (1220–1691 m) ( Fig. 487 ). This is one of ten species with distributions exclusively shared between Areas 1 and 5 ( Fig. 422 ).

Figures

FIGURE 122. Hydraena fascinata, holotype, dorsal and lateral habitus, and venter.

FIGURE 123. Hydraena aquila, holotype, dorsal and lateral habitus, and venter.

FIGURES 400–403. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 487–490. Geographical distributions of Hydraena species.

FIGURES 421–422. 421. All known collecting localities for Papua New Guinea Hydraena. 422. Ten species, representing eight species groups, with distributions exclusively shared between Areas of Endemism 1 and 5.