Hydraena fundarca, 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 : 137-138

Hydraena fundarca , new species

( Figs. 254 , 256 , 417 , 551 )

Type Material. Holotype (male): Eastern Highlands Province: Okapa , under wet leaves left by receding pond, 1524 m, 6° 32' S, 145° 37' E, 10 ii 1965, M. E. Bacchus (MEB 190) ( NHM) . Paratypes (28): Eastern Highlands Province: Aiyura , creek, 1670 m, 6° 21.131' S, 145° 54.398' E, 20 v 2006, John & Balke ( PNG 70) (2 ZSM) ; Frigano , Mt. Michael, in bush stream, [GE est.] 1600–1700 m, 6° 25' S, 145° 20' E, 1–30 vii 1975, R. W. Hornabrook (2 NMNZ) ; Kainantu , Yoginofi, 1900 m, 6° 21.799' S, 145° 45.463' E, 9 v 2006, Balke & Sagata ( PNG 55) (6 MCZ, NHM, NMW, PNG, ZSM) ; Okapa , under wet leaves left by receding pond, 1524 m, 6° 32' S, 145° 37' E, 10 ii 1965, M. E. Bacchus (MEB 190) (15 NHM) ; Madang Province: Finisterre Mts. , Naho River Valley, Damanti, ex small pool, probably permanent, in clay in dense shade, 1067 m, 5° 55' S, 145° 58' E, 8 x 1964, M. E. Bacchus (MEB 39) (1 NHM) ; Western Highlands Province: Kurumul , 6 km SW Kudjip, 1580 m, 5° 53.426' S, 144° 36.6' E, 13 vi 2006, John ( PNG 78) (2 ZSM) .

Differential Diagnosis. Similar in dorsal habitus to H. photogenica ( Figs. 254 , 258 ); dorsally differing therefrom in slightly more angulate sides of the pronotum and slightly more widely rounded elytral apices. The metaventral plaques differ distinctively in the two species: in H. fundarca the plaques are more widely separated, longer, more arcuate, and markedly carinate posteriorly. In addition, P2 is wider in H. fundarca than in H. photogenica (plaque ratios ca. 5/2/10/7 vs. 4/1/6/4). Males of H. fundarca are immediately recognized by the markedly modified protibiae and the markedly arcuate metatibiae. The male genitalia of the two species bear some general resemblance, but differ distinctively in many details ( Figs. 256 , 260 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.64/0.72; head 0.25/0.39; pronotum 0.39/0.57, PA 0.45, PB 0.54; elytra 0.98/0.72.

Dorsum of head dark brown, clypeus and labrum slightly lighter; pronotum light brown to testaceous around brown, diffusely margined, rectangular macula, ratios of color bands, as measured in midline, ca. 8/12/5; elytra brown; legs light brown; maxillary palpi testaceous, tip not darker. Dorsum weakly shining.

Frons punctures ca. 1xef, smaller and sparser medially; interstices shining, 1–4xpd. Clypeus effacedly microreticulate laterally, very finely sparsely punctulate and shining medially. Mentum very sparsely very finely punctulate, shining. Postmentum effacedly microreticulate in shallow median depression, otherwise finely sparsely punctate. Genae very slightly raised, shining, with shallow, obsolete median impression, without posterior ridge. Pronotum transverse, ca. median 3/4 of anterior margin slightly arcuate to posterior, sides arcuate, slightly emarginate both in front of and behind widest point, more so behind; punctures on disc larger than largest frons punctures, interstices strongly shining, ca. 2–4xpd, punctures anteriorly and posteriorly slightly larger than those on disc; PF1 and PF4 absent; PF2 very shallow, obsolete, nearly absent; PF3 moderately deep, wide.

Elytra with summit of posterior declivity at or very near midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd of 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. 5/2/10/7. P1 laminate; median carina nearly straight in profile, very slightly arcuate between coxae. P2 markedly concave, length/width ca. 7/5, sides slightly diverging toward blunt, slightly raised apex. Plaques slightly arcuate, transversely lowly rounded anteriorly, becoming markedly carinate posteriorly, at sides of median depression. Metaventrite between mesocoxae very slightly raised. AIS width at straight posterior margin ca. 1.5x P2. All legs of moderate length, moderately stout. Profemur (male) with small tubercle on ventral margin near basal 1/3; protibia markedly modified, straight, widened on antero- and posteromedial margins forming sharp ridges, margin from widest point to apex tapering and each bearing row of short spines, medial surface concave between ridges. Mesotibia straight. Metatibia arcuate, slender, width quite uniform over total length. Abdominal apex symmetrical; last tergite (male) with apicomedian notch. Aedeagus as illustrated ( Fig. 256 ). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 417 ).

Etymology. Named in reference to the arcuate metatibiae of the males, and to the relationship to H. funda .

Distribution. Currently known from several localities in the eastern part of Area 1 (1524–1900 m), and one locality on the other side of the lowlands, in the Finisterre Mts. at the border of Areas 5 and 3 (1067 m) ( Fig. 551 ). This is one of ten species with distributions exclusively shared between Areas 1 and 5 ( Fig. 422 ).

Figures

FIGURE 254. Hydraena fundarca, holotype, dorsal and lateral habitus, and venter.

FIGURE 258. Hydraena photogenica, holotype, dorsal and lateral habitus, and venter.

FIGURES 256–257. Aedeagi of holotypes. 256. H. fundarca. 257. H. fundapta.

FIGURES 416–419. Female tergite X, gonocoxite, and spermatheca of Hydraena species.

FIGURES 551–554. Geographical distributions of Hydraena species.

FIGURES 260–261. Aedeagi of holotypes. 260. H. photogenica. 261. H. torricellica.

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.