Hydraena pegopyga, 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 : 144-145

Hydraena pegopyga , new species

( Figs. 270 , 272 , 419 , 538 )

Type Material. Holotype (male): Madang Province: Ramu Valley , 3 km N Brahman, [GE est.] 130–150 m, 5° 40' S, 145° 22' E, 16 v 1991, D. Larson ( MCZ) . Paratypes (131): East Sepik Province: Amboin Patrol Post , Karawari Lodge, [GE est.] 20–100 m, 4° 37' S, 143° 29' E, 7 ii 1983, A. C. Messer (4 USNM) ; same locality, 26 iii 1983, A. C. Messer (2 USNM) ; Madang Province: Adelbert Mts. , Keki to Sewan, 650 m, 4° 41.802' S, 145° 25.46' E, 7 v 2006, Balke ( PNG 54) (9 MCZ, NHM, NMW, PNG, ZSM) ; Akameku– Brahmin , Bismarck Range, 250–500 m, 5° 47.026' S, 145° 24.131' E, 25 xi 2006, Balke & Kinibel ( PNG 115) (12 MCZ, NHM, NMW, PNG, ZSM) ; Baiteta , [GE est.] 100–200 m, 5° 1' S, 145° 45' E, 13 iii 1991, D. Larson (5 MCZ) ; Keki , Adelbert Mts., 400 m, 4° 43.058' S, 145° 24.437' E, 29 xi 2006, Binatang Boys ( PNG 119) (6 MCZ, NHM, NMW, PNG, ZSM) ; near Brahmin , 200 m, 5° 47.026' S, 145° 24.131' E, 25 xi 2006, Balke & Kinibel ( PNG 116) (7 MCZ, NHM, NMW,

PNG, ZSM); Ramu Valley , 3 km N Brahman, [GE est.] 130–150 m, 5° 40' S, 145° 22' E, 16 v 1991, D. Larson (32 MCZ) ; Morobe Province: Torricelli Mts. , village below Sibilanga Stn. , 400 m, 3° 26.75' S, 142° 29.949' E, 18 iv 2006, Balke ( PNG 42) (6 MCZ, NHM, NMW, PNG, ZSM); National Capital District, Varirata NP, 600 m, 9° 26.13' S, 147° 22.09' E, 16 xii 2007, Balke & Sagata ( PNG 159) (22 MCZ, NHM, NMW, PNG, ZSM); Sandaun Province: Bewani Stn., forest puddles at base of Bewani Mts., 300 m, 3° 5.13' S, 141° 10.227' E, 12 iv 2006, Balke & Sagata ( PNG 38) (15 MCZ, NHM, NMW, PNG, ZSM); Bewani Stn., stream at base of Bewani Mts., 200– 300 m, 3° 5.13' S, 141° 10.227' E, 12 iv 2006, Balke & Sagata ( PNG 37) (7 MCZ, NHM, NMW, PNG, ZSM); Mianmin, river, 1080 m, 4° 55.78' S, 141° 38.185' E, 24 x 2008, S. Ibalim ( PNG 195) (2 ZSM) ; road Vanimo– Bewani close coast, 400–480 m, 2° 44.372' S, 141° 15.067' E, 13 iv 2006, Balke & Sagata ( PNG 41) (1 ZSM) ; Telefomin , trail to Eliptamin, 1700–1800 m, 5° 4' S, 141° 40' E, 16–17 v 1998, A. Riedel (1 NMW) .

Differential Diagnosis. Recognized by the combination of the large size (l/w ca. 1.82/ 0.86 mm), the broad body form, the basally wide pronotum (PA/PB as ca. 49/67), and, in males, the greatly enlarged abdominal apex ( Fig. 270 ). Ventrally, P2 is very wide and concave, and the metaventral plaques are carinate and equally widely separated (plaque ratios ca. 8/1/7/8). The male genitalia cannot be confused with any other PNG Hydraena ( Fig. 272 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.82/0.86; head 0.25/0.44; pronotum 0.46/0.67, PA 0.49, PB 0.67; elytra 1.12/0.86. Dorsum of head with frons dark brown to piceous, clypeus brown medially, testaceous laterally, labrum testaceous; pronotum testaceous around brown, diffusely margined, rectangular macula, ratios of color bands, as measured in midline, ca. 9/15/7; elytra dark brown; legs brown to light brown; maxillary palpi testaceous, tip not darker. Dorsum moderately shining.

Frons punctures ca. 1xef or slightly smaller near eyes, much smaller and sparser medially; interstices shining, 1–5xpd. Clypeus very finely sparsely punctulate, shining. 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 weakly arcuate, slightly emarginate in front of and behind widest part; punctures on disc ca. 2–3xpd largest frons punctures, interstices shining, ca. 1– 3xpd, punctures posteriorly slightly larger and denser than those on disc; PF1, PF2 and PF4 absent; PF3 shallow, wide.

Elytra widest at about anterior 1/3; summit of posterior declivity at or very near midlength; lateral explanate margins rather narrow; on basal 1/3 punctures slightly smaller and shallower than largest pronotal punctures, subserial to random, punctures becoming gradually smaller toward posterior. 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 deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 8/1/7/8. P1 slightly wider than laminate, ca. 1/4 P2; median carina nearly straight in profile, slightly arcuate between coxae. P2 markedly concave, length/width ca. 5/8, sides very slightly diverging toward blunt, transversely concave apex. Plaques narrow lines, anteriorly flat or weakly rounded, becoming low carinae posteriorly, converging anteriorly, at sides of median inverted V-shaped depression. Metaventrite between mesocoxae sloping, confluent with concave tip of P2. AIS width at slightly arcuate posterior margin ca. equal P2. All legs of moderate length, slender. Profemur (male) without tubercle on ventral margin; protibia straight, distal 2/3 of medial margin very slightly emarginate and flat. Meso- and metatibia straight, slen- der. Abdominal apex greatly enlarged, pygidiform, asymmetrical; last tergite (male) with oblique subapical ridge at margin of concavity. Aedeagus as illustrated ( Fig. 272 ). Female tergite X, gonocoxite, and spermatheca as illustrated ( Fig. 419 ).

Etymology. Named in reference to the very large, peg-shaped abdominal apex.

Distribution. Widely distributed both horizontally and vertically, but apparently very sparsely as far as is known. Localities are present in Areas 1–5, and Area 11; elevation range 20–1800 m ( Fig. 538 ). This is the only species that has been found in both Area 4 and Area 11.

Figures

FIGURE 270. Hydraena pegopyga, holotype, dorsal and lateral habitus, abdominal apex, and venter.

FIGURES 272–273. Aedeagi of holotypes. 272. H. pegopyga. 273. H. funda.

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

FIGURES 535–538. Geographical distributions of Hydraena species.