Hydraena cristatigena Jäch & Díaz, 2000

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 : 92-93

Hydraena cristatigena Jäch & Díaz, 2000

( Figs. 158 , 160 , 343–345 , 503 )

Hydraena cristatigena Jäch & Díaz, 2000: 50 .

Type material. Holotype (male): Indonesia: Papua Province: Bime–Calab Gebiet Bime [labels: " IRIAN JAYA: 22.9.1993 Bime–Calab Gebiet Bime, 1400 m // ca. 140°12' E 04°20'S, leg. M. Balke (16) // HOLOTYPUS Hydraena cristatigena sp. n. des. Jäch & Díaz 2000 "] ( NMW).

Differential Diagnosis. Among members of the Cristatigena group, quite similar in dorsal habitus to H. variopaca ( Figs. 158 , 159 ); differing therefrom by the slightly smaller size (ca. 1.81 vs. 1.88 mm) and the more narrowly spaced metaventral plaques. Males are additionally recognized by the slightly widened hind tibiae. The male genitalia of the two species differ in significant details, while in general shape suggest a rather close relationship ( Figs. 160, 161 ). The metaventrite and leg chaetotaxy are illustrated with SEMs ( Figs. 343–345 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.80/0.81; head 0.29/0.44; pronotum 0.41/0.56, PA 0.48, PB 0.44; elytra 1.10/0.81. Dorsum brown to dark brown, head and pronotal disc slightly darker, palpi light brown, except distal 1/2 of last palpomere darker.

Dorsum of head and pronotum densely punctulate, dull; punctures of frons disc and pronotal disc ca. 1xef, interstices ca. 1xpd or slightly larger; punctures of clypeus obsolete. Labrum apicomedially excised, free margins rounded on each side of excision, weakly upturned. Mentum sparsely punctate, dull; postmentum densely micropunctulate. Genae raised, posterior ridge strong. Pronotum with anterior margin weakly emarginate over middle 1/ 2; all pronotal foveae moderately deep.

Elytra dull, punctures 1–2xpd of largest pronotal punctures, most punctures with three granules, one at anterior margin and one on each side. Intervals not raised, width ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins not forming angle with one another. Explanate margin well developed, about as wide as widest part of metatibia.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 4/1/7/8. P1 laminate; median carina sinuate in profile. P2 moderately narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques very narrow, weakly raised, carinate, located at lateral margins of deep, median depression. Metaventrite tumid lateral to plaques. No midlongitudinal carina between mesoventral intercoxal process and plaques. Hydrofuge pubescence dense. AIS flat, width at straight posterior margin ca. 1.5x P2. Protibia (male) widened, medial surface rather flat; mesotibia simple; metatibia with medial surface slightly widened near midlength. Abdominal apex symmetrical.

Aedeagus ( Fig. 160 ) main piece with large distal lobe, in ventral aspect lobe apically pointed, with arcuate right side, left side with small indentation demarcating tiny lobe; left paramere small, not bilobed, setae in two clusters; right paramere sharply rounded apically; distal piece, in right lateral view, with knob-like lobe. The aedeagus of the holotype, and the spermatheca, have been illustrated by Jäch and Díaz (2000).

Distribution. Horizontally, a very widely distributed species with an equally wide vertical range of 20–2200 m. Specimens have been collected from Areas 1, 2, 3 (perhaps), 5, 7, and 11 ( Fig. 503 ). Notably, this "common" species was not collected during the large rotenone study of Kojé Creek, in eastern Area 3; this locality is "surrounded" by other sites where this species has been collected.

Additional material (826): Central Province: nr. Port Moresby, Sogeri Plateau, Musgrave River , ex gravel banks, [GE est.] 100–200 m, 9° 46' S, 147° 41' E, 16 iii 1965, M. E. Bacchus (MEB 200a) (3 NHM) ; nr. Port Moresby, Sogeri Plateau, Musgrave River , river, [GE est.] 100–200 m, 9° 46' S, 147° 41' E, 16 iii 1965, M. E. Bacchus (MEB 200) (13 NHM) ; Tapini , 870 m, 8° 20.511' S, 146° 59.824' E, 29 x 2007, Kinibel ( PNG 161) (34 MCZ, NHM, NMW, PNG, ZSM) ; Eastern Highlands Province: below Yonki , 850 m, 6° 11.332' S, 146° 3.052' E, 4 iv 2006, Balke & Sagata ( PNG 31) (99 MCZ, NHM, NMW, PNG, ZSM) ; Kami River , Goroka , Eastern Highlands, [GE est.] 2000–2200 m, 6° 5' S, 145° 23' E, 23 vii 1965, R. W. Hornabrook (2 NMNZ) ; Mjairasa, Okapa , ex stones in waterfall spray, [GE est.] 1500–1700 m, 6° 32' S, 145° 37' E, 17 iii 1965, R. W. Hornabrook (1 NMNZ) ; NE, Bena River , 1500 m, 6° 0' S, 145° 36' E, 30 viii 1971, J. Sedlacek (3 BPBM) ; Okapa , ex muddy gravel banks of fast, clear stream, 1524 m, 6° 32' S, 145° 37' E, 9 ii 1965, M. E. Bacchus (MEB 183) (1 NHM) ; Okapa , on wet rocks above waterline, fast, clear stream, 1524 m, 6° 32' S, 145° 37' E, 9 ii 1965, M. E. Bacchus (MEB 183a) (6 NHM) ; Okapa , under stones in small river, 1524 m, 6° 32' S, 145° 37' E, 10 ii 1965, M. E. Bacchus (MEB 186) (1 NHM) ; same locality, 10 ii 1965, M. E. Bacchus (MEB 187) (6 NHM) ; Purosa Valley, nr. Okapa , on submerged stones, [GE est.] 1500–1700 m, 6° 32' S, 145° 37' E, 8 ii 1965, M. E. Bacchus (MEB 182a) (2 NHM) ; Wanitabi Valley, nr. Okapa , ex dead leaves caught among rocks in small swift river, 1372 m, 6° 32' S, 145° 37' E, 5 ii 1965, M. E. Bacchus (MEB 171b) (1 NHM) ; Wanitabi Valley, nr. Okapa , on wet rocks above waterline in small swift river, 1372 m, 6° 32' S, 145° 37' E, 5 ii 1965, M. E. Bacchus (MEB 171c) (31 NHM) ; Gulf Province: Marawaka, near Ande , 1000 m, 7° 3.598' S, 145° 44.375' E, 10 xi 2006, Balke & Kinibel ( PNG 89) (3 ZSM) ; Madang Province: Finisterre Mts., Lower Naho Valley, Hinggia , ex rocks and gravel bank of swift clear stream, 762 m, 5° 50' S, 146° 7' E, 28 xi 1964, M. E. Bacchus (MEB 112) (22 NHM) ; Finisterre Mts., Naho River Valley, Damanti , ex gravel banks of very fast-running clear stream, 914 m, 5° 55' S, 145° 58' E, 11 x 1964, M. E. Bacchus (MEB 47) (10 NHM) ; Keki, Adelbert Mts. , 400 m, 4° 43.058' S, 145° 24.437' E, 29 xi 2006, Binatang Boys ( PNG 119) (37 MCZ, NHM, NMW, PNG, ZSM) ; Simbai area , 1200 m, 5° 13.389' S, 144° 37.285' E, 10 iii 2007, Kinibel ( PNG 152) (13 MCZ, NHM, NMW, PNG, ZSM) ; Morobe Province: ca. 10 km S Garaina Saureri , 1600 m, 7° 55' S, 147° 5' E, 24 iii 1998, A. Riedel (1 NMW) ; Lae, Umg. [=environs of] Gebensis , Gorogias River , [GE est.] 20–30 m, 6° 44' S, 147° 0' E, 14 vi 1979, W. G. Ullrich (2 MHNG) ; Sandaun Province: Mianmin , 670 m, 4° 53.329' S, 141° 35.263' E, 22 x 2008, S. Ibalim ( PNG 189) (58 MCZ, NHM, NMW, PNG, ZSM) ; Mianmin [Miyanmin], [GE est.] 700–800 m, 4° 54' S, 141° 36' E, 19–21 v 1998, A. Riedel (272 NMW) ; Mianmin , pool, 990 m, 4° 54.57' S, 141° 35.49' E, 23 x 2008, S. Ibalim ( PNG 193) (50 MCZ, NHM, NMW, PNG, ZSM) ; Mianmin , river, 700 m, 4° 52.858' S, 141° 31.706' E, 21 x 2008, S. Ibalim ( PNG 197) (10 MCZ, NHM, NMW, PNG, ZSM) ; Mianmin , river, 1080 m, 4° 55.78' S, 141° 38.185' E, 24 x 2008, S. Ibalim ( PNG 195) (32 MCZ, NHM, NMW, PNG, ZSM) ; Ofektamin , 820 m, 5° 4.113' S, 141° 35.841' E, 17 x 2008, S. Ibalim ( PNG 190) (43 MCZ, NHM, NMW, PNG, ZSM) ; S Mianmin, [GE est.] 900–1100 m, 4° 54' S, 141° 36' E, 20 v 1998, A. Riedel (2 NMW) ; S Mianmin, stream, 700 m, 4° 54' S, 141° 36' E, 19 v 1998, A. Riedel (41 NMW) ; Southern Highlands Province: Tari to Koroba , 1600 m, 5° 46.5' S, 142° 50' E, 15 v 2006, Balke ( PNG 65) (9 MCZ, NHM, NMW, PNG, ZSM) ; Western Highlands Province: Sepik-Ramu Basin, Inonake Stream , runs and small rapids among boulders, runs with cobbles, gravel and sand, partially shaded, 1320 m, 5° 40' S, 144° 42' E, 1 vii–30 viii 1988, D. Dudgeon (18 NMW) .

Figures

FIGURE 158. Hydraena cristatigena, holotype, dorsal and lateral habitus, and venter.

FIGURE 159. Hydraena variopaca, holotype, dorsal and lateral habitus, and venter.

FIGURES 160–161. Aedeagi. 160. H. cristatigena, non-type specimen from E. Highlands, Wanatabe Valley, nr. Okapa. 161. H. variopaca, holotype.

FIGURES 340–345. Scanning electron micrographs of H. bacchusi (340–341), H. variopaca (342) and H. cristatigena (343– 345).

FIGURES 503–506. Geographical distributions of Hydraena species.