Hydraena reticuloides, Published, 2007

PERKINS, PHILIP D., 2007, A revision of the Australian species of the water beetle genus Hydraena Kugelann (Coleoptera: Hydraenidae), Zootaxa 1489 (1), pp. 1-207 : 14-15

Hydraena reticuloides new species

( Figs. 3 , 8 , 209, 229, 244)

Type Material. Holotype (male): Queensland, 3 km ENE of Mt. Tozer , 12° 44' S, 143° 14' E, 28 June–4 July 1986, T. Weir & A. Calder. Deposited in the ANIC . Paratypes (67): Northern Territory, 5 km SE Mt. Borradaile stn., 12° 3' S, 132° 57' E, 27 May 1999, C. Watts (1 SAMA) ; Darwin , 12° 27' S, 130° 50' E, 13 May 1963, C. Watts (9 SAMA) ; Holmes Jungle , 11 km NE by E of Darwin , 12° 24' S, 130° 56' E, 24 March 1998, C. H. S. Watts (3 SAMA) ; Queensland, 3 km W of Batavia Downs , flight intercept trap, 12° 40' S, 142° 39' E, 22 June–23 August 1992, P. Zborowski & J. Cardale (5 ANIC) ; 40 km N Coen , 13° 41' S, 143° 5' E, 25 July 1982, C. Watts (19 SAMA) ; 7 km S of Batavia Downs , flight intercept trap, 12° 43' S, 142° 42' E, 19 June–22 July 1992, P. Zborowski & E. S. Nielsen (2 ANIC) ; Heathlands , F.I. T., ANIC 1239 closed scrub (=heath), 11° 45' S, 142° 35' E, 26 January–29 February 1992, P. Feehney (9 ANIC) ; same locality, 11° 45' S, 142° 35' E, 1–22 March 1992, P. Feehney (10 ANIC) ; Heathlands , flight intercept trap, 11° 45' S, 142° 35' E, 1 June–25 July 1992, P. Zborowski & E. S. Nielsen (1 ANIC) ; Heathlands , Malaise trap, 11° 45' S, 142° 35' E, 18 August–18 September 1992, P. Zborowski & L. Miller (1 ANIC) ; Peach Creek , 13° 35' S, 143° 4' E, 24 July 1982, C. Watts (1 SAMA) ; Western Australia, 14 km SbyE Kalumburu Mission, CALM Site 4/3 [Western Australian Department of Conservation and Land Management], at light, open forest, 14° 25' S, 126° 40' E, 3–6 June 1988, T. A. Weir (1 ANIC) ; East Kimberley, Meelarie Creek , 5 km N Drysdale Crossing , elev. 350 m, 15° 40' S, 126° 24' E, 19 June 1999, L. Hendrich (2 NMW) ; Mining Camp, Mitchell Plateau , ex. yellow tray, 14° 49' S, 125° 50' E, 9–19 May 1983, I. Naumann, J. Cardale (3 ANIC) .

Differential Diagnosis. Externally very similar to other members of the reticulata Group ( Figs. 1–4 ); reliable determinations will be based on study of the aedeagus. Similar to H. reticulositis in the minute plaques; differing therefrom in the smaller size (ca. 1.25 vs. 1.45 mm), and details of the aedeagus ( Figs. 8 , 9 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.25/0.56; head 0.22/ 0.33; pronotum 0.32/0.44, PA 0.37, PB 0.44; elytra 0.75/0.56. Dorsum dark brown, dull; legs brown; palpi light brown except distal 2/3 of last palpomere darker. Head and pronotum markedly microreticulate, setae short but distinctive.

Frons punctures ca. 1xef; interstices ca. 1xpd. Mentum and postmentum microreticulate. Genae weakly raised, lacking posterior ridge. Pronotal punctures on disc slightly larger than those of frons, interstices ca. 1xpd; PF1 absent; PF2 moderately deep, oblique, separated by about width of a fovea; PF3 shallow, broad; PF4 shallow.

Elytral punctures slightly larger than largest pronotal punctures. Intervals not raised, very effacedly microreticulate, width about 1xpd, interstices between punctures of a row narrower, each puncture with distinctive short seta. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form moderately strong angle with one another.

Plaques nearly absent, minute ovals at posterior of shallow median depression. P1 laminate; median carina angulate in profile. P2 narrow, l/w ca. 3/1, sides parallel, apex blunt. AIS flat, width at arcuate posterior margin 2–3x P2. Protibia (male) straight, with small, sharp tubercle at distal 2/3; mesotibia simple; metatibia parallel-sided or nearly so for most of length, without setal brush. Abdominal apex symmetrical.

Aedeagus ( Fig. 8 ) main-piece with very large pointed process on right side, with a small process issuing from its base (visible in lateral view); left paramere widest subbasally, then tapering to narrow tip, setae very sparse, in a row on ventral margin; right paramere markedly arcuate, setae clustered at tip; gonopore bearing flagellum long. Female last tergite without incisions, with two transverse ridges, setae slender, tapering; gonocoxite and spermatheca as illustrated (Figs. 209, 229).

Etymology. Named in reference to the relationship to H. reticulata .

Distribution. Currently known from the northernmost areas of Western Australia, Northern Territory, and Queensland (Fig. 244).

Figures

FIGURES 1–4. Hydraena, dorsal and lateral habitus of holotypes. —1. H. reticulata. —2. H. mitchellensis. —3. H. reticuloides. —4. H. reticulositis.

FIGURES 5–8. Aedeagi of holotypes. —5. H. reticulata. —6. H. reticulata (after Zwick 1977). —7. H. mitchellensis. —8. H. reticuloides.

FIGURES 9–10. Aedeagi of holotypes. —9. H. reticulositis. —10. H. zwicki.