Hydraena reticulositis, 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 : 15-16

Hydraena reticulositis new species

( Figs. 4 , 9 , 246)

Type Material. Holotype (male): Western Australia, Mining Camp, Mitchell Plateau , ex. yellow tray, 14° 49' S, 125° 50' E, 9–19 May 1983, I. Naumann, J. Cardale. Deposited in the ANIC . Paratypes (10): Northern Territory, Border Waterhole , Musselbrook Ck. 15 km W by S of Musselbrook Mining Camp ( QLD) , large permanent pool in gorge, muddy edges, rocky, algal growth, 18° 37' S, 137° 59' E, 14 May 1995, T. Weir (1 ANIC) ; Katherine Gorge N. P., Butterfly Gorge , 13° 44' S, 131° 34' E, 5 December 1980, M. B. Malipatil (1 MAGD) ; Queensland, “ Amphitheatre Springs ”, 28 km N by E of Musselbrook Mining Camp, small, spring fed pools, dark water, roots and debris in water, algal growth, scum on surface, 18° 21' S, 138° 11' E, 12 May 1995, T. Weir (1 ANIC) ; Western Australia, Mining Camp, Mitchell Plateau , ex. yellow tray, 14° 49' S, 125° 50' E, 9–19 May 1983, I. Naumann, J. Cardale (2 ANIC) ; Synnot Range , 16° 25' S, 125° 28' E, 1 September 1969, D. D. Giuliani (5 WAMP) .

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. reticuloides in the minute plaques; differing therefrom in the larger size (ca. 1.45 vs. 1.25 mm), and details of the aedeagus ( Figs. 8 , 9 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.45/0.63; head 0.25/ 0.37; pronotum 0.38/0.50, PA 0.40, PB 0.44; elytra 0.84/0.63. 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 deep, oblique, separated by less than width of a fovea; PF3 moderately deep, broad; PF4 moderately deep, broad.

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) at distal 2/3 slightly widened, with small, sharp tubercle; mesotibia simple; metatibia extremely weakly arcuate, nearly straight, without setal brush. Abdominal apex symmetrical.

Aedeagus ( Fig. 9 ) main-piece with small, truncate tipped process on right side, with a long cylindrical process issuing vertically from its base (visible in lateral view); left paramere angled at midlength, widened apically, setae sparse, in a row on ventral margin; right paramere widened at midlength and at apex, setae on enlarged apical part; gonopore bearing flagellum vertical. Female last tergite without incisions, with two transverse ridges, setae slender, tapering.

Etymology. Named in reference to the reticulate dorsum and the arid region this species inhabits.

Distribution. Currently known from the northern areas of Western Australia and Northern Territory, and northwestern Queensland (Fig. 246).

Figures

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

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

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