Hydraena deliquesca, 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 : 111-112

Hydraena deliquesca new species

(Figs. 180, 185, 247)

Type Material. Holotype (male): Queensland, Wallaman Falls , 5 km E, 18° 58' S, 146° 14' E, 6 November 1995, C. Watts. Deposited in the SAMA . Paratypes (141): New South Wales, Gilgandra , 31° 42' S, 148° 40' E, 19 November 1992, C. Watts (1 SAMA) ; Queensland, 20 miles N. of Cairns, Cascade Creek , pot-hole pool in rock, 16° 44' S, 145° 39' E, 11 June 1954, M Laird (4 BMNH) ; 30 km NE Brisbane, Mt. Nebo Road, Pond, ca. 200 m, Sclerophyll forest , elev. 540 m, 27° 24' S, 152° 48' E, 21 August 2004, M. A. Jäch (AU 1) (3 NMW) ; 40 km SSE Brisbane, Mt. Tambourine N. P., Cedar Creek , 27° 55' S, 153° 11' E, 22 August 2004, M. A. Jäch (AU 4) (5 NMW) ; Cathu State Forest, Jaxut, Kangaroo Creek , 20° 49' S, 148° 33' E, 17 March 1997, P. Zwick (54 PZC) ; Eungella N. P., Broken River Track , elev. 720 m, 21° 11' S, 148° 31' E, 13 November 1996, L. Hendrich (23) (1 NMW) ; Lamington National Park, Elabana Falls , ex. rockpool, 28° 15' S, 153° 9' E, 31 December 1997, P. D. Perkins (1 MCZ) ; Mount Spec National Park, falls of Little Crystal Creek at Paluma Road , 18° 58' S, 146° 17' E, 21 March 1992, H. & P. Zwick (1 PZC) ; Mt. Bartle Frere, Josephine Falls , 17° 26' S, 145° 51' E, 6 April 1997, H. & P. Zwick (1 NMW) ; Mt. Lewis Rd. , edge of rainforest, malaise trap, elev. 1000 m, 16° 37' S, 145° 21' E, 17–24 February 1984, L. Masner (1 CMNO) ; SW of Tully, pools below Murray Falls , 18° 9' S, 145° 49' E, 23 March 1992, H. & P. Zwick (23 PZC) ; Townsville , 20 km S, 19° 21' S, 146° 55' E, 6 November 1995, C. Watts (1 SAMA) ; Wallaman Falls , 5 km E, 18° 58' S, 146° 14' E, 6 November 1995, C. Watts (45 SAMA) .

Differential Diagnosis. Differentiated from other large (size ca. 2.05 mm), coarsely punctate species, by the large, smooth and shining interstices on the pronotal disc, the large, narrowly separated plaques, the coarsely punctate elytra with serial punctures not striate-impressed, and the wide explanate elytral margin (Fig. 180). Males have the protibiae weakly bent, and the metatibiae are slender and do not have brushes. The aedeagus is quite distinct (Fig. 185).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 2.03/0.88; head 0.31/ 0.47; pronotum 0.50/0.65, PA 0.54, PB 0.59; elytra 1.24/0.88. Dorsum dark brown, head darker brown or piceous, margins of pronotum slightly lighter, legs brown, tips of femur darker, palpi light brown, tip not darker.

Frons finely punctate, punctures ca. 1xef; interstices ca. 1xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotum anteriorly and posteriorly densely coarsely punctate, interstices narrow walls forming reticulate pattern; punctures distinctly sparser on portions of disc, interstices ca. 2–5xpd; punctures much larger than, ca. 5–7xpd, those of frons; PF1 absent; PF2 shallow; PF3 and PF4 moderately deep, broad.

Elytral punctures largest near base, about equal size of largest pronotal punctures, becoming smaller posteriorly. Intervals not raised, shining, width on disc ca. 2xpd, as are interstices between punctures of a row. Explanate margin wide. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming marked angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/5/0.6. P1 laminate; median carina angulate in profile. P2 moderately wide, l/w ca. 3/2, sides parallel or slightly diverging toward blunt apex. Plaques large, located in posterior 7/10 of metaventrite on sides of median depression, plaques wider posteriorly than anteriorly, separated by less than plaque width. No midlongitudinal carina between mesoventral intercoxal process and plaques. Cuticle non-asperite under hydrofuge pubescence. AIS flat, width at arcuate posterior margin 1.5x P2. Protibia (male) weakly arcuate; mesotibia simple; metatibia very slender, very weakly sinuate, without setal brushes. Abdominal apex asymmetrical.

Aedeagus (Fig. 185) main-piece with large, strongly sclerotized process on ventral surface, near base; apical part of main-piece extended in thin, shield-like, arcuate piece that covers part of ventral face; left paramere wide, tapering at distal end, with three groups of setae; right paramere bifid, with three groups of setae. Female last tergite subrectangular, with three incisions, delimiting four lobes, setae slender, tapering.

Etymology. Named in reference to the pronotal sculpture: the interstices are generally very smooth, and in places the punctures seem to disappear in places, as if by melting.

Distribution. Currently known from eastern Queensland and one interior locality in New South Wales (Fig. 247).