Hydraena parciplumea, 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 : 75-76

Hydraena parciplumea new species

(Figs. 114, 117, 260)

Type Material. Holotype (male): Northern Territory, McArthur River , 80 km SW of Borroloola, 16° 39' S, 135° 51' E, 13 May 1973, M. S. Upton. Deposited in the ANIC.

Differential Diagnosis. Similar in dorsal habitus to H. australica ; differing therefrom by the smaller size (ca. 1.31 vs. 1.45 mm), the lighter borders surrounding the pronotal macula, the slightly more distinctive dorsal setae, and the narrow, carinate plaques (Figs. 115, 117). The aedeagi of the two species distinctively differ (Figs. 114, 119, 120).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.31/0.56; head 0.21/ 0.33; pronotum 0.34/0.45, PA 0.37, PB 0.43; elytra 0.77/0.56. Head dark brown to piceous; pronotum light brown to testaceous, with large rectangular brown macula; elytra dark brown; legs and palpi light brown to testaceous.

Frons punctures ca. 1xef; interstices shining, ca. 1xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum and postmentum weakly shining, weakly microreticulate. Genae very weakly raised, lacking posterior ridge. Pronotal punctures on disc fine and sparse, interstices shining, 3–4xpd, punctures larger and denser anteriorly and posteriorly ca. 1–2xpd those of frons, interstices ca. 1xpd; each pronotal puncture with very fine, moderately long seta that lies flat on cuticle in dry specimens; PF1 and PF4 absent; PF2 very shallow, almost absent; PF3 shallow, broad.

Elytral punctures near base ca. 1xpd of largest pronotal punctures, becoming finer posteriorly. Intervals not raised, shining, width about 2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins form moderate angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/1/5/4. Plaques narrow, carinate, weakly arcuate, on sides of deep depression. P1 laminate; median carina angulate in profile. P1 laminate; median carina angulate in profile. P2 moderately wide, l/w ca. 4/3, sides parallel, apex blunt. AIS flat, width at arcuate posterior margin almost 2x P2. Legs simple. Last sternite weakly produced apicomedially; last tergite deeply notched apicomedially.

Aedeagus (Fig. 114) main-piece with very narrow, short, sinuate, pointed process on right side; distal piece bilobed in ventral view, multi-lobed in lateral view, with cluster of curving, long setae on dorsal surface, gonopore-bearing flagellum very short; left paramere inserting closer to base than insertion of right paramere; left paramere markedly sinuate in lateral view, much longer than right, distal 1/2 slightly widened and with two groups of very long setae; right paramere partially hidden in ventral view, markedly arcuate in lateral view, with about ten long setae on ventral margin near base, setae wrapping around ventral surface of mainpiece. Females not yet known.

Etymology. Named in reference to the sparse, fine setae on the dorsum, and the very long, sparse paramere setae.

Distribution. Currently known only from the type locality in northwestern Queensland (Fig. 260).