Hydraena inancala, 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 : 93

Hydraena inancala new species

(Figs. 157, 161, 162, 259)

Type Material. Holotype (male): Queensland, Girraween N. P., Bald Rock Creek at "Under-ground Creek", ex. sand/gravel streambank, 28° 51' S, 151° 57' E, 22 January 1998, P. D. Perkins. Deposited in the QMBA . Paratypes (15): Australian Capital Territory, Wombat Creek , 6 km NE of Piccadilly Circus, flight intercept window/ trough trap, elev. 750 m, 35° 19' S, 148° 51' E, 1–30 March 1985, Weir, Lawrence, Johnson (3 ANIC) ; New South Wales, Kiola Forest Pk., 15 km N Batemans Bay, wet sclerophyll litter, elev. 20 m, 35° 42' S, 150° 11' E, 30 August 1982, S. & J. Peck (SBP 119) (9 ANIC) ; Unnamed creek drains into Crawleys Creek , 36° 56' S, 149° 43' E, 13–22 June 1999, J. & R . Miller (site 731) (1 ANIC) ; Queensland, Girraween N. P., Bald Rock Creek at "Under-ground Creek", ex. sand/gravel streambank, 28° 51' S, 151° 57' E, 22 January 1998, P. D. Perkins (2 MCZ) .

Differential Diagnosis. Externally very similar to H. extorris ; differing therefrom by the slightly coarser punctation, the slightly different plaques, and, in males, the more strongly arcuate protibiae (Figs. 157, 159). The aedeagi of the two species differ markedly (Figs. 161, 164). The terminal part of the aedeagus somewhat resembles that of H. larsoni (Fig. 166), but the main-piece differs markedly therefrom, completely lacking the large sclerotized process that is present in other members of the hamifera group.

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.69/0.68; head 0.26/ 0.40; pronotum 0.39/0.55, PA 0.45, PB 0.48; elytra 1.04/0.68. Head dark brown to piceous; pronotum and elytra dark brown, lateral margins of pronotum lighter than disc; legs brown; palpi light brown to testaceous, tip of last palpomere not darkened.

Frons punctures ca. 1xef; interstices weakly shining, ca. 1xpd. Clypeus microreticulate. Mentum and postmentum dull, microreticulate. Genae weakly raised, lacking posterior ridge. Pronotal punctures on disc 2–3xpd and deeper than those of frons, interstices shining, varying from narrow walls forming reticulate pattern anteriorly and posterior, to 1xpd on disc; PF1 absent; PF2 small, shallow; PF3 moderately deep, broad; PF4 shallow.

Elytral serial punctures very regular, about equal size of largest pronotal punctures; intervals not raised, shining, width ca. 1xpd, as are interstices between punctures of a row; apices in dorsal aspect conjointly rounded, in posterior aspect margins form shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/11/4. P1 laminate; median carina angulate in profile. P2 l/w ca. 5/2, sides parallel or slightly divergent, apex blunt. Plaques located in posterior 3/5 of metaventrite at margin of median triangular depression, plaques straight, very narrowly separated anteriorly, each plaque with lateral margin gradual, medial margin abrupt. AIS flat, width at arcuate posterior margin ca. 2x P2. Profemur (male) with sharp tubercle on medial margin at about basal 1/3. Protibia arcuate, slightly thickened in distal 1/2; mesotibia simple; metatibia slender, medial surface very weakly emarginate over distal 2/3. Last sternite with off-center lobe that fits into counterpart emargination of last tergite.

Aedeagus (Fig. 161, 162) main-piece subtubular, without process on right side; base slightly asymmetrical; distal piece terminally with two processes, gonopore on thin process angled toward left side, other process lobe-shaped and angled toward right side; left paramere much longer than right, angularly produced on ventral surface, setae in one group, more-or-less in a line; right paramere short, simple, setae in two groups. Female last tergite with three incisions, delimiting four lobes, setae slender, tapering.

Etymology. "No bent arm"; named in reference to the lack of an arm-shaped process on the aedeagus, such as is present in H. hamifera .

Distribution. Currently known from southern New South Wales, Australian Capital Territory, and one disjunct locality in southern Queensland (Fig. 259).

Remarks. There is variation in the shape of the distal piece of the aedeagus. A variant from Wombat Creek, ACT is illustrated (Fig. 162); this variant is drawn at a slightly different orientation than the drawing of the holotype (Fig. 161), illustrating how some variants will seem more markedly different if viewed at a slightly different angle than the compared specimen.