Hydraena bidefensa, 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 : 44-45

Hydraena bidefensa new species

(Figs. 66, 70, 258)

Type Material. Holotype (male): New South Wales, Bruxner Flora Reserve , ex. leaf/twig debris in streambed pools, 30° 15' S, 153° 6' E, 28 January 1998, P. D. Perkins. Deposited in the QMBA . Paratypes (60): New South Wales, Same data as holotype (1 MCZ); Cabbage Tree Creek, Canberra / Coast Road, gravel and sand at edge of small densely shaded stream in sclerophyll forest, elev. 85 m, 35° 34' S, 150° 2' E, 22 July 2000, N. Porch (93) (2 ANIC); Dorrigo N. P., Rosewood Creek, upstream from Coachwood Falls, ex. gravel/ sand stream bank, elev. 650 m, 30° 22' S, 152° 40' E, 26 January 1998, P. D. Perkins (1 MCZ); Dorrigo N. P., Sassafras Creek , upstream from Casuarina Falls , silty gravel bank in shade, elev. 650 m, 30° 22' S, 152° 40' E, 27 January 1998, P. D. Perkins (6 MCZ); Dorrigo N. P., south slope Dome Mt. , subtropical rainforest, wet leaves and flood debris, forest stream, FMHD #86-682 , elev. 720 m, 30° 21' S, 152° 46' E, 28 December 1986, A. Newton & M. Thayer (778) (8 FMNH); Dorrigo N. P., East end Blackbutt Track, window trap, subtrop. rainf., elev. 710 m, 30° 20' S, 152° 24' E, 28 February to 5 March 1980, A. Newton & M. Thayer, (1 USNM); Headwaters of Nullica River , headwater stream, 37° 4' S, 149° 47' E, 24 June 1997, J. & R . Miller (site 659) (5 ANIC); same locality, 37° 4' S, 149° 47' E, 10 June 1999, J. & R . Miller (site 659) (1 ANIC); Ingalla S. F., 13 km S Macksville, flight intercept trap, sclerophyll forest (wet), elev. 40 m, 30° 41' S, 152° 56' E, 12 June–26 August 1982, S. & J. Peck (1 ANIC); Macquarie Pass Nt. Pk. , drift debris along stream, FMHD #83-273 , 34° 34' S, 150° 40' E, 17 July 1983, L. E. Watrous (2 FMNH); Mt. Glennie, 16 km E Woodenbong, rainforest, flight intercept trap, elev. 910 m, 28° 22' S, 152° 28' E, 25 November 1982 – 3 February 1983, [collector not given] (1 QMBA); Twin Falls, 14 km SE Mossvale , Berlesate ANIC 852 , moss, grass, litter, elev. 600 m, 34° 38' S, 150° 29' E, 11 July 1982, L. Hill (7 ANIC); Unnamed creek drains into Crawleys Creek , 36° 56' S, 149° 43' E, 13–22 June 1999, J. & R . Miller (site 731) (12 ANIC); Unnamed creek drains into Nungatta Creek , 36° 7' S, 149° 29' E, 21 February 1998, J. & R . Miller (site 566a) (1 ANIC); same locality, 23 February 1998, J. & R . Miller (site 566c) (1 ANIC); same locality, 12 February 2000, J. & R . Miller (site 566c) (2 ANIC); same locality, 12 February 2000, J. & R . Miller (site 566b) (4 ANIC); same locality, 13 February 2000, J. & R . Miller (site 566d) (2 ANIC) ; Queensland, Tambourine Mt. , 27° 53' S, 153° 11' E, 1 January–30 December 1970, H. Franz (1 NMW) ; Victoria, Croajingolong N. P., South-West Arm Rd. , 11 km NW Mallacoota, Banksia woodland, ex window trap, FMHD #93-74 , elev. 20 m, 37° 31' S, 149° 41' E, 10–23 February 1993, A. Newton & M. Thayer (1 ANIC) .

Differential Diagnosis. Similar to H. cultrata in color pattern, the pronotum usually uniformly testaceous, contrasting with the dark brown head and elytra (Figs. 66, 173); differing therefrom by the larger size (ca. 1.50 vs. 1.25 mm), the slightly less transverse pronotum (w/l ca. 1. 24 vs. 1.31), the slightly more shining dorsum, and the straight plaques. The aedeagi of the two species distinctively differ (Figs. 69, 70).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.47/0.58; head 0.22/ 0.33; pronotum 0.37/0.46, PA 0.38, PB 0.39; elytra 0.87/0.58. Head dark brown, lateral areas of clypeus lighter; pronotum, labrum, maxillary palpi and legs testaceous; elytra brown.

Frons punctures slightly less than 1xef; interstices shining, 2–5xpd. Clypeus microreticulate. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotal punctures on disc slightly larger than those of frons, ca. 1xef; each puncture with very fine, rather long, recumbent seta; interstices shining, on disc 2–4xpd, anteriorly and posteriorly 1–3xpd; PF1 and PF4 absent; PF2 very shallow, almost absent; PF3 shallow, broad.

Elytral punctures slightly smaller than largest pronotal punctures. Intervals not raised, shining, width ca. 2–3xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointy rounded to subtruncate, in posterior aspect margins form strong angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 4/1/10/8. P1 laminate; median carina weakly angulate in profile. P2 moderately narrow, l/w ca. 2/1, sides parallel, apex blunt. Plaques very narrow, carinate, parallel, located on sides of deep median depression; a small "accessory plaque" on each side of anterior angle of median depression, narrowly separated from carinate plaques. AIS flat, width at arcuate posterior margin 2x P2. Profemur with tiny acute tubercle on medial margin at about basal 1/3. Protibia thick, gradually widened from base to about distal 2/3, then excavate on medial margin; mesotibia simple. Metatibia slender, inner margin (microslide mount) with few, widely spaced, long, very fine hair-like setae over basal 1/2, apical 1/2 with widely spaced, short, stout spines. Last sternite very slightly asymmetrical, produced in small rounded point; last tergite with off-center, deep concavity.

Aedeagus (Fig. 70) main-piece with large lobe on right side, bisinuate, pointed at apex, contours on side adjacent to right paramere the same as paramere contours; distal piece with thin apical lobe that extends beyond gonopore bearing flagellum; left paramere shorter and wider than right, setae in two groups; right paramere slender, nearly straight, setae in one group at weakly widened apex. Female last tergite with apicomedian incision delimiting two lobes, setae slender, tapering.

Etymology. Named in reference to the right paramere and the adjacent, similarly contoured process of the aedeagus.

Distribution. Currently known from Victoria, New South Wales, and southeasternmost Queensland. (Fig. 258).

Remarks. The color of the pronotum varies from clear testaceous, without a hint of a macula, to testaceous or light brown laterally, with a brown, diffusely margined macula. In some males the "accessory plaques" are smaller than in the holotype, and sometimes one of them will be confluent with the carinate 'regular' plaques. In females studied the plaques are not carinate, although they are distinctly raised posteriorly; also, the area of the "accessory plaques" is joined to the regular plaques, forming a shiny, but sparsely punctate, angle that joins the regular plaques. There is also some variation in the details of the male genitalia; for example, the aedeagus of the single male from Macquarie Pass National Park has slightly different raised portions near the middle of the ventral surface; otherwise the aedeagus is like that of the holotype.