Hydraena spinissima, 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 : 35-36

Hydraena spinissima new species

( Figs. 45 , 52 , 250)

Type Material. Holotype (male): Queensland, Main Range N. P., Cunningham's Gap, Gap Creek , ex. bare rocks in splash zone, elev. 700 m, 28° 3' S, 152° 24' E, 21 January 1998, P. D. Perkins. Deposited in the QMBA . Paratypes (3): New South Wales, 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) ; Queensland, 90 km SW Brisbane , 40 km NE Warwick, 28° 3' S, 152° 22' E, 26 August 2004, M. A. Jäch (AU 17) (1 NMW) ; Lamington, Binna Burra, Comera River , stones, 28° 15' S, 153° 6' E, 17 November 1982, Endrödy-Younga (AU 73) (1 TMSA) .

Differential Diagnosis. Similar to H. luminicollis and H. antaria in body size, and dorsal punctation ( Figs. 45, 47, 48 ); differing from both by the posteriorly positioned, distinct pronotal macula, the slightly more cordiform pronotum, and the less convex elytra; additionally differing from both species by the nonmodified metatibiae of males. The aedeagus of H. spinissima differs greatly from that of the compared species ( Figs. 52 , 53, 55 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.62/0.66; head 0.26/ 0.36; pronotum 0.39/0.48, PA 0.41, PB 0.43; elytra 0.97/0.66. Head dark brown; pronotum with dark brown macula surrounded by light brown; elytra dark brown; legs and palpi light brown to testaceous, tip of palpi not darker.

Frons punctures ca. 1xef; interstices shining, 1–2xpd. Clypeus microreticulate laterally, finely sparsely punctate medially. Mentum shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotal punctures on disc ca. 2xpd those of frons, interstices shining, anteriorly and posteriorly 0.5–1xpd, on disc 1–3xpd; PF1 absent; PF2 very shallow; PF3 and PF4 shallow, confluent.

Elytral punctures on disc slightly smaller than 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 very weak angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/2/9/6. P1 laminate; median carina angulate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt. Plaques parallel or nearly so, slightly raised, located in posterior 1/2 of metaventrite on sides of deep median depression. AIS flat, width at arcuate posterior margin 2x P2. Protibia (male) gradually widened to about distal 1/3, then markedly excavate, a prominent spine at base of excavation; mesotibiae and metatibia slender. Last tergite with very slightly asymmetrical concavity.

Aedeagus ( Fig. 52 ) main-piece with large, markedly angulate process on right side; distal piece with many spine-like processes; left paramere longer than right, very asymmetrical, apex tapering and ending in several spines, setae few in number, in a subapical and a dorsal group; right paramere short, apically widened, with about seven long setae. Females not yet known.

Etymology. Named in reference to the many spine-like processes of the aedeagus.

Distribution. Currently known from the southeastern corner of Queensland, and northern New South Wales (Fig. 250).

Figures

FIGURES 45–48. Hydraena, aedeagi of holotypes. —45. H. spinissima. —46. H. dorrigoensis. —47. H. antaria. —48. H. luminicollis.

FIGURES 49–52. Hydraena, aedeagi of holotypes. —49. H. tricantha. —50. H. dorrigoensis. —51. H. tricantha (after Zwick 1977). —52. H. spinissima.

FIGURES 53–56. Hydraena, aedeagi of holotypes. —53. H. antaria. —54. H. hynesi. —55. H. luminicollis. —56. H. hynesi (after Zwick 1977).