Hydraena barbipes Zwick, 1977

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 : 53-54

Hydraena barbipes Zwick, 1977

(Figs. 85, 89, 90, 240)

Hydraena barbipes Zwick, 1977: 158 .

Type Material. Holotype (male): Western Australia, Millstream [ca. 21° 35' S, 117° 4' E] [labels: (21.35S 117.04E) Millstream, WA., 2.xi.70 from gravel at edge of pool at pipe crossing. E. Britton // [pink label] // Holotype // Aedeagus drawn by P. D. Perkins // DIGITAL IMAGE captured 2004 P. D. Perkins // Hydraena barbipes Zwick Holo-Typus des. P. Zwick 1977]. Deposited in the ANIC.

Differential Diagnosis. Recognized by the combination of the large body size (ca. 1.95 mm), the shape and relative size of the pronotum, the large and well impressed pronotal foveae PF2, the large plaques, which are posteriorly carinate in males, and the unique shape of the male metatibiae (Fig. 85). The metatibiae of males are widened on the inner surface near midlength and bear a large and dense brush of setae. Differentiated from H. luridipennis , H. simplipes , and H. impercepta by the large, well delimited plaques (among other characters). Differentiated from H. pilipes and H. robusta by the narrower and differently shaped pronotum, the presence of deep pronotal foveae PF2, and form of the male metatibiae. The aedeagus of H. barbipes (Figs. 89, 90) is very distinct from those of the compared species.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.93/0.84; head 0.32/ 0.44; pronotum 0.48/0.58, PA 0.50, PB 0.56; elytra 1.19/0.84. Dorsum dark brown, legs and palpi brown, distal 1/3 of last palpomere darker.

Frons microreticulate, effacedly so on disc, punctures ca. 1.5xef; interstices ca. 1xpd. Clypeus microreticulate or micropunctulate. Mentum weakly shining, very finely sparsely punctate; postmentum microreticulate. Genae raised, lacking posterior ridge. Pronotum densely coarsely punctate, punctures on disc deep, ca. 1.5–2xpd those of frons, interstices varying from narrow walls to ca. 1xpd; PF1 absent; PF2 deep, oblique oval, separated by slightly less than width of a fovea; PF3 and PF4 very shallow, broad.

Elytral punctures slightly smaller than largest pronotal punctures. Intervals not raised, shining, width ca. 1.5xpd. Interstices between serial punctures 1xpd or slightly larger. Apices (male) in dorsal aspect separately, broadly rounded, in posterior aspect margins forming marked angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/2/2. P1 laminate; median carina slightly angulate in profile. P2 moderately wide, l/w ca. 2/1, sides parallel, apex blunt. Plaques large, located in posterior 7/10 of metaventrite on sides of deep median triangular depression, plaques roundly raised, becoming carinate at posterior extreme. No midlongitudinal carina between mesoventral intercoxal process and plaques. AIS flat, width at arcuate posterior margin ca. 2x P2. Protibia straight, gradually increasing in width apically. Metatibia weakly arcuate on lateral surface, medial surface strongly widened at midlength, with large brush of hairs from widest part to nearly apical end. Abdominal apex simple.

Aedeagus (Figs. 89, 90) main-piece short and wide, without lobe near base, with large fingerlike, strongly sclerotized lobe on apical part, on right side of ventral surface; left paramere slightly widened in distal 1/3, with two groups of setae; right paramere triangular in proximal 2/3, becoming very narrow in distal 1/3, with two groups of setae. Female last tergite with apicomedian incision delimiting two lobes, setae slender, tapering.

Distribution. Currently known from western Western Australia (Fig. 240).

Remarks. The metaventral depression of females is slightly shallower and less triangular than that of males, and the plaques do not become carinate posteriorly.

Material Examined (191): Western Australia, 1 km N Red Hill Station , 21° 58' S, 116° 4' E, 22 May 2001, C. H. S. Watts (6 SAMA) ; 1 km NNE Millstream , 21° 35' S, 117° 4' E, 3–4 April 1971, M. S. Upton (3 ANIC) ; 10 km NW Eerala Station , 21° 19' S, 117° 2' E, 23 May 2001, C. H. S. Watts (1 SAMA) ; 2 km W Carey Downs , 25° 37' S, 115° 26' E, 19 May 2001, C. H. S. Watts (1 SAMA) ; 5 km SE of Millstream homestead, 21° 37' S, 117° 6' E, 17 April 1971, Upton & Mitchell (17 ANIC) ; Cadjeput Rockhole E of Woodstock Station , at UV florescent light at night 6:00 to 8:45 PM, 21° 32' S, 119° 9' E, 29 September 1988, B. P. Hanich et. al. (BPH 29-11) (2 WAMP) ; Cane River , Cane River Hs. (old), 22° 5' S, 115° 37' E, 22 May 2001, C. H. S. Watts (6 SAMA) ; Cane River, Hwy 1 crossing, 21° 58' S, 115° 35' E, 22 May 2001, C. H. S. Watts (2 SAMA) ; Fortescue River 12 km S Newman , 23° 28' S, 119° 44' E, 27 May 2001, C. H. S. Watts (4 SAMA) ; Gascoyne River, Gascoyne Junction , 25° 3' S, 115° 12' E, 21 May 2001, C. H. S. Watts (7 SAMA) ; Lyndon River Bridge, 23° 36' S, 113° 51' E, 13 August 1975, K. & E. Carnaby (1 ANIC) ; Millstream, creek near Deep Reach , 21° 35' S, 117° 4' E, 8 November 1970, E. B. Britton (3 ANIC) ; Millstream, Crossing pool, 21° 35' S, 117° 4' E, 24 May 2001, C. H. S. Watts (4 SAMA) ; Millstream, Crystal Pool , at light, 21° 35' S, 117° 4' E, 5 November 1970, E. B. Britton (4 ANIC) ; Millstream , gravel at water’s edge in pipe crossing pool, 21° 35' S, 117° 4' E, 2 November 1970, E. Britton (9 ANIC) ; Millstream , shallow stream, from gravel at edge of pool at pipe crossing, 21° 35' S, 117° 4' E, 2 November 1970, E. Britton (1 ANIC) ; Woodstock Station , at UV florescent light at night 6:00 to 7:30 PM, 21° 37' S, 119° 1' E, 24 September 1988, B. P. Hanich (site WS 9) (105 WAMP) ; Woodstock Station , Hill #3 , N of Gallery Hill , at UV florescent light at night, 5:55 to 7:30 PM, 21° 39' S, 119° 2' E, 25 September 1988, B. P. Hanich (BPH 25-6) (6 WAMP) ; Wooramel River, Callytharra Springs Station , 25° 49' S, 115° 22' E, 20 May 2001, C. H. S. Watts (7 SAMA) ; same locality, 25° 49' S, 115° 22' E, 26 May 2001, C. H. S. Watts (2 SAMA) .