Hydraena uniforma, Perkins, 2014

PERKINS, PHILIP D., 2014, A revision of the water beetle genus Hydraena Kugelann for southern Africa (Coleoptera: Hydraenidae), Zootaxa 3758 (1), pp. 1-92 : 29-30

Hydraena uniforma , new species

Figs. 18 (habitus), 20 (aedeagus), 85 (map)

Type material. Holotype (male): Namibia: Brandberg , Wasserfallflache, yellow pan traps 8, elev. 2000 m, 21° 10' S, 14° 32' E, 19–21 x 1998, R. Butlin & J. Altringham ( SMW) . Paratypes (233): Angola: Vana e Lombe, near Tampa, pools in dry river bed; rock and coarse sand, elev. 1372 m, 15° 30' S, 13° 30' E, 14 vi 1954, J. Balfour- Browne (269) (21 BMNH) ; Namibia: Brandberg , Wasserfallflache, yellow pan traps 8, elev. 2000 m, 21° 10' S, 14° 32' E, 19–21 x 1998, R. Butlin & J. Altringham (2 SMW) ; C. Namib desert, Weissenborn farm, shore washing, 26° 3' S, 16° 24' E, 9 viii 1989, Endrödy-Younga & Klimaszewski (#2643) (1 TMSA) ; Koriankab Waterhole , 10 mi. WNW Windhoek, Bare sand and gravel shores, elev. 1676 m, 22° 30' S, 16° 56' E, 19 v 1954, J. Balfour- Browne (212) (1 BMNH) ; Naukluft cascades, cascades, 24° 16' S, 16° 15' E, 12 viii 1989, Endrödy-Younga & Klimaszewski (#2648) (2 TMSA) ; Naukluft , Felseneck farm, shore washing, 24° 12' S, 16° 4' E, 24 x 1974, Endrödy-Younga (#414) (1 TMSA) ; Naukluft , Felseneck farm, water collection, 24° 12' S, 16° 4' E, 24 x 1974, Endrödy-Younga (#415) (6 TMSA) ; Naukluft , Naukluft Park, shore washing, 24° 16' S, 16° 15' E, 26 x 1974, Endrödy-Younga (#431) (33 TMSA) ; Naukluft , Naukluft Park, water collection, 24° 16' S, 16° 15' E, 22 i 1975, Endrödy-Younga (#563) (5 TMSA) ; Naukluft River , shore washing, 24° 16' S, 16° 15' E, 10 viii 1989, Endrödy- Younga & Klimaszewski (#2644) (1 TMSA) ; Okahandja , small shaded pool in rock-hole, 21° 59' S, 16° 52' E, 21 v 1954, J. Balfour-Browne (1 BMNH) ; Windhoek , Eros Mt., shore washing, elev. 1600 m, 22° 34' S, 17° 6' E, 10 ix 1974, Endrödy-Younga (#367) (2 TMSA) ; Windhoek , In pools in rocky bed of stream, elev. 1654 m, 22° 34' S, 17° 5' E, 16 v 1954, J. Balfour-Browne (203) (157 BMNH) .

Differential diagnosis. Recognized by the non-serial elytral punctation, which is quite similar in size and density to the pronotal punctation, giving a very uniform appearance. The aedeagus shows some similarity to that of H. elephanta ( Figs. 20, 21 ), but that species has serial elytral punctures, and the dorsal habitus of the two species differ distinctively ( Figs. 18 , 19 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.68; head 0.25/0.39; pronotum 0.40/0.49, PA 0.40, PB 0.46; elytra 1.02/0.68. Dorsum of head dark brown to piceous; pronotum dark brown with lighter anterior angles; elytra dark brown; legs brown; maxillary palpi brown (holotype slightly teneral).

Frons punctures ca. 1xef, larger and denser near eyes than medially; interstices very weakly shining, 0.5–1xpd laterally, 1–2xpd medially. Clypeus mcr laterally, very finely sparsely punctulate medially. Mentum moderately densely finely punctate, interstices weakly shining; postmentum densely micropunctulate, dull. Genae raised, shining, without posterior ridge.

Pronotum laterally emarginate behind middle; anterior margin straight behind eyes, very slightly, if at all, emarginate behind frons, scintilla absent; punctures on disc slightly larger and denser than those of frons, interstices weakly shining, 0.5–2xpd, punctures larger and slightly denser at anterior and posterior; PF1 absent; PF2 moderately deep; PF3 deep; PF4 shallow.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. posterior 1/3; lateral explanate margin moderately wide; punctures random, not serial, on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Interstices very weakly shining, on basal 1/3 ca. 1–2xpd. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 3/1.5/7/6. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides parallel or slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight, parallel, weakly raised, subcarinate, margins not strongly demarcated, located at sides of moderately deep median depression. Metaventrite without midlongitudinal carina between intercoxal process and median depression. AIS width at slightly arcuate posterior margin ca. 1.5x P2. All tibiae slender, pro- and metatibiae very slightly arcuate, mesotibiae straight. Abdominal apex symmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1): last tergite moderately broadly rounded, without apicomedian notch, ca. 24 non-hooked, nearly contiguous setae, median gap narrow, each seta moderately wide; gonocoxite not midlongitudinally divided, apical margin moderately broadly rounded, low transverse ridge evident at border of microreticulation; spermatheca simple, type C shape.

Etymology. Named in reference to the uniformly random (non-serial) dorsal punctation.

Distribution. Currently known from several localities in central Namibia, and one locality in southern Angola ( Fig. 85 ).

Figures

FIGURE 18. Hydraena uniforma, holotype, dorsal and lateral habitus.

FIGURE 19. Hydraena elephanta, holotype, dorsal and lateral habitus.

FIGURES 20–21. Aedeagi of holotypes.

FIGURES 85–88. Geographical distributions of Hydraena species.