Hydraena namibiensis, 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 : 19-22

Hydraena namibiensis , new species

Figs. 10 (habitus), 12 (aedeagus), 70 (map)

Type material. Holotype (male): Namibia: C. Namib desert, Numis Wasser , shore washing, 26° 3' S, 16° 15' E, 9 viii 1989, Endrödy-Younga & Klimaszewski (#2642) ( TMSA) . Paratypes (1233): Angola: Altoplano: Ongueria , in stagnant pools below waterfall, elev. 1615 m, 15° 19' S, 13° 32' E, 10 vi 1954, J. Balfour-Browne (255) (4 BMNH) ; Altoplano: Ongueria , side pools above waterfall, elev. 1615 m, 15° 19' S, 13° 32' E, 12 vi 1954, J. Balfour-Browne (263) (42 BMNH) ; Humpata, Altoplano , clear rapid stream, rocks & sandy bays, elev. 1828.8 m, 15° 19' S, 13° 28' E, 7-9 vi 1954, J. Balfour-Browne (248) (1 BMNH) ; Ongueria , in fine sand at side of stream above cataracts, elev. 1615 m, 15° 19' S, 13° 32' E, 13 vi 1954, J. Balfour-Browne (7 BMNH) ; Namibia: Aub , 20 mi. S of Windhoek, spring and pools in sand river bed, elev. 1905 m, 22° 56' S, 17° 12' E, 18 v 1954, J. Balfour- Browne (209) (48 BMNH) ; C. Namib desert, Numis Wasser , shore washing, 26° 3' S, 16° 15' E, 9 viii 1989, Endrödy-Younga & Klimaszewski (#2642) (1 TMSA) ; Damaraland, groot Barmen , shore washing, 22° 5' S, 16° 40' E, 12 ix 1975, Endrödy-Younga (#370) (15 TMSA) ; Damaraland, Okahandja , shore washing, 21° 59' S, 16° 52' E, 12 ix 1974, Endrödy-Younga (#369) (40 TMSA) ; Hardap GR: Water Institute : pool shore waterplant treating water catcher, 24° 29.41' S, 17° 51' E, 1 xii 1997, M. Uhlig (2 ZMHB) ; Kaokoveld, Kunene River, Swartbooisdrift , shore washing, 17° 19' S, 13° 49' E, 10 ii 1975, Endrödy-Younga (#645) (11 TMSA) ; Khomashochl., Farm Wissenfels , shore washing, 23° 20' S, 16° 25' E, 14 ix 1974, Endrödy-Younga (#371) (14 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) (128 BMNH) ; Maltah. D., Farm Kamkas 20, shore washing, 24° 36' S, 16° 37' E, 28 x 1974, Endrödy-Younga (#435)(115 TMSA) ; Mukurob 14, Namaland, SE 2518 Ac , 25° 28' S, 18° 7' E, 12–14 iv 1974, none given on label (1 SMW) ; Namib, Gobabeb , shore washing, 23° 34' S, 15° 3' E, 7 ix 1974, Endrödy-Younga (#363)(77 TMSA) ; same locality, 23° 34' S, 15° 3' E, 24 ix 1974, Endrödy-Younga (#377) (14 TMSA) ; same locality, 23° 34' S, 15° 3' E, 24 ix 1974, Endrödy-Younga (#376) (39 TMSA) ; Namib-Naukluft Park, Waterkloof spring, spring, 24° 16' S, 16° 14' E, 29 xi 1997, Kirk-Spriggs & Marais (1 SMW) ; Namib, Sessriem Canyon , shore washing, 24° 35' S, 15° 47' E, 15 i 1975, Endrödy-Younga (#548) (30 TMSA) ; same locality, 24° 35' S, 15° 47' E, 15 i 1975, Endrödy-Younga (#549) (33 TMSA) ; Namib-Naukluft NP, Waterkloof, algae + Carex + Phragmites , shore washing, 24° 16.8' S, 16° 14.2' E, 29 xi 1997, M. Uhlig & E. Marais (1 ZMHB) ; Naukluft, Felseneck farm, shore washing, 24° 12' S, 16° 4' E, 24 x 1974, Endrödy-Younga (#414) (20 TMSA) ; Naukluft, Naukluft Park , shore washing, 24° 16' S, 16° 15' E, 26 x 1974, Endrödy-Younga (#431) (28 TMSA) ; Naukluft River , shore washing, 24° 16' S, 16° 15' E, 10 viii 1989, Endrödy-Younga & Klimaszewski (#2644) (68 TMSA) ; Okahandja Distr., Toggekry 250 ( Omatako Ranch ), 55 km NNW Okahandja, thornbush savana, BIOTA 04.101.2001.7.02.657, lux., 21° 30' S, 16° 43' E, 25 iv 2001, M. Uhlig & K. Ebert (38 ZMHB) ; Okahandja R., 1 m. S. Okahandja, 21° 59' S, 16° 52' E, 7 iv 1972, collector unknown (1 BMNH) ; Okahandja , small shaded pool in rock-hole, 21° 59' S, 16° 52' E, 21 v 1954, J. Balfour-Browne (5 BMNH) ; Okosongomingo 149, Otjiwarongo, SE 2017 Ca , 20° 27' S, 16° 39' E, 6–8 iii 1979, S. Louw, M-L. Penrith (1 SMW) ; Osona b. Okahandja , lux, 22° 1' S, 16° 56' E, 27 ii–2 iii 2001, U. Gollner (2 ZMHB) ; Waterberg Platopark, Okaisjukoma 2017 Ad , SMI 197, pool below waterfall, 20° 30' S, 17° 14' E, 18 ii 1983, S. Bethune (1 SMW) ; Windhoek, Eros Mt. , shore washing, elev. 1600 m, 22° 34' S, 17° 6' E, 10 ix 1974, Endrödy-Younga (#367)(169 TMSA) ; same locality, elev. 1600 m, 22° 34' S, 17° 6' E, 10 ix 1974, Endrödy-Younga (#365)(79 TMSA) ; Windhoek, Eros Mt. , sifting, elev. 1600 m, 22° 34' S, 17° 6' E, 10 ix 1974, Endrödy-Younga (#366) (2 TMSA) ; Windhoek , Furstenwalde R., 22° 34' S, 17° 5' E, 9 vii 1937, J. Omer Cooper (3 BMNH) ; Windhoek, In pools in rocky bed of stream, elev. 1654 m, 22° 34' S, 17° 5' E, 16 v 1954, J. Balfour-Browne (203) (4 BMNH) ; Windhoek , wet leaf litter in gully, 22° 34' S, 17° 5' E, 4–10 xi 1972, collector unknown (4 BMNH) ; Windhoek District, Niedersachen Dam, SE 2315 Bb , SMI 1690, under dead log, 23° 5' S, 15° 57' E, 4 iv 1986, B. A. Curtis (3 SMW) ; Okahandja , slow-flowing water, weed in patches, elev. 1340 m, 21° 59' S, 16° 52' E, 21 v 1954, J. Balfour-Browne (47 BMNH) ; Okarupa, 17 mi. E. Okahandja , pools in overflow stream from dam, much weed & algae, elev. 1493 m, 21° 59' S, 17° 10' E, 22 v 1954, J. Balfour-Browne (4 BMNH) ; Windhoek, In pools in rocky bed of stream, elev. 1654 m, 22° 34' S, 17° 5' E, 16 v 1954, J. Balfour-Browne (203) (71 BMNH) ; South Africa, Western Cape Province, Bredasdorp Dist., Arniston , 34° 39' S, 20° 13' E, 1-30 vii 1946, J. Glaholm (57 BMNH) .

Differential diagnosis. Very similar in size, color, coarse dorsal punctation, and habitus to H. multimurata ( Figs. 10 , 11 ). In both species the metaventral plaques are subtuberculate, each with medial surface shining, lateral surface with hydrofuge pubescence; this character will separate them from other species. The elytral punctation is often larger in H. namibiensis , whereas the pronotal punctation is often denser in H. multimurata . The aedeagi, which also show a relationship, must be examined for reliable determinations ( Figs. 12, 13 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.57/0.65; head 0.22/0.38; pronotum 0.37/0.49, PA 0.42, PB 0.43; elytra 0.99/0.65. Dorsum of head dark brown to piceous; pronotum brown around dark brown to piceous macula; elytra brown; legs light brown; maxillary palpi testaceous.

Frons punctures ca. 2xef, larger and denser near eyes than medially; interstices very weakly shining, 0.5–1xpd laterally, 1–3xpd medially. Clypeus mcr laterally, very finely sparsely punctulate medially. Mentum moderately densely finely punctulate, slightly concave medially near base, interstices shining; postmentum punctate, with deep depression on each side. Genae raised, shining, without posterior ridge.

Pronotum laterally slightly emarginate in front of and behind middle; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; coarsely densely punctate, punctures on disc much larger, deeper and denser than those of frons, interstices weakly shining, often narrow walls, at most 1xpd in a few places on disc; PF1 very shallow, confluent; PF2 very shallow; PF3 deep; PF4 very shallow.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margin moderately wide; on basal 1/3 punctures slightly smaller than largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, very weakly shining, on basal 1/3 ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/5/6. P1 laminate; median carina sinuate in profile. P2 l/ w ca. 5/2, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques subtuberculate, each with medial surface shining, lateral surface with hydrofuge pubescence, located at sides of deep median depression. Metaventrite without midlongitudinal carina between intercoxal process and median depression. AIS width at slightly arcuate posterior margin ca. 2x P2. Profemur with minute tubercle on lower surface near midlength. Pro- and mesotibiae slender, straight. Metatibiae very slender, very slightly arcuate in distal 2/3. Abdominal apex symmetrical; last tergite without notch. Female (microslide mount, n=1): last tergite moderately sharply rounded, with minute apicomedian notch, ca. 24 hooked setae, median gap narrow; gonocoxite not midlongitudinally divided, apical margin moderately sharply rounded, low transverse ridge evident at border of microreticulation; spermatheca type simple C shape.

Etymology. Named in reference to the geographical distribution, densely populated in Namibia.

Distribution. Currently known from many localities in Namibia, two localities in southernmost Angola, and one locality in the Western Cape Province, South Africa ( Fig. 70 ).

Figures

FIGURE 10. Hydraena namibiensis, holotype, dorsal and lateral habitus.

FIGURE 11. Hydraena multimurata, holotype, dorsal and lateral habitus.

FIGURES 12–13. Aedeagi of holotypes.

FIGURES 66–70. Geographical distributions of Hydraena species.