Hydraena biseptosa, new species

Figs. 51 (habitus), 53 (aedeagus), 79 (map)

Type material. Holotype (male): South Africa: Mpumalanga Province, Soutpansberg, Entabeni, shore washing, 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1136) (TMSA). Paratypes (421): South Africa: Eastern Cape Province, 20 km W Port Shepstone, Oribi Gorge nr. Paddock, 30° 45' S, 30° 15' E, 12 iii 1997, Hess & Heckes (30) (2 NMW); Transkei: S. coast, Dwesa for. res., window trap, 7 days , 32° 17' S, 28° 50' E, 26 ii 1985, Endrödy-Younga (#2166) (14 TMSA); Free State Province, Kareefontein nr. Nylstroom, rapid stream over rock and gravel, elev. 1460 m , 28° 25' S, 26° 53' E, 16 iv 1954, J. Balfour-Browne (164) (6 BMNH); Limpopo Province, Blauberg, Beauly River, from boulder and fine gravel, fast water, elev. 1143 m , 23° 8' S, 28° 56' E, 18 iv 1954, J. Balfour-Browne (13 BMNH); Doornfontein, grassy pool, much blanket algae, elev. 957 m , 24° 48' S, 27° 30' E, 17 iv 1954, J. Balfour-Browne (168a) (69 BMNH); Doornfontein, small muddy water hole, little weed, elev. 957 m , 24° 48' S, 27° 30' E, 17 iv 1954, J. Balfour-Browne (168) (1 BMNH); Waterberg, Matlabas River, shore washing , 24° 25' S, 27° 36' E, 6 x 1995, Endrödy-Younga & Bellamy (3151) (13 TMSA); Mpumalanga Province, E. Transvaal, Hazyview, airplankton , 25° 4' S, 31° 7' E, 3 iv 1990, S. Endrödy-Younga (2777) (1 TMSA); E. Transvaal, Potholes, shore washing, elev. 1050 m , 24° 31' S, 30° 50' E, 4 v 1981, Endrödy-Younga (#1774) (6 TMSA); Khalava, Mutale River, Camp Drift, sandy edges, elev. 1249 m , 22° 30' S, 30° 54' E, 25 iv 1954, J. Balfour-Browne (194) (32 BMNH); Mpumalanga, Graskop 28 km N, wet rockface , 24° 43' S, 30° 51' E, 4 ii 1997, Endrödy-Younga (3276) (7 TMSA); N. Transvaal, Entabeni Forest Reserve, airplankton, forest , 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1137) (1 TMSA); N. Transvaal, Louis Trichardt, 22k W., river stones , 23° 2' S, 29° 40' E, 1–5 iv 1976, Endrödy-Younga & L. Schulze (#1125) (2 TMSA); N. Transvaal, Soutpansberg, Entabeni, river stones , 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1135) (48 TMSA); N. Transvaal, Soutpansberg, Entabeni, shore washing , 22° 58' S, 30° 15' E, 15 iii 1973, Endrödy-Younga (#56) (3 TMSA); Soutpansberg, Entabeni, shore washing,, 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1136) (83 TMSA); Olifants-Klip River System, Stn. OKS 71H: 2537S-2913E , 25° 37' S, 29° 13' E, (1 AMG); Zoutpansberg Dist., Khalava: Mutale River, in side gravels and muddy pools, elev. 914.4 m , 22° 58' S, 30° 15' E, 24 iv 1954, J. Balfour-Browne (191) (5 BMNH); Zoutpansberg Dist., Louis Trichardt, 23° 0' S, 30° 0' E, 27 viii 1948, J. Omer-Cooper (1 BMNH); Zoutpansberg Dist., Mutshindudi River, in silty edges at drift, elev. 1067 m , 22° 58' S, 30° 15' E, 25 iv 1954, J. Balfour-Browne (195) (1 BMNH); Zoutpansberg; Look Out, Hanglip District, in brown water seepage in turf, elev. 1341 m , 22° 58' S, 30° 15' E, 23 iv 1954, J. Balfour-Browne (24 BMNH); Zoutpansberg; Look Out, Hanglip District, in clear rapid stream with sandy bottom, elev. 1340 m , 22° 58' S, 30° 15' E, 23 iv 1954, J. Balfour-Browne (185) (80 BMNH); North West Province, Magaliesbg., Tonquane, water collection , 25° 15' S, 27° 19' E, 8 iv 1973, Endrödy-Younga (#84) (8 TMSA) .

Differential diagnosis. Differentiated from other species by the combination of the very densely coarsely punctate dorsum, the deep pronotal foveae, the subserial or random elytral punctation, and the broadly rounded elytral apices (Fig. 51). The metaventral plaques are narrow, almost twice the width separating them (ratios 2/1/7/ 4). The aedeagus (Fig. 53) does not suggest placement in any of the groups.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.65/0.71; head 0.27/0.42; pronotum 0.40/0.52, PA 0.44, PB 0.50; elytra 1.00/0.71.

Dorsum of head dark brown to piceous; pronotum and elytra dark brown; legs and maxillary palpi brown.

Frons concave near eyes; punctures ca. 1xef; interstices weakly shining, 0.5–1xpd. Clypeus mcr laterally, sparsely punctulate medially. Mentum very sparsely finely punctulate, weakly shining; postmentum very finely contiguously micropunctulate in median concavity, surrounding areas smooth, shining. Genae raised, weakly shining, without posterior ridge.

Pronotum laterally slightly emarginate in front of and behind middle; anterior margin straight behind eyes, very weakly bisinuate behind frons, scintilla absent; coarsely densely punctate, punctures on disc larger, deeper and denser than those of frons, interstices often narrow walls, at most on disc; PF1 moderately deep, confluent and extended posteriorly in midline; PF2 large and deep; PF3 deep; PF4 moderately deep.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. posterior 1/3; lateral explanate margin moderately wide; punctures often subserial, sometimes random; on basal 1/3 punctures slightly larger than largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Interstices between punctures very weakly shining, on basal 1/3 ca. 0.5–1xpd, as are interstices between punctures of a row. Apices in dorsal aspect separately rounded, in posterior aspect margins forming deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/7/4. P1 laminate; median carina very weakly sinuate in profile. P2 l/w ca. 5/2, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight, slightly converging toward one another anteriorly, weakly raised, located at sides of moderately deep median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 2x P2. All protibiae slender, straight. Abdominal apex slightly asymmetrical; last tergite with small, slightly off center notch. Female (microslide mount, n=1): last tergite moderately broadly rounded, with minute apicomedian dark line, but no V-shaped incision, ca. 24 hooked setae, some contiguous; gonocoxite not midlongitudinally divided, apical margin moderately broadly rounded, no transverse ridge evident at border of microreticulation; spermatheca simple, type C shape.

Etymology. Named in reference to the seven foveae of the pronotum, and the seven processes of the aedeagus.

Distribution. Many localities, rather widely distributed, in eastern South Africa (Fig. 79).