Hydraena pisciforma, 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 : 25-27

Hydraena pisciforma , new species

Figs. 14 (habitus), 16 (aedeagus), 82 (map)

Type material. Holotype (male): South Africa: Mpumalanga Province, Kruger National Park, Skukuza, Sabie River , shore washing, 24° 57' S, 30° 42' E, 22 ii 1995, Endrödy-Younga (3110) ( TMSA) . Paratypes (82): South Africa: Free State Province, Guernsey Farm, 15 km E. Klaserie , flight intercept trap, elev. 500 m, 24° 5' S, 31° 15' E, 19–31 xii 1985, H. & A. Howden (2 CMNO) ; Sewage oxidation pond, Stn. SOX 42E: POINT 2, 25° 15' S, 28° 17' E, (1 AMG) ; KwaZulu-Natal Province, Itala Game Res.: Thalu , river banks, 27° 30' S, 31° 20' E, 27 i 1994, M. Uhlig (3 ZMHB) ; Limpopo Province, Doornfontein , grassy pool, much blanket algae, elev. 957 m, 24° 48' S, 27° 30' E, 17 iv 1954, J. Balfour-Browne (168a) (5 BMNH) ; Waterberg, Matlabas River , shore washing, 24° 25' S, 27° 36' E, 6 x 1995, Endrödy-Younga & Bellamy (3151) (4 TMSA) ; Waterberg, Matlabas River , water collecting, 24° 25' S, 27° 36' E, 6 x 1995, Endrödy-Younga & Bellamy (3150) (2 TMSA) ; Mpumalanga Province, Albany Museum catalog GEN 756L: 230330S-301500E, 23° 3' S, 30° 15' E, (3 AMG) ; Bundu Inn , shore washing, 25° 28' S, 28° 55' E, 24 iii 1974, Endrödy-Younga (#304) (15 TMSA) ; E. Transvaal, Blyderiver Canyon , shore washing, 24° 35' S, 30° 49' E, 2 v 1981, Endrödy-Younga (#1765) (13 TMSA) ; Kruger National Park, Pretoriuskop Kruger G, airplancton, 25° 6' S, 31° 23' E, 20 ii 1995, Endrödy-Younga (3103) (5 TMSA) ; Kruger National Park, Skukuza , 12 km S, UV light, 25° 4' S, 31° 37' E, 6 iii 1996, Endrödy-Younga (3217) (7 TMSA) ; Kruger National Park, Skukuza res. camp, UV light and trap, 24° 59' S, 31° 35' E, 25 ii 1995, Endrödy-Younga (3120) (1 TMSA) ; Kruger National Park, Skukuza, Sabie River , shore washing, 24° 57' S, 30° 42' E, 22 ii 1995, Endrödy-Younga (3110) (9 TMSA) ; N. Transvaal, Louis Trichardt , 22k W., river stones, 23° 2' S, 29° 40' E, 1–5 iv 1976, Endrödy-Younga & L. Schulze (#1125) (1 TMSA) ; N. Transvaal, Soutpansberg, Entabeni , river stones, 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1135) (1 TMSA) ; N. Transvaal, Soutpansberg, Entabeni , shore washing, 22° 59' S, 30° 15' E, 21 iv 1976, Endrödy-Younga (#1136) (4 TMSA) ; Nelshoogte gallery forest below St. , shore washing, 25° 51' S, 30° 53' E, 2 xii 1986, Endrödy-Younga (#2343) (6 TMSA) .

Differential diagnosis. This species is dorsally similar to H. natiforma , having very coarsely and densely punctate pronotum and elytra ( Figs. 14 , 15 ). It is slightly smaller (ca. 1.50 vs. 1.62 mm), and the pronotal margins are more lightly colored than in H. natiforma . The most distinctive difference is in the shape of the metaventral plaques, which converge toward one another anteriorly in H. pisciforma , whereas in H. natiforma the plaques distinctively diverge anteriorly and are separated by a very deep depression. The aedeagi ( Figs. 16, 17 ) also show a relationship.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.50/0.62; head 0.23/0.37; pronotum 0.37/0.47, PA 0.39, PB 0.43; elytra 0.94/0.62.

Dorsum of head dark brown to piceous; pronotum light brown to testaceous around dark brown to piceous macula; elytra brown; legs testaceous; maxillary palpi testaceous, except distal ½ of last palpomere slightly darker.

Frons punctures ca. 2xef, larger and denser near eyes than medially; interstices weakly shining, 0.5–1xpd laterally, 1–2xpd medially. Clypeus mcr laterally, very finely sparsely punctulate medially. Mentum moderately densely finely punctulate, concave medially near base, interstices shining; postmentum densely moderately coarsely punctate, with 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 often narrow walls, at most 1xpd in a few places on disc; PF1 absent; PF2 very shallow; PF3 deep; PF4 very shallow or obsolete.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. posterior 1/3; 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. narrow walls to 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. 2/1.5/6/5. P1 laminate; median carina sinuate in profile. P2 l/w ca. 5/2, sides slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques moderately wide, slightly converging toward one another anteriorly, not raised, 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. Protibiae lower surface excavate in distal ¼, prominent spine at base of excavation; mesotibiae straight; metatibiae slightly arcuate in ca. distal 4/5. Abdominal apex very slightly asymmetrical; last tergite with slightly off center notch. Female (microslide mount, n=1): last tergite moderately sharply rounded, with minute apicomedian notch, ca. 24 hooked setae in slightly irregular row, set back from margin ca. ½ their length; gonocoxite not midlongitudinally divided, apical margin moderately sharply rounded, low transverse ridge evident at border of microreticulation; spermatheca simple, type C shape.

Etymology. Named in reference to the fish-like shape of the aedeagus.

Distribution. Currently known from several localities in northeastern South Africa ( Fig. 82 ).

Figures

FIGURE 14. Hydraena pisciforma, holotype, dorsal and lateral habitus.

FIGURE 15. Hydraena natiforma, holotype, dorsal and lateral habitus.

FIGURES 16–17. Aedeagi of holotypes.

FIGURES 81–84. Geographical distributions of Hydraena species.