Hydraena natiforma, 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 : 27-28

Hydraena natiforma , new species

Figs. 15 (habitus), 17 (aedeagus), 81 (map)

Type material. Holotype (male): South Africa: Free State Province, Kruger Nat’l Park, Pretariuskop , 23° 50' S, 31° 30' E, 20–21 ii 1968, P. J. Spangler ( USNM) . Paratypes (13): South Africa: Free State Province, Same data as holotype (4 USNM) ; 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 (173) (1 BMNH) ; Transvaal, Shingwidze River , pools in dry sand bed, elev. 550 m, 23° 53' S, 32° 17' E, 26 iv 1954, J. Balfour-Browne (198) (7 BMNH) ; Zimbabwe: Matopos [Matabo] National Park , 20° 33' S, 28° 30' E, 1-2 iv 1968, P. J. Spangler (1 USNM) .

Differential diagnosis. Refer to the diagnosis of H. pisciforma .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.62/0.67; head 0.23/0.38; pronotum 0.40/0.50, PA 0.43, PB 0.50; elytra 1.01/0.67. Dorsum of head piceous; pronotum brown around dark brown to piceous macula; elytra brown; legs brown; maxillary palpi light brown, except distal ½ of last palpomere slightly darker.

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

Pronotum laterally slightly emarginate 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, especially in area opposite posterior declivity; on basal 1/3 punctures ca. 1xpd of 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 0.5xpd, as are interstices between punctures of a row. Each elytron with very low umbo located on posterior declivity, in area of series 6 to 8. 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; s measured anteriorly) ca. 2/2/6/8. P1 laminate; median carina sinuate in profile. P2 l/w ca. 5/2, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques moderately wide, markedly diverging anteriorly from one another, not raised, located at sides of very deep, wide median depression. Metaventrite without midlongitudinal carina between intercoxal process and median depression. AIS width at slightly arcuate posterior margin ca. 2x P2. Pro- and mesotibiae straight; metatibiae slightly arcuate in ca. distal 4/5, inner margin with sparse, moderately long setae that lie flat on cuticle. Abdominal apex very slightly asymmetrical; last tergite with slightly off center notch. Female (microslide mount, n=1): last tergite moderately broadly rounded, with minute apicomedian notch, ca. 20 hooked setae, in single row, not contiguous; 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 aedeagal shape, which resembles a swimming fish.

Distribution. Currently known from three localities in northeastern South Africa, and one locality in southern Zimbabwe ( Fig. 81 ).

Figures

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

FIGURES 81–84. Geographical distributions of Hydraena species.