Hydraena caprivica, 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 : 44-47

Hydraena caprivica , new species

Figs. 31 (habitus), 33 (aedeagus), 70 (map)

Type material. Holotype (male): Namibia: East Caprivi: Katima Mulilo , lux, 17° 29' S, 24° 17' E, 8 iii 1992, M. Uhlig ( ZMHB).

Differential diagnosis. This is the smallest (ca. 1.20 mm) and most lightly colored species in the Clavicula Group ( Fig. 31 ). The aedeagus ( Fig. 33 ), which must be examined for reliable determinations, is very distinct from that of other members of the group; for this reason the species is only tentatively placed here. See also the diagnosis of H. armatura .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.20/0.51; head 0.18/0.30; pronotum 0.30/0.40, PA 0.33, PB 0.36; elytra 0.73/0.51.

Dorsum of head dark brown to piceous; pronotum light brown around dark brown to piceous macula; elytra brown; legs light brown; maxillary palpi testaceous.

Frons punctures ca. 1xef, slightly 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, interstices shining; postmentum contiguously punctulate. Genae raised, shining, without posterior ridge.

Pronotum laterally slightly emarginate behind middle; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; punctures on disc ca. 2xpd those of frons, interstices shining, 1–2xpd, punctures slightly denser at posterior; PF1 absent; PF2 very shallow; PF3 moderately deep; PF4 very shallow or obsolete.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. posterior 1/3; lateral explanate margin narrow; 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. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins forming moderately deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1.5/1/4/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 4/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques very narrow, straight, slightly converging toward one another anteriorly, weakly raised, 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. 2x P2. All tibiae slender, protibiae very slightly arcuate, meso- and metatibiae straight. Abdominal apex symmetrical; last tergite with small apicomedian notch.

Etymology. Named in reference to the geographical distribution.

Distribution. Currently known only from the type locality ( Fig. 70 ).

Figures

FIGURE 31. Hydraena caprivica, holotype, dorsal and lateral habitus.

FIGURES 32–33. Aedeagi of holotypes.

FIGURES 66–70. Geographical distributions of Hydraena species.