Hydraena injectiva, 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 : 34-35

Hydraena injectiva , new species

Figs. 22 (habitus), 24 (aedeagus), 84 (map)

Type material. Holotype (male): South Africa: Mpumalanga Province, Nelshoogte gallery forest below St., shore washing, 25° 51' S, 30° 53' E, 2 xii 1986, Endrödy-Younga (#2343) ( TMSA) . Paratype: South Africa: KwaZulu-Natal Province, nr. Drummond , small stream, stony and weedy pools, elev. 457.2 m, 30° 50' S, 30° 25' E, 1 iv 1954, J. Balfour-Browne (128) (1 BMNH) .

Differential diagnosis. This is the smallest member of the Namibiensis Group (ca. 1.31 mm), and can be differentiated from others by the size and the sparser pronotal punctation. The dorsal habitus is somewhat similar to that of H. vadosa ( Figs. 22 , 34 ), but that species is larger (ca. 1.69 vs. 1.31 mm), has different metaventral plaques, and the aedeagi of the two species differ markedly ( Figs. 24 , 36 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.31/0.54; head 0.22/0.34; pronotum 0.34/0.45, PA 0.36, PB 0.37; elytra 0.78/0.54. Dorsum of piceous; pronotum brown around dark brown macula; elytra brown; legs brown; maxillary palpi testaceous.

Frons punctures ca. 1xef, denser near eyes than medially; interstices weakly shining, 0.5–1xpd laterally, 1– 4xpd medially. Clypeus mcr laterally, very finely sparsely punctulate medially. Mentum and postmentum finely punctulate, interstices shining. 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 slightly larger and deeper than those of frons, interstices shining, 1–4xpd; PF1 absent; PF2 very shallow; PF3 shallow; 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 ca. 1xpd largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, 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 deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/0.5/4/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques very small, oval, 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, pro- and mesotibiae straight, metatibiae very slightly arcuate. Abdominal apex symmetrical; last tergite with very small apicomedian notch.

Etymology. Named in reference to the needle-like apex of the aedeagus.

Distribution. Currently known only from one locality each in Mpumalanga and KwaZulu-Natal Provinces, South Africa ( Fig. 84 ).

Figures

FIGURE 22. Hydraena injectiva, holotype, dorsal and lateral habitus.

FIGURE 34. Hydraena vadosa, holotype, dorsal and lateral habitus.

FIGURES 24–25. Aedeagi of holotypes.

FIGURES 36–37. Aedeagi of holotypes.

FIGURES 81–84. Geographical distributions of Hydraena species.