Hydraena zimbabwensis, 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 : 40-43

Hydraena zimbabwensis , new species

Figs. 27 (habitus), 29 (aedeagus), 65 (map)

Type material. Holotype (male): Zimbabwe: Matapos [Matobo] National Park, 20° 33' S, 28° 30' E, 1–2 iv 1968, P. J. Spangler ( USNM) . Paratypes: Zimbabwe, Same data as holotype (3 USNM) .

Differential diagnosis. Quite similar in dorsal habitus to H. mpumalanga ( Figs. 27 , 30 ); differing therefrom in slightly smaller body size (ca. 1.37 vs. 1.42 mm), shorter elytra compared to length of the pronotum, and oval instead of elongate metaventral plaques. The aedeagi also show a relationship in basic form, while differing in several details ( Figs. 29 , 32 ). See also the diagnosis of H. clavicula .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.37/0.58; head 0.22/0.35; pronotum 0.33/0.46, PA 0.36, PB 0.39; elytra 0.80/0.58. Dorsum of head dark brown to piceous; pronotum dark brown around margins, grading gradually to piceous disc; elytra dark brown; legs dark brown; maxillary palpi brown.

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 very sparsely very finely punctulate, weakly shining, with moderately large basomedian impression; 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; moderately densely punctate, punctures on disc slightly larger, deeper and denser than those of frons, interstices 1–2xpd on disc; PF1 absent; PF2 very shallow; PF3 deep; PF4 very shallow or obsolete.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margin moderately wide; on basal 1/3 punctures slightly larger than largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, shining, on basal 1/3 ca. 0.5–1xpd, 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. 2/1/2/4. 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 very small, very weakly raised, located at sides of shallow 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, straight; metatibia with sparse row of very short spines on inner margin. Abdominal apex symmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1): last tergite moderately broadly rounded, with minute apicomedian notch, ca. 18 hooked setae, very slender, widely spaced, and set back from margin about ½ length of setae; 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 geographical distribution.

Distribution. Currently known only from the type locality ( Fig. 65 ).

Figures

FIGURE 27. Hydraena zimbabwensis, holotype, dorsal and lateral habitus.

FIGURE 30. Hydraena mpumalanga, holotype, dorsal and lateral habitus.

FIGURES 28–29. Aedeagi of holotypes.

FIGURES 32–33. Aedeagi of holotypes.

FIGURES 64–65. 64. All known collecting localities for southern African Hydraena. 65. Geographical distributions of Hydraena species.