Hydraena elephanta, 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 : 31-34

Hydraena elephanta , new species

Figs. 19 (habitus), 21 (aedeagus), 86 (map)

Type material. Holotype (male): Angola: Altoplano , Ongueria, in stagnant pools below waterfall, elev. 1615 m, 15° 19' S, 13° 32' E, 10 vi 1954, J. Balfour-Browne (255) ( BMNH) . Paratypes (64): Angola: Same data as holotype (1 BMNH) . Senhora do Monte , Sa da Bandeira, sous des pierres, elev. 563 m, 14° 42' S, 13° 49' E, 22 ix 1949, A. de Barros Machado (61 BMNH) ; Serra do Moco , Luimbale, elev. 700 m, 12° 14' S, 15° 18' E, 6 ix 1949, A. de Barros Machado (1 BMNH) ; Namibia: Namib-Naukluft NP: Naukluft River, Phragmites grass + leaf litter, shore washing + sievings, 24° 15.78' S, 16° 14.08' E, 29-30 xi 1997, M. Uhlig (1 ZMHB) .

Differential diagnosis. Recognized by the piceous pronotal disc, which has large and deep PF2 foveae that are shallowly confluent in the midline. Each dorsal puncture has a distinctive, short recumbent seta. The aedeagus shows some similarity to that of H. uniforma ( Figs. 20, 21 ), but that species has non-serial elytral punctures, and the dorsal habitus of the two species differ distinctively ( Figs. 18 , 19 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.64/0.70; head 0.23/0.40; pronotum 0.42/0.52, PA 0.41, PB 0.45; elytra 1.02/0.70.

Dorsum of head dark brown to piceous; pronotum brown to dark brown near margins, gradually grading to piceous on disc; elytra dark brown; legs brown; maxillary palpi light brown. Each dorsal puncture with distinctive, short recumbent seta.

Frons punctures ca. 1xef, 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 slightly larger and deeper than those of frons, interstices shining, 1–2xpd, punctures slightly denser at anterior and posterior; PF1 very shallow, confluent in midline; PF2 deep, shallowly confluent in midline; PF3 deep; PF4 shallow.

Elytra weakly arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margin moderately wide; on basal 1/3 punctures ca. 1–2xpd largest pronotal punctures, punctures becoming finer and more widely spaced toward posterior. Intervals not raised, shining, on basal 1/3 ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/1/4/5. 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 small, elongate oval, parallel, very 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, pro- and metatibiae very slightly arcuate, mesotibiae straight. Abdominal apex symmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1): last tergite moderately broadly rounded, with minute apicomedian notch, ca. 28 hooked setae in double row; 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 elephant-like shape of the aedeagal apex.

Distribution. Currently known from Angola and Namibia ( Fig. 86 ).

Figures

FIGURE 18. Hydraena uniforma, holotype, dorsal and lateral habitus.

FIGURE 19. Hydraena elephanta, holotype, dorsal and lateral habitus.

FIGURES 20–21. Aedeagi of holotypes.

FIGURES 85–88. Geographical distributions of Hydraena species.