Hydraena armatura, 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 : 61-63

Hydraena armatura , new species

Figs. 43 (habitus), 45 (aedeagus), 75 (map)

Type material. Holotype (male): Zimbabwe: Tributary stream of the Mutoragundu River, 17° 7' S, 31° 2' E, 21 vi 1963, A. D. Harrison (SAL 427K) ( AMG) . Paratypes (88): Angola: Altoplano , Ongueria, in stagnant pools below waterfall, elev. 1615 m, 15° 19' S, 13° 32' E, 10 vi 1954, J. Balfour-Browne (255) (1 BMNH) ; Humpata , Altoplano, clear rapid stream, rocks & sandy bays, elev. 1828.8 m, 15° 19' S, 13° 28' E, 7–9 vi 1954, J. Balfour-Browne (248) (23 BMNH) ; Tampa , drying pools in sandy river bed; foul water, elev. 4000 m, 15° 30' S, 13° 27' E, 15 vi 1954, J. Balfour-Browne (274) (5 BMNH) ; Vana e Lombe, near Tampa, pools in dry river bed; rock and coarse sand, elev. 1372 m, 15° 30' S, 13° 30' E, 14 vi 1954, J. Balfour-Browne (269) (1 BMNH) ; Zimbabwe: Chindomora Reserve , Munwahuku Stream, collected where stream flowed between small bankside trees, Syzygium cordatum , 17° 31' S, 31° 9' E, 12 iv 1962, A. D. Harrison (SAL 153B) (1 AMG) ; Motoraseka Stream , 17° 13' S, 31° 0' E, 22 vii 1963, A. D. Harrison (SAL 464H.) (1 AMG) ; S. Rhodesia, Salisbury Dist. , Salisbury, 17 ix 1948, J. Omer-Cooper (5 BMNH) ; Salisbury (Highlands), grass along marsh, 17° 50' S, 31° 5' E, 4 xi 1960, I. M. Newell (5027) (11 MCZ) ; Tributary stream of Mutoragundu River, 17° 7' S, 31° 2' E, 22 vii 1963, A. D. Harrison (SAL 467K) (2 AMG) ; Tributary stream of the Mutoragundu River, 17° 7' S, 31° 2' E, 21 vi 1963, A. D. Harrison (SAL 427K) (2 AMG) ; Tributary stream of the Mutorangundu River, 17° 7' S, 31° 2' E, 22 vii 1963, A. D. Harrison (SAL 456N) (23 AMG) ; same locality, 17° 7' S, 31° 2' E, 22 vii 1963, A. D. Harrison (SAL 463N) (5 AMG) ; Tributary stream of the Poti River, 17° 20' S, 31° 31' E, 21 vi 1963, A. D. Harrison (SAL 429L) (3 AMG) ; Sewage oxidation pond, Stn. SOX 38F: POINT 1–1525S-2817E, 15° 25' S, 28° 17' E, (3 AMG) ; Sewage oxidation pond, Stn. SOX 42E: POINT 2–1525S-2817E, 15° 25' S, 28° 17' E, (2 AMG) .

Differential diagnosis. Very similar in size, metaventral plaques (ratios 1.5/1/4/4), and dorsal habitus to H. caprivica ( Figs. 31 , 43 ); differing therefrom by being slightly broader and slightly more coarsely punctate. The aedeagi of the two species, however, differ markedly ( Figs. 33 , 45 ). The aedeagus of H. armatura does not suggest placement in any of the groups.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.22/0.55; head 0.17/0.33; pronotum 0.32/0.45, PA 0.35, PB 0.40; elytra 0.76/0.55. Dorsum of head dark brown to piceous; pronotum light brown around dark brown to piceous macula; elytra brown; legs testaceous; maxillary palpi testaceous.

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 and postmentum moderately densely finely punctulate, dull. Genae raised, dull, without posterior ridge.

Pronotum laterally slightly emarginate in front of and behind middle; anterior margin straight behind eyes, emarginate behind frons, scintilla absent; moderately densely punctate, punctures on disc ca. 2xpd those of frons, interstices shining, 1–2xpd on disc; 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 moderately wide; 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. 0.5–1xpd, 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. 1.5/1/4/4. P1 laminate; median carina sinuate in profile. P2 l/w ca. 4/1, sides slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, oval, very slightly converging toward one another anteriorly, weakly raised, margins not strongly demarcated, 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 widest near midlength, inner margin with distal ½ emarginate, meso- and metatibiae straight. Abdominal apex symmetrical; last tergite with apicomedian notch. Female (microslide mount, n=1): last tergite moderately sharply rounded, with minute apicomedian notch, ca. 32 hooked setae in slightly irregular row; 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 complicated 'equipment' of the aedeagus.

Distribution. Currently known from Angola and Zimbabwe ( Fig. 75 ).

Figures

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

FIGURE 43. Hydraena armatura, holotype, dorsal and lateral habitus.

FIGURES 32–33. Aedeagi of holotypes.

FIGURES 44–45. Aedeagi of holotypes.

FIGURES 75–76. Geographical distributions of Hydraena species.