Hydraena monikae Jäch & Diaz

PERKINS, PHILIP D., 2014, A revision of the water beetle genus Hydraena Kugelann for southern Africa (Coleoptera: Hydraenidae), Zootaxa 3758 (1), pp. 1-92 : 75-76

Hydraena monikae Jäch & Diaz

Figs. 58 (habitus), 61 (aedeagus), 67 (map)

Type material. Holotype (male): South Africa: Western Cape Province, Hex River Mountains , ca. 7 km SW Ceres. Verbatim label data is given in the original description.

Material examined (232): South Africa: Western Cape Province, 2 mi SW of Citrusdal , elev. 150 m, 32° 37' S, 19° ' E, 30 iv 1958, E. S. Ross & R. E. Leech (6 CAS) ; Assagaaibos Road Station 1 (GBG 18M), marginal vegetation, 33° 59' S, 19° 3' E, 23 vi 1950 (1 AMG) ; Assagaibos Road Station 1 (GBG 2S), marginal vegetation, 33° 59' S, 19° 3' E, 24 v 1950 (3 AMG) ; Caledon District, Elgin Forest Reserve, Palmiet River , upper parts, 33° 45' S, 22° 58' E, 10 iii 1954, J. Balfour-Browne (1 BMNH) ; Cape Province (western), Cape District, Du Toit's Kloof , under stones in tiny spring and among algae in bottom gravel, 33° 43' S, 19° 11' E, 8 xi 1949, B. Malkin (12 BMNH) ; Hermon Road Bridge Station 13 (GBG 97B), stones in current, 33° 27' S, 19° 1' E, 27 ix 1950 (4 AMG) ; Klein Berg River (tributary of middle Great Berg River), stone in current, Stn. 15, 110B, 33° 13' S, 18° 58' E, 12 x 1950, collector unknown (4 AMG) ; Krom River Stn 4, Stellenbosch ; ERS 18A, emergent vegetation, 33° 56' S, 18° 50' E, (1 AMG) ; Malmesbury District, Kalabaskraal , slow weedy stream, elev. 106 m, 33° 28' S, 18° 43' E, 27 vii 1954, J. Balfour-Browne (Stn. No. 328) (1 BMNH) ; Paarl District, Du Toit’s Kloof , elev. 1067 m, 33° 44' S, 19° 11' E, 5 iii 1954, J. Balfour-Browne (15) (16 BMNH) ; Paarl District, Du Toit’s Kloof , elev. 762 m, 33° 43' S, 19° 11' E, 5 iii 1954, collector not given (2 SAM) ; Paarl , shallow weedy rivulet, elev. 128 m, 33° 45' S, 18° 58' E, 10 viii 1954, J. Balfour-Browne (353) (50 BMNH) ; Paarl, Small , shallow, muddy ephemeral pool, elev. 128 m, 33° 45' S, 18° 58' E, 10 viii 1954, J. Balfour-Browne (352) (2 BMNH) ; Piketberg Station 18; Albany Museum catalog GBG 299D, marginal vegetation, 32° 53' S, 18° 44' E, 25 vi 1951 (1 AMG) ; Piketberg Station 18; Albany Museum catalog GBG 447A, marginal vegetation, 32° 53' S, 18° 44' E, 1 xii 1951 (1 AMG) ; S. W. Cape, Bainskloof, Breë R., shore washing, 33° 30' S, 19° 10' E, 10 xi 1973, Endrödy-Younga (#227) (12 TMSA) ; S. W. Cape Mts., Hawequas SE, water coll. in rapid, elev. 1100 m, 33° 41' S, 19° 6' E, 5 xi 1973, Endrödy-Younga (#203) (70 TMSA) ; Skurfteburg, Alfreds Berg Pass, NNW Ceres , 33° 16' S, 19° 18' E, 12 ii 1951, Brinck & Rudebeck (181) (6 LUM) ; W. Cape, Hawequas , shore washing, 33° 34' S, 19° 8' E, 10 xi 1973, Endrödy-Younga (#226) (35 TMSA) ; Wellington Road Bridge Station 12 (GBG 396C), 33° 35' S, 19° 1' E, 20 x 1951 (5 AMG) .

Differential diagnosis. Dorsal habitus somewhat similar to H. duodecimata ( Figs. 58 , 59 ); differing therefrom by having a slightly wider body form, lacking strongly carinate elytral intervals, and having shorter metaventral plaques (ratios 2/2/10/3 vs. 2/2/17/3). The aedeagi of the two species distinctively differ ( Figs. 61, 62 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.92/0.82; head 0.29/0.45; pronotum 0.43/0.57, PA 0.46, PB 0.49; elytra 1.21/0.82.

Dorsum of head dark brown to piceous; pronotum dark brown around margins, grading gradually to piceous disc; elytra, legs, and maxillary palpi brown. Dorsum coarsely densely punctate.

Frons punctures ca. 3–4xef; interstices narrow walls, very weakly shining. Clypeus mcr laterally, coarsely punctate medially, punctures slightly smaller than those of frons. Mentum and postmentum densely coarsely punctate; mentum with basomedian depression. Genae raised, densely punctate, dull, with posterior ridge.

Pronotum laterally slightly emarginate in front of and behind middle; anterior margin straight behind eyes, shallowly emarginate behind frons, scintilla absent; coarsely densely punctate, punctures on disc slightly larger than those of frons, separated by narrow walls; PF1 absent; PF2 very shallow; PF3 deep; PF4 shallow.

Elytra moderately widely arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margin moderately wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming slightly finer and more widely spaced toward posterior. Intervals 2, 4 and 6 very slightly raised, dull, on basal 1/3 narrow walls to 0.5xpd, as are interstices between punctures of a row. Apices in dorsal aspect weakly separately rounded, in posterior aspect margins do not form angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 2/2/10/3. P1 slightly wider than laminate; median carina very low, very weakly sinuate in profile. P2 l/w ca. 4/1, sides converging toward narrow apex, apex raised slightly above mesoventral intercoxal process. Plaques large, punctate along margins, converging toward one another and very narrowly separated anteriorly, weakly raised, located at sides of moderately deep median longitudinal depression. Metaventrite with depression lateral to each plaque; without midlongitudinal carina between intercoxal process and median depression. AIS subtriangular, deeply concave, width at slightly arcuate posterior margin ca. 1x P2. All tibiae slender, straight. Abdominal apex symmetrical; last tergite with minute apicomedian incision.

Distribution. Currently known from the Western Cape Province, with several localities in the west, and one locality in the east ( Fig. 67 ).

Figures

FIGURE 58. Hydraena monikae, holotype, dorsal and lateral habitus.

FIGURE 59. Hydraena duodecimata, holotype, dorsal and lateral habitus.

FIGURES 61–63. Aedeagi of H. monikae (non-type), H. duodecimata (holotype), and H. sebastiani (holotype).

FIGURES 66–70. Geographical distributions of Hydraena species.