Hydraena camerocurvata, Perkins, 2022

Perkins, Philip D., 2022, Thirty-three new species of water beetles in the genus Hydraena Kugelann from Cameroon (Coleoptera: Hydraenidae), Zootaxa 5203 (1), pp. 1-66 : 15-16

Hydraena camerocurvata , new species

Figs. 3 , 16 (habitus), 16 (aedeagus), 40 (map)

Type Material. Holotype (male): “ Cameroon: N. W. Prov., 7 km. E. Bamenda, stream, 30.i.1982, leg. P. D. Perkins ” ( MCZ) . Paratype: Same data as holotype (1 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the ovate body form, the transversely convex pronotum, the posterosubmedial foveae shallow, confluent medially forming U-shaped impression, the very narrow P2, and the aedeagus ( Fig. 16 ). Differentiation from other similarly shaped members of Aedeagal Species Group 2 will require careful examination of the aedeagus.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.30/0.57; head width 0.34; pronotum 0.31/0.49, PA 0.39, PB 0.41; elytra 0.80/0.57. Habitus as illustrated ( Fig. 16 ). Body form ovate. Dorsum generally brown to dark brown, maxillary palpi, labrum and clypeus testaceous, pronotum with diffusely margined weakly defined macula. Dorsum of head and pronotum moderately coarsely, moderately densely punctulate, frons punctures distinctly finer and less dense than pronotal punctures, interstices shining; punctures of frons disc and pronotal disc ca. 1–2xef, interstices ca. 1–2xpd; punctures of clypeus fine, moderately dense, interstices shining medially, dull laterally. Labrum apicomedially excised, free margins rounded, weakly upturned. Pronotum transversely convex, anterior margin weakly emarginate over middle 1/2; anterolateral and posterolateral foveae shallow, posterosubmedial foveae shallow, confluent medially forming U-shaped impression, anteromedial fovea moderately deep.

Elytra with summit of posterior declivity at about posterior 1/3; lateral explanate margins wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior, each puncture with very short and very fine seta. Intervals not raised, width ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins not forming angle with one another.

Venter: Mentum and postmentum sparsely very finely punctulate, shining. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/3/3. P1 laminate; median carina sinuate in profile. P2 very narrow, l/w ca. 4/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, very slightly arcuate, tapering anteriorly and slightly converging toward one another anteriorly, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 3x P2. All tibiae stout. Protibia widened near midlength, very slightly arcuate. Meso- and metatibiae straight. Abdominal apex symmetrical, last tergite rounded, without apicomedian notch, last ventrite emarginate.

Distribution. Currently known only from the type locality ( Fig. 40 ).

Etymology. Named in reference to the known distribution, and to the ovate body form and very curvaceous aedeagus.

Figures

FIGURE 3. Dorsal habitus of Cameroonian species of Hydraena in Aedeagal Species Group 2.

FIGURE 16. Hydraena camerocurvata, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.