Hydraena camerocomplexa, 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 : 13-14

Hydraena camerocomplexa , new species

Figs. 3 , 13 (habitus), 13 (aedeagus), 42 (map)

Type Material. Holotype (male): “ Cameroon: Yaounde : Mt. Febe, 950 m., hygropetric, 10.iv.1982, P. D. Perkins collector” ( MCZ) . Paratype: Same data as holotype (1 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the small size (ca. 1.16 mm), the relatively large and wide pronotum (length/width ratio ca. 17/25), the moderately deep pronotal foveae, and the aedeagus ( Fig. 13 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.16/0.54; head width 0.33; pronotum 0.31/0.46, PA 0.39, PB 0.41; elytra 0.81/0.54. Habitus as illustrated ( Fig. 13 ). Dorsum light brown, head and pronotal macula darker (holotype is teneral), palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum densely moderately finely punctulate, interstices weakly shining; punctures of frons disc and pronotal disc ca. 1xef, interstices ca. 1–2xpd; punctures of clypeus very fine and dense. Labrum apicomedially excised, free margins rounded, weakly upturned. Pronotum relatively large and wide, length/width ratio ca. 17/25. Pronotum with anterior margin weakly emarginate over middle 1/2; antero- and posterolateral pronotal foveae shallow, posterosubmedial foveae moderately deep.

Elytra with posterior declivity very gradual, summit slightly beyond midlength; lateral explanate margins moderately wide; on basal 1/3 punctures slightly larger than largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width ca. 1xpd or less, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming very weak angle with one another. Venter: Mentum and postmentum finely sparsely punctulate, weakly shining. Genae very slightly raised, shining, with weak posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.5/2/2. P1 laminate; median carina weakly sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt. Plaques moderately narrow, straight, slightly convergent anteriorly, weakly raised, located at sides of moderately deep median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS weakly concave, width at straight posterior margin ca. 1.5x P2. Pro- meso- and metatibiae moderately stout, straight. Abdominal apex symmetrical, without apicomedian notch.

Distribution. Currently known only from the type locality ( Fig. 42 ).

Etymology. Named in reference to the known distribution and the very complex aedeagus.

Figures

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

FIGURE 13. Hydraena camerocomplexa, new species, habitus and aedeagus of holotype.

FIGURES 42–43. Geographical distributions of Cameroonian Hydraena.