Hydraena camerocontrasta, 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 : 9-10

Hydraena camerocontrasta , new species

Figs. 1 , 7 (habitus), 7 (aedeagus), 43 (map)

Type Material. Holotype (male): Cameroon : Northwest Province. “ BRITISH CAMEROONS. / Mamfe, 7-11.i.1949 / B. Malkin coll. // Rain forest; clear stream / Gravel and sand” ( UKNHM).

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the light brown clypeus contrasting with dark brown frons, the frons shallowly concave between median area and eye, and the male genitalia ( Fig. 7 ). Also refer to the diagnosis of H. camerocorona for comments on the male genitalia.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.22/0.54; head width 0.30; pronotum 0.29/0.44, PA 0.36, PB 0.39; elytra 0.76/0.54. Habitus as illustrated ( Fig. 7 ). Dorsum brown to dark brown, frons and pronotal disc darker, light brown clypeus contrasting with dark brown frons, palpi testaceous, tip of last palpomere not darker. Frons shallowly concave between median area and eye. Dorsum of head and pronotum finely sparsely punctulate, interstices shining; punctures of frons disc and pronotal disc ca. 1xef, interstices ca. 1–3xpd; clypeus dull, punctures very fine and dense. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral, posterolateral, and posterosubmedial pronotal foveae moderately deep

Elytra with summit of posterior declivity at or very near posterior 1/3, where elytra transversely quite convex; lateral explanate margins narrow; on basal 1/3 punctures slightly larger than 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 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. Abdominal apex with slightly off-center apical notch.

Venter: Mentum and postmentum moderately finely punctulate, shining. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.5/2/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides parallel or slightly diverging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight, parallel, raised very slightly, located at sides of deep median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at straight posterior margin ca. 2x P2. All tibiae slender, protibia slightly arcuate, meso- and metatibiae straight. Abdominal apex with off center apical notch.

Distribution. Currently known only from the type locality ( Fig. 43 ).

Etymology. Named in reference to the known distribution and the contrasting sizes of the parameres: right very elongate, left just a nub.

Figures

FIGURE 7. Hydraena camerocontrasta, new species, habitus and aedeagus of holotype.

FIGURES 1–2. 1. Dorsal habitus of Cameroonian species of Hydraena in Aedeagal Species Group 1; 2. Representative aedeagi of Aedeagal Species Groups 1–4.

FIGURES 42–43. Geographical distributions of Cameroonian Hydraena.