Hydraena camerojocula, 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 : 11

Hydraena camerojocula , new species

Figs. 1 , 9 (habitus), 9 (aedeagus), 41 (map)

Type Material. Holotype (male): “ Cameroon: C. S. Prov., 15 km. S. Mbalmayo, Nyong River , ex. leaves at margin, 22.v.1982, leg. P. D. Perkins ” ( MCZ).

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the posterosubmedian foveae moderately deep, medially confluent forming U-shaped depression, the metaventral plaques moderately narrow posteriorly, tapering to point anteriorly, and the aedeagus ( Fig. 9 ). Dorsal habitus similar to other species in Aedeagal Group 1; reliable determinations will require examination of the male genitalia.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.35/0.60; head width 0.36; pronotum 0.32/0.46, PA 0.37, PB 0.41; elytra 0.82/0.60. Habitus as illustrated ( Fig. 9 ). Dorsum generally dark brown, except labrum, clypeus and anterolateral angles of pronotum lighter, palpi testaceous, tip of last palpomere not darker. Frons moderately finely and moderately densely punctulate, pronotum moderately coarsely, moderately densely punctate, punctures much larger than those of frons, interstices shining, ca. 1–2xpd. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral foveae deep, posterolateral foveae very shallow, posterosubmedian foveae moderately deep, medially confluent forming U-shaped depression.

Elytra with summit of posterior declivity slightly beyond midlength; lateral explanate margins moderately wide; on basal 1/3 punctures ca. 1xpd largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width ca. 1xpd or slightly greater, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming moderately strong angle with one another. Venter: Mentum sparsely finely punctulate, shining; postmentum very finely densely micropunctulate, surrounding areas smooth, moderately shining. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/2/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides slightly converging toward blunt apex, apex raised slightly above mesoventral intercoxal process. Plaques moderately narrow posteriorly, tapering to point anteriorly, slightly converging toward one another anteriorly, weakly raised, located at sides of shallow median depression. AIS width at straight posterior margin ca. 2x P2. All tibiae slender, straight. Abdominal apex asymmetrical, with deep off-center notch.

Distribution. Currently known only from the type locality ( Fig. 41 ).

Etymology. Named in reference to the known distribution, and to the smile shaped pronotal fovea.

Figures

FIGURE 9. Hydraena camerojocula, 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 39–41. Geographical distributions of Cameroonian Hydraena.