Hydraena cameroconfinis, 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 : 19-20

Hydraena cameroconfinis , new species

Figs. 4 , 22 (habitus), 22 (aedeagus), 42 (map)

Type Material. Holotype (male): “ Cameroon: 35 km N. Ngaoundere, stream, 1.v.1982, P. D. Perkins collector” ( MCZ) . Paratypes: Same data as holotype (122 MCZ); 12 km. N. Ngaoundere, lake margin, 1.v.1982, leg. P. D. Perkins (1 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the comparatively large size (ca. 1.62 mm vs. 1.10–1.55 for other known species), the narrow metaventral plaques, and the aedeagus ( Fig. 9 ). The dorsal habitus is similar to that of H. camerocubita , but H. cameroconfinis is much larger (ca. 1.62 vs. 1.26 mm), and has different ventral proportions (P2/w/l/s ca. 1/0.25/1.5/1 vs. 1/0.15/0.15/2). The aedeagi of the two species are markedly dissimilar ( Figs. 15 , 22 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.62/0.68; head width 0.38; pronotum 0.39/0.52, PA 0.44, PB 0.45; elytra 0.94/0.68. Habitus as illustrated ( Fig. 22 ). Dorsum brown to light brown, head and pronotal macula darker, palpi light brown to testaceous, tip of last palpomere not darker. Dorsum of head and pronotum moderately densely punctulate, more sparsely punctulate on macula than on surrounding areas, interstices shining; punctures of frons disc and pronotal disc ca. 1xef, interstices ca. 2–3xpd or slightly larger; punctures of clypeus obsolete. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral, posterolateral, and posterosubmedial foveae very shallow.

Elytra with summit of posterior declivity slightly beyond midlength; lateral explanate margins narrow; 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 not forming angle with one another.

Venter: Mentum and postmentum nitid, dull. Genae very slightly raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.25/1.5/1. P1 laminate; median carina weakly sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt. Plaques narrow, straight, slightly converging toward one another 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 concave, width at straight posterior margin ca. 1x P2. Pro- and mesotibiae slender, straight. Metatibia slender, straight, inner margin with row of short setae. Abdominal apex with deep asymmetrical slightly off-center notch.

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

Etymology. Named in reference to the known distribution, near the northern limit of the Sudano-Guinean zone (zone 2), just south of the very dry Sudano-Sahelian zone (zone 1).

Figures

FIGURE 4. Dorsal habitus of Cameroonian species of Hydraena in Aedeagal Species Groups 3 and 4.

FIGURE 9. Hydraena camerojocula, new species, habitus and aedeagus of holotype.

FIGURE 15. Hydraena camerocubita, new species, habitus and aedeagus of holotype.

FIGURE 22. Hydraena cameroconfinis, new species, habitus and aedeagus of holotype.

FIGURES 42–43. Geographical distributions of Cameroonian Hydraena.