Hydraena camerocubita, 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

Hydraena camerocubita , new species

Figs. 3 , 15 (habitus), 15 (aedeagus), 42 (map)

Type Material. Holotype (male): “ Cameroon: 35 km N. Ngaoundere, stream, 1.v.1982, P. D. Perkins collector” ( MCZ) . Paratypes: 12 km. N. Ngaoundere, lake margin, 1.v.1982, P. D. Perkins collector (2 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the small size (ca. 1.26 mm), the metaventral plaques that are very small, very narrow, subcarinate lines, and the aedeagus ( Fig. 15 ). The dorsal habitus is similar to that of H. cameroconfinis n. sp., but the present species is much smaller (ca. 1.26 vs. 1.66 mm), and has different ventral proportions (P2/w/l/s ca. 1/0.15/0.15/2 vs. 1/0.25/1.5/1). The aedeagi of the two species are markedly dissimilar.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.26/0.52; head width 0.33; pronotum 0.30/0.41, PA 0.33, PB 0.37; elytra 0.76/0.52. Habitus as illustrated ( Fig. 15 ). Dorsum brown to light brown, head and pronotal macula dark brown to black, 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 slightly smaller than 1xef, on pronotal disc slightly larger than 1xef, interstices ca. 2–3xpd or slightly larger; punctures of clypeus obsolete. Labrum apicomedially excised. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral foveae moderately deep, posterolateral pronotal foveae very shallow, posterosubmedial foveae very shallow.

Elytra with summit of posterior declivity slightly beyond midlength; lateral explanate margins narrow; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width ca. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect slightly separately rounded, in posterior aspect margins forming very shallow angle with one another.

Venter: Mentum and postmentum densely micropunctulate, dull. Genae very slightly raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.15/0.15/2. P1 laminate; median carina weakly sinuate in profile. P2 l/w ca. 2.5/1, sides almost parallel, apex blunt. Plaques very small, very narrow, subcarinate lines, straight, convergent anteriorly, very weakly if at all raised, 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 weakly concave, width at straight posterior margin ca. 2x P2. Pro-, meso- and metatibiae slender, straight. Abdominal apex symmetrical, with apicomedian notch.

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

Etymology. Named in reference to the known distribution and the arm-like shape of the gonopore bearing process of the aedeagus.

Figures

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

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

FIGURES 42–43. Geographical distributions of Cameroonian Hydraena.