Hydraena cameroradiata, 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 : 29

Hydraena cameroradiata , new species

Figs. 5 , 37 (habitus), 37 (aedeagus), 41 (map)

Type Material. Holotype (male): “ Cameroon: C. S. Prov., Yaounde : Bastos, puddle, 12.xii.1981, leg. P. D. Perkins ” ( MCZ) . Paratypes: Same data as holotype (10 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the very sparcely and very finely punctulate head and pronotum, interstices strongly shining, the anterolateral pronotal foveae moderately deep, posterolateral and posterosubmedial foveae absent, the absence of metaventral plaques, and the aedeagus ( Fig. 37 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.33/0.59; head width 0.34; pronotum 0.35/0.47, PA 0.38, PB 0.43; elytra 0.80/0.59. Habitus as illustrated ( Fig. 37 ). Dorsum brown to light brown, frons and diffusely margined pronotal macula slightly darker, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum sparcely finely punctulate, pronotum more finely sparsely punctulate on macula than on surrounding areas, interstices shining; punctures of pronotal disc ca. 1xef, interstices ca. 3–5xpd or slightly larger; punctures of frons disc slightly larger and more closely spaced than those of pronotal disc; punctures of clypeus very fine, nearly obsolete. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral pronotal foveae moderately deep, posterolateral and posterosubmedial foveae absent.

Elytra with summit of posterior declivity at or very near midlength; lateral explanate margins narrow; punctures fine, on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior, each puncture with very short and very fine seta. Intervals not raised, width ca. 2–4xpd, as are interstices between punctures of a row. Apices in dorsal aspect separately rounded, in posterior aspect margins forming moderately strong angle with one another.

Venter: Mentum and postmentum sparsely finely punctulate, shining. Genae raised, shining, without posterior ridge. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques absent, median depression deep. AIS width at straight posterior margin ca. 2x P2. All tibiae slender. Pro- and mesotibiae very slightly arcuate, metatibia straight. Abdominal apex symmetrical, with shallow apicomedian notch.

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

Etymology. Named in reference to the known distribution, and to the highly reflective dorsum.

Figures

FIGURE 5. Dorsal habitus of Cameroonian species of Hydraena in Aedeagal Species Group 5.

FIGURE 37. Hydraena cameroradiata, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.