Hydraena camerodidacta, 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 : 27-28

Hydraena camerodidacta , new species

Figs. 5 , 34 (habitus), 34 (aedeagus), 40 (map)

Type Material. Holotype (male): “ Cameroon: N. W. Prov., 7 km. E. Bamenda, stream, 30.i.1982, leg. P. D. Perkins ” ( MCZ).

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the comparatively large body size (ca. 1.65 mm), the finely sparsely punctulate frons and pronotum, punctures very consistent in size throughout, interstices shining, the anterolateral foveae moderately deep, posterolateral and posterosubmedian foveae very shallow or absent, the very narrow plaques, with margins very ill-defined, and the aedeagus ( Fig. 34 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.65/0.69; head width 0.38; pronotum 0.38/0.53, PA 0.42, PB 0.48; elytra 0.98/0.69. Habitus as illustrated ( Fig. 34 ). Dorsum brown to dark brown, head, pronotal fascia and elytra dark brown, pronotum rather widely bordered anteriorly and posteriorly in light brown, maxillary palpi testaceous, tip of last palpomere not darker. Frons and pronotum finely sparsely punctulate, punctures of pronotum slightly larger than those of frons, very consistent in size throughout, interstices shining, ca. 1–3xpd. Clypeus medially very finely sparsely punctulate, shining; laterally densely micropunctulate, dull. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral foveae moderately deep, posterolateral and posterosubmedian foveae very shallow or absent.

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

Venter: Mentum very sparsely very finely punctulate, shining; postmentum very finely very densely micropunctulate, dull. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.3/1.3/1.3. P1 laminate; median carina sinuate in profile. P2 moderately wide, l/w ca. 2/1, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques very narrow, margins very ill-defined, slightly arcuate, slightly converging toward one another anteriorly, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 1x P2.All tibiae slender. Protibia and mesotibia very weakly arcuate. Metatibia straight. Abdominal apex symmetrical, with deep, narrow apicomedian notch.

Distribution. Currently known only from the type locality ( Fig. 40 ).

Etymology. Named in reference to the known distribution, and to the two finger-like processes of the aedeagus.

Figures

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

FIGURE 34. Hydraena camerodidacta, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.