Hydraena cameroclandestina, 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 : 13

Hydraena cameroclandestina , new species

Figs. 3 , 12 (habitus), 12 (aedeagus), 40 (map)

Type Material. Holotype (male): “ Cameroon: N. W. Prov., 7 km. E. Bamenda, stream, 30.i.1982, leg. P. D. Perkins ” ( MCZ) . Paratypes: Same data as holotype (5 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the moderately coarsely, very densely punctulate head and pronotum, and the aedeagus ( Fig. 12 ). The dorsal habitus is very similar to that of H. camerocrebrata and H. cameropetila ; all three species are in Aedeagal Species Group 2. H.cameroclandestina is larger in body size than H. cameropetila (ca. 1.32 vs. 1.20 mm); also, the P2 is wider than that of the two compared species. Reliable determinations of all three species will require examination of the male genitalia, which distinctly differ from one another.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.32/0.58; head width 0.33; pronotum 0.32/0.47, PA 0.38, PB 0.40; elytra 0.79/0.58. Habitus as illustrated ( Fig. 12 ). Dorsum dark brown to black, pronotum without macula, maxillary palpi brown. Dorsum of head and pronotum moderately coarsely, very densely punctulate, each puncture with short, distinctive whitish seta, interstices dull; punctures of frons disc and pronotal disc ca. 2xef, interstices ca. 1xpd or less; punctures of clypeus fine, dense. Labrum apicomedially excised, free margins rounded, weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral, posterolateral and posterosubmedial foveae shallow.

Elytra with summit of posterior declivity at about midlength; lateral explanate margins narrow to moderately wide; on basal 1/3 punctures ca. 2xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior, each puncture with short and fine conspicuous whitish seta. Intervals not raised, width ca. 0.5–1xpd, 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 very densely very finely punctulate, dull. 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, parallel, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 2x P2. All tibiae moderately stout. Protibia very slightly arcuate. Meso- and metatibiae straight. Abdominal apex symmetrical, with very small and shallow apicomedian notch.

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

Etymology. Named in reference to the known distribution, and to the close dorsal similarity to H. camerocrebrata n. sp. and H. cameropetila n. sp.

Figures

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

FIGURE 12. Hydraena cameroclandestina, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.