Hydraena camerodigita, 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 : 28

Hydraena camerodigita , new species

Figs. 5 , 35 (habitus), 35 (aedeagus), 40, 42 (maps)

Type Material. Holotype (male): “ Cameroon: N. Prov., 35 km N. Ngaoundere, stream, 1.v.1982, leg. P. D. Perkins ” ( MCZ) . Paratypes: Same data as holotype (2 MCZ); N. W. Prov., Bamenda, stream nr. Skyline Hotel, 1.ii.1982, leg. P. D. Perkins (4 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the narrow P2 (l/w ca. 4/1), the very small, short and narrow plaques, the deep anterolateral pronotal foveae, and the aedeagus ( Fig. 35 ). Similar in habitus to H. camerosetosa , but differing therefrom in ventral and aedeagal characters.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.25/0.56; head width 0.34; pronotum 0.32/0.43, PA 0.37, PB 0.38; elytra 0.76/0.56. Habitus as illustrated ( Fig. 35 ). Dorsum brown to dark brown, frons and pronotal disc often darker, palpi testaceous, tip of last palpomere not darker. Dorsum of head and pronotum moderately finely and moderately sparsely punctulate, interstices shining; punctures of frons disc and pronotal disc ca. 1xef, interstices ca. 1–2xpd; clypeus dull, punctures very fine and dense. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral pronotal foveae deep, posterolateral and posterosubmedial pronotal foveae moderately deep

Elytra with posterior declivity very gradual, summit of at or very near midlength; lateral explanate margins moderately wide; on basal 1/3 punctures slightly larger than largest pronotal punctures, punctures becoming gradually smaller toward posterior, each puncture with very short and very fine seta. Intervals not raised, width ca. 1–2xpd or slightly greater, 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 very sparsely very finely punctulate, shining; postmentum very finely densely micropunctulate, moderately shining. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/ w/l/s) ca. 1/0.5/1/1.5. P1 laminate; median carina sinuate in profile. P2 l/w ca. 4/1, sides parallel, blunt apex raised slightly above mesoventral intercoxal process. Plaques very small, short, narrow, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 1.5x P2. All tibiae slender, straight. Abdominal apex symmetrical, with apicomedian notch.

Distribution. Currently known only from the type locality and a site at Bamenda ( Figs. 40 , 42 ).

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

Figures

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

FIGURE 35. Hydraena camerodigita, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.

FIGURES 42–43. Geographical distributions of Cameroonian Hydraena.