Hydraena cameroarida, 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 : 23-24

Hydraena cameroarida , new species

Figs. 5 , 28 (habitus), 28 (aedeagus), 39 (map)

Type Material. Holotype (male): “ Cameroon: N. Prov., 22 km. N. Maroua, desert stream, 14.i.1982, leg. P. D. Perkins ” ( MCZ).

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the brown to dark brown or black dorsum, the deep anterolateral pronotal foveae, and the aedeagus ( Fig. 28 ). Similar in habitus and size to H. camerocontinua , but differing therefrom in denser dorsal punctation, ventral morphology, and aedeagal characters.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.37/0.57; head width 0.34; pronotum 0.32/0.45, PA 0.38, PB 0.40; elytra 0.80/0.57. Habitus as illustrated ( Fig. 28 ). Dorsum brown to dark brown or black, frons and pronotal disc darker, maxillary palpi light brown, tip of last palpomere not darker. Frons finely moderately densely punctulate, ca. 1xef, interstices ca. 1–2xpd, interstices shining. Pronotum moderately coarsely moderately densely punctate, ca. 2xpd of frons punctures; interstices ca. 1xpd or slightly greater, shining. Clypeus medially very finely sparsely punctulate, shining; laterally very finely densely punctulate, dull. Labrum apicomedially excised, free margins not upturned. Pronotum with anterior margin weakly emarginate over middle 1/2; anterolateral pronotal foveae deep, posterolateral shallow, posterosubmedial moderately deep.

Elytra with summit of posterior declivity at or very near posterior 1/3; lateral explanate margins narrow; 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. 1–2xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rounded, in posterior aspect margins forming very weak angle with one another.

Venter: Mentum sparsely very finely punctulate, shining; postmentum very finely densely micropunctulate, dull. Genae raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.5/2/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt, apex raised slightly above mesoventral intercoxal process. Plaques narrow, straight or very slightly arcuate, not raised, located at sides of deep median depression. AIS width at straight posterior margin ca. 1.5x P2. Protibia very slender, straight. All tibiae slender, straight. Abdominal apex symmetrical, with deep apicomedian notch.

Distribution. Currently known only from the type locality ( Fig. 39 ).

Etymology. Named in reference to the known distribution, and to the arid area.

Figures

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

FIGURE 28. Hydraena cameroarida, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.