Hydraena camerocordata, 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 : 26-27

Hydraena camerocordata , new species

Figs. 5 , 33 (habitus), 33 (aedeagus), 41 (map)

Type Material. Holotype (male): “ Cameroon: C. S. Prov., Etoug Ebe , stream with dead leaves, 22.iv.1982, leg. P. D. Perkins ” ( MCZ) . Paratypes: Same data as holotype (2 MCZ) .

Differential Diagnosis. Differentiated from other members of the genus in Cameroon by the combination of the large body size (ca. 1.53 mm), the markedly cordiform pronotum, the very wide P1 and P2, and the aedeagus ( Fig. 33 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.53/0.69; head width 0.36; pronotum 0.38/0.52, PA 0.41, PB 0.38; elytra 0.90/0.69. Habitus as illustrated ( Fig. 33 ). Pronotum markedly cordiform, width at midlength much wider than anterior and posterior margins. Dorsum dark brown to black, except labrum, clypeus, and maxillary palpi light brown to testaceous, tip of last palpomere not darker. Frons moderately finely moderately sparsely punctate, punctures ca. 1xef. Pronotum coarsely densely punctate, especially anterior and posterior to moderately convex disc, interstices in densely punctate areas narrow walls; interstices on disc ca. 1xpd, shining; punctures laterally much smaller and sparser. Punctures of clypeus very fine, moderately dense on disc, very dense laterally. Labrum apicomedian excision deep and wide, free margins weakly upturned, angulate laterally and medially. Pronotum anterior margin weakly emarginate over middle 1/2; antero- and posterolateral pronotal foveae deep, shallowly confluent; posterosubmedial foveae deep, area between antero- and posterolateral foveae distinctly convex.

Elytra with posterior declivity rather abrupt, summit at or very near midlength; lateral explanate margins wide; on basal 1/3 punctures 1xpd or slightly larger and deeper than largest pronotal punctures, punctures becoming gradually slightly smaller laterally and toward posterior. Intervals not raised, width on disc ca. 1xpd, much wider laterally and posteriorly, interstices between punctures of a row ca. 1–6xpd, each puncture with very short and very fine seta. Apices in dorsal aspect conjointly rather sharply rounded, in posterior aspect margins forming shallow angle with one another.

Venter: Mentum finely sparsely punctulate, shining. Postmentum densely micropunctulate, dull. Genae very slightly raised, shining, without posterior ridge. Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.1/0.2/1.5. P1 and P2 very wide. P2 l/w ca. 1/1, sides parallel, apex blunt. Plaques very small, very short, widely separated carinate lines, located at sides of deep median depression. AIS very wide, weakly concave, width at straight posterior margin ca. 1.2x P2. Tibiae slender, straight. Protibia very slightly widened and bearing short spine at ca. distal 2/3. Mesotibia slightly widened at ca. distal 2/3. Abdominal apex symmetrical, with rather wide and deep apicomedian notch.

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

Etymology. Named in reference to the known distribution, and to the markedly cordiform pronotum.

Figures

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

FIGURE 33. Hydraena camerocordata, new species, habitus and aedeagus of holotype.

FIGURES 39–41. Geographical distributions of Cameroonian Hydraena.