Hydraena genuvela, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 21-24

Hydraena genuvela , new species

Figs. 9 (habitus), 13 (aedeagus), 234 (map)

Type Material. Holotype (male): Antsiranana, Forêt de Binara, 9.1 km 233° SW Daraina, sifted litter (leaf mold, rotten wood) rainforest, elev. 650–800 m, 13° 15' S, 49° 36' E, 3 xii 2003, B.L.Fisher (BLF 9656) ( CAS). Paratypes: Same data as holotype (2 CAS).

Differential Diagnosis. Very similar in size, habitus and plaques to H. fortipes . Differing therefrom in the slightly more coarsely and more densely punctate dorsum. Reliable determinations will require examining the aedeagi, which differ in shapes of the main piece and the rigid gonopore bearing distal tube ( Figs. 12, 13).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.80/0.87; head width 0.49; pronotum 0.37/0.71, PA 0.59, PB 0.58; elytra 1.16/0.87.

Dorsum dark brown, frons darkest; legs (except coxae), pronotal hypomeron, and elytral epipleura light brown; venter and coxae dark brown; maxillary palpi light brown to testaceous, distal ½ of last palpomere not darker.

Frons and pronotum densely moderately coarsely punctate, clypeus much more finely and sparsely punctate than frons. Punctures of pronotum larger than those of head, each puncture with short recumbent seta; interstices varying from narrow ridges to ca. 0.5xpd, some punctures on disc confluent, interstices very weakly shining.

Mentum sparsely finely punctulate and moderately setose, dull; postmentum subrugulose, dull. Genae raised, weakly rugulose, dull, with posterior ridge, interrupted in midline.

Pronotum widely arcuate laterally, slightly sinuate behind middle; anterior margin distinctly emarginate behind eyes, very weakly emarginate behind frons; PF1 and PF2 shallow; PF3 and PF4 deep, area between them weakly tumid.

Elytra arcuate laterally; summit of posterior declivity slightly before midlength; lateral explanate margins very wide, margin serrate, distance between serrations in posterior 0.5 ca. 2– 3x those in anterior 0.5, widely serrate in posterior 0.5, row of punctures at base of explanate margin very large and very deep; serial punctures round, each with minute granule at anterior margin, separated by ca. 0.5–1xpd, slightly larger than largest pronotal punctures. Even numbered intervals 2–10 raised and granulate. Sutural interval slightly peaked over posterior declivity. Odd numbered intervals flat, ca. 1xpd, shining. Apices in dorsal aspect separately weakly rounded, in posterior aspect margins do not form angle with one another.

P1 and P2 very narrow, P1 slightly wider than P2. P1 median carina sinuate in profile. P2 almost parallel sided, apex pointed. Plaques very small, surface irregular, located at posterior sides of median depression. Metaventrite with very short point on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at slightly arcuate posterior margin ca. 5x P2. Legs short, stout. Male fifth abdominal ventrite with transversely raised glabrous ridge. Abdominal apex with large apicomedian notch.

Etymology. Named in reference to the large explanate margins of the elytra, which form shields over the "knees" of the middle and hind legs.

Figures

FIGURES 233 – 236. All locality sites for Hydraena, Hydraena (Micromadraena), Limnebius, and Madagaster.