Hydraena serripennis, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 24-25

Hydraena serripennis , new species

Figs. 14 (habitus), 17 (aedeagus), 234 (map)

Type Material. Holotype (male): Antsiranana, Forêt d' Antsahabe, 11.4 km 275° W Daraina, sifted litter (leaf mold, rotten wood) tropical dry forest, elev. 550 m, 13° 12' S, 49° 33' E, 12 xii 2003, B.L.Fisher (BLF 10116) ( CAS). Paratypes: Same data as holotype (1 CAS).

Differential Diagnosis. Very similar in size and dorsal habitus to H. rubridentata . Both species have deeply serrate elytral margins, deeper and more closely spaced than the serrations of H. parvipalpis ( Figs. 7 , 14, 15 ). Also, H. serripennis and H. rubridentata have much larger metaventral plaques than H. parvipalpis . The aedeagi of H. serripennis and H. rubridentata also clearly indicate a close relationship, but differ in shapes of the main piece and the rigid gonopore bearing distal tube ( Fig. 17, 18).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.77/0.85; head width 0.50; pronotum 0.38/0.68, PA 0.54, PB 0.57; elytra 1.10/0.85.

Dorsum dark brown, frons darkest; legs brown; maxillary palpi light brown to testaceous, distal ½ of last palpomere not darker.

Head and pronotum densely moderately coarsely punctate, frons punctures much larger in lateral concave area than on median relief, punctures of pronotum slightly larger than those of frons relief, each puncture with short recumbent seta; interstices varying from narrow ridges anteriorly and posteriorly to ca. 1xpd on disc, very weakly shining. Mentum sparsely finely punctulate and moderately setose, dull; postmentum rugulose, dull. Genae raised, weakly rugulose, dull, with posterior ridge, interrupted in midline.

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

Elytra arcuate near anterior angles and in posterior 0 25, ca. median 0.5 straight, parallel sided; summit of posterior declivity near midlength; lateral explanate margins very wide, widest at ca. posterior 0.75, margin very closely denticulate in anterior 0.75, widely and deeply serrate in posterior 0.25, row of punctures at base of explanate margin very large and very deep; serial punctures round, separated by ca. 1xpd, distinctly smaller than largest pronotal punctures. Even numbered intervals 2–10 weakly raised and granulate. Odd numbered intervals flat, ca. 2xpd, shining. Apices in dorsal aspect separately weakly rounded, in posterior aspect margins do not form angle with one another.

P1 and P2 narrow, subequal in width. P1 median carina very weakly sinuate, almost arcuate, in profile. P2 with sides parallel, apex rounded. Plaques moderately large, very sparsely and very finely punctate, parallel, narrowly confluent anteriorly, located at posterior sides of rather shallow 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. 2x P2. Legs short, stout. Male fifth abdominal ventrite very weakly, if at all, transversely raised. Abdominal apex with large apicomedian notch.

Etymology. Named in reference to the deeply serrate elytral margins.

Figures

FIGURE 7. Hydraena parvipalpis, holotype, habitus dorsal, lateral, and ventral.

FIGURE 15. Hydraena rubridentata, holotype, habitus dorsal, lateral, and ventral.

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