Hydraena rubridentata Perkins 2017, new species

Hydraena rubridentata, new species

Figs. 15 (habitus), 18 (aedeagus), 234 (map)

Type Material. Holotype (male): Mahajanga, Parc National de Namoroka, 16.9 km 317° NW Vilanandro, sifted litter (leaf mold, rotten wood), tropical dry forest, elev. 100 m, 16° 24' S, 45° 18' E, 12–16 xi 2002, Fisher, Griswold et al. (BLF 6582) CAS). Paratypes: Same data as holotype (2 CAS).

Differential Diagnosis. Very similar in habitus to H. serripennis, although more reddish in color and with slight punctation differences; reliable determinations will require examination of the male genitalia. Refer to the diagnosis of H. serripennis.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.77/0.80; head width 0.48; pronotum 0.39/0.67, PA 0.57, PB 0.53; elytra 1.14/0.80.

Dorsum brown to 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. Punctures of pronotum larger than those of head, each puncture with short recumbent seta; interstices varying from ca. 0.5xpd anteriorly and posteriorly to ca. 1xpd on disc, very weakly shining. Mentum sparsely finely punctulate and moderately setose, weakly shining; postmentum rugulose, dull. Genae raised, weakly rugulose, dull, with posterior ridge, interrupted in midline.

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

Elytra arcuate laterally; summit of posterior declivity near midlength; lateral explanate margins very wide, margin minutely denticulate in anterior 0.5, widely and moderately deeply 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. 1xpd, slightly smaller than largest pronotal punctures. Even numbered intervals 2–10 granulate, intervals 2–6 very weakly raised, intervals 8 and 10 slightly higher. 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 narrow, subequal in width. P1 median carina very weakly sinuate in profile. P2 with sides converging to pointed apex. Plaques moderately large, very slightly convergent anteriorly, almost parallel, minutely punctate, located at sides of deep 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. 4x P2. Legs short, stout. Male fifth abdominal ventrite transversely raised. Abdominal apex with large apicomedian notch.

Etymology. Named in reference to the reddish color and markedly serrate elytral margins.