Hydraena parvipalpis, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 17-19

Hydraena parvipalpis , new species

Figs. 7 (habitus), 11 (aedeagus), 231, (antenna, maxillary palpus, gonocoxite and spermatheca), 234 (map)

Type Material. Holotype (male): Antananarivo, Réserve Spéciale d'Ambohitantely, Forêt d Ambohitantely , 20.9 km 72° NE d’ Ankazobe, sifted litter in montane rainforest, elev. 1410 m, 18° 13' S, 47° 17' E, 17–22 iv 2001, Fisher, Griswold, et al. (BLF 3694) ( CAS) . Paratypes ( 733 ): Same data as holotype (709); Antananarivo, Ambohitantely Spec. Res., forest edge; sifting forest litter , Winkler app. extr., elev. 1533 m, 18° 11' S, 47° 17' E, 19 iv 2011, P. Banar & R. Raveloson ( ABT /08/2011) (16 MMBC); Ambohitantely Spec. Res ., sifting litter = plant residues under Pandanus; Winkler app. extr., elev. 1609 m, 18° 11' S, 47° 17' E, 20 iv 2011, L.S. Rahanitriniaina, R. Raveloson ( ABT /19/2011) (8 MMBC).

Differential Diagnosis. Recognized by the combination of the deep and widely separated serrations of the elytral margin, and the very small, almost absent, metaventral plaques at the posterior margin of the deep median depression. The aedeagus differs from all others in this group by the shapes of the distal part of the main piece and the distal piece itself, both of which are wide in lateral view ( Fig. 11). Males have the fifth abdominal ventrite more distinctly transversely raised than other members of the group.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.73/0.83; head width 0.46; pronotum 0.39/0.64, PA 0.50, PB 0.56; elytra 1.12/0.83.

Dorsum dark brown, frons darkest; legs brown; maxillary palpi brown to light brown, 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 narrow ridges 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; anterior margin distinctly emarginate behind eyes, very weakly emarginate behind frons; PF1 and PF2 shallow; PF3 and PF4 deep, area between them tumid.

Elytra arcuate laterally; summit of posterior declivity near midlength; lateral explanate margins very wide, margin serrate, very closely so 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 slightly rectangular, each with minute granule at anterior margin, separated by ca. 1xpd, slightly 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 sinuate in profile. P2 with sides converging to pointed apex. Plaques very small, almost absent, located at posterior sides of deep median depression, latter very slightly peaked at apicomedian margin. 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 transversely raised. Abdominal apex with large apicomedian notch.

Etymology. Named in reference to the very short maxillary palpi.

Remarks. The large elytral serrations are present only in males; the serrations are much smaller in females.

Figures

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