Hydraena sculponea, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 94-95

Hydraena sculponea , new species

Figs. 82 (habitus), 84 (aedeagus), 267 (map)

Type Material. Holotype (male): Antsiranana, Befingotra (9.2 km WSW), Res. Anjanaharibe-Sud, montane rainforest, sifted litter (leaf mold, rotten wood), elev. 1280 m, 14° 45' S, 49° 28' E, 5 xi 1994, B. L. Fisher (#1158) ( FMNH). Paratypes: Same data as holotype (3 FMNH).

Differential Diagnosis. Similar to H. jubata in general habitus, size, and the possession of arcuate metatibiae; distinguished therefrom by the differently shaped metaventral plaques, which are flat and each wider than the intervening space in H. sculponea , and the brownish instead of reddish brown color. The aedeagi of the two species are markedly dissimilar ( Figs. 83, 84).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.02/0.87; head width 0.48; pronotum 0.46/0.67, PA 0.48, PB 0.52; elytra 1.33/0.87.

Dorsum general coloration dark brown; head and pronotal disc darker, almost piceous; anterior border of pronotum very slightly lighter; legs dark brown; maxillary palpi light brown, distal ½ of last palpomere not darker.

Head with clypeus finely moderately densely punctate; frons slightly more coarsely punctate laterally than medially where interstices ca. 1–2xpd, each puncture with short distinctive seta. Pronotum in anterior and posterior 1/3 slightly more densely punctate than on disc, interstices ca. 1xpd; punctures on disc smaller, interstices ca. 1– 1.5xpd, shining. Mentum coarsely punctate, interstice very weakly shining; postmentum finely densely punctate. Genae rugulose with posterior ridge, interrupted in midline; laterally grooved to receive maxillary palpus.

Pronotum subcordiform; anterior margin straight behind eyes, emarginate behind frons; PF1 and PF2 absent; PF3 moderately deep; PF4 shallow; PF3 and PF4 very shallowly confluent.

Elytra weakly arcuate laterally; summit of moderately steep posterior declivity at ca. midlength; lateral explanate margins wide; serial punctures small, round, separated by ca. 1xpd or less, slightly smaller than largest pronotal punctures. Intervals ca. 1xpd, 2, 4, 6, and 8 weakly raised, shining. Apices in dorsal aspect rather sharply conjointly rounded, in posterior aspect margins not forming angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/2/6/0.5. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca.3/1, sides converging slightly, apex blunt and on same level as anteromedian carina of metaventrite. Plaques large, raised, flat, oval, converging slightly anteriorly, becoming short carinate lines where joining anteromedian carina, separated basally by slightly less than plaque width, located at sides of median depression. Metaventrite anteromedian carina shorter than plaques, lengths as 1 to 2, joining anterior carinate lines of plaques, together forming inverted semi-Y-shape; long and strong, slightly arcuate longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at arcuate posterior margin ca. 2x P2. Protibia very slightly arcuate. Mesotibia straight, subapically medial margin notched. Metatibia moderately arcuate, slender. Metafemur moderately slender. Abdominal apex with small apicomedian notch.

Etymology. "Wooden shoe"; named in reference to the shape of the large paramere.