Hydraena mahavavona, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 65-66

Hydraena mahavavona , new species

Figs. 54 (habitus), 56 (aedeagus), 253 (map)

Type Material. Holotype (male): Fianarantsoa, Ionilahy, Mahavavona , spring 1 Exp. NW (hygropetric), elev. 292 m, 21° 42' S, 47° 38' E, 20 iv 2011, R. Gerecke (MD 215) ( NMW).

Differential Diagnosis. Similar in dorsal habitus and shape of the metaventral plaques to H. simplicata ; differing therefrom in having less convex elytra, less ovate margins of the elytra, and color. The aedeagi of the two species differ markedly ( Figs. 51, 56).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.50/0.63; head width 0.38; pronotum 0.35/0.50, PA 0.43, PB 0.40; elytra 0.86/0.63.

Holotype slightly teneral, mature color most likely with dorsum reddish brown, head darker than pronotum, frons darker than clypeus; pronotum lighter than elytra; legs light brown to testaceous; maxillary palpi testaceous, distal ½ of last palpomere not darker.

Head with clypeus finely sparsely punctate medially, laterally very weakly microreticulate; frons more coarsely punctate laterally than medially where interstices ca. 1–3xpd. Pronotum in anterior and posterior 1/3 more densely punctate than on disc, interstices ca. 1xpd; punctures on disc distinctly smaller, interstices ca. 1–3xpd, shining. Mentum finely microreticulate, dull; postmentum finely microreticulate medially. Genae raised, shining, with posterior ridge, interrupted in midline.

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

Elytra weakly arcuate laterally; summit of posterior declivity at ca. midlength; lateral explanate margins moderately wide; serial punctures round, separated basally by ca. 1xpd, as large as largest pronotal punctures. Intervals not raised, shining, ca. 0.5–1xpd. 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. 1/0.5/2.5/1. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt and on same level as anteromedian carina of metaventrite. Plaques narrow, elongate, slightly converging anteriorly, separated basally by ca. 2x plaque width, located at sides of median depression. Metaventrite anteromedian carina ca. same length as plaques, attaining anterior level of plaques; long longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at arcuate posterior margin ca. 1.5x P2. Protibia straight, slender. Mesotibia slightly arcuate, medial margin with 4 or 5 short sharp spines, spines longer and stronger from most proximal to most distal, surface of tibia notched between spines. Metatibia straight, slender. Metafemur slender, arcuate on lateral margin, very weakly sinuate on medial margin. Abdominal apex with narrow apicomedian notch.

Etymology. Named in reference to the type locality.