Hydraena levifurcata, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 89-90

Hydraena levifurcata , new species

Figs. 78 (habitus), 80 (aedeagus), 265 (map)

Type Material. Holotype (male): Fianarantsoa, Namorona River, 7 km SW Ranomafana, from stream with mossy rocks and sandy bottom, montane rainforest, elev. 1200 m, 21° 16' S, 47° 26' E, 23 x 1988, W. E. Steiner, C. Kremen, R. Van Epps ( USNM). Paratypes: Same data as holotype (4 USNM).

Differential Diagnosis. Differentiated from other members of the group by the comparatively smooth pronotal disc, which has punctures much smaller than the largest elytral punctures, the latter being random. The aedeagus has an unusually shaped distal piece with a sharply pointed process ( Fig. 80). Also see the diagnosis of H. inseriata .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.69/0.69; head width 0.39; pronotum 0.38/0.51, PA 0.41, PB 0.40; elytra 1.00/0.69.

Dorsum reddish brown, frons darker than clypeus and pronotum; legs brown to reddish brown; maxillary palpi light brown, 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. 2–4xpd. Pronotum in anterior and posterior 1/3 more densely punctate than on disc, interstices ca. 0.5–1xpd; punctures on disc distinctly smaller, interstices ca. 2–4xpd, shining. Mentum very finely sparsely punctate, shining; postmentum finely microreticulate medially. Genae raised, shining, with posterior ridge only laterally.

Pronotum arcuate laterally; anterior margin straight behind eyes, emarginate behind frons; PF1 shallow; PF2 very shallow, almost obsolete; PF3 deep; PF4 moderately deep; PF3 and PF4 shallowly confluent.

Elytra weakly arcuate laterally; summit of posterior declivity slightly before midlength; suture slightly peaked; lateral explanate margins wide; serial punctures round, separated basally by narrow walls to 1xpd, slightly larger than largest pronotal punctures, some basal punctures random or subserial. Intervals not raised, shining, ca. 0.5– 1xpd, very irregular where punctures random. 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. 1/0.3/2.5/1. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca. 3/1, sides slightly converging posteriorly, apex blunt and on same level as anteromedian carina of metaventrite. Plaques carinate or subcarinate, slightly converging anteriorly, separated basally by ca. 2– 3x 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, area between ridge and anteromedian carina concave. AIS width at arcuate posterior margin ca. 1.5x P2. Legs relatively long. Protibia straight or very slightly arcuate, slender. Mesotibia very slightly arcuate, medial margin with 3 or 4 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 relatively smooth dorsum and the inverted Y-shaped metaventral carinae.