Hydraena bergsteni, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 41-43

Hydraena bergsteni , new species

Figs. 30 (habitus), 32 (aedeagus), 241 (map)

Type Material. Holotype (male): Antsiranana, Diana: Beraty: 2km East from Beraty village ; 14.02944S 48.27491E, big forest stream with big rocks, elev. 328 m, 22 xi 2012, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD12-22 ) ( NHRS) . Paratypes (3): Same data as holotype (2 NHRS); Mahajanga, Sofia: Maromiandra , forest stream, GB nets and sieves; stream with stones and gravels, S 14.02948 E 48.22443, elev. 173 m , 14° 2' S, 48° 13' E, 20 xi 2012, J. Bergsten, R. Bukontaite, J.H. Randriamihaja & T. Ranarilalatiana (Mad12-15) (1 NHRS).

Differential Diagnosis. Similar in color and size to H. oscillata , but having a differently shaped pronotum that is more transverse and with more distinctly bisinuate lateral margins; also, the elytra are less ovate and the pronotal punctures smaller. The aedeagi of the two species markedly differ ( Figs. 32 , 36).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.29/0.93; head width 0.55; pronotum 0.53/0.68, PA 0.55, PB 0.58; elytra 1.45/0.93.

Dorsum general coloration dark reddish brown; head darker than pronotum, almost piceous; pronotum narrowly bordered at anterior and posterior with light brown; elytra as dark as pronotal disc, except lighter humeral angles; legs brown to 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. 1–3xpd, each puncture with short distinctive seta. Pronotum densely coarsely punctate, interstices on disc ca. 0.5–1xpd, shining. Mentum moderately coarsely, sparsely punctate, interstices weakly shining; postmentum coarsely densely punctate. Genae raised, rugulose, with posterior ridge, interrupted in midline.

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

Elytra weakly arcuate laterally; summit of moderately steep posterior declivity at ca. midlength; lateral explanate margins wide; serial punctures large, round, separated by ca. 1xpd, slightly smaller than 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. 1/0.75/3/1. P1 as wide as P2; median carina markedly sinuate in profile. P2 l/w ca.2/1, sides parallel, apex blunt and on same level as anteromedian carina of metaventrite. Plaques roundly raised, converging very slightly, at anterior extreme becoming carinate lines and joining anteromedian carina; separated basally by slightly more than plaque width, located at sides of median depression. Metaventrite anteromedian carina shorter than plaques, as 1 to 2, joining carinae of plaques, together forming inverted 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. 1x P2. Protibia straight, slender. Mesotibia very slightly arcuate, middle 1/3 of medial margin with 5 or 6 short sharp spines, surface of tibia notched between spines. Metatibia straight, slender. Metafemur moderately slender. Abdominal apex arcuate.

Etymology. Named in honor of Johannes Bergsten, who has collected many new species of Malagasy Hydraenidae .

Figures

FIGURES 31 – 32. Hydraena, aedeagi of H. impressicollis (lectotype) and H. bergsteni (holotype).