Hydraena contorta, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 134-136

Hydraena contorta , new species

Figs. 120 (habitus), 122 (aedeagus), 286 (map)

Type Material. Holotype (male): Antananarivo, 18.4133S 47.9443E Analamanga, 10km E of Anjozorobe, Anjozorobe forest reserve, forest stream next to Saha forest camp, elev. 1240 m, 23 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren ( MAD14-77 ) ( NHRS) . Paratypes (14): Same data as holotype (10 NHRS). Antananarivo, 18.4128S 47.9439E Analamanga Anjozorobe forest reserve Marsh next to stream, by Saha forest , 10km E of Anjozorobe, forest marsh, elev. 1320 m, 18° 24' S, 47° 56' E, 23 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren ( MAD14-78 ) (4 NHRS).

Differential Diagnosis. Somewhat similar to H. torquata in shape, dorsal punctation, and deep pronotal foveae PF2; externally differing therefrom in size (ca. 1.69 vs. 1.39 mm), color (reddish brown with a distinct pronotal macula), having a slightly differently shaped pronotum, and larger metaventral plaques. The aedeagi of the two species are similar in being twisted such that the very large left paramere wraps around the dorsal side of the aedeagus, the right paramere is small and located on the left side; also, the main piece has a prominent lobe near midlength. Otherwise, the shapes of the two aedeagi differ markedly ( Figs. 121, 122).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.69/0.74; head width 0.42; pronotum 0.40/0.58, PA 0.46, PB 0.52; elytra 1.10/0.74.

Dorsum of head with frons and clypeus dark brown to piceous; pronotum with dark brown macula, diffusely margined, borders light brown to testaceous, lighter anteriorly; elytra brown; legs light brown; maxillary palpi palpi testaceous, distal ½ of last palpomere not darker.

Frons punctures ca. 2xef; interstices effacedly microreticulate, dull, 0.5–1xpd laterally, 1–2xpd medially.

Clypeus very finely sparsely punctate, effacedly microreticulate, dull. Mentum sparsely finely punctulate, shining; postmentum sparsely punctulate and very effacedly microreticulate, shining. Genae raised, smooth, shining, without posterior ridge.

Pronotum with lateral margins slightly sinuate, posterior angles nearly right angles; anterior margin straight behind eyes, emarginate in middle; punctures on disc much larger and deeper than those of frons, interstices weakly shining, 1–2xpd, punctures slightly denser at anterior and posterior; PF1 absent; PF2 shallow, oval; PF3 deep and large; PF4 moderately deep; PF3 and PF4 confluent.

Elytra weakly arcuate laterally; posterior declivity slightly before midlength; lateral explanate margins moderately wide; serial punctures on disc ca. 1xpd largest pronotal punctures. Intervals not raised, weakly shining, ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly truncately rounded, in posterior aspect margins forming deep angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/3/2. P1 laminate; median carina sinuate in profile. P2 narrow, l/w ca. 2/1, sides parallel or slightly converging, blunt apex raised slightly above mesoventral intercoxal process. Plaques narrow, elongate, margins indistinct, not raised, located at sides of shallow median depression.

AIS width at slightly arcuate posterior margin ca. 2x P2. Pro- and mesotibia very slightly arcuate. Metatibia straight , slender. Abdominal apex with apicomedian notch.

Etymology. Named in reference to the twisted, intricate and complex aedeagus.