Hydraena parvispinosa, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 76-77

Hydraena parvispinosa , new species

Figs. 65 (habitus), 67 (aedeagus), 258 (map)

Type Material. Holotype (male): Toamasina, Andasibe NP, elev. 980 m, 18° 46' S, 48° 24' E, 10–11 xii 2004, Balke, Monaghan et al. (MD37/MD34) ( NHRS) . Paratypes (11): Same data as holotype (1 NHRS); Toamasina, Alaotra Mangoro: Analamazoatra SR: S border of reserve E Antsapanana: S 18.95371 E 0 48.42859, GB Nets and sieves, small stream, elev. 910 m, 18° 57' S, 48° 26' E, 9 xi 2011, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD11-28 ) (1 NHRS); Alaotra Mangoro: Analamazoatra SR: S of Andasibe village : S 18.93149 E 0 48.42916, GB Nets and sieves, forest stream below dam, elev. 1070 m, 18° 55' S, 48° 26' E, 8 xi 2011, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD11-24 ) (1 NHRS); Mantadia N.P., "Sacred Cascade " 18° 49.784' S, 48° 25.917' E, rockpools at side of cascade, elev. 948 m, 18° 50' S, 48° 26' E, 14 xi 2014, P. D. Perkins (8 MCZ).

Differential Diagnosis. The males of H. parvispinosa can be differentiated from other males in the group by the comparatively small mesotibial spines. This is a rather broad, darkly colored species that has wide intercoxal processes and strong metaventral carinae. The aedeagus, which is diagnostic, has a very long coiled flagellum that, when unwound, is ca. 8–10 times the length of the main piece.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.89/0.87; head width 0.51; pronotum 0.48/0.63, PA 0.53, PB 0.53; elytra 1.13/0.87.

Dorsum with head dark brown to piceous, remainder of dorsum reddish brown; legs light brown to testaceous; maxillary palpi testaceous, distal ½ of last palpomere not darker.

Head with clypeus moderately finely and moderately densely punctate; frons moderately coarsely and moderately densely punctate, interstices 0.5–2xpd, shining. Pronotum coarsely densely and deeply punctate, interstices narrow walls or less than 1xpd, shining. Mentum sparsely, moderately coarsely punctate, interstices shining; postmentum subscabrous in median depression, surrounding area shining. Genae raised, shining, with posterior ridge, interrupted in midline.

Pronotum distinctly sinuate laterally; anterior margin straight behind eyes, emarginate behind frons; PF1 and PF2 absent; PF3 and PF4 deep, confluent.

Elytra weakly arcuate laterally; summit of posterior declivity near midlength; lateral explanate margins moderately wide; serial punctures round, separated by ca. 1xpd or slightly less, slightly smaller than largest pronotal punctures. Intervals very weakly if at all raised, shining, ca. 1xpd. Apices in dorsal aspect conjointly rounded, in posterior aspect margins do not form angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.25/2/1. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca. 1.5/1, sides converging slightly posteriorly, apex blunt and on same level as anteromedian carina of metaventrite. Plaques carinate, converging anteriorly and almost but not quite joining anteromedian carina; plaques separated basally by ca. 4x plaque width, located at sides of deep median depression. Metaventrite anteromedian carina ca. same length as plaques; long longitudinal and slightly arcuate ridge on each side, extended posteriorly from margin of each mesocoxal cavity, almost attaining metacoxal cavity. Metaventrite concave at anterolateral angles. AIS width at arcuate posterior margin ca. 1x P2. All tibiae straight, slender. Mesotibia with 4–5 very short spines subapically on median margin, margin not notched between spines. Metafemur slender, arcuate on lateral margin, very weakly sinuate on medial margin. Abdominal apex without apicomedian notch.

Etymology. Named in reference to the relatively small spines of the male mesotibiae.