Hydraena lubrica, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 52-53

Hydraena lubrica , new species

Figs. 41 (habitus), 43 (aedeagus), 246 (map)

Type Material. Holotype (male): Antananarivo, Ambohitantely Spec. Res ., sifting forest litter, Winkler app. extr., elev. 1593 m, 18° 10' S, 47° 17' E, 19 iv 2011, L.S. Rahanitriniaina, P. Banar, R. Raveloson ( ABT/01/2011 ) ( MMBC). Paratypes: Same data as holotype (5 MMBC).

Differential Diagnosis. Differentiated from other members of the species group by the very large metaventral plaques, each plaque being long and ca. twice as wide as the interplaque area. The aedeagus bears some general resemblance to that of H. antsahabe , but the shapes of the main piece and distal piece, especially in ventral view, clearly differ; also, H. lubrica body size is larger (ca. 1.51 vs. 1.37 mm).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.51/0.64; head width 0.38; pronotum 0.34/0.50, PA 0.41, PB 0.42; elytra 0.91/0.64.

Dorsum dark brown, head darkest, almost piceous; legs brown; maxillary palpi brown to light brown, distal ½ of last palpomere not darker.

Head with clypeus finely sparsely punctate and microreticulate, dull; frons punctures much larger, interstices 0.5–3xpd, shining. Pronotum moderately densely moderately coarsely punctate, punctures in anterior and posterior 1/3 larger than those of head; interstices narrow walls to 0.5xpd; disc punctures finer and sparser, interstices ca. 1– 3xpd, shining. Mentum sparsely finely punctulate, microreticulate, dull; postmentum microreticulate in shallow median depression, dull. Genae raised, shining, with posterior ridge, interrupted in middle.

Pronotum arcuate laterally; anterior margin straight behind eyes, emarginate behind frons; PF1, PF2 and PF4 absent; PF3 shallow.

Elytra weakly arcuate laterally; summit of posterior declivity near midlength; lateral explanate margins moderately narrow; serial punctures slightly rectangular, each with minute granule at anterior margin, ca. 1xpd. Intervals not raised, weakly shining, ca. 1xpd. Apices in dorsal aspect conjointly rather sharply rounded, in posterior aspect margins not forming angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1.5/3/0.75. P1 almost as wide as P2; median carina weakly sinuate in profile. P2 l/w ca. 2/1, sides slightly converging to blunt apex, apex at same level as anteromedian carina of metaventrite. Plaques very large, oval, parallel, narrowly separated, slightly raised, located at sides of narrow median depression. Metaventrite anteromedian carina slightly shorter than plaques, extending posteriorly to between anterior extreme of plaques; long longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity to ca. midlength of metaventrite. AIS width at slightly arcuate posterior margin ca. 2x P2. Protibia straight, moderately wide. Mesotibia straight, stout, widest near midlength, 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, most distal notch deepest. Metatibia straight. Metafemur lateral margin strongly arcuate, medial margin weakly bisinuate. Abdominal apex with small apicomedian notch.

Etymology. Named in reference to the large, smooth metaventral plaques.

Figures

FIGURE 41. Hydraena lubrica, holotype, habitus dorsal, lateral, and ventral.