Hydraena ravoandrina, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 105-106

Hydraena ravoandrina , new species

Figs. 94 (habitus), 96 (aedeagus), 273 (map)

Type Material. Holotype (male): Antananarivo, Anjozorobe, Ravoandrina , small str. at campsite, near forest border, elev. 1280 m, 18° 13' S, 47° 31' E, 18 vii 2001, Gerecke & Goldschmidt (MD 9) ( NMW) . Paratypes (20): Same data as holotype (13 NMW); Antananarivo, Anjozorobe (Antananarivo), Ravoandrina , Riv. Ampanakamonty near campsite, elev. 1280 m, 18° 13' S, 47° 31' E, 21 vii 2001, Gerecke & Goldschmidt (MD 11d) (1 NMW); Anjozorobe (Antananarivo), Ravoandrina , Riv. Ampanakamonty near campsite, lower course forest, elev. 1280 m, 18° 13' S, 47° 31' E, 21 vii 2001, Gerecke & Goldschmidt (MD 11b) (2 NMW); Anjozorobe (Antananarivo), Ravoandrina , Riv. Ampanakamonty near campsite, elev. 1280 m, 18° 13' S, 47° 31' E, 21 vii 2001, Gerecke & Goldschmidt (MD 11c) (4 NMW).

Differential Diagnosis. Very similar in habitus to H. gereckei and H. manjakatompo ; differing therefrom by the smaller size (ca. 2.03 vs. 2.20 mm), the proportionally larger pronotum, and, in males, the straight metatibiae. The aedeagus of H ravoandrina also indicates a relationship with the compared species, but differs in the shape of the distal part of the main piece and especially the shape of the distal piece.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.03/0.91; head width 0.47; pronotum 0.43/0.71, PA 0.53, PB 0.60; elytra 1.33/0.91.

Dorsum dark reddish brown, head darker than pronotum and elytra; elytral epipleurs lighter than remainder of elytra, and lighter than venter; legs brown to reddish brown; maxillary palpi testaceous, distal ½ of last palpomere not darker.

Head moderately finely and moderately densely punctate; frons more coarsely punctate laterally than medially where interstices ca. 0.5–1xpd. Pronotum in anterior and posterior 1/3 coarsely densely punctate, interstices narrow walls or less than 1xpd; punctures on disc distinctly smaller, interstices ca. 1–2xpd, shining. Mentum microreticulate, dull; postmentum microreticulate medially. Genae raised, shining, with posterior ridge, interrupted in midline.

Pronotum arcuate laterally; anterior margin straight behind eyes, emarginate behind frons; PF1 very shallow, margins ill-defined; PF2 absent; PF3 deep; PF4 moderately deep.

Elytra weakly arcuate laterally; summit of posterior declivity slightly before midlength; lateral explanate margins wide; serial punctures slightly rectangular, each with minute granule at anterior margin, separated by ca. 1xpd, slightly smaller than largest pronotal punctures. Intervals not raised, shining, ca. 1x puncture width. Apices in dorsal aspect rather sharply conjointly rounded, in posterior aspect margins forming very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/1/3/2. P1 slightly narrower than P2; median carina weakly sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt and on same level as anteromedian carina of metaventrite. Plaques subtriangular, narrowing and slightly converging anteriorly, separated basally by ca. 2x plaque width, very slightly raised, located at sides of median depression. Metaventrite anteromedian carina ca. as long as plaques, not quite attaining anterior level of plaques; long longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at arcuate posterior margin ca. 2x P2. Protibia medial margin straight, lateral margin very weakly arcuate. Mesotibia arcuate, widest near midlength, medial margin with 4 or 5 short sharp spines, surface of tibia notched between spines, spines longer and stronger from most proximal to most distal. Metatibia straight, medial margin slightly emarginate in distal 0.5, slender. Metafemur strongly arcuate lateral margin, medial margin weakly sinuate. Abdominal apex with narrow apicomedian notch.

Etymology. Named in reference to the geographical distribution.

Figures

FIGURE 94. Hydraena ravoandrina, holotype, habitus dorsal, lateral, and ventral.