Hydraena ranomafana, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264: 64-65

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Hydraena ranomafana

new species

Hydraena ranomafana   , new species

Figs. 53 (habitus), 55 (aedeagus), 252 (map)

Type Material. Holotype (male): Fianarantsoa, Ranomafana, Sahamalaotra , elev. 1123 m, 21° 16' S, 47° 25' E, 1 xi–30 xii 2004, M. Balke (MD 031) ( ZSMC). GoogleMaps  

Differential Diagnosis. Similar to H. multiarcuata   in having arcuate meso- and metatibiae, but the arcuations are much less than the compared species, and the habitus, color and size of the two species differ markedly. The aedeagus perhaps has some very superficial resemblance to that of H. multiarcuata   , but differs in many respects of both distal piece and main piece, and size ( Figs. 52, 55).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.74/0.73; head width 0.39; pronotum 0.41/0.56, PA 0.44, PB 0.43; elytra 1.07/0.73.

Holotype slightly teneral, mature color most likely with dorsum reddish brown, head darker than pronotum, frons darker than clypeus; pronotum lighter than elytra; legs light brown to testaceous; maxillary palpi testaceous, distal ½ of last palpomere not darker.

Labrum anterolateral corners angulate, anterior margin of each lobe emarginate. Head with clypeus finely sparsely punctate medially, laterally very weakly microreticulate; frons more coarsely punctate laterally than medially where interstices ca. 2–3xpd. Pronotum in anterior and posterior 1/3 more densely punctate than on disc, interstices ca. 0.5–1xpd; punctures on disc distinctly smaller, interstices ca. 2–3xpd, shining. Mentum finely microreticulate, dull; postmentum finely microreticulate medially. Genae raised, shining, with posterior ridge, interrupted in midline.

Pronotum bisinuate laterally; anterior margin straight behind eyes, emarginate behind frons; PF1 and PF2 very shallow, almost obsolete; PF3 and PF4 deep and very shallowly confluent.

Elytra weakly arcuate laterally; summit of steep posterior declivity slightly before midlength; suture slightly peaked in ca. middle 1/3; lateral explanate margins wide; serial punctures round, large and deeply impressed on basal 0.5, becoming very fine over posterior declivity, separated basally by ca. 1xpd, larger than largest pronotal punctures, punctures of series beyond the fifth becoming random. 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. 1/0.5/2/3. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca. 2/1, sides parallel, apex blunt and on same level as anteromedian carina of metaventrite. Plaques narrow, subcarinate, arcuate and slightly converging anteriorly, separated basally by ca. 2– 3x plaque width, located at sides of median depression. Metaventrite anteromedian carina ca. same length as plaques, 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 straight, slender. Mesotibia slightly arcuate, medial margin with 4 or 5 short sharp spines, spines longer and stronger from most proximal to most distal, surface of tibia notched between spines. Metatibia straight, slender. Metafemur slender, arcuate on lateral margin, sinuate on medial margin. Abdominal apex with narrow apicomedian notch.

Etymology. Named in reference to the geographical distribution.


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