Hydraena marojejy, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 100-101

Hydraena marojejy , new species

Figs. 89 (habitus), 91 (aedeagus), 270 (map)

Type Material. Holotype (male): Antsiranana, Parc National de Marojejy, Antranohofa, 26.6 km 31° NNE Andapa, 10.7 km 318° NW Manantenina, sifted litter (leaf mold, rotten wood) montane rainforest, elev. 1325 m, 14° 26' S, 49° 44' E, 18 xi 2003, B.L.Fisher (BLF 9080) ( CAS). Paratypes: Same data as holotype (3 CAS).

Differential Diagnosis. Distinguished from other members of the group by the comparatively large mesoventral plaques, each of which is larger than the area separating them. Otherwise, the habitus is very similar to that of H. ambohitantely . The aedeagi of the two species are quite dissimilar; that of H. marojejy notable in the large (in lateral view) flattened distal lobe that narrows to form a pick-like process.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.83/0.83; head width 0.44; pronotum 0.42/0.65, PA 0.52, PB 0.54; elytra 1.18/0.83.

Dorsum brown to reddish brown, clypeus slightly lighter than frons; elytral epipleurs lighter than venter; legs brown; maxillary palpi testaceous, distal ½ of last palpomere not darker.

Head and pronotum moderately finely sparsely punctate. Pronotal punctures slightly larger than those of frons; interstices on disc ca. 2–3xpd anteriorly and posteriorly, shining. Mentum with marginal band of punctures, otherwise microreticulate, dull; postmentum microreticulate, dull. Genae raised, shining, with posterior ridge.

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

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

Ratios of P2 width and plaque shape (P2/w-midlength/l/s) ca. 1/3/5/2. P1 slightly wider than P2 at midlength; median carina very weakly sinuate in profile. P2 l/w-midlength ca. 6/1, sides tapering to apex and on same level as and contiguous with anteromedian carina of metaventrite. Plaques large, oval or kidney-shaped, parallel, wider than the area separating them, very slightly raised, located at sides of median depression. Metaventrite anteromedian carina ca. as long as plaques, not quite attaining anterior level of plaques; moderately long, strong longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at arcuate posterior margin ca. 4x width of P2 at midlength. Protibia straight or very weakly arcuate, widest at ca. distal 0.25. Mesotibia straight, widest near midlength, medial margin notched in distal 0.25 and here bearing row of 3 or 4 short sharp spines, length of spines increasing from most proximal to most distal. Metatibia straight, moderately wide. Metafemur more strongly arcuate on lateral than medial margin. Abdominal apex with small, slightly asymmetrical apicomedian notch.

Etymology. Named in reference to the geographical distribution.