Hydraena inseriata, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 81-83

Hydraena inseriata , new species

Figs. 70 (habitus), 72 (aedeagus), 261 (map)

Type Material. Holotype (male): Antananarivo, Anjozorobe, Ravoandrina, Riv. Ampanakamonty near campsite, lower course forest, elev. 1280 m, 18° 13' S, 47° 31' E, 21 vii 2001, Gerecke & Goldschmidt (MD 11b) NMW) . Paratypes (29): Antananarivo, Anjozorobe (Antananarivo), Ravoandrina, Riv. Ampanakamonty near campsite, elev. 1280 m, 18° 13' S, 47° 31' E, 21 vii 2001, Gerecke & Goldschmidt (MD 11d) (11 NMW), ( MD 11 c) (4 NMW), ( MD 11 ) (4 NMW); Anjozorobe (Antananarivo), Ravoandrina , Ruisseau Andohana Andreba (affl. of Riv. Ampanakamonty), pool, elev. 1250 m, 18° 13' S, 47° 31' E, 25 vii 2001, Gerecke & Goldschmidt (MD 15a) (2 NMW); Anjozorobe (Antananarivo), Ravoandrina , Ruisseau Andohana Andreba (affl. of Riv. Ampanakamonty), riffle, elev. 1250 m, 18° 13' S, 47° 31' E, 25 vii 2001, Gerecke & Goldschmidt (MD 15b) (4 NMW); Anjozorobe (Antananarivo), Ravoandrina , Ruisseau Anjajely , Andreba , elev. 1250 m, 18° 13' S, 47° 31' E, 27 vii 2001, Gerecke & Goldschmidt (MD 15) (1 NMW); Anjozorobe (Antananarivo), Riv. Ranonisoanavola, larger str. E from main mountain chain, elev. 1200 m, 18° 13' S, 47° 31' E, 23 vii 2001, Gerecke & Goldschmidt (MD 12) (3 NMW).

Differential Diagnosis. Differentiated from other members of the species group, except H. levifurcata , by combination of the habitus and the random elytral punctures. The two species being similar in shape, color, and ventral characters, reliable determinations will require examination of the aedeagi, which differ markedly ( Figs. 72, 80).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.70; head width 0.38; pronotum 0.38/0.53, PA 0.42, PB 0.41; elytra 0.97/0.70.

Dorsum dark brown to slightly reddish brown, frons and pronotal disc darkest; legs brown to dark brown; maxillary palpi light brown.

Head with clypeus finely and sparsely punctulate, lateral margins microreticulate; frons moderately coarsely densely punctate near eyes, interstices sometimes narrow walls, weakly shining, disc less coarsely and less densely punctate, interstices 1–4xpd, shining. Pronotum moderately coarsely and moderately densely punctate laterally and in PF1 and PF2, punctures on disc much finer and much sparser, interstices 1–5xpd, shining. Mentum very finely punctulate, almost impunctate, very effacedly microreticulate, shining; postmentum microreticulate in small median depression, surrounding area shining. Genae roundly raised, shining, posterior ridge absent, but very shallow short sulcus on each side.

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

Elytra arcuate laterally; posterior declivity steep, summit slightly before midlength, elytra appearing slightly humped; elytra transversely very convex, especially at posterior 3/5; lateral explanate margins wide; elytral punctures round, random, in basal 0.3 distinctly larger than largest punctures on pronotum, interstices 0.5–1xpd, shining, punctures on posterior declivity very fine and sparse. Apices in dorsal aspect conjointly sharply rounded, in posterior aspect margins do not form angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s [posteriorly]) ca. 1/0.3/2/1. P1 as wide as P2; median carina very weakly sinuate in profile. P2 l/w ca. 2/1, sides converging posteriorly, apex blunt and on same level as anteromedian carina of metaventrite. Plaques narrow, carinate lines, converging anteriorly and joining anteromedian carina, together forming inverted Y-shape, separated basally by ca. 4x plaque width, located at sides of deep median depression. Metaventrite anteromedian carina ca. same length as plaques; long longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity to slightly past midlength. AIS width at arcuate posterior margin ca. 2x P2. Protibia straight, slender. Mesotibia very slightly arcuate, medial margin near midlength with 2–3 very short sharp spines, margin shallowly notched between spines. Metatibia very slightly arcuate. Metafemur slender, arcuate on lateral margin, very weakly sinuate on medial margin. Abdominal apex with small apicomedian notch.

Etymology. Named in reference to the non-serial elytral punctures.