Oecetis multidentata, Johanson & Mary & Sjöberg & Malm, 2020

Johanson, Kjell Arne, Mary, Nathalie Jeanne, Sjöberg, Tin & Malm, Tobias, 2020, Eighteen new species of Oecetis McLachlan 1877 (Trichoptera, Leptoceridae) from New Caledonia, Zootaxa 4809 (2), pp. 201-240 : 217-220

Oecetis multidentata sp. nov.

Figs 51–56

Diagnosis. The species is distinguished from many Australasian Oecetis species by the absence of modified tergites on segment VIII and forward. It resembles other Oecetis species by having a strongly prolonged posterior spine of tergum X that is curved ventrad. The prominent posterior spine of tergum X is similar to that of O. dorsospina sp. nov., but O. multidentata sp. nov. can be distinguished from O. dorsospina sp. nov. by the absence of a dorsal branch of each coxopodite and a more strongly curved posterior spine in lateral view.

Description, male. Length of each forewing 4.5–4.8 mm (N = 3). Genitalia (Figs 51–56) longer than tall in lateral view. Segment IX in lateral view oblique, in lateral view with dorsum situated slightly posterior of venter, ventral part about as long as dorsal part in lateral view; on each side anterior margin convex along most of its length; posterior margin with small lower posterolateral process nearly indistinguishable, situated immediately above base of coxopodite; upper posterolateral processes large, broadly rounded, situated below superior appendages; acrotergite small, forming pair of rounded warts, each almost as wide as width of posterior spine in dorsal view; dorsal semimembranous processes of segment IX absent, membranous areas absent. Main branch of tergum X forming single, plate-like lobe, slender in lateral view, reaching as far posteriorly as coxopodites, semimembranous, almost straight, oriented posteroventrad, with several apical setae; apex slender, blunt in lateral view; in dorsal view forming broad rectangular plate with undulating posterior margin and tiny mesal notch. Posterior spine of tergum X originating at base of main branch, with narrow base, widening along its length in lateral view, at distal two-thirds strongly bent ventrad, with rounded apex in lateral view; in dorsal view parallel-sided along most of its length, with pointed apex; apex triangular in ventral view. Superior appendages short, about half as long as coxopodites, almost parallel-sided in lateral view, oval in dorsal view. Each coxopodite slender in lateral view, basal quarter slightly taller than distal parts in lateral view; almost straight, with weakly up-turned apex in lateral view; in ventral view almost meeting basomesally, mesal margins irregularly expanded mesad at mid-length; large setae absent. Phallus as long as tergum X, irregularly shaped; one large and several small tooth-like spines situated in dorsal membranous part.

Male holotype: New Caledonia, Province Sud, Dumbéa River, Branche Nord, 2.2 km SE summit of Mont Piditéré , 22°07.503’S, 166°29.899’E, 25 m, 21.i.2004, light trap, loc 124a, leg. K.A. Johanson & C. Pöllabauer, DNA voucher JK3 .

Paratypes: 1 male: New Caledonia, Province Sud, Couvelée River at Haute Couvelée, 2.8 km SV summit of Mont Piditéré , 3.5 km NNE Dumbéa, 22°07.488’S, 166°28.034’E, 27 m, 28.xi.2003, light trap, loc#051, leg. K.A. Johanson, DNA voucher JN7 . 1 male: New Caledonia, Province Sud, Dumbéa river, Branche Sud , 22°08.344’S, 166°30.147’E, 42 m, 03.xi.2003, light trap, loc#006, leg. K.A. Johanson, DNA voucher JA6 .

Etymology. The Latin adjective multidentata means “many-toothed,” referring to the cluster of posteriorly oriented teeth-like processes in the phallus.