Oecetis triramosa, 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 : 224-226

Oecetis triramosa sp. nov.

Figs 67–72

Diagnosis. This species is distinguished from many of the Australasian Oecetis species by the absence of modified tergites on segment VIII and forward. The species is unique among Oecetis in the shape of the coxopodites, which in lateral view are tall and with three branches directed dorsad and posterad; in ventral view forming wide plates that almost meet mesally. Oecetis triramosa sp. nov. resembles O. australis ( Banks 1920) , from Australia, in the shape of the coxopodites, its long and slightly curving posterior spine of tergum X, and the sharply pointed lobes on the main branch of tergum X. Oecetis triramosa sp. nov. is separated from O. australis by having a two-lobed main branch of tergum X, wider superior appendages in dorsal view, and more-rounded basal parts of coxopodites in ventral view.

Description, male. Length of each forewing 5.3–7.6 mm (N = 24). Genitalia ( Figs 67–72 ) about as long as tall in lateral view. Segment IX oriented vertically, ventral part oval in lateral view, much longer than dorsal part in lateral view; on each side anterior margin uniformly convex; ventral half of posterior margin with short lower posterolateral process of segment IX; Upper posterolateral process of segment IX absent; longitudinal apodeme absent; acrotergite of segment IX forming pair of wide wart-like clusters of punctures, each cluster about twice as wide as the width of posterior spine in dorsal view; pair of dorsal semimembranous processes of segment IX short, stout, directed posterad; membranous areas absent. Main branch of tergum X forming two lateral lobes, needleshaped and apically pointed in lateral view, about twice as long as superior appendages, semimembranous, straight along their length, directed posteroventrad, without setae; in dorsal view each lobe forming narrowly cone-shaped process, sharply rounded posteriorly. Posterior spine of tergum X originating at base of main branch, parallel-sided, narrow along its length in lateral and dorsal views, curving slightly ventrad from distal two-thirds; apex narrowly rounded in dorsal view. Superior appendages about one-third as long as posterior spine in lateral view, dorsal margin almost straight, ventral margin convex; broad in dorsal view, situated closely to each other. Each coxopodite with three thick, equally long, rounded posterior branches: one dorsal and two posterior; dorsal branch thumb-like with long setae; posteriorly oriented branches with megasetae mesally; in ventral view broad, mesobasal plates produced posterad with rounded ends. Phallus as long as rest of genitalia, almost tube-shaped, anteriorly slightly taller than posterior part and separated from posterior part by small constriction, with three long posteriorly oriented and apically hooked spines; base narrower that posterior part in ventral view, widening at middle.

Male holotype: New Caledonia, Province Nord, western slope of Mont Kugüö, Xwé Wida Di Stream , 2 km E Koh, 21°35.474’S, 165°50.776’E, 154 m, 20.xi–12.xii.2003, Malaise trap, loc#036, leg. K.A. Johanson, DNA voucher JA3 .

Paratypes: 2 males: same data as holotype, except DNA vouchers AQ7, JD4 . 2 males: New Caledonia, Province Sud , western slope of Mont Ningua, Kwé Néco Stream, at Camp Jacob , 3.7 km WNW summit of Mont Ningua , on Boulouparis–Thio Road , about 50 m upstream road, 21°43.613’S, 166°06.567’E, 150 m, 12.xii.2003 – 05.i.2004, Malaise trap, loc#054, leg. K.A. Johanson, DNA vouchers AR1, AS 3. 1 male: New Caledonia, Province Nord , Plaine des Gaïacs, Rivière Rouge, 14.2 km NW summit of Mont Rouge , 50 m upstream road RT1 Nouméa-Koné , 20°31.573’S, 164°46.690’E, 23 m, 2.i.2004, light trap, loc#104, leg. K.A. Johanson, DNA voucher JQ2 . 1 male: New Caledonia, Province Nord , Col des Roussettes, Wâ Wéépö Stream, 100 m upstream bridge on road RPN6 Bo-urail–Houaïlou , 7.9 km E summit of Mont Këiyöumâ , 21°24.771’S, 165°27.005’E, 166 m, 5–26.xii.2003, Malaise trap, loc#079, leg. K.A. Johanson, DNA voucher AQ4 . 1 male: New Caledonia, Province Nord , 50 m upstream bridge on Hienghène–Tnèdo road, 3.9 km S summit of Mont Tnèda , 2.4 km E Tnèdo, 20°43.099’S, 164°50.108’E, 27 m, 7.xii.2003, Malaise trap, loc#069, leg. K.A. Johanson, DNA voucher AP9 . 2 males: New Caledonia, Province Sud , western slope of Mont Ningua, Kwé Néco Stream, at Camp Jacob , 3.9 km W summit of Mont Ningua , on Boulouparis-Thio Road , about 50 m upstream road, 21°44.083’S, 166°06.298’E, 117 m, 29.xi–12.xii.2003, Malaise trap, loc#053, leg. K.A. Johanson, DNA vouchers JF8, JF9 . 1 male: New Caledonia, Province Nord , Mont Panié, River Padyéém , 400 m, 20°34.122’S, 164°48.147’E, 22–28.xi.2001, Malaise trap, loc#146 (16-2001), leg. K.A. Johanson, T. Pape, B. Viklund, DNA voucher JB2 . 1 male: New Caledonia, Province Sud , River Ouanéoue, at bride crossing road to Koghis Mountains, about 1.5 km from road RT1 Nouméa-Dumbéa , 22°10.861’S, 166°29.531’E, 11.i.2004, light trap, loc 024a, leg. K.A. Johanson, DNA voucher JC3 . 1 male: New Caledonia, Province Sud , Monts des Koghis, ca. 1.0 km from road RT1 between Nouméa and Dumbéa , water reservoir about 100x 100 m diameter, 22°10.919’S, 166°29.182’E, 91 m, 10.xi.2003, light trap, loc#020, leg. K.A. Johanson, DNA voucher JA4 . 1 male: New Caledonia, Prov. Sud , Sarraméa, Stream Xwé Wya , ca. 0.9 km NE Hôtel Evasion 130, 21°38.081’S, 165°51.735’E, 19.xi.2001, light trap, loc#131a (10-2001), leg. K.A. Johanson, T. Pape, B. Viklund, DNA voucher DN8 . 2 males: New Caledonia, Province Sud , Plateau de Dogny, Source of Dogny River, about 900 m SE summit of Plateau de Dogny , 21.61917°S, 165.88072°E, 919 m, 25.xi–16.xii.2003, Malaise trap, loc#046, leg. K.A. Johanson, DNA vouchers JF5, JF7 . 1 male: New Caledonia, Province Sud , Monts Kwa Ne Mwa, on road between Nouméa and Yaté , 800 m N Pont des Japonais, 22°11.043’S, 166°43.566’E, 120 m, 7–16.xi.2003, Malaise trap, loc#015, leg. K.A. Johanson, DNA voucher AS 4. 1 male: New Caledonia, Province Sud, Saint–Vincent , Bangou Stream, at bridge on road to Tribu de Bangou, 700 m N RT1 Nouméa–Tontouta road, 22°03.477’S, 166°15.718’E, 26.xi.2003, light trap, loc#050, leg. K.A. Johanson, DNA voucher AQ6 . 1 female: New Caledonia, Province Sud , Monts Kwa Ne Mwa, on road between Nouméa and Yaté , 800 m N Pont des Japonais, 22°11.043’S, 166°43.566’E, 120 m, 7– 16.xi.2003, Malaise trap, loc#015, leg. K.A. Johanson, DNA voucher JD6 . 1 female: New Caledonia, Province Sud , Monts Kwa Ne Mwa, on road between Nouméa and Yaté , Rivière des Pirogues , 22°11.225’S, 166°43.338’E, 100 m, 7.xi.2003, light trap, loc#016, leg. K.A. Johanson, DNA voucher JD3 . 1 male: New Caledonia, Province Sud , western part of Mont Ningua, Kwé Néco Stream, 3.9 km W summit of Mont Ningua , on Boulouparis–Thio Road , about 50 m upstream road, 21°44.359’S, 166°06.009’E, 117 m, 20.xi.2003 – 12.xii.2003, Malaise trap, loc#035, leg. K.A. Johanson, DNA voucher AS 6. 1 male: New Caledonia, Province Nord , Héémwâ Pwei River, 50 m upstream bridge on Touho–Hienghene road, 1.1 km N Paola, 20.76503°S, 165.10974°E, 22.xii.2003, light trap, loc#094, leg. K.A. Johanson, DNA voucher AQ5 . 1 male: New Caledonia, Province Sud , Monts Dzumac, source stream of Ouinné River , near cross point to mountain track, 22°02.439’S, 166°28.646’E, 805 m, 18.xi–4.xii.2003, Malaise trap, loc#029, leg. K.A. Johanson, DNA voucher AG4 .

Etymology. The Latin adjective triramosa , meaning “three-branched,” refers to the three-branched coxopodites and three hook-shaped spines projecting from the posterior part of the retracted phallus.

Figures

FIGURES 67–72. Genitalia of Oecetis triramosa sp. nov., male holotype. 67, left lateral; 68, dorsal; 69, ventral; 70, right coxopodite, dorsal; 71, phallus, left lateral; 72, phallus, ventral.