Oecetis rostra, 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 : 222

Oecetis rostra sp. nov.

Figs 62–66

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 New Caledonian Oecetis in the shape of the coxopodites, which in lateral view are tall at the base and extend posterad as slender processes weakly curving caudad; in ventral view they are basally very wide, with a sharply pointed basomesal plate. Oecetis rostra sp. nov. resembles O. multidentata sp. nov. in having simple and slender coxopodites, a long curving posterior spine of tergum X, and many small, spine-like teeth in the phallus. Oecetis rostra sp. nov. can be separated from O. multidentata sp. nov. by its coxopodites curving slightly caudad in lateral view, taller superior appendages in lateral view, more-slen- der main branch of tergum X in lateral view and two slender lobes of the main branch of tergum X in dorsal view.

Description, male. Length of each forewing 5.4–6.5 mm (N = 2). Genitalia ( Figs 62–66 ) about as long as tall in lateral view. Segment IX oriented vertically, ventral part about two-times as long as dorsal part in lateral view; on each side anterior margin gently undulating; posterior margin with upper posterolateral projection and lower posterolateral process of segment IX both short and tall; longitudinal apodeme absent; acrotergite of segment IX small, forming widely separated pair of wart-like clusters of punctations, each cluster slightly wider than posterior spine in dorsal view; pair of dorsal semimembranous processes of segment IX stout, each as long as broad; membranous areas absent. Main branch of tergum X forming pair of lateral lobes, needle-shaped in lateral view, about twice as long as superior appendages, semimembranous, oriented posteroventrad, weakly curving ventrad along their length, without setae, apically pointed in lateral view; in dorsal view lobes forming finger-like processes well separated mesally, rounded posteriorly. Posterior spine of tergum X originating at base of main branch, parallel-sided, narrow and parallel-sided along its length in lateral view, gradually curving ventrad; in dorsal view parallel-sided, apically slightly dilated and rounded. Superior appendages about as long as tergum IX in lateral view, tall, oval in lateral and dorsal views. Each coxopodite with tall base, narrowing into slender, parallel-sided process curving slightly ventrad from one-third its length in lateral view; in ventral view each with wide base produced into pointed lobes almost meeting mesally; distal five-sixths parallel-sided, curving mesad in basal half; large setae absent. Phallus as long as coxopodites, irregular in shape, raptor-beak shaped posteriorly in lateral view, membranous part with several small spines; left side with separate lateral process from mid-length; in ventral view narrower and round anteriorly, irregularly shaped.

Male holotype: New Caledonia, Province Nord, Mont Panié , stream at camp, 20.58167°S, 164.76472°E, 1311 m, 9.xii.2003, Malaise trap, loc 073a, leg. K.A. Johanson, DNA voucher JC1 .

Paratype: 1 male: same data as holotype, except DNA voucher JB9 .

Etymology. The Latin feminized noun in apposition rostra means “beak,” referring to the raptor-beak shape of the posterior part of the phallus in lateral view.

Figures

FIGURES 62–66. Genitalia of Oecetis rostra sp. nov., male holotype. 62, left lateral; 63, dorsal; 64, ventral; 65, phallus, left lateral; 66, phallus, ventral.