Triaenodes oscitus Mueller & Johanson

Johanson, Kjell Arne, Eriksson, Maertha, Mueller, Hanna & Li, Helena Puranen, 2012, Description of three new Triaenodes species from Fiji (Trichoptera, Leptoceridae), ZooKeys 244, pp. 21-31 : 25-26

Triaenodes oscitus Mueller & Johanson sp. n. Figs 2, 9-13

Diagnosis.

The species resembles Triaenodes rebellus sp. n. in the shape of the ventral branch of the coxopodites and basomesal processes, but dorsal branch of each coxopodite is absent. The dorsal appendages of oscitus resemble those of Triaenodes grifo Malicky, 2005, but the upper part of tergum X of oscitus is longer.

Description, male.

Wings (Fig. 2). Forewing damaged, hind wing 4.1 mm (N=1).

Forewing: stem of M absent; forks I and V present; apex missing in holotype; membrane pale, except in distal one-third with two almost vertical series of dark spots, and a larger dark patch above vertical series. Hyaline area at anastomosis. Basal two-thirds with irregular pale fields. Hind wing: uniformly gray, with faint spots at apical half.

Genitalia (Figs 9-13). Segment IX in lateral view with slightly convex anterior margin, dorsal margin short, continuous with dorsal margin of tergum X; ventral two-thirds strongly produced into posterior lobe; posterior lobe with weakly undulating dorsal margin and nearly straight ventral margin except bending ventrally at apex, posterior margin almost truncate. Large triangular, vertical, posteriorly oriented plate located laterally and at mid-length of segment IX, forming narrow, posteriorly orienting processes. In ventral view anterior margin deeply concave; widest before lateral plates, with slightly concave lateral margins; uniformly narrowing after lateral plates. Posterior margins distinct laterally, mesally apparently fusing with gonopods. Cerci elongate, straight, serrated along their lengths, scattered setose, with row of minute setae along anterior three-quarters of ventral margin; in lateral view oriented almost horizontally, basal one-fifth about two times thicker than distal part; in dorsal view slightly diverging, equally wide along their lengths. Tergum X divided into well-developed upper and lower part. Upper part of tergum X slender, about as long as each cercus; slightly curvilinear ventrally along its length in lateral view; basally wide, slender after one-third its length in dorsal view, apex club-shaped, with short, stout setae. Width of base and apex subequal in lateral view. Lower part of tergum X branching at base into two long, needle-shaped processes, clearly longer than upper part of tergum X, curved ventrally along their lengths, reaching further posteriorly than apex of dorsal part of tergum X; in dorsal view slightly diverging. Gonopods each divided into one-branched coxopodite and basomesal process; about two-fifths as long as each cercus. Coxopodites with scattered setae; each with row of smaller setae along central part of dorsal margin; wide at base in lateral view, stepwise narrowing from about one-third, almost sickle-shaped; apex produced dorsally, nearly tangential with phallus. In ventral view, basal one-quarter of coxopodites separated by longitudinal suture, well-separated from one-quarter, each coxopodite forming dorsoventrally flattened, spoon-shaped plate, with serrated mesal margin; apices of coxopodites diverging. Left coxopodite shorter than right coxopodite, apically blunt. Basomesal processes about two-thirds as long as coxopodites; sickle-shaped in lateral view, each process oriented dorsally at base, curving posterad and slightly broadening towards apex, bearing strong, lateroventrally and slightly anteriorly directed spines. In ventral view processes running parallel along their lengths; each process with slightly narrowing apex, mesal margin almost straight, lateral margins with small indentations. Phallic organ widest at base and endotheca, narrowest immediately before endotheca; in lateral view with nearly triangular phallobase; phallotheca slender, widening distally and strongly curving ventrally at about mid-length. In dorsal view endotheca forming irregular lobes.

Remarks.

The right cercus is broken at mid-length in the holotype.

Material examined.

Holotype male: Fiji: Sigatoka Province, Sigatoka Sand Dunes National Park, coastal forest, 18°10'S, 177°30'E, 10 m, Malaise trap, 22. ix– 8.x.2002, leg. M. Irwin, E. Schlinger & M. Tokoka’a. [FNIC, alcohol]

Etymology.

Oscitus , from Latin oscito, gape or open mouth in English, in reference to the shape of the male gonopods in lateral view.