Oecetis oberdorffi new species

Fig. 9

Oecetis oberdorffi n. sp. is closely related to O. paranensis Flint (1982a) . Segment IX, tergum X, and the inferior appendages are similar in the 2 species, but there are small and consistent differences between them. Tergum X is triangular in the new species and gradually narrowed at the tip. Tergum X of O. paranensis is abruptly narrowed from midlength to the tip. In dorsal view, tergum X has a U–shaped excision in O. oberdorffi n. sp., whereas this median excision is V–shaped in O. paranensis . The preanal appendages in the new species are longer and narrower than those of O. paranensis . In O. paranensis, the inferior appendages are generally square, whereas those of O. oberdorffi n. sp. are mitten-shaped in lateral view.

Specific diagnosis. Tergum X broad at the base and gradually narrowed at the tip in lateral view; tergum X with deep U-shaped excision; inferior appendage with dorsal process square and apex digitated and rounded at the tip in lateral view.

Adult. Length of each forewing: 5 mm. Forewing with R2+3 branched beyond the apex of Sc, below midpoint of stigma (defined by apex of R1). Hind wings with R2+3 unforked, Cu1 with fork (Fig. 9 A).

Male genitalia. Segment IX annular, with 2 dorsal knobs (Figs 9 B–C). Preanal appendages oval, elongate, with rounded apices (Figs 9 B–C). Tergum X triangular and gradually narrowed at tip in lateral view (Fig. 9 B); bilobed with deep U-shaped median excision in dorsal view (Fig. 9 C). Inferior appendages broad, each with dorsal margin bearing dorsolateral square process, apical portion elongate and rounded, ventral margin curved, excision between processes U-shaped in lateral view (Fig. 9 B); inferior appendages each broad at base and narrowed at tip, bearing median rounded process; apex slightly curved mesad at midlength in ventral view (Fig. 9 D). Phallic apparatus short, curved and membranous at tip, with transverse ventral sulcus at the midlength in lateral view (Fig. 10 E); slightly broad at base and tip and narrowed at midlength in dorsal view (Fig. 9 F).

Holotype male. BOLIVIA: Bella Vista, Lake Granja, 13°15'50''S, 63°42'33''W, 06.v.2006, (IML).

Paratypes. 2 males, same as holotype, (CBF-UMSA), (IML).

Etymology. This species is dedicated to our friend and colleague, Thierry Oberdorff.