Oecetis fibra Chen & Morse

Quinteiro, Fábio B. & Calor, Adolfo R., 2012, A new species of Oecetis McLachlan, 1877 (Trichoptera: Leptoceridae) from Southeast Brazil: Validation of an unpublished species, Zootaxa 3442, pp. 53-61 : 54-56

Oecetis fibra Chen & Morse , new species

( Fig. 1 )

This species was recognized by Chen (1993) based on one specimen only, but the PhD thesis of Chen was not published. Dr. Morse, advisor of Chen, was contacted and he authorized us to describe the species formally based on more than one specimen, but we consider the original authors as Chen & Morse following the ICZN (1999, Recommendation 51E).

Diagnosis. The new species can be distinguished from the others of Quaria by the presence of a pair of sclerotized, cylindrical dorsolateral processes, bent ventrad on the posterior half of almost the same length as the phallic apparatus. An additional character is the long phallus with no projections and a long endotheca.

Male: Body length 5.5 mm (n=6). Forewing length 6.7 mm (n=6).

Head: Color pale yellow (alcohol). Antennae very long, about 3 times as long as forewings; scape stout; pedicel cylindrical. Maxillary palps pale yellow, densely covered by setae, 5-segmented, all segments subequal in length and width. Labial palps pale yellow, 4-segmented.

Thorax: pale yellow. Forewings flat, without spots or bands ( Fig. 1 A). Hind wings with forks I, III and V ( Fig. 1 B); row of long setae along base of posterior margin. Legs pale yellow. Midlegs each with longitudinal row of spines over inner distal half of femur, all along tibia and tarsal segments. Tibial spurs on successive legs on each side 0,2,2.

Abdomen: Membranous and without modifications on segments I–VIII. Sclerotized segment IX annular and narrow, bearing pair of cylindrical dorsolateral processes, curved ventrad and nearly forming semicircle, tapering apically, as long as phallic apparatus in lateral view ( Fig. 1 D); dorsolateral processes curved mesad to midline in dorsal view ( Fig. 1 C). Preanal appendages cylindrical, apex digitate, barely exceeding length of rodlike dorsomesal process of tergum X (upper part of tergum X, Chen 1993), setose. Rodlike dorsomesal process of tergum X, between preanal appendages, slightly longer than the preanal appendages, with small apical setae in dorsal view ( Fig. 1 C). Body of tergum X (lower part of tergum X, Chen 1993) semi membranous, divided medially by Vshaped incision, forming two processes apically, each broad basally and acute apically in dorsal view ( Fig. 1 C). Inferior appendages each 1-segmented, long, broad basally and with posterior portion digitate, setose, with small, rounded basal hump dorsally in lateral view ( Fig. 1 D); ventral lobe rounded, smooth, in lateral view ( Fig. 1 D), quadrate in ventral view ( Fig. 1 E). Phallus long, slightly asymmetrical ( Fig. 1 G), about as long as dorsolateral processes of tergum IX, curved ventrad ( Figs. 1 D, 1F).

Larva, pupa, and female unknown.

Material examined. Holotype: Brazil: São Paulo: Salesópolis, Estação Biológica Boracéia, Córrego Venerando, 09.xii.2005, light trap U.V./white lights, Froehlich, C.G. et al. – 1 male (alcohol; MZUSP). Paratypes: same data as holotype except Pedregulho, Furnas São Pedro, 22.vi.2010, Mateus, S, Lecci, L.S.– 1 male (alcohol; MZUSP); same except Bertioga, waterfall at the end of Torre 47 path, 17.ix.2006, light trap U.V./white lights, Calor, A., Roque, F., Siqueira, T.– 4 males (alcohol; UFBA, UMSP).

Chen (1993) described this species based on only one specimen (“ USNM ” = NMNH) labeled with these data: “ Casa Grande , sp. pedreira, a luz, 15-xi-1974, C.G. Froehlich. ” It is the same locality as the holotype we propose here and we include it as a paratype in the type series.

Distribution. Brazil (São Paulo State).

Etymology. The name is given by Chen (1993) from Latin, meaning “thread, filament, sinew,” referring to the slender shape of the dorsolateral process of segment IX.

Taxonomic remarks. Based on the presence of the dorsolateral processes on segment IX, it is possible to say that this species belongs to the subgenus Quaria (sensu Chen, 1993). Another character that makes this evident is the greater development of the phallic apparatus in opposition to Oecetis avara ( Banks, 1895) or Oecetis punctipennis ( Ulmer, 1905) , for example. Although characters like the cylindrical preanal appendages and the rodlike dorsomesal process over the body of tergum X are usual for the subgenus, as seen in Oecetis falicia Denning, 1966 (in Denning & Sykora, 1966), and Oecetis prolongata Flint, 1981 , the shape of the phallic apparatus, the inferior appendages and the dorsolateral processes make this species different of any other species.

Comparing this species with O. paranensis and O. rafaeli , the species recorded in Brazil that belong to subgenus Quaria (sensu Chen, 1993), it is possible to observe several differences. Oecetis paranensis has a triangular dorsolateral process on each side of segment IX, while O. fibra n. sp. has a thread-like process on segment IX. Moreover, O. paranensis has shorter inferior appendages and phallic apparatus when compared to O. fibra n. sp. and possesses a straight paramere spine, which is absent in O. fibra n. sp.

Comparing the new species with O. rafaeli , the later species has straight dorsolateral processes on segment IX, while in O. fibra n. sp. they are curved ventrad. Moreover, the preanal appendages of O. rafaeli are small and stout, while in the new species they are cylindrical and digitate. Oecetis rafaeli also has an undivided body of tergum X and a paramere spine in the phallic apparatus, while O. fibra n. sp. has a divided tergum X and no paramere spine.

Figures

FIGURE 1. Oecetis fibra Chen & Morse, n. sp. A—right forewing. B—right hind wing. C—male genitalia, dorsal. D—male genitalia, left lateral. E—male genitalia, ventral. F—phallic apparatus, left lateral. G—phallic apparatus, dorsal.