Oecetis tumida, Blahnik, Roger J. & Holzenthal, Ralph W., 2014

Blahnik, Roger J. & Holzenthal, Ralph W., 2014, Review and redescription of species in the Oecetis avara group, with the description of 15 new species (Trichoptera, Leptoceridae), ZooKeys 376, pp. 1-83 : 57-59

Oecetis tumida sp. n. Figs 24, 48, Map 1

Diagnosis.

Oecetis tumida is more or less intermediate in characters between Oecetis angularis sp. n. and Oecetis protrusa sp. n., agreeing with the former in the general shape of the inferior appendages, and with the latter in having the ventral apex of the phallobase somewhat convexly bulged preapically. The holotype specimen is from a population that is sympatric with Oecetis protrusa . In general, though, the phallobase is shorter and more bulbous apically than in Oecetis protrusa . In addition to the genitalic differences, the specimens were slightly larger than the co-occurring specimens of Oecetis protrusa . The species is most likely to be confused with Oecetis angularis , in part due to the similarity in color and size of the 2 species, but especially due to the shape of the inferior appendages, which have an obtusely angled ventral lobe that is very weakly, but angularly projecting. The convex preapical bulge on the phallobase in Oecetis tumida , and the absence of a distinctly V-shaped apex, in caudal view, should distinguish them.

Adult.

Forewing length: male (9.0-10 mm) Color pale yellowish to slightly brownish-yellow (similar to Oecetis mexicana ); forewing spots distinct, spots at base of discal and thyridial cells large or moderately large, other spots smaller; veins of forewing chord widely spaced, r and r-m veins slightly closer; chord with small spots at juncture of major veins, spots at opposite ends of chord slightly larger; spots at apices of major veins small but distinct, pigmentation largely confined to vein. Setae along veins in apical part of forewing elongate, semi-prostrate, laterally diverging. Fringe of setae along costal margin of forewing moderate in length, somewhat projecting, not conspicuously erect.

Male genitalia.

Segment IX very short, with elongate setae along posterolateral margin. Tergum X with narrow, deflexed mesal lobe, lobe relatively elongate, somewhat lobulate (expanded) apically, apex with small sensilla; lobe continuous basoventrally with short paired lateral membranous projections. Preanal appendage moderately elongate, length about 3 times maximum width, simple in structure, apical setae elongate. Inferior appendage with rounded dorsal lobe and angularly projecting ventral lobe; ventral lobe very weakly projecting, forming approximately right to distinctly obtuse angle with dorsal lobe, posterior margin of ventral lobe, as viewed ventrally (Fig. 24F), with distinctly angular bend near base; basomesal projection weakly developed, forming short rounded projection with short, stiff setae; dorsal lobe with stout, mesally-curved setae on dorsal margin and stout, ventrally-curved setae on mesal surface. Phallobase, as viewed laterally, relatively short, distinctly inflated apically; as viewed laterally with weakly developed, convex bulge preapically on ventral margin; as viewed caudally, with apex inflated, broadly U-shaped or V-shaped, not keeled ventrally (Fig. 24C). Phallotremal sclerite prominent, basally forming short tubular collar, ventral margin projecting, apex acute; asymmetrical lateral sclerite apparently absent.

Holotype.

Male (pinned), COSTA RICA: Limón: Res. Biol. Barbilla, Río Dantas, 15 km (road) S Pacuarito, 9°59.640'N, 83°26.580'W, el 300 m, 27-30.i.1992, Holzenthal, Muñoz, Kjer (UMSP) (INBIOCRI000372044).

Paratypes.

COSTA RICA: Guanacaste: Quebrada Garcia, 10. 6 km ENE Quebrada Grande, 10.862°N, 85.428°W, 470 m, 8.iii.1986, Holzenthal & Fasth, 1 male, 1 female (alcohol) (NMNH); Río Los Ahogados, 11.3 km ENE Quebrada Grande, 10.865°N, 85.423°W, el 470 m, 7.iii.1986, Holzenthal & Fasth, 1 male, 2 females (alcohol) (UMSP); Limón: same data as holotype, 1 male (pinned) (UMSP); Puntarenas: Río Singri, ca. 2 km (air) S Finca Helechales, 9°3.420'N, 83°4.920'W, el 720 m, 21.ii.1986, Holzenthal, Morse, Fasth, 1 male (alcohol) (UMSP).

Etymology.

This species is named Oecetis tumida , after the Latin word tumidus, meaning swollen, and referring to the apex of the phallobase in this species, which is distinctly swollen and usually has a slight, but noticeable, preapical ventral bulge.